bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of humic substances by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Mugo Samuel M. , Bottaro Christina S.
Published: September 2004

Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) and laser desorption/ionization (LDI‐)TOFMS have been used to characterize Suwannee River humic substances, obtained from the International Humic Substances Society (IHSS), and Armadale soil fulvic acid (ASFA). An array of MALDI matrices were tested for use with humic substances, including α‐cyano‐4‐hydroxycinammic acid (CHCA), 2‐(4‐hydroxyphenylazo)benzoic acid (HABA), 2,5‐dihydroxybenzoic acid (DHBA), sinapinic acid, dithranol and norharmane. DHBA yielded the best results, exhibiting superior ionization efficiency, low noise, broad applicability to the analytes of interest, and most importantly producing an abundance of high mass ions, the highest observed being m/z 1848. A number of sample preparation modes were investigated; the overlayer method improved sample/matrix homogeneity and hence shot‐to‐shot reproducibility. The choice of the matrix, mass ratio of analyte to matrix, and the sample preparation protocol, were found to be the most critical factors governing the quality of the mass spectra. Matrix suppression was greatly enhanced by ensuring good mixing of matrix and analyte in the solid phase, proper optimization of the matrix/analyte ratio, and optimizing delayed extraction to ensure complete matrix–analyte reaction in the plume before ions are moved to the flight tube. A number of common features, in particular specific ions which could not be attributed to the matrices or to contaminants, were present in the spectra of all the humic substances, regardless of origin or operational definition. Additionally, a prominent repeating pattern of peaks separated by 55, 114 and 169 Da was clearly observed in both LDI and MALDI, suggesting that the humic compounds studied here may have quasi‐polymeric or oligomeric features. Copyright © 2004 John Wiley & Sons, Ltd.
Online measurement of rheological properties of PVC/wood‐flour composites
Authors: Shah Bhavesh L. , Matuana Laurent M.
Published: September 2004

By using a factorial design approach, this study examined the effect of the component materials on the viscoelastic properties of PVC/wood‐flour composites. Statistical analysis was performed to determine the effects of wood‐flour content, acrylic modifier content, and plasticizer content on the die swell ratio and viscosity of the composites measured online on a conical twin‐screw extrusion capillary rheometer. The viscoelastic properties of the samples also were measured using dynamic mechanical analyzer (DMA). Wood‐flour content and acrylic modifier content were the two important variables affecting the die swell ratio, whereas the addition of a low level of plasticizer did not affect this ratio. The die swell increased with the increased acrylic modifier content, but it was reduced considerably by adding wood flour into the PVC matrix. The true viscosity of neat PVC and PVC/wood‐flour composites decreased with the plasticizer content, irrespective of the acrylic modifier content. However, the addition of acrylic modifier significantly increased the viscosity of unfilled PVC, while an opposite trend was observed for the composites, owing to the differing effect of acrylic modifier on the melt elasticity and viscosity of these materials. J. Vinyl Addit. Technol. 10:121–128, 2004. © 2004 Society of Plastics Engineers.
Performance benefits of TPE inter‐material substitution using metallocene ethylene elastomers
Authors: Weaver Laura B. , Vercuski Phil , Waszeciak Doug
Published: September 2004

Thermoplastic elastomers (TPEs) are one of the fastest‐growing segments of the plastic compounding market and are projected to grow at an annual rate of 5%–6% (1). By offering additional options and benefits on the price‐performance curve, thermoplastic olefins (TPOs) are expected to grow at higher rates than many styrenics and thermoplastic vulcanizates (TPVs) in automotive, durables and construction market sectors. Traditionally, these markets initially specify materials that may be over‐engineered in an application to ensure they fully meet the required properties. Over time, however, specifiers are often forced to shift their focus to reduce costs via new material substitution, provided they can continue to meet the required properties. Likewise, inter‐material substitution is a common trend based on the product delivering improved performance over the incumbent material at comparable costs, such as the movement to replace f‐PVC compounds with soft TPOs in automotive interior thermoformed sheeting. The soft TPOs based on metallocene ethylene elastomers offer improved cold‐temperature‐impact performance, lower part weight, and extended lifetime durability over f‐PVC at essentially the same part cost. This paper offers a comparison of emerging soft TPO compounds based on metallocene ethylene elastomers with styrene tri‐block polymer (SEBS), TPVs and f‐PVC compounds. J. Vinyl Addit. Technol. 10:129–136, 2004. © 2004 Society of Plastics Engineers.
Layout and first XRF applications of the BAMline at BESSY II
Authors: Riesemeier H. , Ecker K. , Görner W. , Müller B.R. , Radtke M. , Krumrey M.
Published: September 2004

The first hard x‐ray beamline at BESSY II has been installed by BAM and PTB at a superconducting 7 T wavelength shifter. The main optical elements of the beamline are a double‐multilayer monochromator and a double‐crystal monochromator. Depending on the application, the two devices are used separately or in‐line. The main applications of the monochromatic radiation with photon energies up to 60 keV are x‐ray fluorescence analysis, micro computed tomography, x‐ray topography, detector calibration and reflectometry. Calculable undispersed radiation up to 200 keV is available for radiometric applications. Copyright © 2004 John Wiley & Sons, Ltd.
The role of teacher relationships in the lives of students
Authors: Fredriksen Katia , Rhodes Jean
Published: September 2004

