bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Stiffness Properties of Single-Ply Cord-Rubber Composites
Authors: Parhizgar S. , Weissman E. M. , Chen C. S.
Published: June 2006

Accurate determination of stiffness properties of cord-rubber composites is a key to successful finite element analysis of tires. The Halpin-Tsai and similar equations which are used to determine stiffness properties of cord-rubber single plies from the stiffness properties of cord and rubber do not provide adequate accuracy. Determination of these properties from strains directly measured by the Moire technique is more appropriate. In this paper the disadvantages of Halpin-Tsai and similar equations as well as the advantages of the Moire technique for cord-rubber composites are discussed. The stiffness properties obtained using the above different methods are compared. These stiffness properties are then used in the finite element analysis of a two-ply cord-rubber strip. The results of the finite element analyses are compared with experimental data.
Nonlinear Viscoelastic Finite Element Analysis of Adhesive Joints
Authors: Roy S. , Reddy J. N.
Published: June 2006

A good understanding of the process of adhesion from the mechanics viewpoint and the predictive capability for structural failures associated with adhesively bonded joints require a realistic modeling (both constitutive and kinematic) of the constituent materials. The present investigation deals with the development of an Updated Lagrangian formulation and the associated finite element analysis of adhesively bonded joints. The formulation accounts for the geometric nonlinearity of the adherends and the nonlinear viscoelastic behavior of the adhesive. Sample numerical problems are presented to show the stress and strain distributions in bonded joints.
Mechanical Losses in Rubbers Under Loading Conditions Typical of Tires in Service
Authors: Priss L. S. , Shumskaya A. G.
Published: June 2006

Mechanical losses in rubber compounds per strain cycle are shown to be considerably greater under pulse loading, which simulates tire usage, than under sinusoidal loading. A method is suggested for using data obtained by ordinary laboratory techniques to calculate losses that would occur in an arbitrary anharmonic mode. Some data are given to show how such mechanical losses depend on formulations and processing factors of the rubber. Methods are then discussed for obtaining proper laboratory data on dynamic properties for use in optimizing formulations of tire rubbers.
Fatigue Life of Aircraft Tires
Authors: Bobo S. N.
Published: June 2006

A study was conducted to determine if a safe upper service limit can be set for aircraft tires, based on an operation profile of the aircraft using the tires. The study consisted of three parts: development of a tire heating model, experimental confirmation, and determination of tire degradation as a function of time at temperature. Three operational profiles were identified: long, intermediate, and short haul; these stressed tires in different ways. The mathematical model, which calculated temperature as a function of time for various axial and lateral forces at different speeds, was developed and confirmed by experiment. It predicted the time at temperature of the hottest part of a tire that is exposed to the operating environment of the profiles. The impact of heating was found from a determination of ply adhesion as a function of time at temperature. The end of tire life was judged to occur when ply adhesion was degraded by 50%.
Tire Stress and Deformation from Composite Theory
Authors: Brewer H. K.
Published: June 2006

The pneumatic tire is treated as a laminated, anisotropic, toroidal shell of revolution possessing bending rigidity. The plies, which are constructed of elastic textile cords embedded in an elastic rubber matrix, are considered homogeneous and orthotropic on a macroscopic scale. The tire shell is considered to deform according to the classical Love hypothesis. The equilibrium, strain-displacement, and laminate constitutive equations governing the tire shell are reduced to a system of six first order, nonlinear, ordinary differential equations with variable coefficients which are solved numerically by a multi-segment forward integration technique. The geometrical nonlinearities due to finite displacements are accounted for by an incrementing process using transient coordinates. The theory is illustrated by a numerical calculation which shows good agreement with actual measurements.
Recent Studies of Tire Braking Performance
Authors: McCarty J. L. , Leland T. J. W.
Published: June 2006

The results from recent studies of some factors affecting tire braking and cornering performance are presented together with a discussion of the possible application of these results to the design of aircraft braking systems. The first part of the paper is concerned with steady-state braking, that is, results from tests conducted at a constant slip ratio or steering angle or both. The second part deals with cyclic braking tests, both single cycle, where brakes are applied at a constant rate until wheel lockup is achieved, and rapid cycling of the brakes under control of a currently operational antiskid system.
A Diagonally Braked Vehicle for the Investigation of Tire Traction
Authors: Yager T. J.
Published: June 2006

The development and application of a diagonally braked vehicle test technique has yielded insights into factors known to affect pneumatic tire traction such as certain tire parameters (including size, construction, and tread pattern) and pavement properties (including surface finish and the type and extent of contamination). This paper reviews the effects of tire and surface characteristics on available traction, discusses how the test results could be applied to estimate aircraft stopping performance under low traction conditions, and concludes with comments relative to possible future application of the diagonally braked vehicle.
Effect of Vehicle Suspension on Wet Tire Traction Testing
Authors: Boyd P. L.
Published: June 2006

A pair of “intermediate” size sedans of each of the three suspension types was put through constant radius cornering and straight stopping maneuvers on wet pavements. All cars used the same original equipment tire design. Speed and acceleration were measured. All three suspension types gave equivalent cornering performance and only slight differences in stopping deceleration. But the vehicles with rear suspensions consisting of coil springs and control arms were more suitable for sudden lockup stopping because they were less prone to a severe transient condition known as “wheel hop”.
Research on Wet Tire Traction
Authors: Neill A. H. , Boyd P. L.
Published: June 2006

