bluuebunny/crossref_metadata_2025 huggingface dataset:
Signal transduction of erbB receptors in trastuzumab (Herceptin) sensitive and resistant cell lines: Local stimulation using magnetic microspheres as assessed by quantitative digital microscopy
Authors: Friedländer Elza , Arndt‐Jovin Donna J. , Nagy Péter , Jovin Thomas M. , Szöllősi János , Vereb György
Published: September 2005

Background

ErbB2 (HER‐2), a member of the epidermal growth factor (EGF) receptor family, is a class I transmembrane receptor tyrosine kinase. Although erbB2 has no known physiologic ligand, it can form complexes with other members of the family and undergo transactivation of its very potent kinase activity, thereby initiating downstream signaling and cell proliferation. ErbB2 is a frequent pathologic marker in ductal invasive breast carcinomas and is targeted by using a specific humanized monoclonal antibody, trastuzumab (Herceptin). The antibody is effective in only 20% to 50% of erbB2‐positive tumors, and this resistance, as yet poorly understood, constitutes a major therapeutic challenge.

Methods

Magnetic microspheres coated with ligands or antibodies are widely used for separation of proteins and cells and allow localized, high intensity, and precisely timed stimulation of cells. We used EGF‐ and trastuzumab‐covered paramagnetic microspheres, quantitative confocal laser scanning microscopy, and digital image processing to investigate the (trans)activation of and local signal propagation from erbB1 and erbB2 on trastuzumab sensitive and resistant carcinoma cell lines expressing these receptors at high levels.

Results

On A431 cells expressing high levels of endogenous erbB1 and transfected erbB2‐mYFP (A4‐erbB2‐mYFP F4 cell line), EGF‐coupled‐microspheres activated erbB1 and transactivated erbB2‐mYFP. In two other cell lines with comparable erbB2 expression but lower levels of erbB1, EGF microspheres transactivated erbB2 less efficiently. Trastuzumab in solution activated erbB2 on A4‐erbB2‐mYFP and the trastuzumab sensitive SKBR‐3 cells, but only negligibly on the resistant JIMT‐1 cells that showed a 10 times higher Kd for the antibody. Nevertheless, pronounced erbB2 activation and tyrosine phosphorylation could be detected after stimulation with trastuzumab‐coupled microspheres in all cell lines, although transactivation of erbB1 was negligible. Receptor phosphorylation was restricted to the immediate proximity of the microspheres, i.e., receptor clusters external to these locations remained inactive.

Conclusion

ErbB1 ligand and erbB2 specific antibody attached to magnetic microspheres are efficient tools in assessing erbB activation, localized signal propagation, and erbB heterodimer formation. Trastuzumab coupled to microspheres is more efficient at accessing erbB2 and activating it than trastuzumab in solution. © 2005 International Society for Analytical Cytology
Computer program for analyzing donor photobleaching FRET image series
Authors: Szentesi Gergely , Vereb György , Horváth Gábor , Bodnár Andrea , Fábián Ákos , Matkó János , Gáspár Rezső , Damjanovich Sándor , Mátyus László , Jenei Attila
Published: September 2005

Background

The photobleaching fluorescence resonance energy transfer (pbFRET) technique is a spectroscopic method to measure proximity relations between fluorescently labeled macromolecules using digital imaging microscopy. To calculate the energy transfer values one has to determine the bleaching time constants in pixel‐by‐pixel fashion from the image series recorded on the donor‐only and donor and acceptor double‐labeled samples. Because of the large number of pixels and the time‐consuming calculations, this procedure should be assisted by powerful image data processing software. There is no commercially available software that is able to fulfill these requirements.

Methods

New evaluation software was developed to analyze pbFRET data for Windows platform in National Instrument LabVIEW 6.1. This development environment contains a mathematical virtual instrument package, in which the Levenberg‐Marquardt routine is also included. As a reference experiment, FRET efficiency between the two chains (β2‐microglobulin and heavy chain) of major histocompatibility complex (MHC) class I glycoproteins and FRET between MHC I and MHC II molecules were determined in the plasma membrane of JY, human B lymphoma cells.

Results

The bleaching time constants calculated on pixel‐by‐pixel basis can be displayed as a color‐coded map or as a histogram from raw image format.

Conclusion

In this report we introduce a new version of pbFRET analysis and data processing software that is able to generate a full analysis pattern of donor photobleaching image series under various conditions. © 2005 International Society for Analytical Cytology
Biological microbeads for flow‐cytometric immunoassays, enzyme titrations, and quantitative PCR
Authors: Pataki Judit , Szabó Miklós , Lantos Erika , Székvölgyi Lóránt , Molnár Mónika , Hegedüs Éva , Bacsó Zsolt , Kappelmayer János , Lustyik György , Szabó Gábor
Published: September 2005

Background

Introduction of microbeads into flow‐cytometry has created a new scenario, making quantitative measurement of molecules dispersed in a homogeneous phase, with an extremely wide realm of already realized and potential applications possible. Development of this field has lead to specialized instrumentation and microbead arrays, dedicated to certain applications.

Methods

Formaldehyde‐fixed yeast and bacterial cells were conjugated with avidin and applied as microbeads, to establish a simple, convenient, flexible, and inexpensive flow‐cytometric platform for various immunological and biochemical assays.

