bluuebunny/crossref_metadata_2025 huggingface dataset:
Monolayer versus aggregate balance in survival process for EGF‐induced apoptosis in A431 carcinoma cells: Implication of ROS‐P38 MAPK‐integrin α2β1 pathway
Authors: Morazzani Marie , de Carvalho Daniela Diogenes , Kovacic Herve , Smida‐Rezgui Sophia , Briand Claudette , Penel Claude
Published: April 2004

A431 cells escape EGF‐induced apoptosis by forming cell aggregates. We show that these clusters migrate and merge with neighboring ones, resulting in larger structures composed of a multilayer central (3D) population surrounded by a cell monolayer (2D). We found that after 48 hr of 10 nM EGF treatment, 3D structure formation correlates with α2β1 integrin upregulation. Blockade of α2 integrin impairs 3D structure formation. We studied the involvement of reactive oxygen species (ROS) in this process. We show that A431 cells express the NADPH oxidase catalytic subunits Nox1. EGF‐induced dose‐dependant ROS production was inhibited by the NADPH oxidase inhibitor, diphenylene iodonium (DPI), in these cells while rotenone was ineffective. Inhibition of ROS level in A431 cells with DPI or ebselen (glutathione peroxydase mimic) as well as P38 MAP kinase inhibition by SB203580 decreases α2 integrin subunit expression and induces a shift to 3D versus 2D populations. Cell cycle analysis of 2D cells shows that DPI, ebselen and SB203580 decrease the number of cells in S/G2 phase without affecting the cell number in mitosis phase. On the contrary, for 3D cells, these treatments increased the proportion of cells in mitosis without modification of the cell number in S/G2 phase. For both populations, apoptosis was increased by DPI and ebselen. Resistance of cell aggregates by paclitaxel to cell death is usually described. We show that DPI abolishes paclitaxel resistance of 3D cell aggregates. We observed a greater than additive effect between paclitaxel and DPI resulting in an increased proportion of cells in S/G2 phase for 3D populations. These results suggested that the ROS‐P38 MAP kinase‐α2β1 integrin pathway was implicated in the A431 survival process by modulating the balance between 2D/3D cells. © 2004 Wiley‐Liss, Inc.
Vacuum ultraviolet treatment of polyethylene to change surface properties and characteristics of protein adsorption
Authors: Vasilets Viktor N. , Kuznetsov Artem V. , Sevastianov Viktor I.
Published: April 2004

The effects of vacuum ultraviolet (VUV) treatment on surface chemical composition morphology and albumin adsorption for low‐density polyethylene (LDPE) and high‐density polyethylene (HDPE) were investigated. The attenuated total reflection‐Fourier transform infrared (ATR‐FTIR) spectra and contact angle measurements indicated the formation of oxygen‐containing polar groups and double bonds under VUV photooxidation in the presence of air or under VUV irradiation in vacuum. Scanning electron microscopy revealed the development of regular structure with the period about 1 μm on the surface of LDPE and HDPE during VUV photooxidation. The correlation between amount of tightly adsorbed albumin and surface concentration of carboxyl groups generated by VUV irradiation was found. The aging effect for protein adsorption during long storage of VUV irradiated samples in air or phosphate‐buffered saline (PBS) was studied. The obtained results prove the VUV irradiation provides a high potential to regulate protein adsorption on polymers for biomedical applications. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 428–435, 2004
Experimental assessment of new stent technologies: Validation of a comparative paired rabbit iliac artery study model
Authors: Robert R. , Rioufol G. , Finet G. , Cottin Y. , Tabib A. , Zeller M. , Wolf J. E. , Lievre M. , Bricca G.
Published: April 2004

Preventing coronary in‐stent restenosis is a major challenge for physicians and industry. To assess new stent technologies, a comparative paired iliac artery model in rabbits is proposed. One tubular stent was implanted in each external iliac artery in 12 rabbits (i.e., 24 stents). An artery overdilatation level of 20% was strictly observed. Restenosis was examined at 30 days by angiography, intravascular ultrasound (IVUS) examination, and histomorphometry. On quantitative angiography, the mean loss of angiographic diameter was 9.8 ± 4.4% in the right as compared to 9.3 ± 55% in the left artery (p = 0.75). On IVUS, the volume of intrastent neointimal proliferation was 26.6 ± 4.9 mm3 in the right and 25.8 ± 3.5 mm3 in the left artery (p = 0.58). In histomorphometry, the neointimal proliferation area was 0.78 ± 17 mm2 in the right and 0.76 ± 0.17 mm2 in the left artery (p = 0.87). Intrastent neointimal proliferation was comparable between the left and right arteries of all rabbits. The model has three main advantages: (1) arterial dilatation and thus arterial wall aggression are controlled, (2) pairing makes each animal its own control subject, and (3) the statistical power for comparative testing is maximized. The model enables the effect of a new drug‐delivery device to be assessed. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 303–310, 2004
Vascular graft healing. III. FTIR analysis of ePTFE graft samples from implanted bigrafts
Authors: Murray‐Wijelath Jacqueline , Lyman Donald J. , Wijelath Errol S.
Published: April 2004