Positive teacher‐student relationships are seen through a variety of psychological models.
Effects of pulsed versus conventional radiofrequency current on rabbit dorsal root ganglion morphology
Authors: Erdine Serdar , Yucel Aysen , Cimen Ali , Aydin Salih , Sav Aydin , Bilir Ayhan
Published: September 2004

Lesioning using radiofrequency (RF) current has been increasingly used in clinical practice for the treatment of pain syndromes. Although formation of heat causing “thermocoagulation” of the nervous tissues is thought to be responsible of the clinical outcome, a more recent modality of RF application named pulsed radiofrequency (PRF) delivers the RF current without producing destructive levels of heat. In our study, we compared the effects of conventional RF (CRF) and PRF on rabbit dorsal root ganglion (DRG) morphology, including also control and sham operated groups. The setting of the experiment and the RF parameters used were similar to those used in current clinical practice. The specimens were analyzed both with light microscopy and electron microscopy, two weeks after the procedure. At the light microscopic level, all groups had preserved the normal DRG morphology and no differences were observed between them. In the electron microscopic analysis there were no pathological findings in the control and sham operated groups. But the ganglion cells in the RF groups had enlarged endoplasmic reticulum cisterns and increased number of cytoplasmic vacuoles which were more evident in the CRF group. Some of the ganglion cells in the CRF group had mitochondrial degeneration, nuclear membrane disorders or loss of nuclear membrane and neurolemma integrity. The myelinated and unmyelinated nerve fibers were of normal morphology in all groups. Our results suggest that PRF application is less destructive of cellular morphology than CRF at clinically used “doses”. Before making certain judgements, more experimental and clinical studies should be planned.
The erythrocyte skeletons of β‐adducin deficient mice have altered levels of tropomyosin, tropomodulin and EcapZ
Authors: Porro Fabiola , Costessi Luisa , Marro Martı́n L. , Baralle Francisco E. , Muro Andrés F.
Published: September 2004

The erythrocyte membrane cytoskeleton is organized as a polygonal spectrin network linked to short actin filaments that are capped by adducin at the barbed ends. We have constructed a mouse strain deficient in β‐adducin having abnormal erythrocytes. We show here that the levels of several skeletal proteins from β‐adducin mutant erythrocytes are altered. In fact, CapZ, the main muscle actin‐capping protein of the barbed ends that in the erythrocytes is cytoplasmic, is 9‐fold upregulated in mutant skeletons of erythrocytes suggesting a compensatory mechanism. We also detected upregulation of tropomodulin and downregulation of α‐tropomyosin and actin. In addition, purified adducin can be re‐incorporated into adducin‐deficient ghosts.
Distance dependence of interactions between charged centres in proteins with common structural features
Authors: Louro Ricardo O. , Catarino Teresa , Paquete Catarina M. , Turner David L.
Published: September 2004

Data collected for interactions among redox centres, and interactions between redox centres and acid–base residues in a family of small multihaem cytochromes are analysed. The distance dependent attenuation of the interactions between non‐surface charges, for separations that range from 8 to 23 Å, can be described by a simple function derived from the Debye–Hückel formalism, fit to 9.5 and 7.6 as values for the relative dielectric constant and Debye length, respectively. However, there is considerable scatter in the data despite the structural similarities among the proteins, which is discussed in the framework of using such simple models in predicting properties of novel proteins.
Overproduction of CcmABCDEFGH restores cytochrome c maturation in a DsbD deletion strain of E. coli: another route for reductant?
Authors: Stevens Julie M. , Gordon Euan H. , Ferguson Stuart J.
Published: September 2004

The multidomain transmembrane protein DsbD is essential for cytochrome c maturation (Ccm) in Escherichia coli and transports reductant to the otherwise oxidising environment of the bacterial periplasm. The Ccm proteins ABCDEFGH are also essential and we show that the overproduction of these proteins can unexpectedly complement for the absence of DsbD in a deletion strain by partially restoring the production of an exogenous c‐type cytochrome under aerobic and anaerobic conditions. This suggests that one or more of the Ccm proteins can provide reductant to the periplasm. The Ccm proteins do not, however, restore the normal disulfide mis‐isomerisation phenotype of the deletion strain, as shown by assay of the multidisulfide‐bonded enzyme urokinase.
Population genetic structure of the kuruma prawn (Penaeus japonicus) in East Asia inferred from mitochondrial DNA sequences
Authors: Tzeng Tzong-Der , Yeh Shean-Yeh , Hui Cho-Fat
Published: September 2004

