bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computational continua
Authors: Fish Jacob , Kuznetsov Sergey 
Published: May 2010

AbstractWe develop a new coarse‐scale continuum formulation hereafter referred to as computational continua. By this approach, the coarse‐scale governing equations are stated on a so‐called computational continua domain consisting of disjoint union of computational unit cells, positions of which are determined to reproduce the weak form of the governing equations on the fine scale. The label ‘computational’ is conceived from both theoretical and computational considerations. From a theoretical point of view, the computational continua is endowed with fine‐scale details; it introduces no scale separation; and makes no assumption about infinitesimality of the fine‐scale structure. From computational point of view, the computational continua does not require higher‐order continuity; introduces no new degrees‐of‐freedom; and is free of higher‐order boundary conditions. The proposed continuum description features two building blocks: the nonlocal quadrature scheme and the coarse‐scale stress function. The nonlocal quadrature scheme, which replaces the classical Gauss (local) quadrature, allows for nonlocal interactions to extend over finite neighborhoods and thus introduces nonlocality into the two‐scale integrals employed in various homogenization theories. The coarse‐scale stress function, which replaces the classical notion of coarse‐scale stress being the average of fine‐scale stresses, is constructed to express the governing equations in terms of coarse‐scale fields only. Perhaps the most interesting finding of the present manuscript is that the coarse‐scale continuum description that is consistent with an underlying fine‐scale description depends on both the coarse‐scale discretization and fine‐scale details. As a prelude to introducing the computational continua framework, we unveil the relation between the generalized continua and higher‐order mathematical homogenization theory and point out to their limitations. This serves as motivation to the main part of the manuscript, which is the computational continua formulation. Copyright © 2010 John Wiley & Sons, Ltd.
Inelastic analysis of granular interfaces via computational contact homogenization
Authors: Temizer İ. , Wriggers P. 
Published: May 2010

AbstractThe macroscale response of granular contact interfaces is investigated. In order to circumvent the difficulties associated with a direct resolution of such heterogeneous contact problems, where highly mobile particles residing between a deformable body and a rigid surface govern the microscale dynamics, a space–time contact homogenization methodology is developed. The overall approach is based on a separation of spatial as well as temporal scales and proposes an idealized purely frictional macroscale response. The induced macroscale dissipation is directly associated with the microscale dissipation mechanisms due to (i) an inelastic constitutive response for the boundary layer of the deformable body and (ii) frictional interaction among the components of the three‐body contact system. The consequences of a viscoelastic boundary layer that sustains damage due to highly localized deformation in the vicinity of the particles are investigated extensively within a fully nonlinear computational setting that accounts for incompressibility. The effective coefficient of friction that is induced by the homogenization methodology as the fundamental macroscale observable is found to be of a non‐Amontons as well as a non‐Coulomb type. The proposed analysis framework is amenable to a multiscale implementation within a coupled micro–macro approach and yields insight into the macroscopic dynamics of similar heterogeneous interfaces with varying degrees of mobility associated with the roughness features. Copyright © 2010 John Wiley & Sons, Ltd.
Topological derivative for multi‐scale linear elasticity models applied to the synthesis of microstructures
Authors: Amstutz S. , Giusti S. M. , Novotny A. A. , de Souza Neto E. A. 
Published: May 2010

AbstractThis paper proposes an algorithm for the synthesis/optimization of microstructures based on anexactformula for the topological derivative of the macroscopic elasticity tensor and a level set domain representation. The macroscopic elasticity tensor is estimated by a standard multi‐scale constitutive theory where the strain and stress tensors are volume averages of their microscopic counterparts over a representative volume element. The algorithm is of simple computational implementation. In particular, it does not require artificial algorithmic parameters or strategies. This is in sharp contrast with existing microstructural optimization procedures and follows as a natural consequence of the use of the topological derivative concept. This concept provides the correct mathematical framework to treat topology changes such as those characterizing microstuctural optimization problems. The effectiveness of the proposed methodology is illustrated in a set of finite element‐based numerical examples.Copyright © 2010 John Wiley & Sons, Ltd.
Multigrid solver with automatic mesh refinement for transient elastoplastic dynamic problems
Authors: Biotteau E. , Gravouil A. , Lubrecht A. A. , Combescure A. 
Published: May 2010

