bluuebunny/crossref_metadata_2025 huggingface dataset:
Trichomonas vaginalis P16 Immunoreactivity in cervicovaginal Pap tests: A diagnostic pitfall
Authors: Pantanowitz Liron , Florence Roxanne R. , Goulart Robert A. , Otis Christopher N.
Published: August 2005

Detection of p16 is emerging as a useful biomarker for Human Papillomavirus (HPV)‐related dysplastic and malignant lesions of the cervix, and as such has potential application to cervicovaginal Papanicolaou (Pap) specimens. While evaluating p16 immunocytochemistry in our laboratory we observed one Pap test in which Trichomonas vaginalis stained positively for p16. We therefore proceeded to determine the frequency of T. vaginalis immunoreactivity for p16 in 10 consecutive, satisfactory, liquid‐based Pap tests diagnosed as negative for intraepithelial lesion or malignancy in which T. vaginalis was present. For each case, a ThinPrep™ slide prepared from residual vial material was immunostained with p16. In an additional case, a prepared cell block was stained with p16. T. vaginalis were consistently p16 positive. We document, for the first time, p16 immunoreactivity of T. vaginalis that, on a Pap slide and cell block, may be morphologically misinterpreted as small dysplastic or malignant epithelial cells. The presence of this parasite in Pap tests may also potentially hinder the use of p16 as an adjunct to liquid‐based cervical screening cytology. Diagn. Cytopathol. 2005;33:210–213. © 2005 Wiley‐Liss, Inc.
Steady filtration problems with seawater intrusion: macro‐hybrid penalized finite element approximations
Authors: Alduncin Gonzalo , Esquivel‐Avila Jorge , Vera‐Guzman Norberto
Published: August 2005

Macro‐hybrid penalized finite element approximations are studied for steady filtration problems with seawater intrusion. On the basis of nonoverlapping domain decompositions with vertical interfaces, sections of coastal aquifers are decomposed into subsystems with simpler geometries and small scales, interconnected via transmission conditions of pressure and flux continuity. Corresponding local penalized formulations are derived from the global penalized variational formulation of the two‐free boundary flow problem, with continuity transmission conditions modelled variationally in a dual sense. Then, macro‐hybrid finite element approximations are derived for the system, defined on independent subdomain grids. Parallel relaxation penalty‐duality algorithms are proposed from fixed‐point problem characterizations. Numerical experiments exemplify the macro‐hybrid penalized theory, showing a good agreement with previous primal conforming penalized finite element approximations (Comput. Methods Appl. Mech. Engng. 2000; 190:609–624). Copyright © 2005 John Wiley & Sons, Ltd.
Evaluation of adaptive mesh refinement and coarsening for the computation of compressible flows on unstructured meshes
Authors: Walter Miguel A. T. , Abdu Aline A. Q. , Figueira da Silva Luís Fernando , Azevedo João Luiz F.
Published: August 2005

The compressible gas flows of interest to aerospace applications often involve situations where shock and expansion waves are present. Decreasing the characteristic dimension of the computational cells in the vicinity of shock waves improves the quality of the computed flows. This reduction in size may be accomplished by the use of mesh adaption procedures. In this paper an analysis is presented of an adaptive mesh scheme developed for an unstructured mesh finite volume upwind computer code. This scheme is tailored to refine or coarsen the computational mesh where gradients of the flow properties are respectively high or low. The refinement and coarsening procedures are applied to the classical gas dynamic problems of the stabilization of shock waves by solid bodies. In particular, situations where oblique shock waves interact with an expansion fan and where bow shocks arise around solid bodies are considered. The effectiveness of the scheme in reducing the computational time, while increasing the solution accuracy, is assessed. It is shown that the refinement procedure alone leads to a number of computational cells which is 20% larger than when alternate passes of refinement and coarsening are used. Accordingly, a reduction of computational time of the same order of magnitude is obtained. Copyright © 2005 John Wiley & Sons, Ltd.
Transforming growth factor‐β‐regulated gene transcription and protein expression in human GFAP‐negative lamina cribrosa cells
Authors: Kirwan Ruaidhrí P. , Leonard Martin O. , Murphy Madeline , Clark Abbot F. , O'Brien Colm J.
Published: August 2005

Primary open‐angle glaucoma (POAG) is a progressive optic neuropathy, which is a major cause of worldwide visual impairment and blindness. Pathological hallmarks of the glaucomatous optic nerve head (ONH) include retinal ganglion cell axon loss and extracellular matrix (ECM) remodeling of the lamina cribrosa layer. Transforming growth factor‐β (TGF‐β) is an important pro‐fibrotic modulator of ECM metabolism, whose levels are elevated in human POAG lamina cribrosa tissue compared with non‐glaucomatous controls. We hypothesize that in POAG, lamina cribrosa (LC) glial cells respond to elevated TGF‐β, producing a remodeled ONH ECM. Using Affymetrix microarrays, we report the first study examining the effect of TGF‐β1 on global gene expression profiles in glial fibrillary acidic acid (GFAP)‐negative LC glial cells in vitro. Prominent among the differentially expressed genes were those with established fibrogenic potential, including CTGF, collagen I, elastin, thrombospondin, decorin, biglycan, and fibromodulin. Independent TaqMan and Sybr Green quantitative PCR analysis significantly validated genes involved in regulation of cell proliferation (platelet‐derived growth factor [PDGF‐α]), angiogenesis (vascular endothelial growth factor [VEGF]), ECM accumulation and degradation (CTGF, IL‐11, and ADAMT‐S5), and growth factor binding (ESM‐1). Bioinformatic analysis of the ESM‐1 promoter identified putative Smad and Runx transcription factor binding sites, and luciferase assays confirmed that TGF‐β1 drives transcription of the ESM‐1 gene. TGF‐β1 induces expression and release of ECM components in LC cells, which may be important in regulating matrix remodeling in the lamina cribrosa. In disease states such as POAG, the LC cell may represent an important pro‐fibrotic cell type and an attractive target for novel therapeutic strategies. © 2005 Wiley‐Liss, Inc.
The Importance of Lake Morphometry for the Structureand Function of Lakes
Authors: Håkanson Lars
Published: July 2005

