bluuebunny/crossref_metadata_2025 huggingface dataset:
Hepatitis C virus non‐structural protein 4 suppresses Th1 responses by stimulating IL‐10 production from monocytes
Authors: Brady Miriam T. , MacDonald Angus J. , Rowan Aileen G. , Mills Kingston H. G.
Published: November 2003

The majority of hepatitis C virus (HCV) infections become chronic, despite the presence of HCV‐specific cellular and humoral immune responses. We have previously suggested that IL‐10‐secretingantigen‐specific regulatory T cells may contribute to viral persistence, and demonstrate here that peripheral blood mononuclear cells (PBMC) from chronically HCV‐infected patients secrete IL‐10, but not IFN‐γ, in response to HCV nonstructural protein 4 (NS4). A neutralizing anti‐IL‐10 antibody restored this defective antigen‐specific IFN‐γ production in vitro. Furthermore, PBMC from normal individuals secreted IL‐10 in response to NS4, suggesting that cells of the innate immune system, in addition to T cells, produced IL‐10 in the HCV‐infected patients. Cell separation experiments revealed that the innate IL‐10 was produced by blood monocytes, but not dendritic cells (DC). In addition, NS4 inhibited IL‐12 production by PBMC in response to LPS and IFN‐γ, and Th1 responses to recall antigens in normal individuals. Furthermore, supernatants from NS4‐stimulated monocytes inhibited LPS‐induced maturation of DC and suppressed their capacity to stimulate proliferation and IFN‐γ production by allospecific T cells. Our data suggest that HCV subverts cellular immunity by inducing IL‐10 and inhibiting IL‐12 production by monocytes, which in turn inhibits the activation of DC that drive the differentiation of Th1 cells.
Age‐related defects in CD4+ T cell activation reversed by glycoprotein endopeptidase
Authors: Garcia Gonzalo G. , Miller Richard A.
Published: November 2003

CD4+ T cells from old mice show defects in the activation process including deficiency in the formation of immunosynapses with antigen‐presenting cells. We show that CD4+ T cells from old mice express unusually high levels of glycosylated forms of the bulky T cell glycoprotein CD43, particularly on a subset of functionally anergic cells expressing P‐glycoprotein. T cells from old donors also show a decline in the association of CD43 with cytoskeletal matrix and in the proportion of T cells that can exclude CD43 from the synapse. O‐sialoglycoprotein endopeptidase, which removes the external domain of CD43 and other O‐sialoglycoproteins from the aged naive CD4+ T cells of TCR‐transgenic mice, restores early agonist‐independent stages and later agonist‐dependent stages of synapse formation as well as expression of the activation markers CD69 and CD25 to the levels found in the young mice. These data support a model in which O‐glycosylated forms of T cell surface molecules, including CD43, are largely responsible for age‐related defects in TCR signaling and function.
Lithium Perchlorate‐Catalyzed Three‐Component Coupling: A Facile and General Method for the Synthesis of α‐Aminophosphonates under Solvent‐Free Conditions
Authors: Azizi Najmedin , Saidi Mohammad R.
Published: November 2003

A simple, efficient, and general method has been developed for the synthesis of α‐aminophosphonates in the presence of solid lithium perchlorate under solvent‐free conditions. Thus secondary and tertiary α‐aminophosphonates were synthesized relatively quickly in good yields at room temperature. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Molecular mechanisms underlying IGF‐I‐induced attenuation of the growth‐inhibitory activity of trastuzumab (Herceptin) on SKBR3 breast cancer cells
Authors: Lu Yuhong , Zi Xiaolin , Pollak Michael
Published: November 2003

The clinical usefulness of trastuzumab (Herceptin; Genentech, San Francisco, CA) in breast cancer treatment is limited by the rapid development of resistance. We previously reported that IGF‐I signaling confers resistance to the growth‐inhibitory actions of trastuzumab in a model system, but the underlying molecular mechanism remains unknown. We used SKBR3/neo cells (expressing few IGF‐I receptors) and SKBR3/IGF‐IR cells (overexpressing IGF‐I receptor) as our experimental model. IGF‐I antagonized the trastuzumab‐induced increase in the level of the Cdk inhibitor p27Kip1. This resulted in decreased association of p27Kip1 with Cdk2, restoration of Cdk2 activity and attenuation of cell‐cycle arrest in G1 phase, all of which had been induced by trastuzumab treatment in SKBR3/IGF‐IR cells. We also found that the decrease in p27Kip1 induced by IGF‐I was accompanied by an increase in expression of Skp2, which is a ubiquitin ligase for p27Kip1, and by increased Skp2 association with p27Kip1. A specific proteasome inhibitor (LLnL) completely blocked the ability of IGF‐I to reduce the p27Kip1 protein level, while IGF‐I increased p27Kip1 ubiquitination. This suggests that the action of IGF‐I in conferring resistance to trastuzumab involves targeting of p27Kip1 to the ubiquitin/proteasome degradation machinery. Finally, specific inhibitors of MAPK and PI3K suggest that the IGF‐I‐mediated reduction in p27Kip1 protein level by increased degradation predominantly involves the PI3K pathway. Our results provide an example of resistance to an antineoplastic therapy that targets one tyrosine kinase receptor by increased signal transduction through an alternative pathway in a complex regulatory network. © 2003 Wiley‐Liss, Inc.
Role of 24‐hydroxylase in vitamin D3 growth response of OVCAR‐3 ovarian cancer cells
Authors: Miettinen Susanna , Ahonen Merja H. , Lou Yan‐Ru , Manninen Tommi , Tuohimaa Pentti , Syvälä Heimo , Ylikomi Timo
Published: November 2003