AbstractThis paper presents an adaptive refinement strategy based on a hierarchical element subdivision dedicated to modelling elastoplastic materials in transient dynamics. At each time step, the refinement is automatic and starts with the calculation of the solution on a coarse mesh. Then, an error indicator is used to control the accuracy of the solution and a finer localized mesh is created where the user‐prescribed accuracy is not reached. A new calculation is performed on this new mesh using the non‐linear ‘Full Approximation Scheme’ multigrid strategy. Applying the error indicator and the refinement strategy recursively, the optimal mesh is obtained. This mesh verifies the error indicator on the whole structure. The multigrid strategy is used for two purposes. First, it optimizes the computational cost of the solution on the finest localized mesh. Second, it ensures information transfer among the different hierarchical meshes. A standard time integration scheme is used and the mesh is reassessed at each time step. Copyright © 2010 John Wiley & Sons, Ltd.
The statistical second‐order two‐scale method for mechanical properties of statistically inhomogeneous materials
Authors: Han Fei , Cui Junzhi , Yu Yan 
Published: May 2010

AbstractA class of random composite materials with statistically inhomogeneous microstructure, for example, functionally graded materials is considered in this paper. The microstructures inside a component are gradually varying in the statistical sense. In view of this particularity, a novel statistical second‐order two‐scale (SSOTS) method is presented to predict the mechanical properties, including stiffness, and elastic limit. To develop this method, the microstructures of statistically homogeneous, and inhomogeneous materials are represented. In addition the SSOTS formulas are derived based on normalized cell depending on the position variables by a constructing way, and the algorithm procedure is described. The mechanical properties of the different inhomogeneous materials are evaluated. The numerical results are compared with the experimental findings. It shows that the SSTOS method is effective. Copyright © 2010 John Wiley & Sons, Ltd.
A new approach to plate theory based on through‐thickness homogenization
Authors: Guiamatsia I. 
Published: May 2010

AbstractA new approach to linear plate theory for layered structures is introduced. The new theory distances itself from the classical strategy where through the thickness displacement functions are assumed a priori. Instead, the homogenization is based on a single assumption that the plate response is a superposition of fundamental states. An equivalent single‐layer (ESL) formulation is presented, which, for the first time, allows accurate three‐dimensional stress and strain fields to be recovered through a postprocessing strategy that is consistent with the theory's assumptions. Copyright © 2010 John Wiley & Sons, Ltd.
Inverse finite element method for large‐displacement beams
Authors: Albanesi Alejandro E. , Fachinotti Víctor D. , Cardona Alberto 
Published: May 2010

AbstractA finite element model for the inverse analysis of large‐displacement beams in the elastic range is presented. The model permits determining the initial shape of a beam such that it attains the given design shape under the effect of service loads. This formulation has immediate applications in various fields such as compliant mechanism design where flexible links can be modeled as large‐displacement beams. Numerical tests for validation purposes are given, together with two design applications of flexible mechanisms with distributed compliance: a flexible gripper and a flexible S‐type clutch. Copyright © 2010 John Wiley & Sons, Ltd.
Matrix‐Padé via Lanczos solutions for vibrations of fluid–structure interaction
Authors: Liew Haw‐Ling , Pinsky Peter M. 
Published: May 2010

AbstractFor multiple‐frequency full‐field solutions of the boundary value problem describing small fluid–structure interaction vibration superimposed on a nominal state with prestress, we propose an efficient reduced order method by constructing the full‐field matrix‐Padé approximant of its finite element matrix function. Exploiting the matrix‐Padé via Lanczos connection, the Padé coefficients are computed in a stable and efficient way via an unsymmetric, banded Lanczos process. The full‐field Padé‐type approximant is the result of one‐sided projection onto Krylov subspace, we established its order of accuracy, which is not maximal. The superiority of this method in terms of various problem dimensions and parameters is established by complexity analysis via flop counts. Numerical examples obtained by using a model problem verified the accuracy of this full‐field matrix‐Padé approximant. Copyright © 2010 John Wiley & Sons, Ltd.
Photovoltaics literature survey (no. 78)
Authors: Shrestha Santosh 
Published: May 2010