This work demonstrates quantitatively and in a comprehensive way that the size and form of lakes regulate many general transport processes, such as sedimentation, resuspension, diffusion, mixing, burial and outflow, which in turn regulate many abiotic state variables, such as concentrations of phosphorus, suspended particulate matter, many water chemical variables and water clarity, which in turn regulate primary production, which regulate secondary production, for example of zooplankton and fish. Such relationships are discussed not qualitatively but quantitatively using a new generation of validated dynamic ecosystem models (LakeWeb and LakeMab) based on mechanistic principles. It has been shown by critical model tests (including blind tests using data covering wide limnological ranges) that these models give predictions that agree well with empirical data. This should lend credibility to the results presented in this work, which would have been very difficult to obtain using traditional methods with extensive field studies in a few lakes. Simulations have been carried out where the inflow of phosphorus is held constant and the consequences simulated for small, large, shallow and deep lakes. There are striking differences in total phosphorus (TP) concentrations and trophic state (from 10 to 100 µg TP/l) and hence also in changes in many variables characterizing lake structure and function, such as Secchi depth, suspended particulate matter, pH, water temperature, chlorophyll, algal volume, macrophyte cover; as well as production and biomasses of benthic algae, bacterioplankton, macrophytes, herbivorous zooplankton, predatory zooplankton, zoobenthos, prey fish and predatory fish. These changes have been quantified in a comprehensive manner in this work and the approach to calculate such changes are basic for an understanding of how different lakes react to changes in nutrient loading (eutrophication). (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Adsorbed layers of oriented fibronectin: A strategy to control cell–surface interactions
Authors: Calonder Claudio , Matthew Howard W. T. , Van Tassel Paul R.
Published: July 2005

Fibronectin (Fn) is a matrix protein known to induce cell attachment and spreading through its cell binding site and related synergy sites. Fn‐coated surfaces are therefore useful in tissue engineering and other cell contacting applications, but a problem with many immobilization strategies is a random distribution of molecular orientations. We sought to control Fn orientation, and thus enhance the availability of its cell binding site, by immobilizing Fn via a carboxymethyl dextran layer onto which are chemically attached monoclonal antibodies specific to a region near to Fn's C terminus (and thus away from the cell binding site). Using optical waveguide lightmode spectroscopy, we show the presence of chemically coupled antibodies to yield a considerably denser and thicker Fn layer, consistent with a more vertically aligned protein. Human umbilical vein endothelial cells spread significantly faster, and in a more spherically symmetric way, on an oriented Fn layer (i.e., in the presence of immobilized monoclonal antibodies) as compared with a control Fn layer (i.e., in the absence of bound antibodies). However, we observe human umbilical vein endothelial cell spreading on the oriented Fn layer to be similar to that on a Fn layer in the absence of a carboxymethyl dextran layer, suggesting that although orienting Fn is a promising strategy, coupling strategies using linkers other than dextran may be needed. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Structural evaluation of radially expandable cardiovascular stents encased in a polyurethane film
Authors: Trigwell Steve , De Samiran , Sharma Rajesh , Mazumder Malay K. , Mehta Jawahar L.
Published: August 2005

A method of encasing cardiovascular stents with an expandable polyurethane coating has been developed to provide a smooth homogeneous inner wall allowing for a confluent growth of endothelial cells. In this design, the metal wire stent structure is completely covered by the polyurethane film, minimizing biocorrosion of the metal (stainless steel or nitinol), and providing a homogeneous surface for surface treatment and incorporation of various eluting drugs to prevent platelet aggregation while supporting endothelialization. The polyurethane surface was treated with a helium plasma for sterilization and promotes growth of cells. The article details the performance of the coated film to expand with the metal stent up to 225% during deployment. Stress/strain behavior of polyurethane films, subsequent plasma treatment of the surface, and the adhesion of the coating to the stent structure upon expansion are presented. A film of less than 25 μm was found to be sufficient for corrosion resistance and flexibility without producing any excess stress on the stent structure. Straining the film to 225% and plasma modification did not affect the mechanical and surface properties, but allowed for improved biocompatibility as determined by the critical surface tension, surface chemistry, and roughness. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Role of HER‐2/neu signaling in sensitivity to tumor necrosis factor‐related apoptosis‐inducing ligand: Enhancement of TRAIL‐mediated apoptosis by amiloride
Authors: Kim Ki M. , Lee Yong J.
Published: July 2005

Tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL) has been shown to induce apoptosis in numerous transformed cell lines but not in most normal cells. Although this selectivity offers a potential therapeutic application in cancer, not all cancers are sensitive to TRAIL‐mediated apoptosis. In this study, we observed that amiloride, a current clinically used diuretic drug, which had little or no cytotoxicity, sensitized TRAIL‐resistant human prostate adenocarcinoma LNCaP and human ovarian adenocarcinoma SK‐OV‐3 cells. The TRAIL‐mediated activation of caspase, and PARP cleavage, were promoted in the presence of amiloride. Western blot analysis showed that combined treatment with TRAIL and amiloride did not change the levels of TRAIL receptors (DR4, DR5, and DcR2) and anti‐apoptotic proteins (FLIP, IAP, and Bcl‐2). However, amiloride dephosphorylated HER‐2/neu tyrosine kinase as well as Akt, an anti‐apoptotic protein. Interestingly, amiloride also dephosphorylated PI3K and PDK‐1 kinases along with PP1α phosphatase. In vitro kinase assay revealed that amiloride inhibited phosphorylation of kinase as well as phosphatase by competing with ATP. Taken together, the present studies suggest that amiloride enhances TRAIL‐induced cytotoxicity by inhibiting phosphorylation of the HER‐2/neu‐PI3K‐Akt pathway‐associated kinases and phosphatase. © 2005 Wiley‐Liss, Inc.
Enhancing crop yields in the developing countries through restoration of the soil organic carbon pool in agricultural lands
Authors: Lal R.
Published: August 2005

Food production in developing countries, estimated at 1223 million metric tons (Mg), must be increased by 778 million Mg or 2·5 per cent y−1 between 2000 and 2025 to meet the needs of an increased population and projected change in diet. Among numerous options, the one based on enhancing soil quality and agronomic productivity per unit area through improvement in soil organic carbon pool has numerous ancillary benefits. The available data show that crop yields can be increased by 20–70 kg ha−1 for wheat, 10–50 kg ha−1 for rice, and 30–300 kg ha−1 for maize with every 1 Mg ha−1 increase in soil organic carbon pool in the root zone. Adoption of recommended management practices on agricultural lands and degraded soils would enhance soil quality including the available water holding capacity, cation exchange capacity, soil aggregation, and susceptibility to crusting and erosion. Increase in soil organic carbon pool by 1 Mg ha−1 y−1 can increase food grain production by 32 million Mg y−1 in developing countries. While advancing food security, this strategy would also off‐set fossil fuel emissions at the rate of 0·5 Pg C y−1 through carbons sequestration in agricultural soils of developing countries. Copyright © 2005 John Wiley & Sons, Ltd.
Reservoirs in Tigray (Northern Ethiopia): characteristics and sediment deposition problems
Authors: Haregeweyn N. , Poesen J. , Nyssen J. , De Wit J. , Haile M. , Govers G. , Deckers S.
Published: August 2005

In Tigray (Northern Ethiopia, significant achievements were made, mainly from 1994 to 2002), on the development of agriculture through irrigation by employing seasonally harvested runoff using earth dams. However, most of the implemented schemes are not serving the intended purpose well because of constraints associated with both pre‐ and post‐implementation. Sediment deposition in reservoirs is a serious off‐site consequence of soil erosion in the region. However, the extent of the problem is not well studied. Moreover, there are no sufficient and reliable sediment‐yield data for Northern Ethiopia, which are important for designing new reservoirs and for implementing soil conservation practices. This study addresses those problems by undertaking: (1) a survey and evaluation of the general characteristics and problems of 54 recently built reservoirs and the characteristics of their respective catchments; and (2) a detailed sediment survey in ten reservoirs and related catchment characteristics. A field survey in 2002–2003, a review of technical reports and interviews were the bases for this study.

Most of the reservoirs are under risk of insufficient inflow, excessive seepage and sediment deposition. These problems are mainly attributed to the use of a poor database on hydrology and sediment yield, and the lack of adaptable methodologies for assessing controlling factors at the planning stage.

The reservoir survey, which is the first of its kind in Ethiopia, also indicates that specific sediment yield (SSY) varies significantly between catchments: i.e. from 237 to 1817 t km−2 y−1 with an average of 909 ( ± 500) t km−2 y−1. The high spatial variability is mainly associated with differences in lithology, cover, extent of gully network and human activities. Therefore, adapting an average SSY value for the whole region is not recommended for future planning purposes. The sediment deposition problem is significant: i.e. 70 per cent of the study reservoirs have important siltation problems so that they will end their useful life well before the dam design period. Hence, sediment management in reservoirs could be an effective approach towards maintaining the existing storage capacity.

For the realization of sustainable land and water development in Tigray, sufficient and reliable database building, development and standardization of appropriate methodologies for predicting sediment yield and capacity building of designers needs to be given top priority. Moreover, awareness creation among policy makers, donors and beneficiaries is also important for action. Copyright © 2005 John Wiley & Sons, Ltd.
Hybrid Nanogels with Physical and Chemical Cross‐Linking Structures as Nanocarriers
Authors: Morimoto Nobuyuki , Endo Takao , Ohtomi Michiko , Iwasaki Yasuhiko , Akiyoshi Kazunari
Published: August 2005

Summary: Polymerizable nanogels were prepared by self‐assembly of cholesteryl group‐bearing pullulan (CHP) with methacryloyl groups (CHPMA). The CHPMA nanogel was polymerized with 2‐methacryloyloxyethyl phosphorylcholine (MPC) by radical polymerization in dilute aqueous solution. The solution properties of the polymers in water were investigated by TEM, SEC‐MALS, and fluorescence quenching technique. Monodispersed hybrid nanogels of CHPMA‐MPC (CM nanogels) (25–30 nm in radius of gyration) were obtained by using CHPMA nanogel as a seed‐nanogel. CM nanogels have a dual cross‐linking structure that is physically cross‐linked with the cholesteryl groups and chemically cross‐linked with the MPC polymer chains. CM nanogels trap heat‐denatured carbonic anhydrase B (CAB) and prevent their aggregations. The nanogels maintained the ability of trapping and releasing enzymes by host‐guest interaction of cholesteryl group and cyclodextrin.