This paper describes experiments and methodology employed in an attempt to develop a system for the grading of wet tire traction. Data from instrumented vehicle experiments and the University of Michigan Highway Safety Research Institute mobile tire tester are used to support the conclusions. The vehicle tests include J-curve cornering and diagonal, locked-wheel braking. The maneuvers are used to generate information on tire tractive properties and their dependence on tread depth, rim size, suspension, and surface conditions. Three tire force measures obtained with the mobile tire tester, the peak longitudinal, peak free-rolling lateral, and locked-wheel longitudinal coefficients of friction, are presented for a group of 90 percent of the original equipment tire sizes in use on American cars and are rank correlated with vehicle results. The results indicate the feasibility of defining minimum wet traction levels for various tire-road interface properties.
Application of Holography to the Study of Tire Vibration
Authors: Potts G. R.
Published: June 2006

Tire vibrations were studied by applying an oscillatory load to bias, belted bias, and radial ply tires in the radial, lateral, and circumferential directions. Resonant frequencies were noted in each type of tire and the corresponding mode shapes observed with both real time and time average holography. The importance of tire vibrations in affecting vehicle ride is noted and the variables affecting these vibrations discussed.
Effects of Rotation Patterns on Tread Life Evaluation
Authors: Brenner F. C. , Kondo A.
Published: June 2006

The effects of making tread life evaluations using different patterns of rotation are reported. It is shown that the estimated average tread life for a tire was not statistically different in experiments with four tires in fixed wheel position, on fixed axles, or fully rotated to all wheel positions. The fully rotated procedure produced the same average for a pair of tires or for four tires; the variability of the data was significantly smaller than in the other rotation patterns.
Ranking Tires for Heavy Truck Steering Feel Performance Using a Simulation Model
Authors: Haas S. L.
Published: June 2006

The effects of seven different tire sets on heavy truck steering feel characteristics were demonstrated from objective testing. Also, the steering behavior and vehicle dynamics were modeled in order to determine how well the resulting simulations could rank the steering performance of the tire sets relative to the objective results.

The objective testing was performed using a 6×4 tractor with a two-axle flatbed semi-trailer. Measured data included steering wheel torque, steering wheel angle, and lateral acceleration behavior resulting from on-center-type steering tests. In addition, the hydraulic pressure from the power steering system was also measured. The tests consisted of multiple cycles at 0.2 Hz and ±0.2 g. Steering-related performance metrics were selected and calculated based on the interaction between measured parameters.

The same test procedure was also applied using an analytical model of a steering system. The input was steering wheel torque, and outputs included the road wheel angles at the steer axle, which were then fed into a commercial vehicle dynamics model providing the vehicle dynamics behavior along with feedback required for the steering model (e.g., king pin moments). Tire loads and slip angles were also provided by the vehicle dynamics model and used as input to a tire model predicting tire force and moment behavior. The related metrics were subsequently computed and compared to the measured results.

Effects of the different tire sets on steering characteristics were seen from both the objective and simulation tests. Seven performance metrics were applied in a ranking comparison between measured and modeled results. Correlation of the modeled to measured metrics ranged from R2 values of 0.40 to 0.99 for the seven metrics considered.
Rim Slip and Bead Fitment of Tires: Analysis and Design
Authors: Lee C.
Published: June 2006

A tire slips circumferentially on the rim when subjected to a driving or braking torque greater than the maximum tire-rim frictional torque. The balance of the tire-rim assembly achieved with weight attachment at certain circumferential locations in tire mounting is then lost, and vibration or adverse effects on handling may result when the tire is rolled. Bead fitment refers to the fit between a tire and its rim, and in particular, to whether a gap exists between the two.

Rim slip resistance, or the maximum tire-rim frictional torque, is the integral of the product of contact pressure, friction coefficient, and the distance to the wheel center over the entire tire-rim interface. Analytical solutions and finite element analyses were used to study the dependence of the contact pressure distribution on tire design and operating attributes such as mold ring profile, bead bundle construction and diameter, and inflation pressure, etc. The tire-rim contact pressure distribution consists of two parts. The pressure on the ledge and the flange, respectively, comes primarily from tire-rim interference and inflation. Relative contributions of the two to the total rim slip resistance vary with tire types, depending on the magnitudes of ledge interference and inflation pressure. Based on the analyses, general guidelines are established for bead design modification to improve rim slip resistance and mountability, and to reduce the sensitivity to manufacturing variability. An iterative design and analysis procedure is also developed to improve bead fitment.
A Study of the In-Plane Force Transmission of Tires
Authors: Dorfi H. R.
Published: June 2006

A better understanding of the tire force transmission mechanisms from footprint to spindle due to cleat impact and other road disturbances is important to improve the ride performance of the tire/vehicle system. In this study, the in-plane force transmission of tires rolling over cleats is studied using various approaches: analytical, numerical and experimental. The tire force response at the spindle is compared and several important observations are made. Results reported in the literature are critically reviewed as well.
Analysis of Tire Rolling Contact Response by REF Model
Authors: Wei Y. T. , Nasdala L. , Rothert H.
Published: June 2006