Sequence analyses on the complete mitochondrial DNA (mtDNA) control region (992 bp) were conducted to elucidate the population structure of kuruma prawns (Penaeus japonicus) in East Asia. Five populations including 95 individuals were collected. They are separated into the Japan Sea (JS), the north and south of the East China Sea (NECS and SECS), the Taiwan Strait (TS), and the north of the South China Sea (NSCS) populations. There are 292 variable sites without any insertions and deletions. Nucleotide diversity in the total populations is 2.51 ± 0.07%, and the variations within populations ranged from 2.61 ± 0.93% (SECS) to 2.29 ± 0.16% (JS). FST values between the JS and the rest of the populations, between the NECS and NSCS populations, and between the SECS and NSCS populations show significant differences. The UPGMA tree of these five populations shows three distinct clusters; one includes the JS population; another includes the NECS population; the third includes populations from the rest of the areas. The analysis of molecular variance (AMOVA) shows clear genetic difference between the JS and the rest of the populations. Additional AMOVA analysis excluding the JS population indicates significant variation between the NECS population and the other three populations. We, therefore, conclude that three distinct populations exist in East Asia; one is in the JS; another is in the NECS; and the third is distributed in SECS, TS and NSCS.
At-sea distribution of female southern elephant seals relative to variation in ocean surface properties
Authors: Bradshaw Corey J.A. , Higgins Jane , Michael Kelvin J. , Wotherspoon Simon J. , Hindell Mark A.
Published: September 2004

We examined the relationships between physical oceanography (sea surface temperature – SST, sea surface height anomaly – SSH, ocean colour – OC, bathymetry – BA, sea-ice concentration – SI, and their associated gradients) and the foraging distribution (time at sea) of female southern elephant seals using generalized linear and generalized additive models (GLM and GAM). Using data from 28 separate foraging trips (22 unique individuals) over two years, we found that during the post-lactation trips (summer), the best GLM demonstrated a negative relationship between time at sea and SST and BA, but a positive relationship with SST gradient and SSH. During the post-moult (winter) trips, there was a negative relationship with OC gradient, SSH, and BA. The best post-lactation GAM identified a positive relationship with OC gradient, negative relationships with OC and SST gradient, and a non-linear relationship with SST. For the post-moult trip there was a negative relationship with OC, SST, BA and BA gradient, and a positive relationship with SST gradient. The relationship between the predicted time and observed time at sea was significant only for the post-lactation GAM, although predictability was low. That SST and its gradient predicted a small, but significant proportion of the variation in time at sea is indicative of the frontal zones within this area that are generally more biologically productive than surrounding regions. It appears that coarse-scale oceanographic configuration influences foraging behaviour in southern elephant seals only subtly. Nonetheless, some of the mechanisms influencing predator foraging are congruent with expectations of distribution of marine food resources at coarse spatial scales.
Neurodegeneration and plasticity
Authors: Arendt Thomas
Published: September 2004

Neurofibrillary degeneration, associated with the formation of paired helical filaments (PHF), is one of the critical neuropathological hallmarks of Alzheimer's disease (AD). Although the microtubule‐associated protein tau in a hyperphosphorylated form has been established as primary PHF constituent, the process of tau phosphorylation and its potential link to degeneration is not very well understood, mostly because of the lack of a physiological in vivo model of PHF‐like tau phosphorylation. PHF formation in AD follows a hierarchial pattern of development throughout different cortical areas, which closely matches the pattern of neuronal plasticity in the adult brain. Those brain areas are most early and most severely affected which are involved in the regulation of memory, learning, perception, self‐awareness, consciousness, and higher brain functions that require a life‐long re‐fitting of connectivity, a process based on a particularly high degree of plasticity. Failures of synaptic plasticity are, thus, assumed to represent early events in the course of AD that eventually lead to alteration of tau phosphorylation. Recently, we have used the hibernation cycle, a physiological model of adaptation associated with an extraordinary high degree of structural neuronal plasticity, to analyze the potential link between synaptic plasticity, synaptic detachment and the regulation of tau phosphorylation. During torpor, a natural state of hypothermia, synaptic contacts between mossy fibers and hippocampal pyramidal neurons undergo dramatic regressive changes that are fully reversible very rapidly during euthermy. This rapid, reversible, and repeated regression of synaptic and dendritic components on CA3 neurons is associated with a reversible PHF‐like phosphorylation of tau at a similar time course. The repeated formation and degradation of PHF‐tau might, thus, represent a physiological mechanism not necessarily associated with pathological effects. These findings implicate an essential link between neuronal plasticity and PHF‐like phosphorylation of tau, potentially involved in neurofibrillary degeneration.
Purinergic modulation of extracellular glutamate levels in the nucleus accumbens in vivo
Authors: Krügel Ute , Schraft Thomas , Regenthal Ralph , Illes Peter , Kittner Holger
Published: September 2004

