bluuebunny/crossref_metadata_2025_split huggingface dataset:
An energy‐consistent material‐point method for dynamic finite deformation plasticity
Authors: Love E. , Sulsky D. L. 
Published: October 2005

AbstractEnergy consistency for the material‐point method (MPM) is examined for thermodynamically consistent hyperelastic‐plastic materials. It is shown that MPM can be formulated with implicit, three‐ field variational, finite element algorithms which dissipate energy and conserve momentum for that class of material models. With a consistent mass matrix the resulting overall numerical method inherits the energy‐dissipative and momentum‐conserving properties of the mesh solution. Thus, the proposed MPM algorithm satisfies by construction a time‐discrete form of the second law of thermo‐ dynamics. Properties of the method are illustrated in numerical examples. Copyright © 2005 John Wiley & Sons, Ltd.
Use of higher‐order shape functions in the scaled boundary finite element method
Authors: Vu Thu Hang , Deeks Andrew J. 
Published: October 2005

AbstractThe scaled boundary finite element method is a novel semi‐analytical technique, whose versatility, accuracy and efficiency are not only equal to, but potentially better than the finite element method and the boundary element method for certain problems. This paper investigates the possibility of using higher‐order polynomial functions for the shape functions. Two techniques for generating the higher‐order shape functions are investigated. In the first, the spectral element approach is used with Lagrange interpolation functions. In the second, hierarchical polynomial shape functions are employed to add new degrees of freedom into the domain without changing the existing ones, as in the p‐version of the finite element method. To check the accuracy of the proposed procedures, a plane strain problem for which an exact solution is available is employed. A more complex example involving three scaled boundary subdomains is also addressed. The rates of convergence of these examples under p‐refinement are compared with the corresponding rates of convergence achieved when uniform h‐refinement is used, allowing direct comparison of the computational cost of the two approaches. The results show that it is advantageous to use higher‐order elements, and that higher rates of convergence can be obtained using p‐refinement instead of h‐refinement. Copyright © 2005 John Wiley & Sons, Ltd.
An adaptive finite element method for transient compressible flows
Authors: Probert J. , Hassan O. , Peraire J. , Morgan K. 
Published: October 2005

AbstractAn adaptive finite element method for the solution of time dependent strongly compressible flows in two dimensions is described. The computational domain is represented by an unstructured assembly of linear triangular elements and the mesh adaptation is achieved by local regeneration of the grid, using an error estimation procedure coupled to an automatic triangular mesh generator. Problems involving shock propagation are solved to illustrate the numerical performance of the proposed approach.
Analysis of orthogonal metal cutting processes
Authors: Tyan T. , Yang Wei H. 
Published: October 2005

AbstractThe orthogonal metal cutting process for a controlled contact tool is simulated using a limit analysis theorem. The basic principles are stated in the form of a primal optimization problem with an objective function subjected to constraints of the equilibrium equation, its static boundary conditions and a constitutive inequality. An Eulerian reference co‐ordinate is used to describe the steady state motion of the workpiece relative to the tool. Based on a duality theorem, a dual functional bounds the objective functional of the primal problem from above by a sharp inequality. The dual formulation seeks the least upper bound and thus recovers the maximum of the primal functional theoretically. A finite element approximation of the continuous variables in the dual problem reduces it to a convex programming. Since the original dual problem admits discontinuous solutions in the form of bounded variation functions, care must be taken in the finite element approximation to account for such a possibility. This is accomplished by a combined smoothing and successive approximation algorithm. Convergence is robust from any initial iterate. Results are obtained for a wide range of control parameters including cutting depth, rake angle, rake length and friction. The converged solutions provide information on cutting force, chip thickness, chip stream angle and shear angle which agree well both in values and trend with the published data. But the available data represent only a small subset in the range of parameters exhaustively investigated in this paper.
Structural properties of chalcopyrite thin films studied by Raman spectroscopy
Authors: Papadimitriou D. , Esser N. , Xue C. 
Published: October 2005

AbstractThis paper reviews the structural properties of ternary chalcopyrite absorbers for solar‐cell device applications studied by Raman Spectroscopy. Raman mode assignment in CuGaSe2 is reviewed according to the results of previous and present Raman and IR spectroscopic studies. The compositional dependence of Raman modes, in particular, the composition dependent frequency shift of the A1‐mode, is suggested for the analysis of the chalcopyrite film structure. Order and disorder effects are discussed with reference to the excitation of phonon modes assigned to Cu–Au ordered phases and to defect related phases, respectively. Phase separation effects associated with the formation of secondary microcrystalline CuxSe‐ or CuxS‐phases and the observation of Raman scattering from these phases are also discussed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Scattering of light from metallic films with a corrugated surface: Magnetic field effects in the Voigt geometry
Authors: Jacobo‐Escobar J. H. , Cocoletzi Gregorio H. 
Published: October 2005