Schematic illustration of hybrid nanogel preparation.

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Schematic illustration of hybrid nanogel preparation.
Temperature Sensitive Behavior of Poly(N‐isopropylacrylamide) Grafted Onto Electron Beam‐Irradiated Poly(propylene)
Authors: Bucio Emilio , Burillo Guillermina , Adem Esbaide , Coqueret Xavier
Published: July 2005

Summary: N‐Isopropylacrylamide (NIPAAm) was graft‐polymerized from its acetone solution onto poly(propylene) (PP) films, after electron‐beam irradiation in the presence of air oxygen. The effects of pre‐irradiation dose as well as monomer concentration, reaction temperature and reaction time on the grafting efficiency were investigated. Typical conditions for achieving maximum grafting yield were observed for 1 M monomer concentration, after PP pre‐irradiation with a 300 kGy dose and a reaction temperature of 50 °C. The location of the graft polymerization was examined by different methods including measurements of dimensional variations, calorimetry, SEM and AFM. The temperature‐responsive behavior of grafted copolymer was studied by swelling and contact angle measurements at different temperatures.

Temperature dependence of the swelling ratio in water as a function of temperature.

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Temperature dependence of the swelling ratio in water as a function of temperature.
Swelling Behavior and Complex Formation Ability of Ternary Amphoteric Gels based on Allylamine Derivatives and Maleic Acid
Authors: Ibraeva Zhanar E. , Hahn Mathias , Jaeger Werner , Laschewsky Andre , Bimendina Larisa A. , Kudaibergenov Sarkyt E.
Published: August 2005

Summary: The swelling behavior of an amphoteric gel composed of 50 mol‐% of maleic acid (MA), 25 mol‐% of N,N′‐dimethyldiallylammonium chloride (DMDAAC) and 25 mol‐% of diallylamine (DAA) was studied in aqueous and aqueous‐salt solutions. The isoelectric point (IEP) of the MA‐DMDAAC‐DAA gel determined from swelling experiments was about pH 4.6. Considerable gel swelling with increasing ionic strength was observed at the IEP. Dynamic swelling properties of the amphoteric gel in water with and without added salt were measured at various pH values including the IEP. The swelling behavior of the amphoteric gel was found to depend on the ionization state of the functional groups. It can be described by either a relaxation‐controlled or non‐Fickian (anomalous) mechanism. Swelling‐deswelling properties of the amphoteric gel were also studied in mixtures of water and organic solvents. The amphoteric gel was able to complex sodium poly(styrene sulfonate), sodium lauryl sulfate, the cationic drug richlocain, and the bivalent transition metal ions Cu2+, Ni2+, Co2+, and Zn2+. The sorption of polyelectrolyte, surfactant, drug, and metal ions by the amphoteric gel is accompanied by the contraction of the gel network. Partial release of the cationic drug molecules entrapped into the gel volume takes place at the IEP of the amphoteric gel with low activation energy, while neither the anionic polyelectrolyte nor the surfactants are released from the gel interior at the IEP. The swelling‐shrinking behavior of gel‐polyelectrolyte and gel‐surfactant complexes in dependence of pH and ionic strength of the outer solution is similar.

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Copolymerization of Propene and 5‐Vinyl‐2‐Norbornene: A Simple Route to Polar Poly(propylene)s
Authors: Sarazin Yann , Fink Gerhard , Hauschild Klaus , Bochmann Manfred
Published: July 2005

Summary: The metallocenes rac‐C2H4(Ind)2ZrCl2 (1), rac‐Me2Si(Ind)2ZrCl2 (2), and rac‐Me2Si(2‐Me‐benz[e]Ind)2ZrCl2 (3) efficiently copolymerize propene and 5‐vinyl‐2‐norbornene (VNB). 1 and 2 give a high VNB content and high productivities, whereas 3 gives moderate incorporation. Surprisingly, precatalysts 1 and 2, which have very closely related structures, showed very different reactivities toward VNB, with 1 having a greater affinity for VNB than for propene. The copolymers are quantitatively converted into polyolefins with polar functionalities.

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Novel Cross‐Linked Films Prepared from Hyperbranched Poly(amine‐ester)
Authors: Wei Xiu‐Zhen , Zhu Bao‐Ku , Xiao Ling , Xu You‐Yi , Geckeler Kurt E.
Published: July 2005

Summary: Novel hyperbranched poly(amine‐ester) (HPAE) cross‐linked films were prepared by cross‐linking the terminal hydroxyl groups of HPAE using glutaraldehyde (GA). Atom force microscope and scanning electron microscope revealed their smooth surfaces, dense and homogenous matrices. Property characterizations indicated that these cross‐linked films had good hydrophilicity, relative low protein adsorption, and high tensile strength. Also, their swelling behavior varied with the solvent.

