bluuebunny/crossref_metadata_2025 huggingface dataset:
Crosslink Effect and Albumin Adsorption onto Chitosan/Alginate Multilayered Systems: An in situ QCM‐D Study
Authors: Martins Gabriela V. , Merino Esther G. , Mano João F. , Alves Natália M.
Published: October 2010

The adsorption of HSA onto CHI/ALG multilayer assemblies was assessed in situ using QCM‐D. It was found that the behavior of HSA on biomaterials surface can be tuned by adjusting parameters of the polyelectrolyte system such as pH, layer number, crosslinker and polymer terminal layer. Our results confirmed the key role of electrostatic interactions during HSA adsorption, since oppositely charged surfaces were more effective in promoting protein adhesion. QCM‐D data revealed that crosslinking (CHI/ALG)5CHI films allows HSA to become adsorbed in physiological conditions. Our results suggested that the biological potential of biopolymers and the mild conditions of the LbL technique turn these natural nanoassemblies into a suitable choice to be used as pH‐sensitive coatings.

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Influence of substrate composition on the formation of phytic acid conversion coatings
Authors: Cui X. , Jin G. , Liu E. , Ding M. , Li Q. , Wang F.
Published: October 2010

In this paper, the formation and corrosion resistance of the phytic acid conversion coatings on Mg, Al, and AZ91D magnesium alloy were contrastively investigated using scanning electronic microscopy (SEM), Auger electron spectroscopy (AES), Fourier transform infrared spectroscopy (FTIR), electronic probe microscopic analyzer (EPMA), electronic balance, and electrochemical methods. The influence of phytic acid conversion coating as a middle layer on the properties of the paint on magnesium alloys was also investigated.

The results show that the formation process of the conversion coatings is evidently influenced by the compositions of the substrate. The coating on pure aluminum is thinner and compacter than that on pure magnesium and the coating formed on α phase in AZ91D magnesium alloy is thinner but denser than that on β phase. The phytic acid conversion coatings formed on Mg, Al, and AZ91D magnesium alloy can all increase their corrosion resistance. The active functional groups of hydroxyl and phosphate radical are rich in the conversion coatings, which can improve the bonding between the organic paint and magnesium alloy and then improve their corrosion resistance.
Analysis of the relation between water and resistivity isotherms in concrete
Authors: Andrade M. C. , Bolzoni F. , Fullea J.
Published: October 2010

Concrete is a porous material, that contains an alkaline solution, whose pore network enables mass transport from the exterior. The concrete as composite material is quasi an insulator when it is dry and presents relatively low resistivities, in the order of few kΩ cm when it is fully saturated. Concrete resistivity reflects the degree of saturation and is therefore a useful indicator of the risk of chemical attack and of reinforcement corrosion. The dependence of resistivity on the degree of saturation has been studied, yet this subject has still not been fully elucidated. The present paper studies the evolution of concrete drying from the end of curing in order to analyze the water and resistivity isotherms. Four concrete mixes (w/c = 0.4 and 0.7 after 3 and 7 days of curing wrapped in plastic sheets) have been prepared and submitted to conditions of isothermic water desorption in controlled atmospheres with relative humidity (RH) of 55, 65, 75, 85, 95%. Resistivity measurements were simultaneously carried out which enabled to identify for the four mixes the water content and the RH which gives resistivity values higher than 105 Ω cm. The radii of water‐filled pores calculated from Kelvin's law were found to be smaller than those calculated by integrating the mercury intrusion porosimetry (MIP) accumulated intrusion curve with the water lost during conditioning at different RHs. The water content measurement that seems to be most adequate for comparison with resistivity values is the volumetric fraction.
Study on hot corrosion behavior of Yb2Zr2O7 ceramic against Na2SO4 + V2O5 molten salts at temperatures of 900–1200 °C in air
Authors: Li S. , Liu Z.‐G. , Ouyang J.‐H.
Published: October 2010

Yb2Zr2O7 ceramic powders synthesized by chemical‐coprecipitation and calcination method were pressureless‐sintered at 1700 °C for 10 h in air to fabricate dense bulk materials. Hot corrosion studies were performed on Yb2Zr2O7 against Na2SO4 and Na2SO4 + V2O5 (molar ratio = 1:1) molten salts in a temperature range of 900–1200 °C for 8 h in air, respectively. Chemical reactions were investigated using X‐ray diffraction (XRD) and scanning electron microscopy (SEM). The Yb2Zr2O7 ceramic was severely corroded by Na2SO4 + V2O5 molten salt, however, no chemical reaction was found between individual Na2SO4 and Yb2Zr2O7. Yb2Zr2O7 reacted with Na2SO4 + V2O5 molten salt to form YbVO4 and m‐ZrO2. The thickness of hot corrosion scales formed at different temperatures was investigated to evaluate hot corrosion behavior based on fluxing mechanism. The introduction of vanadium into sulfate led to subsequent formation of NaVO3, which was acidic enough to dissolve Yb2Zr2O7 by acidic fluxing.
Corrosion inhibition of austenitic stainless steel by some pyrimidine compounds in hydrochloric acid
Authors: Caliskan N. , Akbas E.
Published: October 2010

