bluuebunny/crossref_metadata_2025 huggingface dataset:
Fire behaviour of plastic parts in electrical appliances—standards versus required fire safety objectives
Authors: Babrauskas Vytenis , Simonson Margaret
Published: August 2006

For most categories of consumer electrical appliances, UL and IEC standards are typically the only widely used safety standards. A number of these standards are examined to determine if they incorporate technical provisions so that complying products would thereby meet expected fire safety objectives. Specifically, the provisions are examined governing plastic parts in electrical appliances. It is found that the standards do not consistently contain provisions that would, by themselves, suffice for a designer to produce a fire‐safe design. Instead, major shortcomings exist, and if an appliance were designed solely to meet the standards and without any additional fire safety considerations, it would not have a reasonable degree of safety. A typical outcome could be a product which is readily ignitable by a small external ignition source and which shows fierce burning upon being so ignited. Furthermore, an internal electrical fault in such a product would probably not be contained within the unit and, rather, would spread to its easily combustible exterior surfaces and produce a similar, fierce fire. It is urged that UL and IEC standards be upgraded so that compliance with the standards would carry a reasonable assurance that fire safety objectives have been met. The recommendations made are intended to cover all UL and IEC appliance standards, not limited to the example cases considered. Copyright © 2006 John Wiley & Sons, Ltd.
Morphology and alkaloidal profile of the seedlings of Erythrina americana MILL. and E. coralloides A.DC.
Authors: San Miguel‐Chávez R. , Soto‐Hernández M. , Terrazas T. , Kite G.
Published: August 2006

The morphological characteristics and the alkaloid content of seedlings of the closely related Erythrina americana and E. coralloides were studied in order to document new taxonomic evidence for the separation of these species. Seedlings of E. americana have a slim hypocotyl, opposed trifoliate juvenile leaves with entire margin and acuminated apex. The seedlings of E. coralloides are distinguished by a hypocotyl that becomes swollen, grooved and curved during growth, and opposed unilobate juvenile leaves with whole margin and mucronated apex. Moreover, leaves, hypocotyls and roots develop in a different manner in each species. The alkaloids erysosalvine, erythraline‐N‐oxide, erythrartine and 8‐oxo‐α‐erythroidine are present only in seedlings of E. americana, whilst erythraline and erysopine are exclusive to E. coralloides . It is reasoned that the morphological and chemical evidence revealed in this study supports the recognition of both taxa as independent species. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Seed morphology of Cuscuta L. (Convolvulaceae) in Egypt and its systematic significance
Authors: Abdel Khalik K. N.
Published: August 2006

The seed morphology of eight taxa of Cuscuta from Egypt has been studied using light and scanning electron microscopy, to determine the significance of seed coat features as taxonomic characters. Macro‐ and micromorphological characters, including seed shape, colour, size, epidermal cell shape, anticlinal boundaries, outer periclinal cell wall and relief of outer cell walls are presented. Three types of anticlinal cell wall boundaries are recognized and two different shapes of outer periclinal cell wall are described. The secondary sculpture of the cell wall varies from striate to micro‐reticulate, and smooth to fine folds. A key for the identification of the investigated taxa based on seed characters is provided. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Distributed and integrated response of a geographic information system‐based hydrologic model in the eastern Palouse region, Idaho
Authors: Brooks Erin S. , Boll Jan , McDaniel Paul A.
Published: August 2006

Verification of distributed hydrologic models is rare owing to the lack of spatially detailed field measurements and a common mismatch between the scale at which soil hydraulic properties are measured and the scale of a single modelling unit. In this study, two of the most commonly calibrated parameters, i.e. soil depth and the vertical distribution of lateral saturated hydraulic conductivity Ks, were eliminated by a spatially detailed soil characterization and results of a hillslope‐scale field experiment. The soil moisture routing (SMR) model, a geographic information system‐based hydrologic model, was modified to represent the dominant hydrologic processes for the Palouse region of northern Idaho. Modifications included Ks as a double exponential function of depth in a single soil layer, a snow accumulation and melt algorithm, and a simple relationship between storage and perched water depth (PWD) using the drainable porosity. The model was applied to a 2 ha catchment without calibration to measured data. Distributed responses were compared with observed PWD over a 3‐year period on a 10 m × 15 m grid. Integrated responses were compared with observed surface runoff at the catchment outlet. The modified SMR model simulated the PWD fluctuations remarkably well, especially considering the shallow soils in this catchment: a 0·20 m error in PWD is equivalent to only a 1·6% error in predicted soil moisture content. Simulations also captured PWD fluctuations during a year with high spatial variability of snow accumulation and snowmelt rates at upslope, mid‐slope, and toe slope positions with errors as low as 0·09 m, 0·12 m, and 0·12 m respectively. Errors in distributed and integrated model simulations were attributed mostly to misrepresentation of rain events and snowmelt timing problems. In one location in the catchment, simulated PWD was consistently greater than observed PWD, indicating a localized recharge zone, which was not identified by the soil morphological survey. Copyright © 2006 John Wiley & Sons, Ltd.
Assessing regional land‐use/cover influences on New Jersey Pinelands streamflow through hydrograph analysis
Authors: Dow Charles L.
Published: August 2006