Structure of the hyperbranched poly(amine‐ester).

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Structure of the hyperbranched poly(amine‐ester).
Synthesis and Characterization of Helix‐Coil Diblock Copolymers with Controlled Supramolecular Architectures in Aqueous Solution
Authors: Zhang Jie , Yu Zhenning , Wan Xinhua , Chen Xiaofang , Zhou Qifeng
Published: July 2005

Summary: A series of helix‐coil diblock copolymers based on poly(ethylene oxide) and optically active helical poly{(+)‐2,5‐bis[4′‐((S)‐2‐methylbutoxy)phenyl]styrene} (PMBPS) were synthesized via atom transfer radical polymerization (ATRP). The synthetic methodology permitted straightforward preparation of the diblock copolymers with relatively low polydispersities and a broad range of compositions and molecular weights. Depending on the composing block length and the initial concentration, the copolymers self‐assembled into different supramolecular structures in aqueous solution, including spherical micelles, vesicles, multilamellar vesicles, large compound vesicles, and tubules.

Schematic representation of the synthesis of PEO‐b‐PMBPS block copolymers and their aggregation in aqueous solution.

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Schematic representation of the synthesis of PEO‐b‐PMBPS block copolymers and their aggregation in aqueous solution.
Propagation of a hydraulic fracture parallel to a free surface
Authors: Zhang X. , Jeffrey R. G. , Detournay E.
Published: July 2005

This paper analyses the plane strain problem of a fracture, driven by injection of an incompressible viscous Newtonian fluid, which propagates parallel to the free surface of an elastic half‐plane. The problem is governed by a hyper‐singular integral equation, which relates crack opening to net pressure according to elasticity, and by the lubrication equations which describe the laminar fluid flow inside the fracture. The challenge in solving this problem results from the changing nature of the elasticity operator with growth of the fracture, and from the existence of a lag zone of a priori unknown length between the crack tip and the fluid front. Scaling of the governing equations indicates that the evolution problem depends in general on two numbers, one which can be interpreted as a dimensionless toughness and the other as a dimensionless confining stress. The numerical method adopted to solve this non‐linear evolution problem combines the displacement discontinuity method and a finite difference scheme on a fixed grid, together with a technique to track both crack and fluid fronts. It is shown that the solution evolves in time between two asymptotic similarity solutions. The small time asymptotic solution corresponding to the solution of a hydraulic fracture in an infinite medium under zero confining stress, and the large time to a solution where the aperture of the fracture is similar to the transverse deflection of a beam clamped at both ends and subjected to a uniformly distributed load. It is shown that the size of the lag decreases (to eventually vanish) with increasing toughness and compressive confining stress. Copyright © 2005 John Wiley & Sons, Ltd.
A unified formulation for continuum mechanics applied to fluid–structure interaction in flexible tubes
Authors: Greenshields C. J. , Weller H. G.
Published: July 2005

This paper outlines the development of a new procedure for analysing continuum mechanics problems with a particular focus on fluid–structure interaction in flexible tubes. A review of current methods of fluid–structure coupling highlights common limitations of high computational cost and solution instability. It is proposed that these limitations can be overcome by an alternative approach in which both fluid and solid components are solved within a single discretized continuum domain. A single system of momentum and continuity equations is therefore derived that governs both fluids and solids and which are solved with a single mesh using finite volume discretization schemes. The method is validated first by simulating dynamic oscillation of a clamped elastic beam. It is then applied to study the case of interest—wave propagation in highly flexible tubes—in which a predicted wave speed of 8.58 m/s falls within 2% of an approximate analytical solution. The method shows further good agreement with analytical solutions for tubes of increasing rigidity, covering a range of wave speeds from those found in arteries to that in the undisturbed fluid. Copyright © 2005 John Wiley & Sons, Ltd.
The risk of cancer in twins: A report from the childhood cancer survivor study
Authors: Kadan‐Lottick Nina S. , Kawashima Toana , Tomlinson Gail , Friedman Debra L. , Yasui Yutaka , Mertens Ann C. , Robison Leslie L. , Strong Louise C.
Published: August 2005

Background

Twin concordance studies help evaluate the contribution of genetic factors in childhood cancers, but previous reports have primarily focused on leukemia because of the rarity of other malignancies. In the current report, a large cohort of childhood cancer survivors was used to: (1) describe twin concordance patterns for a range of cancers, (2) calculate the standardized incidence rates of cancers in twins, and (3) describe clinical features and outcomes of concordant twins.

Procedure

Cancer family history was obtained on the 211 twins participating in the Childhood Cancer Survivor Study (CCSS) (14,352 participants surviving ≥5 years after a malignancy diagnosed at <21 years during January 1, 1970–December 31, 1986) to calculate probandwise twin concordance rates and standardized incidence ratios (SIRs) using Surveillance, Epidemiology, and End‐Results data.

Results

Seven monozygotic twin pairs were concordant for cancer (six for leukemia, one for non‐Hodgkin lymphoma), yielding probandwise concordance rates of 9.5%, 20.7%, and 20.0% for all cancer, leukemia, and non‐Hodgkin lymphoma (NHL), respectively. No concordance was observed among dizygotic twins or for dissimilar cancers. The SIR in monozygotic twins was 23.3 (95% CI = 11.1–48.9) for all cancer, 112.4 (95% CI = 50.5–250.1) for leukemia, and 40.5 (5.7–287.5) for NHL. Concordant twins were similar in age at diagnosis and vital status.

