bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural Characterization of Protein‐Imprinted Gels Using Lattice Monte Carlo Simulation
Authors: Levi Liora , Srebnik Simcha 
Published: June 2010

AbstractMolecular imprinting is a technique for the creation of artificial recognition sites in synthetic organic or inorganic polymers, formed by cross‐linking in the presence of a template molecule. Removal of the templates leaves cavities that fit the template molecules in size, shape and functionality. Although this technique has been shown to be effective when targeting small rigid molecules, attempts to extend it to larger templates, such as proteins, have failed to show similar success. As opposed to small molecules, proteins are characterized by large size, flexible structure, and large number of functional groups available for recognition. These characteristics, among others, make it impossible to use imprinting procedures of small molecules for protein imprinting. In order to plan new imprinting strategies for proteins, one must reveal the problematic points in the polymerization process of the current methods, which result in low imprinting efficiency. In our research we focus on a bulk imprinting method using radical polymerization of hydrogels, applied to small globular proteins (e.g., lysosyme and cytochrome c). We model the system using lattice Monte Carlo (MC) simulation, using a modified kinetic gelation model (KGM) to simulate the polymerization process, which results in an inflexible protein‐imprinted gel. The effect of initiator molar ratio, polymer volume fraction (VF), cross‐linker density, and protein charge density and distribution on gelation, gel structure, and on the imprinted pore structure and functionality is investigated in the dry state of the gel. It is found that the imprinted pores wrap the template protein more fully and with larger number of linking sites than the non‐imprinted pores. The insertion of non‐template proteins with various charge densities and distributions into the imprinted pores indicates that charge density of the adsorbing protein is the dominant factor influencing the number of linked recognition sites.
Magnetically Induced Heating in Elastomeric Nanocomposites ‐ Theory and Experiment
Authors: Levine Igal , Zvi Regev Ben , Winkler Moritz , Schmidt Annette M. , Gottlieb Moshe 
Published: June 2010

AbstractMagnetic nanoparticles are known to generate heat when exposed to an alternating external magnetic field. A multi‐scale model for the heat generation by magnetic nanoparticles embedded in an elastomeric material has been developed. The model affords the determination of the unsteady‐state temperature profiles in the particles and in the surrounding polymeric medium by numerically solving the equation of energy. We obtained the complete thermal history of the system as a function of all relevant parameters including particle size, particle volume fraction, thermal properties of the particle and the medium, and details of the imposed magnetic field. The predicted results are in good agreement with experimental data obtained on liquid crystalline elastomers.
Enclosure of Secondary Chirality Based on Highly‐Oriented Lipid Aggregates into a Polymer Sheet by Photo‐Induced Polymerization of Polymerizable Monomer Gels
Authors: Takafuji Makoto , Kira Yoshiko , Ishiordori Arata , Hachisako Hiroshi , Sawada Tsuyoshi , Ihara Hirotaka 
Published: June 2010

AbstractThe L‐glutamide derivative with double long‐chain alkyl groups and a pyrenyl head group (Pyr‐lipid) worked as organogelator in benzene and cyclohexane. Gelation was brought about through network formation with well‐developed fibrous aggregates based on lipid membrane‐like highly‐oriented structures. Gelation was observed in polymerizable monomers such as methyl methacrylate (MMA) and styrene (St). Extremely intense CD spectra were observed at the absorption band of pyrenyl group in a monomer solution at gel‐forming temperature, but the intensity decreased remarkably at the sol‐forming temperature. The transparent solid sheet was obtained by photo‐irradiation to the MMA gel in a quartz cell. More than 99% of MMA was polymerized even in the gel state and the weight‐average molecular weight (Mw) of the resultant polymer was 7.2 × 104 g mol−1. CD spectra indicated that chirally‐oriented structures in the gel state were maintained after polymerization of MMA and were stable at the temperature above the original gel‐to‐sol transition temperature. Fluorescence spectra of Pyr‐lipid in the monomer solutions supported that the pyrene excimer was formed in the lipid aggregates and the stabilization of the excimer formation was achieved by polymerization of MMA in the gel state.
Counterion and pH‐Mediated Structural Changes in Charged Biopolymer Gels
Authors: Horkay Ferenc , Basser Peter J. , Hecht Anne‐Marie , Geissler Erik 
Published: June 2010