Results

We have tested these “biological microbeads” for the simultaneous titration of human α‐fetoprotein (AFP) and human Chorionic Gonadotropin (βhCG) hormone levels, for the titration of proteolytic and nucleolytic (restriction) enzymes, and for quantitative PCR, using biotinylated and fluorescent primers.

Conclusions

The use of biological microbeads for various immunological and biochemical assays has been demonstrated. The flow‐cytometric methods proved to be at least as sensitive as the standard biochemical or immunological tests. For proteinase K activity measurements, a single enzyme molecule in the sample could be detected. The sensitivity, versatility, and low cost of the assays may advance flow‐cytometry to become a central methodological platform in most laboratories. The biological microbeads offer virtually unlimited possibilities for fluorescent labeling (addressing), conjugation of ligand binding molecules, and they are easy to handle and perform well in a multiplex format. © 2005 International Society for Analytical Cytology
Suppression of eosinophilic airway inflammation by treatment with α‐galactosylceramide
Authors: Morishima Yuko , Ishii Yukio , Kimura Toru , Shibuya Akira , Shibuya Kazuko , Hegab Ahmed E. , Iizuka Takashi , Kiwamoto Takumi , Matsuno Yosuke , Sakamoto Tohru , Nomura Akihiro , Taniguchi Masaru , Sekizawa Kiyohisa
Published: September 2005

To clarify the essential role of NKT cells in allergy, we investigated the contribution of NKT cells to the pathogenesis of eosinophilic airway inflammation using α‐galactosylceramide (α‐GalCer), a selective ligand for NKT cells. Although continuous administration of α‐GalCer during ovalbumin (OVA) sensitization increased OVA‐specific IgE levels and worsened eosinophil inflammation, a single administration of α‐GalCer at the time of OVA challenge completely prevented eosinophilic infiltration in wild‐type mice. This inhibitory effect of α‐GalCer was associated with a decrease in airway hyperresponsiveness, an increase in IFN‐γ, and decreases in IL‐4, IL‐5 and IL‐13 levels in the bronchoalveolar lavage fluids. Analysis of lung lymphocytes revealed that production of IFN‐γ increased in NK cells, but not in T or NKT cells, following α‐GalCer administration. Induction of vascular cell adhesion molecule‐1 in the lungs of wild‐type mice was also significantly attenuated by treatment with α‐GalCer. These effects of α‐GalCer were abrogated in Jα281–/– mice, which lack NKT cells, and in wild‐type mice treated with anti‐IFN‐γ Ab. Hence, our data indicate that α‐GalCer suppresses allergen‐induced eosinophilic airway inflammation, possibly by inducing a Th1 bias that results in inhibition of eosinophil adhesion to the lung vessels.

See accompanying commentary: http://dx.doi.org/10.1002/eji.200535425
Help signals provided by lymphokines modulate the activation and apoptotic programs induced by partially agonistic peptides in specific cytotoxic T lymphocytes
Authors: Uhlin Michael , Sandalova Elena , Masucci Maria Gracia , Levitsky Victor
Published: September 2005

Inefficient recognition of altered peptide ligands (APL) by specific CTL is believed to contribute to the failure of immune control over tumors and progressive viral infections. A link between deficient help signals and the appearance of CTL epitope mutants has been suggested by recent studies. However, the regulation of APL activity by immunologic help is not well understood. We analyzed the capacity of exogenous IL‐2 and IL‐15, which are physiologically produced by cells of the adaptive and innate immune system, respectively, to modulate proliferation, responsiveness to repeated stimulation and apoptotic programs triggered in specific CTL by either fully or partially agonistic peptide ligands. We show that signals induced by the lymphokines synergize with weak TCR signaling induced by partially agonistic APL, converting many of these peptides from inhibitory to stimulatory ligands. Some APL partially suppress the responsiveness of specific CTL to secondary stimulation, while this inhibitory effect is diminished if APL‐stimulated cells are cultured in the presence of either of the lymphokines. We also demonstrate that IL‐2 and IL‐15 suppress up‐regulation of the Bcl‐2 family member Bim and induction of a death receptor‐independent apoptotic program triggered by partially agonistic APL. Our results suggest that under conditions of insufficient immunologic help, partially agonistic APL may actively suppress specific CTL responses and become especially advantageous for immune escape of tumors or viruses.
In situ measurements of sediment settling characteristics in ﬂoodplains using a LISST‐ST
Authors: Thonon Ivo , Roberti Johannes R. , Middelkoop Hans , van der Perk Marcel , Burrough Peter A.
Published: September 2005

Due to a lack of data on settling velocities (ws) and grain size distributions (GSDs) in ﬂoodplain environments, sedimentation models often use calibrated rather than measured parameters. Since the characteristics of suspended matter differ from those of deposited sediment, it is impossible to derive the ws and GSD from the latter. Therefore, one needs to measure in situ suspended sediment concentrations (SSCs), settling velocities, effective grain sizes and sedimentation ﬂuxes. For this purpose we used the LISST‐ST, a laser particle sizer combined with a settling tube.