Analysis for tire dynamic response rolling over an obstacle is important to study automobile NVH (Noise-Vibration-Harshness), determine vehicle fatigue load, investigate combined longitudinal and sideslip properties, and develop ABS system on uneven roads. Based on the model of Ring on the Elastic and Viscoelastic Foundation (REF) and its analytical solution previously developed, the rolling contact problem between tire/flat and tire/cleat is dealt with in this paper. The static contact problem is treated as the first step to show the effectiveness and accuracy of the model. Then, the time domain simulation of tire rolling contact on uneven roads is conducted. Meirovitch modal analysis method and first-order matrix perturbation theory are applied to obtain the general forced response of damping REF vibration. An effective numerical quadrature method is developed to obtain the time-varying modal coordinates of the system under various loading conditions. Numerical examples of a tire rolling over a cleat are given to verify the developed method. It is found that both damping and velocity have strong effects on tire response over a cleat and the frequency of dynamic load is mainly controlled by the first tire mode.
Pattern Recognition for Classification and Matching of Car Tires
Authors: Colbry D. , Cherba D. , Luchini J.
Published: June 2006

Commercial databases containing images of tire tread patterns are currently used by product designers, forensic specialists and product application personnel to identify whether a given tread pattern matches an existing tire. Currently, this pattern matching process is almost entirely manual, requiring visual searches of extensive libraries of tire tread patterns. Our work explores a first step toward automating this pattern matching process by building on feature analysis techniques from computer vision and image processing to develop a new method for extracting and classifying features from tire tread patterns and automatically locating candidate matches from a database of existing tread pattern images.

Our method begins with a selection of tire tread images obtained from multiple sources (including manufacturers' literature, Web site images, and Tire Guides, Inc.), which are preprocessed and normalized using Two-Dimensional Fast Fourier Transforms (2D-FFT). The results of this preprocessing are feature-rich images that are further analyzed using feature extraction algorithms drawn from research in computer vision. A new, feature extraction algorithm is developed based on the geometry of the 2D-FFT images of the tire.

The resulting FFT-based analysis allows independent classification of the tire images along two dimensions, specifically by separating “rib” and “lug” features of the tread pattern. Dimensionality of (0,0) indicates a smooth treaded tire with no pattern; dimensionality of (1,0) and (0,1) are purely rib and lug tires; and dimensionality of (1,1) is an all-season pattern. This analysis technique allows a candidate tire to be classified according to the features of its tread pattern, and other tires with similar features and tread pattern classifications can be automatically retrieved from the database.
A Finite Element Model for Oven Aged Tires
Authors: Ellwood K. R. J. , Baldwin J. , Bauer D. R.
Published: June 2006

A finite element kinetic model has been developed to interpret issues related to accelerated aging of tires. The model is based on the Basic Autoxidation Scheme and incorporates mass transport limitations related to diffusion of oxygen into the layered elastomer system. The effect of aging on transport properties, such as diffusivity, due to changes in crosslink density is also considered in the model. The extent of oxidation is calculated at different locations within the tire as a function of time, temperature, and inflation media. The extent of oxidation predicted by the model is compared to experimentally derived data such as oxygen content, crosslink density, elongation-to-break, and modulus variation.
Modeling of the Dynamic Mechanical Response of Elastomers
Authors: Bergström J. S.
Published: June 2006

The mechanical behavior of elastomers is characterized by rate- and temperature-dependence, and the stress-strain response is known to be strongly non-linear. These experimental features are well recognized and important, and have been extensively studied for more than 50 years. The understanding of the micromechanisms controlling the macroscopic mechanical behavior is much more recent, and advanced modeling tools allowing for accurate predictions of arbitrary deformation histories have only started to become available during the last few years. This paper outlines the current state of the art in finite element modeling of elastomers, and exemplifies the predictive capabilities of modern constitutive theories for filled elastomers.
Self‐organisation and material constructions
Authors: Weinstock Michael
Published: June 2006

Cellular biological materials have intricate interior structures, self‐organised in hierarchies to produce modularity, redundancy and differentiation. As Michael Weinstock explains, the foam geometries of cellular materials offer open and ductile structural systems that are strong and permeable, making them an attractive paradigm for developments in material science and for new structural systems in architecture and engineering. Copyright © 2006 John Wiley & Sons, Ltd.
Plus, plus ça change at the museum of modern art in New York
Authors: Merkel Jayne
Published: June 2006

The selection of Yoshio Taniguchi, in 1997, to design the Museum of Modern Art's enormous expansion was generally considered conservative, if not outright old‐fashioned. When the museum reopened in November 2004, most critics described the new scheme as ‘contextual’ or ‘subtle’, and noted that the architect had said he had tried ‘to make the architecture go away’. Now that enough time has passed to blur expectations, Jayne Merkel looks at MoMA as it is today. She contends that the choice was progressive in exactly the way the museum has been all along, and that the architecture is very much there. Copyright © 2006 John Wiley & Sons, Ltd.
Optically Transparent, Ultrathin Pt Films as Versatile Metal Substrates for Molecular Optoelectronics
Authors: Conoci S. , Petralia S. , Samorì P. , Raymo F. M. , Di Bella S. , Sortino S.
Published: June 2006