Relative baseflow volume and streamflow flashiness indices were used to assess relationships between land use/cover and streamflow regime in nine New Jersey (NJ) Pinelands streams. Baseflow index (BFI) and Richards–Baker flashiness index (RBI) were estimated on an October–September water year, with period‐of‐record changes assessed by trend analysis and differences between watersheds assessed by examining index versus land‐use/cover relationships using a data period common to all study sites. Four streams, among the more urbanized watersheds of the nine study sites, were found to have significant (α = 0·05) trends in both indices. The two most urbanized study sites showed decreasing baseflow and increasing flashiness; however, the other two streams showed the opposite trends. An apparent slowdown in urbanization towards the second half of the streamflow period of record, along with potential changes in wetland agricultural practices in the latter two watersheds, may explain their trend results. A marginally significant (α = 0·10) decreasing relationship was found between mean annual BFI and wetland agriculture, whereas a significant (α = 0·05) increasing relationship was determined between mean annual RBI and artificial lakes/reservoirs. Principal component analysis showed an association between wetland agriculture and artificial lakes/reservoirs which suggested that both of the significant index versus land‐use/cover relationships reflect wetland agricultural activities. Because these significant relationships involved land uses/covers with small spatial extents (⩽5%), they demonstrated that land‐use practices can have a greater impact than spatial extent on stream hydrology. This study is the first step in assessing the effect on the NJ Pinelands stream ecology by streamflow alteration due to wetland agricultural activities. Copyright © 2006 John Wiley & Sons, Ltd.
Methyl‐CpG binding proteins are involved in restricting differentiation plasticity in neurons
Authors: Setoguchi Hiroki , Namihira Masakazu , Kohyama Jun , Asano Hirotsugu , Sanosaka Tsukasa , Nakashima Kinichi
Published: August 2006

Neurons and astrocytes are generated from common neural precursors, yet neurogenesis precedes astrocytogenesis, which normally commences at later stages of development. We have previously reported that a particular cytosine residue within a STAT3‐binding site in the astrocyte‐specific marker glial fibrillary acidic protein (GFAP) gene promoter becomes demethylated in neuroepithelial cells as gestation proceeds. This demethylation correlates tightly with the onset of astrocyte differentiation, suggesting that a change in DNA methylation at cell‐type‐specific gene promoters controls the switch from neurogenesis to astrocytogenesis in the developing brain. Here, we show that late‐gestation neuroepithelial cells, which have already lost the methylation in the STAT3‐binding site within the GFAP promoter, can still give rise to neurons and that these neurons do not respond to a STAT3‐activating cytokine to express GFAP. Members of a transcriptional repressor family, the methylated‐CpG binding proteins (MBDs), including MeCP2, are predominantly expressed in neurons, and ectopic MeCP2 expression inhibited astrocyte differentiation of neuroepithelial cells. Moreover, we found that exon 1 of the GFAP gene remains hypermethylated even in neuroepithelial cells at a late developmental stage and in neurons differentiated from such neuroepithelial cells. We further demonstrate that MeCP2 actually binds to the highly methylated exon 1 of the GFAP gene in neurons. These results suggest that region‐specific DNA methylation and MBDs play an important role in the regulation of differentiation plasticity in neurons. © 2006 Wiley‐Liss, Inc.
Gene expression and protein localization of calmodulin‐dependent phosphodiesterase in adult rat retina
Authors: Santone Rocco , Giorgi Mauro , Maccarone Rita , Basso Manuela , Deplano Stefania , Bisti Silvia
Published: August 2006

Calcium calmodulin‐dependent cyclic nucleotide phosphodiesterase (PDE1) was identified in crude extract and immunolabeled sections of rat retina. Both cAMP and cGMP PDE activities were stimulated by calcium‐calmodulin (4.7‐fold and 2.3‐fold, respectively). To characterize PDE1 isoforms in retinal cells further, we used antibodies that specifically recognize PDE1 gene products. PDE1B antibody stained a band at molecular mass of 63 kDa whereas PDE1C antibody recognized two bands at 74‐ and 70‐kDa molecular masses. Two PDE1A antibodies (against N‐terminal and C‐terminal peptides) detected a band at 79 kDa never described before. Immunohistochemical analysis showed a distribution of PDE1A in the outer retina with a bright fluorescence in the outer segments of photoreceptors. PDE1B is uniformly distributed across the retina. PDE1C is confined mainly to the inner retina, with a precise localization in the inner nuclear layer. Immunostaining with choline acetyltransferase antibody indicates localization in cholinergic amacrine cell. The present data provide evidence of expression of PDE1 isoforms in mammalian retina with a complementary distribution of PDE1A and PDE1C, suggesting different roles in retinal function. © 2006 Wiley‐Liss, Inc.
Phonon confinement studies in nanocrystalline anatase‐TiO2 thin films by micro Raman spectroscopy
Authors: Balaji S. , Djaoued Y. , Robichaud J.
Published: August 2006

