bluuebunny/crossref_metadata_2025 huggingface dataset:
Developmental constraints vs. variational properties: how pattern formation can help to understand evolution and development
Authors: Salazar‐Ciudad Isaac
Published: October 2005

This article suggests that apparent disagreements between the concept of developmental constraints and neo‐Darwinian views on morphological evolution can disappear by using a different conceptualization of the interplay between development and selection. A theoretical framework based on current evolutionary and developmental biology and the concepts of variational properties, developmental patterns and developmental mechanisms is presented. In contrast with existing paradigms, the approach in this article is specifically developed to compare developmental mechanisms by the morphological variation they produce and the way in which their functioning can change due to genetic variation. A developmental mechanism is a gene network, which is able to produce patterns in space though the regulation of some cell behaviour (like signalling, mitosis, apoptosis, adhesion, etc.). The variational properties of a developmental mechanism are all the pattern transformations produced under different initial and environmental conditions or IS‐mutations. IS‐mutations are DNA changes that affect how two genes in a network interact, while T‐mutations are mutations that affect the topology of the network itself. This article explains how this new framework allows predictions not only about how pattern formation affects variation, and thus phenotypic evolution, but also about how development evolves by replacement between pattern formation mechanisms. This article presents testable inferences about the evolution of the structure of development and the phenotype under different selective pressures. That is what kind of pattern formation mechanisms, in which relative temporal order, and which kind of phenotypic changes, are expected to be found in development. J. Exp. Zool. (Mol. Dev. Evol.) 306B, 2006. © 2005 Wiley‐Liss, Inc.
Erythromycin inhibits wear debris‐induced inflammatory osteolysis in a murine model
Authors: Ren Weiping , Wu Bin , Peng Xin , Mayton Lois , Yu Dongzi , Ren JuanJie , Chen Ben D. , Wooley Paul H.
Published: October 2005

Up to 20% of patients with total joint arthroplasty will develop radiographic evidence of aseptic loosening (AL), which most likely results from an inflammatory response to billions of wear debris shed from the implant. Our previous work has demonstrated that erythromycin (EM), a macrolide antibiotic, inhibits wear debris‐induced inflammatory osteoclastogenesis through the reduction of cytokine production and osteoclast differentiation, both of which involve the NF‐κB pathway. The aim of the current study was to determine whether EM inhibits wear debris‐induced inflammatory osteolysis in a murine osteolysis model. Ultrahigh molecular‐weight polyethylene (UHMWPE) debris was introduced into established air pouches on BALB/c mice, followed by implantation of calvaria bone from syngeneic littermates. EM (2 mg/kg/day) was given to mice intraperitoneally 2 days before UHMWPE introduction and maintained until the sacrifice of the mice. Mice with and without EM treatment, as well as control mice injected with saline alone were included in this study. Pouch tissues were collected 14 days after UHMWPE inoculation for molecular and histology analysis. Our findings indicate that: (1) EM reduced UHMWPE‐induced tissue inflammation, including the diminished pouch membrane thickness, reduced inflammatory cellular infiltration, and lowered IL‐1β and TNF‐α expression (mRNA and protein); (2) EM inhibited UHMWPE‐induced osteoclastogenesis, with reduced gene activation of RANK, RANKL, and CPK, and diminished RANKL expression in UHMWPE stimulated pouches, and (3) EM markedly reduced the number of TRAP+ cells in pouch tissues, and protected against bone collagen depletion. In conclusion, this study provides the evidence that EM inhibits the UHMWPE particles‐induced inflammatory osteolysis in a murine model, and represents a promising therapeutic candidate for the prevention and treatment of AL. © 2005 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Role of free radicals in aseptic loosening of hip arthroplasty
Authors: Kinov Plamen , Leithner Andreas , Radl Roman , Bodo Koppany , Khoschsorur Gholam‐Ali , Schauenstein Konrad , Windhager Reinhard
Published: October 2005

Fibrous pseudocapsule around hip implants is an invariable finding at revision operations and is believed to release inflammatory mediators that stimulate bone resorption. Reactive oxygen species have been proposed to be causative factors in various disorders with tissue fibrosis. We were interested in investigating whether aseptic loosening is connected with high oxidative stress, and in showing the underlying mechanism of periprosthetic fibrosis and its role in loosening. Levels of oxidative stress markers reduced (GSH) and oxidized (GSSG) gluthatione and malondialdehyde (MDA) were assayed in 28 loose hips and in 12 stable hips revised for high rate of wear and osteolysis. Collagen in the periprosthetic tissues was measured as hydroxyproline content. Osteolysis and polyethylene wear were graded. Increased oxidative stress measured by low GSH/GSSG ratio as well as by increased MDA level was established in patients compared to controls. Oxidative stress markers intercorrelated significantly. MDA and both GSH and GSSG levels correlated significantly with hydroxyproline level. Levels of GSSG and MDA were higher in hips with greater polyethylene wear. The results suggest that high oxidative stress may play a role in formation of a fibrous membrane observed at revision of loose hips. The fibrous pseudocapsule is probably related to high intraarticular pressure and expansion of the effective joint space. This study may elicit some aspects of the pathogenesis of aseptic hip loosening and aid in future investigations aiming at prevention of this complication. © 2005 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Effect of cyclic strain and plating matrix on cell proliferation and integrin expression by ligament fibroblasts
Authors: Hannafin Jo A. , Attia Erik A. , Henshaw Ross , Warren Russell F. , Bhargava Madhu M.
Published: October 2005