The inhibition effect of two pyrimidine derivatives on the corrosion of austenitic stainless steel in 1 M HCl has been studied by Tafel plot, linear polarization, and electrochemical impedance spectroscopy (EIS) at 298 K. Results showed that compounds inhibited steel corrosion in a 1 M HCl solution and inhibition efficiencies increased with the concentration of inhibitor. Polarization curves indicated that all studied pyrimidine derivatives act as mixed type (cathodic/anodic) inhibitors. The adsorption of the inhibitors on the stainless steel surface was found to obey the Langmuir and Dubinin–Radushkevich adsorption isotherm models. Negative values of ΔGads in the acidic media ensured the spontaneity of the adsorption process.
Measuring the corrosion rate of steel in concrete – effect of measurement technique, polarisation time and current
Authors: Nygaard P. V. , Geiker M. R.
Published: October 2010

Both on‐site investigations and laboratory studies have shown that different corrosion rates are obtained when different commercially available corrosion rate instruments are used. The different electrochemical techniques and the measurement parameters used, i.e. polarisation current and time, are in some studies considered the main reasons for the variations. This paper presents an experimental study on the quantitative effect of polarisation time and current on the measured polarisation resistance – and thus the corrosion current density – of passively and actively corroding steel. Two electrochemical techniques often used in instruments for on‐site corrosion rate measurements are investigated. On passively corroding reinforcement the measured polarisation resistance was for both techniques found to be highly affected by the polarisation time and current and no plateaus at either short or long polarisation times, or low or high polarisation currents were identified. On actively corroding reinforcement a large effect of the polarisation time was also found, but only a minor effect of the polarisation current. The effect of the polarisation time was, however, practically independent of the corrosion rate for actively corroding steel. For both techniques guidelines for polarisation times and currents are given for (on‐site) non‐destructive corrosion rate measurements on reinforcement steel in concrete.
The effect of tannins and pH on the corrosion of steel in wood extracts
Authors: Zelinka S. L. , Stone D. S.
Published: October 2010

Tannins and pH are often cited as factors that affect the corrosiveness of wood yet there are few data to confirm these statements. The purpose of this paper is to systematically investigate the effect of tannins and pH on corrosion of metals in wood. Four wood species known to vary in both their pH and extractives were chosen and extracted with water. The pH, tannin content, and corrosion rate of carbon steel were determined for each extract. To test if pH and tannin were the only factors influencing corrosion, “synthetic” extracts were made by adding tannins to distilled water and adjusting the pH. At a given pH, increasing the tannin content inhibited corrosion and at a given level of tannin content, lowering the pH increased corrosion. An isocorrosion map as a function of pH and tannins was developed by using simple kinetic models to extrapolate the data. The data may be useful in estimating the relative corrosiveness of new, nonmetallic wood preservatives based upon the chemistry of naturally durable wood species.
Superheater fireside corrosion mechanisms in MSWI plants: Lab‐scale study and on‐site results
Authors: Brossard J.M. , Diop I. , Chaucherie X. , Nicol F. , Rapin C. , Vilasi M.
Published: October 2010

Combustion of municipal waste generates highly corrosive gases (HCl, SO2, NaCl, KCl, and heavy metals chlorides) and ashes containing alkaline chlorides and sulfates. Currently, corrosion phenomena are particularly observed on superheater's tubes. Corrosion rates depend mainly on installation design, operating conditions i.e., gas and steam temperature and velocity of the flue gas containing ashes. This paper presents the results obtained using an innovative laboratory‐scale corrosion unit, which simulates MSWI boilers conditions characterized by a temperature gradient at the metal tube in the presence of corrosive gases and ashes. The presented corrosion tests were realized on carbon steel at fixed metal temperature (400 °C). The influence of the flue gas temperature, synthetic ashes composition, and flue gas flow pattern were investigated. After corrosion test, cross sections of tube samples were characterized to evaluate thickness loss and estimate corrosion rate while the elements present in corrosion layers were analyzed.

Corrosion tests were carried out twice in order to validate the accuracy and reproducibility of results. First results highlight the key role of molten phase related to the ash composition and flue gas temperature as well as the deposit morphology, related to the flue gas flow pattern, on the mechanisms and corrosion rates.
High‐temperature oxidation resistance of Al2O3‐forming heat‐resisting alloys with noble metal and rare earth additions
Authors: Amano T.
Published: October 2010

High‐temperature oxidation behavior of Al2O3‐forming heat‐resisting alloys with noble metal (palladium, platinum, gold) and rare earth (yttrium) additions was studied in oxidizing atmospheres (oxygen, oxygen‐water vapor) for 18 ks at 1473, 1573, and 1673 K, by mass gain measurements, amount of spalled oxide, observation of surface appearance, X‐ray diffraction (XRD), scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and transmission electron microscopy (TEM). Mass gains of all the Al2O3‐forming Fe‐20Cr‐4Al alloys increased with increasing oxidation temperatures in both oxidation conditions. After oxidation in oxygen, the mass gains of the alloys with noble metal were almost the same values after any oxidation temperature. The mass gain of the alloys with yttrium decreased with increase in yttrium addition up to 0.1 mass%, and then tended to increase with 0.5 mass% yttrium addition at all oxidation temperatures studied. The amount of spalled oxide from the Fe‐20Cr‐4Al (A4) alloy showed the biggest value at 1573 K‐oxidation, and then decreased in the order of 1473 K, 1673 K. On the other hand, the amount of spalled oxide from the other alloys decreased compared with the A4 alloy. No spalled oxide from 0.5Pt, 0.05Y, and 0.5Y alloys was observed at any oxidation temperature. After oxidation in an oxygen‐water vapor mixture (dew point: 353 K), the mass gain of all the alloys showed similar values to that obtained in oxygen after any oxidation temperature. The amount of spalled oxide from the A4 alloy was about the same after oxidation at 1473 and 1573 K in oxygen, but then was higher when oxidized at 1673 K. The amount of spalled oxide from the other alloys obtained in oxygen–water vapor increased compared with those obtained in oxygen. On the other hand, the amount of spalled oxide from the 0.5Y alloy was zero after any oxidation temperature, and that from the 0.5Pt alloy was also zero after 1673 K‐oxidation.
Spectroelectrochemical and Photovoltaic Characterization of a Solution‐Processable n‐and‐p Type Dopable Pyrrole‐Bearing Conjugated Polymer
Authors: Baran Derya , Balan Abidin , Esteban Beatriz‐Meana , Neugebauer Helmut , Sariciftci Niyazi Serdar , Toppare Levent
Published: October 2010