In 2002 (twice) and 2004, we located the LISST‐ST with an optical backscatter sensor and sediment traps in two ﬂoodplains in The Netherlands: one along the unembanked IJssel River, another along the embanked Waal River. Measurements revealed that the SSC in the ﬂoodplains varied in relation to the SSC in the river channel. Smaller ﬂocs dominated the SSC, while larger ﬂocs dominated the potential sedimentation ﬂuxes. The in situ GSD in the IJssel ﬂoodplain was signiﬁcantly coarser than in the Waal ﬂoodplain, while the dispersed median grain sizes were equal for both ﬂoodplains. Therefore, the dispersed median grain size was two to ﬁve times smaller than the effective one.

The in situ grain size exhibited a signiﬁcant positive relationship with ws, although the ws for the largest ﬂocs showed high variability. Consequently, the variability in sedimentation ﬂuxes was also large. In the actual sedimentation ﬂuxes, and hence in sedimentation models, in situ grain sizes up to about 20 µm can be neglected. In ﬂoodplain sedimentation models the relation between settling velocity and in situ grain size can be used instead of Stokes's law, which is only valid for dispersed grain sizes. These models should also use adequate data on ﬂow conditions as input, since these strongly inﬂuence the suspended sediment characteristics. Copyright © 2005 John Wiley & Sons, Ltd.
Location, location, location: The role of cyclin D1 nuclear localization in cancer
Authors: Gladden Andrew B. , Diehl J. Alan
Published: September 2005

The control of cell proliferation is crucial in maintaining cellular homeostasis and loss of this mechanism is a principle hallmark of cancer cells. A primary target of growth factor signaling is the cyclin D1‐dependent kinase (D1‐CDK4/6) whose activity promotes G1 phase progression by phosphorylating the retinoblastoma protein (Rb) along with related pocket proteins 107 and p130, relieving inhibition of E2F family transcription factors. Cyclin D1 accumulation is regulated at multiple levels including transcription, post‐translational activation and cellular localization throughout the cell cycle. While overexpression of cyclin D1 has been observed in a number of human cancers, mouse cancer models overexpressing D1 have fallen short of establishing a role for cyclin D1 in the initiation of malignant phenotypes suggesting an additional regulatory mechanism exists that prevents cyclin D1‐driven cancer. This article will present an overview of current data investigating the regulation of cyclin D1 nuclear localization and the prevalence of these aberrations in cancer. Finally, future avenues of research involving cyclin D1 cellular localization and its regulation in cancer will be addressed. J. Cell. Biochem. © 2005 Wiley‐Liss, Inc.
Phylogenetic patterns of enamel microstructure in dinosaur teeth
Authors: Hwang Sunny H.
Published: September 2005

The tooth enamel microstructure of all the dinosaur taxa that are adequately represented in the American Museum of Natural History collections were analyzed using scanning electron microscopy. This study aims to determine whether or not better sampling within a major nonmammalian amniote (hereafter referred to descriptively as “reptile”) clade will unearth phylogenetic patterns in enamel microstructure in addition to those dictated by tooth function. While interest in reptile enamel microstructure has increased in the past few years, intensive sampling focused on just one monophyletic reptile clade was not previously implemented. This study reveals that phylogenetic constraints play a larger role in shaping enamel microstructure in reptiles than previously thought. Within many monophyletic dinosaur clades the combination of enamel types and enamel features within a tooth—the schmelzmuster—is the same in all the taxa due to their common ancestry, and their schmelzmusters are diagnostic of their respective clades. While distantly related taxa with similar teeth and diets have similar schmelzmusters due to functional constraints, phylogenetic constraints keep those schmelzmusters distinct from one another. An interesting finding of this analysis is that the enamel complexity of a taxon does not necessarily coincide with the position of the taxon on a phylogenetic tree; more derived taxa do not necessarily have more derived enamel and more primitive taxa do not necessarily have more primitive enamel. J. Morphol. © 2005 Wiley‐Liss, Inc.
The enterprise system lifecycle: through a knowledge management lens
Authors: Gable Guy G.
Published: September 2005

This paper argues the importance of a lifecycle‐wide knowledge sourcing strategy in support of the Enterprise System (ES) investment.

It emphasizes the need for research into more effective and cooperative ES knowledge management across the three key players — the ES vendor, the ES implementation partner or consultant, and the ES‐using client organization.

Copyright © 2005 John Wiley & Sons, Ltd.
Are ERP systems a source of competitive advantage?
Authors: Seddon Peter B.
Published: September 2005

Packaged enterprise application software vendors claim that ERP systems are a source of competitive advantage. On the other hand, Nicholas Carr says that IT has become a commodity, and therefore that investments in IT, including ERP, are unlikely to be sources of competitive advantage. This paper asks who is right.

Evidence from three surveys and a single case study suggests that ERP systems provide benefits such as improved information visibility, personnel and inventory reduction, productivity improvement and new improved processes. However, since ERP software has been available for many years, and benefits such as those listed have been realized by many firms, it is argued that ERP software is an unlikely source of competitive advantage either through opportunities for strategic positioning or through gains in operational effectiveness.

