bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential gene expression in skeletal muscle cells after membrane depolarization
Authors: Juretić Nevenka , Urzúa Ulises , Munroe David J. , Jaimovich Enrique , Riveros Nora 
Published: December 2006

AbstractSkeletal muscle is a highly plastic tissue with a remarkable capacity to adapt itself to challenges imposed by contractile activity. Adaptive response, that include hypertrophy and activation of oxidative mechanisms have been associated with transient changes in transcriptional activity of specific genes. To define the set of genes regulated by a depolarizing stimulus, we used 22 K mouse oligonucleotide microarrays. Total RNA from C2C12 myotubes was obtained at 2, 4, 18, and 24 h after high K+ stimulation. cDNA from control and depolarized samples was labeled with cyanine 3 or 5 dyes prior to microarray hybridization. Loess normalization followed by statistical analysis resulted in 423 differentially expressed genes using an unadjusted P‐value ≤ 0.01 as cut off. Depolarization affects transcriptional activity of a limited number of genes, mainly associated with metabolism, cell communication and response to stress. A number of genes related to Ca2+ signaling pathways are induced at 4 h, reinforcing the potential role of Ca2+ in early steps of signal transduction that leads to gene expression. Significant changes in the expression of molecules involved in muscle cell structure were observed; K+‐depolarization increased Tnni1 and Acta1 mRNA levels in both differentiated C2C12 and rat skeletal muscle cells in primary culture. Of these two, depolarization induced slow Ca2+ transients appear to have a role only in the regulation of Tnni1 transcriptional activity. We suggest that depolarization induced expression of a small set of genes may underlie Ca2+ dependent plasticity of skeletal muscle cells. J. Cell. Physiol. 210: 819–830, 2007. © 2006 Wiley‐Liss, Inc.
An automated tracking system to measure the dynamic properties of vesicles in living cells
Authors: Ku Tien‐Chuan , Huang Yun‐Nih , Huang Chien‐Chang , Yang De‐Ming , Kao Lung‐Sen , Chiu Tai‐Yu , Hsieh Chung‐Fan , Wu Pei‐Yo , Tsai Yuh‐Show , Lin Chung‐Chih 
Published: December 2006

AbstractRecent technological improvements have made it possible to examine the dynamics of individual vesicles at a very high temporal and spatial resolution. Quantification of the dynamic properties of secretory vesicles is labor‐intensive and therefore it is crucial to develop software to automate the process of analyzing vesicle dynamics. Dual‐threshold and binary image conversion were applied to enhance images and define the areas of objects of interest that were to be tracked. The movements, changes in fluorescence intensity, and changes in the area of each tracked object were measured using a new software system named the Protein Tracking system (PTrack). Simulations revealed that the system accurately recognized tracked objects and measured their dynamic properties. Comparison of the results from tracking real time‐lapsed images manually with those automatically obtained using PTrack revealed similar patterns for changes in fluorescence intensity and a high accuracy (<89%). According to tracking results, PTrack can distinguish different vesicular organelles that are similar in shape, based on their unique dynamic properties. In conclusion, the novel tracking system, PTrack, should facilitate automated quantification of the dynamic properties of vesicles that are important when classifying vesicular protein locations. Microsc. Res. Tech. 2007. © 2006 Wiley‐Liss, Inc.
The composition of capital flows to South Africa
Authors: Ahmed Faisal , Arezki Rabah , Funke Norbert 
Published: December 2006

AbstractUnlike in most other emerging markets, capital flows to South Africa since the mid 1990s have been heavily biased toward portfolio flows. In this context, the objective of the paper is twofold: to identify the determinants of the level and composition of capital flows to emerging markets and to draw policy conclusions for South Africa. The empirical results suggest that further trade and capital control liberalisation would increase the share of FDI in South Africa. Additionally, a reduction in exchange rate volatility would affect the composition of capital flows in favour of FDI. Copyright © 2006 John Wiley & Sons, Ltd.
Morphological changes in pedal phalanges through ornithopod dinosaur evolution: A biomechanical approach
Authors: Moreno Karen , Carrano Matthew T. , Snyder Rebecca 
Published: December 2006

