bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards an integrated GIS‐based coastal forecast workflow
Authors: Allen Gabrielle , Bogden Philip , Creager Gerry , Dekate Chirag , Jesch Carola , Kaiser Hartmut , McLaren Jon , Perrie Will , Stone Gregory W. , Zhang Xiongping
Published: June 2008

The SURA Coastal Ocean Observing and Prediction (SCOOP) program is using geographical information system (GIS) technologies to visualize and integrate distributed data sources from across the United States and Canada. Hydrodynamic models are run at different sites on a developing multi‐institutional computational Grid. Some of these predictive simulations of storm surge and wind waves are triggered by tropical and subtropical cyclones in the Atlantic and the Gulf of Mexico. Model predictions and observational data need to be merged and visualized in a geospatial context for a variety of analyses and applications. A data archive at LSU aggregates the model outputs from multiple sources, and a data‐driven workflow triggers remotely performed conversion of a subset of model predictions to georeferenced data sets, which are then delivered to a Web Map Service located at Texas A&M University. Other nodes in the distributed system aggregate the observational data. This paper describes the use of GIS within the SCOOP program for the 2005 hurricane season, along with details of the data‐driven distributed dataflow and workflow, which results in geospatial products. We also focus on future plans related to the complimentary use of GIS and Grid technologies in the SCOOP program, through which we hope to provide a wider range of tools that can enhance the tools and capabilities of earth science research and hazard planning. Copyright © 2008 John Wiley & Sons, Ltd.
Toward exploitation of cell multi‐processor array in time‐consuming applications by using CNN model
Authors: Nagy Zoltán , Kék László , Kincses Zoltán , Kiss András , Szolgay Péter
Published: June 2008

Array computers can be useful in the solution of numerical spatio‐temporal problems such as the state equation of the CNN or partial differential equations (PDE). IBM has recently introduced the cell broadband engine (cell BE) architecture, which contains eight identical vector processors in an array structure. In this paper the implementation of CNN simulation kernel on the cell BE is described. The simulation kernel is optimized according to the special requirements of the cell BE and can implement linear as well as nonlinear (piecewise linear) templates. In addition, the 2‐D Princeton ocean model is implemented on the cell BE. The area/speed/power tradeoffs of our solution and different hardware implementations are also compared. Copyright © 2008 John Wiley & Sons, Ltd.
Development of the corneal stroma, and the collagen–proteoglycan associations that help define its structure and function
Authors: Quantock Andrew J. , Young Robert D.
Published: June 2008

The cornea of the eye is a unique, transparent connective tissue. It is comprised predominantly of collagen fibrils, remarkably uniform in diameter and regularly spaced, organized into an intricate lamellar array. Its establishment involves a precisely controlled sequence of developmental events in which the embryonic cornea undergoes major structural transformations that ultimately determine tissue form and function. In this article, we will review corneal developmental dynamics from a structural perspective, consider the roles and interrelationships of collagens and proteoglycans, and comment on contemporary concepts and current challenges pertinent to developmental processes that result in an optically clear, mature cornea. Developmental Dynamics 237:2607–2621, 2008. © 2008 Wiley‐Liss, Inc.
The zebrafish embryo as a dynamic model of anoxia tolerance
Authors: Mendelsohn Bryce A. , Kassebaum Bethany L. , Gitlin Jonathan D.
Published: June 2008

Developing organisms depend upon a delicate balance in the supply and demand of energy to adapt to variable oxygen availability, although the essential mechanisms determining such adaptation remain elusive. In this study, we examine reversible anoxic arrest and dynamic bioenergetic transitions during zebrafish development. Our data reveal that the duration of anoxic viability corresponds to the developmental stage and anaerobic metabolic rate. Diverse chemical inhibitors of mitochondrial oxidative phosphorylation induce a similar arrest in normoxic embryos, suggesting a pathway responsive to perturbations in aerobic energy production rather than molecular oxygen. Consistent with this concept, arrest is accompanied by rapid activation of the energy‐sensing AMP‐activated protein kinase pathway, demonstrating a potential link between the sensing of energy status and adaptation to oxygen availability. These observations permit mechanistic insight into energy homeostasis during development that now enable genetic and small molecule screens in this vertebrate model of anoxia tolerance. Developmental Dynamics 237:1780–1788, 2008. © 2008 Wiley‐Liss, Inc.
Identification and characterization of subpopulations of Pax3 and Pax7 expressing cells in developing chick somites and limb buds
Authors: Galli Lisa M. , Knight Sara R. , Barnes Tiffany L. , Doak Allison K. , Kadzik Rachel S. , Burrus Laura W.
Published: June 2008

Pax3 and Pax7 are closely related paired‐boxed family transcription factors that are known to play important roles in embryonic and adult myogenesis. Previous reports describing the expression of Pax3 and Pax7 transcripts reveal expression in many overlapping domains. In this manuscript, we extend these studies by examining the protein expression profiles for Pax3 and Pax7 in developing chick somites and limbs with cellular resolution. Our studies show the existence of distinct subpopulations of cells in the somite and developing limb that are defined by the relative expression levels of Pax3 and Pax7. We also show that Pax3 and Pax7 negatively regulate each other's expression in the dermomyotome, thus providing a possible mechanism for the maintenance of observed expression patterns in the dermomyotome. Further characterization of Pax3‐ and/or Pax7‐positive cells in the dermomyotome and myotome with respect to proliferation and differentiation reveals subpopulations of cells with distinct properties. Developmental Dynamics 237:1862–1874, 2008. © 2008 Wiley‐Liss, Inc.
Characteristics and key findings for ‘Psychological interventions for needle‐related procedural pain and distress in children and adolescents’
Authors: van Dalen E. C. , Offringa M.
Published: June 2008

