bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microindentation test for assessing the mechanical properties of cartilaginous tissues
Authors: Li Xiaodong , An Yuehuei H. , Wu Yii‐Der , Song Ying Ching , Chao Yuh J. , Chien Chi‐Hui 
Published: May 2006

AbstractMechanical properties of the fresh control, frozen, and vitrified cartilaginous (cartilage and meniscus) samples were measured by microindentation. Indentation depth, elastic modulus, and indentation yield strength were obtained from the microindentation loading curves. Indentation deformation behavior was studied using Hertz contact model. The stress distribution of cartilaginous tissues under indentation loading was analyzed by finite element technique. It was found that fresh tissue shows the lowest indentation depth and the highest elastic modulus and indentation yield strength, followed by vitrified and frozen tissues. The vitrified tissue shows slightly lower but comparable mechanical properties with control tissue. The vitrification technique used in this study can preserve live cells with superior mechanical properties that make it an ideal technique for use in orthopedic and other biomedical applications. The microindentation tests and corresponding analysis methods used in this study offer a simple way to evaluate the mechanical properties of cartilaginous tissues. It suits small sample sizes and it may be used for other biological tissues. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Calcium‐deficient apatite synthesized by ammonia hydrolysis of dicalcium phosphate dihydrate: Influence of temperature, time, and pressure
Authors: Obadia Laetitia , Rouillon Thierry , Bujoli Bruno , Daculsi Guy , Bouler Jean Michel 
Published: May 2006

AbstractIn this work, calcium‐deficient apatites (CDA) were synthesized by ammonia hydrolysis reaction of dicalcium phosphate dihydrate (DCPD; CaHPO4·2H2O) to obtain biphasic calcium phosphates (BCP) without any extraionic substitution. The influence of three parameters was studied: temperature of the reaction (70 and 100°C), time of the reaction (4 and 18 h), and the pressure (open and closed system). Experiments were made according to a factorial design method (FDM) allowing optimization of the number of samples as well as statistical analysis of results. Moreover, the influence of temperature (until 200°C) was investigated. The crystal size of CDA was determined according to the Scherrer's formula and from Rietveld refinements taking the CDA anisotropy into account. The last method seems to be a reliable method to determine crystallite sizes of CDA, since crystallite sizes of CDA along <00l> and <hk0> directions were accessible. The results describe the hydroxyapatite % (HA%) in BCP by a first‐order polynomial equation in the experimental area studied and the HA content was found to increase by raising time and temperature of the reaction. Moreover, the type of reaction system (open/closed vessel) appeared to have little influence on HA%. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Protein adsorption onto polyester surfaces: Is there a need for surface activation?
Authors: Atthoff Björn , Hilborn Jöns 
Published: May 2006

AbstractSurface hydrolysis of polyester scaffolds is a convenient technique suggested to promote protein adsorption for improving cell attachment. We have, therefore, investigated the effect of hydrolysis of polyester surfaces for protein adsorption to clarify the conditions needed. Three polyesters, poly(ethylene terephthalate) (PET), poly(lactic acid) (PLA), and poly(glycolic acid) (PGA), were selected. Adsorption was investigated by X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and quartz crystal microbalance (QCM). Hydrolyzed PET adsorbed significantly more proteins than nonhydrolyzed. Degradable polymers adsorbed at higher rates when the polymers were hydrolyzed prior to adsorption, but the same amount as nonhydrolyzed, suggesting spontaneous hydrolysis during the adsorption. XPS shows that hydrolysis prior to absorption for PET results in a surface nitrogen composition of ∼14%, similar to pure protein (16%). Nonhydrolyzed PET surfaces showed only ∼7% nitrogen, indicating protein layers thinner than ∼10 nm. Adsorption to PLA and PGA shows nitrogen contents of 14–15% in both cases. SEM revealed striking differences in morphology of the protein coating. Hydrolyzed or spontaneously hydrolyzable surfaces display a pronounced fibrous structure while nonhydrolyzed surfaces give smooth structures. In combination, the results show that surface hydrolysis increase adsorption rate, but not the amount of proteins on polyesters that degrades in vivo. Surface treatment of nondegradable polyester increases the total amount of proteins and induces the formation of fibrous protein structures. Post hydrolysis treatment by acetic acid, replacing the counter‐ion to a proton, further enhances protein attachment. Finally, cell attachment experiments verifies that protein adsorption increase the cell attachment to polyester surfaces. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Comparing the validity of multiple social effectiveness constructs in the prediction of managerial job performance
Authors: Semadar Assaf , Robins Garry , Ferris Gerald R. 
Published: May 2006

