bluuebunny/crossref_metadata_2025 huggingface dataset:
Mycobacterium's Arrest of Phagosome Maturation in Macrophages Requires Rab5 Activity and Accessibility to Iron
Authors: Kelley Victoria A. , Schorey Jeffrey S.
Published: May 2003

Many mycobacteria are intramacrophage pathogens that reside within nonacidified phagosomes that fuse with early endosomes but do not mature to phagolysosomes. The mechanism by which mycobacteria block this maturation process remains elusive. To gain insight into whether fusion with early endosomes is required for mycobacteria-mediated inhibition of phagosome maturation, we investigated how perturbing the GTPase cycles of Rab5 and Rab7, GTPases that regulate early and late endosome fusion, respectively, would affect phagosome maturation. Retroviral transduction of the constitutively activated forms of both GTPases into primary murine macrophages had no effect on Mycobacterium avium retention in an early endosomal compartment. Interestingly, expression of dominant negative Rab5, Rab5(S34N), but not dominant negative Rab7, resulted in a significant increase in colocalization of M. avium with markers of late endosomes/lysosomes and increased mycobacterial killing. This colocalization was specific to mycobacteria since Rab5(S34N) expressing cells showed diminished trafficking of endocytic tracers to lysosomes. We further demonstrated that maturation of M. avium phagosomes was halted in Rab5(S34N) expressing macrophages supplemented with exogenous iron. These findings suggest that fusion with early endosomes is required for mycobacterial retention in early phagosomal compartments and that an inadequate supply of iron is one factor in mycobacteria's inability to prevent the normal maturation process in Rab5(S34N)-expressing macrophages.
Selective Caveolin-1–dependent Endocytosis of Glycosphingolipids
Authors: Singh Raman Deep , Puri Vishwajeet , Valiyaveettil Jacob T. , Marks David L. , Bittman Robert , Pagano Richard E.
Published: May 2003

We studied the endocytosis of fluorescent glycosphingolipid (GSL) analogs in various cell types using pathway-specific inhibitors and colocalization studies with endocytic markers and DsRed caveolin-1 (cav-1). Based on inhibitor studies, all GSLs tested were internalized predominantly (>80%) by a clathrin-independent, caveolar-related mechanism, regardless of cell type. In addition, fluorescent lactosylceramide (LacCer) colocalized with DsRed-cav-1 in vesicular structures upon endocytosis in rat fibroblasts. The internalization mechanism for GSLs was unaffected by varying the carbohydrate headgroup or sphingosine backbone chain length; however, a fluorescent phosphatidylcholine analog was not internalized via caveolae, suggesting that the GSL ceramide core may be important for caveolar uptake. Internalization of fluorescent LacCer was reduced 80–90% in cell types with low cav-1, but was dramatically stimulated by cav-1 overexpression. However, even in cells with low levels of cav-1, residual LacCer internalization was clathrin independent. In contrast, cholera toxin B subunit (CtxB), which binds endogenous GM1, was internalized via clathrin-independent endocytosis in cells with high cav-1 expression, whereas significant clathrin-dependent uptake occurred in cells with low cav-1. Fluorescent GM1, normally internalized by clathrin-independent endocytosis in HeLa cells with low cav-1, was induced to partially internalize via the clathrin pathway in the presence of CtxB. These results suggest that GSL analogs are selectively internalized via a caveolar-related mechanism in most cell types, whereas CtxB may undergo “pathway switching” when cav-1 levels are low.
Conservation of the Prion Properties of Ure2p through Evolution
Authors: Baudin-Baillieu Agnès , Fernandez-Bellot Eric , Reine Fabienne , Coissac Eric , Cullin Christophe
Published: May 2003

The yeast inheritable [URE3] element corresponds to a prion form of the nitrogen catabolism regulator Ure2p. We have isolated several orthologous URE2 genes in different yeast species: Saccharomyces paradoxus, S. uvarum, Kluyveromyces lactis, Candida albicans, and Schizosaccharomyces pombe. We show here by in silico analysis that the GST-like functional domain and the prion domain of the Ure2 proteins have diverged separately, the functional domain being more conserved through the evolution. The more extreme situation is found in the two S. pombe genes, in which the prion domain is absent. The functional analysis demonstrates that all the homologous genes except for the two S. pombe genes are able to complement the URE2 gene deletion in a S. cerevisiae strain. We show that in the two most closely related yeast species to S. cerevisiae, i.e., S. paradoxus and S. uvarum, the prion domains of the proteins have retained the capability to induce [URE3] in a S. cerevisiae strain. However, only the S. uvarum full-length Ure2p is able to behave as a prion. We also show that the prion inactivation mechanisms can be cross-transmitted between the S. cerevisiae and S. uvarum prions.
Interaction of Arl1-GTP with GRIP Domains Recruits Autoantigens Golgin-97 and Golgin-245/p230 onto the Golgi
Authors: Lu Lei , Hong Wanjin
Published: May 2003

