bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthetic peptides as cancer vaccines
Authors: Sundaram Roshni , Dakappagari Naveen K. , Kaumaya Pravin T. P.
Published: October 2002

Effective cancer therapy or prevention has been the dream of physicians and scientists for many years. Although we are still very far from our ultimate goal of cancer prevention, significant milestones have been realized in terms of our knowledge base and understanding of the pathogenesis of cancerous cells and the involvement of the immune system against both self‐ and virus‐associated tumor antigens. Immunotherapeutic strategies are now accepted to being superior in terms of the exquisite specificity that they offer in targeting only tumor cells as opposed to the existent chemotherapy or radiation therapy that is more general and invasive with many associated side effects. There are several immunotherapeutic strategies that are currently under investigation. This review primarily focuses on the significant advances made in the use of synthetic peptides in the development of subunit cancer vaccines. We have attempted to highlight some of the fundamental issues regarding antigen processing and presentation, Major Histocompatibility Complex (MHC) restriction, T‐cell help, structural determinants in antibody recognition, and the use of these concepts in the rational design and delivery of peptide vaccines to elicit protective humoral and cell mediated immune responses. The recent use of costimulatory molecules and cytokines to augment immune responses also has been discussed along with the contributions of our laboratory to the field of synthetic peptide vaccine development. © 2002 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 66: 200–216, 2002
P2P‐R protein overexpression restricts mitotic progression at prometaphase and promotes mitotic apoptosis
Authors: Gao Sizhi , Scott Robert E.
Published: October 2002

Mitotic cells show a tenfold increase in immunoreactive P2P‐R protein. During mitosis, the distribution of P2P‐R protein also changes from a primary nucleolar localization in interphase cells to the periphery of chromosome in mitotic cells. These findings suggest that P2P‐R might serve a functional role in mitosis. To test this possibility, human Saos2 cells were stably transfected with P2P‐R DNA constructs and the biological effects of P2P‐R overexpression were evaluated. Overexpression of near full‐length P2P‐R was found to have paradoxical effects on the relationship between proliferation and mitosis in the nine Saos2 cell clones that were studied. A significant repression in the population doubling rates was observed in all nine clones even though a significant increase in the frequency of easily detached cells with a mitotic morphology was apparent. Flow cytometric analysis confirmed that greater than two thirds of the cells with a mitotic morphology had a 4n DNA content. Confocal microscopy further established that 85% of the mitotic cell population had prometaphase characteristics suggesting that P2P‐R overexpression restricts mitotic progression at prometaphase. Many cells with a mitotic morphology also showed signs of apoptosis with prominent cell surface blebs. Confocal microscopy confirmed that 25–40% of such mitotic cells were apoptotic with chromosomal abnormalities and cell surface blebbing. In association with mitotic apoptosis, P2P‐R protein appears to dissociate from the periphery of chromosomes and localize in the cytoplasm and in cell surface blebs. The presence of P2P‐R in cell surface blebs was confirmed by analysis of highly enriched populations of apoptotic cell surface blebs wherein Western blotting documented the presence of 250 kDa P2P‐R. These results therefore suggest that P2P‐R overexpression promotes both prometaphase arrest in mitosis and mitotic apoptosis. © 2002 Wiley‐Liss, Inc.
Hydrostatic fluid pressure enhances matrix synthesis and accumulation by bovine chondrocytes in three‐dimensional culture
Authors: Mizuno Shuichi , Tateishi Tetsuya , Ushida Takashi , Glowacki Julie
Published: October 2002

Monolayer cell cultures and cartilage tissue fragments have been used to examine the effects of hydrostatic fluid pressure (HFP) on the anabolic and catabolic functions of chondrocytes. In this study, bovine articular chondrocytes (bACs) were grown in porous three‐dimensional (3‐D) collagen sponges, to which constant or cyclic (0.015 Hz) HFP was applied at 2.8 MPa for up to 15 days. The effects of HFP were evaluated histologically, immunohistochemically, and by quantitative biochemical measures. Metachromatic matrix accumulated around the cells within the collagen sponges during the culture period. There was intense intracellular, pericellular, and extracellular immunoreactivity for collagen type II throughout the sponges in all groups. The incorporation of [35S]‐sulfate into glycosaminoglycans (GAGs) was 1.3‐fold greater with constant HFP and 1.4‐fold greater with cyclic HFP than in the control at day 5 (P < 0.05). At day 15, the accumulation of sulfated‐GAG was 3.1‐fold greater with constant HFP and 2.7‐fold with cyclic HFP than the control (0.01). Quantitative immunochemical analysis of the matrix showed significantly greater accumulation of chondroitin 4‐sulfate proteoglycan (C 4‐S PG), keratan sulfate proteoglycan (KS PG), and chondroitin proteoglycan (chondroitin PG) than the control (P < 0.01). With this novel HFP culture system, 2.8 MPa HFP stimulated synthesis of cartilage‐specific matrix components in chondrocytes cultured in porous 3‐D collagen sponges. J. Cell. Physiol. 193: 319–327, 2002. © 2002 Wiley‐Liss, Inc.
Are there gap junctions between chief (glomus, type I) cells in the carotid body chemoreceptor? A review
Authors: Kondo Hisatake
Published: October 2002