AbstractSocial effectiveness constructs have been receiving increased attention in organizational research. However, the proliferation of such constructs raises questions of their relative effectiveness as predictors of job performance when used in multivariate comparison. The current study examined four social effectiveness constructs (i.e., self‐monitoring, leadership self‐efficacy, emotional intelligence and political skill) in the prediction of managerial job performance. Bivariate correlations showed that performance was predicted by social effectiveness constructs with the exception of self‐monitoring. Multiple regression analyses, using gender and seniority as control variables, found political skill to be the strongest predictor and that it has significant incremental validity in the prediction of performance over the prediction provided by the other three social effectiveness constructs as a set. Strengths and limitations of the study are discussed, as are directions for future research. Copyright © 2006 John Wiley & Sons, Ltd.
Kinetic evidence for the copper peroxide intermediate with two copper ions in proximity
Authors: Selvarani S. , Medona B. , Ramachandran M. S. 
Published: May 2006

AbstractThe decomposition of caroate (peroxomonosulfate, PMS) is catalyzed by Cu(II) ions even at 5 × 10−5 M in aqueous alkaline solution. The rate is second order in copper(II) ions concentrations and first order in [PMS]. The rate constant values are found to decrease with increase in hydroxide ion concentrations. The turnover number for the reaction is estimated as >1000. The experimental results suggest that the formation of peroxide type intermediate with two copper(II) ions is the rate‐determining step. This peroxide intermediate reacts with another molecule of PMS to give the products oxygen, SO and copper ions. The overall entropy of activation is positive with a value of ∼20 cals/mol/K. The very high turnover number suggests that Cu(II) ion is one of the best catalysts for the decomposition of caroate ions in alkaline medium. The reaction also represents a system in which metal ion catalyzed decomposition of caroate does not involve radical intermediates. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 439–443, 2006
Gas‐phase chemistry of dihydromyrcenol with ozone and OH radical: Rate constants and products
Authors: Forester Crystal D. , Ham Jason E. , Wells J. R. 
Published: May 2006

AbstractA bimolecular rate constant, kOH + dihydromyrcenol, of (38 ± 9) × 10−12 cm3 molecule−1 s−1 was measured using the relative rate technique for the reaction of the hydroxyl radical (OH) with 2,6‐dimethyl‐7‐octen‐2‐ol (dihydromyrcenol,) at 297 ± 3 K and 1 atm total pressure. Additionally, an upper limit of the bimolecular rate constant, k, of approximately 2 × 10−18 cm3 molecule−1 s−1 was determined by monitoring the decrease in ozone (O3) concentration in an excess of dihydromyrcenol. To more clearly define part of dihydromyrcenol's indoor environment degradation mechanism, the products of the dihydromyrcenol + OH and dihydromyrcenol + O3 reactions were also investigated. The positively identified dihydromyrcenol/OH and dihydromyrcenol/O3 reaction products were acetone, 2‐methylpropanal (OCHCH(CH3)2), 2‐methylbutanal (OCHCH(CH3)CH2CH3), ethanedial (glyoxal, HC(O)C(O)H), 2‐oxopropanal (methylglyoxal, CH3C(O)C(O)H). The use of derivatizing agents O‐(2,3,4,5,6‐pentafluorobenzyl)hydroxylamine (PFBHA) and N,O‐bis(trimethylsilyl)trifluoroacetamide (BSTFA) clearly indicated that several other reaction products were formed. The elucidation of these other reaction products was facilitated by mass spectrometry of the derivatized reaction products coupled with plausible dihydromyrcenol/OH and dihydromyrcenol/O3 reaction mechanisms based on previously published volatile organic compound/OH and volatile organic compound/O3 gas‐phase reaction mechanisms. © 2006 Wiley Periodicals, Inc.*This article is a US Government work and, as such, is in the public domain of the United States of America
Int J Chem Kinet 38: 451–463, 2006
Array‐comparative genomic hybridization to detect genomewide changes in microdissected primary and metastatic oral squamous cell carcinomas
Authors: Liu Chung‐Ji , Lin Shu‐Chun , Chen Yann‐Jang , Chang Kuo‐Ming , Chang Kuo‐Wei 
Published: May 2006