A cellular role and the mechanism of action for small GTPase Arl1 have been defined. Arl1-GTP interacts with the GRIP domains of Golgin-97 and Golgin-245, a process dependent on conserved residues of the GRIP domains that are important for Golgi targeting. The switch II region of Arl1 confers the specificity of this interaction. Arl1-GTP mediates Golgi recruitment of Golgin-97 in a switch II-dependent manner, whereas tethering Arl1-GTP onto endosomes can mediate endosomal targeting of Golgin-97. Golgin-97 and Golgin-245 are dissociated from the Golgi when Arl1 is knocked-down by its siRNA. Arl1-GTP thus functions to recruit Golgin-97 and Golgin-245 onto the Golgi via interacting with their GRIP domains.
Schizosacchromyces pombeDpb2 Binds to Origin DNA Early in S Phase and Is Required for Chromosomal DNA Replication
Authors: Feng Wenyi , Rodriguez-Menocal Luis , Tolun Gökhan , D'Urso Gennaro
Published: May 2003

Genetic evidence suggests that DNA polymerase epsilon (Pol ϵ) has a noncatalytic essential role during the early stages of DNA replication initiation. Herein, we report the cloning and characterization of the second largest subunit of Pol ϵ in fission yeast, called Dpb2. We demonstrate that Dpb2 is essential for cell viability and that a temperature-sensitive mutant of dpb2 arrests with a 1C DNA content, suggesting that Dpb2 is required for initiation of DNA replication. Using a chromatin immunoprecipitation assay, we show that Dpb2, binds preferentially to origin DNA at the beginning of S phase. We also show that the C terminus of Pol ϵ associates with origin DNA at the same time as Dpb2. We conclude that Dpb2 is an essential protein required for an early step in DNA replication. We propose that the primary function of Dpb2 is to facilitate assembly of the replicative complex at the start of S phase. These conclusions are based on the novel cell cycle arrest phenotype of the dpb2 mutant, on the previously uncharacterized binding of Dpb2 to replication origins, and on the observation that the essential function of Pol ϵ is not dependent on its DNA synthesis activity.
Endoplasmic Reticulum Export of Glycosyltransferases Depends on Interaction of a Cytoplasmic Dibasic Motif with Sar1
Authors: Giraudo Claudio G. , Maccioni Hugo J.F.
Published: May 2003

Membrane proteins exit the endoplasmic reticulum (ER) in COPII-transport vesicles. ER export is a selective process in which transport signals present in the cytoplasmic tail (CT) of cargo membrane proteins must be recognized by coatomer proteins for incorporation in COPII vesicles. Two classes of ER export signals have been described for type I membrane proteins, the diacidic and the dihydrophobic motifs. Both motifs participate in the Sar1-dependent binding of Sec23p–Sec24p complex to the CTs during early steps of cargo selection. However, information concerning the amino acids in the CTs that interact with Sar1 is lacking. Herein, we describe a third class of ER export motif, [RK](X)[RK], at the CT of Golgi resident glycosyltransferases that is required for these type II membrane proteins to exit the ER. The dibasic motif is located proximal to the transmembrane border, and experiments of cross-linking in microsomal membranes and of binding to immobilized peptides showed that it directly interacts with the COPII component Sar1. Sar1GTP-bound to immobilized peptides binds Sec23p. Collectively, the present data suggest that interaction of the dibasic motif with Sar1 participates in early steps of selection of Golgi resident glycosyltransferases for transport in COPII vesicles.
Grr1-dependent Inactivation of Mth1 Mediates Glucose-induced Dissociation of Rgt1 from HXT Gene Promoters
Authors: Flick Karin M. , Spielewoy Nathalie , Kalashnikova Tatyana I. , Guaderrama Marisela , Zhu Qianzheng , Chang Hui-Chu , Wittenberg Curt
Published: May 2003

In budding yeast, HXT genes encoding hexose permeases are induced by glucose via a mechanism in which the F box protein Grr1 antagonizes activity of the transcriptional repressor Rgt1. Neither the mechanism of Rgt1 inactivation nor the role of Grr1 in that process has been understood. We show that glucose promotes phosphorylation of Rgt1 and its dissociation from HXT gene promoters. This cascade of events is dependent upon the F-box protein Grr1. Inactivation of Rgt1 is sufficient to explain the requirement for Grr1 but does not involve Rgt1 proteolysis or ubiquitination. We show that inactivation of Mth1 and Std1, known negative regulators of HXT gene expression, leads to the hyperphosphorylation of Rgt1 and its dissociation from HXT promoters even in the absence of glucose. Furthermore, inactivation of Mth1 and Std1 bypasses the requirement for Grr1 for induction of these events, suggesting they are targets for inactivation by Grr1. Consistent with that proposal, Mth1 is rapidly eliminated in response to glucose via a mechanism that requires Grr1. Based upon these data, we propose that glucose acts via Grr1 to promote the degradation of Mth1. Degradation of Mth1 leads to phosphorylation and dissociation of Rgt1 from HXT promoters, thereby activating HXT gene expression.
XRad17 Is Required for the Activation of XChk1 But Not XCds1 during Checkpoint Signaling inXenopus
Authors: Jones Rhiannon E. , Chapman J. Ross , Puligilla Chandrakala , Murray Johanne M. , Car Antony M. , Ford Christopher C. , Lindsay Howard D.
Published: May 2003

