bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changing marine productivity off northern Chile during the past 19 000 years: a multivariable approach
Authors: Mohtadi M. , Romero O. E. , Hebbeln D. 
Published: June 2004

AbstractA multivariable approach utilising bulk sediment, planktonic Foraminifera and siliceous phytoplankton has been used to reconstruct rapid variations in palaeoproductivity in the Peru–Chile Current System off northern Chile for the past 19 000 cal. yr. During the early deglaciation (19 000–16 000 cal. yr BP), our data point to strongest upwelling intensity and highest productivity of the past 19 000 cal. yr. The late deglaciation (16 000–13 000 cal. yr BP) is characterised by a major change in the oceanographic setting, warmer water masses and weaker upwelling at the study site. Lowest productivity and weakest upwelling intensity are observed from the early to the middle Holocene (13 000–4000 cal. yr BP), and the beginning of the late Holocene (<4000 cal. yr BP) is marked by increasing productivity, mainly driven by silicate‐producing organisms. Changes in the productivity and upwelling intensity in our record may have resulted from a large‐scale compression and/or displacement of the South Pacific subtropical gyre during more productive periods, in line with a northward extension of the Antarctic Circumpolar Current and increased advection of Antarctic water masses with the Peru–Chile Current. The corresponding increase in hemispheric thermal gradient and wind stress induced stronger upwelling. During the periods of lower productivity, this scenario probably reversed. Copyright © 2004 John Wiley & Sons, Ltd.
CFOs in e‐business: e‐architects or foot‐soldiers?
Authors: O'Donnell David , Bontis Nick , O'Regan Philip , Kennedy Tom , Cleary Peter , Hannigan Ailish 
Published: June 2004

AbstractBoth the role of the CFO (chief financial officer) and the discipline of accounting can be viewed as being in transition due to developments in the e‐Business world. One perspective suggests that CFOs are becoming ‘e‐process architects’—an alternative suggests that the CFO role is becoming commoditized to ‘foot‐soldier’ status with other roles such as CIOs (chief information officers) and CTOs (chief technology officers) staking a claim to its traditional accounting space. In this paper we present some preliminary evidence relating to this e‐architect/foot‐soldier question, and on levels of e‐Business activity, based on data obtained from over 120 CFOs in the Irish ICT sector. Copyright © 2004 John Wiley & Sons, Ltd.
The influence of knowledge attributes on innovation protection mechanisms
Authors: Nieto Mariano , Pérez‐Cano Carmen 
Published: June 2004

AbstractThis article deals with the appropriability of technological innovations. Specifically, it looks at how certain attributes of technological knowledge (codifiability, teachability, complexity, observability and dependency) may influence the choices that firms make among different protection mechanisms (patents, secrecy, lead time, learning curve and complementary resources). Based on a sample of 670 innovations developed by Spanish industrial firms, it is found that dependency and, to a lesser extent, codifiability are the attributes that have the most influence the choice of appropriation method. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis and Photophysical Investigations of Novel Polymerizable Blue Emitting Fluorophores – Combination of a Hindered Amine with a Benzo[de]isoquinoline‐1,3‐dione
Authors: Bojinov Vladimir , Ivanova Galya , Simeonov Danail 
Published: June 2004

AbstractSummary: New monomeric benzo[de]isoquinoline‐1,3‐dione blue emitting fluorophores, containing hindered amine stabilizer fragment have been synthesized under phase transfer catalysis conditions and their ability for “one‐step” optical bleaching and stabilization of poly(methyl methacrylate) has been demonstrated. During the co‐polymerization, no changes in the chromophoric system of the fluorophore occurred. The chemical bonding of the synthesized monomers in the polymer chain was confirmed spectrophotometrically. The absorption and some basic photophysical characteristics of the low and high molecular weight fluorescent brighteners have been determined. Photostability of the new monomeric fluorophores and their influence on the photostability of the blue emitting side‐group co‐polymers obtained have been established. A significant stabilizing effect against photodegradation was determined.
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Stereochemical Structure of Polypropylene Obtained in the Presence of Half‐Sandwich Titanium Complexes
Authors: Csok Zsolt , Liguori Dario , Sessa Irene , Zannoni Carla , Zambelli Adolfo 
Published: June 2004

