bluuebunny/crossref_metadata_2025_split huggingface dataset:
Macroeconomic news and the returns of financial companies
Authors: Ewing Bradley T. 
Published: December 2002

AbstractThis research is concerned with the response of the NASDAQ Financial 100 index to macroeconomic news. The paper employs the newly developed technique of generalized impulse response analysis to examine how macroeconomic shocks affect the performance of the financial sector. The results identify the magnitude and persistence of the response of financial companies stock returns arising from shocks to the stance of monetary policy, real output, inflation, and risk. The findings add to the literature on the determinants of financial sector stocks and on the relationship between the stock market and the macroeconomy. Copyright © 2002 John Wiley & Sons, Ltd.
1H chemical shifts in NMR: Part 19. Carbonyl anisotropies and steric effects in aromatic aldehydes and ketones
Authors: Abraham Raymond J. , Mobli Mehdi , Smith Richard J. 
Published: December 2002

AbstractThe 1H chemical shifts of benzaldehyde, 2‐chloro‐, 2‐hydroxy‐ and 2‐methoxybenzaldehyde, acetophenone, 2‐methoxy‐ and 2‐hydroxyacetophenone, indanone, anthraquinone, fluorenone, anthrone, α‐tetralone, 2,4,6‐trimethylacetophenone, 9‐acetylanthracene, 9‐anthranaldehyde and benzosuberone were obtained and completely assigned in CDCl3 and DMSO solution. In anthrone a keto–enol tautomerism (anthrone–9‐hydroxyanthracene) was observed by NMR in hydrogen bonding solvents but not chloroform. The percentage of enol is linearly dependent on the Kamlett β hydrogen bonding parameter of the solvent, and not the solvent relative permittivity. The chemical shift data allowed the determination of the carbonyl substituent chemical shifts (SCS) in these molecules. These were analysed in terms of the carbonyl electric field, magnetic anisotropy and steric effects for long‐range protons together with a model (CHARGE7) for the calculation of the two‐ and three‐bond effects. The SCS of the carbonyl bond was reproduced with an asymmetric magnetic anisotropy acting at the midpoint of the carbonyl bond with values of Δχpar and Δχperp of 6.36 and −11.88 (10−30 cm3 molecule−1) plus a steric term from the oxygen atom and the CO electric field effect. The short‐range effects of the carbonyl group on the aldehyde proton were modelled using the appropriate β functions in the CHARGE routine. For the 9‐substituted anthracenes the Hückel π calculation was modified to account for the 1H chemical shifts of the H‐10 protons. This model gave a comprehensive calculation of the 1H chemical shifts of these aromatic aldehydes and ketones. For the data set of 129 chemical shifts ranging from δ 2.5 to 11.5 the r.m.s. error of the observed vs calculated shifts was 0.094 ppm. The CO anisotropy and oxygen shielding differ appreciably from the corresponding values for the aliphatic aldehydes and ketones but are similar to the values for the CO group of amides, illustrating the effect of conjugation on these parameters. The model was used in the conformational analysis of some related compounds. In 2‐chlorobenzaldehyde the chemical shift calculations support a non‐planar molecule with the aldehyde–ring dihedral angle in the trans conformer of ca 25°. In the strained seven‐membered ring of benzosuberone, the model was used to test calculated geometries. The ab initio geometry at the B3LYP(6–31++G(d,p)) level gave the best agreement with the observed shifts. Copyright © 2002 John Wiley & Sons, Ltd.
Increasing spectral information with shorter acquisitions: the advantages of using F1 selection in structural determinations
Authors: Yang Shengtian , Gard Janice K. , Harrigan George , Parnas Barry , Likos John , Crouch Ron 
Published: December 2002