Raman studies were performed on titania thin films prepared by polyethylene glycol (PEG) assisted, low‐temperature, sol–gel method. The Raman spectra of the films show a systematic blue shift in the peak position and a broadening in the full width at half‐maximum (FWHM) when compared with those of the bulk anatase TiO2 powder. Several reports have appeared indicating this kind of peak shift and broadening of FWHM, which were attributed to the confinement of phonons in the anatase nanocrystallites. In this paper, we report an analysis of quantum size effect in the Raman spectra of nanocrystalline TiO2 thin films performed by utilizing the phonon dispersion relation of the anatase phase which has been obtained from a work based on density functional perturbation theory (DFPT). For comparison purposes the quantum size effect calculations have also been done utilizing the dispersion relations of the rutile phase. There is good agreement between the crystallite sizes evaluated from the equally weighted Raman line intensity of the dispersion relations obtained from the DFPT and those determined by X‐ray diffraction. Copyright © 2006 John Wiley & Sons, Ltd.
Comparison of two capillary electrophoresis online stacking modes by analysis of polycyclic aromatic hydrocarbons in airborne particulates
Authors: Song Guan‐Qun , Peng Zhen‐Lei , Lin Jin‐Ming
Published: August 2006

Naphthalene, fluorene, pyrene, anthracene, phenanthrene, and chrysene were successfully separated by CD‐modified MEKC (CD‐MEKC) using 20 mM borate (pH 9.0) containing 90 mM SDS and 75 mM β‐CD. Two online stacking methods, i. e., sweeping and field‐enhanced sample injection (FESI), were explored to enhance the detection sensitivity. The influences of some crucial parameters in sweeping and FESI procedures were investigated. For FESI method, a plug of water and low‐conductivity sample matrix was used to increase the stacking efficiency. Compared with the sweeping method, FESI can increase the sensitivity in the range of 10–20‐fold. The proposed method was used for the analysis of polycyclic aromatic hydrocarbons in airborne particulates.
Comparative enantioseparation of seven triazole fungicides on (S,S)‐Whelk O1 and four different cellulose derivative columns
Authors: Pan Chun‐Xiu , Shen Bao‐Chun , Xu Bei‐jia , Chen Juan‐Juan , Xu Xiu‐Zhu
Published: August 2006

The comparative enantioseparation of seven chiral triazole fungicides on a Pirkle type (S,S)‐Whelk O1 chiral column and four different cellulose derivative columns, namely cellulose tribenzoate (CTB), cellulose tris(4‐methylbenzoate) (CTMB), cellulose triphenylcarbamate (CTPC), and cellulose tris(3,5‐dimethylphenyl carbamate) (CDMPC), in normal phase mode is described. The seven triazole fungicides investigated were tebuconazole, hexaconazole, myclobutanil, diniconazole, uniconazole, paclobutrazol, and triadimenol. The chiral separation of each solute was investigated with ethanol, n‐propanol, iso‐propanol, and n‐butanol, respectively, as polar modifier in the hexane mobile phase. The results revealed that (S,S)‐Whelk O1 was less than universal and only hexaconazole and triadimenol underwent enantioseparation. Among the self‐prepared cellulose derivative columns used, the enantiomeric resolution capacities for the studied analytes generally decreased in the order CDMPC > CTPC > CTMB > CTB. The best enantioseparation of the analytes was mostly obtained on CDMPC and none of them were enantioseparated on CTB. The chiral recognition mechanisms between the analytes and the chiral selectors are discussed.
Extraction of hydroxyaromatic compounds in river water by liquid–liquid–liquid microextraction with automated movement of the acceptor and the donor phase
Authors: Melwanki Mahaveer B. , Huang Shang‐Da
Published: August 2006

Liquid–liquid–liquid microextraction with automated movement of the acceptor and the donor phase technique is described for the extraction of six hydroxyaromatic compounds in river water using a disposable and ready to use hollow fiber. Separation and quantitative analyses were performed using LC with UV detection at 254 nm. Analytes were extracted from the acidified sample solution (donor phase) into the organic solvent impregnated in the pores of the hollow fiber and then back extracted into the alkaline solution (acceptor phase) inside the lumen of the hollow fiber. The fiber was held by a conventional 10 μL LC syringe. The acceptor phase was sandwitched between the plunger and a small volume of the organic solvent (microcap). The acceptor solution was repeatedly moved in and out of the hollow fiber using a syringe pump. This movement provides a fresh acceptor phase to come in contact with the organic phase and thus enhancing extraction kinetics thereby leading to the improvement in enrichment of the analytes. The microcap separates the acceptor phase and the donor phase in addition to being partially responsible for mass transfer of the analytes from the donor solution to the acceptor solution. Under stirring, a fresh donor phase will enter through the open end of the fiber that will also contribute to the mass transfer. Various parameters affecting the extraction efficiency viz type of organic solvent, extraction time, stirring speed, effect of sodium chloride, and concentration of donor and acceptor phases were studied. RSD (3.9–5.6%), correlation coefficient (0.995–0.997), detection limit (2.0–51.2 ng/mL), enrichment factor (339–630), relative recovery (93.2–97.9%), and absolute recovery (33.9–63.0%) have also been investigated. The developed method was applied for the analysis of river water.
Separation of parabens in capillary electrochromatography using poly(styrene‐divinylbenzene‐methacrylic acid) monolithic column
Authors: Huang Hsi‐Ya , Huang I‐Yun , Lin Heng Yi
Published: August 2006