AbstractOral squamous cell carcinoma (OSCC) is a common worldwide malignancy. However, it is unclear what, if any, genomic alterations occur as the disease progresses to invasive and metastatic OSCC. This study used genomewide array‐CGH in microdissected specimens to map genetic alterations found in primary OSCC and neck lymph node metastases. We used array‐based comparative genomic hybridization (array‐CGH) to screen genomewide alterations in eight pairs of microdissected tissue samples from primary and metastatic OSCC. In addition, 25 primary and metastatic OSCC tissue pairs were examined with immunohistochemistry for protein expression of the most frequently altered genes. The highest frequencies of gains were detected in LMYC, REL, TERC, PIK3CA, MYB, MDR1, HRAS, GARP, CCND2, FES, HER2, SIS, and SRY. The highest frequencies of losses were detected in p44S10, TIF1, LPL, MTAP, BMI1, EGR2, and MAP2K5. Genomic alterations in TGFβ2, cellular retinoid‐binding protein 1 gene (CRBP1), PIK3CA, HTR1B, HRAS, ERBB3, and STK6 differed significantly between primary OSCC and their metastatic counterparts. Genomic alterations in PRKCZ, ABL1, and FGF4 were significantly different in patients who died compared with those who survived. Immunohistochemistry confirmed high PIK3CA immunoreactivity in primary and metastatic OSCC. Higher FGF4 immunoreactivity in primary OSCC is associated with a worse prognosis. Loss of CRBP1 immunoreactivity is evident in primary and metastatic OSCC. Our study suggests that precise genomic profiling can be useful in determining gene number changes in OSCC. As our understanding of these changes grow, this profiling may become a practical tool for clinical evaluation. © 2006 Wiley‐Liss, Inc.
Dynamic expression of neurotrophic factor receptors in postnatal spinal motoneurons and in mouse model of ALS
Authors: Zhang Jiasheng , Huang Eric J. 
Published: May 2006

AbstractNeurotrophic factors support the survival of spinal motoneurons (MNs) and have been considered as strong candidates for treating motoneuron diseases. However, it is unclear if the right combination of neurotrophic factor receptors is present in postnatal spinal MNs. In this study, we show that the level of c‐ret expression remains relatively stable in embryonic and postnatal spinal MNs. In contrast, the mRNA and protein of GFRα1 and ‐2 are progressively down‐regulated in postnatal life. By 3 and 6 months of age, both receptors are barely detectable in spinal MNs. The down‐regulation of GFRα1 appears accelerated in transgenic mice expressing mutant SOD1G93A. Despite the progressive loss of GFRα1 and ‐2, phosphorylation of c‐ret shows no detectable reduction on tyrosine residues or on serine 696. In addition to the GFRα subunits, expression of TrkB also shows a dynamic change. During embryogenesis, there is twice as much full‐length TrkB as the truncated TrkB isoform. However, this ratio is reversed in postnatal spinal cord. Expression of the mutant SOD1G93A appears to have no effect on the TrkB receptor ratio. Taken together, our data indicate that the expression of neurotrophic factor receptors, GFRα1, ‐2, and TrkB, is not static, but undergoes dynamic changes in postnatal spinal MNs. These results provide insights into the use of neurotrophic factors as therapeutic agents for ALS. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006
Assignment of 1H NMR spectrum and investigation of oxidative degradation of poly(ethylenimine) using 1H and 13C 1‐D and 2‐D NMR
Authors: Idris Salah A , Mkhatresh Omar A , Heatley Frank 
Published: May 2006

AbstractThe 1H NMR spectrum of poly(ethylenimine) (PEI) has been assigned using two‐dimensional NMR correlation with the previously established assignment of the 13C spectrum. The oxidative thermal and UV degradation of PEI has been studied using mass loss measurements, and NMR and Fourier transform infrared spectroscopy. Analysis of the spectra of the degradation products shows that the degradation process may readily be monitored, particularly by 13C NMR. The major products are formamide and other amide groups which may be understood in terms of chain scission and dehydration reactions of hydroperoxides. Copyright © 2006 Society of Chemical Industry
The effect of area closures on the demersal fish community off the east coast of Iceland
Authors: Jaworski Andrzej , Solmundsson Jon , Ragnarsson Stefan Aki 
Published: May 2006

