bluuebunny/crossref_metadata_2025 huggingface dataset:
Ensheathing cell cultures from the olfactory bulb and mucosa
Authors: Jani Harsha R. , Raisman Geoffrey
Published: April 2004

Transplantation of cells cultured from the nerve layers of the adult rat olfactory bulb has been shown to repair CNS tract injuries. The precise cellular composition of the culture appears to be important for this effect. Comparison was made of tissue cultured from the adult rat olfactory mucosa with that from the olfactory bulb. Both yielded mixtures of p75 immunoreactive cells and fibronectin immunoreactive cells. In sequential observations over 21 days in culture, the population of p75‐expressing cells was maintained and continued to proliferate for longer in the samples from the olfactory mucosa. For derivation of cells for transplantation, the mucosa can be accessed without the need for intracranial surgery. © 2004 Wiley‐Liss, Inc.
Laminin‐induced aggregation of the inwardly rectifying potassium channel, Kir4.1, and the water‐permeable channel, AQP4, via a dystroglycan‐containing complex in astrocytes
Authors: Guadagno Eric , Moukhles Hakima
Published: April 2004

Dystroglycan (DG) is part of a multiprotein complex that links the extracellular matrix to the actin cytoskeleton of muscle fibers and that is involved in aggregating acetylcholine receptors at the neuromuscular junction. This complex is also expressed in regions of the central nervous system where it is localized to both neuronal and glial cells. DG and the inwardly rectifying potassium channels, Kir4.1, are concentrated at the interface of astroglia and small blood vessels. These channels are involved in siphoning potassium released into the extracellular space after neuronal excitation. This raises the possibility that DG may be involved in targeting Kir4.1 channels to specific domains of astroglia. To address this question, we used mixed hippocampal cultures to investigate the distribution of DG, syntrophin, dystrobrevin, and Kir4.1 channels, as well as aquaporin‐permeable water channels, AQP4. These proteins exhibit a similar distribution pattern and form aggregates in astrocytes cultured on laminin. Both DG and syntrophin colocalize with Kir4.1 channel aggregates in astrocytes. Similarly, DG colocalizes with AQP4 channel aggregates. Quantitative studies show a significant increase of Kir4.1 and AQP4 channel aggregates in astrocytes cultured in the presence of laminin when compared with those in the absence of laminin. These findings show that laminin has a role in Kir4.1 and AQP4 channel aggregation and suggest that this may be mediated via a dystroglycan‐containing complex. This study reveals a novel functional role for DG in brain including K+ buffering and water homeostasis. © 2004 Wiley‐Liss, Inc.
Facile dissociation of BS coordination bonds in [2,6‐bis(ethylthiomethyl)phenyl]diethylborane by an SN2‐type mechanism
Authors: Toyota Shinji , Uemitsu Nobuhide , Ōki Michinori
Published: April 2004

The title organoboron complex undergoes dissociation of the intramolecular B–S coordination bond much faster than the corresponding mono ethylthiomethyl complex as revealed by the dynamic NMR study. The facile dissociation is attributable to an SN2‐type mechanism, where the uncoordinated ligand assists the dissociation of the coordinated ligand in the transition state. This mechanism is supported by the initio calculations of a model reaction system. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:241–245, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20005
Novel conversion of 6H‐1,3,5‐oxathiazine S‐oxides into 3H‐1,2,4‐dithiazoles by treating with Lawesson's reagent
Authors: Rafiqul Islam Md. , Shimada Kazuaki , Aoyagi Shigenobu , Fujisawa Yoriko , Takikawa Yuji
Published: April 2004

Treatment of 6H‐1,3,5‐oxathiazine S‐oxides by Lawesson's reagent (LR) at high temperature furnished 3H‐1,2,4‐dithiazoles in moderate to good yields. Deoxygenation of 6H‐1,3,5‐oxathiazine S‐oxides was performed by LR in the presence of EtOH. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:208–215, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20011
Synthesis of new potential chelating agents: Catechol–bisphosphonate conjugates for metal intoxication therapy
Authors: Xu Guangyu , Yang Chunhao , Liu Bo , Wu Xihan , Xie Yuyuan
Published: April 2004

In a quest for better chelating therapy drugs for the treatment of intoxication by Fe, Al, or actinides, three new series of bisphosphonates conjugated with catechol were synthesized. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:251–257, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20013
Developmental expression of glutamate transporters and glutamate dehydrogenase in astrocytes of the postnatal rat hippocampus
Authors: Kugler Peter , Schleyer Verena
Published: April 2004