AbstractThe structural elucidation of complex materials by NMR is complicated by the common occurrence of nearly coincident resonances. Congested regions necessitate increased spectral resolution, with additional time increments needed for 2D NMR spectroscopy, resulting in longer acquisition times. These demands conflict with the ever‐increasing demands for instrument time and with long‐term sample stability. Selective spectroscopy addresses both of these problems. By focusing attention only on the region of interest, fewer increments are needed. Shorter acquisitions are obtained, with a higher information content. Alternatively, the spectroscopist may choose to use these time savings to collect additional transients, allowing the study of smaller amounts of material, or low‐level impurities/isomers. Using a carbohydrate as our example, we illustrate the utility of this methodology using selHMQC, selHMBC (IMPRESS) and selHMQCTOCSY. We have found this methodology useful in the coupling of efficiency and productivity of NMR spectroscopy. Copyright © 2002 John Wiley & Sons, Ltd.
Lanthanide‐induced shifts in the structural elucidation of β‐hydroxydecalones
Authors: Schenato Rossana A. , dos Santos Éverton M. , Gonçalves Paulo F. B. , Tenius Beatriz S. M. , de Oliveira Eduardo R. , Caracelli Ignez , Zukerman‐Schpector Julio 
Published: December 2002

AbstractThe use of Eu(fod)3 in the analysis of the 1H and 13C NMR spectra of cis and trans‐fused β‐hydroxydecalones is described. The relative configuration of the substituents is discussed using the PMLIS algorithm to determine the lanthanide (Eu) ion position in the complex in an effective axially symmetric model. The conformations of two cis‐decalones are also discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Macropremies: Underprivileged newborns
Authors: Amiel‐Tison Claudine , Allen Marilee C. , Lebrun Francoise , Rogowski Jeannette 
Published: December 2002

AbstractThe focus of neonatal intensive care has been on very low birthweight infants, who comprise only 1.4% of neonates. Too little attention is paid to moderately preterm infants that we call macropremies or moderately low birthweight infants (MLBW, with birthweights 1500–2500 grams). Admitting over half MLBW infants to normal nurseries presumes that they have few needs and an excellent prognosis similar to fullterm newborns. It does not take into account the macropremie's vulnerability to complications of prematurity due to immature organ systems. Obstetricians are increasingly willing to deliver these infants prematurely for signs of fetal distress. As many as 25% of children with cerebral palsy referred to a disability clinic in Paris were MLBW, with hypoxic‐ischemic‐inflammatory associated disorders in one‐third. The majority of MLBW infants who required neonatal intensive care at a tertiary care center in Baltimore had complications of prematurity: 47% had respiratory problems, 20% had feeding intolerance and 9% had hypoglycemia. MLBW infants comprise 5–7% of the neonatal population but account for 14% of neonatal deaths, 18–37% of children with cerebral palsy and 7–12% of children with mental retardation. Increasing the level of neonatal care for the macropremie's transition to extrauterine life would be economically feasible if it prevented as few as 30% of cases of major disability. A change in attitude towards this low risk (but not risk free) group of MLBW infants will both reduce morbidity and improve their health and neurodevelopmental outcome. It includes: 1) Providing an intermediate level of neonatal care for a short duration, with close monitoring and prompt intervention as needed, and 2) Neonatal neurodevelopmental screening to allow focused neurodevelopmental followup of MLBW infants with abnormalities. MRDD Research Reviews 2002;8:281–292. © 2002 Wiley‐Liss, Inc.
Preterm outcomes research: A critical component of neonatal intensive care
Authors: Allen Marilee C. 
Published: December 2002

AbstractWhile early preterm outcome studies described the lives of preterm survivors to justify the efforts required to save them, subsequent studies demonstrated their increased incidence of cerebral palsy, mental retardation, sensory impairments, minor neuromotor dysfunction, language delays, visual‐perceptual disorders, learning disability and behavior problems compared to fullterm controls. Because infants born at the lower limit of viability require the most resources and have the highest incidence of neurodevelopmental disability, there is concern that resources have gone primarily to neonatal intensive care and are not available for meeting the followup, health, educational and emotional needs of these fragile infants and their families. Despite many methodological concerns, preterm outcome studies have provided insight into risk factors for and causes of CNS injury in preterm infants. Nevertheless, it remains difficult to predict neurodevelopmental outcome for individual preterm infants. Perinatal and neonatal risk factors are inadequate proxies for neurodevelopmental disability. Recent randomized controlled trials with one to five year neurodevelopmental followup have provided valuable information about perinatal and neonatal treatments. Recognizing adverse longterm neurodevelopmental effects of pharmacological doses of postnatal steroids is a sobering reminder of the need for longterm neurodevelopmental followup in all neonatal randomized controlled trials. Ongoing longterm preterm neurodevelopmental studies, analysis of changes in outcomes over time and among centers, and evaluation of the longterm safety, efficacy and effectiveness of many perinatal and neonatal management strategies and proposed neuroprotective agents are all necessary for further medical and technological advances in neonatal intensive care. MRDD Research Reviews 2002;8:221–233. © 2002 Wiley‐Liss, Inc.
Ophthalmological problems of the premature infant
Authors: Repka Michael X. 
Published: December 2002

