bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adaptation of the properties of spastic muscle with wrist extension deformity
Authors: Smeulders Mark J.C. , Kreulen Michiel 
Published: April 2006

AbstractTo show that human muscle may adapt to tendon transfer, adaptation of flexor carpi ulnaris (FCU) function was studied by measuring active and passive length–force characteristics at initial operation and at reoperation in a case of extension deformity secondary to FCU tendon transfer. At reoperation, FCU was 20 mm shorter; active force decreased ∼10%, indicating atrophy; and passive force increased, reflecting increased stiffness. FCU fiber length was unchanged. The presented case shows that human forearm muscle may adapt to a transferred function. Muscle Nerve, 2006
Carpal tunnel syndrome in older adults
Authors: Blumenthal Scott , Herskovitz Steven , Verghese Joe 
Published: April 2006

AbstractThe clinical and electrophysiologic characteristics of carpal tunnel syndrome (CTS) in elderly adults are not well established. We examined age differences in clinical, functional, and electrophysiologic features in elderly adults referred to a neuromuscular service for evaluation of symptoms suggestive of CTS. Of 415 consecutive subjects referred over an 18‐month period, 343 met clinical criteria for CTS. There were 158 young (≤50 years), 115 middle‐aged (51–64 years), and 70 elderly adults (≥65 years). There were no age differences in the duration of CTS symptoms, hand function, or presence of autonomic symptoms. The elderly adults had a higher prevalence of thenar weakness and thenar atrophy than younger subjects. Electrophysiologic abnormalities were more common and more severe in the older subjects. Our study shows that although there are no age differences in subjective complaints of CTS, older adults had objective clinical and electrophysiologic evidence of a more severe median nerve entrapment. The findings suggest that greater attention needs to be paid to objective evidence of CTS severity rather than subjective complaints when evaluating elderly adults presenting for clinical evaluation of CTS. Muscle Nerve, 2006
Upstream motions in stratified flow
Authors: Castro I. P. , Snyder W. H. 
Published: April 2006

In this paper experimental measurements of the time-dependent velocity and density perturbations upstream of obstacles towed through linearly stratified fluid are presented. Attention is concentrated on two-dimensional obstacles which generate turbulent separated wakes at Froude numbers, based on velocity and body height, of less than 0.5. The form of the upstream columnar modes is shown to be largely that of first-order unattenuating disturbances, which have little resemblance to the perturbations described by small-obstacle-height theories. For two-dimensional obstacles the disturbances are similar to those found by Wei, Kao & Pao (1975) and it is shown that provided a suitable obstacle drag coefficient is specified, the lowest-order modes (at least) are quantitatively consistent with the results of the Oseen inviscid model.Discussion of some results of similar measurements upstream of three-dimensional obstacles, the importance of towing tank endwalls and the relevance of the Foster & Saffman (1970) theory for the limit of zero Froude number is also included.
Numerical modelling of nonlinear effects in laminar flow through a porous medium
Authors: Coulaud O. , Morel P. , Caltagirone J. P. 
Published: April 2006

This paper deals with the introduction of a nonlinear term into Darcy's equation to describe inertial effects in a porous medium. The method chosen is the numerical resolution of flow equations at a pore scale. The medium is modelled by cylinders of either equal or unequal diameters arranged in a regular pattern with a square or triangular base. For a given flow through this medium the pressure drop is evaluated numerically.The Navier-Stokes equations are discretized by the mixed finite-element method. The numerical solution is based on operator-splitting methods whose purpose is to separate the difficulties due to the nonlinear operator in the equation of motion and the necessity of taking into account the continuity equation. The associated Stokes problems are solved by a mixed formulation proposed by Glowinski & Pironneau.For Reynolds numbers lower than 1, the relationship between the global pressure gradient and the filtration velocity is linear as predicted by Darcy's law. For higher values of the Reynolds number the pressure drop is influenced by inertial effects which can be interpreted by the addition of a quadratic term in Darcy's law.On the one hand this study confirms the presence of a nonlinear term in the motion equation as experimentally predicted by several authors, and on the other hand analyses the fluid behaviour in simple media. In addition to the detailed numerical solutions, an estimation of the hydrodynamical constants in the Forchheimer equation is given in terms of porosity and the geometrical characteristics of the models studied.
Ordered motion in the turbulent boundary layer over wind waves
Authors: Kawamura H. , Toba Y. 
Published: April 2006