Glutamate is the major excitatory transmitter in the CNS and plays distinct roles in a number of developmental events. Its extracellular concentration, which mediates these activities, is regulated by glutamate transporters in glial cells and neurons. In the present study, we have used nonradioactive in situ hybridization, immunocytochemistry, and immunoblotting to show the cellular and regional expression of the high‐affinity glutamate transporters GLAST (EAAT1) and generic GLT1 (EAAT2; glial form of GLT1) in the rat hippocampus during postnatal development (P1–60). The results of transporter expression were compared with the localization and activity pattern of glutamate dehydrogenase (GDH), an important glutamate‐metabolizing enzyme. The study showed that both transporters and GDH were demonstrable at P1 (day of birth). The expression of GLAST (detected by in situ hybridization and immunocytochemistry) in the early postnatal development was higher than GLT1. Thereafter, the expression of both transporters increased, showing adult levels at between P20 and P30 (detected by in situ hybridization and immunoblotting). At these time points, the expression of GLT1 appeared to be significantly higher than the GLAST expression. GLT1 and GLAST proteins were demonstrable only in astrocytes. The increase of GDH activities (steepest increase from P5–P8), which were localized preferentially in astrocytes, was in agreement with the increase of transporter expression, preferentially with that of GLT1. These observations suggest that the extent of glutamate transporter expression and of glutamate‐metabolizing GDH activity in astrocytes is intimately correlated with the formation of glutamatergic synapses in the developing hippocampus. © 2004 Wiley‐Liss, Inc.
Genetic abnormalities in plasma DNA of patients with lung cancer and other respiratory diseases
Authors: Khan Sarah , Coulson Judy M. , Woll Penella J.
Published: April 2004

The detection of tumour‐associated genetic alterations in plasma DNA has been proposed as a simple method for the early diagnosis of lung cancer and for identifying individuals at high risk of lung cancer who might be included in screening or chemoprevention programmes. To evaluate the practicality of this approach, we screened a panel of 16 plasma DNA markers in a lung cancer population to identify those with the highest genetic alteration rate. These were then used to study plasma DNA in 206 hospital outpatients with lung cancer and other respiratory diseases. Plasma and lymphocyte DNA were isolated from blood samples collected from hospital outpatients. Polymerase chain reaction was carried out with 16 microsatellite markers covering chromosomal regions 3p, 8p, 9p, 13q and 17p, using DNA from 32 lung cancer patients. The 3 markers most commonly affected were selected for use in a larger study of 86 lung cancer patients and 120 patients with other respiratory diseases. In the pilot study, 3 primer pairs (D3S1300, D3S1560, D8S201) together detected genetic alterations in plasma DNA in 60% of lung cancer patients. In the larger study, significantly higher genetic alteration rates were observed in lung cancer patients than in patients with other respiratory diseases for the two markers D3S1560 and D8S201. The overall genetic alteration rate was 69% in the lung cancer patients and 42% in the patients with other respiratory diseases (p < 0.001). Analysis of plasma and lymphocyte DNA to detect genetic alterations typical of lung cancer is possible in large studies. The genetic alteration rate we found in lung cancer patients was comparable with other studies. Although the genetic alteration rate was significantly higher in the lung cancer than the respiratory disease patients, it did not have good positive predictive value in this population. Longitudinal studies are required to determine whether genetic changes in plasma DNA of non‐cancer patients indicate a high risk of later lung cancer. © 2004 Wiley‐Liss, Inc.
The variant E233G of the RAD51D gene could be a low‐penetrance allele in high‐risk breast cancer families without BRCA1/2 mutations
Authors: Rodríguez‐López Raquel , Osorio Ana , Ribas Gloria , Pollán Marina , Sánchez‐Pulido Luis , de la Hoya Miguel , Ruibal Álvaro , Zamora Pilar , Arias Jose Ignacio , Salazar Raquel , Vega Ana , Martínez Jose Ignacio , Esteban‐Cardeñosa Eva , Alonso Carmen , Letón Rocío , Urioste Azcorra Miguel , Miner Cristina , Armengod M. Eugenia , Carracedo Angel , González‐Sarmiento Rogelio , Caldés Trinidad , Díez Orland , Benítez Javier
Published: April 2004

Six SNPs have been detected in the DNA repair genes RAD51C and RAD51D, not previously characterized. The novel variant E233G in RAD51D is more highly represented in high‐risk, site‐specific, familial breast cancer cases that are not associated with the BRCA1/2 genes, with a frequency of 5.74% (n = 174) compared to a control population (n = 567) and another subset of breast cancer patients (n = 765) with a prevalence of around 2% only (comparison to controls, OR = 2.6, 95% CI 1.12–6.03; p < 0.021). We found that the immunohistochemical profile detected in available tumors from these patients differs slightly from those described in non‐BRCA1/2 tumors. Finally, the structural prediction of the putative functional consequence of this change indicates that it can diminish protein stability and structure. This suggests a role for E233G as a low‐penetrance susceptibility gene in the specific subgroup of high‐risk familial breast cancer cases that are not related to BRCA1/2. © 2004 Wiley‐Liss, Inc.
Evaluation of circulating thyroid‐specific transcripts as markers of thyroid cancer relapse
Authors: Barzon Luisa , Boscaro Marco , Pacenti Monia , Taccaliti Augusto , Palù Giorgio
Published: April 2004