These are the characteristics and key findings for a Cochrane review published in this issue of EBCH, first published as: Uman LS, Chambers CT, McGrath PJ, Kisely S. Psychological interventions for needle‐related procedural pain and distress in children and adolescents. Cochrane Database of Systematic Reviews 2006, Issue 4. Art. No.: CD005179. DOI: 10.1002/14651858.CD005179.pub2.

Further information for this Cochrane review is available in this issue of EBCH in the accompanying EBCH Summary and Commentary articles. Copyright © 2008 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. The Cochrane Collaboration
Two commentaries on ‘Corticosteroids for acute bacterial meningitis’
Authors: Vaudry Wendy , Corel Linda J. A. , de Hoog Matthijs
Published: June 2008

This is a commentary on a Cochrane review, published in this issue of EBCH, first published as: van de Beek D, de Gans J, McIntyre P, Prasad K. Corticosteroids for acute bacterial meningitis. Cochrane Database of Systematic Reviews 2007, Issue 1. Art. No.: CD004405. DOI: 10.1002/14651858.CD004405.pub2.

Further information for this Cochrane review is available in this issue of EBCH in the accompanying EBCH Summary and Characteristics and Key Findings Tables articles. Copyright © 2008 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. The Cochrane Collaboration
Studies on the Biosynthesis of Bovilactone‐4,4 and Related Fungal Meroterpenoids
Authors: Lang Martin , Mühlbauer Andrea , Jägers Erhard , Steglich Wolfgang
Published: June 2008

The initial step in the biosynthesis of suillin (1), boviquinone‐4 (2) and bovilactone‐4,4 (3) in Suillus species is the geranylgeranylation of 3,4‐dihydroxybenzoic acid at the 2‐position. Feeding experiments with advanced precursors have identified boviquinone‐4 and deacetylsuillin (9) as building blocks for the dilactone and catechol moieties, respectively, of bovilactone‐4,4 (3). In order to explain the failure of boviquinone‐4 (2) to incorporate side‐chain‐labelled deacetylsuillin (9#), an alternative sequence for the formation of 2 is proposed. During these experiments an interesting change in metabolism was noticed: after administration of larger quantities of aromatic carboxylic acids, the boviquinone‐4 present in the fruit bodies disappeared and de novo synthesis of bovilactone‐4,4 occurred. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Uncatalyzed Strecker‐Type Reaction of N,N‐Dialkylhydrazones in Pure Water
Authors: Marqués‐López Eugenia , Herrera Raquel P. , Fernández Rosario , Lassaletta José M.
Published: June 2008

Aldehyde and ketone N,N‐dialkylhydrazones behave as a stable class of imine surrogates exhibiting a unique reactivity in the Strecker reaction with in situ generated HCN, that proceeds in pure water in the absence of co‐solvents, catalysts or promoters. Experimental evidence suggests that the reaction is assisted by an intramolecular activation of HCN by the dialkyl amino lone pair.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A Straightforward and General Strategy Towards 1,5‐Dithio‐1‐enopyranosides
Authors: Buchotte Marie , Muzard Murielle , Plantier‐Royon Richard
Published: June 2008

The synthesis of a new class of thiosugar derivatives, 1,5‐dithio‐1‐enopyranosides, has been achieved in a two‐step sequence from easily available aldofuranoses. In the first step, a carbohydrate‐derived ketene dithioacetal was formed by Peterson olefination of an aldofuranose and a lithiated α‐silyl thioacetal. In the second step, intramolecular nucleophilic substitution of an activated hydroxy group by a sulfur atom of the ketene dithioacetal function led to the target compounds in good yields.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Combination of RCM and the Pauson–Khand Reaction: One‐Step Synthesis of Tricyclic Structures
Authors: Rosillo Marta , Arnáiz Eduardo , Abdi Delbrin , Blanco‐Urgoiti Jaime , Domínguez Gema , Pérez‐Castells Javier
Published: June 2008

The combination of ring‐closing metathesis (RCM) followed by an intramolecular Pauson–Khand reaction gives direct entry to tricyclic compounds. The RCM was carried out on a hexacarbonylcobalt‐complexed alkyne, this complex acting as a protecting group against enyne metathesis. The procedure was studied for dienynes containing heteroatoms and allows the building of [6,5,5] and [7,5,5] tricyclic systems. The feasibility of the process depends strongly on the nature of the substrate.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Benefits, variants and applications of cyclic delay diversity
Authors: Dammann Armin , Plass Simon , Sand Stephan , Raulefs Ronald
Published: June 2008