Since the dye‐ and electronic couplings between the carotid body chief cells have been demonstrated, the detection and localization of the gap junctions in the carotid body is crucial to understanding the functional mechanism of chemoreception. However, conventional electron microscopy has been unsuccessful in unquestionably detecting ultrastructural features equivalent to the gap junctions, such as close (2 nm in width) membrane appositions in ultrathin sections and aggregations of intramembranous particles in freeze‐fracture replicas of the carotid body. We previously reported using a modified electron microscopic study by chemically fixed and subsequent rapid freezing and freeze‐substitution method a number of close membrane appositions comparable to the gap junctions. However, we later found that the freeze‐substitution also induces numerous close apposition of the membrane in sites where the gap junctions are not known to occur, indicating that the modified electron microscopy by freeze‐substitution is not always confirmative in the detection of the gap junction. With regard to the molecular evidence for the gap junction in the carotid body, there have so far been few data on the immunohistochemical demonstration on connexin 32 and 43 in cultured chief cells, but not in the in situ cells. Microsc. Res. Tech. 59:227–233, 2002. © 2002 Wiley‐Liss, Inc.
Characteristics of disturbances in the laminar–turbulent transition of spherical Couette flow. 1. Spiral Taylor–Görtler vortices and traveling waves for narrow gaps
Authors: Nakabayashi Koichi , Tsuchida Yoichi , Zheng Zhiming
Published: October 2002

The fundamental frequencies of velocity fluctuations caused by disturbances (vortices and waves) in the laminar–turbulent transition of spherical Couette flow between two concentric spheres with only the inner sphere rotating are investigated by simultaneous and flow-visualization measurements for two small ratios, 0.06 and 0.024, of the clearance to inner-sphere radius for which spiral Taylor–Görtler (TG) vortices and traveling waves on TG vortices play an important role. As the Reynolds number Re is increased for both clearance ratios, first toroidal TG vortices occur at the equator, but the flow is steady. Second, spiral TG vortices (fundamental frequency fSi) occur next to the toroidal ones, so that the flow becomes singly periodic. Third, in addition to these spiral TG vortices, new spiral TG vortices occur between them at the different colatitude θ, so that the pair number of spiral TG vortices around the spherical annulus differs by θ. Therefore, plural fundamental frequencies fSi (i=1,2,…) of spiral TG vortices are detected, corresponding to the different pair numbers. However, the flow is not quasi-periodic, because ratios of the different frequencies fSi are in rational. Fourth, traveling waves (fundamental frequency fW) occur on TG vortices, so that the flow becomes quasi-periodic (fSi and fW). Fifth, the plural frequencies fSi change to a broadband frequency fB, which indicates the onset of chaos. Sixth, fW disappears, so that the flow becomes chaotic spiral TG vortex-flow with only fB. The rotation frequency (wave speed) of traveling waves is larger than that of spiral TG vortices, and the value of fB exists about between the two rotation frequencies.
Computation of supersonic mixing layers
Authors: Kourta A. , Sauvage R.
Published: October 2002

Direct numerical simulation is used to investigate three-dimensional temporal supersonic mixing layers at two convective Mach numbers 1.2 and 1.6. At the convective Mach number of 1.2, the compressibility effects, characterized by the shear layer growth rate reduction, are more pronounced than at high subsonic convective Mach numbers. In this case, the flow structure becomes three dimensional, and Λ structures are clearly observed which accelerate the occurrence of turbulence. For the Mc=1.2 case, the absence of symmetry leads to a strong interaction between Λ structures. At Mc=1.6, the use of a computational box size of one fundamental wavelength maintains the symmetry of the flow. The Λ structures, strongly inclined, are distorted by the shear layer and split into two symmetrical parts. Finally, shocklets occur in the flow for both convective Mach numbers. These viscous shocks are developed in three dimensions and are stronger for the 1.6 case. In this paper, transition mechanisms are analyzed and the existence of shocklets and their influences are studied.
Application of the integral encounter theory to the description of degenerate electron exchange reactions
Authors: Doktorov A. B. , Ivanov K. L. , Lukzen N. N. , Morozov V. A.
Published: October 2002

Consistent kinetic description of degenerate electron exchange (ion-molecular charge transfer) reaction in the liquid phase based on the encounter theory has been performed. This has made it possible to allow for re-encounters of reactants and the attendant additional dephasing of electron spin during the encounter. The applicability range of the approximation of noncorrelated spectral migration that is commonly used to describe spectroscopic manifestation of degenerate electron exchange in strong magnetic fields has been refined. It is shown that for radicals with large hyperfine interaction constants the discrepancy between the results obtained, and the approximation of noncorrelated frequency migration may be considerable.
H-atom high-n Rydberg time-of-flight spectroscopy of C–H bond fission in acrolein dissociated at 193 nm
Authors: Parsons B. F. , Szpunar D. E. , Butler L. J.
Published: October 2002