AbstractWe study the scattering of electromagnetic waves from a corrugated surface of a metallic film, which has a flat surface in contact with a semi‐infinite superlattice. External magnetic fields are accounted for, in the Voigt configuration, to calculate the scattered field amplitudes up to first order on the corrugation height. Two‐zero order minima and two‐first order peaks are obtained as a result of the coupling of the incident light with the magnetoplasmons at the corrugated surface. The peaks are associated with the p = ±1 terms in the expansion of the fields. We find that the splitting of the minima is affected by the external field and the superlattice. In the absence of the superlattice the external field splits the symmetric and antisymmetric film modes, however, the presence of the superlattice closes the gap. The gap also depends on the angle of incidence. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of sample size formulae for 2 × 2 cross‐over designs applied to bioequivalence studies
Authors: Siqueira Arminda Lucia , Whitehead Anne , Todd Susan , Lucini María M. 
Published: October 2005

AbstractWe consider the comparison of two formulations in terms of average bioequivalence using the 2 × 2 cross‐over design. In a bioequivalence study, the primary outcome is a pharmacokinetic measure, such as the area under the plasma concentration by time curve, which is usually assumed to have a lognormal distribution. The criterion typically used for claiming bioequivalence is that the 90% confidence interval for the ratio of the means should lie within the interval (0.80, 1.25), or equivalently the 90% confidence interval for the differences in the means on the natural log scale should be within the interval (−0.2231, 0.2231). We compare the gold standard method for calculation of the sample size based on the non‐central t distribution with those based on the central t and normal distributions. In practice, the differences between the various approaches are likely to be small. Further approximations to the power function are sometimes used to simplify the calculations. These approximations should be used with caution, because the sample size required for a desirable level of power might be under‐ or overestimated compared to the gold standard method. However, in some situations the approximate methods produce very similar sample sizes to the gold standard method. Copyright © 2005 John Wiley & Sons, Ltd.
Symbolic execution of floating‐point computations
Authors: Botella Bernard , Gotlieb Arnaud , Michel Claude 
Published: October 2005

AbstractSymbolic execution is a classical program testing technique which evaluates a selected control flow path with symbolic input data. A constraint solver can be used to enforce the satisfiability of the extracted path conditions as well as to derive test data. Whenever path conditions contain floating‐point computations, a common strategy consists of using a constraint solver over the rationals or the reals. Unfortunately, even in a fully IEEE‐754‐compliant environment, this leads not only to approximations but also can compromise correctness: a path can be labelled as infeasible although there exists floating‐point input data that satisfy it. In this paper, the peculiarities of symbolic execution of programs with floating‐point numbers are addressed. Issues in the symbolic execution of this kind of program are carefully examined and a constraint solver is described that supports constraints over floating‐point numbers. Preliminary experimental results demonstrate the value of the approach proposed. Copyright © 2005 John Wiley & Sons, Ltd.
Quinolinic acid reduces the antioxidant defenses in cerebral cortex of young rats
Authors: Leipnitz Guilhian , Schumacher Cristiana , Scussiato Karina , Dalcin Karina B. , Wannmacher Clóvis M.D. , Wyse Angela T.D. , Dutra‐Filho Carlos S. , Wajner Moacir , Latini Alexandra 
Published: October 2005

AbstractQuinolinic acid (QA), the major metabolite of the kynurenine pathway, is found at increased concentrations in brain of patients affected by various common neurodegenerative diseases, including Huntington's disease and Alzheimer's disease. Recently, a role for QA in the pathophysiology of glutaric acidemia type I (GAI) was postulated. Considering that oxidative stress has been recently involved in the pathophysiology of the brain injury in these neurodegenerative disorders; in the present study, we investigated the in vitro effect of QA on various parameters of oxidative stress, namely total radical‐trapping antioxidant potential (TRAP), total antioxidant reactivity (TAR), glutathione (GSH) levels, thiobarbituric acid‐reactive substances (TBA‐RS) measurement and chemiluminescence in cerebral cortex of 30‐day‐old rats. QA diminished the brain non‐enzymatic antioxidant defenses, as determined by the reduced levels of TRAP, TAR and GSH. We also observed that QA significantly increased TBA‐RS and chemiluminescence. Therefore, in vitro QA‐treatment of rat cortical supernatants induced oxidative stress by reducing the tissue antioxidant defenses and increasing lipid oxidative damage, probably as a result of free radical generation. In addition, we examined the effect of QA on TBA‐RS levels in the presence of glutaric acid (GA) and 3‐hydroxyglutaric acid (3HGA), which are accumulated in GAI, as well as in the presence of 3‐hydroxykynurenine (3HK), a tryptophan metabolite of the kynurenine pathway with antioxidant properties. It was verified that the single addition of QA or GA plus 3HGA to the incubation medium significantly stimulated in vitro lipid peroxidation. Furthermore, 3HK completely prevented the TBA‐RS increase caused by the simultaneous addition of QA, GA and 3HGA. Taken together, it may be presumed that QA induces oxidative stress in the brain, which may be associated, at least in part, with the pathophysiology of central nervous system abnormalities of neurodegenerative diseases in which QA accumulates.
Telemedicine and robotics: Paving the way to the globalization of surgery
Authors: Senapati S. , Advincula A.P. 
Published: October 2005