In the present study, the P2 receptor‐mediated modulation of the extracellular glutamate concentration was investigated by microdialysis in the nucleus accumbens (NAc) of freely moving rats. Because of the known interference of dopaminergic and glutamatergic mechanisms in this area the experiments were performed with animals intra‐accumbally treated with 6‐hydroxydopamine (6‐OHDA) to deplete dopamine pools. Perfusion of the NAc with the prototypic P2 receptor agonist 2‐methylthioadenosine 5′‐triphosphate (2‐MeSATP, 0.1, 1 and 10 mM) concentration‐dependently increased the extracellular level of glutamate in this area. Pretreatment with the P2 receptor antagonist pyridoxalphosphate‐6‐azophenyl‐2′,4′‐disulphonic acid (PPADS, 0.1 mM) decreased the basal extracellular glutamate concentration and inhibited the 2‐MeSATP‐induced outflow of glutamate. In rats treated with 6‐OHDA, 2‐MeSATP increased the total extracellular glutamate to an extent about fivefold larger than in sham‐lesioned rats. The perfusion of the dopamine‐depleted NAc with the D2/D3 dopamine receptor agonist quinpirole (0.1 mM) diminished the basal concentration of glutamate and reduced the effect of 2‐MeSATP on the extracellular glutamate.

These results provide evidence that the stimulation of P2 receptors is involved in the increase of accumbal extracellular glutamate in vivo. This behaviourally relevant mechanism depends on a dopamine D2 receptor‐mediated tone in the nucleus accumbens. Furthermore, the inhibition of P2 receptors may prevent, at least partly, glutamate‐mediated neurodegeneration.
Expression of cell cycle‐related proteins in developing and adult mouse hippocampus
Authors: Schmetsdorf Stefanie , Gärtner Ulrich , Arendt Thomas
Published: September 2004

Developmental structuring of brain is the result of a strictly coordinated process that involves controlled cell division, neuronal migration and terminal differentiation. Neurogenesis occurs generally during embryonic and early postnatal stages and will be finished in the mature brain. Once differentiated, neurons are incapable of further division but retain the capability of structural and functional plasticity. However, there are distinct regions in the adult brain of mammals that generate neurons continuously throughout life. Among them, the hippocampus, which is known as a region with a high degree of neuroplasticity, is of particular interest in the context of adult neurogenesis.

In general, progression through cell cycle phases is regulated by the sequential expression and activation of regulatory proteins like cyclin dependent kinases (cdk), cyclins, or cdk inhibitors (cdki). In postmitotic and terminally differentiated neurons, cell cycle activity is arrested by enrichment of cdkis. The timing of cell cycle exit and neuronal differentiation is likely to be regulated in part by cell cycle regulatory proteins. However, the expression of cell cycle markers in the postnatal or adult brain is still a matter of controversial debate. In the present study, we examined the expression of cdks, cyclins and cdkis within the mouse hippocampus at different developmental stages (embryonic days 17, 19; postnatal day 11 and adult) using immunohistochemical methods. During the prenatal development, cell cycle proteins were localized predominantly in nuclei of all presumptive neuronal populations but expression was not restricted to proliferative cells. With developmental progression, the subcellular localization of most markers was increasingly shifted from nuclear to the cytoplasmic compartment. However, even in the adult, cell cycle‐related proteins were found in terminally differentiated pyramidal and granule neurons. Here, they were mainly localized in the perikaryal cytoplasm but only sporadically in neuronal nuclei. Occasionally, immunoreactivity was also found in dendrites and mossy fibers. The present results suggest that cell cycle arrest and terminal differentiation is not necessarily incompatible with the expression of cell cycle‐related markers. Thus, they may have supplementary functions in differentiated neurons that might be associated with neuronal plasticity.
Tension in a double loop tendon anterior cruciate graft during a simulated open chain knee extension exercise
Authors: Karchin Ari , Hull M. L. , Howell S. M.
Published: September 2004

Concerns exist regarding the tension developed in a reconstructed anterior cruciate ligament (ACL) during open chain knee extension exercises used to rehabilitate the knee. Therefore, the primary objective was to measure tension in an ACL graft during a simulated open chain knee extension exercise as a function of ankle weight. A secondary objective was to determine whether the graft tension was reduced with relatively high stiffness fixation. The open chain exercise was simulated in seven cadaveric specimens in which the ACL had been reconstructed with double loop tendon grafts. Graft tension was measured at 15° of flexion as the effective ankle weight was increased from 22.5 to 67.5 and then to 112.5 N for three different fixation stiffnesses (25, 125, and 225 N/mm). The initial tension was set to restore the 225 N anterior limit of motion to that of the intact knee at 30° of flexion. Increasing the ankle weight caused the graft tension to increase significantly (p < 0.0001), but the increase with the highest ankle weight was only 62 N on average. Increasing the fixation stiffness caused the graft tension to decrease significantly (p < 0.0001) because the initial tension decreased by 107 N as the fixation stiffness increased. Because the graft tension with the highest ankle weight was limited to 112 N on average, high stiffness fixation methods, which are also resistant to lengthening in the region of the fixation, may reduce the risk of graft construct lengthening during open chain knee extension exercises. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Nasal Colonization with Staphylococcus Aureus is not Associated with the Severity of Symptoms or the Extent of the Disease in Chronic Rhinosinusitis
Authors: Damm Michael , Quante Gero , Jurk Thorsten , Sauer Jan Alex
Published: September 2004

OBJECTIVES

There is an increasing knowledge that the severity of perennial allergic rhinitis is associated with nasal carriage of Staphylococcus aureus (S. aureus). The aim of this study was to evaluate the rate of bacterial colonization with S. aureus in the nose of subjects with and without chronic rhinosinusitis (CRS) and to correlate these findings with the severity of symptoms and the extent of the disease.