Vitamin D and its analogues are potent regulators of cell growth and differentiation both in vivo and in vitro. We studied the effects of 25‐hydroxyvitamin D3 [25(OH)D3], 1,25‐dihydroxyvitamin D3 [1,25(OH)2D3] and vitamin D analogue, EB 1089, on the growth of a human ovarian cancer cell line, OVCAR‐3. We also studied the expression of vitamin D metabolising enzymes 24‐hydroxylase (24OHase) and 1α‐hydroxylase (1αOHase). Our results showed that high concentrations (10 and 100 nM) of 1,25(OH)2D3 inhibited a cell proliferation, whereas low concentration (0.1 nM) stimulated growth of the OVCAR‐3 cells. In the concentration range of 10–500 nM a prohormone, 25(OH)D3, stimulated growth. An amount of 1 nM EB 1089 and 100 nM 1,25(OH)2D3 inhibited growth with an equal magnitude. The expression of 24OHase was strongly induced by 1,25(OH)2D3 and EB 1089 in OVCAR‐3 cells, and analysis of vitamin D metabolites showed the functionality of 24OHase. An inhibition of 24OHase activity with a novel 24OHase inhibitor enhanced growth‐inhibiting effects of 1,25(OH)2D3 and suppressed the growth stimulation of 100 nM 25(OH)D3. We also report the expression of a vitamin D activating enzyme, 1αOHase, in 7 ovarian cancer cell lines. The production of 1,25(OH)2D3 in OVCAR‐3 cells was low, possibly due to an extensive activity of 24OHase or a low 1αOHase activity. These results suggest that in ovarian cancer cells vitamin D metabolizing enzymes might play a key role in modulating the growth response to vitamin D. The possible mitogenic effects of vitamin D should be considered when evaluating treatment of ovarian cancer with vitamin D. © 2003 Wiley‐Liss, Inc.
Polyglutamine repeat length in the AIB1 gene modifies breast cancer susceptibility in BRCA1 carriers
Authors: Kadouri Luna , Kote‐Jarai Zsofia , Easton Douglas F. , Hubert Ayala , Hamoudi Rifat , Glaser Benjamin , Abeliovich Dvorah , Peretz Tamar , Eeles Rosalind A.
Published: November 2003

Variation in the penetrance estimates for BRCA1 and BRCA2 mutation carriers suggests that other factors may modify cancer risk from specific mutations. One possible mechanism is an epigenetic effect of polymorphisms in other genes. Genes involved in hormonal signal transduction are possible candidates. The AIB1 gene, an estrogen receptor (ER) coactivator, is frequently amplified in breast and ovarian tumors. Variation of a CAG repeat length has been reported within this gene that encodes a polyglutamine repeat in the C‐terminus of the protein. Three hundred eleven BRCA1/2 mutation carriers (257 were of Ashkenazi origin) were genotyped for the AIB1 polyglutamine repeat. Relative risks (RR) were estimated using a maximum likelihood approach. The estimated breast cancer (BC) RR per average repeat length adjusted for population type (Ashkenazi vs. non‐Ashkenazi) was 1.15 (95% CI = 1.02–1.30; p = 0.01) for BRCA1/2 carriers, and 1.25 (95% CI = 1.09–1.42; p = 0.001) when analysis was restricted to BRCA1 carriers. RR of BC was 1.17 (95% CI = 0.91–1.74), for individuals with 2 alleles ≥29 polyglutamine repeats and 0.78 (95% CI = 0.50–1.16) for those with at least 1 allele of ≤26 repeats, compared to individuals with the common genotypes 28;28, 28;29 or 28;30. The corresponding BC RR in BRCA1 mutation carriers was 0.55 (95% CI = 0.34–0.90) and 1.29 (95% CI = 0.85–1.96) in those with ≤26 and ≥29 repeats respectively (p = 0.025). These results indicate significant association of the risk for BC in carriers of BRCA1 mutations with the polyglutamine chain of the AIB1 gene. Longer repeat length correlates with elevated risk, whereas in carriers of a shorter AIB1 allele BC risk was reduced. The AIB1 polyglutamine length did not affect BC risk among BRCA2 mutation carriers. © 2003 Wiley‐Liss, Inc.
Comparison of risk factors for colon and rectal cancer
Authors: Wei Esther K. , Giovannucci Edward , Wu Kana , Rosner Bernard , Fuchs Charles S. , Willett Walter C. , Colditz Graham A.
Published: November 2003