D‐A‐D‐type polymers are of high interest in the field of photovoltaics and electrochromism. In this study we report the synthesis and electrochemical properties of PPyBT along with its photophysical properties and photovoltaic performance. PPyBT is soluble in common organic solvents and both n‐ and p‐type dopable, which is a desired property for conjugated polymers. During electrochemistry studies, the onset potentials of the polymer were determined as +0.2 V for oxidation and −1.4 V for reduction. Using these values, HOMO and LUMO energy levels were calculated. The photovoltaic properties of PPyBT were also studied. PL studies showed that there is a charge transfer between PPyBT (donor) and PCBM (acceptor).

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Photoinitiator‐Free UV‐Cured Acrylic Coatings Containing Magnetite Nanoparticles
Authors: Sangermano Marco , Vescovo Lorenzo , Pepino Niccolò , Chiolerio Alessandro , Allia Paolo , Tiberto Paola , Coisson Marco , Suber Lorenza , Marchegiani Giada
Published: October 2010

A dispersion of magnetite nanoparticles in hexane has been added to 1,6‐hexanediol diacrylate at 5–40 phr. The obtained formulations have been polymerized by means of UV light in the absence of any radical photoinitiator and the cured films have been fully characterized. The photoinitiator activity of the magnetite nanoparticles is demonstrated: upon photoexcitation, Fe3O4 can generate radicals which in turn start polymerization chains. Isothermal magnetization curves showed that at room temperature, the cured material exhibits no hysteretic features, indicating a superparamagnetic‐like behavior. At temperatures below 100 K, a significant magnetic hysteresis gradually appears but a substantial fraction of magnetic nanoparticles is still in the superparamagnetic phase even at T = 10 K.

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Plant organelle proteomics: Collaborating for optimal cell function
Authors: Agrawal Ganesh Kumar , Bourguignon Jacques , Rolland Norbert , Ephritikhine Geneviève , Ferro Myriam , Jaquinod Michel , Alexiou Konstantinos G. , Chardot Thierry , Chakraborty Niranjan , Jolivet Pascale , Doonan John H. , Rakwal Randeep
Published: October 2010

Organelle proteomics describes the study of proteins present in organelle at a particular instance during the whole period of their life cycle in a cell. Organelles are specialized membrane bound structures within a cell that function by interacting with cytosolic and luminal soluble proteins making the protein composition of each organelle dynamic. Depending on organism, the total number of organelles within a cell varies, indicating their evolution with respect to protein number and function. For example, one of the striking differences between plant and animal cells is the plastids in plants. Organelles have their own proteins, and few organelles like mitochondria and chloroplast have their own genome to synthesize proteins for specific function and also require nuclear‐encoded proteins. Enormous work has been performed on animal organelle proteomics. However, plant organelle proteomics has seen limited work mainly due to: (i) inter‐plant and inter‐tissue complexity, (ii) difficulties in isolation of subcellular compartments, and (iii) their enrichment and purity. Despite these concerns, the field of organelle proteomics is growing in plants, such as Arabidopsis, rice and maize. The available data are beginning to help better understand organelles and their distinct and/or overlapping functions in different plant tissues, organs or cell types, and more importantly, how protein components of organelles behave during development and with surrounding environments. Studies on organelles have provided a few good reviews, but none of them are comprehensive. Here, we present a comprehensive review on plant organelle proteomics starting from the significance of organelle in cells, to organelle isolation, to protein identification and to biology and beyond. To put together such a systematic, in‐depth review and to translate acquired knowledge in a proper and adequate form, we join minds to provide discussion and viewpoints on the collaborative nature of organelles in cell, their proper function and evolution. © 2010 Wiley Periodicals, Inc., Mass Spec Rev 30:772–853, 2011
The effects of dietary fish oil on inflammation, fibrosis and oxidative stress associated with obstructive renal injury in rats
Authors: Peake Jonathan M. , Gobe Glenda C. , Fassett Robert G. , Coombes Jeff S.
Published: October 2010

Scope: We examined whether dietary supplementation with fish oil modulates inflammation, fibrosis and oxidative stress following obstructive renal injury.