STUDY DESIGN AND SETTING

Open, prospective controlled trial.

METHODS

190 subjects with CRS and 42 subjects with septal deviation without sinusitis (control subjects) were included in this study. Swabs were taken endoscopically from the middle meatus and bacteria were cultured and identified. Airway symptoms were assessed by subjects in standardized questionnaires and frequencies of respiratory tract infections were noted. The rhinosinusitis extent was graded by CT scan assessment. Analysis of variance, chi‐square test, and Pearson's correlation test were applied for statistical analyses.

RESULTS

The S. aureus carriage rate was 25.5% in CRS and 31.4% in control subjects. Further facultative pathogens were cultured in 20.6% of subjects with CRS and in 8.5% of controls. 73.8% of S. aureus were ampicillin‐resistant, multiresistant strains were cultured in 5.8%. Most airway symptoms and the frequencies of respiratory tract infections were significantly higher in the CRS group compared with control subjects. In post hoc comparison between the subgroups with and without S. aureus colonization, no significant differences were found between the extent of rhinosinusitis and the severity of airway symptoms.

CONCLUSIONS

Facultative pathogens were detected in more than 40% of CRS patients without acute respiratory tract infections. In contrast to the findings in atopic dermatitis and perennial allergic rhinitis, the colonization rate with S. aureus is not increased and S. aureus carriage is not a risk factor for the severity or the extent of rhinosinusitis.
Tree-ring growth curves as sources of climatic information
Authors: Naurzbaev Mukhtar M. , Hughes Malcolm K. , Vaganov Eugene A.
Published: September 2004

Regional growth curves (RGCs) have been recently used to provide a new basis for removing nonclimatic trend from tree-ring data. Here we propose a different use for RGCs and explore their properties along two transects, one meridional and the other elevational. RGCs consisting of mean ring width plotted against cambial age were developed for larch samples from 34 sites along a meridional transect (55–72°N) in central Siberia, and for 24 sites on an elevational gradient (1120 and 2350 m a.s.l.) in Tuva and neighboring Mongolia at approximately 51°N. There are systematic gradients of the parameters of the RGCs, such as I0-maximum tree-ring width near pith, and Imin, the asymptotic value of tree-ring width in old trees. They are smaller at higher latitude and elevation. Annual mean temperature and mean May–September temperature are highly correlated with latitude here, and hence RGC parameters are correlated with these climatic variables. Correlations with precipitation are more complex, and contradictory between meridional and elevational transects. The presence of a similar gradient in the elevational transect is consistent with temperature being the causal factor for both gradients, rather than, for example, latitude-dependent patterns of seasonal photoperiod change. Taking ring measurements from collections of relict and subfossil wood, the RGC–latitude and RGC–temperature relationships are used to estimate paleo-temperatures on centennial time scales. These estimates are consistent with earlier "traditional" dendroclimatic approaches, and with independent information on the northern extent of forest growth in the early mid-Holocene. It may be possible to use this same approach to make estimates of century-scale paleo-temperatures in other regions where abundant relict wood is present.
Late Quaternary downcutting rates of the Qianyou river from U/Th speleothem Dates, Qinling mountains, China
Authors: Fei Wang , Hongchun Li , Rixiang Zhu , Feizhou Qin
Published: September 2004

Dating deposits in caves formed by rivers may yield insight into rates and processes of bedrock incision. Three cave passages at different levels have developed in the walls of the Qianyou River valley in the Qinling mountains, south of the city of Xian, China. Twelve speleothem samples near the position of palaeowater tables in three cave passages are dated by the 230Th dating method. The results show that the river cut down at the rate of 0.23 ± 0.02 mm/yr from 358,000 ± 38,000 to 247,000 ± 28,000 yr ago, 0.19 ± 0.03 mm/yr from 247,000 ± 28,000 to 118,000 ± 19,000 yr ago, and 0.51 ± 0.08 mm/yr from 118,000 ± 19,000 yr ago until today. These fall very close to the glacial–interglacial transition following marine oxygen isotope stages 10, 8, and 6, respectively. The increase in downcutting rates during the interglacial period is consistent with warm, wet weather, increasing rates of erosion. This may lead us toward an underlying mechanism for modulating incision that is not in a direct response to the presence of headwater glaciers.
Sediment-magnetic signature of land-use and drought as recorded in lake sediment from south-central Minnesota, USA
Authors: Geiss Christoph E. , Banerjee Subir K. , Camill Phil , Umbanhowar Charles E.
Published: September 2004