AbstractIn order to help keep readers up‐to‐date in the field each issue of Progress in Photovoltaics will contain a list of recently published journal articles most relevant to its aims and scope. This list is drawn from an extremely wide range of journals, including IEEE Transactions on Electron Devices, Journal of Applied Physics, Applied Physics Letters, Progress in Photovoltaics and Solar Energy Materials and Solar Cells. To assist the reader, the list is separated into broad categories, but please note that these classifications are by no means strict. Also note that inclusion in the list is not an endorsement of a paper's quality. If you have any suggestions please email Santosh Shrestha at mailto:s.shrestha@unsw.edu.au. magnified image
Proteome profiling reveals gender differences in the composition of human serum
Authors: Miike Koichiro , Aoki Masashi , Yamashita Ryo , Takegawa Yumiko , Saya Hideyuki , Miike Teruhisa , Yamamura Ken‐ichi 
Published: May 2010

AbstractProteome analysis using human serum is a technological advancement that will enable the discovery of novel biomarkers and biomarker patterns of various human diseases. Although proteome analysis using serum has potential in disease prevention, early diagnosis and treatment of diseases, and evaluation of pharmacotherapies, this technology is still in its infancy. Thus, we sought to develop an advanced method of conducting proteome analysis on human serum. In this study, we report the development of the semi‐comprehensive protein analytical technique, which involves the systematic use of iTRAQ labeling, HPLC, nano‐LC and MS. We compared the composition of the serum proteome in males and females using this technique and detected gender‐based differences in serum protein composition. This technology will enable the generation of databases that may ultimately lead to the discovery of specific biomarkers or biomarker patterns of various diseases.
Pressure‐rate product and phase angle as measures of acute inspiratory upper airway obstruction in rhesus monkeys
Authors: Ross Patrick A. , Hammer Jürg , Khemani Robinder , Klein Max , Newth Christopher J.L. 
Published: May 2010

AbstractRationaleThere are limited validated, objective, and minimally invasive techniques for the bedside evaluation of upper airway obstruction (UAO) in sick infants, despite its frequency in pediatric medicine. Prior techniques include pressure‐rate product (PRP), a product of esophageal pressure and respiratory rate and phase angles (PAs), a measure of asynchrony between ribcage and abdominal respiratory movements in infants with UAO. The purpose of this study is to validate the PRP and compare it to a previously validated PA in rhesus monkeys.MethodsCalibrated resistors were applied to the inspiratory limb of 10 anesthetized, intubated, and spontaneously breathing rhesus monkeys (weight 8.7 ± 2.5 kg). Airway pressure, respiratory rate, PAs, heart rate, and oxygen saturation were recorded. Obstruction was applied in random order as 0, 5, 20, 200, 500, and 1,000 cmH2O/L/sec for 2‐min periods, the last 15 sec (10–20 breaths) were analyzed for each timeframe.ResultsPA increased significantly at the 200 cmH2O/L/sec level but it reached a plateau above 500 cmH2O/L/sec. PRP rose progressively and was significantly different at all levels of obstruction. Esophageal pressure change was progressively and statistically significantly different from baseline and each other at 200, 500, and 1,000 cmH2O/L/sec (P < 0.001).ConclusionsIn this model of UAO, PRP tracks increasing inspiratory load better than PA. PRP continued to be linear up through the highest inspiratory resistance where the change in PA reached a plateau before the highest load. The assessment of esophageal pressure changes may offer the simplest objective measure of UAO. Pediatr Pulmonol. 2010; 45:639–644. © 2010 Wiley‐Liss, Inc.
Children with corrected or palliated congenital heart disease on home mechanical ventilation
Authors: Edwards Jeffrey D. , Kun Sheila S. , Keens Thomas G. , Khemani Robinder G. , Moromisato David Y. 
Published: May 2010