The experiments presented in this work use H-atom high-n Rydberg time-of-flight spectroscopy to measure the H-atom velocity distribution from one- and multiple-photon dissociation processes in acrolein following excitation at 193 nm. The one-photon H-atom signal is dominated by primary C–H bond fission in acrolein. We compare some of the qualitative features of the recoil translational energy distribution for the observed H atoms with what would be expected based on theoretical results for aldehydic C–H bond fission on the ground and lowest singlet and triplet excited states and conclude that the dissociation cannot proceed through either of these paths. A possible dissociation mechanism is proposed to account for the observed P(ET) that is consistent with the observation of an isotropic dissociation. Finally, we report results on methyl vinyl ketone photodissociation which provide evidence that the primary C–H bond fission process in acrolein is fission of the aldehydic bond.
Imaging O(3P)+alkane reactions in crossed molecular beams: Vertical versus adiabatic H abstraction dynamics
Authors: Liu Xianghong , Gross Richard L. , Hall Gregory E. , Muckerman James T. , Suits Arthur G.
Published: October 2002

We present a crossed molecular beam study of the reaction of O(3P) with alkanes, using velocity map imaging of the alkyl radical product via single photon ionization at 157 nm. We obtained the differential cross sections and translational energy distributions for reaction of O(3P) with cyclohexane, n-butane and isobutane at a range of well-defined collision energies from 4.7 to 14.8 kcal/mol. The product alkyl radicals are largely backscattered with respect to the alkane beam at all collision energies, but the scattering distribution is clearly broadened with increasing collision energy. This is consistent with a picture of direct rebound dynamics but inconsistent with a recent result for the vibrationally excited OH component [H. Tsurumaki et al., J. Chem Phys. 112, 8338 (2000)], and we explore the source of this inconsistency. More surprising is the large fraction of the available energy partitioned into internal degrees of freedom of the alkyl radical, showing that the simple triatomic picture of the reaction is inadequate to account for all of the observations. To explain the observed dynamics we propose a modification of the triatomic model in which the exoergicity is adjusted to reflect “vertical” rather than “adiabatic” H abstraction energetics, and this picture is supported by ab initio calculations and by detailed consideration of the translational energy release patterns.
Stability of flow in a channel with vibrating walls
Authors: Floryan J. M. , Szumbarski J. , Wu X.
Published: October 2002

The effects of small wall vibrations in the form of traveling waves on the asymptotic stability of a channel flow are analyzed. It is shown that vibrations may affect flow instability only if they consist of modes with wavelength and frequency close to those of the neutral Tollmien–Schlichting (TS) waves. Vibrations in resonance with the neutral TS waves produce instability that amplifies linearly in time. It is shown that vibrations detuned with the neutral TS waves may lead to an initial transient growth linear in time. It is further demonstrated that this growth may lead to flow destabilization through nonlinear effects, resulting in a significant reduction in the critical Reynolds number. The wealth of possible flow responses for various forms of detuning, including modulated wall vibrations, is also discussed.
Spontaneous orientational order in confined dipolar fluid films
Authors: Klapp S. H. L. , Schoen M.
Published: October 2002

We report Monte Carlo simulation results for a strongly coupled dipolar soft-sphere (DSS) fluid confined to a nanoscopic slit pore with structureless, nonconducting walls. The central topic of our investigation are the conditions under which the pore fluid can spontaneously order into a globally polarized (i.e., ferroelectric) state. Polarized states are observed in bulk DSS fluids at sufficiently low temperatures and high densities/pressures. The confined system is simulated in the (N,Lz,P∥,T) ensemble, where N is the particle number, Lz the wall separation, P∥ the pressure parallel to the walls, and T the temperature. Fixing T and P∥ such that the corresponding bulk system is ferroelectric, and considering confined films with various thicknesses proportional to Lz, we first demonstrate that the long-range orientational order persists down to Lz≈6σ. We then specialize to the case Lz=7σ, for which we investigate in detail the spatial and orientational structure as functions of P∥. It turns out that the transition from the globally isotropic to the globally polarized phase occurs at significantly lower pressures/densities than in the bulk, indicating that spatial confinement can support the onset of ferroelectric order. We explain this phenomenon within the framework of a simple mean-field theory based on the assumption that confinement effectively restricts orientational fluctuations, as suggested by the Monte Carlo results.
Nondispersive hole transport in a spin-coated dendrimer film measured by the charge-generation-layer time-of-flight method
Authors: Markham Jonathan P. J. , Anthopoulos Thomas D. , Samuel Ifor D. W. , Richards Gary J. , Burn Paul L. , Im Chan , Bässler Heinz
Published: October 2002

Measurements of the mobility of a first-generation (G1) bis-fluorene cored dendrimer have been performed on spin-coated samples of 500 nm thickness using the charge-generation-layer time-of-flight (TOF) technique. A 10 nm perylene charge generation layer was excited by the 532 nm line of a Q-switched Nd:YAG laser and the generated carriers swept through the dendrimer film under an applied field. We observe nondispersive hole transport in the dendrimer layer with a room-temperature mobility μ=2.0×10−4 cm2/V s at a field of 0.55 MV/cm. There is a weak field dependence of the mobility and it increases from μ=1.6×10−4 cm2/V s at 0.2 MV/cm to μ=3.0×10−4 cm2/V s at 1.4 MV/cm. These results suggest that the measurement of mobility by TOF in spin-coated samples on thickness scales relevant to organic light-emitting diodes can yield valuable information, and that dendrimers are promising materials for device applications.
Microstructure of GaAs/GaN interfaces produced by direct wafer fusion
Authors: Jasinski J. , Liliental-Weber Z. , Estrada S. , Hu E.
Published: October 2002