The DNA damage/replication checkpoints act by sensing the presence of damaged DNA or stalled replication forks and initiate signaling pathways that arrest cell cycle progression. Here we report the cloning and characterization of Xenopus orthologues of the RFCand PCNA-related checkpoint proteins. XRad17 shares regions of homology with the five subunits of Replication factor C. XRad9, XRad1, and XHus1 (components of the 9-1-1 complex) all show homology to the DNA polymerase processivity factor PCNA. We demonstrate that these proteins associate with chromatin and are phosphorylated when replication is inhibited by aphidicolin. Phosphorylation of X9-1-1 is caffeine sensitive, but the chromatin association of XRad17 and the X9-1-1 complex after replication block is unaffected by caffeine. This suggests that the X9-1-1 complex can associate with chromatin independently of XAtm/XAtr activity. We further demonstrate that XRad17 is essential for the chromatin binding and checkpoint-dependent phosphorylation of X9-1-1 and for the activation of XChk1 when the replication checkpoint is induced by aphidicolin. XRad17 is not, however, required for the activation of XCds1 in response to dsDNA ends.
Pex11-related Proteins in Peroxisome Dynamics: A Role for the Novel Peroxin Pex27p in Controlling Peroxisome Size and Number inSaccharomyces cerevisiae
Authors: Tam Yuen Yi C. , Torres-Guzman Juan C. , Vizeacoumar Franco J. , Smith Jennifer J. , Marelli Marcello , Aitchison John D. , Rachubinski Richard A.
Published: May 2003

Transcriptome profiling identified the gene PEX25 encoding Pex25p, a peroxisomal membrane peroxin required for the regulation of peroxisome size and maintenance in Saccharomyces cerevisiae. Pex25p is related to a protein of unknown function encoded by the open reading frame, YOR193w, of the S. cerevisiae genome. Yor193p is a peripheral peroxisomal membrane protein that exhibits high sequence similarity not only to Pex25p but also to the peroxisomal membrane peroxin Pex11p. Unlike Pex25p and Pex11p, Yor193p is constitutively expressed in wild-type cells grown in oleic acid-containing medium, the metabolism of which requires intact peroxisomes. Cells deleted for the YOR193w gene show a few enlarged peroxisomes. Peroxisomes are greatly enlarged in cells harboring double deletions of the YOR193w and PEX25 genes, the YOR193w and PEX11 genes, and the PEX25 and PEX11 genes. Yeast two-hybrid analyses showed that Yor193p interacts with Pex25p and itself, Pex25p interacts with Yor193p and itself, and Pex11p interacts only with itself. Overexpression of YOR193w, PEX25, or PEX11 led to peroxisome proliferation and the formation of small peroxisomes. Our data suggest a role for Yor193p, renamed Pex27p, in controlling peroxisome size and number in S. cerevisiae.
Stress and elastic-constant analysis by X-ray diffraction in thin films
Authors: Badawi F. , Villain P.
Published: May 2003

Residual stresses influence most physical properties of thin films and are closely related to their microstructure. Among the most widely used methods, X-ray diffraction is the only one allowing the determination of both the mechanical and microstructural state of each diffracting phase. Diffracting planes are used as a strain gauge to measure elastic strains in one or several directions of the diffraction vector. Important information on the thin-film microstructure may also be extracted from the width of the diffraction peaks: in particular, the deconvolution of these peaks allows values of coherently diffracting domain size and microdistortions to be obtained. The genesis of residual stresses in thin films results from multiple mechanisms. Stresses may be divided into three major types: epitaxic stresses, thermal stresses and intrinsic stresses. Diffraction methods require the knowledge of the thin-film elastic constants, which may differ from the bulk-material values as a result of the particular microstructure. Combining an X-ray diffractometer with a tensile tester, it is possible to determine X-ray elastic constants of each diffracting phase in a thin-film/substrate system, in particular the Poisson ratio and the Young modulus. It is important to notice that numerous difficulties relative to the application of diffraction methods may arise in the case of thin films.
Cationic disorder, microstructure and dielectric response of ferroelectric SBT ceramics
Authors: Muller Ch. , Jacob F. , Gagou Y. , Elkaïm E.
Published: May 2003

Polycrystalline samples of SrBi2Ta2O9(acronym SBT) have been prepared by means of solid-state reaction either using a classical route or by mechanochemical activation. For each compound, a structural analysis of the ferroelectric orthorhombic phase (space groupA21am) has been performed from the fitting of neutron and/or X-ray powder diffraction data using the Rietveld method. A cationic disorder on Bi3+and Sr2+crystallographic sites has been revealed, the Sr atoms occupying the Bi sites andvice versa. From diffraction peak broadening analyses of high-resolution synchrotron X-ray diffraction data, it has been shown that the two grinding methods (manual or mechanical) induce local strains, the average apparent strain being three times larger for the mechanically ground sample. In order to link microstructure and ferroelectric properties, the dielectric constant has been measured as a function of the temperature. It appears that the position and the shape of the dielectric anomaly strongly depend upon the composition and the route used to elaborate the powders. More exactly, for the mechanically ground powder, the large apparent strain, probably correlated to the strong cation exchange revealed by the structural refinement, leads to a significantly enhanced dielectric response.
ICSC: a program for calculating inelastic scattering cross sections for fast electrons incident on crystals
Authors: Oxley M. P. , Allen L. J.
Published: May 2003