Circulating thyroid‐specific transcripts have been suggested as potential molecular markers of residual or recurrent thyroid cancer. We assessed the accuracy of real‐time RT‐PCR‐based detection of a panel of thyroid‐specific markers, including TG, TPO, TSHR, NIS and PDS, in comparison with serum TG measurements in a series of 55 patients operated for differentiated thyroid cancer (DTC). Serum TG levels were higher in patients with residual thyroid tissue or metastatic cancer than in disease‐free patients during thyroid hormone suppressive therapy (THST) and after stimulation with rhTSH (P < 0.05). Recombinant hTSH increased serum TG values in patients with tumor relapse (P < 0.05), but not in disease‐free patients. This assay showed high specificity and good sensitivity in detecting tumor relapse (accuracy under THST = 81.4%; after rhTSH stimulation = 90.9%). TPO and TSHR mRNA, either under THST or after rhTSH, showed a significant correlation with disease status for molecular assays. Qualitative analysis of baseline and stimulated TG, NIS and PDS mRNA showed high sensitivity but low specificity in the prediction of thyroid cancer recurrence or metastases (accuracy under THST = 51%, 43% and 54%, respectively), whereas TPO and TSHR mRNA assays had higher specificity but low sensitivity, with accuracy under THST of 67% and 61%, respectively, that improved when these tests were combined. Our findings indicate that serum TG assay after TSH stimulation is the most accurate test for monitoring DTC. Combined measurements of TPO and TSHR mRNA levels during THST may represent a specific test for early detection of DTC relapse. © 2004 Wiley‐Liss, Inc.
Degradation and cell culture studies on block copolymers prepared by ring opening polymerization of ϵ‐caprolactone in the presence of poly(ethylene glycol)
Authors: Huang Ming‐Hsi , Li Suming , Hutmacher Dietmar Werner , Schantz Jan‐Thorsten , Vacanti Charles Alfred , Braud Christian , Vert Michel
Published: April 2004

Poly(ϵ‐caprolactone) (PCL) and its block copolymers with poly(ethylene glycol) (PEG) were prepared by ring‐opening polymerization of ϵ‐caprolactone in the presence of ethylene glycol or PEG, using zinc metal as catalyst. The resulting polymers were characterized by various analytical techniques such as 1H NMR, SEC, DSC, IR, X‐ray, ESEM, and CZE. PCL/PEG copolymers with long PCL chains presented the same crystalline structure as PCL homopolymer, whereas PEG‐bearing short PCL blocks retained the crystalline structure of PEG and exhibited an amphiphilic behavior in aqueous solutions. Degradation of PCL and PCL/PEG diblock and triblock copolymers was realized in a 0.13 M, pH 7.4 phosphate buffer at 37°C. The results indicated that the copolymers exhibited higher hydrophilicity and degradability compared with the PCL homopolymer. Large amounts of PEG were released from the bulk after 60 weeks' degradation. In vitro cell culture studies were conducted on scaffolds manufactured via solid free form fabrication by using primary human and rat bone marrow derived stromal cells (hMSC, rMSC). Light, scanning electron, and confocal laser microscopy, as well as immunocytochemistry, showed cell attachment, proliferation, and extracellular matrix production on the surface, as well as inside the scaffold architecture. Copolymers showed better performance in the cell culture studies than the PCL homopolymer. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 417–427, 2004
Modulation of differentiation and mineralization of marrow stromal cells cultured on biomimetic hydrogels modified with Arg‐Gly‐Asp containing peptides
Authors: Shin Heungsoo , Zygourakis Kyriacos , Farach‐Carson Mary C. , Yaszemski Michael J. , Mikos Antonios G.
Published: April 2004

We synthesized biomimetic hydrogels modified with an osteopontin‐derived peptide (ODP) and used them as a substrate for in vitro culture of marrow stromal cells (MSCs) to investigate the effect of the biomimetic surface on differentiation of MSCs into osteoblasts. Proliferation and biological assays for 16 days proved that MSCs became differentiated into osteoblasts secreting osteogenic phenotypic markers such as alkaline phosphatase (ALP), osteopontin, and mineralized calcium. In addition, there was an additive effect of the cell‐binding peptide on differentiation and mineralization of MSCs cultured in the presence of soluble osteogenic supplements in cell culture media. For example, calcium content at day 16 on peptide‐modified hydrogels was significantly higher than on tissue culture polystyrene. Two general trends were observed: (1) proliferation of MSCs decreased as the amount of differentiation markers increased, and (2) higher peptide concentrations accelerated the differentiation of MSCs. On the hydrogel modified with ODP, ALP activity exhibited a maximum value of 36.7 ± 4.2 pmol/cell/h at day 10 for the concentration of 2 μmol/g while the culture time needed for maximum ALP activity occurred on day 13 for the lower concentrations. On the same hydrogel, the calcium content at day 10 was 21.4 ± 2.3 ng/cell for the peptide concentration of 2 μmol/g and 1.0 ± 0.3 ng/cell for 1.0 μmol/g. We used Gly‐Arg‐Gly‐Asp‐Ser (GRGDS) for modification of the hydrogel as a comparison to the results with ODP. However, osteoblast development was not significantly affected by the nature of the binding peptide sequences. These results suggest that MSC function can be modulated by variation of the peptide concentration in biomimetic hydrogels used for scaffold‐based bone tissue engineering. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 535–543, 2004
Gentamicin release from two‐solution and powder–liquid poly(methyl methacrylate)‐based bone cements by using novel pH method
Authors: Merkhan Imad K. , Hasenwinkel Julie M. , Gilbert Jeremy L.
Published: April 2004