In this study, a series of poly(styrene‐divinylbenzene‐methacrylic acid) monolithic capillaries was used as the separation column of CEC for the analyses of parabens in commercial pharmaceutical and cosmetic products. The results showed that the chromatographic characteristics of these analytes were strongly affected by the preparation condition of the monolithic column including monomer content, porogenic solvent composition, and polymerization time. Baseline separations were markedly sped up by lowering the polymerization time without any obvious loss of resolution. Furthermore, mobile‐phase composition (pH, ACN, and electrolyte concentration) was also able to effectively improve the separation behavior. Similar to the influence of lowering the polymerization time, retention times for all analytes were significantly shortened in the CEC method by decreasing the electrolyte concentration in the mobile phase.
Investigating the Interactions of Hyaluronan Derivatives with Biomolecules. The Use of Diffusional NMR Techniques
Authors: Taglienti Anna , Cellesi Francesco , Crescenzi Vittorio , Sequi Paolo , Valentini Massimiliano , Tirelli Nicola
Published: August 2006

Summary: The interactions between a biomaterial and biomolecules present in body fluids often determine the fate of the biomaterial. This paper presents a study on hyaluronan (HA)‐containing materials (in soluble or colloidal form) that focuses on their interactions with lipids and proteins and for the first time uses PFG NMR as an analytical technique for probing these events. The interactions of HA‐based polymers with phospholipids (DPPC and DPPG liposomes) are shown to depend both on charge and hydrophobicity factors. Despite the difference in behavior between albumin (substantially non‐adhesive) and fibrinogen (adhesive), the interactions of the polymers with proteins do not seem to be based on hydrophobic effects but on surface polar interactions.

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Immobilized Hyperbranched Glycoacrylate Films as Bioactive Supports
Authors: Muthukrishnan Sharmila , Nitschke Mirko , Gramm Stefan , Özyürek Zeynep , Voit Brigitte , Werner Carsten , Müller Axel H. E.
Published: August 2006

Summary: We report on the low‐pressure plasma immobilization, characterization and application of thin films of hyperbranched glycoacrylates, poly(3‐O‐acryloyl‐α,β‐D‐glucopyranoside) (AGlc), on PTFE‐like fluorocarbon surfaces. This method is an efficient and versatile way to immobilize sugar‐carrying branched acrylates as thin films of approximately 5 nm thickness on polymeric substrates while the functional groups and properties of the immobilized molecules are largely retained. The extent of poly(AGlc) degradation during plasma immobilization was investigated using FTIR‐ATR spectroscopy and XPS. The thickness and topography of the immobilized films were characterized using spectroscopic ellipsometry and SFM, respectively. Studies of protein adsorption, as well as cell adhesion and proliferation on the poly(AGlc) surfaces, showed that these materials are suitable for the control of biointerfacial phenomena.

Fluorescence images of fibronectin adsorbed on to the branched glycoacrylate with a mask.

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Fluorescence images of fibronectin adsorbed on to the branched glycoacrylate with a mask.
Alginate Hydrogels as Biomaterials
Authors: Augst Alexander D. , Kong Hyun Joon , Mooney David J.
Published: August 2006

Summary: Alginate hydrogels are proving to have a wide applicability as biomaterials. They have been used as scaffolds for tissue engineering, as delivery vehicles for drugs, and as model extracellular matrices for basic biological studies. These applications require tight control of a number of material properties including mechanical stiffness, swelling, degradation, cell attachment, and binding or release of bioactive molecules. Control over these properties can be achieved by chemical or physical modifications of the polysaccharide itself or the gels formed from alginate. The utility of these modified alginate gels as biomaterials has been demonstrated in a number of in vitro and in vivo studies.

Micro‐CT images of bone‐like constructs that result from transplantation of osteoblasts on gels that degrade over a time frame of several months leading to improved bone formation.

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Micro‐CT images of bone‐like constructs that result from transplantation of osteoblasts on gels that degrade over a time frame of several months leading to improved bone formation.
Cover Picture: Macromol. Chem. Phys. 15/2006
Authors: Moncada Edwin , Quijada Raúl , Lieberwirth Ingo , Yazdani‐Pedram Mehrdad
Published: August 2006

Cover: Compatibilizing effect of itaconic acid grafted polypropylene on the degree of dispersion of clays such as montmorillonite and hectorite in polypropylene/clay nanocomposites was studied. The figure depicts possible interaction of the clay surface with the polar groups of the grafted polypropylene. The morphology of the resulting nanocomposite is also shown. Further details can be found in the Full Paper by E. Moncada, R. Quijada,* I. Lieberwirth, and M. Yazdani‐Pedram* on page 1376.
Use of Functionalized Metallocene Copolymers from Ethylene and Polar Olefins as Compatibilizers for Low‐Density‐Polyethylene/Starch and Low‐Density‐Polyethylene/Dextran Blends
Authors: Domínguez Ana María , Quijada Raúl , Yazdani‐Pedram Mehrdad
Published: August 2006

Summary: Functionalized metallocene copolymers synthesized from ethylene with 5‐hexen‐1‐ol and ethylene with 10‐undecen‐1‐ol were used as compatibilizers in LDPE/starch and LDPE/dextran blends in order to improve the interfacial adhesion between hydrophobic LDPE and hydrophilic natural polymers. An increase in tensile modulus and a slight decrease in tensile strength was observed when poly[ethylene‐co‐(10‐undecen‐1‐ol)] was added to a 70:30 wt.‐% LDPE/dextran blend, whereas the addition of poly[ethylene‐co‐(5‐hexen‐1‐ol)] as compatibilizer resulted in obtaining a more rigid material with a slightly higher modulus. Scanning electron microscopy of modified dextran blends containing 3 wt.‐% of both compatibilizers showed some degree of phase cocontinuity. Enhanced interfacial adhesion and decrease in particle size of starch was observed when 5 wt.‐% of poly [ethylene‐co‐(5‐hexen‐1‐ol)] copolymer was used as the compatibilizer in starch blends. The crystallization temperature of LDPE, determined by DSC, was shifted to a slightly higher temperature as a consequence of the addition of the compatibilizers. The existence of phase segregation was also revealed by thermal analysis when 5 wt.‐% of the copolymers were used as blend modifiers.