Results of a transmission electron microscopy (TEM) study of directly bonded GaAs/GaN structures obtained by wafer fusion are presented. A large fraction of the interface area was found to be well bonded, with the presence of a thin (1–2 nm) amorphous layer of a native oxide at the bonded interface. The dominant defects found in nonbonded areas were cavities elongated along the [110]GaAs direction. Plan-view TEM study of well-bonded regions showed the presence of two dislocation networks. The first, formed at the interface to accommodate an unintentional tilt between the fused crystals, consists of a one-dimensional array of wavy dislocations located at interface steps. The second dislocation network, formed to relieve additional strain from the thermal processing of the samples, consists of a two-dimensional, irregularly spaced grid of dislocations formed on the GaAs side that runs parallel to either the [110]GaAs or [11_0]GaAs directions.
A possible mechanism for enhanced electrofluorescence emission through triplet–triplet annihilation in organic electroluminescent devices
Authors: Ganzorig Chimed , Fujihira Masamichi
Published: October 2002

We demonstrate here that luminance increased more than linearly with an increase in current density of tris(8-hydroxyquinoline) aluminum (Alq3)-based electroluminescent (EL) devices and the EL efficiency reached ∼5 cd A−1 at 250 mA cm−2 when electron and hole injection was well balanced. The luminance–current curves were well fitted with a combination of a linear and a quadratic function of the current. The quadratic component can be attributed to additional singlet excited state (1Alq3*) formation through triplet–triplet (T–T) annihilation of triplet excited states (3Alq3*). The requirement of the well-balanced charge injection implies that the long-lived A4lq3* was quenched efficiently by energy transfer to excess and colored Alq3−⋅ anion or Alq3+⋅ cation radicals in the emission zone when the charge injection was unbalanced. The short-lived A3lq3* was not quenched appreciably.
Filamentation and linewidth enhancement factor in InGaAs quantum dot lasers
Authors: Smowton P. M. , Pearce E. J. , Schneider H. C. , Chow W. W. , Hopkinson M.
Published: October 2002

We report measurements of the near-field of broad-area lasers with quantum dot and quantum well active regions designed to emit at 1 μm. The quantum dot devices exhibit less filamentation than comparable quantum well devices, and exhibit a reduction in filamentation as the injection level is increased. This is consistent with a theory that includes the Coulomb coupling between dot and wetting-layer states on a microscopic level. The theory predicts a linewidth enhancement factor from −3 to 1, depending on carrier density and inhomogeneous broadening.
Acoustic chaos and sonic infrared imaging
Authors: Han Xiaoyan , Li Wei , Zeng Zhi , Favro L. D. , Thomas R. L.
Published: October 2002

We describe a quasichaotic mechanism for the generation of complex vibrations from the application of a 450 ms, 40 kHz excitation coupled nonlinearly to a sample under inspection by means of sonic infrared (SIR) imaging. Monitoring the sample vibration by means of a laser vibrometer, we find that the vibration switches from the fundamental and harmonics to several series of frequencies that are rational fractions of the fundamental driving frequency. The transition to this quasichaotic behavior is important in obtaining high-quality SIR images.
A flame surface density based model for large eddy simulation of turbulent nonpremixed combustion
Authors: Zhou Xiangyang , Mahalingam Shankar
Published: October 2002

A combustion model based on the flame surface density (FSD) concept is developed and implemented for large eddy simulation of turbulent nonpremixed combustion of wood pyrolysis gas and air. In this model, the filtered reaction rate ω̇̄α of species α is estimated as the product of the consumption rate per unit surface area ṁα and the filtered FSD Σ̄. This approach is attractive since it decouples the chemical problem from the description of the turbulence combustion interaction. The filtered FSD is modeled as the product of the conditional filtered gradient of mixture fraction and the filtered probability density function. This approach is validated from direct numerical simulation (DNS) using spatial filtering operation. Results show that the proposed FSD model provides a good description for the filtered reaction rate of wood pyrolysis gas. Temperature predicted by large eddy simulation agrees well with that filtered from DNS data.
Enhanced dissipation of short gravity and gravity capillary waves due to parasitic capillaries
Authors: Zhang Xin
Published: October 2002

The dissipation rate of short, mechanically generated, monochromatic surface waves was measured in order to determine the increased dissipation due to the generation of parasitic capillary waves. As the surface waves propagate freely, the decaying wave elevations were measured by an ultra-thin capacitance wire. Measurements indicate that the dissipation rate increases approximately with the square of the wave slope, AK, and the generation of parasitic capillaries depends on the wavelength of the surface waves. The maximum generation of parasitic capillaries coincides with a surface wave wavelength near 7 cm. Measured data fits a simple parameterized model of the dissipation rate reasonably well.
A remarkable mathematical property of the Landé factor in quantum mechanics
Authors: Pfister Albrecht , Pfister Herbert
Published: October 2002

We show that the Landé factor can, in principle, attain any positive or negative rational number.
Measuring the angular solar diameter using two pinholes
Authors: Sigismondi Costantino
Published: October 2002