The release of gentamicin as a function of time was measured for Palacos and two‐solution bone cements by using a novel pH technique. The pH of an aqueous solution of gentamicin is a function of the gentamicin concentration and it decreases linearly over concentrations of 0.0–0.1 wt %. Therefore, a new, direct, and inexpensive in vitro technique was developed based on continuous readings of the pH in phosphate‐buffered saline (PBS) at 37°C to determine the release kinetics of gentamicin from poly(methyl methacrylate) (PMMA)‐based bone cement. In addition, this method was used to compare the release profiles of Palacos R‐40 bone cement with a two‐solution bone cement developed in our laboratory and loaded with two different concentrations of gentamicin sulfate. Finally, the pH‐based method was used to track the elution of gentamicin in both mixed and static conditions to determine the effect of mixing on the diffusion of gentamicin out of the cement. It was found that Palacos R‐40 released 4.95 ± 0.22 wt % of its gentamicin after 24 h in PBS solution. This data compares favorably with previously reported values of gentamicin elution from Palacos R‐40, which ranged from 3 to 8 wt % of the total amount of incorporated gentamicin, depending on the size and the surface area of the samples. The results show that Palacos samples released 4.84 ± 0.27 mg after 24 h, a two‐solution cement loaded with an equivalent concentration of gentamicin sulfate released 3.81 ± 0.52 mg, and two‐solution cement loaded with twice the concentration of Palacos released 5.53 ± 0.26 mg of gentamicin. A higher percentage of release was recorded from Palacos than from the two‐solution bone cement, and the effect of PBS mixing conditions on the release kinetics was only significant in the early stages of release and not at 24 h. It was concluded that monitoring the pH is an effective technique to measure gentamicin release from PMMA‐based bone cements in PBS solution. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 577–583, 2004
Micromechanical analysis of dentin/adhesive interface by the finite element method
Authors: Misra Anil , Spencer Paulette , Marangos Orestes , Wang Yong , Katz J. Lawrence
Published: April 2004

The interfacial microstructure and spatial distribution of the modulus of elasticity have a profound effect on load transfer at the dentin/adhesive (d/a) interface. The microstructure is influenced by the varying degree of demineralization of intertubular and peritubular dentin during etching as well as the depth of adhesive penetration into the hybrid layer. These factors lead not only to a unique microstructure in the vicinity of the dentinal tubules, but also to a mechanically graded hybrid layer. This article investigates the micromechanical stress distribution at a d/a interface with the use of finite element analysis (FEA). Such analysis is now feasible given the newly measured moduli of elasticity at micro‐ and nanoscales. The results indicate that the morphological and micromechanical properties of the d/a interface affects the stress field such that the fracture/failure is likely to initiate in the stress‐concentration zone of peritubular dentin next to the hybrid/exposed‐collagen layer. The results suggest that devising a full‐depth high modulus hybrid layer may considerably reduce the stress concentration zone and the magnitude of stress concentration in the peritubular dentin next to the hybrid/exposed‐collagen layer. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 56–65, 2004
Effects of water storage of E‐glass fiber reinforced denture base polymers on residual methyl methacrylate content
Authors: Bayraktar Gulsen , Duran Ozlem , Bural Canan , Guvener Bora
Published: April 2004

This study investigated the effect of water storage on residual methyl methacrylate (MMA) content of continuous E‐glass fiber (Wetrotex International) reinforced denture base polymers. Heat‐polymerization (short‐ and long‐term boiling and conventional curing cycle using Meliodent™), autopolymerization (processed in air at room temperature and in water at 60°C with the use of Meliodent Rapid Repair™), and microwave‐polymerization (3 min at 500 W with the use of Acron MC™) were employed. The residual MMA contents of 120 specimens were analyzed by high‐performance liquid chromatography at deflasking (control) and after water (37°C) storage of 1 day, 1 week, and 1 month. Bonferroni's pairwise comparison test was used for statistical analysis. Significant reduction were determined only in the long‐term terminal boiled heat‐polymerized test group at the end of 1 day (p < 0.01), 1 week (p < 0.05) and also 1 month of water storage (p < 0.01). Significant reduction in autopolymerized test groups started even after 1 week of water storage (p < 0.05). Microwave‐polymerized test groups did not show a significant residual MMA reduction in all time intervals (p > 0.05). The polymerization methods and cycles applied to the glass fiber reinforced denture base polymers influence both the content and the reduction of residual MMA after water storage. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 161–166, 2004
A precise boundary element method for macromolecular transport properties
Authors: Aragon Sergio
Published: April 2004

A very precise boundary element numerical solution of the exact formulation of the hydrodynamic resistance problem with stick boundary conditions is presented. BEST, the Fortran 77 program developed for this purpose, computes the full transport tensors in the center of resistance or the center of diffusion for an arbitrarily shaped rigid body, including rotation‐translation coupling. The input for this program is a triangulation of the solvent‐defined surface of the molecule of interest, given by Connolly's MSROLL or other suitable triangulator. The triangulation is prepared for BEST by COALESCE, a program that allows user control over the quality and number of triangles to describe the surface. High numerical precision is assured by effectively exact integration of the Oseen tensor over triangular surface elements, and by scaling the hydrodynamic computation to the precise surface area of the molecule. Efficiency of computation is achieved by the use of public domain LAPACK routines that call BLAS Level 3 hardware‐optimized subroutines available for most processors. A protein computation can be done in less than 10 min of CPU time in a modern Pentium IV processor. The present work includes a complete analysis of the sources of error in the numerical work and techniques to eliminate these errors. The operation of BEST is illustrated with applications to ellipsoids of revolution, and Lysozyme, a small protein. The typical numerical accuracy achieved is 0.05% compared to analytical theory. The numerical precision for a protein is better than 1%, much better than experimental errors in these quantities, and more than 10 times better than traditional bead‐based methods. © 2004 Wiley Periodicals, Inc. J Comput Chem 9: 1191–1205, 2004
GAD67 and GAD65 mRNA and protein expression in cerebrocortical regions of elderly patients with schizophrenia
Authors: Dracheva Stella , Elhakem Sharif L. , McGurk Susan R. , Davis Kenneth L. , Haroutunian Vahram
Published: April 2004