SEM micrograph of 70:30 wt.‐% LDPE/dextran blend with added poly[ethylene‐co‐(5‐hexen‐1‐ol)] compatibilizer.

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SEM micrograph of 70:30 wt.‐% LDPE/dextran blend with added poly[ethylene‐co‐(5‐hexen‐1‐ol)] compatibilizer.
Notexin causes greater myotoxic damage and slower functional repair in mouse skeletal muscles than bupivacaine
Authors: Plant David R. , Colarossi Fiona E. , Lynch Gordon S.
Published: August 2006

Although the myotoxins bupivacaine and notexin are employed for studying processes that regulate muscle regeneration after injury, no studies have compared their efficacy in causing muscle damage or assessing functional regeneration in mouse skeletal muscles. Bupivacaine causes extensive injury in rat muscles but its effects on mouse muscles are variable. We compared functional and morphological properties of regenerating mouse extensor digitorum longus (EDL) muscles after notexin or bupivacaine injection and tested the hypothesis that muscle damage would be more extensive and functional repair less complete after notexin injection. Bupivacaine caused degeneration of 45% of fibers and reduced maximum force (Po) to 42% of control after 3 days. In contrast, notexin caused complete fiber breakdown and loss of functional capacity after 3 days (P < 0.05). At 7 and 10 days after bupivacaine, Po was restored to 65% and 71% of control, respectively, whereas Po of notexin‐injected muscles was only 10% and 39% of control at these time‐points, respectively (P < 0.05). At 7 and 10 days after bupivacaine, ∼30% of fibers were centrally nucleated (regenerating), whereas notexin‐injected muscles were comprised entirely of regenerating fibers (P < 0.05). The results demonstrate that notexin causes a more extensive and complete injury than bupivacaine, and is a useful model for studying muscle regeneration in mice. Muscle Nerve, 2006
Elevated skeletal muscle phosphodiesters in adults using statin medications
Authors: Slade Jill M. , Delano Mark C. , Meyer Ronald A.
Published: August 2006

Elevated skeletal muscle phosphodiesters (PDE) have previously been reported with muscle‐related disorders. Myalgia is a side effect of using statin cholesterol‐lowering medications and, therefore, statin use may be associated with increased skeletal muscle PDE. The effect of cholesterol‐lowering drugs on skeletal muscle phosphorus metabolites was determined with 31P magnetic resonance spectroscopy. Resting 31P metabolites of the anterior compartment muscles were measured in two groups (n = 20; age, 49 ± 2 years); half were taking statins and the other half were not on these agents. Muscle PDE was 57% greater in the statin group than the control group. These data suggest that statin use increases muscle PDE. Our findings are particularly relevant due to the increasing use and higher dosing of statin medications. Further prospective studies should be performed to document a causal relationship between elevated PDE and statin use, in addition to quantifying correlates to muscle function. Muscle Nerve, 2006
Peripheral nerve injuries: A retrospective survey of 456 cases
Authors: Kouyoumdjian João Aris
Published: August 2006

This 16‐year retrospective study reports the data on 456 consecutive patients with 557 peripheral nerve injuries (PNIs) between 1989 and 2004. Most patients were men (74%) and the mean age was 32.4 years. In 83% of cases the PNIs were isolated; combined lesions most commonly involved the ulnar and median nerves. Upper‐limb PNIs occurred in 73.5% of cases; the ulnar nerve was most often injured, either singly or in combination. Vehicle accidents affecting the brachial plexus or radial, sciatic, facial, and peroneal nerves were the most common cause of injury. Penetrating trauma commonly affected the ulnar and median nerves; falls and gunshot wounds frequently affected the ulnar, radial, and median nerves; and sports injuries, particularly soccer, affected mainly the peroneal and tibial nerves. More than half of the brachial plexus lesions after vehicular accidents were from motorcycle crashes. Muscle Nerve, 2006
Assessing neuromuscular disease with multifrequency electrical impedance myography
Authors: Esper Gregory J. , Shiffman Carl A. , Aaron Ronald , Lee Kyungmouk S. , Rutkove Seward B.
Published: August 2006

Electrical impedance myography (EIM) is a noninvasive technique for neuromuscular assessment in which low‐intensity alternating current is applied to a muscle and the consequent surface voltage patterns are evaluated. Previous work using a single frequency of 50 kHZ has demonstrated quantitative correlation of EIM parameters with disease status. In this investigation we examined the use of multifrequency EIM, studying a prototypical neurogenic disease (amyotrophic lateral sclerosis, ALS) and myopathic disorder (inflammatory myopathy, IM). Eleven ALS patients, 7 IM patients, and 46 normal subjects participated in the study. Although disease‐specific patterns were not identified such that IM could be differentiated from ALS, impedance vs. frequency patterns for diseased subjects differed substantially from those of the age‐matched normal subjects, with the greatest alterations occurring in the most severe cases. Multifrequency EIM may be well‐suited to serve as an easily applied technique to assess disease severity in a variety of neuromuscular conditions. Muscle Nerve, 2006
Machine scheduling with an availability constraint and job delivery coordination
Authors: Wang Xiuli , Cheng T. C. Edwin
Published: August 2006