Predictors of colorectal cancer have been extensively studied with some evidence suggesting that risk factors vary by subsite. Using data from 2 prospective cohort studies, we examined established risk factors to determine whether they were differentially associated with colon and rectal cancer. Our study population included 87,733 women from the Nurses' Health Study (NHS) and 46,632 men from the Health Professionals Follow Up Study (HPFS). Exposure information was collected via biennial questionnaires (dietary variables were collected every 4 years). During the follow‐up period (NHS: 1980 to May 31, 2000; HPFS: 1986 to January 31, 2000), we identified 1,139 cases of colon cancer and 339 cases of rectal cancer. We used pooled logistic regression to estimate multivariate relative risks for the 2 outcomes separately and then used polytomous logistic regression to compare these estimates. In the combined cohort, age, gender, family history of colon or rectal cancer, height, body mass index, physical activity, folate, intake of beef, pork or lamb as a main dish, intake of processed meat and alcohol were significantly associated with colon cancer risk. However, only age and sex were associated with rectal cancer. In a stepwise polytomous logistic regression procedure, family history and physical activity were associated with statistically significant different relative risks of colon and rectal cancer. Our findings support previous suggestions that family history and physical activity are not strong contributors to the etiology of rectal cancer. Future investigations of colon or rectal cancer should take into consideration risk factor differences by subsite. © 2003 Wiley‐Liss, Inc.
A dual‐level ab initio and hybrid density functional theory dynamics study on the unimolecular decomposition reaction C2H5O → CH2O + CH3
Authors: Zhang Yue , Zhang Shaowen , Li Qian Shu
Published: November 2003

We present a direct ab initio and hybrid density functional theory dynamics study of the thermal rate constants of the unimolecular decomposition reaction of C2H5O → CH2O + CH3 at a high‐pressure limit. MPW1K/6‐31+G(d,p), MP2/6‐31+G(d,p), and MP2(full)/6‐31G(d) methods were employed to optimize the geometries of all stationary points and to calculate the minimum energy path (MEP). The energies of all the stationary points were refined at a series of multicoefficient and multilevel methods. Among all methods, the QCISD(T)/aug‐cc‐pVTZ energies are in good agreement with the available experimental data. The rate constants were evaluated based on the energetics from the QCISD(T)/aug‐cc‐pVTZ//MPW1K/6‐31+G(d,p) level of theory using both microcanonical variational transition state theory (μVT) and RRKM theory with the Eckart tunneling correction in the temperature range of 300–2500 K. The calculated rate constants at the QCISD(T)/aug‐cc‐pVTZ/MPW1K/6‐31+G(d,p) level of theory are in good consistent with experimental data. The fitted three‐parameter Arrhenius expression from the μVT/Eckart rate constants in the temperature range 200–2500 K is k = 2.52 × 1012T0.41e(−8894.0/T) s−1. The falloff curves of pressure‐dependent rate constants are performed using master‐equation method within the temperature range of 391–471 K. The calculated results are in good agreement with the available experimental data. © 2004 Wiley Periodicals, Inc. J Comput Chem 2: 218–226, 2003
Converging free energy estimates: MM‐PB(GB)SA studies on the protein–protein complex Ras–Raf
Authors: Gohlke Holger , Case David A.
Published: November 2003

Estimating protein–protein interaction energies is a very challenging task for current simulation protocols. Here, absolute binding free energies are reported for the complex H‐Ras/C‐Raf1 using the MM‐PB(GB)SA approach, testing the internal consistency and model dependence of the results. Averaging gas‐phase energies (MM), solvation free energies as determined by Generalized Born models (GB/SA), and entropic contributions calculated by normal mode analysis for snapshots obtained from 10 ns explicit‐solvent molecular dynamics in general results in an overestimation of the binding affinity when a solvent‐accessible surface area‐dependent model is used to estimate the nonpolar solvation contribution. Applying the sum of a cavity solvation free energy and explicitly modeled solute–solvent van der Waals interaction energies instead provides less negative estimates for the nonpolar solvation contribution. When the polar contribution to the solvation free energy is determined by solving the Poisson–Boltzmann equation (PB) instead, the calculated binding affinity strongly depends on the atomic radii set chosen. For three GB models investigated, different absolute deviations from PB energies were found for the unbound proteins and the complex. As an alternative to normal‐mode calculations, quasiharmonic analyses have been performed to estimate entropic contributions due to changes of solute flexibility upon binding. However, such entropy estimates do not converge after 10 ns of simulation time, indicating that sampling issues may limit the applicability of this approach. Finally, binding free energies estimated from snapshots of the unbound proteins extracted from the complex trajectory result in an underestimate of binding affinity. This points to the need to exercise caution in applying the computationally cheaper “one‐trajectory‐alternative” to systems where there may be significant changes in flexibility and structure due to binding. The best estimate for the binding free energy of Ras–Raf obtained in this study of −8.3 kcal mol−1 is in good agreement with the experimental result of −9.6 kcal mol−1, however, further probing the transferability of the applied protocol that led to this result is necessary. © 2003 Wiley Periodicals, Inc. J Comput Chem 2: 238–250, 2003
Real‐time imaging of skeletal muscle velocity
Authors: Asakawa Deanna S. , Nayak Krishna S. , Blemker Silvia S. , Delp Scott L. , Pauly John M. , Nishimura Dwight G. , Gold Garry E.
Published: November 2003

Purpose

To test the feasibility of using real‐time phase contrast (PC) magnetic resonance imaging (MRI) to track velocities (1–20 cm/second) of skeletal muscle motion.

Materials and Methods

To do this we modified a fast real‐time spiral PC pulse sequence to accommodate through‐plane velocity encoding in the range of −20 to +20 cm/second. We successfully imaged motion of the biceps brachii and triceps brachii muscles during elbow flexion and extension in seven unimpaired adult subjects using real‐time PC MRI.

Results

The velocity data demonstrate that the biceps brachii and the triceps brachii, antagonistic muscles, move in opposite directions during elbow flexion and extension with velocity values in the muscle tissue ranging from –10 to +10 cm/second.