AbstractSummary: The polymerization of propene in the presence of CpTi(CH3)3/B(C6F5)3, at low temperature, affords prevailingly syndiotactic elastomeric polypropylene. In the presence of methylalumoxane (MAO) and under the same polymerization conditions, both CpTi(CH3)3 and CpTiCl3 afford elastomeric polypropylene with a stereochemical structure ranging from prevailingly syndiotactic to prevailingly isotactic, depending on the concentration of MAO. A tentative rationalization of these results is provided.The methyl regions of the 13C NMR spectra of polypropylenes obtained for different amounts of MAO (0.001 mol: top and 0.09 mol: bottom).magnified imageThe methyl regions of the 13C NMR spectra of polypropylenes obtained for different amounts of MAO (0.001 mol: top and 0.09 mol: bottom).
Analysis of nucleic acids by FTICR MS
Authors: Hofstadler Steven A. , Sannes‐Lowery Kristin A. , Hannis James C. 
Published: June 2004

AbstractFourier transform ion cyclotron resonance (FTICR) mass spectrometry represents a unique platform with which to study nucleic acids and non‐covalent complexes containing nucleic acids moieties. In particular, systems in which very high mass measurement accuracy is required, very complex mixtures are to be analyzed, or very limited amounts of sample are available may be uniquely suited to interrogation by FTICR mass spectrometry. Although the FTICR platform is now broadly deployed as an integral component of many high‐end proteomics‐based research efforts, momentum is still building for the application of the platform towards nucleic acid‐based analyses. In this work, we review fundamental aspects of nucleic acid analysis by FTICR, focusing primarily on the analysis of DNA oligonucleotides but also describing applications related to the characterization of RNA constructs. The goal of this review article is to give the reader a sense of the breadth and scope of the status quo of FTICR analysis of nucleic acids and to summarize a few recently published reports in which researchers have exploited the performance attributes of FTICR to characterize nucleic acids in support of basic and applied research disciplines including genotyping, drug discovery, and forensic analyses. © 2004 Wiley Periodicals, Inc., Mass Spec Rev 24:265–285, 2005
Biochemical applications of mass spectrometry in pharmaceutical drug discovery
Authors: Geoghegan Kieran F. , Kelly Michele A. 
Published: June 2004

AbstractBiochemical applications of mass spectrometry (MS) are important in the pharmaceutical industry. They comprise compositional analyses of biomolecules, especially proteins, and methods that measure molecular functions such as ligand binding. In early drug discovery, MS is used to characterize essential reagents and in structural biology. A number of MS‐based methods have been proposed for use in high‐throughput screening (HTS), but are unlikely to supplant established radiometric and fluorometric methods for this purpose. These methods, which include pulsed‐ultrafiltration MS, frontal affinity chromatography‐MS, and size‐exclusion chromatography‐MS, may ultimately be most successful in the post‐screening lead development phase. In full development, MS is used heavily in the search for biomarkers that can be used to gauge disease progression and drug action. This review gives equal attention to the technical aspects of MS‐based methods and to selective pressures present in the industrial environment that influence their chances of gaining wide application. © 2004 Wiley Periodicals, Inc., Mass Spec Rev 24:347–366, 2005
Mechanical response and rheological properties of polycarbonate layered‐silicate nanocomposites
Authors: Hsieh Alex J. , Moy Paul , Beyer Frederick L. , Madison Phil , Napadensky Eugene , Ren Jiaxiang , Krishnamoorti Ramanan 
Published: June 2004

AbstractThe effect of clay loading on the mechanical behavior and melt state linear viscoelastic properties of intercalated polycarbonate (PC) nanocomposites was investigated. At low frequencies, the linear dynamic oscillatory moduli data revealed diminished frequency dependence with increasing nanoclay loading. The 3.5 and 5 wt% clay nanocomposites exhibited dramatically altered relaxation behavior, from liquid‐like to pseudo‐solid–like, compared to the pure PC and the 1.5 wt% clay nanocomposite. Thermal degradation of PC resulted from the melt compounding of organo‐modified nanoclays was evident from the reduction in the glass transition temperature and molecular weight of the PC nanocomposites. These nanocomposites also exhibited a significant decrease in the extent of tensile elongation and ductility with respect to the nanoclay incorporation. A concomitant decrease in the rheological properties at high frequencies was also observed, and was consistent with the lowering of the molecular weight of PC, particularly near or above the percolation threshold of nanoclay. These nanocomposites, nevertheless, exhibited elastic‐plastic deformation in compression, regardless of nanoclay content. Polym. Eng. Sci. 44:825–837, 2004. © 2004 Society of Plastics Engineers.
The study of morphology, thermal and thermo‐mechanical properties of compatibilized TPU/SAN blends
Authors: Ulcnik‐Krump M. , De Lucca Freitas L. 
Published: June 2004