γ‐Aminobutyric acid (GABA), the principal inhibitory neurotransmitter of CNS, has been consistently implicated in the pathophysiology of schizophrenia. GABA is synthesized from glutamate by the enzyme glutamic acid decarboxylase (GAD). Two isoforms of GAD have been identified and have been named GAD65 and GAD67 based on their apparent molecular weights. In this study, GAD65 and GAD67 mRNA and protein levels were measured by using real‐time RT‐PCR and immunoblotting, respectively, in post‐mortem brain tissue from the dorsolateral prefrontal cortex (DLPFC) and the occipital cortex of the elderly persons with schizophrenia and matched normal controls. In addition, the mRNA expression of GAT‐1, one of the principal transporters of GABA, was also studied in the same subjects. Expression of GAD65 and GAD67 mRNA in the DLPFC and in the occipital cortex was significantly elevated in patients with schizophrenia, whereas the expression of the corresponding proteins and GAT‐1 mRNA was unchanged. Although the levels of GAD65 and GAD67 messages were increased in schizophrenia subjects, the proportion of the two GAD isoforms remained constant in controls and schizophrenics. In the human DLPFC, GAD65 mRNA was found to be expressed significantly less than the message for GAD67, approximately 16% of that observed for GAD67. On the contrary, the abundance of GAD65 protein in the DLPFC was about 350% of that observed for GAD67. The results suggest a substantial dysregulation of GAD mRNA expression in schizophrenia and, taken together with the results of protein expression studies, raise the possibility that both cortical and subcortical GABA function may be compromised in the disease. © 2004 Wiley‐Liss, Inc.
Inhibition of methyl linoleate autoxidation by phenolics and other related compounds under mild oxidative conditions
Authors: Dávalos Alberto , Bartolomé Begoña , Gómez‐Cordovés Carmen
Published: April 2004

Methyl linoleate (MeLo) is a commercially available substrate widely used for studying the inhibitory properties of pure compounds and plant extracts against lipid oxidation. In this paper, 13 phenolic (benzoic and cinnamic acids, aldehydes and derivatives, and flavonoids) and other related compounds (butylated hydroxyanisole, butylated hydroxytoluene and tocopherols) as well as nine complex mixtures rich in phenolics (wines) or tocopherols (soybean oil extracts) were assayed for their inhibitory activity against MeLo autoxidation under mild conditions (40 °C, darkness and atmospheric pressure). Samples were also assayed for their free radical‐scavenging capacity against 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH•). Protocatechuic aldehyde, a compound that has not been previously evaluated by either of the two methods, showed the highest antioxidant activity. Some variations in the antioxidant ranking for some compounds were found between our results and those obtained by other authors using accelerated conditions for MeLo oxidation. Antioxidant activity of wines and soybean oil extracts was related to their richness in phenolics and tocopherols respectively. Correlation between antioxidant capacity measured by the MeLo and DPPH• methods was found for wines but not for the other samples studied. Therefore the measure of the free radical‐scavenging capacity of a compound is not always a reliable indicator of its lipid oxidation inhibitory ability. Copyright © 2004 Society of Chemical Industry
Pre‐harvest calcium treatments in relation to the respiration rate and ethylene production of ‘Golden Smoothee’ apples
Authors: Recasens I , Benavides A , Puy J , Casero T
Published: April 2004

Multivariate procedures were used to evaluate the effect of different pre‐harvest calcium treatments on the changes of respiratory rate and ethylene production in apples both at harvest and after extended cold storage. The study was carried out over two years on ‘Golden Smoothee’ apple trees from Lleida (Spain). Trees were sprayed with a calcium chloride based formulation (STOPIT) at a concentration of 1% (v/v). The first (6 applications) and second (12 applications) treatments began 60 days after full bloom (DAFB) and were repeated at intervals of 15 and 7 days respectively. After harvesting, the fruit was stored for 4 and 6 months under controlled ultra‐low oxygen atmosphere conditions (CA‐ULO). Each time fruit was withdrawn from storage, carbon dioxide and ethylene production were measured for 14 days at 20 °C. Independently of the calcium treatments, respiration rates fell from harvesting until 6 months of storage, while ethylene production was greater on withdrawal from storage than at harvest. Respiratory rate and ethylene production correlated negatively with calcium content. However, calcium apparently had a greater effect on the respiratory capacity (CO2) of fruit than on ethylene production. Copyright © 2004 Society of Chemical Industry
Fluoride: A toxic or therapeutic agent in the treatment of osteoporosis?
Authors: Aaseth Jan , Shimshi Mona , Gabrilove J. Lester , Birketvedt Grethe Støa
Published: April 2004