At the turn of the sixteenth century Tycho Brahe and Johannes Kepler made single pinhole measurements of the solar diameter. Their accuracy was limited by diffraction (unknown to them) and the motion of the image on the screen. We discuss how two pinholes built on the same mask can be used to bypass all the problems inherent in the single pinhole approach. The distance at which the two images of the Sun are in contact is the only measurement needed, and the experimental accuracy is much better than measuring the diameter of a single moving image. We obtained 0.5% accuracy, sufficient to follow the angular variations of the solar diameter due to the motion of the Earth in its orbit.
Grip-slip behavior of a bouncing ball
Authors: Cross Rod
Published: October 2002

Measurements of the normal reaction force and the friction force acting on an obliquely bouncing ball were made to determine whether the friction force acting on the ball is due to sliding, rolling, or static friction. At low angles of incidence to the horizontal, a ball incident without spin will slide throughout the bounce. At higher angles of incidence, elementary bounce models predict that the ball will start to slide, but will then commence to roll if the point of contact on the circumference of the ball momentarily comes to rest on the surface. Measurements of the friction force and ball spin show that real balls do not roll when they bounce. Instead, the deformation of the contact region allows a ball to grip the surface when the bottom of the ball comes to rest on the surface. As a result the ball vibrates in the horizontal direction causing the friction force to reverse direction during the bounce. The spin of the ball was found to be larger than that due to the friction force alone, a result that can be explained if the normal reaction force acts vertically through a point behind the center of the ball.
ON THE MEASUREMENT OF THE PHASE DISTRIBUTION OF FIELD STATES
Authors: VALVERDE C. , BASEIA B. , MALBOUISSON J. M. C.
Published: October 2002

A proposal for measuring the phase distribution P(θ) of certain families of field states is presented. This method is based on establishing the connection between the phase distribution and the visibility of the (single-photon) interference in a Mach–Zehnder device. Such a scheme can also be applied to determine relative phases of superposed states.
Relative messenger RNA expression profiling of collagenases and aggrecanases in human articular chondrocytes in vivo and in vitro
Authors: Bau Brigitte , Gebhard Pia M. , Haag Jochen , Knorr Thomas , Bartnik Eckart , Aigner Thomas
Published: October 2002

Objective

Osteoarthritic (OA) cartilage destruction depends on collagen‐ and aggrecan‐degrading proteases such as collagenases (MMP‐1 and MMP‐13), stromelysin (MMP‐3), MMP‐14, as well as the so‐called aggrecanases (ADAM‐TS4 and ADAM‐TS5). In this study, we tried to clarify whether these proteases are expressed in vivo in human normal and OA cartilage (and whether they are up‐regulated or down‐regulated during the disease process) and in interleukin‐1β (IL‐1β)–stimulated chondrocytes in vitro.

Methods

Quantitative polymerase chain reaction assays were developed and performed on RNA isolated directly from normal and degenerative cartilage tissue as well as from primary human articular chondrocytes cultured with and without IL‐1β.

Results

In vivo, MMP‐1 was detectable only at very low levels in any condition. MMP‐13 expression was low in normal and early degenerative cartilage but was strongly up‐regulated in late‐stage OA specimens. MMP‐1 and MMP‐13 were expressed much higher in vitro than in vivo and were up‐regulated by IL‐1β. Among all proteases, MMP‐3 was by far the most strongly expressed, although it was strongly down‐regulated in late‐stage OA specimens. Expression of MMP‐3 was higher in vitro than in vivo and was up‐regulated by IL‐1β. ADAM‐TS5 and MMP‐14 were expressed in all sample groups. Expression of ADAM‐TS4 was very low in vivo and was induced in vitro after stimulation by IL‐1β.

Conclusion

Our expression data clearly support MMP‐13 as the major collagenase in OA cartilage. The most strongly expressed aggrecanase was ADAM‐TS5. ADAM‐TS4 was expressed only at a very low level in normal cartilage and was only slightly up‐regulated in OA cartilage, casting doubt on this enzyme being the relevant aggrecanase of articular cartilage. Results of our study show that expression of many enzymes is significantly different in vitro and in vivo and suggest that IL‐1β stimulation of articular chondrocytes might not be a good model for the matrix catabolism in OA cartilage.
MAC over ATM group communication system
Authors: Hayase Kazuyoshi , Irie Kazunari , Ohta Norihisa
Published: October 2002

The authors propose a regional information network system that provides communications among the group members using personal computers (PC). In order to cope with the future requirements for high‐speed communication, there must be a system that can achieve diversified communication rates and accommodate a large number of users. From such a viewpoint, this paper considers the composition of a new system based on the MAC over ATM scheme. As the first step, systems based on existing techniques are presented: a system (MAC terminating system) to which the transition from the STM system is easy, and a system (LANE system) based on the LAN emulation standard. Then, a new system (BC‐VC) is proposed, in which the processing in the center is realized only by the ATM layer. Those systems are compared and examined by simulation, and it is shown that the BC‐VC system is better than the other systems when there is a large number of groups. Furthermore, the design of an experimental system based on the BC‐VC scheme is shown, together with the results of performance evaluation experiments. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(2): 61–70, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1154
Calculation of normalized impedance of a transversal slot on the image plate of an image NRD guide using the method of moments
Authors: Ishii Nozomu , Itoh Kiyohiko
Published: October 2002