The turbulent boundary layer over young wind waves (C/u* ∼ 1, where C is the phase speed of wind waves and u* is the friction velocity) has been investigated in a laboratory tank. Ordered motions have been found, and their structures studied in detail. Visualization of the outer boundary layer (0.4δ–1δ, where δ is the boundary-layer thickness) by paraffin mist has demonstrated the existence of a train of large-scale ordered motions having a horizontal lengthscale that corresponds to the wavelength of the underlying wind waves. Hot-wire measurements combined with the visualization have shown that the passage of the outer boundary-layer bulge is related to the occurrence of a low-speed air mass, usually accompanied by an upward velocity to produce large Reynolds stress. In the vicinity of the wave surface (0–0.15δ), flow separation occurs over these wind waves. Instantaneous velocity shear measurements, using two hot wires 0.15 cm apart vertically, have detected a high-shear layer at the edge of the separation bubbles. This high-shear layer, the potential site for generating much turbulence, reattaches on the windward side of the preceding wind waves. A pressure rise and a shear-stress spike, expected near the reattachment region, could be the mechanisms for supplying energy to the wind waves.The bursting phenomena over wind waves have been examined in detail in the logarithmic boundary layer (0.15δ–0.3δ). The bursting phenomena are a major mechanism for producing Reynolds stress and have a specific relationship with the phase of the wind wave. To explain the bursting phenomena, two mechanisms (not present in the boundary layer over a flat plate) are proposed, involving air-flow separation and the large-scale ordered motions, respectively. The two mechanisms are a ‘big burst’ related to the discharge of a whole separation bubble, and a ‘small burst’ which is the upward bursting of a low-speed air mass from the unstable separated shear layer into the ordered motions passing over a separation bubble.
Does soil determine the boundaries of monodominant rain forest with adjacent mixed rain forest and maquis on ultramafic soils in New Caledonia?
Authors: Read J. , Jaffré T. , Ferris J.M. , McCoy S. , Hope G. S. 
Published: April 2006

AbstractAim  To determine the soil characteristics of Nothofagus‐dominated rain forests in an ultramafic region (i.e. soils having high concentrations of metals including Mg, Fe and Ni), and whether soil characteristics may explain the location of monodominant rain forest in relation to adjacent mixed rain forest and maquis (shrub‐dominated vegetation).Location  New Caledonia.Methods  Soil characteristics were compared among six Nothofagus‐dominated rain forests from a range of altitudes and topographic positions. At four of these sites, comparisons were made with soils of adjacent mixed rain forest and maquis.Results  Soil characteristics varied among the monodominant Nothofagus forests, largely due to differences between ultramafic soils and soils influenced by non‐ultramafic intrusions. The soils of all vegetation types had low concentrations of nutrients, particularly P, K and Ca (both total and extractable/exchangeable), and high total concentrations of Ni, Fe, Cr and Mn. There were significant differences between the rain forests and adjacent maquis in soil concentrations of several elements (N, P, Ca, Mg and Mn), more so in surface soils than at depth, but much of this pattern may be caused by effects of vegetation on the soil, rather than of soil on the vegetation. However, there were no significant differences in soil concentrations of any mineral elements between Nothofagus forest and adjacent mixed rain forest.Main conclusions  We found no evidence for soil mediation of boundaries of Nothofagus rain forest with mixed rain forest, and little evidence for the boundaries of either forest type with maquis. We suggest that the local abrupt boundaries of these monodominant Nothofagus forests are directly related to temporal factors, such as time since the last wildfire and frequency of wildfire, and that disturbance is therefore a major causal factor in the occurrence of these forests.
Stem CO2 release under illumination: corticular photosynthesis, photorespiration or inhibition of mitochondrial respiration?
Authors: WITTMANN CHRISTIANE , PFANZ HARDY , LORETO FRANCESCO , CENTRITTO MAURO , PIETRINI FABRIZIO , ALESSIO GIORGIO 
Published: April 2006