AbstractThe evolution of ornithopod dinosaurs provides a well‐documented example of the transition from digitigrady to subunguligrady. During this transition, the ornithopod pes was drastically altered from the plesiomorphic dinosaurian morphology (four digits, claw‐shaped unguals, strongly concavo‐convex joints, phalanges longer than wide, excavated collateral ligament fossae, presence of sagittal ridge, and prominent processes for the attachment of tendons) to a more derived condition (tridactyly, modification of the unguals into hooves, phalanges wider and thinner than long, lack of collateral ligament fossae, loss of sagittal ridge and tendon attachment processes, relatively flattened articular surfaces). These changes are particularly noteworthy given the overall conservatism in pedal morphology seen across Dinosauria. But what are the functional consequences of these specific morphological transitions? To study them, we examine a wide range of pedal morphologies in four non‐avian dinosaurs and two birds. Our analyses of the external morphology, two‐dimensional models (using Finite Element Analysis), and internal bone structure demonstrate that this evolutionary shift was accompanied by a loss of digit mobility and flexibility. In addition, pedal posture was modified to better align the pes with the main direction of the ground reaction force, thus becoming well suited to support high loads. These conclusions can be applied to other, parallel evolutionary changes (in both dinosaurs and mammals) that involved similar transitions to a subunguligrade posture. J. Morphol, 2006. © 2006 Wiley‐Liss, Inc.
Reproductive morphology of Brittanichthys axelrodi (Teleostei: Characidae), a miniature inseminating fish from South America
Authors: Javonillo Robert , Burns John R. , Weitzman Stanley H. 
Published: December 2006

AbstractLight and electron microscopy were used to investigate the morphology of reproductive characters in a characid fish, Brittanichthys axelrodi. Spermatozoa were found in ovaries of females, thereby confirming insemination in this species. Bony hooks can be found on the fourth unbranched ray and branched rays 1–4 of the anal fin and the unique sigmoidally‐curved ray of the caudal fin in mature males. Testes have three distinct regions: an anterior spermatogenic region, an aspermatogenic middle region lined with a simple squamous epithelium and used for storage of mature spermatozoa, and a posterior region of coiled chambers lined with a high simple cuboidal epithelium. The most posterior region appears to be instrumental in the formation and storage of spermatozeugmata, unencapsulated sperm packets. Thus far, this tripartite testis morphology is unique among characids. The mature spermatozoon has an elongate nucleus (∼5 μm in length). A striated rootlet originates at the anterior end of the distal centriole and continues to the anterior tip of the cell. The striated rootlet wraps around the entire ventral area of the anterior part of the nucleus and appears to continue around the anterior tip of the nucleus and down the dorsal side as electron‐dense material. Several large, spherical mitochondria (∼0.6 μm in diameter) with lamellar cristae overlap the posterior end of the nucleus and continue beyond together with the cytoplasmic collar that contains the flagellum which lacks axonemal fins. Each spermatozeugma is lanceolate in shape when sectioned mid‐sagitally, with the core staining positively for mucopolysaccharides. In both sexes, the gonopore opens posterior to the anus, with the urinary pore having a separate opening posterior to the gonopore. Bands of skeletal muscle were found in the area of the male gonopore. These morphological features are likely linked to the reproductive mode of insemination, a trait that is so far as known, relatively rare among teleost fishes, but is proving increasingly frequent among certain groups of characid fishes. J. Morphol, 2006. © 2006 Wiley‐Liss, Inc.
Direct laser desorption/ionization time‐of‐flight mass spectrometry of conjugated polymers
Authors: Ma Zhun , Qiang Liang‐Liang , Fan Qu‐Li , Wang Yan‐Yan , Pu Kan‐Yi , Yin Rong , Huang Wei 
Published: December 2006