Methods and results: Three groups of Sprague–Dawley rats (n=16 per group) were fed for 4 wk on normal rat chow (oleic acid), chow containing fish oil (33 g eicosapentaenoic acid and 26 g docosahexaenoic acid per kg diet), or chow containing safflower oil (60 g linoleic acid per kg diet). All diets contained 7% fat. After 4 wk, the rats were further subdivided into four smaller groups (n=4 per group). Unilateral ureteral obstruction was induced in three groups (for 4, 7 and 14 days). The fourth group for each diet did not undergo surgery, and was sacrificed as controls at 14 days. When rats were sacrificed, plasma and portions of the kidneys were removed and frozen; other portions of kidney tissue were fixed and prepared for histology. Compared with normal chow and safflower oil, fish oil attenuated collagen deposition, macrophage infiltration, TGF‐β expression, apoptosis, and tissue levels of arachidonic acid, MIP‐1α, IL‐1β, MCP‐1 and leukotriene B4. Compared with normal chow, fish oil increased the expression of HO‐1 protein in kidney tissue.

Conclusions: Fish oil intake reduced inflammation, fibrosis and oxidative stress following obstructive renal injury.
Tea polyphenol (−)‐epigallocatechin‐3‐gallate inhibits nicotine‐ and estrogen‐induced α9‐nicotinic acetylcholine receptor upregulation in human breast cancer cells
Authors: Tu Shih‐Hsin , Ku Chung‐Yu , Ho Chi‐Tang , Chen Ching‐Shyang , Huang Ching‐Shui , Lee Chia‐Hwa , Chen Li‐Ching , Pan Min‐Hsiung , Chang Hui‐Wen , Chang Chien‐Hsi , Chang Yu‐Jia , Wei Po‐Li , Wu Chih‐Hsiung , Ho Yuan‐Soon
Published: October 2010

Scope: The aim of this research was to explore whether the tea‐polyphenol (–)‐epigallocatechin‐3‐gallate (EGCG) could be used as a potential agent for blocking smoking (nicotine, Nic)‐ or hormone (estradiol, E2)‐induced breast cancer cell proliferation through inhibition of a common signaling pathway.

Methods and results: To explore whether Nic (>0.1 μM, 24 h) and E2 (>1 nM, 24 h) significantly increased α9‐nicotinic acetylcholine (α9‐nicotinic acetylcholine receptor (nAChR)) mRNA and protein expression levels, real‐time PCR and immunoblotting analysis experiments were performed in human breast cancer (MCF‐7) cells. Luciferase promoter activity experiment was performed to test the α9‐nAChR promoter activity affected by Nic, E2 or EGCG. The results indicate that treatment with EGCG (1 μM) profoundly decreases Nic‐ and E2‐induced MCF‐7 proliferation by down regulating α9‐nAChR expression. The α9‐nAChR promoter activity is significantly induced by 24‐h treatment with Nic (10 μM) or E2 (10 nM) (>1.8 and ∼2.3‐fold, respectively) in MCF‐7 cells. Pretreatment with EGCG eliminated the Nic‐ and E2‐induced α9‐nAChR promoter‐dependent luciferase activity. We further demonstrate that combined treatment with EGCG profoundly inhibits [3H]‐Nic/ α9‐nAChR binding activity in breast cancer cells.

Conclusions: We found that the EGCG could be used as an agent for blocking smoking (Nic)‐ or hormone (E2)‐induced breast cancer cell proliferation by inhibiting of α9‐nAChR signaling pathway. This study reveals the novel antitumor mechanisms of EGCG, and these results may have significant applications for chemopreventive purposes in human breast cancer.
Anthocyanin‐derived phenolic acids form glucuronides following simulated gastrointestinal digestion and microsomal glucuronidation
Authors: Woodward Gary M. , Needs Paul W. , Kay Colin D.
Published: October 2010

Scope: Current research indicates that anthocyanins are primarily degraded to form phenolic acid products. However, no studies have yet demonstrated the metabolic conjugation of these anthocyanin‐derived phenolic acids in humans.

Methods and results: Within the present study, a simulated gastrointestinal digestion model was used to evaluate the potential degradation of anthocyanins post‐consumption. Subsequently, cyanidin (Cy) and pelargonidin and their degradation products, protocatechuic acid and 4‐hydroxybenzoic acid, were incubated in the presence of human liver microsomes to assess their potential to form hepatic glucuronide conjugates. For structural conformation, phenolic glucuronides were chemically synthesised and compared to the microsomal metabolites. During the simulated gastric digestion, anthocyanin glycosides (200 μM) remained stable however their aglycone derivatives were significantly degraded (20% loss), while during subsequent pancreatic/intestinal digestion only pelargonidin‐3‐glucoside remained stable while cyanidin‐3‐glucoside (30% loss) and Cy and pelagonidin aglycones were significantly degraded (100% loss, respectively). Following microsomal metabolism, pelargonidin formed 4‐hydroxybenzoic acid, which was further metabolised (65%) to form two additional glucuronide conjugates, while Cy formed protocatechuic acid, which was further metabolised (43%) to form three glucuronide conjugates.

