bluuebunny/crossref_metadata_2025_split huggingface dataset:
A transition for hybrid integration of suspended stripline and nonradiative dielectric guide
Authors: Pathak Nagendra P. , Koul Shiban K. , Basu Ananjan 
Published: July 2004

AbstractA new transition from suspended stripline (SSL) to nonradiative dielectric (NRD) guide at the Ka‐band is reported. The transition uses a stepped‐impedance probe in close proximity to the NRD guide strip. The performance of the transition as a function of various structural parameters is studied in detail. Extensive simulations and experiments are carried out to optimize the performance of the transition. The fabricated back‐to‐back transition with 69 mm of NRD guide in between shows an insertion loss of <1.2 dB over the 2‐GHz bandwidth. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 79–82, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20380
Erratum: Resonance characteristics of whispering gallery modes in parallel‐plates‐type cylindrical dielectric resonators
Authors: Akay M. Fatih , Prokopenko Yuriy , Kharkovsky Sergey 
Published: July 2004

AbstractThe original article to which this Erratum refers was published in Microwave Opt Technol Lett (2004) 40(2) 96–101 Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20384
Model for large strain consolidation with compressible pore fluid
Authors: Fox Patrick J. , Qiu Tong 
Published: July 2004

AbstractA numerical model, called CCPF1 (Consolidation with Compressible Pore Fluid 1), is presented for one‐dimensional large strain consolidation of a saturated porous medium with compressible pore fluid. The algorithm includes all the capabilities of a previous large strain consolidation code, CS2, written for incompressible pore fluid. In addition, fluid density and fluid viscosity are functions of fluid pressure in CCPF1. Generalization of the numerical approach to accommodate these functions requires several modifications to the CS2 method, including phase relationships, intrinsic permeability, pore pressure, fluid potential, and mass flux. Inertial forces are neglected and isothermal conditions are assumed. The development of CCPF1 is first presented, followed by an example that illustrates the effects of pore fluid compressibility on the mechanics of consolidation of saturated porous media. Copyright © 2004 John Wiley & Sons, Ltd.
Warranty costs: An age‐dependent failure/repair model
Authors: Dimitrov Boyan , Chukova Stefanka , Khalil Zohel 
Published: July 2004

AbstractAn age‐dependent repair model is proposed. The notion of the “calendar age” of the product and the degree of repair are used to define the virtual age of the product. The virtual failure rate function and the virtual hazard function related to the lifetime of the product are discussed. Under a nonhomogeneous Poisson process scenario the expected warranty costs for repairable products associated with linear pro‐rata, nonrenewing free replacement and renewing free replacement warranties are evaluated. Illustration of the results is given by numerical and graphical examples. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004.
Critical signaling events during the aminoglycoside‐induced death of sensory hair cells in vitro
Authors: Matsui Jonathan I. , Gale Jonathan E. , Warchol Mark E. 
Published: July 2004

AbstractSensory hair cells undergo apoptosis following exposure to aminoglycoside antibiotics. In neurons, apoptosis is associated with a transient increase in intracellular Ca2+, phosphorylation of the transcription factor c‐Jun, and the release of cytochrome c from mitochondria into the cytosol, which along with other cofactors results in the activation of caspases. To examine the possible role of these events in the survival and death of the sensory receptors of the inner ear, we examined the effects of neomycin treatment on cytoplasmic calcium, activation of c‐Jun‐N‐Terminal kinases (JNKs), cytochrome c release, and caspase‐3 activation in cultured vestibular hair cells. Increased numbers of phospho‐c‐Jun‐labeled hair cells (a downstream indicator of JNK activation) were observed at 3–12 h after neomycin treatment, whereas increased numbers of cells with cytoplasmic cytochrome c were observed at 12–18 h following the onset of neomycin treatment. This was followed by an increase in the number of cells that contained activated caspase‐3 and displayed pyknotic nuclei. Treatment with the general caspase inhibitor BAF did not affect the release of cytochrome c and the number of p‐c‐Jun–labeled cells, but reduced the number of cells with activated caspase‐3 and pyknotic nuclei. In contrast, treatment with CEP‐11004, an indirect inhibitor of the JNK signaling pathway, promoted hair cell survival following neomycin treatment and reduced the number of cells with phosphorylated JNK and c‐Jun, cytoplasmic cytochrome c, and activated caspase 3. These results suggest that JNK activation occurs upstream of the release of cytochrome c and that cytochrome c release precedes caspase activation. Cytochrome c release and JNK activation were also preceded by large changes in cytoplasmic calcium. Cytoplasmic calcium increases may be causally related to the release of cytochrome c, and may also be a potential pathway for activation of JNK in hair cells. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2004
Graft copolymerization of methyl acrylate onto poly(vinyl alcohol) initiated by potassium diperiodatoargentate(III)
Authors: Liu Yinghai , Liu Xiaohui , Liu Yuanwei , Zhang Jinsong , Deng Kuilin , Liu Zhanjun 
Published: July 2004