Conclusion

With further development, real‐time PC MRI may provide a means to analyze muscle function in individuals with neurologic or movement disorders who cannot actively complete the repeated motions required for dynamic MRI techniques, such as cine PC MRI, that are more commonly used in musculoskeletal biomechanics applications. J. Magn. Reson. Imaging 2003;18:734–739. © 2003 Wiley‐Liss, Inc.
Bioresorbable Hydrogels Prepared Through Stereocomplexation between Poly(L‐lactide) and Poly(D‐lactide) Blocks Attached to Poly(ethylene glycol)
Authors: Li Suming
Published: November 2003

Block copolymers were synthesized by ring‐opening polymerization of L‐lactide or D‐lactide in the presence of mono‐ or dihydroxyl poly(ethylene glycol), using zinc metal as catalyst. The resulting copolymers were characterized by various techniques, namely 1H NMR spectroscopy, differential scanning calorimetry (DSC), X‐ray diffractometry, and Raman spectrometry. The composition of the copolymers was designed such that they were water soluble. Bioresorbable hydrogels were prepared from aqueous solutions containing both poly(L‐lactide)/poly(ethylene glycol) and poly(D‐lactide)/poly(ethylene glycol) block copolymers. Rheological studies confirmed the formation of hydrogels resulting from stereocomplexation between poly(L‐lactide) and poly(D‐lactide) blocks.

Ring‐opening polymerization of L(D)‐lactide in the presence of dihydroxyl PEG using zinc powder as catalyst.

magnified image

Ring‐opening polymerization of L(D)‐lactide in the presence of dihydroxyl PEG using zinc powder as catalyst.
Functional polymeric materials: complexing amphiphiles as structure‐inducing elements
Authors: ten Brinke Gerrit , Ikkala Olli
Published: November 2003

Self‐assembly of polymeric comb‐shaped supramolecules is a powerful tool to prepare functional materials. Enhanced conductivity due to hexagonal self‐organization of conducting polyaniline and polarized photoluminance in solid‐state films of rodlike poly(2,5‐pyridinediyl) obtained by removing hydrogen‐bonded side chains from the aligned thermotropic smectic phase are two examples. Hierarchically structured materials are formed when the self‐organization of block copolymers is combined with that of comb‐shaped supramolecules. These form the basis for tunable nanoporous membranes, nano‐objects and materials with anisotropic properties such as tridirectional proton conductivity.
On the clathrate structures of syndiotactic poly(m‐methylstyrene)
Authors: Tarallo Oreste , Buono Annamaria , Califano Valeria , Petraccone Vittorio
Published: November 2003

The crystal structures of clathrate forms of syndiotactic poly(m‐methylstyrene) containing guest molecules having different steric hindrance (CS2, benzene and orto‐dichlorobenzene) are presented. The structures are all characterized by polymer chains in s(2/1)2 helical conformation and guest molecules packed in an orthorhombic unit cell according to the space group Pcaa. All the presented clathrates belongs to β class indipendently from the dimensions of the guest molecule. In this aspect they differ both from clathrate forms of syndiotactic polystyrene, all belonging to α class, and from clathrate forms of syndiotactic poly(p‐methylstyrene) that belong to α or β class according to the steric hindrance of the guest molecule.
Rationalizing the meaning of coefficients in Flory‐Huggins approach to polymer‐solvent interactions
Authors: Lucchelli Emilio , Caccianotti Luciano
Published: November 2003

The Flory‐Huggins interaction parameter for a polymer solution can be represented as the product of two functions, which separately take into account the effects of the polymer volume fraction and temperature. The latter factor contains three constants, usually viewed as best‐fit coefficients. They are expressed in terms of two thermodynamic quantities, namely, the excess partial molar heat capacity of the solution and a reference temperature, thus allowing to guess their physical meaning. The formulae so obtained were tested with satisfactory results for two solutions of polystyrene in acetone and for two polymer blends (PC/PMMA and PS/PVME.) Furthermore, an attempt was made to calculate the above‐mentioned reference temperature from data referring to the phases in solution.
Starch swelling and its role in modern ceramic shaping technology
Authors: Týnová Eva , Pabst Willi , Mikač Jan
Published: November 2003

A microscopic real‐time visualisation of potato starch swelling in aqueous media at 56°C is performed. The viscosity increase of a starch‐water mixture during the swelling step is documented by viscometric measurements. The mechanism of ceramic green‐body formation in a new ceramic shaping process, called “starch consolidation”, is discussed. In particular, the rheological changes during swelling and their concomitant structural background can explain certain discrepancies between model predictions and experimental findings observed in previous work.
Dynamic properties of protein‐like heteropolymers: a computer simulation study
Authors: Romiszowski Piotr , Sikorski Andrzej
Published: November 2003

A simple model of a single polypeptide chain was used in the computer simulation. The units in a model polypeptide were located at α‐carbons and embedded in a very flexible [310] lattice. The force field that mimics polymer‐polymer and polymer‐solvent interactions contained a long‐range contact potential between the residues as well as local preferences in forming helical structures. The chain consisted of two types of residues: hydrophilic and hydrophobic. The classic Metropolis simulation algorithm was used. Monte Carlo simulations were carried out for helical sequences of residues and for various temperature conditions. It was shown that the formation of secondary structures in the chain under consideration had an influence on local short‐time dynamic properties. The analysis of the autocorrelation functions enables one to identify the presence of secondary structures. The analysis of the formation of polymer‐polymer and polymer‐solvent contacts in ordered structures was also made.
Conductive polymer composites (CPC): influence of processing conditions, shear rate and temperature on electrical properties of poly(butylene terephthalate)/poly(amide12‐b‐tetramethyleneglycol) – carbon black blends
Authors: Feller Jean‐François , Petitjean Énora
Published: November 2003