ABSTRACTIn illuminated stems and branches, CO2 release is often reduced. Many light‐triggered processes are thought to contribute to this reduction, namely photorespiration, corticular photosynthesis or even an inhibition of mitochondrial respiration. In this study, we investigated these processes with the objective to discriminate their influence to the overall reduction of branch CO2 release in the light. CO2 gas‐exchange measurements of young birch (Betula pendula Roth.) branches (< 1.5 cm) performed under photorespiratory (20% O2) and non‐photorespiratory (< 2%) conditions revealed that photorespiration does not play a pre‐dominant role in carbon exchange. This suppression of photorespiration was attributed to the high CO2 concentrations (Ci) within the bark tissues (1544 ± 227 and 618 ± 43 µmol CO2 mol−1 in the dark and in the light, respectively). Changes in xylem CO2 were not likely to explain the observed decrease in stem CO2 release as gas‐exchange measurements before and after cutting of the branches did not effect CO2 efflux to the atmosphere. Combined fluorescence and gas‐exchange measurements provided evidence that the light‐dependent reduction in CO2 release can pre‐dominantly be attributed to corticular refixation, whereas an inhibition of mitochondrial respiration in the light is unlikely to occur. Corticular photosynthesis was able to refix up to 97% of the CO2 produced by branch respiration, although it rarely led to a positive net photosynthetic rate.
Expression of tobacco ethylene receptor NTHK1 alters plant responses to salt stress
Authors: CAO WAN‐HONG , LIU JUN , ZHOU QI‐YUN , CAO YANG‐RONG , ZHENG SHU‐FANG , DU BAO‐XING , ZHANG JIN‐SONG , CHEN SHOU‐YI 
Published: April 2006

ABSTRACTEthylene has been regarded as a stress hormone involved in many stress responses. However, ethylene receptors have not been studied for the roles they played under salt stress condition. Previously, we characterized an ethylene receptor gene NTHK1 from tobacco, and found that NTHK1 is salt‐inducible. Here, we report a further investigation towards the function of NTHK1 in response to salt stress by using a transgenic approach. We found that NTHK1 promotes leaf growth in the transgenic tobacco seedlings but affects salt sensitivity in these transgenic seedlings under salt stress condition. Differential Na+/K+ ratio was observed in the control Xanthi and NTHK1‐transgenic plants after salt stress treatment. We further found that the NTHK1 transgene is also salt‐inducible in the transgenic plants, and the higher NTHK1 expression results in early inductions of the ACC (1‐aminocyclopropane‐1‐carboxylic acid) oxidase gene NtACO3 and ethylene responsive factor (ERF) genes NtERF1 and NtERF4 under salt stress. However, NTHK1 suppresses the salt‐inducible expression of the ACC synthase gene NtACS1. These results indicate that NTHK1 regulates salt stress responses by affecting ion accumulation and related gene expressions, and hence have significance in elucidation of ethylene receptor functions during stress signal transduction.
Steatosis in chronic hepatitis C: Relationship to the virus and host risk factors
Authors: Matos Carla AL , Perez Renata M , Pacheco Mauricio S , Figueiredo‐Mendes Claudio G , Lopes‐Neto Edmundo , Oliveira Evandro B , Lanzoni Valeria P , Silva Antonio EB , Ferraz Maria LG 
Published: April 2006