AbstractDNA solutions and gels exhibit a wide range of phenomena, many of which have not yet been fully understood. In the presence of multivalent counterions, attraction between charged DNA strands occurs. Increasing the concentration of multivalent ions leads to a decrease of the osmotic pressure, and a sufficiently high ion concentration results in the precipitation of the polymer. Replacing the monovalent counterions by hydrogen ions (decreasing the pH) also produces a marked decrease of the osmotic pressure, and at low pH a phase transition takes place. In this paper we analyze osmotic swelling pressure measurements and small‐angle neutron scattering (SANS) measurements made on chemically cross‐linked DNA gels swollen in near physiological salt solutions. The effect of calcium ions is compared with that of decreasing the pH of the equilibrium salt solution. We demonstrate that both the concentration dependence of the osmotic pressure and the SANS response of DNA gels display significant differences in the two cases.
Elastic finite element analysis on cross‐sections of random hollow sphere structures
Authors: Fiedler T. , Kim H. S. , Belova I. V. , Sloan S. W. , Murch G. E. , Öchsner A. 
Published: June 2010

AbstractThis paper addresses elastic analysis based on 2D finite element models for metallic hollow‐sphere structures. In the first part, the influence of micro‐porosity on the elastic behaviour of sintered metallic hollow sphere wall material is investigated. Young's modulus of the metallic hollow sphere wall material is found to linearly decrease with increasing micro‐porosity ranging up to about 45%. In the second part, elastic parameters for metallic syntactic foams (MSF) consisting of thin or thick walled hollow spheres, and for epoxy containing spherical pores are studied. Data obtained from finite element models are compared with theoretical predictions based on the rule of mixtures developed elsewhere and found to be in good agreement with each other for MSF but not for porous epoxy. The shear modulus of MSF with thin‐walled hollow spheres was found to increase with increasing volume fraction of matrix whereas that of MSF with thick walled hollow spheres was found to decrease. Specific Young's modulus of MSF with thin‐walled hollow spheres was also found to increase with increasing foam density whereas that of MSF with thick walled hollow spheres was found to decrease. Poisson's ratio obtained was relatively low for porous epoxy matrix material but high for MSF with thin or thick‐walled hollow spheres.Dieser Artikel beschäftigt sich mit der elastischen Finite‐Elemente‐Analyse zwei‐dimensionaler Modelle von Hohlkugelstrukturen. Im ersten Teil der Arbeit wird der Einfluss von Mikroporosität auf das elastische Verhalten der gesinterten Hohlkugelschale untersucht. Es wurde beobachtet, dass der Elastizitätsmodul des gesinterten Materials linear mit steigender Porosität abnimmt. Der zweite Teil der Arbeit befasst sich mit Hohlkugelstrukturen bestehend aus Hohlkugeln und Epoxidmatrix verschiedener Wandstärkent: dickwandige Hohlkugeln, dünnwandige Hohlkugeln und dem Grenzfallt→ 0 (kugelförmige Einschlüsse ohne Hohlkugelschale). Die Ergebnisse der Finite‐Elemente‐Analyse wurden mit analytischen Modellen verglichen und mit Ausnahme der kugelförmigen Einschlüsse eine gute Übereinstimmung erzielt. Der Schubmodul dünnwandiger Hohlkugelstrukturen nimmt mit zunehmendem Volumenanteil der Epoxidmatrix zu, der Schubmodul von dickwandigen Hohlkugelstrukturen jedoch ab. Die ermittelten Querkontraktionszahlen sind für den Fall kugelförmiger Einschlüsse (t→ 0) vergleichsweise niedrig. Deutlich höhere Ergebnisse wurden für dünn‐ und dickwandige Hohlkugelstrukturen erzielt.
Large deformation of core materials for sandwich panels
Authors: Speich M. , Merkel M. , Öchsner A. 
Published: June 2010