A bigraft, composed of a 30‐μm internodal distance expanded polytetrafluoroethylene (ePTFE) arterial graft segment and a preclotted polyethylene terephthalate arterial graft segment, was used to study the healing process of two different materials in the same dog. Healing was followed by FTIR‐ATR spectroscopy and correlated with ELISA analyses of selected growth factors and matrix proteins. The FTIR analyses of the ePTFE explants from 1 and 3 h; 3, 5, 7, 10, and 14 days; and 4 and 8 weeks showed that the ePTFE grafts did not heal (endothelialize), but appeared to remain in overlapping inflammation and proliferation stages of wound healing. Although FN was found in the fibrin layer coating the luminal surface of the ePTFE, VEGF was not present. The inability of VEGF to complex with FN may be the result of FN binding sites being blocked or hidden by the conformation of the fibrin clot that forms on ePTFE. Also, TGF‐β was not present beyond the initial clot formation at 3 h postimplantation. The absence of these two growth factors may be an important factor in the lack of healing of 30‐μm ePTFE grafts, because both were found to be present during the early stages of healing for the preclotted polyester grafts that did endothelialize. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 223–232, 2004
Improved model core potentials for the second‐ and third‐row transition metals
Authors: Lovallo Christopher C. , Klobukowski Mariusz
Published: April 2004

New nonrelativistic and scalar‐relativistic pseudopotentials for the second‐ and third‐row transition metals have been developed. These improved Model Core Potentials were used in calculations for a variety of transition metal complexes to test their ability to reproduce experimental structures and vibrational frequencies. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1206–1213, 2004
MT1‐MMP: A tethered collagenase
Authors: Holmbeck Kenn , Bianco Paolo , Yamada Susan , Birkedal‐Hansen Henning
Published: April 2004

Gene ablation in mice offers a powerful tool to assay in vivo the role of selected molecules. Numerous new mouse models of matrix metalloproteinases (MMP) deficiency have been developed in the past 5 years and have yielded a new understanding of the role of MMPs while also putting to rest assumptions based on data predating the days of mouse models. The phenotype of the MT1‐MMP deficient mouse is one example which illustrates the sometimes rather surprising insights into extracellular matrix remodeling in development and growth that can be gained with mouse genetics. While MT1‐MMP appears to play little or no role in embryonic development, loss of this enzyme results in progressive impairment of postnatal growth and development affecting both the skeleton and the soft connective tissues. The underlying pathologic mechanism is loss of an indispensable collagenolytic activity, which remains essentially uncompensated. Our findings demonstrate that growth and maintenance of the skeleton requires coordinated and simultaneous MT1‐MMP‐dependent remodeling of all soft tissue attachments (ligaments, tendons, joint capsules). We note that the phenotype of the MT1‐MMP deficient mouse bears no resemblance to those of mice deficient in MMP‐2 and tissue inhibitors of metallo‐proteinase (TIMP)‐2 all but dispelling the view that activation of MMP‐2 by the MT1‐MMP/TIMP‐2/proMMP‐2 axis plays a significant role in growth and development throughout life. It is of interest to note that loss of a single catabolic function such as selective collagen degradation mediated by MT1‐MMP gives rise to profound impairment of a number of both anabolic and catabolic functions. © 2004 Wiley‐Liss, Inc.
Unusual sonographic appearance of a gastrointestinal stromal tumor presenting as a large multilocular cystic mass
Authors: Chang Chi‐Yang , Wang Hsiu‐Po , Mao Tasui‐Lien , Hu Rey‐Heng , Yang Pei‐Ming , Lai Ming‐Yang , Lin Jaw‐Town
Published: April 2004

Cystic change is uncommon in gastrointestinal stromal tumor, (GISTs). This report describes 1 case in which a GIST presented as a large multilocular cystic mass. Sonography of the abdomen showed a huge cystic lesion with multiple septa in the left upper quadrant of the abdomen, compressing the left lobe of the liver. Esophagogastroscopy showed only a small submucosal tumor at the anterior wall of the mid portion of the gastric body. Endoscopic sonography revealed a hypoechoic mass, measuring 0.9 × 0.7 cm, arising from the fourth layer of the anterior wall of the mid portion of the gastric body. A huge cystic tumor, containing multiple septa and continuous with the small submucosal lesion, was found. Doppler signals were detected within the septa. Laparotomy revealed a huge exophytic cystic tumor arising from the stomach. Immunohistochemical analysis confirmed that the lesion was a GIST by detecting expression of the c‐kit and CD34 proteins. GIST that has undergone cystic change must be differentiated from other cystic lesions to guide the treatment approach. Imatinib mesylate is a new therapeutic alternative for patients who have advanced GIST, but surgery remains the therapy of choice for resectable disease. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:200–203, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jcu.20010
Contrast‐enhanced power Doppler sonography of ductal pancreatic adenocarcinomas: Correlation with digital subtraction angiography findings
Authors: Chen Chien‐Hua , Yang Chi‐Chieh , Yeh Yung‐Hsiang , Huang Min‐Ho
Published: April 2004

Purpose

The purpose of this prospective study was to utilize contrast‐enhanced power Doppler sonography to evaluate the enhancement characteristics of ductal pancreatic adenocarcinomas and correlate them with the tumor vascularity observed on digital subtraction angiography (DSA).