AbstractBackground:  Steatosis occurs frequently in hepatitis C. However, the mechanisms leading to this lesion are still unknown, and the role of steatosis in the progression of the disease remains controversial. The aim of the present paper was to determine the prevalence of steatosis in hepatitis C and its association with hepatitis C virus (HCV) genotype, viral load and the presence of risk factors for steatosis, and to analyze the association between steatosis and the intensity of liver disease.Methods:  Patients infected with HCV who underwent liver biopsy were included. Patients coinfected with hepatitis B virus and/or human immunodeficiency virus and those previously treated for hepatitis C were excluded. The following risk factors for steatosis were investigated: obesity (body mass index [BMI] > 25 kg/m2), diabetes mellitus, hyperlipidemia, alcoholism, and use of potential steatosis‐inducing drugs. Histological analysis evaluated the presence of steatosis, the degree of periportal activity and staging. Patients with and without steatosis were compared regarding demographic, epidemiological, laboratory and histological characteristics. Logistic regression analysis was applied to identify variables that were independently associated with the presence of steatosis.Results:  Ninety patients (55 men, 35 women) with a mean age of 45 ± 13 years were included. The prevalence of steatosis was 67%. Variables that remained independently associated with steatosis were age, female gender, obesity and genotype 3.Conclusions:  The prevalence of steatosis in hepatitis C was high. Risk factors usually related to steatosis such as age, female gender and obesity, as well as genotype 3, were independently associated with the presence of steatosis. Steatosis was not independently associated with the intensity of histological liver disease.
Comparative immunohistochemical expression of p63 in human cholangiocarcinoma and hepatocellular carcinoma
Authors: Ramalho Fernando S , Ramalho Leandra NZ , Della Porta Livia , Zucoloto Sérgio 
Published: April 2006

AbstractBackground:  p63 helps regulate differentiation and proliferation in epithelial progenitor cells. Its expression is often higher in malignant tissue compared with normal tissue, and poorly differentiated carcinomas often show a larger number of p63‐positive cells than well‐differentiated tumors. The aim of the present study was to investigate the immunohistochemical expression of p63 in human cholangiocarcinomas (CC) and hepatocellular carcinomas (HCC).Methods:  Sixteen cases of CC and 37 cases of HCC were selected for the present study. Paraffin‐embedded sections were submitted to immunohistochemical double‐staining to identify p63 and cytokeratin 19.Results:  p63 was diffusely expressed in 100% of CC, while it was negative in all HCC. In addition, cytokeratin 19, a marker for hepatic progenitor cells, was colocalized in all p63‐positive cells.Conclusions:  The nuclear immunostaining for p63 in all CC cases indicates that the p63 protein can act to promote neoplastic growth in bile duct epithelium, but it is not important for hepatocellular carcinogenesis. Co‐localization of p63 and cytokeratin 19 in CC cells suggests that CC may be derived from undifferentiated progenitor cells (hepatic oval cells). Furthermore, p63 can be useful in the differential diagnosis between CC and HCC in biopsy samples.
A very low toxic agent induces apoptosis and reduces growth of human hepatocellular carcinoma cells
Authors: Schumacher Guido , Scheunert Sylvia , Rueggeberg Anne , Bachem Max G. , Nussler Andreas K. , Spinelli Antonino , Mukhopadhyay Tapas , Pratschke Johann , Neuhaus Peter 
Published: April 2006

AbstractAim:  To examine the efficacy on growth inhibition of 2‐methoxyestradiol (2‐ME) on human hepatocellular carcinoma in vitro.Methods:  Hep3B, SK‐Hep1, and PLC/PRF/5 cells were used. Proliferation assays using 2‐ME should show a dose‐dependent reduction of cell number. Different staining methods in cells derived from human hepatocellular carcinoma and normal human hepatocytes were performed to demonstrate possible tumor specific induction of apoptosis. FACS‐analysis was done to confirm the induction of apoptosis after treatment with 2‐ME.Results:  A reduction of the cell number of 90–98% was observed in all cancer cells after treatment with 2 µmol 2‐ME. The mechanism of action appeared to be induction of apoptosis. Normal human hepatocytes were unaffected by 2‐ME. The most sensitive cell line to 2‐ME, SK‐Hep1, showed an up‐regulation of the p53 and p21 proteins.Conclusions:  2‐Methoxyestradiol appears to be highly effective in reducing tumor growth in vitro in human hepatocellular carcinoma. It may be tumor specific and applicable for clinical trials.
Atopic eczema: what's new?
Authors: Möhrenschlager M , Darsow U , Schnopp C , Ring J 
Published: April 2006

