bluuebunny/crossref_metadata_2025_split huggingface dataset:
Loss of heterozygosity in serial plasma DNA samples during follow‐up of women with breast cancer
Authors: Wang Qiu , Larson Pamela S. , Schlechter Benjamin L. , Zahid Naila , Finnemore Erin , de las Morenas Antonio , Blanchard Rita A. , Rosenberg Carol L. 
Published: August 2003

AbstractWe evaluated the potential utility of occult circulating tumor DNA as a molecular marker of disease in subjects previously diagnosed with breast cancer. Using 24 microsatellite markers located at sites of frequent loss of heterozygosity (LOH) or allele imbalance in breast cancer, we analyzed DNA from 16 primary tumors (Stage IIA or more advanced) and 30 longitudinally collected plasma specimens. Clinical data at the time of plasma collection were obtained. All 16 tumors were characterized by an individual pattern of LOH. LOH was detected in 12 of 30 (40%) plasma samples, taken from 8 of 14 (57%) subjects. However, the number of LOH in plasma was small (n = 15), and the mean proportion of LOH was much lower than in the tumors (0.05 vs. 0.52). Although infrequent, 12 of 15 (80%) plasma LOH were concordant with abnormalities in the paired tumors, and the mean percent LOH was higher than in normal plasmas, suggesting that they were authentic tumor‐derived abnormalities. We found, despite this, no association, between plasma LOH and tumor stage or clinical status at time of blood collection (i.e., LOH was as common in subjects with no evident disease as in those with evident disease). In addition, detection of LOH was not consistent between serial samples from 5 of 11 subjects (45%), despite stable clinical conditions. No association with clinical outcome was evident, although the sample size was small. Microsatellite instability in plasma was infrequent, nonconcordant with paired tumor and inconsistent in serial samples. This pilot study suggests that identifying tumor‐specific LOH in the plasma of breast cancer subjects may not be useful for detecting occult metastases or for monitoring disease. Other detection techniques may be more promising, but circulating tumor DNA may not be a sufficiently accurate reflection of breast cancer clinical status or tumor activity. © 2003 Wiley‐Liss, Inc.
Incentive effects in the demand for health care: a bivariate panel count data estimation
Authors: Riphahn Regina T. , Wambach Achim , Million Andreas 
Published: August 2003

AbstractThis paper contributes in three dimensions to the literature on health care demand. First, it features the first application of a bivariate random effects estimator in a count data setting, to permit the efficient estimation of this type of model with panel data. Second, it provides an innovative test of adverse selection and confirms that high‐risk individuals are more likely to acquire supplemental add‐on insurance. Third, the estimations yield that in accordance with the theory of moral hazard, we observe a much lower frequency of doctor visits among the self‐employed, and among mothers of small children. Copyright © 2002 John Wiley & Sons, Ltd.
Evaluating interval forecasts of high‐frequency financial data
Authors: Clements Michael P. , Taylor Nick 
Published: August 2003

AbstractA number of methods of evaluating the validity of interval forecasts of financial data are analysed, and illustrated using intraday FTSE100 index futures returns. Some existing interval forecast evaluation techniques, such as the Markov chain approach of Christoffersen (1998), are shown to be inappropriate in the presence of periodic heteroscedasticity. Instead, we consider a regression‐based test, and a modified version of Christoffersen's Markov chain test for independence, and analyse their properties when the financial time series exhibit periodic volatility. These approaches lead to different conclusions when interval forecasts of FTSE100 index futures returns generated by various GARCH(1,1) and periodic GARCH(1,1) models are evaluated. Copyright © 2003 John Wiley & Sons, Ltd.
Testing long‐run PPP with infinite‐variance returns
Authors: Falk Barry , Wang Chun‐Hsuan 
Published: August 2003

AbstractThis paper investigates the long‐run purchasing power parity hypothesis when exchange rate returns and inflation rates are assumed to be heavy‐tailed stochastic processes. More specifically, residual‐based and likelihood‐ratio‐based cointegration tests of PPP that explicitly allow for infinite‐variance innovations are applied to monthly data (1973:1–1999:12) for Belgium, Canada, Denmark, France, Germany, Italy, Japan, the Netherlands, Norway, Spain, Sweden, and the United Kingdom. Our test results are marginally less supportive of PPP when the innovations are assumed to be infinite‐variance, α‐stable processes. Copyright © 2003 John Wiley & Sons, Ltd.
Three‐dimensional culture of differentiating marrow stromal osteoblasts in biomimetic poly(propylene fumarate‐co‐ethylene glycol)‐based macroporous hydrogels
Authors: Behravesh Esfandiar , Mikos Antonios G. 
Published: August 2003