AbstractThe graft copolymerization of methyl acrylate onto poly(vinyl alcohol) (PVA) using potassium diperiodatoargentate(III) [Ag(III)]–PVA redox system as initiator was studied in an alkaline medium. Some structural features and properties of the graft copolymer were confirmed by Fourier‐transfer infrared spectroscopy, scanning electron microscope, X‐ray diffraction and thermogravimetric analysis. The grafting parameters were determined as a function of concentrations of monomer, initiator, macromolecular backbone (X̄n = 1750, M̄ = 80 000 g mol−1), reaction temperature and reaction time. A mechanism based on two single‐electron transfer steps is proposed to explain the formation of radicals and the initiation profile. Other acrylate monomers, such as methyl methacrylate, ethyl acrylate and n‐butyl acrylate, were also used to produce graft copolymerizations. It has been confirmed that grafting occurred to some degree. Thermogravimetric analysis was performed in a study of the moisture resistance of the graft copolymer. Copyright © 2004 Society of Chemical Industry
Structure and reactions of the peroxy radicals of glycine and alanine in peptides: an ab initio study
Authors: Huang Mei Lan , Rauk Arvi 
Published: July 2004

AbstractAb initio calculations at the B3LYP/6‐31G(d) and CBS‐RAD level were carried out to investigate the reaction of αC‐centered peroxy radicals of neutral, non‐zwitterionic glycine and alanine (AH), and as residues in model peptides, N‐formylglycinamide and N‐formylalaninamide (PH). Bond dissociation enthalpies (BDEs) were calculated for the αC—O (D), O—O (DOO) and O—H (DOH) bonds of glycine and alanine peroxy radicals (AOO, POO) and hydroperoxides (AOOH, POOH). The predicted BDEs at 298 K, in kJ mol−1 are AOO(Gly), D = 70; AOO(Ala), D = 69; POO(Gly), D = 89; POO(Ala), D = 86; AOOH(Gly), D = 237, DOO = 203, DOH = 371; AOOH(Ala), D = 234, DOO = 195, DOH = 368; POOH(Gly), D = 266, DOO = 207, DOH = 380; POOH(Ala), D = 264, DOO = 208, DOH=383. Values of BDE of the peptides in β‐sheet peptide conformations were also estimated by constraining the Ramachandran dihedral angles, Φ and Ψ to, values of −150° and +150°: (S)‐POO(Gly), D = 99; (R)‐POO(Gly), D = 78; (S)‐POO(Ala), D = 88; (R)‐POO(Ala), D = 83; (S)‐POOH(Gly), D = 258, DOO = 195, DOH = 362; (R)‐POOH(Gly), D = 278, DOO = 217, DOH = 404; (S)‐ POOH(Ala), D = 240, DOO = 192, DOH = 355; (R)‐POOH(Ala), D = 270, DOO = 204, DOH = 390. The reactions of αC‐peroxy radicals, POO, and αC‐alkoxy radicals, PO, were studied in detail. Copyright © 2004 John Wiley & Sons, Ltd.
Diffusion, evaporation, and surface enrichment of a plasticizing additive in an annealed polymer thin film
Authors: Smith Gregory S. , Skidmore Cary B. , Howe Philip M. , Majewski Jaroslaw 
Published: July 2004