AbstractThe compatibilizing efficiency of three different compatibilizers in thermoplastic polyurethane/styrene‐co‐acrylonitrile (TPU/SAN) blends was investigated after their incorporation via melt‐mixing. The compatibilizers studied were poly‐ε‐caprolactone (PCL), a mixture of polystyrene‐block‐polycaprolactone (PS‐b‐PCL) and polystyrene‐block‐poly(methyl methacrylate) (PS‐b‐PMMA), and a mixture of polyisoprene‐block‐polycaprolactone (PI‐b‐PCL) and polybutadiene‐block‐poly(methyl methacrylate) (PB‐b‐PMMA). All compatibilizers were synthesized by living anionic polymerization. Investigations of thermal and thermo‐mechanical properties performed by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DTMA), respectively, were systematically classified into two groups, i.e. blends of TPU or SAN with 20 wt% of different compatibilizers (so‐called limit conditions) and TPU/SAN 25/75 blends with 5 wt% of different compatibilizers. In order to determine the compatibilizer's location, morphology of TPU/SAN 25/75 blends was studied with transmission electron microscopy (TEM). Different compatibilization activity was found for different systems. Blends compatibilized with PCL showed superior properties over the other blends. Polym. Eng. Sci. 44:838–852, 2004. © 2004 Society of Plastics Engineers.
On the use of pressure‐volume‐temperature data of polyethylene liquids for the determination of their solubility and interaction parameters
Authors: Zhao L. , Capt L. , Kamal M. R. , Choi P. 
Published: June 2004

AbstractSpecific volumes of high‐density and low‐density polyethylene liquids at several elevated temperatures and pressures were measured. The measured specific volumes were then used to estimate the thermal expansion coefficients
\documentclass{article}\pagestyle{empty}\begin{document}$\left( {{\rm \alpha = }\frac{{\rm 1}}{v}\left( {\frac{{\partial v}}{{\partial T}}} \right)_P } \right)$\end{document} and isothermal compressibility \documentclass{article}\pagestyle{empty}\begin{document}$\left( {{\rm \beta = } - \frac{{\rm 1}}{v}\left( {\frac{{\partial v}}{{\partial P}}} \right)_T } \right)$\end{document} of the polymers. Two different approaches were used in which one was simply to fit the raw data by second order polynomials to obtain (∂v/∂T)P and (∂v/∂P)T, while the other by the Sanchez‐Lacombe (S‐L) equation of state. It was found that the resultant α and β obtained from the above methods differ significantly, indicating that the S‐L equation of state may not be suitable for determining α and β at elevated temperatures. When these two sets of α and β were used to calculate the corresponding solubility parameters and then the Flory‐Huggins interaction parameters (χ) of the polymers, the results also differ considerably. Nonetheless, χ obtained from the first method agrees well with the results obtained from small angle neutron scattering measurements while the S‐L equation of state method does not. The current results suggest that solubility and interaction parameters obtained from pressure‐volume‐temperature experiments depend critically on the manner by which the data analysis is performed. Polym. Eng. Sci. 44:853–860, 2004. © 2004 Society of Plastics Engineers.
Effect of filler dispersion on polypropylene morphology
Authors: Lozano T. , Lafleur P. G. , Grmela M. , Thibodeau C. 
Published: June 2004

AbstractThe evaluation of filler dispersion in compounding machines is an important part of their design. Calcium carbonate–filled polypropylene (PP) was used as a model compound to study filler dispersion. The evolution of dispersion was followed in a twin‐screw extruder where several types of mixing sections were evaluated. Reverse kneading blocks were found to be very efficient for breakup of agglomerates. Depending on extrusion conditions, agglomeration was observed even after the matrix was melted. To study dispersion in a single‐screw extruder, Maddock and reverse Maddock mixing elements were tried. A quantitative evaluation of the dispersion state allowed a better understanding of nucleation in the PP/CaCO3 matrix. A significant content of the β‐phase of polypropylene was observed when the agglomerate size was relatively small. The level of shear stress was also important for the formation of the β‐phase of PP. The quantification of dispersion was mainly evaluated from micrographs of samples obtained by reflected light microscopy in conjunction with image analysis. The characterization of β‐spherulites was carried out using polarized light microscopy and scanning electron microscopy. Polym. Eng. Sci. 44:880–890, 2004. © 2004 Society of Plastics Engineers.
Fluorescence temperature measurements: Methodology for applications to process monitoring
Authors: Bur Anthony J. , Roth Steven C. 
Published: June 2004