Conclusions: We propose that following ingestion, anthocyanins may be found in the systemic circulation as free or conjugated phenolic acids, which should be a focus of future dietary interventions.
Determination of the conformations and relative configurations of exocyclic amines
Authors: Montalvo‐González J. Ascención , Iniestra‐Galindo María Guadalupe , Ariza‐Castolo Armando
Published: October 2010

The conformations and relative configurations of 20 amines, classified according to the following labeling scheme, were analyzed. Series a comprised compounds derived from N‐(1‐phenylethyl)cyclohexanamine, b comprised derivatives of N‐[1‐(naphthalen‐2‐yl)ethyl]cyclohexanamine, c comprised derivatives of N‐(diphenylmethyl)cyclohexanamine, and d comprised derivatives of N‐(propan‐2‐yl)cyclohexanamine. The compounds were labeled as follows: 1 indicates cyclohexanamine, 2 indicates 2‐methylcyclohexanamines, 3 indicates 3‐methylcyclohexanamines, 4 indicates 4‐methylcyclohexanamines, and 5 indicates 4‐tert‐butylcyclohexanamines. These compounds were prepared without the use of stereoselective induction and, therefore, all expected stereoisomers were observed. Structural assignments were established by 1H, 13C, and 15N NMR. Copyright © 2010 John Wiley & Sons, Ltd.
Lateral diffusion in sphingomyelin bilayers
Authors: Filippov A. V. , Rudakova M. A. , Munavirov B. V.
Published: October 2010

Sphingomyelin (SM) is an important lipid of eukaryotic cellular membranes and neuronal tissues. We studied lateral diffusion in macroscopically oriented bilayers of synthetic palmitoylsphingomyelin (PSM) and natural sphingomyelins of egg yolk (eSM), bovine brain (bSM) and bovine milk (mSM) by pulsed field gradient NMR (PFG NMR) in the temperature range 45–60 °C. We found that the mean values of lateral diffusion coefficients (LDCs) of SMs are 1.9‐fold lower compared with those of dipalmitoylphosphatidylcholine (DPPC), which is similar in molecular structure. This discrepancy could be explained by the characteristics of intermolecular SM interactions. The LDCs of different SMs differ: egg SM is most similar to PSM; both of them have a 10% higher LDC value compared with the other two natural SMs. Besides, all natural SMs show a complicated form of the spin‐echo diffusion decay (DD), which is an indicator of a distribution of LDC values in bilayers. This peculiarity is explained by the broad distributions of hydrocarbon chain lengths of the natural SMs studied here, especially mSM and bSM. We confirmed the relationship between chain length and LDC in the bilayers by computer analysis of a set of 1H NMR spectra obtained by scanning the value of the pulsed field gradient. There is a correlation between lower LDC values and SM molecules with longer acyl chains. The most probable mechanisms by which long‐chain SM molecules decrease their lateral diffusion relative to the average value are protrusion into the other side of the bilayer or lateral separation into areas that diverge with their LDCs. Copyright © 2010 John Wiley & Sons, Ltd.
Prior estimate‐based compressed sensing in parallel MRI
Authors: Wu Bing , Millane Rick P. , Watts Richard , Bones Philip J.
Published: October 2010

Two improved compressed sensing (CS)‐based image reconstruction methods for MRI are proposed: prior estimate‐based compressed sensing (PECS) and sensitivity encoding‐based compressed sensing (SENSECS). PECS allows prior knowledge of the underlying image to be intrinsically incorporated in the image recovery process, extending the use of data sorting as first proposed by Adluru and DiBella (Int J Biomed Imaging 2008: 341648). It does so by rearranging the elements in the underlying image based on the magnitude information gathered from a prior image estimate, so that the underlying image can be recovered in a new form that exhibits a higher level of sparsity. SENSECS is an application of PECS in parallel imaging. In SENSECS, image reconstruction is carried out in two stages: SENSE and PECS, with the SENSE reconstruction being used as a image prior estimate in the following PECS reconstruction. SENSECS bypasses the conflict of sampling pattern design in directly applying CS recovery in multicoil data sets and exploits the complementary characteristics of SENSE‐type and CS‐type reconstructions, hence achieving better image reconstructions than using SENSE or CS alone. The characteristics of PECS and SENSECS are investigated using experimental data. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
The 6‐minute walk test in Duchenne/Becker muscular dystrophy: Longitudinal observations
Authors: MCDonald Craig M. , Henricson Erik K. , Han Jay J. , Abresch R. Ted , Nicorici Alina , Atkinson Leone , Elfring Gary L. , Reha Allen , Miller Langdon L.
Published: October 2010

In this study we used the 6‐minute walk distance (6MWD) to characterize ambulation over time in Duchenne/Becker muscular dystrophy (DBMD). The 6MWD was assessed in 18 boys with DBMD and 22 healthy boys, ages 4–12 years, over mean [range] intervals of 58 [39–87] and 69 [52–113] weeks, respectively. Height and weight increased similarly in both groups. At 52 weeks, 6MWD decreased in 12 of 18 (67%) DBMD subjects (overall mean [range]: 357 [125–481] to 300 [0–510] meters; Δ −57 meters, −15.9%), but increased in 14 of 22 (64%) healthy subjects (overall mean [range]: 623 [479–754] to 636 [547–717] meters; Δ +13 meters, +2.1%). Two DBMD subjects lost ambulation. Changes in 6MWD depended on stride length and age; improvements usually occurred by 7–8 years of age; older DBMD subjects worsened, whereas older healthy subjects were stable. The 6MWD changes at 1 year confirm the validity of this endpoint and emphasize that preserving ambulation must remain a major goal of DBMD therapy. Muscle Nerve, 2010
Supply chain coordination with shelf‐space and retail price dependent demand and heterogeneous retailers
Authors: Luo Xiaoning , Jiang Yanmin , Hu Qiying
Published: October 2010