AbstractThis study assesses the ability of biomimetic poly(propylene fumarate‐co‐ethylene glycol)‐based hydrogels to sustain the differentiation of marrow stromal cells (MSCs) to the osteoblastic phenotype and to produce a mineralized matrix in vitro. Macroporous hydrogels based on poly(propylene fumarate‐co‐ethylene glycol) with and without covalently linked RGD cell‐adhesive peptide were synthesized and seeded with rat MSCs suspended in media or in a type I collagen solution. Cells suspended in media were found to adhere to RGD‐modified but not to unmodified hydrogels. Cells suspended in a collagen solution were entrapped after collagen gelation and proliferated independent of the peptide modification of the hydrogel. Hydrogel modification with RGD peptide was sufficient to allow for the adhesion and differentiation of MSCs to the osteoblastic phenotype in the presence of osteogenic culture supplements. MSCs seeded with a collagen gel onto RGD‐modified macroporous hydrogels after 28 days of culture showed a significant increase in cell numbers, from 15,200 ± 2,000 to 208,600 ± 69,700 cells (p < 0.05). Moreover, significant calcium deposition was apparent after 28 days of culture in RGD‐modified hydrogels for cells suspended in a collagen gel in comparison to cells suspended in media, 3.47 ± 0.26 compared to 0.82 ± 0.20 mg Ca2+ per scaffold (p < 0.05). Confocal microscopy revealed that MSCs suspended in a collagen gel and cultured on RGD‐modified hydrogels for 28 days were adhered to the surface of the hydrogel while MSCs suspended in a collagen gel and cultured on unmodified hydrogels were located within the pores of and not in direct contact with the hydrogel surface. The results demonstrate that these biomimetic hydrogels facilitate the adhesion and support the differentiation of MSCs to the osteoblastic phenotype in the presence of osteogenic culture media. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 698–706, 2003
Acceleration effect of basic fibroblast growth factor on the regeneration of peripheral nerve through a 15‐mm gap
Authors: Wang Shenguo , Cai Qing , Hou Jianwei , Bei Jianzhong , Zhang Tao , Yang Jian , Wan Yuqing 
Published: August 2003

AbstractIn this study, nerve guides composed of poly(D,L‐lactide) (PDLLA) were fabricated and used in the repair of transected sciatic nerves (15‐mm gaps) of rats. Nerve guides with a two‐ply structure (inner layer dense, outer layer microporous) were prepared by controlling the solvent evaporation rate. Then basic fibroblast growth factor (bFGF) was embedded in the inner layer of the nerve guides. Thus the inner dense layer not only could prevent the ingrowth of fibroblast and avoid the outgrowing nerve cable, but it also could retain the released bFGF in the guide lumen. The outer porous layer allowed vascular ingrowth and the diffusion of essential nutrients into the guide lumen. The data show that by using this nerve guide, the transected 15‐mm sciatic nerve was regenerated successfully within 4 months. The recovery of function of the regenerated nerves was significantly accelerated by bFGF, as indicated by an electrostimulation test and histologic assays. In addition, the bFGF retained its bioactivity during embedding and continuously was released from the matrix, as confirmed by the results of both the dorsal root ganglia (DRG) and the Schwann cell culture in the presence of PDLLA matrix containing bFGF. The released bFGF enhanced the ability of the nerve fibers to sprout from dorsal root ganglia, and it accelerated the proliferation of Schwann cells. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 522–531, 2003
Nanoscalein vivoevaluation of the stiffness ofDrosophila melanogasterintegument during development
Authors: Kohane M. , Daugela A. , Kutomi H. , Charlson L. , Wyrobek A. , Wyrobek J. 
Published: August 2003