Cyclic delay diversity (CDDx) is a simple multiple antenna technologyxs which provides additional diversity in Rayleigh fading channels, and therefore, improves the system performance. We recall the principles of CDD and discuss the properties and impact of this transmit (TX) antenna diversity technology. Different applications motivate variations of the CDD principle. This variants are briefly introduced and discussed. We show the application to several types of wireless systems, in particular terrestrial digital video broadcasting, cellular mobile radio communications systems and a wireless communications system using adaptive bit loading (ABL). Simulation results highlight the benefits of CDD for these kind of systems. Copyright © 2008 John Wiley & Sons, Ltd.
Performance enhancement of spectral‐amplitude coding OCDMA system using novel PPM signalling
Authors: Cui K. , Leeson M. S. , Hines E. L.
Published: June 2008

A spectral‐amplitude coding (SAC) optical code‐division multiple‐access (OCDMA) system with M‐ary pulse‐position modulation (PPM) signalling is investigated. Novel combinatorial construction of optical signature codes is also presented, as that is applicable to both synchronous and asynchronous incoherent OCDMA. A union upper bound on the probability of error is then derived and the performance characteristics are discussed in the presence of multiple‐access interference (MAI) and intensity noise. The numerical results show that the bit‐error performance of the OCDMA system with proposed PPM coding outperforms that associated with on—off keying (OOK). Copyright © 2008 John Wiley & Sons, Ltd.
Tourism in the Canary Islands: forecasting using several seasonal time series models
Authors: Gil‐Alana Luis A. , Cunado Juncal , Perez de Gracia Fernando
Published: June 2008

This paper deals with the analysis of the number of tourists travelling to the Canary Islands by means of using different seasonal statistical models. Deterministic and stochastic seasonality is considered. For the latter case, we employ seasonal unit roots and seasonally fractionally integrated models. As a final approach, we also employ a model with possibly different orders of integration at zero and the seasonal frequencies. All these models are compared in terms of their forecasting ability in an out‐of‐sample experiment. The results in the paper show that a simple deterministic model with seasonal dummy variables and AR(1) disturbances produce better results than other approaches based on seasonal fractional and integer differentiation over short horizons. However, increasing the time horizon, the results cannot distinguish between the model based on seasonal dummies and another using fractional integration at zero and the seasonal frequencies. Copyright © 2008 John Wiley & Sons, Ltd.
Short‐term variability in isotopic composition of precipitation: A case study from the Midwestern United States
Authors: Iqbal M. Z.
Published: June 2008

Oxygen and deuterium isotopes in precipitation were analysed to define local isotopic trends in Iowa, US. The area is far inland from an oceanic source and the observed averages of δ18O and δ D are − 6·43‰ and − 41·35‰ for Ames, − 7·53‰ and − 51·33‰ for Cedar Falls, and − 6·01‰ and − 38·19‰ for Iowa City, respectively. Although these data generally follow global trends, they are different when compared to a semi‐arid mid‐continental location in North Platt, Nebraska. The local meteoric water lines of Iowa are δ D = 7·68 δ18O + 8·0 for Ames, δ D = 7·62 δ18O + 6·07 for Cedar Falls, and δ D = 7·78 δ18O + 8·61 for Iowa City. The current Iowa study compares well with a study conducted in Ames, Iowa, 10 years earlier. The differences between Iowa and Nebraska studies are attributed to a variable climate across the northern Great Plains ranging from sub‐humid in the east to semi‐arid in the west. Iowa being further east in the region is more strongly influenced by a moist sub‐humid to humid climate fed by the tropical air stream from the Gulf of Mexico. The average d‐excess values are 10·06‰ for Ames, 8·92‰ for Cedar Falls and 9·92‰ for Iowa City. Eighty seven percent of the samples are within the global d‐excess range of 0‰ and 20‰. The results are similar to previous studies, including those by National Atmospheric Deposition Programs and International Atomic Energy Agency. It appears that the impact of recycled water or secondary evaporation on δ18O values of area precipitation is minimal. Copyright © 2008 John Wiley & Sons, Ltd.
One‐step in situ synthesis and characterization of sponge‐like porous calcium phosphate scaffolds using a sol–gel and gel casting hybrid process
Authors: Wang Jianxin , Zhao Huichuan , Zhou Shaobing , Lu Xiong , Feng Bo , Duan Caihong , Weng Jie
Published: June 2008

In this article, a novel strategy to prepare porous calcium phosphate ceramics using a sol–gel and gel‐casting hybrid process is presented. The ceramic foams obtained using this method exhibited sponge‐like structure with uniform big pores and small pores distributed on the big pore walls. The sizes of big and small pores were within 500–800 and 50–300 μm, respectively. These kinds of porous calcium phosphate ceramics have shown better property in withstanding machining and better microstructures characterized by a very high degree of interconnection and optimal pore size for osteoconduction compared with those conventionally fabricated. The signification or importance of this study is reflected by one‐step in situ synthesis and the use of a sol–gel and gel casting hybrid process. Organic monomers, foaming agents, and surfactants are not required during this novel porous ceramic fabrication. The precursors themselves act as monomers, foaming agents, and surfactants. These advantages will offer a cheap and simple pathway for industrial manufacture. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Protein structure and dynamics studied by mass spectrometry: H/D exchange, hydroxyl radical labeling, and related approaches
Authors: Konermann Lars , Tong Xin , Pan Yan
Published: June 2008