Methods

Twenty consecutive patients with ductal pancreatic adenocarcinoma underwent power Doppler sonography and DSA. Tumor vascularity was assessed using unenhanced and contrast‐enhanced power Doppler sonography. The contrast agent Levovist was administered intravenously by bolus injection of a dose of 2.5 g at a concentration of 350 mg/mL; saline was administered immediately thereafter. The patients were asked to hold their breath for 30 seconds (for the period 15–45 seconds after saline injection) while the early phase of enhancement was studied; the delayed phase of enhancement was observed between 60 and 120 seconds after saline administration, while patients breathed gently.

Results

None of the 20 pancreatic carcinomas showed any color signals on power Doppler sonography before administration of the contrast medium. Seventeen (85%) of the 20 pancreatic carcinomas also showed no enhancement in the early and delayed phases of contrast‐enhanced power Doppler sonography. However, in the early phase of contrast‐enhanced power Doppler sonography; 1 lesion showed pronounced enhancement and 2 showed mild enhancement. On DSA, the 17 carcinomas showing no enhancement on power Doppler sonography were found to be hypovascular, whereas the remaining 3 carcinomas with contrast enhancement on power Doppler sonography were found to be hypervascular.

Conclusions

The enhancement characteristics of the ductal pancreatic adenocarcinomas correlated well with the tumor vascularity observed on DSA. However, further study is needed to determine the accuracy of contrast‐enhanced sonography in the diagnosis of pancreatic masses. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:179–185, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jcu.20018
Unusual hepatic‐portal‐systemic shunting demonstrated by Doppler sonography in children with congenital hepatic vein ostial occlusion
Authors: Barakat Maha
Published: April 2004

Purpose

This report describes unusual changes in the hepatic vasculature in 3 children presenting with upper gastrointestinal hemorrhage.

Methods

The study included 3 children (ages 5–8 years) who presented with hematemesis. All had mild hepatosplenomegaly and normal liver function. Esophageal varices were demonstrated in all on upper endoscopy. Color and spectral Doppler sonography was performed to assess the hepatic vasculature, including the hepatic veins (HVs), portal vein (PV), hepatic artery (HA), and inferior vena cava (IVC).

Results

The HVs were all patent but with ostial occlusion at the point of their communication with the IVC. Complete flow reversal was shown inside the HVs, with blood draining into collateral vessels at the liver surface and paraumbilical vein. In one patient, the paraumbilical vein could be traced to its communication with the right external iliac vein. In all children, the direction of flow in the PV, HA, and IVC was normal. After endoscopic sclerotherapy, all children were shown to be in good general condition and to have normal liver function for a follow‐up period of 15–36 months.

Conclusions

Ostial occlusion of the HV is a rare cause of hepatic outflow obstruction in children. Doppler sonography is a valuable, noninvasive imaging technique for evaluation of the hepatic vasculature and the accompaning shunting pathways in such cases. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:172–178, 2004; Published online in Wiley InterScience (www. interscience.wiley.com). DOI: 10.1002/jcu.20019
Influence of packaging material on pomegranate juice colour and bioactive compounds, during storage
Authors: Pérez‐Vicente A , Serrano P , Abellán P , García‐Viguera C
Published: April 2004

Pomegranate juices were assessed after pasteurisation and storage in different packaging materials: transparent and green glass, and paperboard carton with polyethylene layers (Minibrik‐200). The main objective was to establish the influence of the container on the stability of colour and bioactive compounds (anthocyanins, ellagic acid and other non‐coloured phenols). Results showed that non‐coloured phenols and ellagic acid were quite stable during the storage period. In contrast, anthocyanins degraded, to an extent directly proportional to colour loss, less for those juices stored in glass bottles than for those stored in Minibrik. These results indicated that these paperboard carton containers are oxygen permeable, and that oxygen has a greater influence on anthocyanin, and consequently on colour degradation, than light on pomegranate juice during storage. Nevertheless, the antioxidant activity was not influenced by the packaging material employed. Copyright © 2004 Society of Chemical Industry
Screening of oxazepine indole enantiomers by means of high performance liquid chromatography with imprinted polymer stationary phase
Authors: Machtejevas Egidijus , Sellergren Börje , Martynaitis Vytas , Owens Paul K. , Maruška Audrius
Published: April 2004

Chromatographic enantiomer separations of different oxazepine indole derivatives were performed using a molecularly imprinted polymer. A 5aR,12R,13S‐trans‐6,6‐dimethyl‐12,13‐dihydro‐6H‐5a,13‐methanoindolo[2,1‐b][1,3]naphthoxazepine‐12‐carboxamide enantiomer derivative was used as a template and the resultant polymer has shown enantiomer recognition for series of template related compounds. The mechanistic description of the chiral discrimination process is scrutinised, comparing the discrimination between the different conformations and substituents of the oxazepine indoles.
Chiroptical Properties of Terthiophene Chromophores Dispersed in Oriented and Unoriented Polyethylene Films
Authors: Pucci Andrea , Nannizzi Silvia , Pescitelli Gennaro , Di Bari Lorenzo , Ruggeri Giacomo
Published: April 2004

Summary: Two new chiral terthiophene chromophores II and III were prepared with 99% enantiomeric excess. Chiroptical properties of these dyes dispersed in ultra high molecular weight polyethylene (UHMWPE) films were determined and compared with the same properties in solution. In the solid state, the optical activity strongly depends on the interaction mechanisms within small crystalline aggregates of chromophores. The film morphology and chromophore dispersion were also investigated by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The good correlation between chromophore aggregation and chiroptical activity of the binary films promotes circular dichroism (CD) as an effective technique for monitoring the phase dispersion behaviour of dichroic dyes into polymer matrices. By mechanical stretching of the film a linearly dichroic orientation of the chromophores is obtained which results in a high degree of linear dichroism. The influence of the uniaxial orientation of terthiophene molecules along the drawing direction of UHMWPE on the chiroptical properties of the films, and the possible application of the oriented devices as linear polarizers are discussed.