Conductive Polymer Composites (CPC) have been obtained by blending two immiscible polymers, poly(butylene terephthalate) (PBT) and poly(amide12‐b‐tetramethyleneglycol) (PEBAX) with carbon black (CB). The extrusion process allows to obtain anisotrope co‐continuous structures of various morphologies depending on composition and experimental conditions. It is possible to enhance CPC conductivity with appropriate processing temperature (Tp) and screw speed (Ω), without changing the composition of the blend. The best results are obtained with Ω =5 rpm and Tp=260°C. PBT/PEBAX‐CB resistivity evolution with Tp and Ω doesn't follow a linear law as expected from previous studies with poly(butylene terephthalate)/poly(ethylene)‐CB and poly(butylene terephthalate)/poly(ethylene‐co‐ethyl acrylate)‐CB systems. CB distribution has a more important impact on conductivity than polymers phase morphology. A good control of these parameters is essential to reproduce and optimize electrical properties.
Automated assessment of cervical dystonia
Authors: Galardi Giuseppe , Micera Silvestro , Carpaneto Jacopo , Scolari Silvana , Gambini Massimo , Dario Paolo
Published: November 2003

We developed an automated and objective method to measure posture and voluntary movements in patients with cervical dystonia using Fastrack, an electromagnetic system consisting of a stationary transmitter station and four sensors. The junction lines between the sensors attached to the head produced geometrical figures on which the corresponding aspects of the head were superimposed. The head position in the space was reconstructed and observed from axial, sagittal, and coronal planes. Four patients with cervical dystonia and 6 healthy subjects were studied. Each patient was representative of one of the typical patterns of cervical dystonia. The study allowed the authors to collect quantitative data on posture and range of motion of the head. This pilot study demonstrates the efficacy of the Fastrack system to objectively measure the head position in cervical dystonia patients. © 2003 Movement Disorder Society
Numerical finite element formulation of the Schapery non‐linear viscoelastic material model
Authors: Haj‐Ali Rami M. , Muliana Anastasia H.
Published: November 2003

This study presents a numerical integration method for the non‐linear viscoelastic behaviour of isotropic materials and structures. The Schapery's three‐dimensional (3D) non‐linear viscoelastic material model is integrated within a displacement‐based finite element (FE) environment. The deviatoric and volumetric responses are decoupled and the strain vector is decomposed into instantaneous and hereditary parts. The hereditary strains are updated at the end of each time increment using a recursive formulation. The constitutive equations are expressed in an incremental form for each time step, assuming a constant incremental strain rate. A new iterative procedure with predictor–corrector type steps is combined with the recursive integration method. A general polynomial form for the parameters of the non‐linear Schapery model is proposed. The consistent algorithmic tangent stiffness matrix is realized and used to enhance convergence and help achieve a correct convergent state. Verifications of the proposed numerical formulation are performed and compared with a previous work using experimental data for a glassy amorphous polymer PMMA. Copyright © 2003 John Wiley & Sons, Ltd.
An enriched meshless method for non‐linear fracture mechanics
Authors: Rao B. N. , Rahman S.
Published: November 2003

This paper presents an enriched meshless method for fracture analysis of cracks in homogeneous, isotropic, non‐linear‐elastic, two‐dimensional solids, subject to mode‐I loading conditions. The method involves an element‐free Galerkin formulation and two new enriched basis functions (Types I and II) to capture the Hutchinson–Rice–Rosengren singularity field in non‐linear fracture mechanics. The Type I enriched basis function can be viewed as a generalized enriched basis function, which degenerates to the linear‐elastic basis function when the material hardening exponent is unity. The Type II enriched basis function entails further improvements of the Type I basis function by adding trigonometric functions. Four numerical examples are presented to illustrate the proposed method. The boundary layer analysis indicates that the crack‐tip field predicted by using the proposed basis functions matches with the theoretical solution very well in the whole region considered, whether for the near‐tip asymptotic field or for the far‐tip elastic field. Numerical analyses of standard fracture specimens by the proposed meshless method also yield accurate estimates of the J‐integral for the applied load intensities and material properties considered. Also, the crack‐mouth opening displacement evaluated by the proposed meshless method is in good agreement with finite element results. Furthermore, the meshless results show excellent agreement with the experimental measurements, indicating that the new basis functions are also capable of capturing elastic–plastic deformations at a stress concentration effectively. Copyright © 2003 John Wiley & Sons, Ltd.
Interface current method for multi‐region neutron diffusion problems
Authors: Atalay M. A. , Aydin M.
Published: November 2003

This paper presents an interface current method for solving multi‐region neutron diffusion problems using multi‐dimensional Green's functions. The method is based on evaluation of the net currents at each interface. The unknown interface currents are expanded in terms of eigenfunctions. The orthogonality condition of the eigenfunctions is employed in order to transform these equations to an algebraic system. Numerical examples are provided at the end of the paper to demonstrate the validity of the method, and for comparison with the more established finite difference method. Copyright © 2003 John Wiley & Sons, Ltd.
Multiscale Galerkin method using interpolation wavelets for two‐dimensional elliptic problems in general domains
Authors: Jang Gang‐Won , Kim Jae Eun , Kim Yoon Young
Published: November 2003