Mass spectrometry (MS) plays a central role in studies on protein structure and dynamics. This review highlights some of the recent developments in this area, with focus on applications involving the use of electrospray ionization (ESI) MS. Although this technique involves the transformation of analytes into highly nonphysiological species (desolvated gas‐phase ions in the vacuum), ESI–MS can provide detailed insights into the solution‐phase behavior of proteins. Notably, the ionization process itself occurs in a structurally sensitive manner. An increased degree of solution‐phase unfolding is correlated with a higher level of protonation. Also, ESI allows the transfer of intact noncovalent complexes into the gas phase, thereby yielding information on binding partners, stoichiometries, and even affinities. A particular focus of this article is the use of hydrogen/deuterium exchange (HDX) methods and hydroxyl radical (·OH) labeling for monitoring dynamic and structural aspect of solution‐phase proteins. Conceptual similarities and differences between the two methods are discussed. We describe a simple method for the computational simulation of protein HDX patterns, a tool that can be helpful for the interpretation of isotope exchange data recorded under mixed EX1/EX2 conditions. Important aspects of ·OH labeling include a striking dependence on protein concentration, and the tendency of commonly used solvent additives to act as highly effective radical scavengers. If not properly controlled, both of these factors may lead to experimental artifacts. Copyright © 2008 John Wiley & Sons, Ltd.
Mechanisms regulating ApTrkl, a Trk‐like receptor in Aplysia sensory neurons
Authors: Nagakura Ikue , Ormond Jake , Sossin Wayne S.
Published: June 2008

An Aplysia Trk‐like receptor (ApTrkl) was previously shown to be involved in cell wide long‐term facilitation (LTF) and activation of ERK when serotonin (5‐HT) is applied to the cell soma. The current study investigated the regulation of ApTrkl by overexpressing the receptor and several variants in Aplysia sensory neuron cultures. Kinase activity–dependent constitutive activation of ApTrkl was observed mainly on the plasma membrane. These studies revealed two modes of receptor internalization: (1) kinase activity–dependent internalization and (2) 5‐HT‐dependent, kinase activity–independent internalization. Both modes of internalization were ligand independent, and the action of 5‐HT was mediated through G‐protein‐coupled receptors (GPCRs). On the other hand, methiothepin, an inverse agonist of 5‐HT GPCRs activated endogenous ApTrkl to the same extent as 5‐HT, suggesting a transactivation mechanism due to a novel coupling of GPCRs to receptor tyrosine kinase (RTK) activation that is also activated through inverse agonist binding. The neuropeptide sensorin could transiently activate ApTrkl but was not required for 5‐HT‐induced ApTrkl activation. © 2008 Wiley‐Liss, Inc.
Analysis of near‐surface diurnal temperature variations and trends in southern Mexico
Authors: Peralta‐Hernandez Ana Rosa , Balling Jr Robert C. , Barba‐Martinez Luis R.
Published: June 2008

We assembled daily maximum temperature, minimum temperature and precipitation records for 143 stations in southern Mexico over the period 1960–2004. We found that the average temperature for the region has increased linearly at a rate of 0.086 °C per decade with maximum temperatures increasing at twice that rate and minimum temperatures basically remaining unchanged. This results in a highly statistically significant increase in the diurnal temperature range of 0.160 °C per decade. We found that the variations and trends in maximum temperatures, minimum temperatures and the diurnal temperature range were generally unrelated to various measures of El Niño–Southern Oscillation (ENSO) or the Pacific Decadal Oscillation (PDO). Variations in regional precipitation amounts could explain 22.6% of the monthly variations in the diurnal temperature range, but not the trend over the 1960–2004 time period. Copyright © 2008 Royal Meteorological Society
Role of predictors in downscaling surface temperature to river basin in India for IPCC SRES scenarios using support vector machine
Authors: Anandhi Aavudai , Srinivas V. V. , Kumar D. Nagesh , Nanjundiah Ravi S.
Published: June 2008

In this paper, downscaling models are developed using a support vector machine (SVM) for obtaining projections of monthly mean maximum and minimum temperatures (Tmax and Tmin) to river‐basin scale. The effectiveness of the model is demonstrated through application to downscale the predictands for the catchment of the Malaprabha reservoir in India, which is considered to be a climatically sensitive region. The probable predictor variables are extracted from (1) the National Centers for Environmental Prediction (NCEP) reanalysis dataset for the period 1978–2000, and (2) the simulations from the third‐generation Canadian Coupled Global Climate Model (CGCM3) for emission scenarios A1B, A2, B1 and COMMIT for the period 1978–2100. The predictor variables are classified into three groups, namely A, B and C. Large‐scale atmospheric variables such as air temperature, zonal and meridional wind velocities at 925 mb which are often used for downscaling temperature are considered as predictors in Group A. Surface flux variables such as latent heat (LH), sensible heat, shortwave radiation and longwave radiation fluxes, which control temperature of the Earth's surface are tried as plausible predictors in Group B. Group C comprises of all the predictor variables in both the Groups A and B. The scatter plots and cross‐correlations are used for verifying the reliability of the simulation of the predictor variables by the CGCM3 and to study the predictor‐predictand relationships. The impact of trend in predictor variables on downscaled temperature was studied. The predictor, air temperature at 925 mb showed an increasing trend, while the rest of the predictors showed no trend. The performance of the SVM models that are developed, one for each combination of predictor group, predictand, calibration period and location‐based stratification (land, land and ocean) of climate variables, was evaluated. In general, the models which use predictor variables pertaining to land surface improved the performance of SVM models for downscaling Tmax and Tmin. Copyright © 2008 Royal Meteorological Society
Fresh bone marrow introduction into porous scaffolds using a simple low‐pressure loading method for effective osteogenesis in a rabbit model
Authors: Yoshii Toshitaka , Sotome Shinichi , Torigoe Ichiro , Tsuchiya Akio , Maehara Hidetsugu , Ichinose Shizuko , Shinomiya Kenichi
Published: June 2008