Sediment magnetic properties of a short core from Sharkey Lake, MN, record the effects of Euroamerican settlement and climate change over the last 150 yr. The onset of European-style farming led to increased erosion, reflected in high values of concentration-dependent parameters such as magnetic susceptibility (ĸ), Isothermal Remanent Magnetization (IRM), and Anhysteretic Remanent Magnetization (ARM). These high values are only partially due to increased supply of terrigenous material to the lake, and recent sediment contains an additional component of authigenic fine (single-domain) magnetite, most likely magnetosomes from magnetotactic bacteria. High organic productivity in the lake during the 1920s to 1940s drought increased this authigenic component resulting in highly magnetic fine-grained sediment. A comparison with older Holocene sediment from the same lake shows that, over time, most of the fine magnetic signal is lost after deposition, leading to decreases in magnetization and a bimodal grain size distribution of ultrafine, superparamagnetic grains and coarser multidomain particles, evident from measurements of ARM/IRM ratios, hysteresis measurements, and low-temperature analyses. The effects of dissolution and the superposition of climate and land-use signals complicate the use of recent sediments as modern analogs for sediment magnetic analyses.
Mechanism of Block of hEag1 K+ Channels by Imipramine and Astemizole
Authors: García-Ferreiro Rafael E. , Kerschensteiner Daniel , Major Felix , Monje Francisco , Stühmer Walter , Pardo Luis A.
Published: September 2004

Ether à go-go (Eag; KV10.1) voltage-gated K+ channels have been detected in cancer cell lines of diverse origin and shown to influence their rate of proliferation. The tricyclic antidepressant imipramine and the antihistamine astemizole inhibit the current through Eag1 channels and reduce the proliferation of cancer cells. Here we describe the mechanism by which both drugs block human Eag1 (hEag1) channels. Even if both drugs differ in their affinity for hEag1 channels (IC50s are ∼2 μM for imipramine and ∼200 nM for astemizole) and in their blocking kinetics, both drugs permeate the membrane and inhibit the hEag1 current by selectively binding to open channels. Furthermore, both drugs are weak bases and the IC50s depend on both internal an external pH, suggesting that both substances cross the membrane in their uncharged form and act from inside the cell in their charged forms. Accordingly, the block by imipramine is voltage dependent and antagonized by intracellular TEA, consistent with imipramine binding in its charged form to a site located close to the inner end of the selectivity filter. Using inside- and outside-out patch recordings, we found that a permanently charged, quaternary derivative of imipramine (N-methyl-imipramine) only blocks channels from the intracellular side of the membrane. In contrast, the block by astemizole is voltage independent. However, as astemizole competes with imipramine and intracellular TEA for binding to the channel, it is proposed to interact with an overlapping intracellular binding site. The significance of these findings, in the context of structure–function of channels of the eag family is discussed.
Ilf3 and NF90 associate with the axonal targeting element of Tau mRNA
Authors: Larcher Jean-Christophe , Gasmi Laila , Viranaïcken Wildriss , Eddé Bernard , Bernard Rozenn , Ginzburg Irith , Denoulet Philippe
Published: September 2004

In neurons, the selective translocation of Tau mRNA toward axons is due to the presence of a nucleotide sequence located in its 3′ untranslated region and serving as axonal targeting element. Using this RNA sequence as a probe by a Northwestern approach, we have detected several proteins that interact with the targeting RNA element and could potentially be involved in Tau mRNA translocation, translation halting, and/or stabilization. Among them, two proteins were identified as the interleukin enhancer binding factor 3 (Ilf3) and NF90, two isoforms derived from a single gene product through alternative splicing. Each protein comprises two double‐stranded RNA binding motifs that can interact with the predicted stem‐loop secondary structure of the axonal targeting element. Specific antibodies raised against common or specific peptide sequences showed that both Ilf3 and NF90 are polymorphic proteins that are detected in neuronal nuclei and cell bodies, as well as in the proximal neuritic segments. This observation favors the idea that Ilf3 and NF90 are part of a protein complex that escorts Tau mRNA toward the axon.
Identification of Mammalian microRNA Host Genes and Transcription Units
Authors: Rodriguez Antony , Griffiths-Jones Sam , Ashurst Jennifer L. , Bradley Allan
Published: September 2004

To derive a global perspective on the transcription of microRNAs (miRNAs) in mammals, we annotated the genomic position and context of this class of noncoding RNAs (ncRNAs) in the human and mouse genomes. Of the 232 known mammalian miRNAs, we found that 161 overlap with 123 defined transcription units (TUs). We identified miRNAs within introns of 90 protein-coding genes with a broad spectrum of molecular functions, and in both introns and exons of 66 mRNA-like noncoding RNAs (mlncRNAs). In addition, novel families of miRNAs based on host gene identity were identified. The transcription patterns of all miRNA host genes were curated from a variety of sources illustrating spatial, temporal, and physiological regulation of miRNA expression. These findings strongly suggest that miRNAs are transcribed in parallel with their host transcripts, and that the two different transcription classes of miRNAs (`exonic' and `intronic') identified here may require slightly different mechanisms of biogenesis.
Information for Scotland 1993‐1998: a review
Authors: Newton Robert , Dixon David
Published: September 2004