AbstractSandwich panels represent a basic design unit for light weight structures. Sandwich panels typically consist of at least two different materials for core and skin. Within the scope of this paper, the large deformation behaviour of different cellular core materials for sandwich panels is investigated. The large deformation behaviour for different core materials is analysed experimentally by compression tests. We investigate metallic hollow sphere structures (MHSS) and synthetic polyvinyl chloride (PVC) foams. In addition, appropriate computational models are presented to account for the deformation mechanisms and to compare computational to experimental results. With these models we will be able to already validate the future experimental test set‐ups with numerical simulations before the test set‐up is build.Sandwichelemente gelten als Grundstruktur für Leichtbau‐Konstruktionen. Sie bestehen normalerweise aus mindestens zwei verschiedenen Materialien für den Kern und die Deckschichten. Dieser Beitrag befasst sich mit dem Verhalten bei großer Verformung von verschiedenen Kernmaterialien. Dieses Verhalten wird mit einem Druckversuch experimentell für zwei solcher Kernmaterialien untersucht. Die beiden Materialien sind zum einen metallische Hohlkugelstrukturen (MHKS) und zum anderen ein Polyvinylchlorid‐Schaum. Zusätzlich werden dazu passende Simulationsmodelle erstellt, um die experimentell gewonnen Ergebnisse mit solchen aus der FE‐Analyse zu vergleichen. Mit diesen Modellen sind wir in der Lage, zukünftige Test‐Aufbauten bereits vor dem Bau mit Hilfe von numerischer Simulation zu überprüfen.
Tribological performance of polyester composites filled by vegetable oils
Authors: Ibrahim R. A. , Ali W. Y. 
Published: June 2010

AbstractIn the present work, friction coefficients and wear rates of polyester composites reinforced by graphite fiber with different diameters and impregnated by vegetable oils (Corn, Olives, and Sunflower oil) were measured to develop new engineering materials with low friction coefficients and high wear resistance which can be used in industrial applications as bearing materials. It was found thatcomposites of 10 vol.% corn oil and 10 vol.% graphite fibers show relatively low friction coefficientsand low wear rates. Corn and sunflower oil display good tribological behavior of the polyester composites.
Simulation of inhomogeneous models using the finite cloud method
Authors: Burke D. R. , Moslemi‐Tabrizi S. , Smy T. J. 
Published: June 2010

AbstractThe field of computational engineering and experimentation relies very heavily on methods of advanced and accurate model simulation of partial differential equations as found in heat flow, the wave equation, and electromagnetics. A majority of these methods use techniques such as Finite Difference or Finite Elements that require the meshing of the geometric region and knowledge of the connectivity and relationships between each segment. A newly proposed method, the Finite Cloud Method (FCM), removes the need for the onerous and sometimes difficult task of computing this mesh, instead uses shaping functions and a discretized set of partial differential equations based only on the placement of nodes [1]. The ability of the FCM to allow for the distribution of solution points to areas of complexity in a completely free manner could enable faster more accurate simulations. However, initial work has focused on materially homogenous problems and the extension of the technique to models composed of different materials with varying physical properties is needed for practical problems. This study presents a method of formulating the FCM equations such that they allow for the specification of varying material properties and is applied to the heat transfer equation. Results from the work have shown an ability to accurately model complex structures in 3‐dimensions for both transient and steady‐state solutions.
Correlation analysis of MAG robotized welding parameters by the Taguchi technique
Authors: de Figueiredo M. V. , Fernandes A. A. , da Silva L. F. M. 
Published: June 2010

AbstractThe correlation of weld joint geometry and welding process parameters was studied. Carbon steel coupon plates were welded with a six axles robotized MAG welding cell. Taguchi techniques were used to plan the experiments carried out. The statistical analysis of the results showed a correlation between weld penetration and welding current, torch/workpiece distance and welding speed. The weld width and reinforcement were dependent on welding speed, arc voltage and current. Correlations were obtained by means of multiple regression analysis validated by experiments.
Numerical simulation of heat transfer in friction stir welding of 7075‐T6 aluminum alloy and high carbon steel using Arbitrary Lagrangian Eulerian technique
Authors: Esmaily M. , Shokuhfar A. 
Published: June 2010