Copyright © 2005 John Wiley & Sons, Ltd.
Application of direct thermal desorption gas chromatography and comprehensive two‐dimensional gas chromatography coupled to time of flight mass spectrometry for analysis of organic compounds in ambient aerosol particles
Authors: Schnelle‐Kreis Jürgen , Welthagen Werner , Sklorz Martin , Zimmermann Ralf
Published: September 2005

Semivolatile organic compounds (SVOC) associated with ambient particles smaller than 2.5 μm (PM2.5) were determined in the city of Augsburg, Germany. Daily samples were collected at a central monitoring station from late summer 2002 to spring 2005. SVOC were analysed by direct thermal desorption (DTD)‐GC and comprehensive 2‐D GC coupled to TOF MS (DTD‐GC‐TOF MS and DTD‐GC×GC‐TOF MS). Two hundred compounds were quantified and ‘semi‐quantified’ on a daily basis by DTD‐GC‐TOF MS. n‐Alkanes, n‐alkan‐2‐ones, n‐alkanoic acid methyl esters, acetic acid esters, n‐alkanoic acid amides, nitriles, linear alkylbenzenes and 2‐alkyl‐toluenes, hopanes, PAH, alkylated PAH and oxidised PAH, and several compounds that are not grouped in homologous rows or compound classes were determined. Changes in concentration and pattern of several target compounds as well as methodological advantages and restrictions of DTD‐GC‐TOF MS are briefly discussed. DTD‐GC‐TOF MS analysis provided data particularly suited for source receptor modelling and epidemiological time series studies on the health effects of ambient PM. GC×GC enhances chromatographic resolution of PM samples and therefore amplifies the peak identification capabilities of the TOF MS.
Some advantages of high temperature for the separation of pharmaceutical compounds with mass spectrometry detection
Authors: Albert Monique , Cretier Gérard , Guillarme Davy , Heinisch Sabine , Rocca Jean‐Louis
Published: September 2005

The beneficial effects of high temperature on separation and detection of basic compounds, the detection being performed by MS via ESI, are investigated. The influence of various parameters on both separation and detection performances is studied. These parameters include the mobile phase pH, the temperature, and the type of stationary phase. Experiments are performed under gradient elution conditions. The results obtained with four different supports, silica‐, zirconia‐, carbon‐, and polymer‐based columns, are compared by means of different criteria including the elution composition, the peak asymmetry, and the S/N. High temperature liquid chromatography at high pH with volatile buffers suitable for MS detection was shown to be an interesting choice for solutes with basic sites.
Supramolecular systems‐based extraction‐separation techniques coupled to mass spectrometry
Authors: Merino Francisco , Rubio Soledad , Pérez‐Bendito Dolores
Published: September 2005

The combination of supramolecular chemistry and MS has not only been fruitful in the field of gas‐phase fundamental studies of host–guest complexes and supramolecular assemblies. Mass spectrometric analysis has also benefited from the ability of supramolecular systems to behave as pseudophases in which solutes partition from the bulk solvent phase. Supramolecular systems‐based extraction and concentration schemes and separation techniques have been widely used in different fields of analytical chemistry and are ideally suited for coupling with MS. This review describes the present status of the application of supramolecular chemistry in mass spectrometric analysis and includes topics such as the use of coacervative liquid–liquid extraction and hemimicelle/admicelle‐based SPE of organic compounds prior to chromatography and electrophoresis. It also discusses the recent advances in enantioselective analysis using CD in electrophoresis‐ and chromatography‐MS. The potential and analytical challenges of these approaches in environmental and bioanalytical chemistry, where one can expect significant developments in the future, are outlined.
Hydride‐based silica stationary phases for HPLC: Fundamental properties and applications
Authors: Pesek Joseph J. , Matyska Maria T.
Published: September 2005

Silica hydride is a recent development in chromatographic support materials for HPLC where hydride groups replace 95% of the silanols on the surface. This conversion changes many of the fundamental properties of the material as well as the bonded stationary phases that are the result of further chemical modification of the hydride surface. The general approach for fabricating the silica hydride and subsequent bonded phases is reviewed. Properties of the silica hydride surface are compared to those of the standard material obtained in the preparation of most commercial HPLC stationary phases. Some unique chromatographic properties of hydride‐based phases are described as well as some general application areas where these bonded materials may be used in preference to or have advantages not available from typical stationary phases.
Electric field gradient focusing
Authors: Kelly Ryan T. , Woolley Adam T.
Published: September 2005

Electric field gradient focusing (EFGF) is a relatively new separation technique with promising attributes, particularly for protein analysis. The fundamental fractionation mechanism in EFGF involves a gradient in electric field along the length of a separation column. The electrophoretic force that drives charged analytes in a region of changing electric field is opposed by a constant, pressure‐driven bulk fluid flow. When the electrophoretic velocity of a particular moiety is equal and opposite to the velocity of the fluid flow, the analyte focuses into a stationary band. Thus, EFGF can both concentrate and separate charged species according to electrophoretic mobility. To date, the electric field gradients needed for EFGF have been established using a number of different approaches, including channels having changing cross‐sectional areas, conductivity gradients caused by the diffusion of buffer ions across a membrane, electrode arrays, and temperature gradients in buffers whose conductivities change as a function of temperature. EFGF has proven particularly effective for sample enrichment, with concentration factors of 10 000 reported. In this article we review advances in EFGF technology and discuss prospects for further improving EFGF for chemical analysis.
The effect of ionic peneration on semiconducting behaviour of temporarily protective oil coating on the surface of AISI 304 stainless steel
Authors: Zhong Q. , Rohwerder M. , Shi L.
Published: September 2005