In this paper we study the scheduling problem that considers both production and job delivery at the same time with machine availability considerations. Only one vehicle is available to deliver jobs in a fixed transportation time to a distribution center. The vehicle can load at most K jobs as a delivery batch in one shipment due to the vehicle capacity constraint. The objective is to minimize the arrival time of the last delivery batch to the distribution center. Since machines may not always be available over the production period in real life due to preventive maintenance, we incorporate machine availability into the models. Three scenarios of the problem are studied. For the problem in which the jobs are processed on a single machine and the jobs interrupted by the unavailable machine interval are resumable, we provide a polynomial algorithm to solve the problem optimally. For the problem in which the jobs are processed on a single machine and the interrupted jobs are nonresumable, we first show that the problem is NP‐hard. We then propose a heuristic with a worst‐case error bound of 1/2 and show that the bound is tight. For the problem in which the jobs are processed on either one of two parallel machines, where only one machine has an unavailable interval and the interrupted jobs are resumable, we propose a heuristic with a worst‐case error bound of 2/3. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007
Thermal flutter analysis of large‐scale space structures based on finite element method
Authors: Li Wei , Xiang Zhihai , Chen Lejin , Xue Mingde
Published: August 2006

During the orbital day–night crossing period, the suddenly applied thermal loading is apt to introducing vibration on flexible appendages of large‐scale space structures. This kind of thermally‐induced vibration is a typical failure of modern spacecrafts. However, owing to the complexity of this problem, many earlier researches study only the vibration of simplified beam models, which can hardly describe the performance of practical structures. This paper aims at using the finite element method to analyse the non‐linear vibration of practical thin‐walled large‐scale space structures subjected to suddenly applied thermal loading. In this study, the coupling effect between structural deformations and the incident normal solar heat flux is considered; the necessary condition of thermally‐induced vibration is verified; and the criterion of thermal flutter is established. Copyright © 2006 John Wiley & Sons, Ltd.
Co‐evolutionary algorithm for structural damage identification using minimal physical testing
Authors: Kouchmeshky B. , Aquino W. , Bongard J. C. , Lipson H.
Published: August 2006

The problem of damage identification using minimum test data is studied in this work. Data sparsity in damage identification applications commonly results in inverse problems that are mathematically ill‐posed (e.g. non‐unique solutions). Although solution non‐uniqueness may be addressed by performing multiple tests on a structure, it is not trivial to decide which tests to carry out given that actual physical testing is costly. This problem is addressed in this work through a new co‐evolutionary algorithm that interactively searches for damage scenarios and optimum physical tests. The algorithm is composed of two stages: the estimation phase, which searches for damage scenarios that can predict current physical tests, and the exploration phase, which searches for tests that increase the level of information about the damaged system. The feasibility of the methodology is demonstrated using numerical examples. Copyright © 2006 John Wiley & Sons, Ltd.
A simple and efficient approach to capturing bonding effect in naturally microstructured sands by discrete element method
Authors: Jiang Mingjing , Yu Hai‐Sui , Leroueil Serge
Published: August 2006

A discrete element modelling of naturally microstructured sands is very important to geomechanics. This paper presents a simple discrete element model for naturally microstructured sands with the aim to efficiently capture the effect of cementation between particles (bonds). First, a simple bond contact model was proposed by introducing a rigid‐plastic bond element into the conventional contact model for dry granular material. Second, efficient numerical techniques were investigated to implement this contact model into the distinct element method (DEM). Then, a two‐dimensional DEM code was developed to simulate a series of isotropic compression tests on the materials of different densities and bonding strengths. Finally, the DEM results were examined in comparison with the experimental data on artificially bonded sands obtained by Rotta et al. (Géotechnique 2003; 53(5):493–502). In addition, we discussed the yielding mechanism, the Coop and Willson criteria on weak/strong bonding (J. Geotech. Eng. (ASCE) 2003; 129(11):1010–1019) and the strong bonding phenomenon observed by Rotta et al. based on the DEM data. The study shows that the DEM model is able to capture the main features of naturally microstructured sands, such as variations of yielding and bulk modulus against bonding strength or material density. In addition, it is shown that the gross yielding (the yielding defined in terms of strains) is largely related to bond breakage; Coop and Willson criteria are generally reasonable; and the strong bonding in the experimental data obtained by Rotta et al. comes from that their bonded materials start at different points on the same compression line. Copyright © 2006 John Wiley & Sons, Ltd.
Damage detection by the topology design formulation using modal parameters
Authors: Lee Joong Seok , Kim Jae Eun , Kim Yoon Young
Published: August 2006