AbstractWe present the first measurements of the simultaneous diffusion, surface enhancement, and evaporation of a plasticizer from a polymer, thin‐film matrix using neutron reflection techniques. The reflectivity profiles as a function of the annealing time at an elevated temperature yield the time‐dependent, plasticizer volume fraction profiles in a polyester–polyurethane (Estane) film. Thin, plasticizer‐enriched layers form at both the polymer/substrate and polymer/air interfaces for annealed and unannealed samples. The diffusion equations for a material diffusing through a film and then evaporating into a vacuum at the free surface describe the loss of the plasticizer from the film for annealed samples. The loss of the plasticizer from the film is not limited by the movement of the plasticizer through the polymer matrix but is dominated by the plasticizer's rate of evaporation from the surface. The rate of evaporation and the volume fraction profiles for the plasticizer at the substrate interface are both consistent with surface attractions dominating over bulk attractions between the miscible plasticizer and the polymer. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3258–3266, 2004
Dynamics of thin polymer films: Recent insights from incoherent neutron scattering
Authors: Soles Christopher L. , Douglas Jack F. , Wu Wen‐Li 
Published: July 2004

AbstractIncoherent neutron scattering is presented as a powerful tool for interpreting changes in molecular dynamics as a function of film thickness for a range of polymers. Motions on approximately nanosecond and faster timescales are quantified in terms of a mean‐square atomic displacement (〈u2〉) from the Debye–Waller factor. Thin‐film confinement generally leads to a reduction of 〈u2〉 in comparison with the bulk material, and this effect becomes especially pronounced when the film thickness approaches the unperturbed dimensions of the macromolecule. Generally, there is a suppression (never an enhancement) of 〈u2〉 at temperatures T above the bulk calorimetric glass‐transition temperature (Tg). Below Tg, the reduction in the magnitude of 〈u2〉 depends on the polymer and the length scales being probed. Polymers with extensive segmental or local mobility in the glass are particularly susceptible to reductions of 〈u2〉 with confinement, especially at the Q vectors probing these longer length scales, whereas materials lacking these sub‐Tg motions are relatively insensitive. Moreover, a reduced 〈u2〉 value correlates with reduced mobility at long time and spatial scales, as measured by diffusion in these thin polymer films. Finally, this reduced thin‐film mobility is not reliably predicted by thermodynamic assessments of an apparent Tg, as measured by discontinuities or kinks in the T dependence of the thermal expansion, specific volume, index of refraction, specific heat, and so forth. These measurements illustrate that 〈u2〉 is a powerful and predictive tool for understanding dynamic changes in thin polymer films. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3218–3234, 2004
Real‐time neutron reflectivity study of the early stages of diffusion into and dissolution of glassy polymers
Authors: Bucknall D. G. , Higgins J. S. , Butler S. A. 
Published: July 2004

AbstractThe early stages of the penetrant behavior of a series of phthalate plasticizers into thin films of glassy, high‐molecular‐weight deuterated poly(methyl methacrylate) (dPMMA) have been studied with in situ real‐time neutron reflectivity. After an initial induction phase, both dioctyl phthalate and diisononyl phthalate penetrate the dPMMA films, as indicated by an increase in the thickness. In both cases, a fast linear rate of swelling of the polymer is followed by another behavior that is much slower. The slowdown in the velocity of the plasticizers at or near the transition point is assumed to occur because of a balancing of the misfit‐induced pressure and the osmotic pressure, which is responsible for the initial plasticizer ingress. In contrast, and unexpectedly, lower molecular weight dibutyl phthalate does not swell dPMMA, but after an initial induction period, the polymer film begins to dissolve. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3267–3281, 2004
Small‐angle neutron scattering studies of dynamics and hierarchical pattern formation in binary mixtures of polymers and small molecules
Authors: Hashimoto Takeji 
Published: July 2004

AbstractWe present the dynamics of the composition fluctuations and pattern formation of two‐component systems in both single‐phase and two‐phase states as studied by time‐resolved small‐angle neutron scattering and light scattering. Two‐component systems to be covered here include not only dynamically symmetric systems, in which each component has nearly identical self‐diffusion coefficients, but also dynamically asymmetric systems, in which each component has different self‐diffusion coefficients. We compare the dynamic behaviors of the two systems and illuminate their important differences. The scattering studies presented for dynamically asymmetric systems highlight that stress–diffusion coupling and viscoelastic effects strongly affect the dynamics and pattern formation. For dynamically symmetric systems, we examine the universality existing in both polymer systems and small‐molecule systems as well as new features concerning the time evolution of hierarchical structures during phase separation via spinodal decomposition over a wide range of wave numbers (up to four orders of magnitude). For both systems, we emphasize that polymers provide good model systems for studying the dynamics and pattern formation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3027–3062, 2004
Polaron signatures in the line shape of semiconductor ;intersubband transitions: quantum kinetics of the electron–phonon interaction
Authors: Butscher S. , Förstner J. , Waldmüller I. , Knorr A. 
Published: July 2004