In this paper, the semiconducting behaviour of temporarily protective oil coatings on the surface of naked and prepassivated AISI 304 stainless steel immersed in 3% aqueous NaCl solution was studied by utilizing potential‐capacitance methode, Mott‐Schottky analysis and impedance analysis. It was pointed out that the temporarily protective oil coating behaves as a semiconductor during its degradation. The ionic penetration and the substrate greatly affect the conduction behaviour of the oil coating. On the surface of naked AISI 304 stainless steel, the oil coating behaves as a n‐type semiconductor. With increasing immersion time, the donor density of the space charge layer in the temporarily protective oil coating increases from 1019 to 1025 m−3. However, on the surface of the prepassivated substrate the space charge layer in the oil coating is significantly affected by the oxide on the steel electrode. In this case immersion time does not influence the density of charge carriers in the oil coating (1021 m−3). Impedance analysis also verify above results.
Electrorheology of Multiwalled Carbon Nanotube/Poly(methyl methacrylate) Nanocomposites
Authors: Park Seung J. , Cho Min S. , Lim Sung T. , Choi Hyoung J. , Jhon Myung S.
Published: September 2005

Summary: Multiwalled carbon nanotube (MWNT) nanocomposites dispersed in a poly(methyl methacrylate) (PMMA) matrix were prepared via suspension polymerization, in which radicals induced on the outer wall of the MWNTs by 2,2′‐azoisobutyronitrile initiate the grafting of PMMA. The synthesized MWNT/PMMA nanocomposite particles were found to have a spherical shape and exhibit a high electrical conductivity, mainly as a result of the carbon nanotubes. A suspension was prepared with MWNT/PMMA particles in insulating silicone oil and its electrorheological properties were investigated by controlling applied direct current (DC) electric field strengths.

Flow curve possessing a region analogous to the coexistence curve.

magnified image

Flow curve possessing a region analogous to the coexistence curve.
Giant Complex Modulus Reduction of κ‐Carrageenan Magnetic Gels
Authors: Mitsumata Tetsu , Nagata Akiyasu , Sakai Kazuki , Takimoto Jun‐ichi
Published: September 2005

Summary: Effects of magnetization on the complex modulus of κ‐carrageenan magnetic gels have been investigated. The magnetic gel was made of a natural polymer, κ‐carrageenan, and a ferromagnetic particle, barium ferrite. The complex modulus of the magnetic gel was investigated by dynamic viscoelastic measurements with a compressional strain. It was first observed that the magnetic gels showed giant storage modulus reduction ≈107 Pa before and after magnetization. The reduction was nearly independent of the frequency, and it increased with increasing the volume fraction of the ferrite. The maximum reduction in the storage modulus reached 14.9 MPa which corresponds to 76.5% of the modulus before magnetization. It was also found that the change in the modulus was nearly independent of a magnetization direction. Magnetism and morphology of the magnetic gels were also presented.

Strain dependence of the storage modulus at 1 Hz for κ‐carrageenan gel (□) and its magnetic gel before (○) and after (•) magnetization (ϕ = 0.39). The geometry of magnetization and strain directions is perpendicular.

magnified image

Strain dependence of the storage modulus at 1 Hz for κ‐carrageenan gel (□) and its magnetic gel before (○) and after (•) magnetization (ϕ = 0.39). The geometry of magnetization and strain directions is perpendicular.
Chain‐Length Dependence of the Electrochemical Properties of Conjugated Oligofluorenes
Authors: Chi Chunyan , Wegner Gerhard
Published: September 2005

Summary: Electrochemical properties of monodisperse oligofluorenes (OFn, n = 2 to 7) and corresponding polyfluorene were studied by cyclic and differential pulse voltammetry. In combination with data of UV‐vis absorption spectra, a series of linear relations such as the band gap, the oxidation potential, the ionization potential, and the electron affinity with the reciprocal number of the fluorene units (1/n) were deduced. When a chain length of ca. 14 repeat units is reached, a stable structure of about one positive charge per 3.5 repeat units is obtained.

magnified image
Photo‐Induced Solid‐State Crosslinking of Electrospun Poly(vinyl alcohol) Fibers
Authors: Zeng Jun , Hou Haoqing , Wendorff Joachim H. , Greiner Andreas
Published: September 2005

Summary: Poly(vinyl alcohol) (PVA) was derivatized by polymer analogous reaction with thienyl acryloyl chloride and processed to submicrometer fibers by electrospinning from aqueous solution. Water solubility of otherwise water‐soluble PVA fibers was reduced considerably by UV crosslinking of thienyl acrylate modified PVA fibers in the solid state. Water stability of these crosslinked fibers was proven by water steam test at 95 °C.