AbstractA quasistatic nanoindentation technique, enhanced by scanning probe microscopy, was used to measure cuticle stiffness of liveDrosophila melanogasterduring its larval, pupal, and early adult developmentin vivo. Stiffness was defined as the reduced elastic modulus (Er), which is a material property related to the elastic modulus.Erwas measured at the local contact while indenting the live sample at a constant loading rate using a spherical tip.Erwas derived from the resultant force‐displacement curves. Insect cuticle exhibits viscoelastic behavior. Constant loading rate quasistatic measurements were used so that the effects of viscosity and contact force adhesion introduced systematic measurement effects.Ervalues were as follows: larvae, mean (SE), 0.39 (0.01) MPa; the puparium without evidence of adult structures 15.43 (1.78) MPa; and the adult, measured in the puparium at the completion of metamorphosis, 4.37 (0.31) MPa. Thus, as expected, the puparium and adult cuticle were very much stiffer than larval cuticle. Results also indicated stiffness variation that related to developmental events. This study has shown that this quasistatic nanoindentation–scanning probe microscopy approach is a suitable method for analyzing live biological samples. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 633–642, 2003
Characterization of cellular carriers for use in injectable tissue‐engineering composites
Authors: McGlohorn Jonathan B. , Grimes Larry W. , Webster Shannon S. , Burg Karen J. L. 
Published: August 2003

AbstractInjectable composite tissue‐engineering scaffolds are systems that incorporate individual cell carriers within a gel delivery matrix. This study assessed low‐temperature casting as a possible method to produce synthetic cell‐carrier beads. Porous poly‐L‐lactide beads were manufactured by low‐temperature casting. Two porogens, either glucose or sodium chloride, were incorporated into the beads and subsequently leached. Beads were seeded with primary culture aortic smooth muscle rat cells and were evaluated over a 13‐day period using a series of chemical, biochemical, and histological assays. Results indicate that low‐temperature casting is a viable technique to produce injectable beads on the order of 1.5–2.0 mm. The manufactured beads supported smooth muscle cell attachment and proliferation; where the beads formed with sodium chloride allowed enhanced proliferation. Differences in physical qualities, namely buoyancy and topography, were dependent on porogen selection and may provide a mechanism for bead and composite customization. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 441–449, 2003
A fibrin‐based arterial media equivalent
Authors: Grassl E. D. , Oegema T. R. , Tranquillo R. T. 
Published: August 2003

AbstractWe report here, with respect to collagen production and the mechanical properties of a fibrin‐based media equivalent (ME), on our efforts to optimize the culture conditions of neonatal SMCs entrapped in tubular fibrin gels. We examined several factors, including the concentration of fibrinolysis inhibitor, the cell source and initial number, the addition of TGF‐β and insulin to the culture medium, and the time in culture. We found that varying the concentration of ϵ‐aminocaproic acid (ACA), an inhibitor of fibrinolysis, did not affect the collagen production, but that lower concentrations resulted in a compromised physical integrity of the ME. While use of neonatal SMCs yielded superior results over adult SMCs, a higher initial cell number did not improve results. The addition of 1 ng/mL of TGF‐β to the medium increased the collagen content fourfold and the ultimate tensile strength (UTS) and modulus approximately tenfold after 3 weeks, while the addition of both TGF‐β and insulin improved collagen content sixfold and UTS and modulus almost 20‐fold. Additional TGF‐β (5 ng/mL) did not improve any of the properties measured, but additional time in culture did. Samples incubated for 6 weeks with TGF‐β and insulin contained about seven times the amount of collagen and had a three‐times higher UTS and modulus than did samples incubated for only 3 weeks. When compared to collagen MEs, the fibrin MEs compacted to a greater extent and were both stronger and stiffer when cultured under the same conditions, having after 6 weeks a tensile modulus and ultimate tensile strength similar to those of rat abdominal aorta. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 550–561, 2003
Ion release in stable hip arthroplasties using metal‐on‐metal articulating surfaces: A comparison between short‐ and medium‐term results
Authors: Savarino L. , Granchi D. , Ciapetti G. , Cenni E. , Greco M. , Rotini R. , Veronesi C. A. , Baldini N. , Giunti A. 
Published: August 2003