AbstractTwo conjugated polymers (CPs), poly(9,9‐dioctylfluorene) (PF) and poly(3‐octylthiophene) (PT) were analyzed by direct laser desorption/ionization time‐of‐flight mass spectrometry (LDI‐ToF MS). Because of their strong absorption near the wavelength of the laser (337 nm), easy and transient energy transfer properties and sufficient thermal stability, CPs can be desorbed and ionized directly without a matrix. For comparison, these two polymers were also analyzed using matrix‐assisted laser desorption/ionization (MALDI)‐ToF MS in the positive reflectron mode. The results revealed that they are very similar in terms of quality and resolution. All results demonstrate that LDI‐ToF MS is an alternative method for the mass characterization of some conjugated systems, thereby simplifying the process of sample preparation and result analysis. Copyright © 2006 John Wiley & Sons, Ltd.
Detection and identification of arginine modifications on methylglyoxal‐modified ribonuclease by mass spectrometric analysis
Authors: Brock Jonathan W. C. , Cotham William E. , Thorpe Suzanne R. , Baynes John W , Ames Jennifer M. 
Published: December 2006

AbstractAnalysis of the broad range of trace chemical modifications of proteins in biological samples is a significant challenge for modern mass spectrometry. Modification at lysine and arginine residues, in particular, causes resistance to digestion by trypsin, producing large tryptic peptides that are not readily sequenced by mass spectrometry. In this work, we describe the analysis of ribonuclease (RNase) modified by methylglyoxal (MGO) under physiological conditions. For detection of modifications, we use comparative analysis of the single combined spectra extracted from the full‐scan MS data of the tryptic digests from native and modified proteins. This approach revealed 11 ions unique to MGO‐modified RNase, including a 32‐amino acid peptide containing a modified Arg‐85 residue. Sequential digestion of MGO‐modified RNase by endoproteinase Glu‐C and trypsin was required to obtain peptides that were amenable to sequencing analysis. Arg‐39 was identified as the main site of modification (35% modification) on MGO‐modified Rnase, and the dihydroxyimidazolidine and hydroimidazolone derivatives were the main adducts formed, with minor amounts of the tetrahydropyrimidine and argpyrimidine derivatives. For identification of these products, we used variations in source voltage and collision energy to obtain the dehydration and decarboxylation products of the tetrahydropyrimidine‐containing peptides and dehydration of the dihydroxyimidazoline‐containing peptides. The resultant spectra were dependent on the cone voltage and collision energy, and analysis of spectra at various settings permitted structural assignments. These studies illustrate the usefulness of single combined mass spectra extracted from full‐scan data and variations in source and collision cell voltages for detection and structural characterization of chemical adducts on proteins. Copyright © 2006 John Wiley & Sons, Ltd.
Simulated changes in active/break spells during the Indian summer monsoon due to enhanced CO2 concentrations: assessment from selected coupled atmosphere–ocean global climate models
Authors: Mandke Sujata K. , Sahai A. K. , Shinde M. A. , Joseph Susmitha , Chattopadhyay R. 
Published: December 2006

AbstractThe simulations by ten coupled GCMs under the Intergovernmental Panel on Climate Change Assessment Report‐4 are used to study the implication of possible global climate change on active/break spells of the Indian summer monsoon (ISM). The validation of the mean daily cycle of the summer monsoon precipitation over the Indian core region and the spatial pattern of the ISM precipitation climatology with observation suggest that six models simulate fairly well, whereas four models differ from observation. Thus, the identification of active/break spells is confined to six models.The sensitivity to climate change has been assessed from two experiments, namely, 1% per year CO2 increase to doubling and 1% per year CO2 increase to quadrupling. The changes in the daily mean cycle and the standard deviation of precipitation, frequency, and duration of active/break spells in future climate change are uncertain among the models and at times among two experiments. The break composite precipitation anomalies strengthen and spread moderately (significantly) in the doubled (quadrupled) CO2 experiment. Copyright © 2006 Royal Meteorological Society
Simulation of seasonal precipitation and raindays over Greece: a statistical downscaling technique based on artificial neural networks (ANNs)
Authors: Tolika K. , Maheras P. , Vafiadis M. , Flocas H. A. , Arseni‐Papadimitriou A. 
Published: December 2006