UV/Vis spectrum of PVA‐Thio fibers irradiated for different periods at 300 nm.

magnified image

UV/Vis spectrum of PVA‐Thio fibers irradiated for different periods at 300 nm.
Analysis of count data using poisson regression
Authors: Hutchinson M. Katherine , Holtman Matthew C.
Published: September 2005

Nurses and other health researchers are often concerned with infrequently occurring, repeatable, health‐related events such as number of hospitalizations, pregnancies, or visits to a health care provider. Reports on the occurrence of such discrete events take the form of non‐negative integer or count data. Because the counts of infrequently occurring events tend to be non‐normally distributed and highly positively skewed, the use of ordinary least squares (OLS) regression with non‐transformed data has several shortcomings. Techniques such as Poisson regression and negative binomial regression may provide more appropriate alternatives for analyzing these data. The purpose of this article is to compare and contrast the use of these three methods for the analysis of infrequently occurring count data. The strengths, limitations, and special considerations of each approach are discussed. Data from the National Longitudinal Survey of Adolescent Health (AddHealth) are used for illustrative purposes. © 2005 Wiley Periodicals, Inc. Res Nurs Health 28: 408–418, 2005.
Randomized study of stability and change in patients' advance directives
Authors: Froman Robin D. , Owen Steven V.
Published: September 2005

Little is known about ethnic differences in understanding or using advance directives (ADs). Although health practitioners may presume AD intentions are durable over time, there is no supporting evidence. This randomized study intended to (a) examine differences between hospitalized Hispanic and non‐Hispanic patients' AD preferences, (b) assess AD stability, and (c) discover if the Life Support Preferences Questionnaire (LSPQ) influences AD preferences. Hispanics and non‐Hispanics showed no difference in AD preferences. However, non‐Hispanics were more likely to change AD preferences. The LSPQ itself prompted change in AD preferences, delivering an educational effect with no specific educational intent. Change seen in patients' ADs, even over a brief interval, suggests revisiting AD preferences with patients and their families after hospitalization. © 2005 Wiley Periodicals, Inc. Res Nurs Health 28: 398–407, 2005.
Higher‐order factor analysis of an instrument with dichotomous data
Authors: Baldwin Kathleen A. , Grinslade Margaret S. , Baer Lynn C. , Watts Parris , Dinger Mary K. , McCubbin Jan
Published: September 2005

This article reports the use of higher‐order factor analysis to examine the underlying dimensions of an instrument designed to measure community acceptance of nurse practitioners/physician's assistants. The instrument consisted of both dichotomous and Likert scale items. Use of factor analysis with dichotomous data is controversial. Higher‐order factor analysis provides a potential solution to this dilemma. Following initial factor analysis using maximum likelihood extraction with oblique rotation, the factor correlation matrix was factored to obtain second order factors. The second order factors were interpreted using the factor pattern matrix and examining correlations of individual survey items with the second order factors. This procedure provides additional factorial validity of the underlying uni‐ and multidimensional concepts related to acceptance of NPs and PAs in rural settings: knowledge, competence, access, and trust. © 2005 Wiley Periodicals, Inc. Res Nurs Health 28: 431–440, 2005.
Spin‐adapted states: A basis for quantum dot structure calculation
Authors: Muhandiramge R. D. , Wang J. B.
Published: September 2005

The exact diagonalization method using a spin‐adapted basis is employed to calculate the electronic structure of a multi‐electron quantum dot. By isolating spin and orbital angular momentum eigenstates, we have significantly reduced the size of the matrices required in comparison with the standard configuration interaction method. A novel approach to the simplification of the interaction integrals that arise in the calculation is also presented, which allows exact evaluation of the Hamiltonian matrix required in the calculations. This Mathematica package permits accurate calculation of energy levels and wave functions for both ground and excited states of multiple electrons confined in a circular quantum dot. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
sonographic assessment of the symptomatic breast – a pictorial review
Authors: howlett d. c. , marchbank n. d. p. , allan s. m.
Published: September 2005

ultrasound serves as an essential adjunct to mammography and clinical examination in symptomatic breast evaluation and is the initial imaging modality of choice in some patient groups.

in this review the role of ultrasound in the assessment of the symptomatic breast is discussed and examples of a variety of breast pathologies illustrated.
radiological features of the brittle bone diseases
Authors: paterson c. r.
Published: September 2005

this paper describes some radiological features of osteogenesis imperfecta and temporary brittle bone disease. both conditions cause fractures in early childhood that the parents cannot explain. they can underlie the finding of unsuspected fractures when x-rays are done for other reasons, including fractures of different ages. both can readily be confused with non-accidental injury.

in these disorders any type of fracture can occur; no fracture pattern makes bone disease more or less likely. metaphyseal fractures, often regarded as specific for non-accidental injury, also have a wide range of other causes including several bone diseases. osteopenia cannot be reliably used in diagnosis, not least because it can be absent in some bone diseases such as osteogenesis imperfecta. wormian bones, if present in excess, are a valuable pointer to osteogenesis imperfecta but their absence does not eliminate this diagnosis.