AbstractInfants and children with surgically corrected or palliated congenital heart disease (CHD) are at risk for chronic respiratory failure, necessitating home mechanical ventilation (HMV) via tracheostomy. However, very little data exists on this population or their outcomes. We conducted a retrospective chart review of all children with CHD enrolled in the Childrens Hospital Los Angeles HMV program between 1994 and 2009. Data were collected on type of heart lesion, surgeries performed, number of failed extubations, timing of tracheostomy, mortality, length of time on HMV, weaning status, associated co‐morbidities, and Risk Adjusted classification for Congenital Heart Surgery (RACHS‐1) category. Thirty‐five children were identified; six with single ventricle anatomy, who received palliative procedures. Twenty‐three (66%) patients are alive; 8 (23%) living patients have been weaned off HMV. Twelve (34%) patients are deceased. The incidence of mortality for single ventricle patients was 50%, and only one of the surviving children has received final palliation and weaned off HMV. Eight of nine patients (89%) with a RACHS score ≥4 died, and none have been weaned off of HMV. The 5‐year survival for all CHD HMV patients was 68%; 90% for patients with RACHS ≤3; and 12% for patients with score ≥4. Children with more complex lesions, as demonstrated by single ventricle physiology or greater RACHS scores, had higher mortality rates and less success weaning off HMV. This case series suggests that caregivers should give serious consideration to the type of heart defect as they advise families considering HMV in children with CHD. Pediatr Pulmonol. 2010; 45:645–649. © 2010 Wiley‐Liss, Inc.
CMV pneumonia in HIV‐infected ventilated infants
Authors: Goussard P. , Kling S. , Gie R.P. , Nel E.D. , Heyns L. , Rossouw G.J. , Janson J.T. 
Published: May 2010

AbstractBackgroundThe contributing role of cytomegalovirus (CMV) in infants treated for Pneumocystis jiroveci pneumonia (PJP) is unknown. High dose steroids used in the treatment of PJP may further immunocompromise these infants contributing to the development of CMV pneumonia.AimThe aim of this study was to determine the role of CMV pneumonia in infants being ventilated for suspected PJP.MethodsIn this prospective study HIV infected infants being treated with trimethoprim–sulfamethoxazole (TMP/SMX) and ventilated for suspected PJP were included if they had not responded to treatment. Open lung biopsy was performed if there was no improvement in ventilatory requirements.ResultsTwenty‐five HIV positive infants with a mean age of 3.3 months were included. Lung biopsy was performed in 17 (68%) and post‐mortem lung tissue was obtained in 8 (32%). After evaluation of the histology, immunohistochemistry, and viral cultures from lung tissue, the most likely causes of pneumonia were: CMV and PJP dual infection 36% (n = 9), CMV pneumonia 36% (n = 9), and PJP 24% (n = 6). The pp65 test for CMV antigen was falsely negative in 24%. The mean blood CD4 count was 287/µl. There was an association between the CD4 lymphocyte status and the final diagnosis, with the CMV and PJP group (CD4 110/µl) having the lowest CD4 status (P = 0.0128). Pediatric Intensive Care Unit (PICU) mortality was 72% (n = 18) and in hospital mortality 88%.ConclusionOf the ventilated infants failing to respond to treatment, 72% had histologically confirmed CMV pneumonia, probably accounting for the high mortality in this cohort. The incidence of CMV disease in HIV infected infants being ventilated for severe pneumonia warrants that ganciclovir is used empirically until CMV disease is excluded. The role of lung biopsy in these circumstances needs to be researched. Pediatr Pulmonol. 2010; 45:650–655. © 2010 Wiley‐Liss, Inc.
Voriconazole inhibition of vitamin A metabolism: Are adverse events increased in cystic fibrosis patients?
Authors: Cheng Matthew Pellan , Paquette Katryn , Lands Larry C. , Ovetchkine Philippe , Théoret Yves , Quach Caroline 
Published: May 2010

AbstractBackgroundAs Voriconazole is being used more frequently in cystic fibrosis (CF) patients, we aimed to describe the adverse events associated with voriconazole treatment in this population.MethodsWe performed a retrospective cohort study of all children with CF who received voriconazole between September 2006 and August 2008.ResultsFive of six CF patients receiving treatment developed photosensitivity, whereas all six patients reported visual disturbances. We report two clinical cases of particular interest: a 7‐year‐old boy developed striking erythema in the face and upper thorax; a 16‐year‐old girl who reported unexpected visual disturbances, including scotomas and tunneling vision.ConclusionSignificant adverse effects of voriconazole were noted in all treated CF patients. We speculate that this may be due to suppression of activity of hepatic enzymes involved in all transretinonic acid metabolism coupled with vitamin A supplementation in CF. Consideration should be given to reducing vitamin A supplementation during voriconazole treatment. Pediatr Pulmonol. 2010; 45:661–666. © 2010 Wiley‐Liss, Inc.
Community‐acquired Moraxella catarrhalis pneumonia in previously healthy children
Authors: Sy Magdalena G. , Robinson Joan L. 
Published: May 2010