We consider supply chain coordination in which a manufacturer supplies some product to multiple heterogeneous retailers and wishes to coordinate the supply chain via wholesale price and holding cost subsidy. The retail price is either exogenous or endogenous. The market demand is described by the market share attraction model based on all retailers'shelf‐spaces and retail prices. We obtain optimal solutions for the centralized supply chain, where the optimal retail pricing is a modified version of the well‐known cost plus pricing strategy. We further get feasible contracts for the manufacturer to coordinate the hybrid and decentralized supply chains. The manufacturer can allocate the total profit free to himself and the retail market via the wholesale price when the retail price is exogenous, but otherwise he cannot. Finally, we point out that different characteristics of the retail market are due to different powers of the manufacturer, and the more power the manufacturer has, the simpler the contract to coordinate the chain will be. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010
Potential impact of recharging plug‐in hybrid electric vehicles on locational marginal prices
Authors: Wang Lizhi , Lin Anhua , Chen Yihsu
Published: October 2010

Plug‐in hybrid electric vehicles (PHEVs), upon market penetration, will create additional recharging loads to the electric power systems. This article considers different recharging scenarios and uses game theoretic models to study the potential impact of the recharging loads on locational marginal prices (wholesale electricity prices). Computational results from a Pennsylvania‐New Jersey‐Maryland Interconnection case study show that, under the existing recharging infrastructures, even a small magnitude of load increase caused by PHEV recharging could have a significant undesirable impact on locational marginal prices. The impact could be mitigated to a varying extent by the availability of possible future recharging infrastructures, including realtime pricing recharging meters, battery stations, or vehicle‐to‐grid technology.© 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010
Route optimization for multiple searchers
Authors: Royset Johannes O. , Sato Hiroyuki
Published: October 2010

We consider a discrete time‐and‐space route‐optimization problem across a finite time horizon in which multiple searchers seek to detect one or more probabilistically moving targets. This article formulates a novel convex mixed‐integer nonlinear program for this problem that generalizes earlier models to situations with multiple targets, searcher deconfliction, and target‐ and location‐dependent search effectiveness. We present two solution approaches, one based on the cutting‐plane method and the other on linearization. These approaches result in the first practical exact algorithms for solving this important problem, which arises broadly in military, rescue, law enforcement, and border patrol operations. The cutting‐plane approach solves many realistically sized problem instances in a few minutes, while existing branch‐and‐bound algorithms fail. A specialized cut improves solution time by 50[percnt] in difficult problem instances. The approach based on linearization, which is applicable in important special cases, may further reduce solution time with one or two orders of magnitude. The solution time for the cutting‐plane approach tends to remain constant as the number of searchers grows. In part, then, we overcome the difficulty that earlier solution methods have with many searchers. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010
A robust preconditioning technique for the extended finite element method
Authors: Menk Alexander , Bordas Stéphane P. A.
Published: October 2010

The extended finite element method enhances the approximation properties of the finite element space by using additional enrichment functions. But the resulting stiffness matrices can become ill‐conditioned. In that case iterative solvers need a large number of iterations to obtain an acceptable solution. In this paper a procedure is described to obtain stiffness matrices whose condition number is close to the one of the finite element matrices without any enrichments. A domain decomposition is employed and the algorithm is very well suited for parallel computations. The method was tested in numerical experiments to show its effectiveness. The experiments have been conducted for structures containing cracks and material interfaces. We show that the corresponding enrichments can result in arbitrarily ill‐conditioned matrices. The method proposed here, however, provides well‐conditioned matrices and can be applied to any sort of enrichment. The complexity of this approach and its relation to the domain decomposition is discussed. Computation times have been measured for a structure containing multiple cracks. For this structure the computation times could be decreased by a factor of 2. Copyright © 2010 John Wiley & Sons, Ltd.
Implicit Large Eddy Simulation of transition to turbulence at low Reynolds numbers using a Discontinuous Galerkin method
Authors: Uranga A. , Persson P.‐O. , Drela M. , Peraire J.
Published: October 2010

The present work predicts the formation of laminar separation bubbles at low Reynolds numbers and the related transition to turbulence by means of Implicit Large Eddy Simulations with a high‐order Discontinuous Galerkin method. The flow around an SD7003 infinite wing at an angle of attack of 4° is considered at Reynolds numbers of 10 000, 22 000, and 60 000 in order to gain insight into the characteristics of the laminar and turbulent regimes. At the lowest Reynolds number studied, the flow remains laminar and two dimensional over the wing surface, with a periodic vortex shedding. For higher Reynolds numbers, the flow is unsteady over the upper wing surface and exhibits a separation bubble along which the flow transitions to turbulence. Tollmien–Schlichting (TS) waves are observed in the boundary layer, and transition is found to be caused by unstable TS modes as revealed by the growth of the stream‐wise amplification factor. Copyright © 2010 John Wiley & Sons, Ltd.
A conservative high‐order discontinuous Galerkin method for the shallow water equations with arbitrary topography
Authors: Kesserwani Georges , Liang Qiuhua
Published: October 2010

A conservative high‐order Godunov‐type scheme is presented for solving the balance laws of the 1D shallow water equations (SWE). The scheme adopts a finite element Runge–Kutta (RK) discontinuous Galerkin (DG) framework. Based on an overall third‐order accurate formulation, the model is referred to as RKDG3. Treatment of topographic source term is built in the DG approximation. Simplified formulae for initializing bed data at a discrete level are derived by assuming a local linear bed function to ease practical flow simulations. Owing to the adverse effects caused by using an uncontrolled global limiting process in an RKDG3 scheme (RKDG3‐GL), a new conservative RKDG3 scheme with user‐parameter‐free local limiting method (RKDG3‐LL) is designed to gain better accuracy and conservativeness. The advantages of the new RKDG3‐LL model are demonstrated by applying to several steady and transient benchmark flow tests with irregular (either differentiable or non‐differentiable) topography. Copyright © 2010 John Wiley & Sons, Ltd.
3D corrected XFEM approach and extension to finite deformation theory
Authors: Loehnert S. , Mueller‐Hoeppe D. S. , Wriggers P.
Published: October 2010