Abstract
The effect of reduced fishing effort on the demersal fish community, following area closures in 1993, was analysed for two protected areas off the east coast of Iceland, Digranesflak and Breiddalsgrunn. The data were collected using a standardized bottom trawl during groundfish surveys in the period 1985–2004. The aspects of the fish community that were analysed included abundance by size class, mean size, species richness, diversity, and composition. The analysis was conducted for closed areas and adjacent reference (fished) areas, as well as for periods before and after the closure (and also after the re-opening in Breiddalsgrunn), using an ANOVA model and planned comparisons. The closure had a favourable impact on abundance of haddock (Melanogrammus aeglefinus) and small long rough dab (Hippoglossoides platessoides) in Digranesflak, and on exploitable sizes of haddock and cod (Gadus morhua) in Breiddalsgrunn. The mean size of haddock increased considerably within the protected areas relative to the reference areas: by 16 cm in Digranesflak and by 10 cm in Breiddalsgrunn. Species richness, diversity, and composition varied over the study period and between areas, but no effect of area closure was found. The observed changes in the fish community in Breiddalsgrunn were reversed within 7 years of the re-opening of the area to fishing. The possible causes for the observed patterns of response to area closures are discussed.
How do Swedish paediatric clinics diagnose coeliac disease? Results of a nationwide questionnaire study
Authors: Stenhammar Lars , Högberg Lotta , Danielsson Lars , Ascher Henry , Dannaeus Anders , Hernell Olle , Ivarsson Anneli , Lindberg Eva , Lindquist Bo , Nivenius Kerstin 
Published: May 2006

Abstract Background and aim: Diagnosis of coeliac disease is based on the demonstration of enteropathy in a small bowel biopsy. Correct diagnosis is of utmost importance, since the need for dietary management is life long, and inadequate treatment may lead to potentially serious complications. The Swedish Working Group for Paediatric Coeliac Disease has published guidelines for the diagnosis of childhood coeliac disease. The present questionnaire was designed in order to create the basis for revision of those guidelines. Methods: In 2004, a nationwide questionnaire concerning current diagnostic routines was sent to all 45 paediatric clinics performing small bowel biopsy. All clinics responded. Results: All clinics base their diagnosis on small bowel biopsy findings at presentation. Furthermore, in 24 (53%) of the clinics, children with suspected coeliac disease are investigated by small bowel biopsy both at presentation and follow‐up while on a gluten‐free diet. Eighteen (40%) of the clinics employ a different diagnostic routine for children under 2 y of age than for those older than 2 y. All clinics use coeliac serological testing at various stages of the diagnostic procedure. Conclusion: All Swedish paediatric clinics perform a small bowel biopsy at presentation in children with suspected coeliac disease, and the majority of clinics perform a second biopsy when the child is on a gluten‐free diet. Serological testing is frequently used as a diagnostic aid and in the monitoring of the disease while on a gluten‐free diet.
A Mixture model with random-effects components for clustering correlated gene-expression profiles
Authors: Ng S. K. , McLachlan G. J. , Wang K. , Ben-Tovim Jones L. , Ng S.-W. 
Published: May 2006