Recent advances in tissue engineering techniques have allowed porous biomaterials to be combined with osteogenic cells for effective bone regeneration. We developed a simple low‐pressure cell‐loading method using only syringes and stopcocks, and examined the effect of this method on osteogenesis when applied to the combination of highly porous β‐tricalcium phosphate (β‐TCP) and fresh autologous bone marrow. Both block and granule β‐TCP scaffolds were used to prepare implants in three different ways: without bone marrow as a control, with bone marrow that was allowed to penetrate spontaneously under atmospheric pressure (AP group), and with bone marrow that was seeded under low pressure (ULP group). These implants were transplanted into rabbit intramuscular sites, and the samples were examined biologically and histologically. The penetration efficiency of the block implants after marrow introduction was significantly higher in the ULP group than in the AP group. In the transplanted block samples, alkaline phosphatase activity was significantly higher in the ULP group at 2 weeks after implantation, and significantly more newly formed bone was observed in the ULP group at both 5 and 10 weeks compared with the AP group. Similar results were observed even in the experiment using β‐TCP granules, which are smaller than the blocks and frequently used clinically. Because of its convenience and safety, this low‐pressure method might be a novel, effective treatment to promote osteogenesis with bone marrow in clinical bone reconstruction surgeries. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1–7, 2009
Mechanical overload decreases the thermal stability of collagen in an in vitro tensile overload tendon model
Authors: Willett Thomas L. , Labow Rosalind S. , Lee J. Michael
Published: June 2008

Musculoskeletal soft tissue injuries are very common, yet poorly understood. We investigated molecular‐level changes in collagen caused by tensile overload of bovine tail tendons in vitro. Previous investigators concluded that tensile tendon rupture resulted in collagen denaturation, but our study suggests otherwise. Based on contemporary collagen biophysics, we hypothesized that tensile overload would lead to reduced thermal stability without change in the nativity of the molecular conformation. The thermal behavior of collagen from tail tendons ruptured in vitro at two strain rates (0.01 s−1 and 10 s−1) was measured by differential scanning calorimetry (DSC). The 1,000‐fold difference in strain rate was used since molecular mechanisms that determine mechanical behavior are thought to be strain rate‐dependent. DSC revealed that the collagen in tensile overloaded tendons was less thermally stable by 3° to 5°C relative to undamaged controls and was not denatured since there was no change in enthalpy of denaturation. The decrease in thermal stability occurred throughout the overloaded regions, independent of rupture site, and was greater in specimens ruptured at the lower strain rate. The deformation mechanism apparently involves disruption of the lattice structure of the collagen fibrils and greatly increases the molecular freedom of the collagen molecules, leading to reduced thermal molecular stability and the previously reported increased proteolysis. This has important implications for understanding soft tissue injuries, disease etiology and treatment, and for developing tissue engineered products with improved durability. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Effect of intermittent cyclic preloads on the response of articular cartilage explants to an excessive level of unconfined compression
Authors: Wei Feng , Golenberg Nurit , Kepich Eugene T. , Haut Roger C.
Published: June 2008

Mechanical loading of articular cartilage can influence chondrocyte metabolism and lead to alterations in cartilage matrix composition. Most previous studies have focused on the effect of cyclic loading on cartilage mechanical properties and proteoglycan synthesis. However, the role of proteoglycans synthesized from cyclically loaded cartilage in response to an acute overload has not been elucidated. Therefore, we conducted studies where low intensity, intermittent cyclic loading was applied to chondral explants prior to an acute unconfined compression on the tissue. The chondral explants were randomly assigned to three groups: 7, 14, and 21 days of 10 cycles of 0.2 Hz sinusoidal loading at 0.5 MPa followed by an unloaded interval of 3,600 s. All explants were then taken to 25 MPa of unconfined compression. Biochemical assays were conducted to determine the tissue proteoglycan and hydroxyproline contents. The results showed cyclic preloading increased the proteoglycan content and mechanically stiffened the explants, making them more resistant to matrix damage and cell death under 25 MPa of unconfined compression up to 14 days. After 21 days of cyclic loading, however, the explants lost compressive stiffness and suffered more extensive damage in the unconfined compression test. This study investigated the role of cyclic loading in response of chondral explants to a potentially damaging, acute overload. In the long term, these types of studies may help understand the role of preconditioning of articular cartilage for in vitro or even in vivo studies of blunt force trauma to a joint. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
New bone formation by murine osteoprogenitor cells cultured on corticocancellous allograft bone
Authors: Nelson Ehren R. , Huang Zhinong , Ma Ting , Lindsey Derek , Jacobs Christopher , Smith Robert L. , Goodman Stuart B.
Published: June 2008