AbstractThere are various simulation methods of processes having severe plastic deformation. Finite Elements Method is used as an appropriate and precise method in the simulation of such processes. This method is used and completed with Eulerian and Lagrangian formulation. In the present work, the combination of these two methods, namely Arbitrary Lagrangian Eulerian (ALE), has been found to be the best way of simulating events involving severe plastic deformation. The purpose of this article is to analyze the heat transfer process in friction stir welding using ANSYS software and compare the obtained data with experimental results. In this research, palates made of 7075‐T6 Aluminum alloy and high carbon steel were welded and temperature measurement in the main sections was carried out by an accurate and special method during welding. Heat variation measurement was also carried out based on the time the tool operated. The process of heat transfer in friction stir welding of the selected alloys were then simulated, a comparison between simulation and experimental data shows a reasonable conformity between numerical and experimental results.
Corrosion resistance of Ti‐6Al‐4V alloy after diverse surface treatments
Authors: Szewczenko J. , Walke W. , Nowinska K. , Marciniak J. 
Published: June 2010

AbstractResults of the influence of diverse initial surface treatment methods on corrosion resistance of Ti‐6Al‐4V ELI alloy after anodic oxidation are presented in the work. The initial surface treatment consisted of: shot peening, mechanical polishing, sandblasting and electrolytical polishing. The pre‐prepared samples were divided into groups and anodized. As a result of the anodization, different colors were obtained: yellow, violet, blue and celadon. Sample preparation conditions were the same for all the groups. Pitting corrosion tests were realized with the use of the potentiodynamic method by means of recording anodic polarization curves. On the basis of the recorded curves, the characteristic values of corrosion resistance were determined. For the given variants of surface treatment, the XPS (X‐ray Photoelectron Spectroscopy) method was applied in order to appoint the chemical composition of the formed layer. Before and after corrosion tests, SEM (Scanning Electron Microscopy) observations were carried out.
Design of an automotive frame cross member for the hydro‐forming process using computer aided engineering
Authors: Kim K.‐J. , Han C.‐P. , Sung C.‐W. , Lim E.‐J. , Choi B.‐I. , Oh S. , Park J.‐H. , Won S.‐T. , Kim S.‐S. 
Published: June 2010

AbstractHydroforming is a forming technology in which a steel tube is set in a die and formed to fit a specified shape by applying hydraulic pressure from inside the tube while also applying force in the tube axial direction (axial feed). In the present study, the whole process chain of frame component (cross member) simulation and development by hydroforming technology to apply to a high strength steel having a tensile strength of 440 MPa grade is studied. At the part design stage, a feasibility study and process design aided by CAE (Computer Aided Design) to confirm the hydroformability in detail is required. The overall possibility of the hydroformability of the frame part could be examined by cross sectional analyses. Moreover, it is essential to ensure the formability of the tube material in every forming step such as pre‐bending and hydroforming. At the die design stage, all the components of the prototyping tool are designed and the interference with the press is investigated from the geometry. For the improvement of tube thinning, the hydroforming was carried out adding an axial feeding of 45 mm at both ends of the part for supplying materials to the end zone where thinning occurs and retards burst. From this treatment, the thinning of the tube wall was experimentally measured and it was improved by 17.9%. It is in good agreement with the calculation and the position of the maximum thinning corresponds to the result of the simulation.
High‐resolution in vivo imaging of breast cancer by targeting the pro‐invasive integrin αvβ6
Authors: Saha Antonio , Ellison David , Thomas Gareth J , Vallath Sabarinath , Mather Stephen J , Hart Ian R , Marshall John F 
Published: June 2010