This contribution reports a simple, straightforward method (cool sputtering) of fabricating robust, homogeneous, conductive, and optically transparent ultrathin Pt films. Their morphological, structural, mechanical, electrical, and optical properties are reported. The morphology and structure of these Pt films are investigated by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and X‐ray diffraction. The ultrathin Pt films, approximately 20 nm thick, are characterized by a homogenous, polycrystalline structure, with a tendency to adopt a (111) texture upon the thermal treatment. Moreover, thermal treatment (annealing or flaming) of the as‐prepared films also substantially improves their chemical and mechanical robustness. F films behave as bulk Pt in terms of electrical resistivity and suitability as working electrodes in cyclic voltammetry experiments. Overall, the unique combination of these excellent features: homogeneity, robustness, and conductivity, in addition to the high optical transparency in the 300–800 nm range of the electromagnetic spectrum, make ultrathin Pt films appropriate for a variety of applications in the field of molecular optoelectronics. The formation of functional molecular self‐assembled monolayers (SAMs) on these transparent, conductive films allows their optical monitoring using transmission optical spectroscopy, as well as the probing of their electrical properties. The potential of such Pt films as suitable metal substrates in opto‐ and nanoelectronics is proven by representative applications, including switching of prototypical photochromic and electrochromic species in SAMs and molecule–metal junctions.
An LMA‐Effortsimulator with dynamics parameters for motion capture animation
Authors: Chao Shih‐Pin , Yang Shi‐Nine , Lin Tsang‐Gang
Published: June 2006

This paper presents a dynamics‐basedEffortsimulator so that a given motion can be modified according to specifiedEffortqualities. The basic idea of our approach is to establish relations betweenEffortfactors such as Space, Weight, Time, and Flow, and their corresponding dynamics parameters such as force, stiffness, inertia, damping, gravity, and etc in the simulator. Then, a motion with specifiedEffortquality can be realized by mapping it to appropriate dynamics parameters of the simulator. The proposed simulator has two merits: it is motion capture‐driven, therefore it is able to synthesize motion details and easily to be incorporated into popular motion capture applications. Besides, it is dynamics based and therefore it provides high‐level control intuition of motion dynamics in specifyingEffortqualities. To demonstrate the effectiveness of the proposed simulator, several experimental examples are presented and their results are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Bringing haptics and physical simulation together: haptic travel through physical worlds
Authors: Jorissen Pieter , De Boeck Joan , Lamotte Wim
Published: June 2006

This paper describes our efforts in bringing haptics closer to current dynamic virtual environments (VE). These interactive 3D worlds make more and more use of physical simulations in order to increase realism. As a first step in closing the gap, we propose haptic travel that allows users to feel how their virtual representation navigates through the simulated world. In this work, we show how we coupled stable haptic rendering to physical simulation in order to achieve this. By generating a force feedback field, based on the user's input in combination with collision information provided by a rigid body simulator, we managed to provide the user with useful information on what is happening to its virtual representation. A humanoid animated character, which represents the user, is coupled to the rigid body object that represents the user in physical space. This character is animated according to the travel motions that the physical object makes, depending on user input from the haptic device. Our approach is suitable for a whole set of applications and input devices and can reduce the number of devices necessary to interact in VEs. Copyright © 2006 John Wiley & Sons, Ltd.
Understanding visuo‐motor primitives for motion synthesis and analysis
Authors: Guerra‐Filho Gutemberg , Aloimonos Yiannis
Published: June 2006

The problem addressed in this paper concerns the representation of human movement in terms of atomic visuo‐motor primitives considering both generation and perception of movement. We introduce the concept of kinetology, the phonology of human movement, and five principles on which such a system should be based: compactness, view‐invariance, reproducibility, selectivity, and reconstructivity. We propose visuo‐motor primitives and demonstrate their kinetological properties. Further evaluation is accomplished with experiments on compression and decompression. Our long‐term goal is to demonstrate that action has a space characterized by a visuo‐motor language. Copyright © 2006 John Wiley & Sons, Ltd.
A Wizard‐of‐Oz platform for embodied conversational agents
Authors: Brown Edward , Barrett Neil
Published: June 2006

A low‐cost prototyping environment for experimenting with embodied conversational agents is discussed. The platform allows modeling and experimenting with different agent constructs and protocols prior to significant investment in the construction of the agent environment. Problems in the design of such a platform include the substantial number of agent controls needed and the flexibility required to represent the constructs of different theories, protocols and target environments as they are introduced and developed. These problems are addressed by augmenting a movie clip manager with a general drawing palette as a design tool. The result is a prototyping environment which simulates multiple agents on a desktop while allowing arbitrary notational conventions. The current version does not render multiple agents in a shared virtual environment, but the protocol‐based architecture is amenable to such extensions. In the meantime, valuable results regarding the social character of multiple agent interaction can be explored with the existing tool. Copyright © 2006 John Wiley & Sons, Ltd.
Automatic muscle generation for character skin deformation
Authors: Yang Xiaosong , Zhang Jian J.
Published: June 2006