The gold standard for bone grafting in orthopedics is autograft, however autograft has a limited supply and is associated with significant morbidity at the harvest site. One alternative, allograft bone, provides an osteoconductive scaffold, is in less limited supply, and it does not require a harvest from the patient. However, allograft lacks both osteogenic cells and osteoinductive proteins that make autograft bone so advantageous. This study provides a model to investigate strategies for augmentation of corticocancellous allograft bone discs with bone marrow‐derived osteoprogenitor cells (OPCs) plus exogenous growth factors in vitro. In this model, allograft bone discs were created by cutting 1‐mm thick slices from the distal femur and proximal tibia of euthanized mice. The allografts were sterilized and scanned by micro‐computed tomography (µCT) to provide the pre‐culture graft volume and trabecular characteristics. The discs were then seeded with OPCs harvested from murine bone marrow. The seeded grafts were placed in organ culture until harvest, after which they were re‐scanned by µCT and the data compared to the corresponding pre‐culture data. In addition, bone morphogenetic protein‐7 (BMP‐7, also know as osteogenic protein‐1 or OP‐1), basic fibroblast growth factor (bFGF), and OP‐1 combined with bFGF were added on a daily basis to the cultures. After final µCT scanning, all grafts were sectioned and evaluated histologically after hematoxylin and eosin (H&E) staining. µCT scans of cultured allografts with cells at 3, 5, and 9 weeks showed a time‐dependent, statistically significant increase in bone volume. The trabecular thickness (Tb.Th.) of grafts, from both groups that were augmented with OP‐1, showed a statistically significant increase in trabecular thickness of allografts with OPCs. These data suggest that bone marrow‐derived OPCs adhere to, and produce, new bone on corticocancellous allograft in vitro. When exogenous OP‐1 is added to this model, an increase in the production of bone onto the corticocancellous allograft bone disc is seen. This model allows for the investigation of the effects of multiple growth factors, and other interventions, on OPCs seeded onto allograft bone in vitro. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
The effect of hyaluronic acid on IL‐1β‐induced chondrocyte apoptosis in a rat model of osteoarthritis
Authors: Zhou Pang‐Hu , Liu Shi‐Qing , Peng Hao
Published: June 2008

The purpose of this article was to study the effect of hyaluronic acid (HA) on chondrocyte apoptosis in a rat osteoarthritis in vitro model (exposure to IL‐1β) and explore its mechanism. A rat in vitro model of osteoarthritis (OA) was established using 10 ng/mL IL‐1β as a modulating and chondrocyte apoptosis inducing agent. Different doses of HA (10, 20, and 40 µg/mL) were added 1 h prior to the addition of IL‐1β to a monolayer culture of freshly isolated juvenile rat chondrocytes. The ratio of apoptotic cell death was surveyed by Annexin V‐FITC and propidium iodide double‐labeling FACS analysis. The mitochondrial membrane potential of chondrocytes was evaluated by rhodamine‐123 fluorescence. The mitochondrial function was evaluated through detecting the ATP production by a luciferase assay. The reverse transcription polymerase chain reaction (RT‐PCR) was performed to measure mRNA expression levels of inducible oxide synthase (iNOS). HA could inhibit IL‐1β‐induced chondrocyte apoptosis in our cell culture model system. It was showed that addition of HA to the medium was able in a dose‐dependent way to reduce the impairment of the mitochondrial membrane potential and to restore mitochondrial ATP production. This study shows that HA could suppress in a dose‐dependent way chondrocyte apoptosis in our IL‐1β‐induced osteoarthritis model. The suppression of inflammatory cytokine activity within the joint might be one important mechanism of the clinical action of intraarticular injection of HA in the treatment of OA. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
The effect of oxidative aging on the wear performance of highly crosslinked polyethylene knee inserts under conditions of severe malalignment
Authors: Hermida Juan C. , Fischler Andrew , Colwell Clifford W. , D'Lima Darryl D.
Published: June 2008

First‐generation crosslinked polyethylene developed for total hip arthroplasty has not gained wide acceptance for knee arthroplasty because of the increased potential for failure under high stresses and the increased risk for oxidative damage caused by free radicals. Sequentially crosslinked polyethylene (SQXL) is a second‐generation crosslinked polyethylene that is reported to reduce the level of free radicals and preserve mechanical properties. Three groups of ultrahigh molecular weight polyethylene inserts were wear tested after artificial aging as per ASTM F2003: gamma‐irradiated in air (GA‐aged), sequentially crosslinked (SQXL‐aged), and electron‐beam irradiated and remelted (EBeam‐aged). Inserts were tested in an AMTI knee wear simulator under malalignment conditions that were two standard deviations from the mean reported for computer‐navigated and conventionally aligned techniques. GA‐aged inserts delaminated by 500,000 cycles, and were severely damaged after 1 million cycles. None of the highly crosslinked inserts (SQXL‐aged or EBeam‐aged) delaminated or showed any signs of severe wear. Mean wear rate for GA‐aged inserts was 124.6 ± 49.4 mg/million cycles. Mean wear rates for SQXL‐aged and EBeam‐aged inserts were significantly lower (1.74 ± 0.3 and 4.72 ± 0.7, respectively). These results support the low levels of free radicals and preservation of mechanical properties reported in second‐generation crosslinked ultrahigh molecular weight polyethylene. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res, 2008
Effects of changing strategies of fracture fixation on immunologic changes and systemic complications after multiple trauma: Damage control orthopedic surgery
Authors: Pape Hans‐Christoph
Published: June 2008