AbstractA statistical downscaling technique based on artificial neural network (ANN) was employed for the estimation of local changes on seasonal (winter, spring) precipitation and raindays for selected stations over Greece. Empirical transfer functions were derived between large‐scale predictors from the NCEP/NCAR reanalysis and local rainfall parameters. Two sets of predictors were used: (1) the circulation‐based 500 hPa and (2) its combination along with surface specific humidity and raw precipitation data (nonconventional predictor). The simulated time series were evaluated against observational data and the downscaling model was found efficient in generating winter and spring precipitation and raindays. The temporal evolution of the estimated variables was well captured, for both seasons. Generally, the use of the nonconventional predictors are attributed to the improvement of the simulated results. Subsequently, the present day and future changes on precipitation conditions were examined using large‐scale data from the atmospheric general circulation model HadAM3P to the statistical model. The downscaled climate change signal for both precipitation and raindays, partly for winter and especially for spring, is similar to the signal from the HadAM3P direct output: a decrease of the parameters is predicted over the study area. However, the amplitude of the changes was different. Copyright © 2006 Royal Meteorological Society
The use of the alkane technique to estimate diet selection of sheep grazing grass–clover/heather–gorse vegetation communities
Authors: Ferreira Luis MM , Oliván Mamen , Celaya Rafael , Garcia Urce , Rodrigues Miguel AM , Osoro Koldo 
Published: December 2006

AbstractThe n‐alkane technique was evaluated for estimating the diet composition of sheep grazing in heathlands. Six dietary treatments, composed by different proportions of herbaceous (Lolium perenne and Trifolium repens) and woody species (Erica umbellata, Erica cinerea, Calluna vulgaris and Ulex gallii) were offered to 24 sheep housed in metabolism crates. Diet composition was estimated from alkane concentrations in diet and faeces, by least‐squares procedures, using all available alkanes (C1) from C25 to C33, or only those with higher concentration (C2): C27, C29, C30, C31 and C33. Additionally, the effect of applying mean treatment faecal recoveries (R1), mean faecal recoveries of all experimental diets (R2) or no faecal recovery correction (R3) was studied in both selections of alkanes (C1 and C2). No significant differences were observed between the use of all alkane information (C1) or limited number of alkanes (C2) in the diet composition calculations. There were no significant differences between measured proportions of dietary components and those estimated with procedures R1 and R2. In contrast, the proportions calculated with R3 procedure differed significantly (P < 0.05) from the measured proportions, overestimating feeds with higher content of long chain n‐alkanes. The results indicate that correction of faecal alkane concentrations to allow for incomplete faecal recovery is necessary in order to obtain accurate estimates of diet composition, using mean treatment faecal recoveries (R1) or mean faecal recoveries of all experimental diets (R2). Copyright © 2006 Society of Chemical Industry
Degradation of malathion in aqueous extracts obtained from different developmental stages of asparagus (Asparagus officinalis)
Authors: Talebi Khalil , Shibamoto Takayuki 
Published: December 2006

AbstractWhen malathion was incubated in aqueous extracts obtained from 17 vegetables and fruits at pH 7.4 and 37 °C for 4 h, asparagus extract exhibited the highest malathion degradation. The degradation effects of the extracts ranged from 100% (asparagus) to 0.5% (papaya). The highest malathion‐degradation effects obtained from extracts of asparagus at different growing stages incubated at pH 7.4 and 37 °C for 1 h was 94.4 ± 0.45% (stem length, 5–10 cm), followed by 88.0 ± 0.31% (10–15 cm), 85.1 ± 0.94 (15–20 cm), 82.2 ± 0.52 (20–25 cm), 81.2 ± 1.4% (pre‐emergent), 67.3 ± 0.67% (>25 cm), and 42.7 ± 2.1% (fern). The protein content in an asparagus extract from different growing stages was not consistent with the degradation activity of malathion. Results of time course studies on malathion degradation in asparagus extracts from different growing stages yielded half‐life times of malathion degradation ranging from 51.7 min (fern stage) to 17.3 min (stem length, 5–10 cm). Formation of α‐ and β‐malathion mono acids from malathion was detected in an incubated sample by gas chromatography/mass spectrometry. The results support the presence of carboxylesterases in asparagus extracts. Copyright © 2006 Society of Chemical Industry
Global existence and uniform stability of solutions for a quasilinear viscoelastic problem
Authors: Messaoudi Salim A. , Tatar Nasser‐eddine 
Published: December 2006