As skin shape depends on the underlying anatomical structure, the anatomy‐based techniques usually afford greater realism than the traditional skeleton‐driven approach. On the downside, however, it is against the current animation workflow, as the animator has to model many individual muscles before the final skin layer arrives, resulting in an unintuitive modelling process. In this paper, we present a new anatomy‐based technique that allows the animator to start from an already modelled character. Muscles having visible influence on the skin shape at the rest pose are extracted automatically by studying the surface geometry of the skin. The extracted muscles are then used to deform the skin in areas where there exist complex deformations. The remaining skin areas, unaffected or hardly affected by the muscles, are handled by the skeleton‐driven technique, allowing both techniques to play their strengths. In order for the extracted muscles to produce realistic local skin deformation during animation, muscle bulging and special movements are both represented. Whereas the former ensues volume preservation, the latter allows a muscle not only to deform along a straight path, but also to slide and bend around joints and bones, resulting in the production of sophisticated muscle movements and deformations. Copyright © 2006 John Wiley & Sons, Ltd.
Simulation of miscible binary mixtures based on lattice Boltzmann method
Authors: Zhu Hongbin , Liu Xuehui , Liu Youquan , Wu Enhua
Published: June 2006

Miscible fluid mixtures, like pouring honey into water, Coca Cola into strong wine, are common phenomena in our daily life. While two miscible fluids are mixed together, their appearances in terms of colors and shapes will change due to their mixing interaction. The interaction between the mixture components could be regarded as a combination of the diffusing process and demixing process. If the former dominates the interaction, it is miscible; otherwise, it is immiscible. The complex microscopic interplay between the mixture components makes the simulation highly challenging. So far, there have been some dedicated research in computer graphics dealing with immiscible mixtures, but few works have been done focusing on miscible mixtures. In this paper, for the first time, we introduce a two‐fluid lattice Boltzmann method (LBM), called TFLBM, applied to miscible binary mixtures. Different from other similar methods, the viscous and diffusing properties of the fluid in our work are considered separately, so that the physical insight is exposed more clearly and rationally. In addition, the operation of LBM is mostly a linear local computation, and graphics processing unit (GPU) has been utilized to achieve real‐time simulation. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis of 3D faces using region‐based morphing under intuitive control
Authors: Zhang Yu , Badler Norman I.
Published: June 2006

This paper presents a new region‐based method for automatically synthesizing varied, natural looking 3D human face models by morphing local facial features according to intuitive control parameters. We automatically compute a one‐to‐one vertex correspondence among the unregistered face scans in a large database by deforming a generic mesh to fit the specific person's face geometry in a global‐to‐local fashion. With the obtained correspondence, we transform the generated data sets of feature shapes into vector space representations. We parameterize the example models using the face anthropometric measurements that reflect the facial physical structure, and predefine the interpolation functions for the parameterized example models based on radial basis functions. At runtime, the interpolation functions are evaluated to efficiently generate the appropriate feature shape by taking the anthropometric parameters as input. We use a shape blending approach for generating a seamlessly deformed mesh around the feature region boundary. The correspondence among all example textures is established by parameterizing the 3D generic mesh over a 2D image domain. The new feature texture with desired attributes is synthesized by interpolating the example textures. Our 3D face synthesis method has several advantages: (1) it regulates the naturalness of synthesized faces, maintaining the quality existing in the real face examples; (2) the region‐based morphing and comprehensive face shape and texture control parameters allow more diverse faces to be generated readily; and (3) the automatic runtime face synthesis is efficient in time complexity and performs fast. Copyright © 2006 John Wiley & Sons, Ltd.
Using prefetching to improve walkthrough latency
Authors: Hung Shao‐Shin , Liu Damon Shing‐Min
Published: June 2006

Object correlations are common semantic patterns in walkthrough (WT) systems. They can be exploited for improving the effectiveness of storage caching, prefecthing, data layout, and minimization of query‐response times. Previous approaches for reducing I/O access time are seldom investigated. On the other side, data mining techniques extract implicit, previously unknown and potentially useful information from the databases. However, those methods are presented for typical data mining datasets and not suitable for our WT system datasets. This paper proposes a class of novel and efficient pattern‐growth method for mining various frequent sequential traversal patterns in the WT. Our pattern‐growth method adopts a divide‐and‐conquer approach to decompose both the mining tasks and the databases. The frequent sequential traversal patterns are used to predict the user navigation behavior and help to reduce disk access time with proper placement patterns into disk blocks. We also define the terminologies such as paths, views, and objects used in the model. We have done extensive experiments to demonstrate how these proposed techniques not only significantly cut down disk access time, but also enhance the accuracy of data prefetching. Copyright © 2006 John Wiley & Sons, Ltd.
Formation of Disperse Nanoparticles at the Oil/Water Interface in Normal Microemulsions
Authors: Ge Jian‐Ping , Chen Wei , Liu Li‐Ping , Li Ya‐Dong
Published: June 2006