In the treatment of polytrauma patients, multiple studies have shown how the timing and the type of the initial surgery of long bone fractures influence the incidence of systemic complications. Database analyses documented that unduly long surgical procedures undertaken early after trauma increase the risk of acute respiratory distress syndrom (ARDS), especially when femoral shaft fractures are stabilized. Animal research and prospective clinical studies also support the fact that the type of stabilization of a femoral shaft fracture may influence the systemic response to trauma. Reamed intramedullary reaming and nailing for a femoral shaft fracture is associated with an increased risk of pulmonary fat embolization from the medullary canal. This can result in pulmonary compromise if certain cofactors are also present. Modified reamers have been developed to reduce this side effect. The mediating effects are immunologic changes, varying according to the magnitude of the surgical procedure. Pro‐inflammatory markers (e.g., Interleukins) may be used to assess the inflammatory response to injury as well as the magnitude of surgery and the systemic impact induced by surgery. Serum levels of such markers can be used clinically to tailor the amount of surgery that is performed to the clinical condition of the patient. The potentially negative impact of excessive surgery in high‐risk patients can be avoided by using a new grading system for the assessment of the clinical status of the injured patient. Most recently, a large prospective randomized multicenter study has documented that this grading system is effective for identifying these borderline patients, and that in the borderline patient a staged surgical approach, such as temporary femoral stabilization with an external fixator, reduces the incidence of systemic complications. This work has changed the surgical management of multiply injured patients toward an approach that is tailored to the clinical condition of the patient, as indicated by well‐defined clinical parameters as well as objective measurements of serum cytokine levels. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1478–1484, 2008
The ruminal degradability of fibre explains part of the low nutritional value and reduced methanogenesis in highly tanniniferous tropical legumes
Authors: Tiemann Tassilo T , Lascano Carlos E , Kreuzer Michael , Hess Hans Dieter
Published: June 2008

BACKGROUND: Limited forage quality and low methanogenesis from fermentation of tropical shrub legumes is often attributed to high contents of condensed tannins (CTs), but characteristics of the fibre may be important, too. Using the rumen‐simulation technique an attempt was made to separate the influence of tannins and fibre on ruminal digestion and methanogenesis. Legumes with CTs (Calliandra calothyrsus, Flemingia macrophylla) and plants free of CTs (Vigna unguiculata, Brachiaria humidicola) were used. To separate effects, either CTs were inactivated using polyethylene glycol or purified fibres free of CTs were obtained. In experiment 1, legumes replaced one third of grass in the diet and urea was supplemented. In experiment 2, only purified fibres and casein were incubated.

RESULTS: Purified fibres had a different degradability (low in legumes with CTs). Lignin prevented mainly hemicellulose from being degraded while the extent of degradation of hemicellulose seemed to have determined methanogenesis. In the mixed diets these effects were small when the supply of N was sufficient. When CTs were inactivated, fibre degradation was still lower with Calliandra than with Vigna.

CONCLUSION: Properties of fibre, especially lignification, of CT‐rich plants help to explain the low feeding value of such forages, but CTs represent the over‐riding factor. Copyright © 2008 Society of Chemical Industry
Relative importance of texture properties in the sensory quality and acceptance of commercial crispy products
Authors: Jaworska Danuta , Hoffmann Monika
Published: June 2008

BACKGROUND: Understanding the textural properties of a food can be important for producers and marketers of crispy products. Relationships between texture, overall sensory quality (OSQ) and consumer acceptance of different products have been a field of interest for many authors. Despite this, results of research concerning the importance of texture remain inconclusive. The aim of this study was to evaluate the relationship between texture and other sensory attributes on an example of potato chips and their OSQ and consumer acceptance. To determine which attributes played a dominant role in the OSQ of chips, statistical correlations were calculated.

RESULTS: Among the 11 attributes analysed, three had a positive relationship with the OSQ. These were: fried potato odour (r = 0.487), fried potato flavour (r = 0.597) and crispness (r = 0.570). The negative relation was observed for off‐flavour notes (r = − 0.740; − 0.693). Among the texture attributes, also negative, but without a dominant influence on OSQ, were hardness and undesirable type of fragmentation.

CONCLUSION: Texture properties were found to be significantly correlated with OSQ as well as with consumer acceptance, but other attributes, especially those with negative sensory effects, determined OSQ of the products examined and are of crucial importance for consumer acceptance. Copyright © 2008 Society of Chemical Industry
Structure and Properties of PHA/Clay Nano‐Biocomposites Prepared by Melt Intercalation
Authors: Bordes Perrine , Pollet Eric , Bourbigot Serge , Avérous Luc
Published: June 2008

PHA‐based nano‐biocomposites have been prepared by melt intercalation. Two main PHAs, poly(hydroxybutyrate) and poly(hydroxybutyrate‐co‐hydroxyvalerate) have been studied. Structural characterizations were conducted by advanced techniques like SAXS and TEM. A recent method has determined the degree of clay intercalation and dispersion using solid‐state NMR. Well intercalated small tactoids (3–10 layers) homogeneously dispersed into the polymer are obtained when good PHA–clay affinity exists, i.e., with organo‐modified MMT. In the case of non‐modified MMT, microcomposites are evidenced. Crystallization, mechanical, and thermal properties have been correlated to the materials structures.