Absorption and CD spectra of unoriented UHMWPEII film at different rotation angles θ.

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Absorption and CD spectra of unoriented UHMWPEII film at different rotation angles θ.
Novel Biodegradable Aliphatic Polycarbonate Based on Ketal Protected Dihydroxyacetone
Authors: Wang Lian‐Sheng , Cheng Si‐Xue , Zhuo Ren‐Xi
Published: April 2004

Summary: A novel aliphatic polycarbonate based on ketal protected dihydroxyacetone was synthesized by ring‐opening polymerization of cyclic carbonate monomer, 2,2‐ethylenedioxypropane‐1,3‐diol carbonate (EOPDC), in bulk. Effects of polymerization conditions such as catalysts, catalyst concentration, reaction temperature and reaction time on the polymerization were investigated. The polycarbonate obtained was characterized by GPC, FTIR, 1H NMR, 13C NMR and DSC. The study on in vitro degradation of PEOPDC shows that the degradation mainly results from surface erosion.

Synthesis of an aliphatic polycarbonate with a high molecular weight by ring‐opening polymerization of cyclic carbonate monomer EOPDC.

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Synthesis of an aliphatic polycarbonate with a high molecular weight by ring‐opening polymerization of cyclic carbonate monomer EOPDC.
Tremor induced by thalamic deep brain stimulation in patients with complex regional facial pain
Authors: Constantoyannis Constantine , Kumar Ajit , Stoessl A. Jon , Honey Christopher R.
Published: April 2004

We report on two patients who developed a new postural and action tremor after chronic stimulation of the contralateral thalamus (VPM nucleus) during treatment of a complex regional facial pain syndrome. The tremor was only present during deep brain stimulation (DBS) and was suppressed with adjustment of the stimulation parameters. Tremor was seen only with low frequency stimulation (50 Hz or lower) and disappeared with higher stimulation frequencies. In addition to being an unusual side effect of thalamic DBS, we believe that this phenomenon affords insight into one possible mechanism underlying essential tremor (ET). A central oscillatory mechanism involving the olivocerebellar complex and the thalamus, which is a part of the cerebro–cerebello–cerebral circuit, is thought to play an important role in the genesis of ET. Induction of a tremor resembling ET in our patients indicates an active role for low frequency stimulation. A plausible explanation for this is that low frequency stimulation in the thalamic area enhances the output of the tremor‐producing network. This leads credence to the concept of central oscillations in a “tremor circuit,” of which the thalamus is a part, as being important in ET. © 2004 Movement Disorder Society
Wide expressivity variation and high but no gender‐related penetrance in two dopa‐responsive dystonia families with a novel GCH‐I mutation
Authors: Uncini Antonino , De Angelis Maria Vittoria , Di Fulvio Patrizia , Ragno Michele , Annesi Grazia , Filla Alessandro , Stuppia Liborio , Gambi Domenico
Published: April 2004

We describe the clinical and molecular correlates in two Italian families with dopa‐responsive dystonia (DRD) and the same novel mutation of GTP‐cyclohydrolase I (GCH‐I) gene. Thirty‐five subjects were examined and the genotype correlated to phenotype. Childhood onset foot dystonia is present in 7 subjects currently under the age of 40. In 1 patient bilateral foot dystonia was evident at birth suggesting that dystonia may be active as early as in utero. In another patient, dystonia spontaneously remitted in adolescence, to relapse 8 years later, as writer's cramp. Dystonia and parkinsonian signs are present in 5 other patients. In 2 subjects an isolated parkinsonism started over the age of 45. A 5‐base pair insertion at codon 242 within exon 6 of GTP‐cyclohydrolase I (GCH‐I) gene that shifts the reading frame and results in a premature stop at codon 247 with truncation of the polypeptide has been detected in 21 subjects. Considering dystonia and parkinsonism the overall penetrance is 0.71 and not significantly different in men (0.69) and women (0.75). Genealogical studies seem to exclude that these families are related but haplotype analysis suggests a single founder. Our findings in subjects with the same mutation indicate a wide intrafamilial variation in expressivity and high penetrance in DRD but do not confirm the reported influence of gender on GCH‐I gene mutation penetrance. © 2004 Movement Disorder Society
Differences in age at onset and familial aggregation between clinical types of idiopathic Parkinson's disease
Authors: Korchounov Alexei , Schipper Hayo I. , Preobrazhenskaya Irina S. , Kessler Kirn R. , Yakhno Nikolay N.
Published: April 2004