AbstractBackgroundThe aim of this study was to determine if Moraxella catarrhalis is a common cause of community acquired pneumonia in children with no chronic medical problems. A secondary goal was to describe the clinical features of children with M. catarrhalis pneumonia.MethodsA systematic literature search was conducted for (i) case series of pediatric community‐acquired pneumonia (CAP) where one or more diagnostic tests for M. catarrhalis were applied to all cases and (ii) case reports of previously healthy children with proven M. catarrhalis pneumonia.ResultsThere were nine case series describing a total of 1,500 children with CAP. The number of children tested and yield was as follows: blood cultures 0/402 (0%); sputum cultures 15/157 (10%); nasopharyngeal, or postnasal cultures 129/521 (25%); sputum or nasopharyngeal cultures 0/74 (0%) (one study allowed either); nucleic acid amplification testing 2/100 (2%); serology 30/976 (3%). There were eight case reports of CAP with M. catarrhalis in previously well children. Children were ages 3 weeks to 7 years of age (median 14 months). Six of 8 (75%) children required mechanical ventilation. All survived.ConclusionIt is common to detect M. catarrhalis in upper respiratory secretions in children with pneumonia, but bacteremia or seroconversion is rare. There are only eight well‐documented case reports CAP due to M. catarrhalis in previously well children, with there being no distinctive features in the eight cases described to date. This organism is likely a rare cause of CAP in previously healthy children. Pediatr Pulmonol. 2010; 45:674–678. © 2010 Wiley‐Liss, Inc.
Skeletal dysplasias: Evaluation with impulse oscillometry and thoracoabdominal motion analysis
Authors: Rodriguez M.E. , Mackenzie William G. , Ditro Colleen , Miller Thomas L. , Chidekel Aaron , Shaffer Thomas H. 
Published: May 2010

AbstractBackgroundChildren with skeletal dysplasia (SD) often have pulmonary disease, which can be life threatening. In clinical practice, chest wall and formal respiratory function tests are difficult to perform owing to the small size and cooperation. The objective of this study was to demonstrate distinct thoracopulmonary function patterns in children with SD.MethodsWe conducted a retrospective study reviewing pulmonary function tests from 17 patients with the diagnosis of SD. Three subgroups were studied: Morquio syndrome (MS), metatropic–spondylocostal dysplasia (MSD), and unspecified skeletal dysplasias (SDU). Rib cage contribution to tidal volume excursions (%RC), phase angle (Phθ), phase relation during total breath (PhRTB), respiratory resistance (Rrs5–35 Hz), respiratory reactance (Xrs5–35 Hz), resonant frequency, and their frequency–dependency were analyzed. Values were age‐matched and height‐matched to reference values of healthy subjects.ResultsThere was a decrease in %RC and an increase in PhRTB (P < 0.05) in the SD group. %RC differed between subgroups [MS: 46.4 ± 1.8% SE, MSD: 18.4 ± 2.6% SE, SDU: 27.5 ± 5.2% SE (P < 0.05)]; Phθ was within reference values only in MS, which exhibited a decrease in Xrs at 5 Hz (P < 0.05) and an increase in Rrs independent of the frequency. SDU showed a decrease in Xrs at 35 Hz (P < 0.05), no differences were found in Rrs. In MS, a correlation was found between RC and Rrs at all frequencies (r = −0.98, P < 0.01) and between Xrs5–10 and Phθ (r = −0.93, P < 0.05).ConclusionsThoracoabdominal dysfunction was associated with altered chest wall reactance at high frequencies in a subgroup of SD patients with abnormal lung reactance and central airway involvement in MS. Pediatr Pulmonol. 2010; 45:679–686. © 2010 Wiley‐Liss, Inc.