This article summarizes recent studies and is a review of the literature on the fluoride compounds and their influence on bone mineral mass. It is well known that fluoride is an important element for mineralization of body tissues. The use of topical and systemic fluoride for oral health has resulted in major reduction in dental caries, but fluoride also plays a role in bone health. Dieticians and other health professionals are advised to recommend adequate use of systemic and topical fluorides, especially in children and adolescents. Population studies as well as earlier studies of individuals exposed to fluorides indicate that doses above 30–40 mg daily can result in fluorosis, characterized by increased fracture risk. Numerous clinical studies have demonstrated increased bone mineral density in subjects treated with appropriate doses of fluoride. However, the clinical interpretation of these studies has been a matter of debate. Therapeutically, fluoride seems to be useful when the agent is started in the early stages of osteoporosis, especially in patients with intact trabecular bone. It is well established that fluoride can act as an effective stimulator of bone formation by the osteoblasts. Bisphosphonates, which can also increase bone density, act by inhibiting bone resorption by osteoclasts. As a result of this, owing to the tight paracrine association characterizing skeletal metabolism, bone formation is slowed down by the antiresorptive agents. It is of particular interest that great benefit in the treatment of osteoporoses is seen when adequate osteoblast‐stimulating doses of fluorides are given in combination with antiresorptive medication, but further research is needed to substantiate this promising concept. J. Trace Elem. Exp. Med. 17:83–92, 2004. © 2004 Wiley‐Liss, Inc.
Effect of aging on sensory nerve conduction study parameters
Authors: Tong Henry C. , Werner Robert A. , Franzblau Alfred
Published: April 2004

Research evaluating the changes in nerve conduction with time has been limited to cross‐sectional studies. We present a cohort study estimating how sensory nerve conduction study (NCS) parameters change with time when subjects are measured at two time‐points. We evaluated 440 working adults by performing median and ulnar antidromic sensory NCS of both hands on two occasions, about 5.4 years (range, 4.3–7.0 years) apart. The rate of change in the NCS parameters was estimated using a mixed‐models analysis controlling for each hand, gender, age, and body mass index (BMI). After controlling for gender, age, height, and BMI, the amplitudes of the median sensory nerve action potentials (SNAP) decreased by about 2.3 μV, peak latencies increased by 0.11 ms, onset latencies increased by 0.07 ms, and conduction velocities decreased by 1.1 m/s over 5 years. Corresponding values for the ulnar nerve were 1.75 μV, 0.06 ms, 0.04 ms, and 0.71 m/s, respectively. The findings are consistent with the findings of previous cross‐sectional studies. The rate of change over time was not affected by hand (dominant versus nondominant hand), gender, age, or BMI at baseline. The rate of change seen with some of the median nerve parameters was significantly greater than that with the ulnar nerve. Muscle Nerve 29: 716–720, 2004
Posterior tibial nerve stimulation in the treatment of voiding dysfunction: Urodynamic data
Authors: Vandoninck Vera , van Balken Michael R. , Finazzi Agrò Enrico , Heesakkers John P.F.A. , Debruyne Frans M.J. , Kiemeney Lambertus A.L.M. , Bemelmans Bart L.H.
Published: April 2004

Objectives

To determine urodynamic changes and predictive factors in patients with voiding dysfunction who underwent 12 percutaneous tibial nerve stimulations.

Methods

Thirty nine patients with chronic voiding dysfunction were enrolled in a prospective multicenter trial in the Netherlands (n = 19) and in Italy (n = 20). A 50% reduction in total catheterised volume per 24 hr was taken as a primary objective outcome measure. Patients' request for continuation of treatment was regarded as subjective success. Objective urodynamic parameters and bladder indices were determined. Odds ratios and their 95% confidence interval were computed as a measure for predictive power in order to reveal predictive factors (Pdet at Qmax, Qmax, BVE, and BCI).

Results

Primary outcome measure was obtained in 41%, an additional 26% reduced their 24 hr residuals with more than 25%. Fifty nine percent of patients chose to continue treatment. Detrusor pressure at maximal flow, cystometric residuals, and bladder indices improved significantly for all patients (P < 0.05). Patients with minor voiding dysfunction were more prone to notice success (Odds ratio: 0.73; 95% CI: 0.51–0.94).

Conclusions

PTNS is a young treatment modality, minimally invasive, and easily accessible. It might be an attractive first line option for patients with (minor) voiding dysfunction. Neurourol. Urodynam. 23:246–251, 2004. © 2004 Wiley‐Liss, Inc.
ERRATUM: Rapid electrical and delayed molecular signals regulate the serum response element after nerve injury: Convergence of injury and learning signals
Authors: Lin Hana , Bao Jianxin , Ying Ju‐Sung , Walters Edgar T. , Ambron Richard T.
Published: April 2004

The original article to which this Erratum refers was published inJournal of Neurobiology (2003) 57(2) 204–220

The name of the third author of this article was spelled incorrectly. It should read:

Ying‐Ju Sung

The publisher regrets this error.
Natural superconvergent points of triangular finite elements
Authors: Lin Runchang , Zhang Zhimin
Published: April 2004

In this work, we analytically identify natural superconvergent points of function values and gradients for triangular elements. Both the Poisson equation and the Laplace equation are discussed for polynomial finite element spaces (with degrees up to 8) under four different mesh patterns. Our results verify computer findings of Babuška et al., especially, we confirm that the computed data have 9 digits of accuracy with an exception of one pair (which has 8‐7 digits of accuracy). In addition, we demonstrate that the function value superconvergent points predicted by the symmetry theory of Schatz et al. are the only superconvergent points for the Poisson equation. Finally, we provide function value superconvergent points for the Laplace equation, which are not reported elsewhere in the literature. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2004.
A new linearized method for Benjamin‐Bona‐Mahony equations
Authors: Li Chen , Wu Xionghua
Published: April 2004