Conclusions

Twin concordance for cancer is largely restricted to monozygotic twins and hematological malignancies, consistent with in utero malignancy transmission demonstrated by others. Our data support clinical monitoring of the twins of cases with hematological malignancies, and does not contribute evidence for genetic factors in other cancers. Pediatr Blood Cancer 2006, 46:476–481. © 2005 Wiley‐Liss, Inc.
Prolonged QT interval in pediatric sickle cell disease
Authors: Mueller Brigitta U. , Martin Kahlil J. , Dreyer William , Bezold Louis I. , Mahoney Donald H.
Published: August 2005

We recently cared for a patient with sickle cell disease (SCD) who presented with cardiac arrest and was found to have a prolonged corrected QT interval (QTc). This prompted us to perform a retrospective review of all electrocardiograms performed in patients with SCD during the last two years. Among 142 patients with ECG results, we identified 12 patients (8 males and 4 females), who had one or more documented measurements of prolonged QTc intervals. The relatively high prevalence of borderline or moderately prolonged QTc intervals in our patient population warrants further investigation. Pediatric Blood Cancer 2006;47:831–833. © 2005 Wiley‐Liss, Inc.
Utility of electrophoretically derived protein mass estimates as additional constraints in proteome analysis of human serum based on MS/MS analysis
Authors: Kim Jin Young , Lee Jeong Hwa , Park Gun Wook , Cho Kun , Kwon Kyung‐Hoon , Park Young Mok , Cho Sang Yun , Paik Young‐Ki , Yoo Jong Shin
Published: July 2005

The proteome of a HUPO human serum reference sample was analyzed using multidimensional separation techniques at both the protein and the peptide levels. To eliminate false‐positive identifications from the search results, we employed a data filtering method using molecular weight (MW) correlations derived from denaturing 1‐DE. First, the six most abundant serum proteins were removed from the sample using immunoaffinity chromatography. 1‐DE was then used to fractionate the remaining serum proteins according to the MW. Gel bands were isolated and in‐gel digested with trypsin, and the resulting peptides were analyzed by 2‐D LC/ESI‐MS/MS. A SEQUEST search using the MS/MS results identified 494 proteins. Of these, 202 were excluded formally using protein data filtering as they were single‐assignment proteins and their theoretical and electrophoretically‐derived MWs did not correlate at high confidence. To evaluate this method, the results were compared with those of 1‐D LC/MALDI‐TOF/TOF and HUPO Plasma Proteome Project analyses. Our data filtering approach proved valuable in analysis of complex, large‐scale proteomes such as human serum.
Novel active ester‐bridged copolynorbornene materials containing terminal functional hydroxyl, amino, methacryloyl, or ammonium groups via ring‐opening metathesis polymerization
Authors: Liaw Der‐Jang , Chen Tsang‐Pin , Huang Ching‐Cheng
Published: August 2005

Several random and block copolynorbornenes with side chains containing terminal hydroxyl, amino, methacryloyl or ammonium groups were derived from the functional alkyl ester‐containing norbornenes by ring‐opening metathesis polymerization (ROMP). The main chain of ROMP‐type polynorbornene had a more important role for glass‐transition temperature in comparison with vinyl addition polymerization. There is little effect on glass‐transition temperature (about −39 °C) of polynorbornenes with different length of alkyl side chain. The organosoluble copolynorbornenes with active crosslinkable methylacryloyl side chains derived from functional hydroxyl group were prepared to improve the thermal stability of poly(methyl methacrylate) [decomposition temperature (Td)10% = 325 °C in nitrogen] by forming networked AB crosslinked polymer (T = 367 °C in nitrogen). The sizes of nanometer‐scale polymeric micelles of block copolymers having hydrophobic alkyl ester and hydrophilic ammonium groups were measured in the range of 11–25 nm by scanning electron microscopy. These polymeric materials with various functional groups or amphiphilic architectures are accessible by ROMP, whose topology makes them particularly attractive for application potential such as biomedical and photoelectric materials. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4233–4247, 2005
Ethylene and propylene polymerization with bis(indenyl)zirconium/Mao catalytic systems modified by sterically demanding alcohols
Authors: Firme Caio L. , Grafov Andrei V. , Dias Marcos L.
Published: August 2005

Ethylene and propylene polymerization using Ind2ZrCl2 and Ind2Zr(CH3)2/MAO catalytic systems modified by the sterically demanding bridged alicyclic alcohols, adamantan‐1‐ol, adamantan‐2‐ol, 2‐methyladamantan‐2‐ol, and fenchyl alcohol, was investigated. Lower alcohols like isopropanol completely deactivate the system, whereas in the case of catalysts modified by these voluminous alcohols only a slight decrease in the catalytic activity proportional to alcohol/metallocene molar ratio was observed. The addition of the modifiers gives rise to polymers with higher molecular weights than the nonmodified systems, but no structural changes in the polyethylenes were observed. The addition of the sterically demanding alcohols to the reaction medium changes the regioregularity of polypropylenes, but does not significantly influence their stereoregularity, at 30 °C. Propylene–ethylene copolymers containing up to 8.6% of ethylene units derived from 1,3‐insertion and significant amount of rr‐centered pentads were obtained by single‐monomer polymerization of propylene with Ind2ZrCl2/MMAO/adamantan‐1‐ol, at 70 °C. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4248–4259, 2005
A modified UNIFAC model for the prediction of phase equilibrium for polymer solutions
Authors: Liu Qing Lin , Cheng Zhen Feng
Published: July 2005