A computer program which calculates inner-shell ionization and backscattering cross sections for fast electrons incident on a crystal is presented. The program calculates the inelastic scattering coefficients for inner-shell ionization, pertinent to electron energy loss spectroscopy and energy dispersive X-ray analysis, using recently presented parameterizations of the atomic scattering factors. Orientation-dependent cross sections, suitable for atom location by channelling enhanced microanalysis, may be calculated. Inelastic scattering coefficients that allow the calculation of orientation-dependent annular dark-field and Rutherford backscattering maps are calculated using an Einstein model. In all cases, absorption due to thermal diffuse scattering, also calculated using an Einstein model, can be included.
Quantitative basis for the rocking-curve measurement of preferred orientation in polycrystalline thin films
Authors: Toraya H. , Hibino H. , Ida T. , Kuwano N.
Published: May 2003

A quantitative basis for the rocking-curve measurement of the preferred orientation in polycrystalline thin films is presented. Gaussian functions are used for modeling the density distribution of the normals to the crystal plane around the normal to the specimen surface. An intensity formula for the rocking curve is derived from the kinematical theory applied to the case of asymmetric Bragg reflection. The density distribution is determined by the least-squares fit of a theoretical rocking curve to the observed curve, and a volume fraction of crystallites, whose normals to the crystal plane are present within a defined angular range, can be obtained from it. AlN and Au polycrystalline thin films were used for testing the present procedure. Parameter values of the model function, refined using both synchrotron radiation and laboratory X-rays, agree well with each other within the experimental errors although these intensity data sets were collected under different experimental conditions in instrumentation and wavelength. A distribution of depth-dependent preferred orientation in the AlN thin film was revealed by using double-layer and multiple-layer models. A very small degree of preferred orientation in Au thin films could also be measured. Parallel-beam optics and integrated intensities instead of peak height intensities are important for reliable rocking curve measurement.
Study of the structural evolution of the 10 Å unstable hydrate of kaolinite during dehydration by XRD and SAXS
Authors: Naamen S. , Jemai S. , Ben Rhaiem H. , Ben Haj Amara A.
Published: May 2003

This work deals with understanding the structural evolution of the dehydration of the 10 Å unstable hydrate of kaolinite. The method used to characterize this hydrate is based on a comparison between the experimental and the calculated X-ray diffraction profiles. The study was achieved in two steps: (i) the quantitative interpretation of 00lreflections enabled the determination of the number of intercalated water molecules, their positions and the stacking mode of the clay layers along the normal to the (a,b) plane; and (ii) the study of thehklreflections withhand/ork≠ 0 enabled the characterization of the structural evolution in the (a,b) plane of the hydrated kaolinite during dehydration. The hydrate is made up of two demixed phases. The first phase is homogenous and corresponds to a 10 Å hydrated kaolinite, characterized by two H2O molecules per Si2Al2O5(OH)4situated atZ= 7.1 Å from the surface oxygen. Two adjacent layers are translated with respect to each other, withT1= −0.155a+ 0.13b+ 10n. The abundance of this phase decreases during dehydration. The second phase is made up of 10 Å hydrated layers, 8.4 Å hydrated layers and 7.2 Å dehydrated kaolinite layers, randomly interstratified. The abundance of this second phase increases during dehydration. The corresponding interlayer shifts are respectivelyT21= −0.155a+ 0.13b+ 10nfor the 10 Å hydrated layer,T22= −0.355a+ 0.35b+ 8.4nfor the 8.4 Å hydrate andT23= −0.36a− 0.024b+ 7.2nfor the natural kaolinite. In addition to these interlayer shifts, some translation defects are introduced, such as −b/3, which exists in the initial kaolinite. The interpretation of the small-angle X-ray scattering (SAXS) patterns showed that the particle thickness remained the same before and after the hydration treatments, whereas X-ray diffraction (XRD) results indicated that the hydration of kaolinite caused a decrease of the mean number of layers \bar m per crystallite from 40 to 20 layers. This decrease is related to the presence of H2O molecules situated within the micropores in the kaolinite particles that leave their interlayer space after heating at 573 K. The resulting dehydrated compound is characterized by the same basal distance and mean number of layers \bar m per crystallite as for the natural kaolinite, while the proportion of the defects, such as the −b/3 translation, increases in the completely dehydrated compound (45%) compared with the natural kaolinite (10%).
In situmonitoring of powder reactions in percolating solution by wet-cell X-ray diffraction techniques
Authors: Warr Laurence N. , Hofmann Heiko
Published: May 2003

This note describes how the kinetics of powder reactions in percolating solution can be studied by X-ray diffraction using a wet-cell flow-through reaction chamber. The device can be routinely moved between diffractometer and controlled laboratory (pressure, temperature) conditions with the ease of a standard powder holder. Short-termin situmeasurements and long-termquasiin situmonitoring of dissolution and crystallization reactions are possible with a minimum of sample preparation and little disturbance of the system. Measuring time-dependent changes in the concentration of crystalline reactants and products provides information for quantifying reaction kinetics and for determining dissolution and crystal growth mechanisms. Results can be compared with changes in solution chemistry of the collected eluate, enabling a more complete reconstruction of heterogeneous crystal–solution reactions in open systems.
A systematic procedure for the decomposition of a powder diffraction pattern
Authors: Altomare Angela , Caliandro Rocco , Cuocci Corrado , Giacovazzo Carmelo , Moliterni Anna Grazia Giuseppina , Rizzi Rosanna
Published: May 2003