AbstractThe concept of delivering health services at a distance, or telemedicine is becoming an emerging tool for the field of surgery. For the surgical services, telepresence surgery through robotics is gradually being incorporated into health care practices. This article will provide a brief overview of the principles surrounding telemedicine and telepresence surgery as they specifically relate to robotics. Where limitations have been reached in laparoscopy, robotics has allowed further steps forward. The development of robotics in medicine has been a progression from passive to immersive technology. In gynecology, the utilization of robotics has evolved from the use of Aesop®, a robotic arm for camera manipulation, to full robotic systems such as Zeus®, and the daVinci® surgical system. These systems have not only been used directly for a variety of procedures but have also become a useful tool for conferencing and the mentoring of surgeons from afar. As this mode of technology becomes assimilated into the culture of surgery and medicine globally, caution must be taken to carefully navigate the economic, legal and ethical implications of telemedicine. Despite the challenges faced, telepresence surgery holds promise for more widespread applications.
interpretation of vertebral growth marks as annuli in the sandbar shark carcharhinus plumbeus: analysis of vertebrae of captive specimens
Authors: torres borja , morey gabriel , tomás javier 
Published: October 2005

four captive specimens of sandbar shark carcharhinus plumbeus from the l'oceanogràfic aquarium (valencia, spain) were studied: one adult female (192 cm total length [tl]) reared for five months, her two new born pups (a female, 61 cm tl and a male, 60 cm tl), and one juvenile female, born in captivity, dead at nine months of age (90 cm tl). comparative measurements of length and diameter of vertebrae from three different regions of the vertebral column showed that vertebrae above the pelvic fins (nos. 59–63) are the biggest in this species. consequently, these vertebrae are preferred for age estimation given that growth marks are easier to identify. the only present mark in the vertebrae of the two neonate specimens was at the edge and was interpreted as the birth mark. a mark at a similar distance was present in the vertebrae of the juvenile and adult females.adult female vertebrae analysis shows 23 marks without any variation in the banding pattern distribution during free-range growth and short period of captivity. the juvenile individual shows two clear growth marks developed after birth. the presence of these marks in a 9-month old individual suggests that the counting of all vertebral growth marks as annuli may result in the overestimation of age for this shark species.
Magnetic resonance imaging in pediatric elbow fractures
Authors: Pudas T. , Hurme T. , Mattila K. , Svedström E. 
Published: October 2005

Purpose: Magnetic resonance imaging (MRI) evaluation of pediatric elbow trauma with or without a visible fracture on radiography. Material and Methods: MRI was performed in the acute phase in 25 children with an elbow injury. Nine patients with an elbow effusion only on radiographs and 16 with a fracture or luxation seen on radiographs underwent subsequent MRI. No sedation was used. Results: MRI revealed eight occult fractures (89%) in seven out of nine patients who had only an effusion on radiographs. Based on MRI findings, septic arthritis was suspected in one patient. Two patients out of five with a supracondylar fracture on the radiograph had a cartilage lesion in the humerus. MRI depicted a 3-mm gap on the articular surface in two patients with a lateral condyle fracture, a more accurate fracture location in two patients than the radiographs, and an additional occult fracture in two patients. MRI showed a fracture not seen on radiographs in two of three patients with prior luxation. Conclusion: MRI is a sensitive and accurate method in the diagnosis of pediatric elbow injuries, especially when only an effusion is present on radiographs. Occult fractures are more common in pediatric patients with elbow injury than reported earlier.
Functional magnetic resonance imaging at 3t as a clinical tool in patients with intracranial tumors
Authors: van Westen D. , Skagerberg G. , Olsrud J. , Fransson P. , Larsson E.-M. 
Published: October 2005