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Straightforward Determination of the Degree of N‐Acetylation of Chitosan by Means of First‐Derivative UV Spectrophotometry
Authors: da Silva Ricardo M. P. , Mano João F. , Reis Rui L.
Published: June 2008

First‐derivative UV spectrophotometry is shown to be a reliable method for the determination of the degree of N‐acetylation of chitosan samples. A mathematical expression is derived that allows to determine the DA directly from the mass concentration of a chitosan solution and the first derivative of its UV spectrum at 202 nm, thus eliminating the need for empiric correction curves for highly deacetylated samples. A procedure is proposed for the accurate mass determination of the hygroscopic chitosan. The proposed approach facilitates the routine determination of the DA, especially when using potent multiwell microplate readers, which allow hundreds of samples to be measured in just a few minutes.

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Effect of Glutaraldehyde Crosslinking Conditions on the Strength and Water Stability of Wheat Gluten Fibers
Authors: Reddy Narendra , Tan Yeanching , Li Ying , Yang Yiqi
Published: June 2008

Regenerated protein fibers from plant proteins including wheat gluten lack the mechanical properties and water stability desired for usual applications. Crosslinking has been used to improve the properties of regenerated proteins fibers. Although glutaraldehyde is commonly used to crosslink proteins, the effect of various crosslinking conditions on the properties of the materials has not been studied. In this work, a systematic study of glutaraldehyde crosslinking conditions of wheat gluten fibers is presented and shows that even low concentrations of glutaraldehyde (0.05%) can improve the strength and water stability of wheat gluten fibers.

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A Highly Selective, Colorimetric, and Fluorometric Multisignaling Chemosensor for Hg2+ Based on Poly(p‐phenyleneethynylene) Containing Benzo[2,1,3]thiadiazole
Authors: Liu Shu‐Juan , Fang Chun , Zhao Qiang , Fan Qu‐Li , Huang Wei
Published: June 2008

A novel colorimetric and fluorometric chemosensor for Hg2+ detection based on poly(p‐phenyleneethynylene) (PPE) containing benzo[2,1,3]thiadiazole (BDT) has been developed. A highly Hg2+‐selective fluorescence quenching property in conjunction with a visible colorimetric change from yellow to violet can be observed, which indicates that PPE‐BDT can serve as a sensitive ‘naked‐eye’ indicator for Hg2+.

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Porous Protein‐Based Nanoparticle Hydrogel for Protein Chips with Improved Sensitivity
Authors: Tanaka Hiroyuki , Isojima Tatsushi , Hanasaki Minako , Ifuku Yasuo , Takeuchi Hisao , Kawaguchi Haruma , Shiroya Toshifumi
Published: June 2008

We have discovered a novel method to prepare a protein‐based hydrogel, that is, a ‘three‐dimensional nanostructured protein hydrogel’ (3D NPH), which is composed of loosely inter‐connected protein–polymer hybrid nanoparticles. The 3D NPH can be easily prepared by spotting a protein/polymer mixture on a substrate. Surprisingly, gold nanoparticles carrying protein molecules easily diffuse into the 3D NPH through pores and spaces. We have shown that the protein chip made by our 3D NPH method has tremendously improved sensitivity in detecting protein–protein interactions compared with that by direct protein immobilization methods.

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Towards Multipotent Coatings: Chemical Vapor Deposition and Biofunctionalization of Carbonyl‐Substituted Copolymers
Authors: Elkasabi Yaseen , Yoshida Mutsumi , Nandivada Himabindu , Chen Hsien‐Yeh , Lahann Joerg
Published: June 2008

Future advances in designing bioactive materials, such as antithrombotic coatings for cardiovascular stents, will require widely applicable and robust methods of surface modification. In this paper, we report on the development of multifunctional polymer coatings made by chemical vapor deposition (CVD) copolymerization. Polymer coatings of various [2.2]paracyclophane derivatives were co‐deposited in controlled ratios and their chemical composition verified by FT‐IR and X‐ray photoelectron spectroscopy. Furthermore, preliminary biocompatibility of these coatings was assessed using human umbilical vein endothelial cells and 3T3 murine fibroblasts. The parallel immobilization of two different antithrombotic biomolecules onto a CVD‐based copolymer is also demonstrated by orthogonal immobilization strategies.

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Ultrasound‐Assisted Synthesis of Hybrid Vanadium Oxide/Polyaniline Nanowires
Authors: Malta Marcos , Silva Luiz Henrique , Galembeck André , Korn Mauro
Published: June 2008

A single‐step sonochemical procedure to synthesize hybrid vanadium oxide/polyaniline nanowires starting from crystalline V2O5 and aniline in aqueous medium is presented. The synthesis explores the effect of high power ultrasounds on heterogeneous solid–aqueous phases, which leads to 30 nm width wires of 5 to 10 µm in length. Monomer intercalation and oxidative polymerization within the inorganic matrix proceed simultaneously with morphological changes. The electronic conductivity of hybrid nanowires reaches 0.8 S · cm−1 at room temperature.

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Analysis of a particle method for the one‐dimensional Vlasov‐Maxwell system
Authors: Bostan Mihai
Published: June 2008

In this article we present a particle method for solving numerically the one‐dimensional Vlasov‐Maxwell equations. This method is based on the formulation by characteristics. We perform the error analysis and we investigate the properties of this scheme. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009