Ab initiocrystal structure solution from powder diffraction data can be attained by means of the two-stage method: first the integrated intensities of individual reflections are extracted from the experimental profile; then the extracted intensities are processed by direct methods to recover their phase. The efficiency of the direct-methods process is strongly affected by the accuracy of the extracted intensities and this is a serious drawback for the solution of organic compounds, where the presence of light atoms leads to a rapid decrease of the scattering at high angles. In order to overcome this problem, a procedure is proposed which generates a set of different intensity partitions for groups of reflections in strong overlap: the resulting decomposition trials are supplied to direct methods. The procedure is able to reduce the phase error at the end of the phasing process by up to 50° and enables the solution of organic structures with data resolution not worse than 1.5 Å in a reasonable computing time. The procedure has been implemented in theEXPOprogram, which makes use of the Le Bail extraction algorithm.
Optical birefringence imaging of the phase transition of K2Mn2(SO4)3
Authors: Hernández-Rodríguez C. , Geday M. A. , Kreisel J. , Glazer A. M. , Hidalgo-López A.
Published: May 2003

The present paper reports on the observation of the optical birefringence as a function of temperature of the langbeinite-type crystal K2Mn2(SO4)3by using an imaging version of the so-called rotating-polarizer method. This method provides separate moving images of the orientation of the optical indicatrix and the magnitude of the optical anisotropy, showing the domain-wall behaviour during temperature changes. Some new results on the domain behaviour of the phase transition of K2Mn2(SO4)3have been obtained. It is concluded that the sample single crystal consists of local regions, indicating the coexistence of two phases in this langbeinite-type crystal.
High-pressure X-ray diffraction study of bulk- and nanocrystalline GaN
Authors: Jørgensen J.-E. , Jakobsen J. M. , Jiang J. Z. , Gerward L. , Olsen J. Staun
Published: May 2003

Bulk- and nanocrystalline GaN have been studied by high-pressure energy-dispersive X-ray diffraction. Pressure-induced structural phase transitions from the wurtzite to the NaCl phase were observed in both materials. The transition pressure was found to be 40 GPa for the bulk-crystalline GaN, while the wurtzite phase was retained up to 60 GPa in the case of nanocrystalline GaN. The bulk moduli for the wurtzite phases were determined to be 187 (7) and 319 (10) GPa for the bulk- and nanocrystalline phases, respectively, while the respective NaCl phases were found to have very similar bulk moduli [208 (28) and 206 (44) GPa].
Cooler for obtaining crystals in a crucible furnace
Authors: Cabric B. , Janicijevic A.
Published: May 2003

An air cooler (`cold key') is presented with a movable branchy Tamman test tube (`test comb') installed in a laboratory crucible furnace for regulation and simultaneous crystallization tests at different temperature gradients and crystallization rate intervals, with the purpose of obtaining crystals. This method can also be applied in tube or chamber furnaces.
POVScript+: a program for model and data visualization using persistence of vision ray-tracing
Authors: Fenn T. D. , Ringe D. , Petsko G. A.
Published: May 2003

Macromolecular visualization is hampered by the fragmented set of available programs and the lack of cooperativity among them. The amount of visual information required for robust structural analysis is relatively difficult to generate and rarely allows further high-quality three-dimensional graphic rendering. Here, a modification ofMolScript[Kraulis (1991).J. Appl. Cryst.24, 946–950] is presented which contains the capability of the originalMolScript, the ability to carry out a majority of the options available in most other crystallographic visualization packages, as well as several new features of its own.POVScript+(currently version 1.62) allows anisotropic displacement ellipsoid rendering (read in as a second-rank tensor from a PDB file), electron-density polygonization (in several formats derived from a `marching tetrahedra' approach), volumetric rendering of electron density and GRASP/MSMS surface-map input/output. Finally,POVRayoutput is supported (viaa modified version ofPovScript) to generate high-quality renderings that are easily modified for any of a number of purposes (e.g.animations or altered textures).POVScript+provides a marked increase in the amount of structural and atomic detail possible, while still allowing a straightforward means of generating this information.
Use of double Göbel mirrors with high-temperature stages for powder diffraction – a strategy to avoid severe intensity fade
Authors: Whitfield Pamela S.
Published: May 2003

This paper describes an approach for countering an issue that can occur when using a high-temperature stage with a diffractometer equipped with double Göbel mirrors. The optical characteristics of the dual-mirror configuration make it more susceptible to intensity loss with sample displacement than conventional parallel-beam secondary optics. This issue has been apparent in the use of a high-temperature stage on a diffractometer equipped with dual mirrors, where data could not be obtained from the full room temperature to 1273 K range without resetting the sample height manually part way through the experiment. A simple technique involving controlled contouring of the sample surface has been demonstrated to allow data to be collected uninterrupted over the full temperature range, while retaining satisfactory intensities. The extent to which this technique extends the tolerable sample displacement range has been quantified using a computer-controlledXYZstage.
Measurement of high-quality diffraction data with a Nonius KappaCCD diffractometer: finding the optimal experimental parameters
Authors: Sørensen Henning Osholm , Larsen Sine
Published: May 2003