In this paper, the modified or corrected extended finite element method originally presented in Fries (Int. J. Numer. Meth. Engng. 2008; 75:503–532) for the 2D case is extended to 3D including different remedies for the problem that the crack front enrichment functions are linearly dependent in the blending elements. In the context of this extension, we address a number of computational issues of the 3D XFEM, in particular possible quadrature rules for elements with discontinuities. Also, the influence of finite deformation theory for crack simulations in comparison to linear elastic fracture mechanics is investigated. A number of numerical examples demonstrate the behavior of the presented possibilities. Copyright © 2010 John Wiley & Sons, Ltd.
A non‐linear interface element for 3D mesoscale analysis of brick‐masonry structures
Authors: Macorini L. , Izzuddin B. A.
Published: October 2010

This paper presents a novel interface element for the geometric and material non‐linear analysis of unreinforced brick‐masonry structures. In the proposed modelling approach, the blocks are modelled using 3D continuum solid elements, whereas the mortar and brick–mortar interfaces are modelled by means of the 2D non‐linear interface element. This enables the representation of any 3D arrangement for brick‐masonry, accounting for the in‐plane stacking mode and the through‐thickness geometry, and importantly it allows the investigation of both the in‐plane and the out‐of‐plane responses of unreinforced masonry panels. A co‐rotational approach is employed for the interface element, which shifts the treatment of geometric non‐linearity to the level of discrete entities, and enables the consideration of material non‐linearity within a simplified local framework employing first‐order kinematics. In this respect, the internal interface forces are modelled by means of elasto‐plastic material laws based on work‐softening plasticity and employing multi‐surface plasticity concepts. Following the presentation of the interface element formulation details, several experimental–numerical comparisons are provided for the in‐plane and out‐of‐plane static behaviours of brick‐masonry panels. The favourable results achieved demonstrate the accuracy and the significant potential of using the developed interface element for the non‐linear analysis of brick‐masonry structures under extreme loading conditions. Copyright © 2010 John Wiley & Sons, Ltd.
Finite element implementation of a kinetic model of dynamic strain aging in aluminum–magnesium alloys
Authors: Zhang F. , Bower A. F. , Curtin W. A.
Published: October 2010

Soare and Curtin (Acta Mater. 2008; 56:4091–4101, 4046–4061) have recently developed a model of dynamic strain aging in solute‐strengthened alloys. Their constitutive law describes time‐dependent solute strengthening using rate equations that can be calibrated using atomistic simulations. In this paper, their material model is incorporated into a continuum finite element simulation, with a view to completing a multi‐scale method for predicting the formability of solute‐strengthened alloys. The Soare–Curtin model is first re‐formulated as a state‐variable constitutive law, which is suitable for finite element computations. An efficient numerical procedure is then developed to track the strength distribution of aging mobile and forest dislocations in the solid during deformation. The method is tested by simulating the behavior of a 3D aluminum–magnesium alloy tensile specimen subjected to uniaxial loading at constant nominal strain rate. The model predicts the influence of strain rate on the steady‐state flow stress of Al–Mg alloys, but no Portevin–Le Châtelier bands or serrated flow were observed in any of our simulations, and the influence of strain rate on tensile ductility is not predicted correctly. The reasons for this behavior and possible resolutions are discussed. Copyright © 2010 John Wiley & Sons, Ltd.
Isogeometric analysis of nearly incompressible solids
Authors: Taylor R. L.
Published: October 2010

This paper describes the use of isogeometric methods to solve problems in finite deformation solid mechanics in which compressible and nearly incompressible behavior may be encountered. The work is based on a three‐field variational structures in which displacements, mean stress and volume effects are independently approximated. Using this approach and tensor product NURBS approximations it is shown how the solution can be conducted in a standard approach, where main variables are organized at nodes (control points). This leads to an efficient procedure to solve large problems of a general form without the need to develop special solution strategies. The approach is demonstrated on some standard test problems. Copyright © 2010 John Wiley & Sons, Ltd.
An edge‐based smoothed finite element method (ES‐FEM) using 3‐node triangular elements for 3D non‐linear analysis of spatial membrane structures
Authors: Zhang Zhi‐Qian , Liu G. R.
Published: October 2010

An edge‐based smoothed finite element method using 3‐node triangular membrane elements (ES‐FEM‐T3) is proposed to analyze three‐dimensional (3D) spatial membrane structures under large deflection, rotation, and strain. In our 3D formulation, co‐rotational local coordinate systems associated with the edge‐based smoothing domains are constructed. Edge‐based gradient smoothing for the spatial membrane structure is performed in global Cartesian coordinate system and transformed into the co‐rotational local coordinate system. The smoothed strain and stress can then be properly evaluated in the co‐rotational local coordinate system after the elimination of the rigid body motions simply by coordinates transformation. Explicit time integration scheme is used to compute the transient response of the 3D spatial membrane structure to time‐domain excitations, and the dynamic relaxation method is employed to obtain steady‐state solutions. The numerical results demonstrate that the proposed method produces much better solution accuracy and computational efficiency than the standard FEM using T3 membrane element. Copyright © 2010 John Wiley & Sons, Ltd.
SGBEM–FEM coupling for analysis of cracks in 3D anisotropic media
Authors: Rungamornrat Jaroon , Mear Mark E.
Published: October 2010