AbstractPreterm infants are more likely than term infants to have significant abnormalities of all parts of the visual system leading to reduced vision. The most common problem is retinopathy of prematurity (ROP). The frequency and severity of this disorder is inversely related to gestational age. Damage ranges from minor to catastrophic. Preterm infants also have higher rates of amblyopia, strabismus, refractive error, and cortical visual impairment. The later problem is largely associated with neonatal brain injury. Years later, these children may develop glaucoma and retinal detachments. MRDD Research Reviews 2002;8:249–257. © 2002 Wiley‐Liss, Inc.
Electrical properties of polymers: space‐charge behaviour in insulating polymers under high‐voltage direct current
Authors: Mizutani Teruyoshi 
Published: December 2002

AbstractThe space‐charge distributions in various low‐density polyethylenes (LDPEs) under a high DC voltage were measured. They strongly depended upon the physical structure of the LDPE, additives, electrode materials, applied field and temperature. Both positive and negative carriers were injected more easily from the semiconductive (SC) electrode than the Al or Au electrode and, as a result, a larger amount of space‐charge was accumulated for the SC electrode. Space‐charge dynamics depended upon the density of LDPE. Injected space‐charge moves more easily toward the counterelectrode in LDPE with a lower density and it decays more quickly after short‐circuiting. Additives, such as antioxidants and by‐products of crosslinking and oxidation of LDPE, strongly affected the space‐charge distribution in LDPE. These results give a good guide for the development of high‐voltage DC (HVDC) extruded polyethylene cables.© 2002 Society of Chemical Industry
Space‐charge measurement in polymer films by the new alternating thermal wave method
Authors: Reboul Jean‐Michel , Carin Régis 
Published: December 2002

AbstractSpace‐charge prospecting is commonly used as a way of evaluating the electrical qualities and reliability of insulating polymers. However, the various methods for space‐charge measurement are not adapted to thin films. The present work is concerned with the development of a new method suitable for thin polymer films intended for the manufacture of capacitors. The principle is the processing of the current response of a film sample submitted to alternating thermal stimulations. A controlled thermo‐electric module is used to generate the thermal stimulations. The current response is processed as arising from an equivalent pattern of discrete charged planes, parallel to the film faces. Some results obtained with this model on 100 µm thick polypropylene films submitted to various treatments are given.© 2002 Society of Chemical Industry
Water absorption in epoxy resins by electronic energy transfer
Authors: Martin O , Pastoriza A , Mikes F , Baselga J 
Published: December 2002

AbstractWater absorption of an epoxy resin was studied by steady‐state fluorescence spectroscopy and gravimetry. It was found that the intrinsic emission of the epoxy resin could be modified selecting an adequate excitation wavelength. The epoxy component of the resin was labelled with a trans‐4‐nitro‐4′‐aminostilbene fluorescent probe. Using an excitation wavelength of 340 nm it was possible to induce energy transfer to the suitable acceptor trans‐4‐nitro‐4′‐dialkylaminostilbene (NDAS). The relative fluorescence intensity I433/I596 was used as a convenient means to follow the quenching effect of water on the emission of NDAS when excited via energy transfer. It was found that both the relative intensity and the water content increase linearly with the square root of diffusion time in the early stages of the process. The apparent Stern–Volmer constants for the quenching of the fluorophore, when excited directly in a fluid THF solution or in the polymer matrix, were very similar but lower than when the fluorophore was excited via energy transfer. It was concluded that, at least in the early stages of the water diffusion process, the interchromophoric distance should increase.© 2002 Society of Chemical Industry
Poly(ethylene oxide) containing segmented networks as precursors for ion‐conducting solid‐state materials
Authors: Cosaert Kathelijne , Eeckhout Els , Goethals Eric , Prez Filip Du , Guégan Philippe , Cheradame Hervé 
Published: December 2002