Idiopathic Parkinson's disease (PD) can be subdivided by its patterns of motor symptoms into tremor‐dominant (TDT), akinetic‐rigid (ART), and mixed type (MT). Our objective was to determine whether age at onset and family history are different in these three types. In total, 366 patients with PD were assigned in a standardized approach to one of the three subtypes. Age at onset and family history were obtained in all patients and all presumably affected family members were examined. Mean ages at disease onset were similar in all three groups, but distribution of age at onset was markedly different: monophasic in TDT with a peak around 60 years, biphasic in ART with two peaks, one in the middle of the sixth decade (earlier onset, ART‐EO), another during the first half of the seventh decade (later onset, ART‐LO), and increasing with age only in MT patients A positive family history was significantly associated only with TDT (odds ratio = 5.7) and ART‐EO (odds ratio = 7.8), but not with MT or ART‐LO patients. Segregation analysis suggested an autosomal recessive mode of transmission in ART‐EO and an autosomal dominant mode of transmission in TDT. © 2004 Movement Disorder Society
GIAO/DFT evaluation of 13C NMR chemical shifts of selected acetals based on DFT optimized geometries
Authors: Migda Wojciech , Rys Barbara
Published: April 2004

DFT/B3LYP calculations of the ground‐state conformation of eight cyclic and acyclic acetals are presented and compared with experimental data. Results of single‐point GIAO/DFT calculations at five different levels of theory show that isotropic shieldings need to be empirically scaled to achieve agreement with experimental chemical shifts. Statistical evaluation of data indicates that the most accurate prediction of 13C chemical shifts is achieved at the MPW1PW91/6–311G** level of theory. An empirical equation describing the relationship between δ values and shielding constants is postulated. This equation has been applied to the non‐chair ground‐state conformation of the six‐membered acetonide and to the conformationally flexible benzodioxonine derivative. The agreement observed between the experimental and predicted chemical shifts shows that calculations at the MPW1PW91/6–311G** level of theory are adequate for addressing questions of conformation. Copyright © 2004 John Wiley & Sons, Ltd.
Multinuclear magnetic resonance and molecular modeling investigations as unambiguous methods for the determination of silacycle 3D structures
Authors: Mahieux Cédric , Laguerre Michel , Landais Yannick , Pianet Isabelle
Published: April 2004

An unexpected six‐membered silacycle was obtained using ring‐closing metathesis of diallylsilane 3. The ring size of the compound formed was derived using a 2D 13C–13C inadequate experiment. All proton and carbon‐13 resonances were assigned from classical 2D NMR experiments and the proton coupling pattern was clarified. Molecular modeling calculation was then applied using NMR data as constraints, giving the 3D structure of the synthesized compound. Copyright © 2004 John Wiley & Sons, Ltd.
The influence of the depth of the ground water table on free field road traffic‐induced vibrations
Authors: Schevenels M. , Degrandec G. , Lombaert G.
Published: April 2004

This paper describes the influence of seasonal variations of the ground water table on free field traffic‐induced vibrations. The passage of a truck on two types of road unevenness is considered: a joint in a road pavement consisting of concrete plates and a speed bump with a sinusoidal profile. Free field vibrations are computed with a two‐step solution procedure, where the computation of the vehicle axle loads is decoupled from the solution of the road–soil interaction problem. The impedance of the soil is calculated using a boundary element method, based on the Green's functions for a dry layer on top of a saturated half‐space. It is demonstrated that, in the low‐frequency range of interest, wave propagation in the saturated half‐space can be modelled with an equivalent single phase medium as an alternative to Biot's poroelastic theory for saturated porous media. The relation between the free field velocity and the depth of the ground water table is dominated by three phenomena: (1) the compressibility of the soil decreases due to the presence of the pore water, (2) the ground water table introduces a layering of the soil which may cause resonance of the dry layer and (3) refracted P‐waves in the dry layer interfere with surface waves. If the depth of the ground water table is large with respect to the wavelength of the vibrations in the soil, the response tends to the response of a dry half‐space. The average free field velocity is equal to the velocity in the absence of ground water. If the depth of the ground water table is small with respect to the wavelength of the vibrations in the soil, the response tends to the response of a saturated half‐space and resonance of the dry layer does not occur. The average free field velocity is smaller than the velocity in the absence of ground water. The interference of refracted P‐waves and surface waves causes an additional oscillation of the response as a function of the excitation frequency and the distance between the road and the receiver. Copyright © 2004 John Wiley & Sons, Ltd.
Crack propagation analysis with Galerkin boundary element method
Authors: Xu K. , Lie S. T. , Cen Z.
Published: April 2004

This paper describes the application of symmetric Galerkin boundary element methods (SGBEM) for the analysis of a 2D crack propagation problem. The sub‐domain SGBEM for crack problem is derived. The coefficient matrix is completely symmetric. Cohesive crack model is used to simulate crack propagation. The increment control method for crack propagation and the method for unknown crack propagation path have been derived for high‐order element. Two‐stage interpolation method called the ‘quasi‐higher order element method’ (QHOEM) is then proposed to solve the double integrals. In the initial stage, it uses higher order elements to interpolate the field variables, and for the numerical integration involved, it further uses interpolation functions to decompose the higher order elements into lower order elements so that the existing analytical integration can be applied. A finite rectangular plate containing a centre crack growth and four‐points bending beam problem have been analysed to check the accuracy of the proposed method. For actual application, a dam buttress with an edge crack has been analysed and the results are found to be in agreement with the other numerical and experimental results. Copyright © 2004 John Wiley & Sons, Ltd.
Deformations resulting from the movements of a shear or tensile fault in an anisotropic half space
Authors: Sheu Guang Y.
Published: April 2004