A new simple activity coefficient model for the prediction of solvent activities in polymer solutions is presented. The model consists of three terms, the combinatorial and the residual terms, which are taken from UNIFAC model, and a free‐volume term derived from the van der Waals partition function with the mixed volume, the mixed free‐volume and the mixed c‐value being supposed to be given by linear mixing rules. Twenty‐one polymer solution systems were used to test the applicability of the present model. Compared with the UNIFAC‐FV, Entropic‐FV, and Entropic‐FV‐1.2 models, it is found that the model proposed in this work can produce better results than those from the other three models. Furthermore, the model is valid for a broad range of polymer concentration and a wide range of temperature. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2541–2547, 2005
Rheology of concentrated blends with immiscible components
Authors: Yu Wei , Zhou Chixing , Xu Yuanze
Published: July 2005

The rheology and morphology evolution of nondilute and concentrated immiscible blends were investigated in this paper. A theoretical model was established by a Hamiltonian formalism. The interactions between droplets were integrated in the morphology‐dependent drag coefficient. The phenomenological parameters in the model were determined by the comparisons with the dilute emulsion model and the Krieger–Dougherty model. The model showed better predictions in the shear viscosity and first normal stress difference than that of the dilute emulsion model. The effects of volume fraction on droplet deformation were also predicted and compared with the numerical simulations. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2534–2540, 2005
Rheological characterization and microphase‐separated structure of a poly(ether‐block‐amide) segmented block copolymer
Authors: Yang I‐Kuan , Tsai Ping‐Hung
Published: July 2005

Melt of a segmented block copolymer having poly(lauryl lactam) as the hard segment and poly(tetramethylene oxide) as the soft segment was investigated by rheological techniques. Storage modulus of the polymer melt exhibits the nonterminal behavior resembling those of diblock and triblock copolymer melts, indicating the existence of a microphase‐separated structure. Contrary to block copolymers, the melt of the segmented block copolymer changes from a weak structure to a stiff one upon raising temperature. The storage modulus of the weak structure at low temperatures is inert to large‐amplitude oscillatory shear, while the oscillatory shear destroys the stiff structure at high temperatures and reduces its storage modulus to a value that is same as that of the weak structure. The tapping‐mode data of atomic force microscopy reveal that at low temperatures the polymer melt exhibits a biphasic structure consisted of small spherical soft domains dispersed in a slightly harder matrix; and at high temperatures the spherical domain structure preserves, though the domain coarsens and the hardness difference between the domain and the matrix enlarges. Infrared spectrum analysis shows that the temperature‐induced structural change is related to the dissociation of hydrogen bonding between the hard and soft segments. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2557–2567, 2005
Coupling between conformation and proton binding in proteins
Authors: Vila Jorge A. , Ripoll Daniel R. , Arnautova Yelena A. , Vorobjev Yury N. , Scheraga Harold A.
Published: August 2005

Interest centers here on whether the use of a fixed charge distribution of a protein solute, or a treatment that considers proton‐binding equilibria by solving the Poisson equation, is a better approach to discriminate native from non‐native conformations of proteins. In this analysis of the charge distribution of 7 proteins, we estimate the solvation free energy contribution to the total free energy by exploring the 2ζ possible ionization states of the whole molecule, with ζ being the number of ionizable groups in the amino acid sequence, for every conformation in the ensembles of 7 proteins. As an additional consideration of the role of electrostatic interactions in determining the charge distribution of native folds, we carried out a comparison of alternative charge assignment models for the ionizable residues in a set of 21 native‐like proteins. The results of this work indicate that (1) for 6 out of 7 proteins, estimation of solvent polarization based on the Generalized Born model with a fixed charge distribution provides the optimal trade‐off between accuracy, with respect to the Poisson equation, and speed when compared to the accessible surface area model; for the seventh protein, consideration of all possible ionization states of the whole molecule appears to be crucial to discriminate the native from non‐native conformations; (2) significant differences in the degree of ionization and hence the charge distribution for native folds are found between the different charge models examined; (3) the stability of the native state is determined by a delicate balance of all the energy components, and (4) conformational entropy, and hence the dynamics of folding, may play a crucial role for a successful ab initio protein folding prediction. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Electrochemical detection of indoles at diamond electrodes
Authors: Foord John S. , Chatterjee Arnab
Published: July 2005

Indoles represent an important class of chemical compounds, of biological significance, and various attempts have been made to develop electrochemical sensors for their detection. In general, this has failed because of the electrode fouling which tends to occur when conventional electrode materials are employed, so we have explored the use of diamond electrodes, in view of their known resistance to electrode poisoning. High phase purity boron‐doped diamond electrodes show no detectable oxidative signal when used in solutions containing indole‐3‐methanol or 1‐methyl indole. However, indole oxidation at electrode potentials greater than 0.7 V vs. SCE is seen if lower purity diamond or nanodiamond electrodes are employed. Electrode fouling is found to be problematic, but significantly better than at pyrolytic graphite electrodes. The oxidation of tryptophan at high phase purity diamond electrodes is seen, indicating that in general the indole oxidation chemistry is dependent both on the type of diamond electrode used, and the particular indole involved. Sensitive detection of tryptophan at micromolar concentrations is observed without electrode fouling, although electrode passivation is seen in concentrated tryptophan solutions. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Methyl radical beam sources for ultra high vacuum applications
Authors: Gehin T. , Wallart X. , Vignaud D.
Published: July 2005