An artificial oil/water interface was created in normal microemulsions. Various well‐dispersed inorganic nanoparticles were successfully fabricated at this micelle interface, and a “hot liquid annealing” process was used to crystallize the products. Owing to the large solubility of the source materials in the water phase, the colloidal nanoparticles can easily be prepared on a large scale. Compared with traditional reverse‐microemulsion methods, the method reported here yields larger amounts of colloidal particles but with the same quality.
Minimization of Electrode Adsorption Effects: The Cadmium–Humic Acid System Studied by Phase Sensitive Alternating Current Polarography
Authors: Garrigosa Anna M. , Ariño Cristina , Díaz‐Cruz José Manuel , Esteban Miquel
Published: June 2006

The use of phase‐sensitive Alternating Current Polarography (ACP) is investigated for the minimization of adsorption effects in metal‐ligand systems with induced metal adsorption onto the electrode. When ACP is applied to obtain information on metal complexation in bulk, some problems arise from the faradaic contribution of adsorbed species. This effect can be corrected by using the capacitive current measured in the potential region of the faradaic peak. Using this correction, ACP produces similar results to those from Reverse Pulse Polarography (RPP), a technique that minimizes electrode adsorption effects on the measured currents. The method proposed is applied to the study of the Cd–humic acid system that has been investigated by ACP, RPP and Differential Pulse Polarography (DPP).
N‐terminal deletion affects catalytic activity of saporin toxin
Authors: Bonini Francesca , Traini Roberta , Comper Fabrizio , Fracasso Giulio , Tomazzolli Rossella , Serra Mauro Dalla , Colombatti Marco
Published: June 2006

Single‐chain ribosome inactivating proteins (RIPs) are cytotoxic components of macromolecular pharmaceutics for immunotherapy of cancer and other human diseases. Saporin belongs to a family of single‐chain RIPs sharing sequence and structure homology. In a preliminary attempt to define an active saporin polypeptide of minimum size we have generated proteins with deletions at the N‐terminus and at the C‐terminus. An N‐terminal (sapΔ1–20) deletion mutant of saporin displayed defective catalytic activity, drastically reduced cytotoxicity but increased ability to interact with liposomes inducing their permeabilization at low pH. A C‐terminal (sapΔ239–253) deletion mutant showed instead a moderate reduction in cytotoxic activity. A substantial alteration of secondary structure was evidenced by Fourier transformed infrared spectroscopy (FTIR) in the sapΔ1–20 mutant. It can be hypothesized that the defective functions of sapΔ1–20 are due to alterations of its spatial configuration. J. Cell. Biochem. 98: 1130–1139, 2006. © 2006 Wiley‐Liss, Inc.
Regulation of angiogenesis and tumor growth by p110 Alpha and AKT1 via VEGF expression
Authors: Xia Chang , Meng Qiao , Cao Zongxian , Shi Xianglin , Jiang Bing‐Hua
Published: June 2006

Recent studies demonstrate that PI3K activation and PTEN mutation are frequently found in many human cancer cells and tissues. However, the mechanism of PI3K signaling in human cancer tumorigenesis remains to be elucidated. In this study we specifically downregulated p110α expression in ovarian cancer cells using siRNA interference. We found that p110α downregulation greatly decreased ovarian tumor growth and angiogenesis, and that p110α siRNA inhibited VEGF expression through decreasing hypoxia‐inducible factor 1α expression in both ovarian cancer cells and tumor tissues. To determine the downstream targets of PI3K in regulating tumor growth and angiogenesis, we find that AKT1 is a major downstream mediator for regulating tumor growth, angiogenesis, and VEGF expression. These data show that p110α and AKT1 play an important role in tumor growth by inducing angiogenesis and by increasing HIF‐1α and VEGF expression. This work provides a better understanding of the molecular mechanism of human cancer induced by the activation of PI3K signaling. J. Cell. Physiol. 209: 56–66, 2006. © 2006 Wiley‐Liss, Inc.
Identification of oleuropein oligomers in olive pulp and pomace
Authors: Cardoso Susana M , Guyot Sylvain , Marnet Nathalie , Lopes‐da‐Silva José A , Silva Artur MS , Renard Catherine MGC , Coimbra Manuel A
Published: June 2006

Analysis of a purified fraction from acetone extracts of olive pulp and pomace by electrospray ionisation tandem mass spectrometry (ESI‐MSn) showed the presence of oleuropein oligomers, whose occurrence has not been reported previously in the literature. The main ionic species (m/z 1613) in the ESI‐MS spectrum was an oleuropein trimer containing three linkages through the hydroxytyrosol backbone. In both samples, oleuropein dimers (m/z 1075), trimers comprising two hydroxytyrosol linkages (m/z 1615), tetramers (m/z 2153) and pentamers (m/z 2691) were also detected by MS. The occurrence of oleuropein oligomers was also observed by nuclear magnetic resonance (NMR). 13C, 13C distortionless enhancement by polarisation transfer DEPT 90, 13C DEPT 135, gHSQC (heteronuclear single quantum coherence) and gHMBC (heteronuclear multiple bond coherence) spectra showed all carbon and proton resonances of oleuropein with the exception of the low‐mobility and asymmetric signals of the aromatic rings. Since mature olives were used in this study, it is possible that the disappearance of oleuropein that has been described to occur with the olive fruit maturation, could be associated with the formation of phenolic oligomers together with lower‐molecular‐weight compounds resulting from its degradation. Copyright © 2006 Society of Chemical Industry
Enzymatic Erosion of Bioartificial Membranes to Control Drug Delivery
Authors: Coluccio Maria Laura , Ciardelli Gianluca , Bertoni Franca , Silvestri Davide , Cristallini Caterina , Giusti Paolo , Barbani Niccoletta
Published: June 2006