Earlier solutions (Bull. Seismol. Soc. Amer. 1985; 75:1135–1154; Bull. Seismol. Soc. Amer. 1992; 82:1018–1040) of deformations caused by the movements of a shear or tensile fault in an isotropic half‐space for finite rectangular sources of strain nucleus have been extended for a transversely isotropic half‐space. Results of integrating previous solutions (Int. J. Numer. Anal. Meth. Geomech. 2001; 25(10): 1175–1193) of deformations due to a shear or tensile fault in a transversely isotropic half‐space for point sources of strain nucleus over the fault plane are presented. In addition, a boundary element (BEM) model (POLY3D:A three‐dimensional, polygonal element, displacement discontinuity boundary element computer program with applications to fractures, faults, and cavities in the Earth's crust. M.S. Thesis, Stanford University, Department of Geology, 1993; 62) is given. Different from similar researches (e.g. Thomas), the Akaike's view on Bayesian statistics (Akaike Information Criterion Statistics. D. Reidel Publication: Dordrecht, 1986) is applied for inverting deformations due to a fault to obtain displacement discontinuities on the fault plane.

An example is given for checking displacements predicted by proposed analytical expressions. Another example is generated for the use of proposed BEM model. It demonstrates the effectiveness of this model in exploring displacement behaviours of a fault. Copyright © 2004 John Wiley & Sons, Ltd.
Excretion of collagen derived peptides is increased in women with stress urinary incontinence
Authors: Kushner Leslie , Mathrubutham Mahesh , Burney Tracey , Greenwald Robert , Badlani Gopal
Published: April 2004

Aims

The objective of this study was to demonstrate that weakened pelvic floor support of the lower genitourinary tract in women with stress urinary incontinence (SUI) is due to increased collagenolysis. When fibrillar collagen is degraded, pyridinium (PYD) crosslinks are released and excreted in the urine. Degradation of collagen also results in peptide fragments of various lengths which are excreted in the urine. Degradation of mature fibrillar collagen and collagen which has not been crosslinked can be assessed independently by measurement of both PYD and collagen‐derived peptides in the urine.

Methods

Twenty‐four hour urine collections were obtained from women with SUI (n = 23) and women without urinary incontinence (n = 39). Urinary PYD concentration was assayed by ELISA. The urinary concentration of helical peptide α1 (I) 620–633 fragments derived from collagen was assayed by competitive enzyme immunoassay. Values were normalized to creatinine.

Results

The mean urine PYD concentration for women with SUI (110.8 ± 19.7 nM/mM creatinine) was not significantly different than that for women without SUI (85.2 ± 13.7 nM/mM creatinine). The mean urine concentration of helical peptide α1 (I) 620–633 for women with SUI (0.80 ± 0.13 μg/mg creatinine) was significantly (P < 0.02) higher than that for women without SUI (0.49 ± 0.06 μg/mg creatinine).

Conclusions

These data suggest that collagenolytic activity in women with SUI is elevated compared to continent controls, as measured by urinary helical peptide α1 (I) 620–633 excretion. The lack of difference in urinary PYD excretion between the two populations suggests that the increased collagenolytic activity in women with SUI, compared to continent controls, is restricted to uncrosslinked collagen. Neurourol. Urodynam. 23:198–203, 2004. © 2004 Wiley‐Liss, Inc.
Reliability, validity, and gender differences in the quality of life index of the SEAPI‐QMM incontinence classification system
Authors: Stothers Lynn
Published: April 2004

Purpose

To evaluate reliability and validity of the SEAPI‐QMM 15‐item quality of life index and assess differences between male and female patients with urinary incontinence.

Materials and Methods

Twice pre‐ and once post‐treatment, 315 patients (102 men, 213 women) with incontinence and 35 without incontinence completed the self‐directed SEAPI‐QMM quality of life index. A voiding diary reported frequency of incontinence episodes with number of pads or type of protection used daily for incontinence. In 30%, the Nottingham Health Profile (NHP) was administered to further validate the measure.

Results

Cronbach's alpha coefficient for the index was 0.91. Domain‐specific alpha coefficients ranged from 0.88 to 0.73. Test‐retest reliability scores at 5 days gave a reliability coefficient of 0.93. Split half reliability was 0.89. Correlation of the index with the NHP was 0.78 for women, 0.72 for men. Mean scores before and after treatment with medical or surgical management were significantly different in both genders and were sensitive to the presence or absence of use of protection and the type of protection chosen in men. Men with incontinence (61%) reported a high level of impact in the sexuality domain compared to 7% of women.