Reviews the issues arising out of an annual series of conferences, Information for Scotland, held since 1993. Three main contexts are identified and issues examined: marketisation and globalisation, convergence and regrouping, the Scottish Parliament and democratic renewal within the political context; the new agenda for learning within education; and the rise of electronic networks within technological change, are all discussed in the context of papers delivered at the conferences.
Practitioners as educators: formal quality assessment of the Bristol MSc in Information and Library Management
Authors: Heery Mike
Published: September 2004

This article updates a more substantial article published in Library Review in 1999. The earlier article describes an LIS school based in the University of Bristol. The school runs an MSc in Information and Library Management which is unique in the UK as it is taught by practising LIS professionals. The present article reports on recent quality assessment of the MSc by the Quality Assurance Agency for Higher Education. This quality assessment awarded the course the highest possible marks and the article explains why the course received such a strong endorsement.
A cross‐cultural comparison of style in Eastern European emerging markets
Authors: Manrai Lalita A. , Lascu Dana‐Nicoleta , Manrai Ajay K. , Babb Harold W.
Published: September 2004

Torn between socially‐mandated dress conformity and the glitter of Western designers, consumers in Eastern Europe have always been interested in Western style. After the fall of Communism, fashion, led by Western brands, quickly conquered consumers, while local manufacturers started to offer quality goods. Exposure to Western brands and advertising affected consumer values: former collectivist values are gradually being replaced by individualism. These changes are occurring at different rates and vary in different market segments. Under these conditions, a study was conducted in Bulgaria, Hungary and Romania, comparing respondents on two dimensions of style: fashion‐consciousness (capturing individualism) and dress‐conformity (capturing collectivism). The findings support the hypothesis that fashion consciousness is highest for Westernized Hungarian respondents, who have the highest income and can afford fashionable clothing. Dress conformity was highest for Bulgarian respondents, who had setbacks in adopting a market economy and are less Westernized. The findings support demographic differences predictions: younger individuals are more fashion conscious than older individuals, whereas dress conformity is higher for older than for younger individuals. Finally, men are more fashion conscious than women. The findings on gender differences in dress conformity are mixed. Marketing implications of these findings and future research directions are discussed.
Export promotion organization emergence and development: a call to research
Authors: Gillespie Kate , Riddle Liesl
Published: September 2004

Most existing research examines export promotion organization (EPO) performance by assessing how firms benefit from their awareness, perceptions and use of EPO services. Remarkably, few studies examine how EPOs decide which services they will offer. This paper is presented as a call for further research to better understand how and why EPOs determine, deliver and amend their service offerings. This paper first reviews the EPO literature linking EPO service offering to firm awareness, perceptions and use of EPO services, all of which ultimately impact firm performance. Next, it is proposed that both macro‐ and micro‐level approaches derived from the organizational studies literature can be used to explore more fruitfully the effect of EPO genesis and change on EPO services. Each approach is followed by a brief illustrative example. In conclusion suggestions for further research, proposed methodologies, and a discussion of the policy implications of this line of inquiry are presented.
Commercial applications of digital printing technologies on PCBs
Authors: Fritz Hans
Published: September 2004

The PCB industry is quickly gearing up for the digital printing age. While photo imaging and screen‐printing have been commonly used as recognized and established techniques in the PCB industry, their high tooling costs and time‐consuming procedures are willingly exchanged by digital printing, following the establishment of this technology both in everyday office uses and in a variety of industrial applications. In the PCB industry, a number of companies have recently begun to offer various digital printing system configurations. This paper discusses the basic requirements of PCB ink‐jet printing systems. Possible solutions and basic system engineering considerations are presented, to show the optimal system configuration.
Immersion tin: a proven final finish for printed circuit boards providing reliable solderability and marginal formation of tin‐whiskers
Authors: Meeh Peter
Published: September 2004

This paper describes a state‐of‐the‐art process for immersion tin plating of PCBs which is used to preserve solderability prior to assembly. The process sequence is described and preventive measures for handling the final surface finish is documented. A solderability test method and basic requirements for fluxes and soldering parameters are also described. Quantitative results on the formation of intermetallic tin‐copper phases are shown and their influence on the formation of tin whiskers explained. A problem in production is the precise measurement of the tin thickness, therefore different measuring methods are also detailed. Finally, the mechanism of tin deposition and the formation of tetravalent tin and the relationship with bath age and deposit quality are discussed.
Open linking for libraries: the OpenURL framework
Authors: Walker Jenny
Published: September 2004