The influence of the different experimental parameters on the quality of the diffraction data collected on tetrafluoroterephthalonitrile (TFT) with a Nonius KappaCCD instrument has been examined. Data sets measured with different scan widths (0.25°, 0.50°, 1.0°) and scan times (70 s/° and 140 s/°) were compared with a highly redundant data set collected with an Enraf–Nonius CAD4 point detector diffractometer. As part of this analysis it was investigated how the parameters employed during the data reduction performed with theEvalCCDandSORTAVprograms affect the quality of the data. The KappaCCD data sets did not show any significant contamination from λ/2 radiation and possess good internal consistency with lowRintvalues. Decreasing the scan width seems to increase the standard uncertainties, which conversely are improved by an increase in the scan time. The suitability of the KappaCCD instrument to measure data to be used in charge density studies was also examined by performing a charge density data collection with the KappaCCD instrument. The same multipole model was used in the refinement of these data and of the CAD4 data. The two refinements gave almost identical parameters and residual electron densities. The topological analysis of the resulting static electron densities shows that the bond critical points have the same characteristics.
Diffuse scattering and short-range order in uranium iodine phthalocyanine [U1−x
Pc2]I2−y
and the X-ray structure analysis of crystals with diffuse superstructure reflections
Authors: Krawczyk J. , Pietraszko A. , Kubiak R. , Łukaszewicz K.
Published: May 2003

Crystals of uranium iodine phthalocyanine present an example of a disordered commensurate modulated structure of the intergrowth type. The short-range order of both uranium ions and iodine chains [I_3^-]
n
has been analysed by Reverse Monte Carlo (RMC) simulation of X-ray diffuse scattering. The diffraction pattern of uranium iodine phthalocyanine contains diffuse superstructure reflections. In the routine crystal structure analysis diffuse superstructure reflections may be either omitted or measured and classified along with other Bragg reflections. The crystal structure of uranium iodine phthalocyanine is an example of such ambiguity. The crystal structures of two specimens of [U1−x
Pc2]I2−y
with slightly different composition have been published in the literature with different space groups and unit cells. We have shown that the structure of both specimens differs only in the degree of short-range order and is isostructural with [YbPc2]I2. We have also shown that while the omission of diffuse reflections results in the average crystal structure, the treatment of these reflections as normal Bragg reflections is incorrect and produces the structure averaged over a limited small range.
Mechanism of the first-order phase transition of an acylurea derivative: observation of intermediate stages of transformation with a detailed temperature-resolved single-crystal diffraction method
Authors: Hashizume Daisuke , Miki Naoko , Yamazaki Toshiyuki , Aoyagi Yosuke , Arisato Tomokuni , Uchiyama Hiroki , Endo Tadashi , Yasui Masanori , Iwasaki Fujiko
Published: May 2003

The process of the first-order solid-to-solid phase transition of 1-ethyl-3-(4-methylpentanoyl)urea (1) was observed by means of a detailed temperature-resolved single-crystal diffraction method, which resembles watching a series of stop-motion photographs. The transition consists of two elementary processes, one supramolecular and the other molecular. Crystal structures from before and after the phase transition are isostructural. The straight-ribbon-like one-dimensional hydrogen-bonding structure is formed and stacked to form a molecular layer. The geometry of the layer is retained during the phase transition. The relative position of the layer with its neighbours, on the other hand, changes gradually with increasing temperature. The change is accelerated at the temperature representing the start of the endotherm seen in the DSC curves of (1). The structural variation yields void space between the neighbouring layers. When the void space grows enough that the crystal is unstable, the 3-methylbutyl group on the last of the molecules turns into a disordered structure with drastic conformational changes to fill up the void space. The phase transition process is well supported with simple force-field calculations. A crystal of 1-(4-methylpentanoyl)-3-propylurea (2), which shows no solid-to-solid phase transitions, was also analysed by the same method for comparison.
Experimental charge density in the transition metal complex Mn2(CO)10: a comparative study. Erratum
Authors: Farrugia Louis J. , Mallinson Paul R. , Stewart Brian
Published: May 2003

A value is missing in the third row of the O3—C3 section of Table 3 on p. 238 of Farrugia et al. (2003). The missing value which should be in the fifth column is 13.757, and the remaining entries should be transfered to the next column along.
Structure-forming components in crystals of ternary and quaternary 3d-metal complex fluorides
Authors: Peresypkina E. V. , Blatov V. A.
Published: May 2003

Crystallochemical analysis and classification were performed for 139 ternary and quaternary complex fluorides with the general formula M1
n

M2
m

M3F6, belonging to 33 structure types. Using coordination sequences and the uniformity criterion the structure-forming ionic sublattices or their combinations were found, which are responsible for the formation of stable periodic frameworks. Analysis of structure-forming motifs allows the interpretation of the crystal structures of complex fluorides as close packings of F ions with M1, M2 and M3 cations, partially occupying tetrahedral and octahedral voids, or as the packings of [M3F6] complex ions with M1 and M2 countercations in the voids. Cationic sublattices are noted to play an essential role, while forming crystal structures of complex fluorides. Relationships between the composition of structure-forming sublattices, the composition of compounds, and the size and charge of ions belonging to the sublattices were analysed under normal conditions, with thermal and high-pressure polymorphic transitions. Rules were formulated to predict the crystal structures of complex fluorides with a given chemical composition.
Structural changes of hexamethylenetetramine and undecanedioic acid co-crystal (HMT-C11) as a function of the temperature
Authors: Pinheiro Carlos Basílio , Gardon Manuel , Chapuis Gervais
Published: May 2003