AbstractThe use of metallic heads articulating with metallic cups could solve the problem of polyethylene (PE) wear in total hip replacement (THR) with metal‐on‐PE bearings. A conspicuous release of metal ions from new models of metal‐on‐metal bearings has been found in the short‐term, but it is yet unclear whether the medium‐term corrosion rate is high or, on the contrary, it becomes negligible, because of the continuous surface finishing. Our purpose was to compare the serum ion values (nanograms per milliliter) in 15 patients with metal‐on‐metal stable prosthesis (Group A), in the short‐term (subgroup A1; mean follow‐up: 24 mo) and medium‐term (subgroup A2; mean follow‐up: 52 mo), in order to determine whether the ion release decreased with time of implant. Chromium (Cr), cobalt (Co), molybdenum (Mo) and aluminum (Al) were analyzed. Twenty‐two presurgical patients were used for comparison (Group B). The reference range was obtained from a population of 27 healthy subjects (Group C). Co and Cr levels in the medium‐term (subgroup A2) were not decreased in comparison with the short‐term values (subgroup A1) and were significantly higher (p < 0.001) than presurgical and reference values. Otherwise, Mo and Al concentrations were not significantly increased in comparison with reference values. In conclusion, despite the apparent advantage of metal‐on‐metal coupling, especially in younger patient populations, there is a major concern about the extent and duration of the relevant “internal” exposure to Cr and Co ions. This exposure should be carefully monitored, in order to clarify the biologic effects of ion dissemination and, consequently, to identify risks concerning long‐term toxicity of metals. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 450–456, 2003
Glucocorticoid‐treated sheep as a model for osteopenic trabecular bone in biomaterials research
Authors: Augat Peter , Schorlemmer Sandra , Gohl Christine , Iwabu Shohei , Ignatius Anita , Claes Lutz 
Published: August 2003

AbstractThe purpose of this study was to determine the alterations in ovine trabecular bone induced by a combination of ovariectomy and steroid treatment. Twenty‐four female skeletally mature Merino sheep were randomly assigned to ovariectomy alone (OVX), ovariectomy combined with glucocorticoid treatment for 6 months (OVX + GC), or no treatment (control). Biopsies of trabecular bone were harvested 6 and 12 months after the beginning of the study from the proximal tibia. The biopsies were scanned for apparent bone mineral density by quantitative computed tomography and were mechanically tested. Three‐dimensional bone reconstructions were obtained by micro‐computed tomography. Trabecular bone from the OVX + GC animals had a markedly reduced apparent bone mineral density (27% less than control), bone volume (34%), and elastic modulus (36%) at 6 months. At 12 months, the reductions in apparent bone mineral density (33%), bone volume (37%), and elastic modulus (62%) appeared to be even more pronounced. Ovariectomy alone did not result in a perceptible reduction in any parameter. The combination of ovariectomy and glucocorticoid treatment in sheep resulted in a successful induction of substantial loss of trabecular bone and thus may serve as a large‐animal model for osteopenic trabecular bone for the development and testing of orthopedic implants and techniques under osteoporotic conditions. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 457–462, 2003
Quadruple systems of the projective special linear group PSL(2,q), q ≡ 1 (mod 4)
Authors: Keranen M. S. , Kreher D. L. , Shiue P. J.‐S. 
Published: August 2003

AbstractWe determine the distribution of quadruple systems among the orbits of 4‐element subsets under the action of PSL(2,q) on the projective line when q ≡ 1 (mod 4). © 2003 Wiley Periodicals, Inc. J Combin Designs 11: 339–351, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jcd.10043
Graph homomorphisms through random walks
Authors: Daneshgar Amir , Hajiabolhassan Hossein 
Published: August 2003

AbstractIn this paper we introduce some general necessary conditions for the existence of graph homomorphisms, which hold in both directed and undirected cases. Our method is a combination of Diaconis and Saloff–Coste comparison technique for Markov chains and a generalization of Haemers interlacing theorem. As some applications, we obtain a necessary condition for the spanning subgraph problem, which also provides a generalization of a theorem of Mohar (1992) as a necessary condition for Hamiltonicity. In particular, in the case that the range is a Cayley graph or an edge‐transitive graph, we obtain theorems with a corollary about the existence of homomorphisms to cycles. This, specially, provides a proof of the fact that the Coxeter graph is a core. Also, we obtain some information about the cores of vertex‐transitive graphs. © 2003 Wiley Periodicals, Inc. J Graph Theory 44: 15–38, 2003
An application of the regularity lemma in generalized Ramsey theory
Authors: Sárközy Gábor N. , Selkow Stanley M. 
Published: August 2003