Purpose: To investigate the potential of functional magnetic resonance imaging (fMRI) at 3T as a clinical tool in the preoperative evaluation of patients with intracranial tumors. High magnetic field strength such as 3T is of benefit for fMRI because signal-to-noise ratio and sensitivity to susceptibility changes are field-strength-dependent. Material and Methods: Twenty patients with tumors close to eloquent sensorimotor or language areas were studied. Motor, sensory, and two language paradigms (word generation, rhyming) were used; their effectiveness was determined as the percentage of patients in whom the functional area of interest was activated. Activation maps were calculated and their quality rated as high, adequate, or insufficient. The influence of fMRI on the neurosurgical decision regarding operability, surgical approach, and extent of the resection, was assessed. Results: Paradigm effectiveness was 90% for motor and 95% for sensory stimulation, and varied from 79% to 95% for word generation and rhyming in combination. Ninety percent of the activation maps held high or adequate quality. fMRI proved useful: in the decision to operate (9 patients), in the surgical approach (13 patients), and in extent of the resection (12 patients). Conclusion: fMRI at 3T is a clinically applicable tool in the work-up of patients with intracranial tumors.
Measuring heroin use in methadone maintenance programmes
Authors: Howard Kirsten , Bell James , Christie Macdonald J. 
Published: October 2005

AbstractThis study compares a number of self‐reported measures of drug use with the results of urine testing in a group of patients receiving methadone maintenance treatment. One hundred and twenty‐nine subjects were interviewed and 4‐5 months later, a second interview was obtained from 87 of these. At each interview subjects were asked about drug use on each of the preceding 7 days and also about the number of days of drug use in the previous month. It was found that most patients were continuing to use heroin, usually fairly infrequently. Direct comparisons of urine test results and self‐reported drug use indicate substantial positive correlations. However, there was a tendency for self‐report to underestimate drug use in this patient sample. It appears that urine testing is the single most useful measure of drug use. This supports the notion that it is a valid tool in evaluation research. However, the combination of self‐report and urine tests provides more information about drug use than any single measure.
Alcoholics' beliefs about responsibility for, and recovery from, their condition
Authors: West Robert , Power Danielle 
Published: October 2005

AbstractA study was carried out with a sample of in‐patients and out‐patients in an alcohol treatment programme examining beliefs about where responsibility lay for their condition and recovery from it. Brickman et al. [1] proposed a framework for understanding these beliefs consisting of four ‘models’. In each model responsibility for causing the problem and for resolving it is considered either to lie with the individual or with other factors. The results indicated that the alcoholics' beliefs could not readily be understood in terms of this framework. As regards the cause of their condition, belief in the role of luck, personal responsibility and acceptance of a disease model emerged as independent factors. With regard to responsibility for recovery, belief in personal responsibility, the value of treatment and support and the importance of motivation emerged as separate factors. Belief in personal responsibility for causing the problem was significantly associated with acceptance of responsibility for recovery. Adoption of a disease model was negatively associated with belief in the importance of motivation in recovery. Treatment satisfaction was positively correlated with belief in the importance of treatment and support but not other dimensions. Younger patients tended to accept a lower level of personal responsibility for their condition. The results indicate the alcoholics tend to adopt quite specific beliefs about their condition and that satisfaction with a particular treatment regimen is related to belief in the value of treatment rather than any particular model concerning where responsibility for their condition and recovery from it lies.
Reviewing the needs of unemployed youth in smoking intervention programmes
Authors: Stanton Warren R. , Gillespie Amaya M. , Lowe John B. 
Published: October 2005

AbstractIn Australia, the impact of unemployment on adolescent smoking behaviour continues to present a major public health problem. Traditional prevention programmes in both primary and secondary schools appear to be achieving a delay in the onset of smoking. However, smoking rates of young people who are unemployed are unacceptably higher than those of in‐school youth. This paper provides a review of the published literature, showing that there has been little effort to address smoking patterns or experiences of quitting for this target group. While the provision of employment opportunities or skill training for this group is important, these strategies will not eliminate the problem of smoking. Steps must be taken to encourage research into the development of tailored programmes for unemployed youth who smoke. These programmes must be carefully considered and evaluated and meet the needs of this diverse group of young people.
The use of opioid medications in patients with chronic non‐malignant pain who have drug dependence
Authors: Sellman J. D. , Kendall N. A. S. , Macleod A. D. 
Published: October 2005

AbstractThe use of opioid medications in the management of painful medical conditions is currently being ‘rediscovered’. However, although drug‐dependent patients are likely to be over‐represented in the chronic pain population and are also arguably less likely to respond to non‐pharmacological interventions for chronic pain, opioid medications are considered to be relatively contraindicated for such a patient group. This paper explores, first, the background to this situation before proposing a set of interim guidelines for the use of opioid medications in the management of chronic pain in drug‐dependent patients in order to protect access to this treatment strategy for this difficult patient group, while data from controlled studies are obtained for more definitive policy formation.
Strategic developments in drug and alcohol policy*
Authors: WILLIAMS GERARD 
Published: October 2005

AbstractThis review of recent developments in drug and alcohol policy investigates the reasons behind those developments and questions some of the directions in which this policy is taking the services. There is a possibility that services may become superficial and it appears that there are clients who are effectively denied public health services. [Williams G. Strategic developments in drug and alcohol policy Drug Alcohol Rev 1995; 14:231–234].