HMT-C11 belongs to the family of adducts formed by the co-crystallization of N4(CH2)6 molecules (hexamethylenetetramine or HMT) and aliphatic dicarboxylic acids HOOC(CH2)
n − 2COOH with 5 ≤ n ≤ 13 (Cn). The adducts exhibit a layered structure in which the packing between HMT and Cn is determined by strong hydrogen bonds. The compounds in this family studied so far present thermotropic structural phase transitions and, depending on the chain length, disordered, twinned and modulated phases. The structure refinement of HMT-C11 based on X-ray diffraction experiments indicates three distinct phases from the melting point down to liquid nitrogen temperature: phase I is not crystalline; phase II is disordered (stacking fault) and its average structure is described in space group Bmmb; phase III is partially disordered and its symmetry is P21/c. The systematic study of the structure evolution of phase III upon cooling revealed that the disorder has a dynamic character (anharmonicity). The main structural change observed from 293 K down to 93 K is the increase of the tilting angle of the C11 chains relative to the layer plane and the rotation of the HMT molecules. Both HMT and C11 behave like rigid bodies in the temperature range investigated. The quality of the refinements leads to a conclusive model for the O—H...N hydrogen bonds linking HMT and C11.
Cation movement and phase transitions in KTP isostructures; X-ray study of sodium-doped KTP at 10.5 K
Authors: Norberg Stefan T. , Sobolev Alexander N. , Streltsov Victor A.
Published: May 2003

An accurate structure model of sodium-doped potassium titanyl phosphate, (Na0.114K0.886)K(TiO)2(PO4)2, has been determined at 10.5 K by single-crystal X-ray diffraction. In addition to the low-temperature data, X-ray intensities have been collected at room temperature. When the temperature was decreased from room temperature to 10.5 K, both potassium cations moved 0.033 (2) Å along the c-axis, i.e. in the polar direction within the rigid Ti—O—P network. This alkaline metal ion displacement can be related to the Abrahams–Jamieson–Kurtz T

C
criteria for oxygen framework ferroelectrics. Potassium titanyl phosphate (KTP) is a well known material for second harmonic generation (SHG), and the influence of sodium dopant on the TiO6 octahedral geometry and SHG is discussed. The material studied crystallizes in the space group Pna21 with Z = 4, a = 12.7919 (5), b = 6.3798 (4), c = 10.5880 (7) Å, V = 864.08 (9) Å3, T = 10.5 (3) K and R = 0.023.
Attitudes of the Croatian population toward genetically modified food
Authors: Renko Natasa , Brcic´‐Stipcevic´ Vesna
Published: May 2003

Until recently, the Croatian public has been relatively indifferent and unaware of issues related to genetically modified (GM) food products. However, the situation has changed and the Croatian public is becoming deeply sceptical about the benefits of GM food, and also generally about the food they eat. This paper examines some of the dimensions of the attitudes of the Croatian population toward GM food, and points out the high level of knowledge about biotechnology, and also the high level of non‐acceptance in this regard. These findings are significant for Croatian trade (especially importing and exporting), since knowledge about population preferences may influence the status of the Croatian food industry, as well as foreign food producers.
Food marketing in the function of tourist product development
Authors: Meler Marcel , Cerovic´ Zdenko
Published: May 2003

A tourist product should be observed as a total, i.e. integral, one, comprising material (goods) and immaterial (services) partial tourist products and partial tourist quasi‐products (being the results of a primary tourist offer that is not a result of human labor). The main idea of food marketing in foodstuff production, if observed as partial tourist products, implies that a guest, i.e. a tourist product consumer, is not only offered food and beverage as partial tourist products but that he also gets satisfied quantitatively, qualitatively, esthetically, ethnologically, gastronomically and in any other sense, including the accompanying immaterial partial tourist products, i.e. services, which will be eventually manifested in an increase in the room‐and‐board and, especially, secondary expenditures. Since the whole problem is analyzed using the example of the Republic of Croatia, simultaneously proposed are corresponding solutions in the field of food marketing that would be in the function of tourist product development.
A case study of the Croatian beer market structure and performances
Authors: Dumicic´ Ksenija , Renko Sanda , Renko Natasa
Published: May 2003

This paper considers the structure and performances of the Croatian beer market, as well as consumers’ attitudes and preferences. The results emphasise that the domestic brands with their quality and tradition, in spite of the imported beer brands’ influence, are the dominant brands on the Croatian beer market.
Farmers’ wine fair: a case study
Authors: Kovacic´ Damir , Radman Marija
Published: May 2003

The goal of this research is to empirically test one of the direct selling models – the farmers’ fair. We examined how the fairs can influence general recognition and improve the image of wines produced on family farms in Croatia, and how they affect the sales and number of the buyers at the family farms. Two surveys were carried out, one with fair’s visitors (n = 678) and the other with wine producers (n = 47). The research results confirmed usefulness of the organisation of the family farm wine fair on the Croatian market. The recognition of the family farm wine has increased and the image of these wines has improved on the local market. By participating at the wine fair the wine producers have enlarged the buyers tree and the wine sales at the farm.
The design and development of an online exhibition for heritage information awareness in Singapore
Authors: Chee Khoon Leong , Ramaiah Chennupati K. , Foo Schubert
Published: May 2003