A weakly singular symmetric Galerkin boundary element method (SGBEM) is coupled with the standard finite element method (FEM) in order to establish an accurate and efficient numerical technique for analysis of fractures in three‐dimensional, anisotropic, linearly elastic media. In the strategy, the weakly singular SGBEM developed by Rungamornrat and Mear (textitInt. J. Solids Struct. 2008; 45:1283–1301; Comput. Methods Appl. Mech. Engrg 2008; 197:4319–4332) is utilized to model a small‐scale region containing the crack while the (possibly large and complex) compliment region is treated by the FEM. The coupled technique exploits the positive features of both methods; the SGBEM proves to be a convenient and highly accurate method for obtaining mixed‐mode stress intensity factors along the crack front, whereas the FEM is very efficient for modeling large‐scale problems in the absence of cracks. An important aspect of the formulation and implementation of the technique is that continuity of displacement and traction across the interface between the SGBEM and FEM regions is enforced in a weak sense. This allows the two regions (one modeled by the SGBEM and the other by the FEM) to be discretized independently without the need for the resulting meshes to conform on the interface separating the regions, and this flexibility in the discretization process leads to a significant reduction in the modeling effort. To demonstrate the utility and accuracy of the technique, several boundary value problems involving both embedded and surface breaking cracks are treated, and it is shown that the coupled technique yields highly accurate stress intensity factors that exhibit only a slight dependence upon mesh refinement. Copyright © 2010 John Wiley & Sons, Ltd.
A partition of unity finite element method for simulating non‐linear debonding and matrix failure in thin fibre composites
Authors: Radtke F. K. F. , Simone A. , Sluys L. J.
Published: October 2010

We present a partition of unity finite element method for simulating non‐linear debonding and matrix failure in thin fibre composites. Fibres are superimposed on a background mesh without meshing them. The constitutive behaviour of the matrix material, the fibre material and the fibre–matrix bond can be independently defined. A concise derivation of the discrete governing equations is given for two classes of continuum damage models describing the matrix material. A non‐linear bond‐slip law including debonding and fibre pull‐out behaviour is used. Several examples illustrate the potential of the proposed approach. Copyright © 2010 John Wiley & Sons, Ltd.
An element‐free analysis of mechanical and thermal buckling of functionally graded conical shell panels
Authors: Zhao X. , Liew K. M.
Published: October 2010

This paper presents a mechanical and thermal buckling analysis of metal and ceramic functionally graded conical shell panels using the element‐free kp‐Ritz method. The formulation is based on the first‐order shear deformation shell theory, which accounts for the transverse shear strains and rotary inertia, and mesh‐free kernel particle functions are employed to approximate the two‐dimensional displacement fields. The effective material properties of the functionally graded conical shell panels are assumed to be smooth and continuous through their thickness direction, and are determined according to a power‐law distribution of the volume fractions of their constituents. Convergence studies are performed in terms of the number of nodes, and comparisons between the current solutions and those reported in the literature are provided to verify the accuracy of the proposed method. Three types of functionally graded conical shell panels, Al/ZrO2, SUS304/Si3N4, and Al2O3/Ti−6Al−4V are selected for study, and the effects of the volume fraction, boundary condition, semi‐vertex angle, length‐to‐thickness ratio, and temperature‐dependent material properties on the buckling strength are discussed in detail. Copyright © 2010 John Wiley & Sons, Ltd.
The myths of coping with loss in undergraduate psychiatric nursing books
Authors: Holman E. Alison , Perisho Jennifer , Edwards Ada , Mlakar Natalie
Published: October 2010

Nurses often help patients cope with loss. Recent research has cast doubt on the validity of early theories about loss and grief commonly taught to nurses. We systematically examined the accuracy of information on coping with loss presented in 23 commonly used undergraduate psychiatric nursing books. All 23 books contained at least one unsupported assumption (myth) about loss and grief. In 78% of these books, authors described four or more myths and only one evidence‐based finding about coping with loss. On balance most books provided details on the myths about grief and loss with minimal discussion of the current evidence. Authors of psychiatric nursing books continue to disseminate unsupported theories about grief responses without adequately acknowledging evidence challenging core assumptions underlying them. © 2010 Wiley Periodicals, Inc. Res Nurs Health 33:486–499, 2010
Predictors of use of hearing protection among a representative sample of farmers
Authors: McCullagh M.C. , Ronis D.L. , Lusk S.L.
Published: October 2010

Farmers experience higher rates of noise‐induced hearing loss (NIHL) than workers in most other industries. We developed a model of farmers' use of hearing protection, and tested it with a random sample (n = 532) of farmers from the upper Midwest. Barriers to using hearing protection (e.g., difficulty communicating; OR = .44, p < .003) were negatively related to use. Greater access/availability of hearing protectors (OR = 1.75, p < .010) and male gender (OR = .43, p < .019) were positively related to use. The model correctly predicted use of hearing protection for 74% of the cases. Overall, farmers demonstrated low hearing protector use, and results were similar to those from previous studies of non‐farm workers. Findings from this study will be useful in designing interventions to increase farmers' hearing protector use and decrease their rates of NIHL. © 2010 Wiley Periodicals, Inc. Res Nurs Health 33:528–538, 2010