Summary: The preparation of an enzymatic controlled drug release system from blends of PVA/starch/αA, in the form of films, is described. It was shown that αA hydrolyses the starch within these films, resulting in a time‐dependent change of the porosity in the matrix. Films were characterized by calorimetric analysis to study the interactions between the enzyme and the polymeric constituents at the molecular level. The presence of αA, in fact, influenced the PVA cristallization in the blends. Release tests and permeability experiments were carried out to evaluate the transport properties of the films. An increase in porosity and permeability was observed by increasing αA content (16–28 wt.‐%). Films loaded with theophylline and caffeine were also prepared to analyze drug release properties of the matrix. Drug release kinetics were coherent with the measured changes in porosity: at higher αA concentrations the amount of released drug increased under the influence of diffusion and erosion processes. The results obtained are promising for the realization of drug delivery devices for a rapid release or for the release of poorly soluble drugs which usually remain entrapped in the matrix.

SEM images of a PVA/starch/αA film before (A) and after (B) the erosion.

magnified image

SEM images of a PVA/starch/αA film before (A) and after (B) the erosion.
Using multimethods ethnography to promote quality service and understand interactions among organizations
Authors: Schneider Jo Anne
Published: June 2006

Multimethods ethnography combines qualitative techniques with analysis of statistical data and sometimes mapping techniques. Ethnography provides a comprehensive picture of process in an agency or other setting by examining the dynamics between individuals and institutions to understand how systems work. Ethnography is particularly good at evaluating complex problems involving multiple stakeholders as well as understanding agency processes. I use examples from the Neighborhood Settlement House Evaluation Project and Kenosha Social Capital Study to describe the ethnographic method and its potential uses for nonprofit managers. I begin with an outline of methodological techniques, including problem definition, sample design, various data collection techniques, and analysis. Next I discuss ethnography's approach to the common research concerns of generalizability and replication. In concluding, I discuss ways that this method can be useful to nonprofit managers. Quality work is compared with less complete research techniques throughout each section.
On the improvement of the open circuit voltage of plastic solar cells by the presence of a thin aluminium oxide layer at the interface organic/aluminium
Authors: Karst N. , Bernède J. C.
Published: June 2006

The open circuit voltage, V oc, of organic solar cells based on single donor/acceptor (D/A) interface has been studied as a function of the air exposure. It is shown that V oc increases when the Al upper electrode is air exposed, that is to say when a thin aluminium oxide layer is present at the interface organic donor/aluminium. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of four mass analyzers for determining carbosulfan and its metabolites in citrus by liquid chromatography/mass spectrometry
Authors: Soler Carla , Hamilton Brett , Furey Ambrose , James Kevin J. , Mañes Jordi , Picó Yolanda
Published: June 2006

Four liquid chromatography/mass spectrometry (LC/MS) systems, equipped with single quadrupole, triple quadrupole (QqQ), quadrupole ion trap (QIT) and quadrupole time‐of‐flight (QqTOF) mass analyzers, were evaluated for the analysis of carbosulfan and its main transformation products. The comparison of quantitative aspects (sensitivity, precision and accuracy) was emphasized. Results showed that the triple quadrupole instrument reaches at least 20‐fold higher sensitivity (LOD from 0.04 to 0.4 µg kg−1) compared to the single quadrupole (4–70 µg kg−1), the QIT (4–25 µg kg−1) and the QqTOF (4–23 µg kg−1) instruments. Recoveries were over 70% for all the analytes, except dibutylamine and 7‐phenolcarbofuran. Repeatabilities (within‐day) were slightly better by the single quadrupole (5–10%) and the QqQ (5–9%) than by the QIT (12–16%) and the QqTOF (9–16%). Both the QqTOF and QIT offer a linear dynamic range of two orders of magnitude whereas the single quadrupole and QqQ of, at least, three orders of magnitude. The method was applied to analyze carbosulfan field‐treated orange samples, in which carbosulfan, carbofuran, 3‐hydroxycarbofuran, and dibutylamine were found. As an example, the mean carbosulfan concentration was 20 ± 0.6 µg kg−1 measured by the QqQ, 22 ± 1.2 µg kg−1 by the single quadrupole, 25 ± 2.8 µg kg−1 by the QIT, and 20 ± 1.8 µg kg−1 by the QqTOF. Although the QqQ is more sensitive and precise, the mean values obtained by the four instruments are acceptable and comparable. The potential of each technique for the verification of the identity of residues detected in oranges is discussed using the concept of identification points. Copyright © 2006 John Wiley & Sons, Ltd.
Determination of refractory elements in atmospheric particulates using slurry sampling electrothermal vaporization inductively coupled plasma optical emission spectrometry and inductively coupled plasma mass spectrometry with polyvinylidene fluoride as chemical modifier
Authors: Zhang Yuefei , Jiang Zucheng , Hu Bin
Published: June 2006