Conclusions

The SEAPI quality of life index has a high degree of reliability relating to stability and internal consistency across a wide age range in both genders. There are differences between men and women in life domains most frequently affected by urinary incontinence. Neurourol. Urodynam. 23:223–228, 2004. © 2004 Wiley‐Liss, Inc.
Course and clinical impact of magnetic resonance imaging findings in diabetes insipidus associated with Langerhans cell histiocytosis
Authors: Grois Nicole , Prayer Daniela , Prosch Helmut , Minkov Milen , Pötschger Ulrike , Gadner Helmut
Published: April 2004

Background

Diabetes insipidus (DI) is the most frequent sequela in Langerhans cell histiocytosis (LCH). The clinical relevance and therapeutic impact of brain magnetic resonance imaging (MRI) findings in LCH patients with LCH during the disease course is unclear.

Procedure

In this retrospective study, we reviewed 113 brain MRIs from 59 DI patients, in 17 of these serial follow up MR‐examination findings were correlated to the clinical course and therapy.

Results

At DI diagnosis, 71% patients showed a thickened stalk, in 24% the stalk was still thickened on MRIs done more than 5 years after DI onset, and in two patients the stalk was already thickened several months before DI onset. The changes of the pituitary stalk thickness were highly variable and did not clearly correlate with the treatment. Regression of pituitary thickness on MRI did not concur with clinical recovery of DI, which persisted in all but one patient with initially partial DI. The occurrence of anterior pituitary hormone deficiencies appeared to be linked to a thickening of the stalk at DI diagnosis. LCH‐lesions in the craniofacial bones were seen in 75% DI patients, and 76% of DI patients with follow up MRIs done 5 years or longer after DI diagnosis had parenchymal neurodegenerative brain changes.

Conclusions

Our study indicates that repeated MR‐examinations in DI patients are of limited value for assessing a response to therapy in the pituitary stalk, but are important for the monitoring of craniofacial bone lesions and for the detection of parenchymal CNS disease. © 2004 Wiley‐Liss, Inc.
Stiffness and toughness of polypropylene/glass bead composites
Authors: Kwok K. W. , Gao Z. M. , Choy C. L. , Zhu X. G.
Published: April 2004

The effects of coupling effect, particle diameter (d), volume fraction (Vb) and size distribution (σ) of glass beads on the impact strength and tensile modulus of polypropylene (PP)/glass bead composites have been investigated. The toughness and stiffness of the composite can be simultanously enhanced by using a titanate coupling agent, which gives rise to a moderate interfacial adhesion (characterized by an interaction parameter B ∼ 1) between the glass beads and the matrix. With the addition of this coupling agent, the impact strength of the PP/glass bead composite with d = 2.7 μm and σ = 1.85 increases about 4.5 times as Vb increases from 0 to 0.25, while the tensile modulus remains roughly unchanged. For the composites with larger d and narrower size distribution, the impact strength increases only slightly with increasing Vb. The combined effect of d, Vb and size distribution of the glass beads are described by using a single parameter, the average matrix ligament thickness T. Unlike rubber‐modified polymers, the impact strength of PP/glass bead composites does not follow a master curve when plotted against T.
A model for the transverse permeability of bi‐material layered fibrous preforms
Authors: Markicevic B. , Papathanasiou T. D.
Published: April 2004

We consider viscous flow across unidirectional hexagonal arrays of porous tows of elliptical cross section. Using the lubrication approximation we develop an analytical model for the hydraulic permeability of layered systems, in which the permeability of the porous tows making up each alternating layer is allowed to differ. Extensive validation of this model is carried out through numerical computations using the Computational Fluid Dynamics package FIDAP. Good agreement between model predictions and numerically calculated permeabilities is found in the interesting region of small porosity (ϕ = 0.20 or ϕ = 0.30). Using this model we also address the issue of the inaccuracies that may be introduced if the overall permeability of a fibrous preform is calculated using an arithmetic average permeability instead of the actual permeability of each layer. We find that use of an average permeability will result in overestimation of the overall permeability of the system. This overestimation will increase as the porosity is reduced and/or as the difference in permeabilities increases.
Studies in interchain crosslinking and heat shrinkability of polymer blends consisting of grafted low‐density polyethylene and ethylene‐acrylic rubber
Authors: Mishra J. K. , Das C. K.
Published: April 2004

Blends prepared by the melt mixing of thermoplastic and elastomer have gained considerable attention in recent years. Heat shrinkability, which is dependent on elastic memory, can be introduced into the system in the form of an elastomeric phase. The present study deals with the measurement of heat shrinkability of the blends of grafted polyethylene and an ethylene acrylic elastomer. Interchain crosslinking between grafted polyethylene and elastomer improves the shrinkability. High temperature performance of the samples depends on interchain crosslinking. From torque rheometry it was observed that the maximum amount of interchain crosslinking was obtained in the sample containing acrylamide grafted LDPE. The probable interaction between the rubber and the plastic phase is confirmed by IR spectroscopy.
Static deformation of low structure HAF black‐loaded (SBR+NR) rubber blend
Authors: El‐Lawindy A. M. Y.
Published: April 2004