Web‐based multimedia systems provide an exciting means and communication channel for information access and sharing, with immense potential in public education. In this study, a Web‐based multimedia exhibition was designed and developed based on an existing exhibition that took the original form of static physical displays, part of a series of National Education exhibitions put together by the National Archives of Singapore. A requirements gathering study was carried out with 77 university students to determine the users’ requirements in terms of their computer and Web experience, content expectations of an online exhibition and their prior exposure to these systems. A prototype of an online exhibition system was developed and then evaluated by 30 of the students. They felt the online exhibition satisfied most of their requirements, apart from a search engine, and that online exhibitions were a flexible mode of delivering heritage information to inculcate awareness among the public, particularly in the context of Singapore, with its high percentage of Internet users.
ELFNI (Electronic Libraries for Northern Ireland project): an overview
Authors: Frawley Rosemary
Published: May 2003

The Electronic Libraries for Northern Ireland project (ELFNI) was established to procure on behalf of the five Northern Ireland Education and Library Boards (NIELBs) robust systems that would support and enable the delivery of electronic information services to the Northern Ireland (NI) community and to enable the NIELBs to deliver cost effective, efficient and modern public library and information services. Following a period of discussion and negotiation a Public Finance Initiative (PFI) contract was signed in early 2002 between Amey BPO Services and the five Education and Library boards for the ELFNI project. Amey BPO will lead a consortium which will be responsible for delivering a range of services to all public libraries in Northern Ireland for the next ten years, which includes the installation of the People’s Network, a single library management system, a libraries’ portal, video‐conferencing facilities and corporate e‐mail for all staff. This paper provides a background to the development of this project, details of the technological solution, information on the monitoring procedures, a description of the expected benefits from the ELFNI system and concludes with an assessment of PFI funding for public libraries.
Implementing the first library management system at Merthyr Tydfil Public Libraries: an overview and impact on staff
Authors: Mitchell Vicky
Published: May 2003

Merthyr Tydfil Public Libraries, the smallest public library authority in England and Wales, has introduced its first library management system at the same time as the People’s Network. The paper describes the process of selecting and implementing the final chosen system from Talis Information. In addition, the impact on staff who have had to change their working practices in a very short space of time is described.
Development of ICT for library and information professionals: a training package for developing countries in Asia and Pacific from Unesco
Authors: Ornager Susanne
Published: May 2003

This short communication describes the development, by Unesco, of a package of six ICT‐related modules that have been designed to be used in “face‐to‐face” week‐long training courses for library and information professionals in South East Asia. The modules are freely available for use.
The requirements of ethical fund managers and property investment
Authors: Ross Jayne Michael , Skerratt Glynn
Published: May 2003

Ethical and environmental investment criteria, now known as socially responsible investment (SRI), are increasingly commonplace in the market today. Some investors have specifically set themselves up as ethical investors. Consequently, ethical considerations are a cornerstone of their investment policy. Many of the funding institutions have ethical investment arms, even where these are not their mainstream activity. Understanding the role of ethical investors, and their ethical considerations, within the property market would appear, therefore, to be of increasing importance to the property professions. The activities of funding institutions specifically marketing themselves as ethical and those not so doing are explored, using an in‐depth questionnaire, in order to determine what these environmental criteria are and the way in which they are considered. The results are placed in the context of property and property investment. It is concluded that a knowledge of ethical issues is advantageous for property professionals, especially when advising ethical investor clients.
A conceptual framework to measure facilities management performance
Authors: Amaratunga Dilanthi , Baldry David
Published: May 2003

This paper concerns the measurement of facilities management performance. Empirical research carried out indicates that facilities management appears to utilise a wide range of measures – not only traditional financial accounting measures, but also indicators of managerial behaviour as well as various other measures of effectiveness. Considers the basis for measurement of performance in facilities management with reference to a conceptual framework identified by taking into consideration the advantages and some of the drawbacks with current performance measurement systems.
A study of the factors influencing the operating location decisions of small firms
Authors: Mazzarol Tim , Choo Stephen
Published: May 2003

Investigates the purchase of industrial real estate by small to medium enterprises. Using a three‐stage methodology, examined the views of a stakeholder panel, then drew a sample of 450 firms ranging from micro‐businesses to large firms and examined the importance of various factors likely to influence the attractiveness of an industrial site. A focus group comprising members of an expert panel was then convened to discuss the findings. Highlights the subjective decision‐making associated with the smaller firms in comparison with the “buying centre” objectivity of the larger firms. Owner‐managers from micro and small firms were motivated by such personal issues as the proximity of the industrial site to their home, rather than access to transport routes or freight terminals. The findings suggest that government and private sector agencies seeking to develop and market industrial land need to devote more time to understanding the needs of small firms. Also discusses implications for future research.
Misplaced marketing: Who do you hire when the advertising audience isn’t you?
Authors: Rotfeld Herbert Jack
Published: May 2003

Focuses on the importance of marketing from the customers’ point of view when the target markets are in different demographic groups from those of the advertising agencies’ staff or marketing managers. States that mass communications work must take place within a context of understanding the target audiences’ subcultures; understanding does not require membership of those subcultures, but it does require empathy with them.