The feasibility of using the topology design method for structural damage identification is investigated for the first time. The finite element model of an undamaged structure and some point‐frequency response functions of a damaged structure are assumed to be available. To carry out the feasibility study, the topology optimization formulation suitable for structural damage detection is newly set up, where both resonances and anti‐resonances are used as the damage indication modal parameters. An idea to progressively reduce the candidate damaged elements is also developed to improve the accuracy and efficiency of the proposed method. Copyright © 2006 John Wiley & Sons, Ltd.
Level set X‐FEM non‐matching meshes: application to dynamic crack propagation in elastic–plastic media
Authors: Prabel B. , Combescure A. , Gravouil A. , Marie S.
Published: August 2006

This paper develops two aspects improving crack propagation modelling with the X‐FEM method. On the one hand, it explains how one can use at the same time a regular structured mesh for a precise and efficient level set update and an unstructured irregular one for the mechanical model. On the other hand, a new numerical scheme based on the X‐FEM method is proposed for dynamic elastic–plastic situations. The simulation results are compared with two experiments on PMMA for which crack speed and crack path are provided. Copyright © 2006 John Wiley & Sons, Ltd.
Refined global–local higher‐order theory and finite element for laminated plates
Authors: Zhen Wu , Wanji Chen
Published: August 2006

Based on completely three‐dimensional elasticity theory, a refined global–local higher‐order theory is presented as enhanced version of the classical global–local theory proposed by Li and Liu (Int. J. Numer. Meth. Engng. 1997; 40:1197–1212), in which the effect of transverse normal deformation is enhanced. Compared with the previous higher‐order theory, the refined theory offers some valuable improvements these are able to predict accurately response of laminated plates subjected to thermal loading of uniform temperature. However, the previous higher‐order theory will encounter difficulty for this problem. A refined three‐noded triangular element satisfied the requirement of C1 weak‐continuity conditions in the inter‐element is also presented. The results of numerical examples of moderately thick laminated plates and even thick plates with span/thickness ratios L/h = 2 are given to show that in‐plane stresses and transverse shear stresses can be reasonably predicted by the direct constitutive equation approach without smooth technique. In order to accurately obtain transverse normal stresses, the local equilibrium equation approach in one element is employed herein. Copyright © 2006 John Wiley & Sons, Ltd.
A rotation‐free shell triangle for the analysis of kinked and branching shells
Authors: Flores Fernando G. , Oñate Eugenio
Published: August 2006

This paper extends the capabilities of previous BST and EBST rotation‐free thin shell elements to the analysis of kinked and branching surfaces. The computation of the curvature tensor is first redefined in terms of the angle change between the normals at the adjacent elements. This allows to deal with arbitrary large angles between adjacent elements and to treat kinked surfaces. A relative stiffness between elements is introduced to consider non‐homogeneous surfaces. This idea is latter generalized to deal with branching shells. Several linear and non‐linear examples are presented showing that the formulation leads to the correct results. Copyright © 2006 John Wiley & Sons, Ltd.
The method of fundamental solutions for inverse source problems associated with the steady‐state heat conduction
Authors: Jin Bangti , Marin Liviu
Published: August 2006

This paper presents the use of the method of fundamental solutions (MFS) for recovering the heat source in steady‐state heat conduction problems from boundary temperature and heat flux measurements. It is well known that boundary data alone do not determine uniquely a general heat source and hence some a priori knowledge is assumed in order to guarantee the uniqueness of the solution. In the present study, the heat source is assumed to satisfy a second‐order partial differential equation on a physical basis, thereby transforming the problem into a fourth‐order partial differential equation, which can be conveniently solved using the MFS. Since the matrix arising from the MFS discretization is severely ill‐conditioned, a regularized solution is obtained by employing the truncated singular value decomposition, whilst the optimal regularization parameter is determined by the L‐curve criterion. Numerical results are presented for several two‐dimensional problems with both exact and noisy data. The sensitivity analysis with respect to two solution parameters, i.e. the number of source points and the distance between the fictitious and physical boundaries, and one problem parameter, i.e. the measure of the accessible part of the boundary, is also performed. The stability of the scheme with respect to the amount of noise added into the data is analysed. The numerical results obtained show that the proposed numerical algorithm is accurate, convergent, stable and computationally efficient for solving inverse source problems in steady‐state heat conduction. Copyright © 2006 John Wiley & Sons, Ltd.
A large deformation solid‐shell concept based on reduced integration with hourglass stabilization
Authors: Reese Stefanie
Published: August 2006

In this paper a new eight‐node (brick) solid‐shell finite element formulation based on the concept of reduced integration with hourglass stabilization is presented. The work focuses on static problems. The starting point of the derivation is the three‐field variational functional upon which meanwhile established 3D enhanced strain concepts are based. Important additional assumptions are made to transfer the approach into a powerful solid‐shell. First of all, a Taylor expansion of the first Piola–Kirchhoff stress tensor with respect to the normal through the centre of the element is carried out. In this way the stress becomes a linear function of the shell surface co‐ordinates whereas the dependence on the thickness co‐ordinate remains non‐linear. Secondly, the Jacobian matrix is replaced by its value in the centre of the element. These two assumptions lead to a computationally efficient shell element which requires only two Gauss points in the thickness direction (and one Gauss point in the plane of the shell element). Additionally three internal element degrees‐of‐freedom have to be determined to avoid thickness locking. One important advantage of the element is the fact that a fully three‐dimensional stress state can be modelled without any modification of the constitutive law. The formulation has only displacement degrees‐of‐freedom and the geometry in the thickness direction is correctly displayed. Copyright © 2006 John Wiley & Sons, Ltd.
Hybrid BEM for the early stage of unsteady transport process
Authors: Peratta Andrés , Popov Viktor
Published: August 2006