The stress‐strain behavior of different concentrations of low‐structure high abrasion furnace black (HAF‐LS, N326)‐loaded rubber blend of styrene butadiene rubber and natural rubber (SBR+NR) of equal parts was measured. Moduli of elasticity and the n‐measure of such blends were calculated using different approaches. An anomaly, of modulus of elasticity, found at 50 phr may be attributed to carbon black reinforcement and to an early crystallization of stretched natural rubber (NR) in the blend. These assumptions are confirmed through the measurement of the swelling factor as a function of time of swelling in kerosene.
The influence of matrix chemical structure on the mode I and II interlaminar fracture toughness of glass‐fiber/epoxy composites
Authors: Álvarez Vera , Bernal Celina R. , Frontini Patricia M. , Vázquez Analia
Published: April 2004

The present paper is concerned with Mode I and Mode II delamination tests performed on three different glass fiber reinforced epoxy composites, chosen to obtain different final structures. The effect of crosshead speed on the fracture resistance of the composites was also analyzed. It was found that Mode I propagation values (GIC) increase as the crosshead speed decreases, probably because of the increase of brittleness in the studied range. An Arrhenius type relation between GIC and the glass transition temperature of the epoxy resin/amine system (Tg) was found. Mode II initiation values (GIICinit) and apparent shear strength (SH) were found to increase with the decrease of Tg. The relation between matrix toughness and composite interlaminar fracture toughness was also considered. Finally, the GIC propagation values were compared to the data available in literature for similar materials.
Simultaneous optimization of die‐heating and pull‐speed in pultrusion of thermosetting composites
Authors: Jianhua Li Y. C. Lam , Joshi Sunil C.
Published: April 2004

Die‐temperature and pull‐speed are the key parameters in pultrusion that affect the degree and uniformity of the curing of thermosetting composites, which in turn influence their mechanical properties and in‐service performance. This paper presents the development, implementation, and validation of a numerical procedure for arriving at an optimum combination of die‐heater temperatures and pull‐speed for producing a uniformly cured composite pultrudate. An objective function representing the effects of both parameters on the distribution of degree‐of‐cure across the cross section of a pultruded part at the die exit was established. The function was used to develop an algorithm for calculating the required changes in die‐heater temperatures and pull‐speed to achieve a desirable degree‐of‐cure with maximum possible uniformity. The algorithm was implemented using the three‐dimensional. Finite Element/Nodal Control Volume (FE/NCV) approach for process simlation, in which a general‐purpose FE package was used to perform heat transfer analysis, together with other routines developed to perform cure modeling and the optimization. The application of the developed procedure was demonstrated by simulating pultrusion of a graphite/epoxy C‐section. The results of the studies show that the procedure is numerically stable and works well for a die with multiple heaters.
Pore network modeling of permeability for textile reinforcements
Authors: Delerue J.‐F. , Lomov S. V. , Parnas R. S. , Verpoest I. , Wevers M.
Published: April 2004

The homogenized permeability of textile reinforcement is computed using pore network modeling. The model takes as input a 3D image of the reinforcement, reduced to an array of points, each of them having a binary value designating whether the point lies inside a yarn or in a pore. The array can be acquired by X‐ray micro‐computerized tomography. The calculations proceed in two steps. First, the 3D image is analyzed to create a representation of the pores in the reinforcement by a system of interconnected pipes. Each pipe is characterized by its hydraulic resistance. Then the hydraulic resistance of the system of pipes is computed using the Kirchoff theory to yield a value for homogenized permeability of the reinforcement. The model is applied to a glass woven laminate, producing results in good agreement with experimentally measured values.
The role of the interaction coefficient in the prediction of the fiber orientation in planar injection moldings
Authors: Pontes A. J. , Neves N. M. , Pouzada A. S.
Published: April 2004

The mechanical properties of injection molded parts in glass reinforced materials are sensitive to processing. A successful design requires a good estimate of the product performance before production. Its performance is strongly affected by the fiber orientation field set up during processing. The fiber orientation pattern is complex and varies three‐dimensionally in the moldings. Some commercial simulation programs already allow the prediction of the fiber orientation induced during the flow by the associated stress field. The results from the simulations are dependent on a parameter accounting for the interactions between fibers during the flow, known as the fiber interaction coefficient. In this paper the effectiveness of the interaction parameter on controlling the predicted patterns of the fiber orientation is studied. This is done by comparing and analyzing the experimental data and the corresponding predictions.
Identification of fiber misalignment in continuous fiber composites
Authors: Barwick S. C. , Papathanasiou T. D.
Published: April 2004

Misaligned fibers are invariably present in nominally unidirectional high‐performance composites. Such misaligned fibers are known to affect key mechanical properties of the composite, such as the longitudinal compressive strength, longitudinal tensile modulus, fatigue endurance, shear strength, and delamination resistance (1). In this paper we present a method for the automated detection of large angle fiber misalignment (θ > 40°) in continuous fiber‐reinforced composite materials. The method relies on the application of a series of geometrical criteria based upon measurements routinely obtained during optical scanning of polished sample cross‐sections. As such, the technique is ideal for the automated identification of highly misaligned fibers in large‐area (∼ cm2) specimens that may contain several millions of individual fiber images. The criteria applied take into account the fact that prepared cross‐sections of such materials contain many damaged fibers as a result of attrition during polishing. Data obtained from three pultruded unidirectional rods reinforced with continuous carbon filaments are used to illustrate the effectiveness of this method in identifying regions where large angle misalignment occurs.