In this article, a new method called linearized and rational approximation method based on differential quadrature method (DQM) is proposed for the Benjamin‐Bona‐Mahony (BBM) equation on a semi‐infinite interval. Numerical result indicates the high accuracy and relatively little computational effort of this method. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2004
Resin transfer molding process optimization using numerical simulation and design of experiments approach
Authors: Gou Jihua , Zhang Chuck , Liang Zhiyong , Wang Ben , Simpson James
Published: April 2004

The art of resin transfer molding (RTM) process optimization requires a clear understanding of how the process performance is affected by variations in some important process parameters. In this paper, maximum pressure and mold filling time of the RTM process are considered as characteristics of the process performance to evaluate the process design. The five process parameters taken into consideration are flow rate, fiber volume fraction, number of gates, gate location, and number of vents. An integrated methodology was proposed to investigate the effects of process prameters on maximum pressure and mold filling time and to find the optimum processing conditions. The method combines numerical simulation and design of experiments (DOE) approach and is applied to process design for a cylindrical composite part. Using RTM simulation, a series of numerical experiments were conducted to predict maximum pressure and mold filling time of the RTM process. A half‐fractional factorial design was conducted to identify the significant factors in the RTM process. Furthermore, the empirical models and sensitivity coefficients for maximum pressure and mold filling time were developed. Comparatively close agreements were found among the empirical approximations, numerical simulations, and actual experiments. These results were further utilized to find the optimal processing conditions for the example part.
Ionic polymer‐metal composites as multifunctional materials
Authors: Shahinpoor Mohsen , Kim Kwang J. , Leo Don J.
Published: April 2004

This paper presents a description and a set of experimental results on Ionic Polymer‐Metal Composites (IPMC's) as dynamic sensors, transducers, and actuators. Strips of IPMC can exhibit large dynamic deformation if placed in a time‐varying electric field of the order of 10's of volts/mm. Conversely, dynamic deformation and flexing of such ionic polymers produces dynamic electric fields that closely follow the form of the electric signal. The underlying principle of such a mechanoelectric effect in IPMC's can be explained by the linear irreversible thermodynamics in which ion and solvent transport are the fluxes and electric field and solvent pressure gradient are the forces. Important parameters include the material conductance and the solvent permeability. The dynamic sensing, transduction, and actuation responses of a strip of IPMC under an impact‐type loading is also discussed. When a cantilever strip of IPMC is flipped, a damped oscillatory electric response is produced across a pair of electrodes placed at the cantilever of the strip, which is highly repeatable with a broad frequency range above 104 Hz. Such direct mechanoelectric responses of IMPC's are related to the endo‐ionic mobility due to stresses imposed. Imposition of a finite solvent flux without allowing a current flux causes the material to create a certain conjugate electric field that can be dynamically monitored and measured. IPMC's are shown to be highly capacitive at low frequencies while they are highly resistive under high frequency excitations. IN a sending mode, IPMC strips can also sense chemical environments and humidity. These types of sensors/transducers/actuators conceivably can replace piezoresistive and piezoelectric sensors with just one sensor for broad ranges of frequencies.
Cure temperature effects on cryogenic microcracking of polymeric composite materials
Authors: Timmerman John F. , Hayes Brian S. , Seferis James C.
Published: April 2004

A model prepreg system was used to evaluate the effect of cure temperature on microcracking in polymeric composite materials exposed to cryogenic cycling. Symmetic and unsymmetric carbon fiber/epoxy laminates were fabricated to examine the development of thermal stresses and microcracks at cryogenic temperatures. The residual strains and theoretical curvatures of the laminates were calculated from the composite properties and correlated with the microcrack density and experimentally observed curvatures. Higher cure temperatures resulted in higher stress free temperatures and residual strains in the laminates, which corresponded directly to increased levels of microcracking.
Investigation of convective heating in a polymer fiber drawing process
Authors: Reeve Hayden M. , Mescher Ann M. , Emery Ashley F.
Published: April 2004

Polymer optical fibers are drawn from a preform rod in a manufacturing process that requires heating. A polymer preform in a tubular furnace enclosure receives energy from the furnace wall via natural convection and thermal radiation. Natural convection, in comparison to radiation, contributes a smaller fraction of the total energy required during the transient heating of the preform and also during the fiber drawing. Based on numerical predictions, natural convection and radiation contribute approximately equal heating to the preform when it is initially introduced at room temperature into a preheated furnace. As the preform temperature rises, the fraction of convective heating decreases as a result of weakening of gas‐phase circulation cell(s) between the furnace wall and preform. These findings are supported by the measured temperature histories in the interior of the preforms that, for all of the cases studied, differed by less than 1.3°C from numerical predictions. Although radiation contributes a larger fraction of the total required energy, natural convection can nevertheless have a strong and detrimental effect on the fiber quality. Specifically, convective instabilities caused air temperature oscillations of 0.3 to 2°C with frequencies from 0.01 to 0.30 Hz. Experimental observations show that these gas phase temperature oscillations promote unwanted diameter variations during fiber drawing.
Wetting of a fiber bundle in fibrous structures
Authors: Lukas David , Pan Ning
Published: April 2004