there is growing evidence for the identification of temporary brittle bone disease as a distinctive disorder with its own characteristic clinical and radiological findings.
teleradiology reflections in a district general hospital setting – pleasures, pitfalls and practical pointers
Authors: troughton a. , ramessar j.
Published: September 2005

in 1997 the teleradiology facilities at princess margaret hospital swindon were upgraded to a modern dicom compliant system. we describe the practicalities rather than the technical issues of setting up and running a teleradiology system that can send images to the radiologists' homes on call obviating the need for them in many cases to attend the hospital. we list the initial doubts and concerns voiced by both radiologists and radiographers and describe the means of overcoming the problems that arose. from these reflections we have obtained a deeper insight into the use of teleradiology in a district general hospital (dgh) setting. our conclusions are described.
the lower limb radiographs in accident and emergency departments: red dotting and pattern recognition – a survival guide
Authors: hughes k.
Published: September 2005

the lower limb radiograph is an extremely common request with trauma and the practising radiographer requires familiarity with normal and abnormal appearances. normal variations in anatomy and the variable ossification centres often lead to some confusion. recognition of a haemarthrosis at the knee is clinically very useful and especially with tibial plateau fractures. suggestions for recognition of calcaneal fractures (boehler's angle) and midfoot/forefoot dislocations are illustrated.
towards an integrated model of expertise in medical imaging – part i overview and two dimensions of expert practice
Authors: yielder jill
Published: September 2005

the nature of professional expertise has been widely debated in the literature. however it has been examined primarily from a dichotomy of perspectives – either from an experiential or a cognitive focus, without the attempt to integrate these, and other aspects of expertise into an integrated and coherent model. this article series explicates the nature of professional expertise specifically in the field of medical imaging. it represents a section of the outcomes of a larger study which formulated and illustrated an integrated model of professional expertise also applicable to other professions. it has been written in two parts, part i of which overviews the study and presents two of the five aspects of expertise identified. part ii presents the other three aspects.

the study used data gathered from interviews and critical incident recording from expert medical imaging practitioners in auckland, new zealand, over an extended time frame.

findings showed that while expertise is situated in the context of practice, it incorporates several dimensions working together in an integrated, seamless fashion through the medium of the individual practitioner. the participants identified and illustrated that expertise in medical imaging is a synthesis of a particular knowledge base, the cognitive processes, personality and internal processes of the practitioner. it manifests through, and builds on, interpersonal relationships with patients and other professionals, and is expressed through the actual doing of professional practice. it is through the reflexive examination of practice and management of change that professionals may transform these integrated aspects into the qualitative state of expertise.
investigation of the effects of magnetic fields on memory in occupationally exposed mri radiographers
Authors: gray deirdre a.
Published: September 2005

aims: 1. compare memory ability between ct and mri radiographers using the rey auditory verbal learning test (ravlt) and between mri radiographers working with 1 and 1.5tesla (t) scanners. 2. investigate the change in memory ability (as measured by ravlt) with increasing time worked in mri.

subjects: 11 ct and mri radiographers from four hospital sites were included. each worked exclusively in their modality. ravlt was administered once to each subject. results show no significant difference between mri and ct groups' scores. there were significantly lower scores in subjects who worked more than 5 years in mri and subjects who worked with 1.5t scanners.

the results indicate that static magnetic fields may have a detrimental effect on memory ability. these results indicate the need for further research into the neuropsychological effects of the mri environment on occupationally exposed staff.
Influence of orographically steered winds on Mutsu Bay surface currents
Authors: Yamaguchi Satoshi , Kawamura Hiroshi
Published: September 2005

Effects of spatially dependent sea surface wind field on currents in Mutsu Bay, which is located at the northern end of Japanese Honshu Island, are investigated using winds derived from synthetic aperture radar (SAR) images and a numerical model. A characteristic wind pattern over the bay was evidenced from analysis of 118 SAR images and coincided with in situ observations. Wind is topographically steered with easterly winds entering the bay through the terrestrial gap and stronger wind blowing over the central water toward its mouth. Nearshore winds are weaker due to terrestrial blockages. Using the Princeton Ocean Model, we investigated currents forced by the observed spatially dependent wind field. The predicted current pattern agrees well with available observations. For a uniform wind field of equal magnitude and average direction, the circulation pattern departs from observations demonstrating that vorticity input due to spatially dependent wind stress is essential in generation of the wind‐driven current in Mutsu Bay.
Diagnostics of the large‐scale mixing properties from stratospheric analyses
Authors: Lyjak L. V. , Yudin V. A.
Published: September 2005

We present diagnostics of the large‐scale mixing of stratospheric flows for January 2000 using meteorological analyses produced by the GEOS‐3 system of the Data Assimilation Office (DAO) at NASA Goddard Space Flight Center (GSFC), the European Centre for Medium‐Range Weather Forecasts (ECMWF), and the Met Office (METO). To characterize the mixing properties of these numerical weather prediction (NWP) systems we calculate diffusion coefficients, contour lengthening rates, and equivalent mixing lengths. Qualitatively, our results show relatively good agreement between the mixing parameters in the upper troposphere and lower stratosphere and reveal similar zones of weak and strong mixing in the middle and upper stratosphere. These parameters, however, exhibit substantial quantitative differences in the middle and upper stratosphere. For January 2000, averaged values for the northern hemisphere (NH) show that the GEOS‐3 and ECMWF flows have strong mixing capabilities while the METO winds result in relatively weak mixing and strong transport polar barriers.
Emissions from international shipping: 1. The last 50 years
Authors: Eyring V. , Köhler H. W. , van Aardenne J. , Lauer A.
Published: September 2005