Reports on the ground‐breaking work by Herbert Van de Sompel while associated with Ghent University, Belgium, and at the Los Alamos National Laboratory, which has led to the creation of an open linking framework for scholarly research. The open linking framework proposed by Van de Sompel puts libraries firmly in control, allowing them to determine the scope of their institution’s interlinked research environment both in terms of extent and range of link services offered to their users. It places librarians in the “trail‐blazers” profession, predicted by Vannevar Bush in 1945: they enthuse in the task of establishing useful links between resources. The creation of such an open linking environment requires the collaboration of all the stakeholders in the information industry; and underlying the success of this is an emerging standard, the OpenURL, now on a fast track path to acceptance by NISO. Van de Sompel’s research work led to the development of the SFX server technology, which was demonstrated in operation at both the Ghent University and the Los Alamos National Laboratory. Ex Libris subsequently purchased the SFX server technology from Ghent University in early 2000.
Living by the code: some issues surrounding a code of conduct for the LIS profession
Authors: Freeman Mike
Published: September 2004

Examines the requirements for a code of professional conduct. Outlines the content and operation of the Library Association’s current code of professional conduct. Identifies some problems incurred in operating a code of professional conduct, together with some of the benefits of operating within the framework of such a code. Includes some thoughts on the future of a code of professional conduct for librarians.
Negative symbolic consumption and consumers’ drive for self‐esteem
Authors: Banister Emma N. , Hogg Margaret K.
Published: September 2004

Self‐esteem is an important motivational drive for consumption involving both the acceptance and rejection/avoidance of symbolic goods. This paper examines the relationship between self‐esteem and the rejection of goods and brands within the context of fashion consumption by young professionals. A conceptualisation which accounts for consumers’ use of various strategies in their efforts to maintain or enhance their self‐esteem is suggested. A small‐scale exploratory study is used to examine first, how consumers invest products and brands with negative symbolic meanings; and second, how this leads consumers to reject products and brands. The importance of understanding negative symbolic consumption when marketing high involvement products such as fashion goods is identified; and the implications for fashion retailers and marketing management are discussed.
Switching barriers in consumer markets: an investigation of the financial services industry
Authors: Colgate Mark , Lang Bodo
Published: September 2004

Much research looks at why customers switch service organizations but there has been less focus on why customers do not switch service organizations, even though they have seriously considered doing so. In light of this, we present an analysis of the literature and develop a list of potential switching barriers. These switching barriers are then empirically tested within two financial services industries. Results from over 400 consumers enable us to ascertain not only the importance of each switching barrier but also to develop a more parsimonious understanding of these barriers, through factor analysis. The results reveal similar patterns in the two industries in respect to switching barriers. The first of the four factors contains reasons related to apathy, the second factor contains negative reasons for customers staying with their current service provider, the third factor relates to relationship variables and the final factor relates to service recovery. Results clearly indicate that the first two factors are far more important than the latter two in terms of why customers stay even when they seriously considered leaving.
Professional integrity in the age of managed care: views of physicians
Authors: Quaye Randolph
Published: September 2004

At the end of 1997, one quarter of the American public used health maintenance organizations. This paper reports findings on physicians’ perspectives on the role of managed care in their professional practices. The research data come from mailed surveys to physicians who are selected from the Cigna Directory of Physicians practicing in the State of Ohio. Subjects were asked to explain what managed care meant to them, and how long they have been practicing medicine. Questions also focused on professional autonomy, quality of care and career aspirations for the future. The results from the study suggest that managed care has had a negative impact on how physicians practice medicine. Several of our respondents reported that they are playing the role of a “double agent” and feel a sense of frustration in doing so. The degree of antipathy toward managed care differs between primary care physicians and specialists.
Advice for an action researcher
Authors: Mumford Enid
Published: September 2004

Discusses the role and problems of the socio‐technical action researcher at different stages of a project. It is based on the author’s personal experience when using action research as a method for assisting the successful democratic design and implementation of information systems.
The play of information systems development
Authors: Westrup Christopher
Published: September 2004

Seeks to show the ritual and dramatic elements in an ostensibly rational and technocratic process; that is, the formulation of nurses’ information requirements prior to the introduction of a computerized nursing information system in a large hospital. Suggests that ritual is an important social process in times of change within organizations and that there are close affinities between ritual and theatrical performance. What is interesting is that a process of intensifying the measurement of performance and the monitoring of work, apparently attributes of rational managerial practice, appear to be enacted in conditions which are redolent of ritual and of theatre. It is this somewhat paradoxical juxtaposition of the introduction of new technologies, replete with scientific allusions and the decidedly non‐rational social practices that accompany them, which lead to a questioning of the efficacy of notions of efficient and rational management and the role of new technologies in supporting these ideals.
The curious case of the disentangled debit
Authors: Bittlestone Robert
Published: September 2004

Takes a humorous view, using Sherlock Holmes and Dr Watson, in setting up a hypothetical case of derivative investigation by the two sleuths. Asks a few questions along the way and uses a figure to add emphasis to “the entangled equilibrium of principal and interest”. Cryptic clues abound in this with a good message for practitioners.
Retrospective conversion of library catalogs in UK institutions of higher education: a quantitative analysis
Authors: Sweeney Russell
Published: September 2004

As part of an investigation as to whether a national retrospective catalog conversion program is justified, presents a summary of the results of a survey of retrospective conversion programs in UK higher education libraries. The survey was conducted by the author in association with Philip Bryant of the University of Bath. Questionnaires were sent to 266 higher education libraries in the UK.