AbstractSegmented networks containing high contents of poly(ethylene oxide) (PEO) have been investigated as a new type of polymer architecture in the field of solid ion‐conducting materials. Such networks have been synthesized by the radical copolymerization of α,ω‐bis‐methacrylate‐terminated PEO with several types of methacrylates. DMA analysis showed that the phase behaviour of the segmented networks is determined by the fraction and molecular weight of the PEO chains and by the nature of the second component. It has been demonstrated by DSC that, under certain conditions, a small fraction of polymethacrylate is sufficient to prevent the PEO chains from crystallization. Complex impedance measurements of the networks with different concentrations of lithium salt over a wide range of temperatures demonstrated the influence of the nature of the polymethacrylate on the performance of the solid polymer electrolytes. Ionic conductivities at room temperature up to 6 × 10−5 S cm−1 could be achieved for segmented networks containing a minor fraction of poly(n‐butyl methacrylate).© 2002 Society of Chemical Industry
Pendant drop formation on a cylindrical polymeric fibre network: predicting the drop shape and its evolution beyond the traditional Laplace surface tension equation
Authors: Rebouillat Serge , Steffenino Benoit , Salvador Bruno 
Published: December 2002

AbstractWettability of fibres is generally characterised by the contact angle of axisymmetrical drops on single fibres. The use of the inflexion angle was introduced as a more precise parameter useful for characterising fibre–liquid interactions. This method does not cover the case of non‐symmetrical drops that are usually formed on hydrophobic monofilaments. Therefore in order to study all multifilament fibre surfaces, the inflexion angle is combined to the pendant drop description of Bashforth and Adams. The Microwetting® device is used for this purpose and, more specifically, to measure the shape evolution of pendant drops hanging under planar surfaces and fibre networks. Several methods are proposed to calculate the characteristic drop shape factor, Bo, as a function of the inflexion angle. The latter relationship is instrumental in obtaining a complete abacus to classify fibre surfaces. The volume to surface relationship gives rough estimations of Bo, whereas a force balance on a drop volume provide a much more accurate series of data. Experiments were conducted with para‐aramid Kevlar® fibres and with a glass plane; related statistics are presented. Other surfaces and fibre networks serve to validate the approach. A derived wettability ranking is discussed.© 2002 Society of Chemical Industry
Experimental aspects of polymer dynamics
Authors: Richter Dieter , Monkenbusch Michael , Willner Lutz , Wischnewski Andreas , Arbe Arantxa , Colmenero Juan 
Published: December 2002

AbstractNeutron scattering accesses the space time evolution of molecular motion on atomistic length and time scales covering all dynamical processes from local relaxations to overall chain diffusion. Using the dynamics of a chain in the melt as an example, we review results obtained by the various high resolution neutron scattering techniques and outline future opportunities.Copyright © 2002 Society of Chemical Industry
Yield stress of epoxy composites filled with quartz powder
Authors: Rubiolo Gerardo H , Marconi Jorge D , Goyanes Silvia N 
Published: December 2002

AbstractThe effect of the amount of quartz powder in an epoxy resin matrix was studied by compression testing. Compressive tests near room temperature and at several strain rates were performed on samples with different filler volume fractions. The data show that both the composite Young's modulus and yield stress increase with increasing volume fraction of filler. The behaviour of the composite Young's modulus follows the Lewis and Nielsen model with a value for maximum packing fraction of the filler close to that for a random packaging of quartz particles inside the epoxy matrix. In order to understand the behaviour of the yield stress, a model with physical meaning was developed. The observed strengthening effects are explained by an alternative model related to thermal internal stress.© 2002 Society of Chemical Industry
Thermal stability of some self‐assembling hydrogen‐bonded polymers and related model complexes
Authors: Armstrong Gordon , Buggy Martin 
Published: December 2002