AbstractMotivation: The clustering of gene profiles across some experimental conditions of interest contributes significantly to the elucidation of unknown gene function, the validation of gene discoveries and the interpretation of biological processes. However, this clustering problem is not straightforward as the profiles of the genes are not all independently distributed and the expression levels may have been obtained from an experimental design involving replicated arrays. Ignoring the dependence between the gene profiles and the structure of the replicated data can result in important sources of variability in the experiments being overlooked in the analysis, with the consequent possibility of misleading inferences being made. We propose a random-effects model that provides a unified approach to the clustering of genes with correlated expression levels measured in a wide variety of experimental situations. Our model is an extension of the normal mixture model to account for the correlations between the gene profiles and to enable covariate information to be incorporated into the clustering process. Hence the model is applicable to longitudinal studies with or without replication, for example, time-course experiments by using time as a covariate, and to cross-sectional experiments by using categorical covariates to represent the different experimental classes.Results: We show that our random-effects model can be fitted by maximum likelihood via the EM algorithm for which the E(expectation)and M(maximization) steps can be implemented in closed form. Hence our model can be fitted deterministically without the need for time-consuming Monte Carlo approximations. The effectiveness of our model-based procedure for the clustering of correlated gene profiles is demonstrated on three real datasets, representing typical microarray experimental designs, covering time-course, repeated-measurement and cross-sectional data. In these examples, relevant clusters of the genes are obtained, which are supported by existing gene-function annotation. A synthetic dataset is considered too.Availability: A Fortran program blue called EMMIX-WIRE (EM-based MIXture analysis WIth Random Effects) is available on request from the corresponding author.Contact: gjm@maths.uq.edu.auSupplementary information: . Colour versions of Figures 1 and 2 are available as Supplementary material on Bioinformatics online.
Hormonal regulation of mannan-binding lectin synthesis in hepatocytes
Authors: Sørensen C M , Hansen T K , Steffensen R , Jensenius J C , Thiel S 
Published: May 2006

SummaryActivation of the complement system via the plasma protein mannan-binding lectin (MBL) provides a first line of defence against infections. The plasma level of MBL is, in part, determined genetically, but may also be influenced by different hormones in vivo. Here we study the hormonal regulation of MBL synthesis from the human hepatocyte cell line HuH-7. Cells were exposed to medium with growth hormone (GH), hydrocortisone, insulin-like growth factor (IGF)-1, insulin, interleukin (IL)-6 or thyroid hormones (T3 or T4). After 3 days the concentration of MBL in the culture supernatants was determined and the amount of mRNA for MBL was measured, relative to mRNA for β2 microglobulin. GH, IL-6, T3 and T4 significantly increased MBL synthesis in a dose-dependent manner, while hydrocortisone, insulin and IGF-1 had no effect. T3 caused a fourfold increase at 1 nM of T3 (P &lt; 0·001) and at 100 nM of T3 the production was increased more than eightfold. The effect of T4 was less potent, reaching an eightfold increase at 1 µM of T4 (P &lt; 0·001). GH augmented the production of MBL threefold at a concentration of 100 ng/ml (P = 0·018) with no further effect up to 10 µg/ml, whereas IL-6 caused only a very weak increase in MBL production. MBL mRNA levels were stable during the first 24 h of T3 stimulation but increased significantly between 24 and 48 h. The results suggest that MBL synthesis in humans may be increased by thyroid hormone and GH, whereas it does not exhibit a classical IL-6-dependent response.
Plant nitrogen capture in pulse‐driven systems: interactions between root responses and soil processes
Authors: JAMES J. J. , RICHARDS J. H. 
Published: May 2006

Summary
Soil resources are heterogeneously distributed in natural systems. In arid systems, for example, soil nitrogen (N) is often supplied in pulses. Mechanisms influencing the ability of a species to exploit N pulses through the season, however, are poorly understood despite the strong potential for temporal variation in N supply to impact growth, survival and competitive interactions in these systems.
We examined how plant physiological and soil processes interacted to influence the ability of two dominant perennial Atriplex species to capture N from pulses occurring at different times in the growing season.
15N‐labelled pulses were applied to the two Atriplex species in early and mid spring. Sequential time harvests were used to quantify changes in plant 15N content, root length, root length relative growth rate, root N inflow rates, microbial biomass 15N, soil water content and soil inorganic 15N pools. Path analysis and structural equation modelling were used to quantify the relative importance of different root parameters for plant N capture from pulses and to evaluate the degree to which these root responses interacted with soil processes to influence plant N capture.
Plant N capture was greatest when pulses coincided with high root length relative growth rates. Declining availability of total inorganic N through a pulse had a limited effect on N capture. This was partly because soil pools were removed from the soil system four times faster than soil pools, allowing sufficient supply to roots, although total inorganic N pools declined. Microbial immobilization rates did not change significantly through a pulse and did not influence plant N capture during a pulse. Instead, plant N capture during a pulse was limited by total root length and uptake capacity per unit root length, which in turn was affected by plant N demand and soil water content.
Understanding interactions between root responses, soil processes and pulse timing provides insight into mechanisms underlying competitive interactions and diversity maintenance in pulse‐driven systems.