AbstractThe integrin αvβ6 is expressed only on epithelia and then usually only during processes of tissue remodelling including cancer, where its high expression correlates with reduced survival. Thus, αvβ6 represents an important target for imaging and therapy of cancer and new molecular‐specific targeting agents are required. We have developed A20FMDV2, a peptide derived from the VP1 coat protein of foot‐and‐mouth‐disease virus that binds specifically and stably to αvβ6. Using a newly generated pair of isogenic human cell lines that differ only in αvβ6 expression, it was shown, using biodistribution and SPECT imaging, that indium‐111‐labelled A20FMDV2 locates specifically to αvβ6‐expressing tissues in vivo, achieving at least seven‐times higher retention in αvβ6‐positive than in αvβ6‐negative tumours. In further studies with MCF10.DCIS.COM and MCF10A.CA1a breast carcinoma cell lines, which express αvβ6 endogenously, the radiopeptide achieved similar levels of tumour retention and permitted excellent discriminatory imaging of tumours. Thus, A20FMDV2 can be used for molecular‐specific targeting of αvβ6 for imaging in vivo the often more aggressive, αvβ6‐positive cancers. In the future, A20FMDV2 could serve also to deliver therapy to these same cancers. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Risk factors for renal failure in pediatric patients with acute myeloid leukemia: A retrospective cohort study
Authors: Fisher Brian T. , Zaoutis Theoklis E. , Leckerman Kateri H. , Localio Russell , Aplenc Richard 
Published: June 2010

AbstractBackgroundIn children receiving treatment for acute myeloid leukemia (AML) there is often concern for the development of acute renal failure (ARF). Despite this, data are limited to define the incidence of ARF in this population. This study aims to evaluate the rate of ARF in AML patients and to delineate the impact of age, race, various co‐morbid conditions and antimicrobial agents on the development of ARF.MethodsA cohort of newly diagnosed AML patients from children's hospitals across the United States was identified using the Pediatric Health Information Systems database. Information regarding demographics, discharge diagnoses, pharmaceutical exposures, and hospital resource utilization were collected for each hospitalization for up to 1 year from AML diagnosis. Cox regression analysis was used to define the hazard ratios for development of ARF by demographic variables, co‐morbid conditions, and exposure to various antimicrobial agents.ResultsWithin 1 year of AML diagnosis, 135 (16.2%) patients were diagnosed with ARF. After adjustment for the presence of co‐morbid conditions, the risk for ARF was greater in older patients and in black patients. Vancomycin exposure duration of greater than 48 hr and carbapenem exposure duration greater than 10 days were associated with an increased risk for ARF.ConclusionARF is a relatively common problem in children with AML. Future studies should address the different risks of ARF by age and race. Empiric therapy with potentially nephrotoxic agents did not increase the risk of nephrotoxicity. Patients on prolonged vancomycin therapy should be monitored closely for development of ARF. Pediatr Blood Cancer. 2010;55:655–661. © 2010 Wiley‐Liss, Inc.
Development and evaluation of an educational interactive CD‐ROM for teens with cancer
Authors: Jones Judith K. , Kamani Sharmila A. , Bush Patricia J. , Hennessy Karen A. , Marfatia Aditya , Shad Aziza T. 
Published: June 2010

AbstractBackgroundCancer is the number one disease killer of children and adolescents in North America. For adolescents, this diagnosis comes at a particularly vulnerable stage. Educating adolescents with cancer from diagnosis through treatment teaches and empowers them. Increasing evidence shows that these adolescents want more information. Few educational tools exist for young cancer patients; none are interactive; therefore, a CD‐ROM was developed to meet this need.ProcedureAnimation, voiceover, music, videos, and games were combined to develop a comprehensive multimedia CD‐ROM to teach 12‐ to 18‐year‐olds with solid tumors about their disease, treatment, coping skills, and late effects in an interactive and non‐threatening way. The CD‐ROM was evaluated in a pre–post design with 65 subjects recruited from four pediatric oncology centers randomized to the CD‐ROM or a “Handbook” containing analogous information. Pre–post questionnaires measured coping strategies, health locus of control, quality of life, cancer knowledge, and self‐efficacy; post‐test variables also included acceptability and use by teens, their families, and healthcare professionals.ResultsTeens receiving the CD‐ROM were significantly more likely to increase their internal locus of control scores; however, no significant differences were observed on other measures, attributable in part to the study sample size. Among teens, acceptability was higher in the CD‐ROM versus the Handbook group, but not different between the two parent groups. Pediatric oncology healthcare providers gave positive feedback on the CD‐ROM.ConclusionsThis CD‐ROM is an innovative and engaging educational tool—the first portable interactive product with access on demand for adolescents with solid tumors. Pediatr Blood Cancer. 2010;55:512–519. © 2010 Wiley‐Liss, Inc.