AbstractThe thermal stability of polymers is of fundamental importance both in processing and in many applications, eg, injection moulding, hot melts. As part of an investigation to determine the suitability of supramolecular polymers for novel applications in materials science, the thermal behaviour of two model compounds representing the principal classes of supramolecular polymer has been studied in some detail. p‐Methoxybenzoic acid was complexed with 1,2‐di(4‐pyridyl)ethylene in 2:1 ratio as a model compound representing liquid–crystal association chain supramolecular polymers. It is proposed that the model compound degrades as a single species obeying first‐order kinetics; the activation energy (Eact) of the degradation process was calculated to be 127 kJ mol−1. A model ureidopyrimidinone dimer degraded in two steps, also following first order kinetics, with Eact = 71.5 kJ mol−1. The dimer was unaffected by annealing, suggesting that related polymers may be used at elevated temperatures. Polymer analogues of both model compounds were synthesized and their thermal behaviour was found to parallel that of the models. In light of these results, the implications for processing both supramolecular polymers are also considered.© 2002 Society of Chemical Industry
Structural characterization of polymer–liquid crystal dispersions
Authors: Bermudez M D , Carrion‐Vilches F J , Cervantes J J 
Published: December 2002

AbstractLiquid crystalline antiwear fillers were added to thermoplastics such as polystyrene (PS), styrene–acrylonitrile copolymer (SAN) and polyamide 6 (PA). A 1 wt% proportion of thermotropic liquid crystal (LC) 4,4′‐dibutylazobenzene was added to the polymers in powder form and the mixtures were milled. In the case of PS, 10 wt% LC mixtures were also prepared. PS/LC and SAN/LC blends were compression moulded and PA/LC blends were injection moulded from the melt to obtain the modified materials. Cross sections and fracture surfaces were obtained and studied by optical and electron microscopy. Liquid crystal distribution within the polymer matrix depends on the base polymer, the additive proportion and the processing route.© 2002 Society of Chemical Industry
Surlyn®/titanate hybrid materials via polymer in situ sol–gel chemistry
Authors: Siuzdak David A. , Start Paul R. , Mauritz Kenneth A. 
Published: December 2002

AbstractAcid form Surlyn®/titanate hybrid materials were achieved by polymer in
situ sol–gel reactions for a titanium alkoxide monomer. Atomic force microscopic images revealed arrays of titania nanoparticles having diameters of 10–30 nm. Fourier transform infrared spectra verified the presence of an internally polymerized titanate phase although unhydrolyzed TiOR groups were present. Carboxylic acid dimerization was complete at room temperature, but carboxylate anions appeared at higher titanate levels. The methylene rocking doublet persisted upon incorporation of the inorganic component, which supported the idea of largely undisrupted crystallinity. Thermogravimetric analysis showed that the degradation onset temperature of each hybrid is largely unaffected by the presence of the inorganic filler, which is consistent with the concept of an isolated titanate phase. The first‐scan differential scanning calorimetric thermogram for unfilled Surlyn® revealed the usual twin‐melting endotherms. In contrast, the primary, high‐temperature melting endotherm was seen on the first scan for the Surlyn®/titanate hybrids, but the lower temperature endotherm was either not present or weak. Primary melting persisted after several cycles of heating above the melting temperature followed by cooling, demonstrating that primary crystallinity persisted despite titanate phase incorporation. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 11–22, 2003
Morphology and bridging properties of (AB)nmultiblock copolymers
Authors: Rasmussen K. Ø. , Kober E. M. , Lookman T. , Saxena A. 
Published: December 2002

AbstractMotivated by recent experiments (Spontak, R. J.; Smith, S. D. J Polym Sci Part B: Polym Phys 2001, 39, 947) on morphological and mechanical properties of multiblock copolymers (AB)n,we theoretically elucidate the links between microscopically determined properties, such as the bridging fraction of chains, and mechanical properties of these materials. We do this by applying self‐consistent mean‐field theory to determine morphological aspects such as period and interfacial width and calculate the bridging fractions. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 104–111, 2003