AbstractIn this paper the nonlinear viscoelastic wave equation in canonical form
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with Dirichlet boundary condition is considered. By introducing a new functional and using the potential well method, we show that the damping induced by the viscoelastic term is enough to ensure global existence and uniform decay of solutions provided that the initial data are in some stable set. Copyright © 2006 John Wiley & Sons, Ltd.
Well‐posedness, smooth dependence and centre manifold reduction for a semilinear hyperbolic system from laser dynamics
Authors: Lichtner Mark , Radziunas Mindaugas , Recke Lutz 
Published: December 2006

AbstractWe prove existence, uniqueness, regularity and smooth dependence of the weak solution on the initial data for a semilinear, first order, dissipative hyperbolic system with discontinuous coefficients. Such hyperbolic systems have successfully been used to model the dynamics of distributed feedback multisection semiconductor lasers. We show that in a function space of continuous functions the weak solutions generate a smooth skew product semiflow. Using slow fast structure and dissipativity we prove the existence of smooth exponentially attracting invariant centre manifolds for the non‐autonomous model. Copyright © 2006 John Wiley & Sons, Ltd.
3D‐based hp‐adaptive first‐order shell finite element for modelling and analysis of complex structures—Part 2: Application to structural analysis
Authors: Zboiński G. 
Published: December 2006

AbstractThe paper presents a 3D‐based adaptive first‐order shell finite element to be applied to hierarchical modelling and adaptive analysis of complex structures. The main feature of the element is that it is equipped with 3D degrees of freedom, while its mechanical model corresponds to classical first‐order shell theory. Other useful features of the element are its modelling and adaptive capabilities. The element is assigned to hierarchical modelling and hpq‐adaptive analysis of shell parts of complex structures consisting of solid, thick‐ and thin‐shell parts, as well as of transition zones, where h, p and q denote the mesh density parameter and the longitudinal and transverse orders of approximation, respectively. The proposed hp‐adaptive first‐order shell element can be joined with 3D‐based hpq‐adaptive hierarchical shell elements or 3D hpp‐adaptive solid elements by means of the family of 3D‐based hpq/hp‐ or hpp/hp‐adaptive transition elements.The main objective of the first part of our research, presented in the first part of the paper, was to provide non‐standard information on the original parts of the element algorithm. Here we describe the second part of the research, devoted to the methodology and results of the application of the element to various plate and shell problems. The main objective of this part is to verify algorithms of the element and to show its usefulness in modelling and adaptive analysis of shell and plate parts of complex structures. In order to do that, there is a presentation of the results of a comparative analysis of model plate and shell problems using the classical and our elements, and equidistributed and integrated Legendre shape functions. For the plate problem a comparison of the results obtained from the adaptive and non‐adaptive analysis is also included. Additionally, some advantages of the application of our element are shown through a comparative analysis of p‐convergence of the thin plate problem and an adaptive analysis of the exemplary complex structure. Copyright © 2006 John Wiley & Sons, Ltd.
Quantitative structural damage detection using high‐frequency piezoelectric signatures via the reverberation matrix method
Authors: Yan W. , Chen W. Q. , Cai J. B. , Lim C. W. 
Published: December 2006

AbstractHigh‐frequency structural analysis so far has been a major issue in dynamic analysis, for which many conventional methods such as finite element method and transfer matrix method are unable to perform well. Since the electromechanical impedance technique for structural health monitoring (SHM) operates at very high frequencies, the reverberation matrix method (RMM), which was just developed a few years ago, is employed to study dynamics of the monitored structures, which are bonded with piezoelectric lead zirconate titanate (PZT) patches. A piecewisely homogeneous Euler–Bernoulli beam model is introduced to approximate the non‐homogeneous beam and only one‐dimensional axial vibration of PZT wafers is considered. The imperfect interfacial bonding between PZT patches and the host beam is investigated based on a shear lag model. Using a hybrid technique combining electromechanical impedance method and RMM, an analytical expression of impedance (or admittance) related to the response of the coupled model of PZT patch‐bonding layer‐host beam system is derived for SHM. The proposed method is examined by comparing with other theoretical methods as well as by means of a test on an intelligent system using a steel beam with two symmetrically installed PZT wafers. It could be further applied to predicting the dynamics of monitored Timoshenko beams, continuous beams, and framed structures as well. Copyright © 2006 John Wiley & Sons, Ltd.