In this paper we dealt with the problem of wetting and ascending of a liquid along a fiber bundle. Two issues are first addressed including the criterion for complete wetting of the fiber bundle and the ascension liquid profile on a partially dipped vertical fiber bundle. Both topics are studied theoretically by deriving a mathematical theory by which predictions are generated and important parametric analyses are carried out. Further, a 3D Ising model is used for computer modeling to simulate the fiber wetting and liquid ascending processes on a partially dipped single fiber. The significance and potential applications of the study are also summarized.
All‐plant fiber composites. II: Water absorption behavior and biodegradability of unidirectional sisal fiber reinforced benzylated wood
Authors: Lu Xun , Zhang Ming Qiu , Rong Min Zhi , Shi Guang , Yang Gui Cheng
Published: April 2004

Sisal fiber reinforced benzylated fir sawdust composites belong to a new category of composite materials, in which both the reinforcement and matrix are based on plant fibers, i.e. renewable resources. The present paper discusses the water absorption behavior of the composites and its influence on the mechanical properties of the composites. In addition, biodegradability of the composites is assessed by using enzyme and fungi tests, respectively. The experimental results indicate that water absorption behavior of the composites is mainly controlled by the reinforcing fiber and the fiber/matrix interfacial characteristics. The inherent biodegradability of the raw materials of the all‐plant fiber composites proves to be retained. During the tests of enzymolysis and biodeterioration in soil, damage of the composites was initiated either inside the sisal fiber or at the surface of the composites.
Application of digital speckle photography to measure thickness variations in the vacuum infusion process
Authors: Andersson H. M. , Lundström T. S. , Gebart B. R. , Synnergren P.
Published: April 2004

A new method to measure the movement of the flexible bag used in vacuum infusion is presented. The method is based on an in‐house developed stereoscopic digital speckle photography system (DSP). The advantage with this optical method, which is based on cross‐correlation, is that the deflection of a large area can be continuously measured with a great accuracy (down to 10 μm). The method is at this stage most suited for research but can in the long run also be adopted in production control and optimization. By use of the method it was confirmed that a ditch is formed at the resin flow front and that there can be a considerable and seemingly perpetual compaction after complete filling. The existence of the ditch demonstrates that the stiffness of the reinforcement can be considerably reduced when it is wetted. Hence, the maximum fiber volume fraction can be larger than predicted from dry measurements of preform elasticity. It is likely that the overall thickness reduction after complete filling emanates from lubrication of the fibers combined with an outflow of the resin. Besides, the cross‐linking starts and the polymer shrinks. Hence, the alteration in height will continue until complete cross‐linking is reached.
Effect of high‐energy vibro‐milling of filler on the mechanical properties of filled high‐density polyethylene
Authors: Guo Shaoyun , Wu Hong , Chen Guangshun , Chen Xiangrong
Published: April 2004

The effect of high‐energy mechanical milling of CaCO3 (calcium carbonate) and STC (a mixture of sericite, tridymite and cristobalite) on mechanical properties, rheological and dynamical mechanical behavior of high‐density polyethylene (HDPE)/CaCO3 and HDPE/STC was studied through SEM (scanning electron microscope), DMTA (dynastic mechanical test analysis), mechanical and melt rheological properties tests. The experimental results show that addition of fillers treated by coupling agent and vibromilling to HDPE makes the impact strength of HDPE greatly increased. The impact strength of HDPE/treated CaCO3 (60/40) and HDPE/treated STC (60/40) is ca. 4 and 3 times respectively as high as that of HDPE. The SEM micrographs of impact fractured surfaces of treated fillers filled HDPE show extensive plastic deformation of HDPE matrix, indicating that the plastic deformation of matrix induced by the treated fillers is the main contribution for absorbing a great amount of impact energy. This is the reason why the impact strength of HDPE greatly increases with addition of coupling agent and vibromilling treated fillers. The intensity of γ relaxation peak of HDPE in HDPE/treated CaCO3 on tanδ vs. temperature curve increases and the peak shifts to higher temperature due to its stronger interface interaction as compared with that of HDPE/untreated CaCO3.
Low‐velocity impacts in continuous glass fiber/polypropylene composites
Authors: Trudel‐Boucher David , Bureau Martin N. , Denault Johanne , Fisa Bo
Published: April 2004

The low‐velocity impact behavior of a continuous glass fiber/polypropylene composite was investigated. Optical microscopy and ultrasonic scanning were used to determine the impact‐induced damage. At low impact energy, the predominant damage mechanism observed was matrix cracking, while at high energy the damage mechanisms observed were delamination, plastic deformation, which produced a residual specimen curvature, and a small amount of fiber breakage at the edge of the indentation on the impacted face of the specimens. The impact load vs. time signals were recorded during impact and showed that the load corresponding to the onset of delamination was independent of the impact energy in the range tested. The load at which the onset of delamination occurred corresponded to the values obtained by performing a linear regression of the delaminated area, obtained by ultrasonic scanning, as a function of the impact force. Tensile and flexural tests performed on impacted specimens showed that the tensile and flexural residual strengths and the flexural modulus decreased with increasing incident impact energy, while the post‐impact residual tensile modulus remained constant. The dynamic interlaminar fracture toughness was evaluated from the critical dynamic (impact) strain energy release rate of specimens with a delamination simulated by an embedded insert. The results are compared with the interlaminar fracture toughness values obtained during subcritical steady crack growth.