AbstractWe present a theory of the optical line shape of coherent intersubband transitions in a semiconductor quantum well, considering non‐Markovian LO‐phonon scattering as major broadening mechanism. We show that a quantum kinetic approach leads to additional polaron resonances and a resonance enhancement for gap energies close to the phonon energy. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Design evolution of the trinity college IGVC robot ALVIN
Authors: Bovard Michelle , Gillette Matthew , de Lanerolle Trishan , Marinkovic Bozidar , Trinh Nhon H. , Votto Peter , Ahlgren David J. , Nepal Kundan , Tamrakar Amir 
Published: July 2004

AbstractIn this paper we discuss the design and evolution of Trinity College's ALVIN robot, an autonomous ground vehicle that has participated in the Association for Unmanned Vehicle Systems International Intelligent Ground Vehicle Competition (IGVC) since 2000. The paper first discusses the Trinity Robot Study Team, which has been responsible for developing ALVIN. We then illustrate the four generations of ALVIN, focusing on improvements made as the result of performance shortcomings and outright failures. The discussion considers the robot's body design, drive system, sensors, navigation algorithms, and vision systems. We focus especially on the vision and navigation systems developed for Trinity's fourth‐generation IGVC robot, ALVIN IV. The paper concludes with a plan for future work on ALVIN and with a discussion of educational outcomes resulting from the ALVIN project. © 2004 Wiley Periodicals, Inc.
Vision based robotic control
Authors: Atkinson Brian , Duffy Michael C. , Klingensmith Thomas , Grabbe Robert 
Published: July 2004

AbstractThe University of Colorado at Denver robotics society is constructing an autonomous ground vehicle (AGV) capable of accomplishing the Association of Unmanned Vehicle Systems International (AUVSI) competition objectives. The design presented features an engineering focus on a statistical, vision based discrete‐time control system optimized for an exterior robotic vehicle. A simple robust strategy incorporates ultrasonic ranging to make this vehicle capable of negotiating the features presented in the autonomous challenge. © 2004 Wiley Periodicals, Inc.
Transport of dead infant mountain gorillas by mothers and unrelated females
Authors: Warren Ymke , Williamson Elizabeth A. 
Published: July 2004

AbstractThis report describes prolonged carriage of the corpses of two mountain gorilla infants by both related and unrelated adult females. Two hypotheses regarding this transport are considered: 1) that maternal behavior toward unrelated infants may be a by‐product of the hormonal condition of pregnancy, and 2) that the animals may be “learning to mother,” as nulliparous females could benefit from the experience of handling an infant that is no longer alive. Some factors pertinent to the event of infant deaths in captivity are considered. Zoo Biol 23:375–378, 2004. © 2004 Wiley‐Liss, Inc.
Survey of the reproductive cyclicity status of Asian and African elephants in North America
Authors: Brown Janine L. , Olson Deborah , Keele Mike , Freeman Elizabeth W. 
Published: July 2004