One major hurdle in developing an efficient wavelet‐based numerical method is the difficulty in the treatment of general boundaries bounding two‐ or three‐dimensional domains. The objective of this investigation is to develop an adaptive multiscale wavelet‐based numerical method which can handle general boundary conditions along curved boundaries. The multiscale analysis is achieved in a multi‐resolution setting by employing hat interpolation wavelets in the frame of a fictitious domain method. No penalty term or the Lagrange multiplier need to be used in the present formulation. The validity of the proposed method and the effectiveness of the multiscale adaptive scheme are demonstrated by numerical examples dealing with the Dirichlet and Neumann boundary‐value problems in quadrilateral and quarter circular domains. Copyright © 2003 John Wiley & Sons, Ltd.
Incremental harmonic balance method with multiple time variables for dynamical systems with cubic non‐linearities
Authors: Pušenjak R. R. , Oblak M. M.
Published: November 2003

The incremental harmonic balance method with multiple time variables is developed for analysis of almost periodic oscillations in multi‐degree‐of‐freedom dynamical systems with cubic non‐linearities, subjected to the external multi‐tone excitation. The method is formulated to treat non‐autonomous as well as autonomous dynamical systems. The almost periodic oscillations, which coexist with periodic oscillations in a rotating system model with cubic restoring force and an electromagnetic eddy‐current damper are analysed. The closed form solutions based on generalized Fourier series containing two incommensurate frequencies are obtained in the case of small non‐dimensional stiffness ratio. Almost periodic oscillations of a rotating system model in dependence on variable parameters are also analysed, where solutions are computed through an augmentation process including a greater number of harmonics and combination frequencies involved. Copyright © 2003 John Wiley & Sons, Ltd.
Charts of fetal size: kidney and renal pelvis measurements
Authors: Chitty Lyn S. , Altman Douglas G.
Published: November 2003

Objective

To construct new size charts for fetal kidney measurements and to define normal limits for renal pelvic antero‐posterior diameter.

Methods

A prospective, cross‐sectional study was carried out in the ultrasound department of a large hospital. Six hundred and sixty‐three fetuses were scanned only once for the purpose of the study at gestations between 14 and 42 weeks. Centiles for kidney dimensions were estimated by combining separate fractional polynomial regression models fitted to the mean and standard deviation, assuming that the measurements have a normal distribution at each gestational age. Centiles for renal pelvic diameter were obtained using quantile regression.

Results

Size charts for fetal kidney dimensions [antero‐posterior (AP), transverse, length and volume] and renal pelvis diameter are presented and compared with previously published data.

Conclusion

We present new size charts for fetal kidney size that take into consideration the increasing variability with gestational age. These data should aid the prenatal diagnosis of renal pathology by defining renal size and the upper limits of normal pelvic dilatation. They may be particularly useful in the third trimester where there is limited data available. Our data confirm that it is reasonable to use an upper limit of 7 mm for the AP diameter in late pregnancy. Copyright © 2003 John Wiley & Sons, Ltd.
Meconium peritonitis and pseudo‐cyst formation: prenatal diagnosis and post‐natal course
Authors: Eckoldt F. , Heling K. S. , Woderich R. , Kraft S. , Bollmann R. , Mau H.
Published: November 2003

Objectives

Intra‐uterine bowel perforation can occur secondary to a variety of abnormalities and cause sterile peritonitis in the fetus (generalised = type I). If sealing of the perforation does not take place, a thick‐walled pseudo‐cyst can form (type II).

Methods

Over a 12‐year period, 21 616 pregnancies were screened for gastro‐intestinal malformations using prenatal ultrasound. We identified 1077 cases suspicious of surgically correctable malformations. Post‐natal diagnoses and outcome were worked up retrospectively.

Result

We found 96 fetuses with suspected gastro‐intestinal malformations. Prenatal bowel perforation with meconium peritonitis was confirmed in 11 cases. In 5 of these 11, the correct diagnosis had been predicted prenatally. One child presented as a fetal and neonatal emergency (case report). Ten of the eleven infants were operated on during their first day of life. Intra‐operative findings were atresia (n = 4), meconium ileus (n = 6) and no obvious cause (n = 1). Two children suffered fatal complications.

Conclusion

Meconium peritonitis and meconium pseudo‐cysts as its special manifestation are assessable by prenatal diagnosis but present in different ways. They can present as fetal ascites or echogenic bowel and cause fetal or neonatal distress, requiring close observation and highly specialised care. Copyright © 2003 John Wiley & Sons, Ltd.
Detection of an aneurysm of the vein of Galen following signs of cardiac overload in a 22‐week old fetus
Authors: Hartung J. , Heling K. S. , Rake A. , Zimmer C. , Chaoui R.
Published: November 2003

Objectives

To present early prenatal diagnosis of an aneurysm of the Vein of Galen by detecting signs of cardiac overload in a 22‐week old fetus.

Case

We report on a 22‐week old fetus presenting with dilation of the heart, tricuspid and mitral valve regurgitation, reversed flow in the aortic arch and dilated neck vessels. Evaluation of the fetal brain revealed a dilated left ventricle, signs of brain hemorrhage and an anechoic structure between the two hemispheres.

Methods

By using the conventional Doppler technique, an intracerebral fistula and dilated vein of Galen was visualized. The complex vascular structure was demonstrated using 3‐D color power angiography (3‐D CPA). To our knowledge, this is the earliest diagnosis of this vascular malformation.