Electrothermal vaporization (ETV) inductively coupled plasma optical emission spectrometry (ICP‐OES) and inductively coupled plasma mass spectrometry (ICP‐MS) with polyvinylidene fluoride (PVDF) as chemical modifier are critically compared for the determination of refractory elements in coal fly ash and airborne particulates. The atmospheric particulates that collected on a PVDF filter were introduced into the graphite furnace in the form of a slurry by dissolving the filter in dimethylformamide, and the dissolved filter PVDF, along with additional added PVDF powder, was used as a chemical modifier for subsequent ETV‐ICP‐OES and ETV‐ICP‐MS determination. The vaporization behaviors of analytes (Ti, Zr, V, Mo, Cr, La) in ETV‐ICP‐OES/MS were studied in detail, and the optimal ETV operating parameters were obtained. Under the optimized operating conditions, the detection limits of target elements were 0.08–2.7 ng m−3 for ETV‐ICP‐OES and 0.5–50 pg m−3 for ETV‐ICP‐MS, respectively, with analytical precisions of 3.5–7.3% for ETV‐ICP‐OES and 3.9–9.6% for ETV‐ICP‐MS, respectively. The tolerable amounts of matrix elements for ETV‐ICP‐OES are higher than for ETV‐ICP‐MS. Both ETV‐ICP‐OES and ETV‐ICP‐MS were used to directly determine the trace refractory elements in coal fly ash and airborne particulates and the analytical results are comparable. Copyright © 2006 John Wiley & Sons, Ltd.
Gas chromatography/mass spectrometric analysis of N,N‐dialkylaminoethyl‐2‐chlorides and trimethylsilyl derivatives of N,N‐dialkylaminoethan‐2‐ols for verification of the Chemical Weapons Convention
Authors: Gupta Arvinda K. , Pardasani Deepak , Kanaujia Pankaj K. , Tak Vijay , Dubey Devendra K.
Published: June 2006

Gas chromatography/electron ionization mass spectrometry (GC/EI‐MS) of N,N‐dialkylaminoethyl‐2‐chlorides (DAAECls) and trimethylsilyl (TMS) derivatives of N,N‐dialkylaminoethan‐2‐ols (DAAEAs) has been carried out. GC/EI‐MS data of these compounds are of importance for verification of the Chemical Weapons Convention (CWC). Based on these EI mass spectra, generalized fragmentation routes are proposed that rationalize most of the characteristic ions. Copyright © 2006 John Wiley & Sons, Ltd.
Cognitive assessment of musculoskeletal pain with a newly validated Greek version of the Fear‐Avoidance Beliefs Questionnaire (FABQ)
Authors: Georgoudis George , Papathanasiou George , Spiropoulos Panagiotis , Katsoulakis Kostantinos
Published: June 2006

Fear of pain and avoidance are psychological factors of primary importance when assessing chronic musculoskeletal pain, which are often measured with the Fear‐Avoidance Beliefs Questionnaire (FABQ). Both two‐ and three‐subscale versions have been described. The aims of this study were: to assess the cognitive traits of musculoskeletal pain patients using a newly validated Greek version of the FABQ, and to further examine the construct validity and responsiveness of the measure. Factor analysis yielded three factors that accounted for 65% of the total variance. Physical activity explained 12.3% of the variance and was identical to the original version, unlike the work subscale which split into two: the FABQ work1 related to “work as cause” (15.2% of the variance) and the FABQ work2 related to “work as prognosis” (37.5% of the variance). Internal consistency was good (0.72–0.90). Test–retest reliability was satisfactory and close to the original version both for individual items and the subscales. Responsiveness of the 3‐factor model was satisfactorily assessed as the ability to detect: (A) change in general – (paired t test, effect size); (B) clinically important change (paired t test, standardised effect size), and (C) real change in the concept being measured (ROC analysis). Construct validity of the FABQ was shown through the interaction with anxiety and depression, pain control and responsibility, psychological distress and pain intensity, and criterion‐related validity through the association with another fear‐avoidance measure (TSK). New aspects of responsiveness and construct validity were demonstrated for the FABQ, using a three‐subscale validated Greek version.
Legal and ethical issues in telemedicine and robotics
Authors: Dickens B.M. , Cook R.J.
Published: June 2006

Modern medical concerns with telemedicine and robotics practiced across national or other jurisdictional boundaries engage the historical, complex area of law called conflict of laws. An initial concern is whether a practitioner licensed only in jurisdiction A who treats a patient in jurisdiction B violates B's laws. Further concerns are whether a practitioner in A who violates a contract or treats a patient in B negligently incurs liability in B, A, or both, and, if treatment lawful in A is unlawful in B, whether the practitioner commits a crime. Judicial procedures are set by courts in which proceedings are initiated, but courts may decline jurisdiction due to inconvenience to parties. If courts accept jurisdiction, they may apply their own substantive legal rules, but may find that the rules of a conflicting jurisdiction should apply. Cross‐border care should not change usual medical ethics, for instance on confidentiality, but may mitigate or aggravate migration of specialists.