Seagoing ships emit exhaust gases and particles into the marine boundary layer and significantly contribute to the total budget of anthropogenic emissions. We present an emission inventory for international shipping for the past five decades to be used in global modeling studies with detailed tropospheric chemistry. The inventory is a bottom‐up analysis using fuel consumption and fleet numbers for the total civilian and military fleet including auxiliary engines at the end of 2001. Trend estimates for fuel mass, CO2, NOx, and other emissions for the time between 1950 and 2001 have been calculated using ship number statistics and average engine statistics. Our estimate for total fuel consumption and global emissions for the year 2001 is similar to previous activity‐based studies. However, compared to earlier studies, a detailed speciation of nonmethane hydrocarbons (NMHCs) and particulate matter is given, and carbon monoxide emissions are calculated explicitly. Our results suggest a fuel consumption of approximately 280 million metric tons (Mt) for the year 2001 and 64.5 Mt in 1950. This corresponds to 187 (5.4) Tg CO2 (NOx) in 1950, and 813 (21.4) Tg CO2 (NOx) in 2001. From 1970 to 2001 the world‐merchant fleet increased rapidly in terms of ship numbers, with a corresponding increase in total fuel consumption. The fuel consumption estimates are compared against historical marine bunker fuel statistics, and our emission estimates are related to emission budgets of other transport modes. Global ship emissions are distributed geographically according to global vessel traffic densities of the AMVER (Automated Mutual‐assistance Vessel Rescue system) data set for the year 2000. This work also sets the basis to develop future emission scenarios based on average‐fleet emission indices in part 2 of this study.
Impacts of snow and glaciers over Tibetan Plateau on Holocene climate change: Sensitivity experiments with a coupled model of intermediate complexity
Authors: Jin Liya , Ganopolski Andrey , Chen Fahu , Claussen Martin , Wang Huijun
Published: September 2005

An Earth system model of intermediate complexity has been used to investigate the sensitivity of simulated global climate to gradually increased snow and glacier cover over the Tibetan Plateau for the last 9000 years (9 kyr). The simulations show that in the mid‐Holocene at about 6 kyr before present (BP) the imposed ice sheets over the Tibetan Plateau induces summer precipitation decreases strongly in North Africa and South Asia, and increases in Southeast Asia. The response of vegetation cover to the imposed ice sheets over the Tibetan Plateau is not synchronous in South Asia and in North Africa, showing an earlier and, hence, a more rapid decrease in vegetation cover in North Africa from 9 to 6 kyr BP while it has almost no influence on that in south Asia until 5 kyr BP. The simulation results suggest that the snow and glacier environment over the Tibetan Plateau is an important factor for Holocene climate variability in North Africa, South Asia and Southeast Asia.
Observations of equatorial plasma bubbles using broadcast VHF radio waves
Authors: Nakata H. , Nagashima I. , Sakata K. , Otsuka Y. , Akaike Y. , Takano T. , Shimakura S. , Shiokawa K. , Ogawa T.
Published: September 2005

The propagation of VHF radio waves affected by field‐aligned irregularities within equatorial plasma bubbles is examined. Continuous observation of VHF radio waves at Tateyama, Japan, shows that broadcast radio waves transmitted from Southeast Asia propagate to Japan. Using a ray‐tracing calculation combined with a model of scattering by field‐aligned irregularities, we determined scatter points suitable for the reception of these radio waves. The results of the calculation show that radio waves transmitted from the Philippines can propagate to Japan owing to field‐aligned irregularities within equatorial plasma bubbles located west of Japan. Comparing with all‐sky imager data observed at Sata, Japan, we found that the radio waves are received at Tateyama when the plasma bubbles are observed at Sata. The results of this study show that the reception of these radio waves is closely correlated with the equatorial plasma bubbles.
Decrease in Bz prior to the dipolarization in the near‐Earth plasma sheet
Authors: Shiokawa K. , Miyashita Y. , Shinohara I. , Matsuoka A.
Published: September 2005

We examine in detail the rapid decrease in Bz just before dipolarizations observed by the Geotail satellite in the near‐Earth plasma sheet at (XGSM, YGSM) = (−8.3 RE, −5.1 RE). The observations were made using high‐time‐resolution data from a fluxgate magnetometer (16‐Hz sample), a search‐coil magnetometer (128 Hz), and an electric field antenna (64 Hz). Two dipolarizations were observed during a short time interval of 2 min. The magnetic Bz component suddenly decreased 2–4 s prior to the dipolarization. Characteristic waves with frequencies of 5–20 Hz and amplitudes of 1–3 mV m−1 and 5–15 nT s−1 were observed in the electric and magnetic field data at the time of the sudden decreases in Bz. We discuss two possible causes of the sudden decreases in Bz prior to the dipolarizations: (1) passage of a field‐aligned line current associated with the substorm current wedge and (2) explosive growth phase and subsequent disruption of the tail current caused by the observed characteristic field oscillations.