AbstractIn previous publications, we described a technique based on fluorescence spectroscopy to monitor resin temperature during processing. The method consists of using optical fiber sensors to monitor fluorescence from a fluorescent dye that has been doped into the processed resin. Temperature is derived from temperature‐induced changes in the fluorescence spectrum. In practice, a temperature calibration function is obtained from the temperature dependence of the ratio of fluorescence intensities at two wavelengths. In this paper, we address several experimental design issues: (a) the supportive role of fluorescence anisotropy measurements to the measuring concept, (b) the experimental setup used for noncontact measurements during capillary rheometry testing, and (c) molecular‐level environmental issues that arise during reactive processing and temperature profiling. We find that fluorescence anisotropy of the dye bis(2,5‐tert‐butylphenyl)‐3,4,9,10‐perylenedicarboximide (BTBP) is independent of shear rate up to 250 s−1, implying that isotropic orientation of the dye is maintained as the matrix resin undergoes dynamic shear flow, i.e. the calibration function made under quiescent conditions applies to dynamic shear flow conditions. Using this technique in a noncontact application to monitor temperature of the extrudate from a capillary rheometer required an optical design that neutralized the focusing attributes of the cylindrical extrudate. Application to reactive processing is complicated by changes in polarization that accompany the reaction, and, in some cases, produce wavelength shifts in the fluorescence spectrum. We overcome these effects by using a dye that yields a calibration independent of the polarization effects and by averaging over a large dataset to reduce measurement uncertainty. Polym. Eng. Sci. 44:898–908, 2004. © 2004 Society of Plastics Engineers.
Fracture behavior at partially miscible polymer interfaces
Authors: Gorga Russell E. , Narasimhan Balaji 
Published: June 2004

AbstractThe fracture behavior for the partially miscible polystyrene/poly (styrene‐r‐4‐bromostyrene) (PS/PBS) interface is analyzed as a function of miscibility. This is achieved by measuring the fracture energy at PS/PBS interfaces over a range of molecular weights (1370 < N < 7144; N is the degree of polymerization) and annealing conditions (150 < T < 200°C) at varying degrees of miscibility (controlled by ƒ, the volume fraction of brominated repeat units in PBS). Correlations between fracture energy, mutual diffusion coefficient (measured using Rutherford backscattering spectroscopy), and the Flory‐Huggins interaction parameter (χ) are presented. It is shown that the fracture energy, Gc, increases as annealing temperature increases and N and ƒ decrease. The presence of two miscibility‐mediated interdiffusion/fracture regimes is postulated depending upon the value of N*χ, where \documentclass{article}\pagestyle{empty}\begin{document}$N^* = \frac{{2N_{PS} N_{PBS} }}{{N_{PS} + N_{PBS} }}$\end{document}. (I) When N*χ < 2, the system is miscible, Gc is high, and the fracture mechanism is crazing; (II) When N*χ > 2, the system exhibits a miscibility gap, interdiffusion is thermodynamically limited, which results in a decreased Gc, which continues to decrease with increasing ƒ. No crazes are observed in regime II and fracture occurs via chain pullout. Polym. Eng. Sci. 44:929–939, 2004. © 2004 Society of Plastics Engineers.
Primary and secondary gas penetration during gas‐assisted injection molding. Part I: Formulation and modeling
Authors: Li C. T. , Isayev A. I. 
Published: June 2004

AbstractA theoretical study has been carried out on the transient gas‐liquid interface development and gas penetration behavior during the cavity filling and gas packing stage in the gas‐assisted injection molding (GAIM) of a tube cavity. A mathematical formulation describing the evolution of the gas/melt interface and the distribution of the residual wall thickness of skin melt along with the advancement of gas/melt front is presented. The physical model is put forward on the basis of Hele‐Shaw approximation and interface kinematics and dynamics. Numerical simulation is implemented on a fixed mesh covering the entire cavity. The model and simulation can deal with both primary and secondary gas penetrations. The predicted and measuredresults are compared in Part II of this study to validate the theoretical model. Polym. Eng. Sci. 44:983–991, 2004. © 2004 Society of Plastics Engineers.
Primary and secondary gas penetration during gas‐assisted injection molding. Part II: Simulation and experiment
Authors: Li C. T. , Shin J. W. , Isayev A. I. , Lee H. S. 
Published: June 2004