AbstractThe Asian and African elephant populations in North America are not self‐sustaining, and reproductive rates remain low. One problem identified from routine progestagen analyses is that some elephant females do not exhibit normal ovarian cycles. To better understand the extent of this problem, the Elephant TAG/SSP conducted a survey to determine the reproductive status of the captive population based on hormone and ultrasound evaluations. The survey response rates for facilities with Asian and African elephants were 81% and 71%, respectively, for the studbook populations, and nearly 100% for the SSP facilities. Of the elephants surveyed, 49% of Asian and 62% of African elephant females were being monitored for ovarian cyclicity via serum or urinary progestagen analyses on a weekly basis. Of these, 14% of Asian and 29% of African elephants either were not cycling at all or exhibited irregular cycles. For both species, ovarian inactivity was more prevalent in the older age categories (>30 years); however, acyclicity was found in all age groups of African elephants. Fewer elephant females (∼30%) had been examined by transrectal ultrasound to assess reproductive‐tract integrity, and corresponding hormonal data were available for about three‐quarters of these females. Within this subset, most (∼75%) cycling females had normal reproductive‐tract morphologies, whereas at least 70% of noncycling females exhibited some type of ovarian or uterine pathology. In summary, the survey results suggest that ovarian inactivity is a significant reproductive problem for elephants held in zoos, especially African elephants. To increase the fecundity of captive elephants, females should be bred at a young age, before reproductive pathologies occur. However, a significant number of older Asian elephants are still not being reproductively monitored. More significantly, many prime reproductive‐age (10–30 years) African females are not being monitored. This lack of information makes it difficult to determine what factors affect the reproductive health of elephants, and to develop mitigating treatments to reinitiate reproductive cyclicity. Zoo Biol 23:309–321, 2004. © 2004 Wiley‐Liss, Inc.
The effects of transport stress on tiger physiology and behavior
Authors: Dembiec Daniel P. , Snider Richard J. , Zanella Adroaldo J. 
Published: July 2004

AbstractTigers are often transported for education, conservation, and zoo enhancement purposes, however the effect of transfer on them has not yet been documented. Our objective was to evaluate how transport affects the behavior and physiology of tigers, taking into account previous experience with the transport procedure. We simulated transport by relocating five tigers in a small individual transfer cage. Two tigers had prior experience with the procedure, and three tigers were naïve to it. After 30 min, each tiger was released back into their original enclosure. Physiological measurements were recorded for four of the five tigers; these included respiration rate and immune‐reactive fecal cortisol response using radioimmunoassay. We also recorded the behavior of all five tigers before, during, and after transport. Our behavioral analysis included activity level, pacing behavior, time spent investigating, respiration rate, and ear position. Average respiration rates of all tigers increased from 56.1 breaths/min to 94.6 breaths/min during transport and to 132.3 breaths/min 10 min following release into their enclosures. Average immune‐reactive cortisol concentrations peaked 3–6 days after transport at 239% above baseline and returned to baseline levels 9–12 days afterward. During their peak time block, naïve tigers exhibited a higher average increase in cortisol levels (482% above baseline) than the experienced tigers (158% above baseline). The naïve tigers' average immune‐reactive cortisol concentration remained elevated for a longer period (9–12 days) than the experienced tigers' (3–6 days). In both groups, behavioral responses ranged from active to inactive, however naïve tigers performed these repertoires with greater intensity by pacing faster and performing fewer state changes. Results suggest that prior exposure to elements of the transport procedure may lead to some level of habituation, thus reducing the effects of transportation stress. Zoo Biol 23:335–346, 2004. © 2004 Wiley‐Liss, Inc.
Interactions between red‐billed oxpeckers and black rhinos in captivity
Authors: McElligott Alan G. , Maggini Ivan , Hunziker Lorenz , König Barbara 
Published: July 2004

AbstractThe relationship between oxpeckers and African ungulates has traditionally been considered mutualistic, because the birds were thought to reduce the tick loads of their hosts. However, recent field studies have questioned the validity of this assumption. Red‐billed oxpeckers were found to have no impact on the number of ticks living on domestic cattle and they also prolonged the healing time of wounds (Weeks [1999] Anim Behav 58:1253–9; Weeks [2000] Behav Ecol 11:154–60). One of the important limitations of these studies is the fact that the two species did not coevolve, and therefore the results may not be representative of the relationships between oxpeckers and their native African ungulate hosts in general. We carried out observations between red‐billed oxpeckers and one of their natural host species, the black rhino, in captivity, to investigate their relationship. We found that the rhinos had oxpeckers present on them for almost half (approximately 45%) the time that the two species were in the same enclosure. The oxpeckers spent a large proportion (approximately 40%) of their time on the rhinos foraging, and mostly at wounds. We observed oxpeckers opening wounds on their hosts for the first time; they created four new wounds on the female rhino and nine on the male. Although the rhinos were intolerant of the presence of the oxpeckers at wounds, only approximately 43% of their attempts at removal were successful. Therefore if oxpeckers are housed with any of their native hosts in captivity, observations should be carried out to determine the activities of the oxpeckers on those hosts. Zoo Biol 23:347–354, 2004. © 2004 Wiley‐Liss, Inc.