The normalized impedance of a transverse slot on the image plate of an image NRD that is a modification of the original NRD is formulated by means of the method of moments. In terms of the modes that can be supported within the image NRD guide, the electromagnetic field inside the guide is modally expanded and the dyadic Green's function (DGF) is obtained. In addition, by applying the concept of the virtual cavity method, the DGF is modified. The numerical results are compared with the experimental data obtained by the standing wave measurement method. The difference in the resonant frequency is 1.6% and a shift of the peak value is observed. Nevertheless, the tendencies of the frequency locus are identical. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(2): 71–79, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1155
Analysis and simulation of received signal level distribution in wide‐band mobile radio channels
Authors: Yan Jiang , Kozono Shigeru
Published: October 2002

This paper considers the propagation model in which the amplitude of the direct wave is kept constant and that of the indirect wave exhibits Rayleigh fluctuations in the line‐of‐sight and non‐line‐of‐sight channels. The instantaneous received signal level distribution is examined by computer simulation and a fading simululator, with the equivalent received bandwidth (product of received bandwidth 2Δf and maximum path length difference ΔLmax) as the propagation parameter. It is seen that the equivalent received bandwidth is suited as a parameter to represent the instantaneous received signal level distribution. The instantaneous received signal level distributions derived by the computer simulation and the fading simulator agree well. Conventional narrow‐band transmission corresponds to the case in which 2ΔfΔLmax is less than 10 MHz‐m. Then, the fading depth is determined by the power ratio a between the direct wave and the indirect wave. Wide‐band transmission corresponds to the case in which 2ΔfΔLmax is larger than 10‐MHz‐m. Then, the fading depth is determined by a and 2ΔfΔLmax, becoming less when those quantities are increased. When 2ΔfΔLmax is very large, the fading depth also depends on the number of arriving waves. These properties are derived theoretically and are verified by the simulation and the fading simulator. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(2): 94–105, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1157
Two‐dimensional modelling of ice cover effects for the dynamic analysis of concrete gravity dams
Authors: Bouaanani Najib , Paultre Patrick , Proulx Jean
Published: October 2002

A two‐dimensional numerical model for determining the effects of the presence of an ice cover on the dynamic behaviour of large gravity dams is presented. Analytical predictions are compared to results obtained during a series of extensive dynamic tests on a large gravity dam. Data were obtained during summer and severe winter conditions to investigate the dynamic interactions between the dam, foundation, reservoir and the ice cover. The analysis includes ice‐reservoir interaction as well as the effects of water compressibility, flexible foundation and reservoir bottom absorption. Good agreement with the experimental findings is obtained. Copyright © 2002 John Wiley & Sons, Ltd.
Ascertainment adjustment in complex diseases
Authors: Glidden David V. , Liang Kung‐Yee
Published: October 2002

Genetic studies of complex diseases must confront two statistically difficult issues simultaneously. First, in many settings, to minimize the number of individuals to be genotyped, families enriched for disease must be oversampled. Also, statistical models in family studies should allow for residual association. This association will represent unmeasured genetic and environmental factors influencing disease risk. Dealing with these features simultaneously is both compelling and challenging. Burton et al. [2000] (Am. J. Hum. Gen. 69: 1505–14) recently discussed this issue and suggested that ascertainment corrections may lead to problematic parameter estimation. We revisit the issues and examples of Burton et al. [2000] (Am. J. Hum. Genet. 69: 1505–14) and present a more optimistic assessment. Estimation in this context is conceptually straightforward, but may be more problematic in practice. Specifically, we find that even slight misspecification of the random effects distribution in ascertainment‐adjusted likelihood can yield severely biased parameter estimates. This result should make scientists wary when interpreting results from ascertainment‐adjusted variance‐component models. Genet. Epidemiol. 23:201–208, 2002. © 2002 Wiley‐Liss, Inc.
A fast simulation model combining with artificial neural networks for fin‐and‐tube condenser
Authors: Ding Guo‐liang , Zhang Chun‐lu , Liu Hao
Published: October 2002

In order to improve predicting precision and increase the computation speed of simulation for a fin‐and‐tube condenser, a novel method integrating the fundamental mathematical model with an artificial neural network (ANN) is presented. A three‐zone model is used as the basic mathematical model. An ANN maps the nonlinear relation between the distributed‐parameter model and the three‐zone one. Another ANN is involved in the present model to reflect the bias between the model and experimental results, and to improve the simulation accuracy. Practical utilization of the present model shows that the computation speed of the present model is two orders of magnitude higher than that of the distributed‐parameter model, while the precision is also improved. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(7): 551–557, 2002; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/htj.10054
Heat transfer research on vapor‐gas mixture with condensation in a vertical tube
Authors: Jia L. , Li X.P. , Sun J.D.
Published: October 2002

The convection‐condensation heat transfer of vapor‐gas mixtures in a vertical tube was studied theoretically and experimentally. The effects of the condensation of a small amount of water vapor (8 to 20%) on heat transfer in a vertical tube were discussed. Comparisons show that theoretical solutions obtained through modified film model and experimental results are in good agreement. The results show that the condensation heat transfer of a small amount of water vapor and single‐phase convection heat transfer in the vapor‐gas mixtures are of the same order of magnitude, and these two modes of heat transfer could not be neglected. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(7): 531–539, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10055
A finite line‐source model for boreholes in geothermal heat exchangers
Authors: Zeng H. Y. , Diao N. R. , Fang Z. H.
Published: October 2002