Methyl radical beam sources for ultra high vacuum applications have been characterised using ionisation threshold mass spectrometry. Methane, ethane and acetone have been dissociated in a resistively heated carbon gas cracker cell. The effect of pressure on the methyl radicals formation has been studied independently of the precursor gas flow by changing the cell conductance. Methyl radical fluxes heavily depend on the pressure and the nature of precursor, ranging from 1 × 1015 cm–2 s–1 for a methane flow of 1 sccm up to 2 × 1016 cm–2 s–1 when acetone is used. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of vacancy related defects in diamond
Authors: Hounsome L. S. , Jones R. , Martineau P. M. , Shaw M. J. , Briddon P. R. , Öberg S. , Blumenau A. T. , Fujita N.
Published: July 2005

〈110〉 vacancy chains, multi‐vacancy clusters and vacancy discs have been modeled using density functional theory within the AIMPRO and DFTB codes. While a connection can be established between the results on vacancy chains and previous EPR experiments, no connection can be made between the point defects and the optical properties of natural type IIa brown diamonds. However, a vacancy disc consisting of a {111} double plane of vacancies is stable and possesses an absorption spectrum similar to that found in brown diamonds. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrochemical characterization of intrinsic hydrogen terminated single crystalline CVD diamond
Authors: Shin D. , Watanabe H. , Nebel C. E.
Published: July 2005

Cyclic voltammetry experiments have been performed on high quality intrinsic hydrogen terminated single crystalline CVD diamond to characterize the electron transfer at the interface of the diamond/redox‐electrolyte system. In vacuum these diamond films are insulating, but immersed into electrolyte solutions which contain Fe(CN)63–/4– or Ru(NH3)62+/3+ generates insulator–metal transition. The two redox systems have chemical potentials below the valence‐band maximum EVBM as calculated from the formal potentials. The same experiments applied with methyl viologen (MV) as redox couple results in no detectable electron exchange. MV has two levels, but both are above EVBM. The reversible electron exchange with Fe(CN)63–/4– or Ru(NH3)62+/3+ is rate limited, as peaks are broadened and shifted to higher and lower potentials. The results are compared with data available in the literature for high quality H‐terminated boron doped (metallic) polycrystalline diamond which shows that the formal potentials are basically comparable. Electrochemical oxidation terminates the experiments as the surface conductivity is removed and films become highly resistive. The results are discussed using the transfer‐doping and the Marcus‐Gerischer models for interpretation. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Peculiarities of thermopower in Bi microwires at low temperatures
Authors: Gitsu D. , Huber T. , Konopko L. , Nikolaeva A.
Published: July 2005

The temperature dependence (4.2–300 K) of the thermopower of thin Bi wires was investigated. The cylindrical Bi crystals ranging in size from 0.19 to 3 µm were prepared by high‐frequency liquid‐phase casting in a glass capillary. The nanowires are single crystal and are oriented with the (1011) crystalline axis along the wire axis. For temperatures below ∼12 K the thermopower is dominated by phonon drag and a maximum is observed at around 6 K. The position of this maximum and its value depends on the wire's diameter and the length of the samples. In the temperature range 8–11 K the phonon‐drag contribution follows an exponential temperature dependence that is characteristic of a two‐stage mechanism. The positive thermopower maxima of the order of 10 µV K–1 are explained in terms of the phonon drag of carriers. Several mechanisms that may account for the data are discussed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sequence determination in aliphatic poly(ester amide)s by matrix‐assisted laser desorption/ionization time‐of‐flight and time‐of‐flight/time‐of‐flight tandem mass spectrometry
Authors: Rizzarelli Paola , Puglisi Concetto , Montaudo Giorgio
Published: August 2005

Poly(ester amide)s from dimethyl sebacate or sebacic acid and 2‐aminoethanol or 4‐amino‐1‐butanol were characterized by post‐source decay matrix‐assisted laser desorption/ionization time‐of‐flight (PSD‐MALDI‐TOF) and time‐of‐flight/time‐of‐flight tandem mass spectrometry (MALDI‐TOF/TOF‐MS/MS). Sodiated oligomers were selected as precursor ions for dissociation studies. PSD analysis was performed on dimethyl sebacate, dicarboxylic, carboxylic and amino alcohol, and diamino alcohol terminated oligomers. PSD‐MALDI‐TOF mass spectra yielded information on the fragmentation mechanisms of the poly(ester amide) chains, showing that the main cleavages proceed through a β‐hydrogen transfer rearrangement. MALDI‐TOF/TOF‐MS/MS provided structural information concerning ester/amide sequences in the polymer chains. As expected, together with the ions appearing in the PSD‐MALDI mass spectrum, several new abundant fragment ions in the low‐mass range are present in MALDI‐TOF/TOF‐MS/MS spectra. These new product ions proved to be diagnostic and made it possible to establish the presence of random sequences of ester and amide bonds in the poly(ester amide)s samples. Copyright © 2005 John Wiley & Sons, Ltd.