AbstractSimulation and experimental studies have been carried out on the transient gas‐liquid interface development and gas penetration behavior during the cavity filling and gas packing stage in the gas‐assisted injection molding of a spiral tube cavity. The evolution of the gas/melt interface and the distribution of the residual wall thickness of skin melt along with the advancement of gas/melt front were investigated. Numerical simulations were implemented on a fixed mesh covering the entire cavity. The residual thickness of a polymer layer and the length of gas penetration in the moldings were calculated using both the simulation and model developed in Part I of this study and commercial software (C‐Mold). Extensive molding experiments were performed on polystyrene at different processing conditions. The obtained results on the gas bubble dynamics and penetration behaviors were compared with those predicted by the present simulation and C‐Mold, indicating the good predictive capability of the proposed model. Polym. Eng. Sci. 44:992–1002, 2004. © 2004 Society of Plastics Engineers.
The morality of problem selection in proteomics
Authors: Liska Adam J. 
Published: June 2004

AbstractThe emerging power of new technologies in proteomics and the biological sciences to alter the human condition demands that scientists hold a new perspective on the social reesponsibilities of their research. Ethical theory can help scientists recognize not only those research projects that are harmful, but also those research paths that can create the greatest improvements in human health on a global scale. Whereas individual choices are important for the direction of scientific research, these choices may have limited social effects if they are not coordinated with larger institutional and inter‐institutional structures. The perspective presented here calls for the Human Proteome Organization to recognize the ten most ethically significant proteomes to be characterized, with the hopes of rallying support and directing the research efforts of scientists in the proteomics community toward these goals.
Functional protein microarrays for parallel characterisation of p53 mutants
Authors: Boutell Jonathan M. , Hart Darren J. , Godber Benjamin L. J. , Kozlowski Roland Z. , Blackburn Jonathan M. 
Published: June 2004

AbstractUnderstanding the way in which single nucleotide polymorphisms and mutations in the human genome result in individual susceptibility to disease is a major goal in the postgenomic era. Such knowledge should accelerate the development of personalised medicine in which drug treatment can specifically match an individual's genotype. High‐throughput DNA sequencing is generating the initial information required, but new technologies are required that can rapidly characterise the phenotypic effects of the identified polymorphisms. For example, many thousands of allelic variants of the p53 gene have been described and are responsible for more than 50% of cancers, however few of the protein products have been functionally characterised. Here we have quantified in parallel the effects of mutations and polymorphisms on the DNA‐binding function of the p53 oncoprotein using a protein microarray, allowing their subclassification according to functional effect. Protein‐protein interactions between p53 variants and (i) a regulatory oncoprotein, (ii) a regulatory kinase resulting in on‐chip phosphorylation, are also described, suggesting the more general utility of this high‐throughput assay format.
Identification of cellular proteins modified in response to African swine fever virus infection by proteomics
Authors: Alfonso Patricia , Rivera José , Hernáez Bruno , Alonso Covadonga , Escribano José M. 
Published: June 2004

AbstractChanges in gene expression are produced in cells as a consequence of virus infections. In the present work, we used proteomic technology to globally examine African swine fever virus (ASFV)‐infected Vero cells searching for infection‐associated proteins in order to determine target proteins for pathogenesis studies. We studied the alterations in cellular protein profile after ASFV infection by two‐dimensional electrophoresis, identifying the modified cellular proteins by matrix‐assisted laser desorption/ionization peptide mass fingerprinting. A total of twelve different over‐expressed cellular proteins were unambiguously identified. The most significant changes were in redox‐related proteins, nucleoside diphosphate kinases, heat shock proteins, members of the Ran‐Gppnhp‐Ranbd1 complex and apolipoproteins. These cellular protein modifications could represent distinct roles during infection related to apoptosis and transcriptional modulation mechanisms. The present study constitutes the first attempt to understand the dynamics of ASFV‐host cell interactions by proteomics.