AbstractGiven graphs G and H, an edge coloring of G is called an (H,q)‐coloring if the edges of every copy of H ⊂ G together receive at least q colors. Let r(G,H,q) denote the minimum number of colors in a (H,q)‐coloring of G. In 9 Erdős and Gyárfás studied r(Kn,Kp,q) if p and q are fixed and n tends to infinity. They determined for every fixed p the smallest q (denoted by qlin) for which r(Kn,Kp,q) is linear in n and the smallest q (denoted by qquad) for which r(Kn,Kp,q) is quadratic in n. They raised the problem of determining the smallest q for which we have $r(K_{n,} K_{p,} q) = \left( {\matrix{n \cr 2 \cr } } \right) - 0(n^2 )$. In this paper by using the Regularity Lemma we show that if $q > q_{quad} + \left\lceil {{{\log _2 p} \over 2}} \right\rceil $, then we have $r(K_{n,} K_{p,} q) = \left( {\matrix{ n \cr 2 \cr } } \right) - 0(n^2 )$. © 2003 Wiley Periodicals, Inc. J Graph Theory 44: 39–49, 2003
Influence of oil‐in‐water emulsion characteristics on initial dynamic flavour release
Authors: Rabe Swen , Krings Ulrich , Berger Ralf G 
Published: August 2003

AbstractProperties of oil‐in‐water (O/W) emulsions affecting initial dynamic flavour release were studied in real time considering mouth conditions. Aroma molecules from different chemical classes at concentrations typically present in beverages were used. The emulsion droplet diameter showed no significant influence on the dynamic flavour release. No barrier properties of the emulsifier were found, as the flavour release from equilibrated emulsions flavoured via either the oil phase or the aqueous phase showed no significant difference. Emulsifier concentrations above the critical micelle concentration did not influence the release. Even though the chemical composition of the lipids had considerable influence on flavour release, phase transition during equilibration from the liquid to the solid state insignificantly affected the initial dynamic release process. Copyright © 2003 Society of Chemical Industry
Chemical composition and physical properties of extruded snacks containing crab‐processing by‐product
Authors: Murphy Michael G , Skonberg Denise I , Camire Mary Ellen , Dougherty Michael P , Bayer Robert C , Briggs Jack L 
Published: August 2003

AbstractThe crab‐processing industries generate millions of pounds of by‐product annually, which results in a loss of edible product and presents a considerable waste disposal problem. The purpose of this research was to investigate the use of crab‐processing by‐product (CB) in the development of a calcium‐rich expanded snack. The specific objectives were to examine the effects of type of CB (wet or dry), feed composition and screw speed (150 or 250 rpm) on selected properties of extruded snacks. Product formulations consisting of 0–400 g kg−1 CB combined with corn meal and potato flakes were processed in a twin‐screw extruder. The resulting extrudates were analysed for proximate and mineral (calcium, sodium) composition, pH, water activity (aw), total plate count, bulk density, expansion ratio and colour. Both CB type and level of incorporation had significant effects (P < 0.05) on the calcium content, expansion ratio, bulk density and pH of the extrudates. Increasing the CB level resulted in increased calcium content (from 5.1 to 52.4 mg g−1) and pH (from 6.1 to 8.8). Screw speed had no significant effects (P > 0.05) on expansion ratio and bulk density. A high processing temperature (157 °C) and low aw resulted in undetectable microbial growth on the extrudates. This research demonstrates that ground crab‐processing by‐product can be successfully incorporated into an expanded snack product. Further research will evaluate consumer response to this novel value‐added product. Copyright © 2003 Society of Chemical Industry
Pectic polysaccharides during ripening of mango (Mangifera indica L)
Authors: Prasanna V , Yashoda HM , Prabha TN , Tharanathan RN 
Published: August 2003

AbstractThe content of pectin decreased from 2.0 to 0.7% fresh weight (FW) and there was a concomitant increase in free galacturonic acid from 36 to 168 mg% FW during ripening of mango. Ion exchange chromatography on DEAE/cellulose resolved the pectic fraction into seven distinct peaks, with all of them showing a drastic decrease in pectin content and molecular weight as fruit ripening progressed, which indicated significant depolymerisation in vivo. Fraction I appeared to be an arabinogalactan‐type polymer, while fractions II and III were heterogalacturonans containing more than 60% galacturonic acid. Hydrolases implicated in pectin depolymerisation were polygalacturonase (PG), pectin methyl esterase (PME), galactanase, arabinanase and β‐galactosidase. They all showed a climacteric peak in activity during ripening, except for PME which showed a continuous decrease in activity after an initial increase. These results are discussed in the light of fruit softening during ripening. Copyright © 2003 Society of Chemical Industry