Conclusion

Although signs of cardiac overload rarely appear before the third trimester in cases of arteriovenous fistulae, it was shown that these signs could lead to the correct diagnosis of an aneurysm of the vein of Galen. Additionally, we show that 3‐D CPA is a promising technique to visualize complex vascular structures and make them easier to understand. Copyright © 2003 John Wiley & Sons, Ltd.
Sliding mode control of boost and buck‐boost power converters using the dynamic sliding manifold
Authors: Shtessel Yuri B. , Zinober Alan S. I. , Shkolnikov Ilia A.
Published: November 2003

Non‐minimum phase tracking control is studied for boost and buck‐boost power converters. A sliding mode control algorithm is developed to track directly a causal voltage tracking profile given by an exogenous system. The approximate causal output non‐minimum phase asymptotic tracking in non‐linear boost and buck‐boost power converters is addressed via sliding mode control using a dynamic sliding manifold (DSM). Use of DSM allows the stabilization of the internal dynamics when the output tracking error tends asymptotically to zero in the sliding mode. The sliding mode controller with DSM links features of conventional sliding mode control (insensitivity to matched non‐linearities and disturbances) and a conventional dynamic compensator (accommodation to unmatched disturbances). Numerical examples demonstrate the effectiveness of the sliding mode controller even for a known time‐varying load. Copyright © 2003 John Wiley & Sons, Ltd.
A nonlinear set‐membership filter for on‐line applications
Authors: Scholte Eelco , Campbell Mark E.
Published: November 2003

A guaranteed estimator for a general class of nonlinear systems and on‐line usage is developed and analysed. This filter bounds the linearization error, then applies a linear set‐membership filter such that stability guarantees hold for nonlinear systems. A tight bound on the linearization error is found using interval analysis. This filter recursively estimates an ellipsoidal set in which the true state lies. General assumptions include the use of bounded noises and twice continuously differentiable dynamics. When the system is uniformly observable, it is proven that the nonlinear set‐membership filter is stable. In addition, if no noise is present and the initial error is small, the error between the centre of the estimated set and the true value converges to zero. The result is an estimator which is computationally attractive and can be implemented robustly in real‐time. The proposed method is applied to a two‐state example to demonstrate the theoretical results. Copyright © 2003 John Wiley & Sons, Ltd.
Gastrectomy, peritonectomy, and perioperative intraperitoneal chemotherapy: The evolution of treatment strategies for advanced gastric cancer
Authors: Sugarbaker Paul H. , Yu Wansik , Yonemura Yutaka
Published: November 2003

Gastric cancer disseminates by hematogenous, lymphatic, and transcoelomic routes. For maximal containment of the malignant process, perioperative intraperitoneal chemotherapy is necessary in two groups of patients in whom the primary cancer can be resected. Those patients who have been resected for cure and have a high likelihood of microscopic residual disease require intraperitoneal chemotherapy. This includes all T3 and T4 patients, and patients with N2 nodes present. A series of randomized and nonrandomized clinical studies have established the benefits of perioperative intraperitoneal chemotherapy in this group of patients. Patients with stage IV disease who are able to undergo a palliative resection require these treatments if peritoneal seeding is observed. Systemic chemotherapy is largely ineffective for peritoneal seeding, while intraperitoneal chemotherapy is most likely to produce a response with small volume, surgically debulked carcinomatosis. In addition, intraperitoneal chemotherapy can eliminate the future development of debilitating ascites. Sufficient data are available from the gastric cancer literature to support the use of these combined treatments on a routine basis if the primary cancer is resectable and gastrointestinal function can be reestablished. Semin. Surg. Oncol. 21:233–248, 2003. © 2003 Wiley‐Liss, Inc.
Preoperative chemoradiation for locally advanced rectal cancer: rationale, technique, and results of treatment
Authors: Crane Christopher H. , Skibber John
Published: November 2003

Over the past decade, 392 patients with stage II and III rectal cancer have been managed with preoperative chemoradiation and surgery at the M. D. Anderson Cancer Center (MDACC). Aggressive surgical techniques such as total mesorectal excision, proctectomy with coloanal anastamosis, and multivisceral excisions have been used. Initial pelvic chemoradiation is also used in patients who present with metastases. Preoperative chemoradiation followed by surgery has resulted in excellent sphincter preservation (SP) and pelvic control with minimal acute, perioperative, and late morbidity. SP has been achieved in greater numbers of patients over the past 3 years due to the increased use of coloanal anastamosis in very low tumors. There has been no increase in pelvic failure or perioperative morbidity with this practice. Patients with clinical T4 disease have significantly worse pelvic control. An assessment of the impact of CB on pelvic control and survival requires further follow‐up. Poor differentiation and poor response to preoperative therapy predict a worse overall survival. Durable symptom control without colostomy has been achieved using initial chemoradiation in patients who present with metastases. Aggressive bowel management and skin care can minimize hospitalization and treatment interruption due to acute toxicity. Multidisciplinary therapy using preoperative chemoradiation and aggressive surgery has resulted in excellent SP and pelvic control. However, more effective systemic therapies are needed, especially for patients who do not respond well to preoperative chemoradiation. Semin. Surg. Oncol. 21:265–270, 2003. © 2003 Wiley‐Liss, Inc.
The effects of an integrative supply chain strategy on customer service and financial performance: an analysis of direct versus indirect relationships
Authors: Vickery Shawnee K , Jayaram Jayanth , Droge Cornelia , Calantone Roger
Published: November 2003