AbstractAtopic eczema (AE) is a chronic inflammatory skin disease characterized by recurrent intense pruritus and a typical age‐related distribution of skin lesions. Several new aspects with regard to the pathogenetic background as well as strategies for prevention, diagnosis and treatment of AE have emerged. There are ongoing studies on genetic susceptibility loci, as well as environmental and nutritional factors associated with an increase or a decrease of AE lesions. The atopy patch test is now available for identification of allergens in aeroallergen‐triggered AE. New topical therapies, such as the calcineurin inhibitors, have broadened the therapeutic armamentarium substantially. In order to increase knowledge and coping strategies, patient education programs have been launched.Learning objective  Upon completing this paper, the reader should be aware of new developments in AE, especially on nomenclature, prevention strategies, diagnostic tests, as well as therapeutic options.
The statistics of identifying differentially expressed genes in Expresso and TM4: a comparison
Authors: Sioson Allan A , Mane Shrinivasrao P , Li Pinghua , Sha Wei , Heath Lenwood S , Bohnert Hans J , Grene Ruth 
Published: April 2006

AbstractBackgroundAnalysis of DNA microarray data takes as input spot intensity measurements from scanner software and returns differential expression of genes between two conditions, together with a statistical significance assessment. This process typically consists of two steps: data normalization and identification of differentially expressed genes through statistical analysis. The Expresso microarray experiment management system implements these steps with a two-stage, log-linear ANOVA mixed model technique, tailored to individual experimental designs. The complement of tools in TM4, on the other hand, is based on a number of preset design choices that limit its flexibility. In the TM4 microarray analysis suite, normalization, filter, and analysis methods form an analysis pipeline. TM4 computes integrated intensity values (IIV) from the average intensities and spot pixel counts returned by the scanner software as input to its normalization steps. By contrast, Expresso can use either IIV data or median intensity values (MIV). Here, we compare Expresso and TM4 analysis of two experiments and assess the results against qRT-PCR data.ResultsThe Expresso analysis using MIV data consistently identifies more genes as differentially expressed, when compared to Expresso analysis with IIV data. The typical TM4 normalization and filtering pipeline corrects systematic intensity-specific bias on a per microarray basis. Subsequent statistical analysis with Expresso or a TM4t-test can effectively identify differentially expressed genes. The best agreement with qRT-PCR data is obtained through the use of Expresso analysis and MIV data.ConclusionThe results of this research are of practical value to biologists who analyze microarray data sets. The TM4 normalization and filtering pipeline corrects microarray-specific systematic bias and complements the normalization stage in Expresso analysis. The results of Expresso using MIV data have the best agreement with qRT-PCR results. In one experiment, MIV is a better choice than IIV as input to data normalization and statistical analysis methods, as it yields as greater number of statistically significant differentially expressed genes; TM4 does not support the choice of MIV input data. Overall, the more flexible and extensive statistical models of Expresso achieve more accurate analytical results, when judged by the yardstick of qRT-PCR data, in the context of an experimental design of modest complexity.
A factor analysis model for functional genomics
Authors: Kustra Rafal , Shioda Romy , Zhu Mu 
Published: April 2006

AbstractBackgroundExpression array data are used to predict biological functions of uncharacterized genes by comparing their expression profiles to those of characterized genes. While biologically plausible, this is both statistically and computationally challenging. Typical approaches are computationally expensive and ignore correlations among expression profiles and functional categories.ResultsWe propose a factor analysis model (FAM) for functional genomics and give a two-step algorithm, using genome-wide expression data for yeast and a subset of Gene-Ontology Biological Process functional annotations. We show that the predictive performance of our method is comparable to the current best approach while our total computation time was faster by a factor of 4000. We discuss the unique challenges in performance evaluation of algorithms used for genome-wide functions genomics. Finally, we discuss extensions to our method that can incorporate the inherent correlation structure of the functional categories to further improve predictive performance.ConclusionOur factor analysis model is a computationally efficient technique for functional genomics and provides a clear and unified statistical framework with potential for incorporating important gene ontology information to improve predictions.