This paper presents a new approach for solving the early stage of 3D time‐dependent transport problems in non‐homogeneous fractured porous media in which the initial distribution of concentration presents discontinuous jump at the interface of two regions of transport properties differing in several orders of magnitude. The goal of this formulation is to overcome the problems of different scales and apparent large flux during early time by combining the 3D dual reciprocity boundary element method and a semi‐analytical solution of the time‐dependent advection–diffusion equation, employing a two‐level finite difference time integration scheme. Theoretical background, validation results and practical applications for the advection–diffusion equation in fractured and continuous porous media are reported. The results show advantages for relatively large‐scale models and complex geometries. Copyright © 2006 John Wiley & Sons, Ltd.
Crystallisation kinetics of novel branched poly(ethylene terephthalate): a small‐angle X‐ray scattering study
Authors: Hanley Tracey L , Forsythe John S , Sutton David , Moad Graeme , Burford Robert P , Knott Robert B
Published: August 2006

Three types of poly(ethylene terephthalate) (PET) were investigated: linear (unprocessed) bottle‐grade PET (intrinsic viscosity, IV ∼ 0.82 dL g−1); a branched PET produced from linear PET by reactive extrusion with 0.4% w/w pyromellitic dianhydride and pentaerythritol in 5:1 molar ratio (IV ∼ 0.97 dL g−1); and a control sample produced from the same linear PET by extrusion under the same conditions without the reactive agents (IV ∼ 0.71 dL g−1). A key finding is that the reactive extrusion process, presumably as a consequence of branching and branch distribution, significantly modifies the crystallisation kinetics and changes the final morphology. Using small‐angle X‐ray scattering (SAXS) and differential scanning calorimetry (DSC), the crystallisation kinetics of PET was monitored from the melt (270 °C) to a crystallisation temperature of either 205 or 210 °C. The IV of the branched PET was ∼ 21% greater than that of the unprocessed PET, and the rate of melt crystallisation (from DSC measurements) was 510 s for the branched, 528 s for the control, and 640 s for the unprocessed PET. The lamellae spacings measured from the equilibrium SAXS patterns were ∼160 ± 10 Å for the branched PET and ∼180 ± 10 Å for the unprocessed PET. Such properties offer the potential for new applications requiring high‐melt‐strength PET. Copyright © 2006 Society of Chemical Industry
Structure and enzymatic properties of a chimeric bacteriophage RB69 DNA polymerase and single‐stranded DNA binding protein with increased processivity
Authors: Sun Siyang , Geng Linda , Shamoo Yousif
Published: August 2006

In vivo, replicative DNA polymerases are made more processive by their interactions with accessory proteins at the replication fork. Single‐stranded DNA binding protein (SSB) is an essential protein that binds tightly and cooperatively to single‐stranded DNA during replication to remove adventitious secondary structures and protect the exposed DNA from endogenous nucleases. Using information from high resolution structures and biochemical data, we have engineered a functional chimeric enzyme of the bacteriophage RB69 DNA polymerase and SSB with substantially increased processivity. Fusion of RB69 DNA polymerase with its cognate SSB via a short six amino acid linker increases affinity for primer‐template DNA by sixfold and subsequently increases processivity by sevenfold while maintaining fidelity. The crystal structure of this fusion protein was solved by a combination of multiwavelength anomalous diffraction and molecular replacement to 3.2 Å resolution and shows that RB69 SSB is positioned proximal to the N‐terminal domain of RB69 DNA polymerase near the template strand channel. The structural and biochemical data suggest that SSB interactions with DNA polymerase are transient and flexible, consistent with models of a dynamic replisome during elongation. Proteins 2006. © 2006 Wiley‐Liss, Inc.
A continuous‐flow crushing device for on‐line δ2H analysis of fluid inclusion water in speleothems
Authors: Vonhof Hubert B. , van Breukelen Martin R. , Postma Onno , Rowe Peter J. , Atkinson Tim C. , Kroon Dick
Published: August 2006

A method for the isotope analysis of fluid inclusion water in speleothem calcite is presented. The technique is based on a commercially available continuous‐flow pyrolysis furnace (ThermoFinnigan TC‐EA). The main adaptation made to the standard TC‐EA configuration is the addition of a crusher and cold trap unit, which is connected to the carrier gas inlet at the top of the TC‐EA reactor tube. A series of tests conducted with this device shows that: (1) standard waters, injected in the crusher, and passed through a cryogenic trapping routine, yield accurate δ2H values; (2) crushed cubes of speleothem calcite from two Peruvian caves with rather dissimilar seepage water δ2H values yield fluid inclusion δ2H values in good accordance with these drip waters. The clear advantage of this continuous‐flow technique for fluid inclusion isotope analysis is that it is relatively quick compared with other techniques. Since the conditions of water sample introduction into the TC‐EA are identical for δ2H and δ18O analysis, we expect that only limited adaptations to the extraction procedure are required to provide δ18O analysis of fluid inclusion samples with the same device. Copyright © 2006 John Wiley & Sons, Ltd.