An analytical solution of the transient temperature response in a semi‐infinite medium with a line source of finite length has been derived, which is a more appropriate model for boreholes in geothermal heat exchangers, especially for their long‐duration operation. The steady‐state temperature distribution has also been obtained as a limit of this solution. An erratic approach to this problem that appears in some handbooks and textbooks is indicated. Two representative steady‐state borehole wall temperatures, the middle point temperature and the integral mean temperature, are defined. Differences between them are compared, and concise expressions for both are presented for engineering applications. On this basis the influence of the annual imbalance between heating and cooling loads of the geothermal heat exchangers is discussed regarding their long‐term performance. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(7): 558–567, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10057
Temperature fluctuation in bubble nucleate pool boiling: A proposed new factor of evaporation
Authors: Sekine Ikuhei
Published: October 2002

The phase change rate and related physical constants of superheated water at the liquid surface can be determined by the mechanism of hydrogen bonding and by the Maxwell‐Boltzmann principle. In this paper, we introduce a physical constant and attempted to demonstrate the existence and the value of this physical constant. First, we measured temperature fluctuations under the bubbles in a pool of boiling water. Second, a sample analytical model was introduced, to determine the value of the physical constant. Comparisons were made between the experimental data and those of the calculations. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(7): 578–594, 2002; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/htj.10059
Retinoic acid induces expression of the interleukin‐1β gene in cultured normal human mammary epithelial cells and in human breast carcinoma lines
Authors: Liu Limin , Gudas Lorraine J.
Published: October 2002

Retinoic acid (RA) and its derivatives inhibit the proliferation of normal human mammary epithelial cells (HMEC) and some breast carcinoma lines by mechanisms which are not fully understood. To identify genes that mediate RA‐induced cell growth arrest, an HMEC cDNA library was synthesized and subtractive screening was performed. We identified the interleukin‐1β (IL‐1β) gene as an RA induced gene in HMEC. Northern blot analyses showed that the IL‐1β gene was up‐regulated as early as 2 h after RA treatment. Results from the treatment of HMEC with cycloheximide and actinomycin D indicated that the regulation of the IL‐1β gene by RA occurred at the transcriptional level and that the IL‐1β gene is a direct, downstream target gene of RA. To evaluate the effects of IL‐1β on cell proliferation, the proliferation of HMEC was measured in the presence of RA or IL‐1β, or both. Either RA or IL‐1β could significantly inhibit the proliferation of HMEC. However, the addition of soluble IL‐1 receptor antagonist (sIL‐1ra) to the cell culture medium did not block RA‐induced HMEC growth inhibition, whereas sIL‐1ra did block the growth inhibition of HMEC by IL‐1β. IL‐1β expression was not observed in the three carcinoma cell lines, MCF‐7, MDA‐MB‐231, and MDA‐MB‐468, as compared to the HMEC. Growth curves of the breast carcinoma cell lines showed strong inhibitory effects of RA and IL‐1β on the growth of the estrogen receptor (ER) positive MCF‐7 cell line, but only a small effect on the ER negative MDA‐MB‐231 cells. The expression of the IL‐1β gene was also transcriptionally activated by RA in normal epithelial cells of prostate and oral cavity. Our results suggest that: (a) the IL‐1β gene is a primary target of RA receptors in HMEC; (b) the enhanced expression of the IL‐1β gene does not mediate the RA‐induced growth arrest of HMEC; and (c) the expression of the IL‐1β gene is low or absent in all three human breast carcinoma cell lines examined, but the defect in the IL‐1β signaling pathway may be different in ER positive versus ER negative carcinoma cells. © 2002 Wiley‐Liss, Inc.
Pathophysiologic role of myocardial apoptosis in post‐infarction left ventricular remodeling
Authors: Abbate Antonio , Biondi‐Zoccai Giuseppe GL , Baldi Alfonso
Published: October 2002

Left ventricular (LV) remodeling and heart failure (HF) complicate acute myocardial infarction (AMI) even weeks to months after the initial insult. Apoptosis may represent an important pathophysiologic mechanism causing progressive myocardiocyte loss and LV dilatation even late after AMI. This review will discuss the role of apoptosis according to findings in animal experimental data and observational studies in humans in order to assess clinical relevance, determinants, and mechanisms of myocardial apoptosis and potential therapeutic implications. More complete definition of the impact of myocardiocyte loss on prognosis and of the mechanisms involved may lead to improved understanding of cardiac remodeling and possibly improved patients' care. Mitochondrial damage and bcl‐2 to bax balance play a central role in ischemia‐dependent apoptosis while angiotensin II and β1‐adrenergic‐stimulation may be major causes of receptor‐mediated apoptosis. Benefits due to treatment with ACE‐inhibitors and β‐blockers appear to be in part due to reduced myocardial apoptosis. Moreover, infarct‐related artery patency late after AMI may be a major determinant of myocardial apoptosis and clinical benefits deriving from an open artery late post AMI (the “open artery hypothesis”) may be, at least in part, due to reduced myocardiocyte loss. © 2002 Wiley‐Liss, Inc.
Spontaneous dehydration mechanism of aromatic aldehyde reactions with hydroxyl and non‐hydroxyl amines
Authors: Travalon Silvana Azzolini , Brighente Inês Maria Costa , Yunes Rosendo Augusto
Published: October 2002