This study examines the performance implications of an integrated supply chain strategy, with customer service performance followed by financial performance as performance constructs. Two major components of an integrated supply chain strategy are identified and defined: (1) integrative information technologies, which is modeled antecedent to (2) supply chain integration. The research model was tested using data from a sample (n=57) of the top 150 independent first tier automotive suppliers to the Big 3 in North America. The results showed positive direct relationships between (1) integrated information technologies and supply chain integration, (2) supply chain integration and customer service, and (3) customer service and firm performance. The relationship of supply chain integration to financial performance was indirect, through customer service; i.e., customer service was found to fully (as opposed to partially) mediate the relationship between supply chain integration and firm performance for first tier suppliers in the automotive industry.
The survivorship bias, share price effect, and small firm effect in Canadian markets
Authors: Elfakhani Said , Wei Jason
Published: November 2003

After controlling for survivorship bias, we examine the relation between average returns, firm size, and price levels for Canadian stocks during the 1975–1994 period. Our findings indicate that there is a significant inverse share price level effect in Canadian markets. When we compare the results of the overall sample with the groups of surviving firms and delisted stocks, the latter group shows strong performance for large‐size, high‐priced stocks. Evidence that supports an independent size effect is less clear for Canadian stocks. A small size effect exists only among the higher share price denominations, which suggests a confounded size‐price effect. Although the delisted group returns are statistically different from those of the survivor and the overall groups, which implies some evidence of survivorship bias, the difference between the survivor group and the overall group is weak at best.
The mitochondrial genome of the thermal dimorphic fungus Penicillium marneffei is more closely related to those of molds than yeasts
Authors: Woo Patrick C.Y. , Zhen Hongjun , Cai James J. , Yu Jun , Lau Susanna K.P. , Wang Jian , Teng Jade L.L. , Wong Samson S.Y. , Tse Ronald H. , Chen Ran , Yang Huanming , Liu Bin , Yuen Kwok-yung
Published: November 2003

We report the complete sequence of the mitochondrial genome of Penicillium marneffei, the first complete mitochondrial DNA sequence of a thermal dimorphic fungus. This 35 kb mitochondrial genome contains the genes encoding ATP synthase subunits 6, 8, and 9 (atp6, atp8, and atp9), cytochrome oxidase subunits I, II, and III (cox1, cox2, and cox3), apocytochrome b (cob), reduced nicotinamide adenine dinucleotide ubiquinone oxireductase subunits (nad1, nad2, nad3, nad4, nad4L, nad5, and nad6), ribosomal protein of the small ribosomal subunit (rps), 28 tRNAs, and small and large ribosomal RNAs. Analysis of gene contents, gene orders, and gene sequences revealed that the mitochondrial genome of P. marneffei is more closely related to those of molds than yeasts.
Prediction of the structure and function of AstA and AstB, the first two enzymes of the arginine succinyltransferase pathway of arginine catabolism
Authors: Shirai Hiroki , Mizuguchi Kenji
Published: November 2003

Arginine succinyltransferase and succinylarginine dihydrolase catalyze the first two steps of arginine catabolism by the arginine succinyltransferase pathway. This route is the only major arginine catabolic pathway in Escherichia coli including its pathogenic strains O157 and CFT073. We have used fold recognition tools and identified novel homologies between each of these two enzymes and proteins of known three‐dimensional structure: arginine succinyltransferase belongs to the acyl‐CoA N‐acyltransferase superfamily and succinylarginine dihydrolase belongs to the amidinotransferase superfamily. These findings shed light on the structures, catalytic mechanisms and evolution of diverse enzymes involved in arginine catabolism.
Tribal Participatory Research: Mechanisms of a Collaborative Model
Authors: Fisher Philip A. , Ball Thomas J.
Published: November 2003

Although much social science research has been conducted within American Indian and Alaska Native (AIAN) communities, relatively little research has been conducted by or for those communities. We describe an approach that facilitates the active involvement of AIAN communities in the research process, from conceptualizing the issues to be investigated to developing a research design, and from collecting, analyzing, and interpreting the data to disseminating the results. The Tribal Participatory Research (TPR) approach is consistent with recent developments in psychology that emphasize the inclusion of community members and the social construction of knowledge. We describe the foundations of the approach and present specific mechanisms that can be employed in collaborations between researchers and AIAN communities. We conclude with a discussion of the implications of the use of TPR regarding project timelines and budgets, interpretation of the data, and ultimately the relationships between tribes and researchers.
Reconceptualizing Quantitative and Qualitative Methods: A Case Study Dealing with Place as an Exemplar
Authors: Langhout Regina Day
Published: November 2003

A useful framework for understanding methods is to think of them as being on a continuum of holistic and pattern focused to particularistic and specific. This paper argues for this conceptualization rather than thinking of quantitative and qualitative methods as oppositional and potentially contradictory. A case study provides an example of using both quantitative and qualitative methods in a holistic and pattern‐focused study, while also attending to the values and goals of community psychology. The substantive research goal is to understand a child's experience of places related to school. Methods include ethnographic long‐term participation and observation, interviews, multidimensional scaling, and social network analysis. Most quantitative method variables are generated from study participant; no outside structure is imposed. The quantitative methods extend and inform the qualitative methods, just as the qualitative methods extend and inform the quantitative methods. The quantitative and qualitative methods work reciprocally to extend and inform each other.