The plot of rate constants vs. pH for the dehydration step of the reaction between furfural and 5‐nitrofurfural with hydroxylamine, N‐methylhydroxylamine, and O‐methylhydroxylamine, shows two regions corresponding to the oxonium ion‐catalyzed and spontaneous dehydration. The oxonium ion‐catalyzed dehydration region of the reaction of furfural with the above mentioned hydroxylamines exhibits general acid catalysis with excellent Brønsted correlation (Brønsted coefficients: 0.76 (r = 0.986), 0.68 (r = 0.987), and 0.67 (r = 0.993) respectively). However, the rate constants of the spontaneous dehydration of these hydroxylamines, where water is considered the general acid catalyst, exhibit a large positive deviation from the Brønsted line. This fact was not observed in the reaction of non‐hydroxyl amines with different aromatic aldehydes by other authors, thus supporting that the spontaneous dehydration steps for these reactions proceed by intramolecular catalysis. The mechanism of intramolecular catalysis might be stepwise. First, a zwitterionic intermediate is formed. It can then evolve in the second step by loss of water, or follow a concerted pathway, with the transference of a proton through a five‐membered ring (general intramolecular acid catalysis). In the case of non‐hydroxyl amines, data suggested the possibility of a mechanism of intramolecular proton transfer through one or two water molecules, from the nitrogen of the amine to the leaving hydroxide ion. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 685–692, 2002
Output regulation of general discrete‐time linear systems with saturation nonlinearities
Authors: Hu Tingshu , Lin Zongli
Published: October 2002

This paper studies the classical problem of output regulation for linear discrete‐time systems subject to actuator saturation and extends the recent results on continuous‐time systems to discrete‐time systems. The asymptotically regulatable region, the set of all initial conditions of the plant and the exosystem for which the asymptotic output regulation is possible, is characterized in terms of the null controllable region of the anti‐stable subsystem of the plant. Feedback laws are constructed that achieve regulation on the asymptotically regulatable region. Copyright © 2002 John Wiley & Sons, Ltd.
Spectral and spatial anisotropy of the oxide growth onRu(0001)
Authors: Böttcher A. , Starke U. , Conrad H. , Blume R. , Niehus H. , Gregoratti L. , Kaulich B. , Barinov A. , Kiskinova M.
Published: October 2002

Scanning photoelectron spectromicroscopy has been used to study the onset and the initial stages of oxidation of Ru(0001) at three oxidation temperatures, 625, 675, and 775 K, and oxygen exposures of about 105 Langmuir. The lateral heterogeneity developed during oxide nucleation and growth and the local composition of the coexisting phases have been determined using as fingerprints the O 1s and Ru 3d spectra, thus combining chemical mapping with spectroscopy from selected features from the maps. The onset of oxide formation is characterized by the appearance of randomly distributed small islands (⩾0.5 μm) identified as germinal patches exhibiting some spectral features of bulk RuO2. The following anisotropic growth of the RuO2 phase and in particular the shape of the oxide islands shows a strong dependence on the oxidation temperature. The spectroscopic information obtained for the areas surrounding the oxide islands reveals an intermediate oxygen state characterized by distinct O 1s and Ru 3d features different from both the chemisorbed and the oxide form. It is assigned to an intermediate state acting as precursor of the oxide. The experimental data are discussed in the framework of the oxidation pathway and of core level fingerprints for the various oxygen–Ru phases suggested in recent theoretical models.
Dissociative electron attachment study to nitromethane
Authors: Sailer W. , Pelc A. , Matejcik S. , Illenberger E. , Scheier P. , Märk T. D.
Published: October 2002

Dissociative electron attachment (DEA) to CH3NO2 in the gas phase was studied in the electron energy range from zero up to 10 eV with an energy resolution of 140 meV. For the most intense negative fragments NO2−, O−, OH−, CN−, CNO− estimates for the absolute partial cross sections were obtained for the first time [σ(NO2)≈10−21 m2 at 0.62 eV, σ(O−)≈10−23 m2 at 5.4 eV, σ(OH−)≈10−24 m2 at 4 eV, σ(CN−)≈10−24 m2 at 1.7 eV, and σ(CNO−)≈10−25 m2 at 4 eV]. In the case of OH−, CN−, and CNO−, ion formation at very low electron energies (≈0 eV) has been observed in contrast to previous studies. The formation of OH− and CNO− at these low electron energies is explained in terms of DEA to vibrationally excited molecules. Analyzing measured partial cross sections, the standard enthalpy of formation of the CH3NO (nitroso-methane) and the CNO radical has been estimated, as ΔfHg∘(CH3NO)=129±30 kJ/mol and ΔfHg∘(CNO)=323±30 kJ/mol, respectively.
Nanosecond time-resolved multiprobe imaging of laser damage in transparent solids
Authors: Jiang H. , McNary J. , Tom H. W. K. , Yan M. , Radousky H. B. , Demos S. G.
Published: October 2002

We report the nanosecond time-scale and micron length-scale dynamics of elastic wave, plastic deformation, melt-front and crack propagation during laser-induced damage in the bulk of an optically transparent crystalline solid. Time-delayed probe pulses with wavelengths corresponding to RGB-color filters are used to obtain multiple images during a single damage event. This technique enables “real-time” dynamical studies of complex transient phenomena.