The role of cell surface integrins in cell migration, proliferation, and attachment to matrix molecules is well known. Integrin–matrix interactions have been implicated in mechanotransduction and load transmission from the outside to the inside of the cell. In this study, the effect of cyclic strain on the cell proliferation, attachment, and expression of integrin subunits β1, β3, and α5 was determined in anterior cruciate ligament (ACL) and medial collateral ligament (MCL) fibroblasts grown on polystyrene, Type I collagen, laminin, elastin, and fibronectin. ACL fibroblast proliferation was not affected by growth substrate whereas MCL cells reached confluence more rapidly on fibronectin compared with collagen or polystyrene. Exposure to 5% cyclic strain resulted in a significant decrease in ACL and MCL fibroblast proliferation on fibronectin and Type I collagen. MCL cells showed a greater strain‐dependent inhibition of cells grown on a fibronectin substrate than those grown on collagen. This matrix‐dependent effect of strain on cell proliferation was not seen with ACL cells. Attachment of ACL and MCL fibroblasts was stronger to fibronectin compared with Type I collagen, laminin, and polystyrene. In the absence of applied load, the expression of β1, β3, and α5 subunits was not substrate dependent and the expression of β1 and α5 integrin subunits was higher in MCL cells than ACL cells on all substrates. In contrast, the expression of β3 integrin subunit was higher in ACL cells than MCL cells. In response to 5% strain, β1, and α5 expression increased in all fibroblasts with MCL cells having a higher magnitude of expression. β3 expression showed a 90% increase in response to load when grown on laminin for both MCL and ACL fibroblasts and demonstrated no change in expression on Type I collagen or fibronectin. The duration of applied strain from 2 versus 22 h had no effect on cell proliferation or integrin expression. © 2005 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Ice‐cored drumlins at the surge‐type glacier Brúarjökull, Iceland: a transitional‐state landform
Authors: Schomacker Anders , Krüger Johannes , Kjær Kurt H.
Published: October 2005

This paper presents data on a glacial landform that, to our knowledge, has not previously been described in the literature: the ice‐cored drumlin. The study area is the forefield of the surge‐type glacier Brúarjökull at the northeastern margin of the Vatnajökull ice cap, East Iceland. Based on sedimentological field investigations and aerial photograph interpretation, a qualitative model for the formation of ice‐cored drumlins is proposed. The drumlin core consists of stagnant glacier ice from a previous advance and bubbly ice formed by snowdrifts, which were incorporated during the most recent advance—the 1963–64 surge. This advance deposited a mantle of basal till and streamlined the ice‐cored moraines. Till deformation and deposition on the drumlin ice‐core is facilitated by a substratum of low‐permeability ice‐cored moraines.

In the present climate, the ice‐core is subject to melting and the drumlin landform will degrade. The ongoing melting of the core and re‐sedimentation of the till cover cause the originally streamlined subglacial landform to develop into a patch of hummocky moraine surrounded by a basal till sheet. Thus, ice‐cored drumlins are a transitional‐state landform in the surging glacier landsystem at Brúarjökull rather than a ‘final’ landform. Copyright © 2005 John Wiley & Sons, Ltd.
Glacier response in the European Alps to Heinrich Event 1 cooling: the Gschnitz stadial
Authors: Ivy‐Ochs Susan , Kerschner Hanns , Kubik Peter W. , Schlüchter Christian
Published: October 2005

The Gschnitz stadial was a period of regionally extensive glacier advance in the European Alps that lies temporally between the breakdown of the Last Glacial Maximum piedmont lobes and the beginning of the Bølling warm interval. Moraines of the Gschnitz stadial are found in medium to small catchments, are steep‐walled and blocky, and reflect a snowline lowering of 650–700 m in comparison to the Little Ice Age reference snowline. 10Be surface exposure dating of boulders from the moraine at the type locality at Trins (Gschnitz valley, Tyrol, Austria) shows that it stabilised no later than 15 400 ± 1400 yr ago. The overall morphological situation and the long reaction time of the glacier suggest that the climatic downturn lasted about 500 ± 300 yr, indicating that the Gschnitz cold period began approximately 15 900 ± 1400 yr ago, if not somewhat earlier. This is consistent with published radiocarbon dates that imply that the stadial occurred sometime between 15 400 14C yr BP (18 020–19 100 cal. yr) and 13 250 14C yr BP (15 360–16 015 cal. yr). A palaeoclimatic interpretation of the Gschnitz glacier based on a simple glacier flow model and statistical glacier‐climate models shows that precipitation was about one‐third of modern‐day precipitation and summer temperatures were about 10 K lower than today. In comparison, during the Younger Dryas, precipitation in this area was only about 10% less and Ts (summer temperature) was only 3.5–4 K lower than modern values. Based on the age of the moraine and the cold and dry climate at that time, we suggest that the Gschnitz stadial was the response of Alpine glaciers to cooling of the North Atlantic Ocean associated with Heinrich Event 1. Copyright © 2005 John Wiley & Sons, Ltd.
The deglaciation of eastern Scotland: cosmogenic 10Be evidence for a Lateglacial stillstand
Authors: Everest Jeremy , Kubik Peter
Published: October 2005

Cosmogenic nuclide analysis, using 10Be, has been used to date a Lateglacial stillstand in the Eastern Highlands of Scotland at 16.6–13.6 kyr BP. The dates constrain the extent of the local Cairngorm Ice Cap and the larger Scottish Ice Sheet at a particular stage during deglaciation. The geomorphological and sedimentological evidence suggests that the glacial stillstand persisted for around 1 kyr. Independent 14C dating from Loch Etteridge within Strathspey shows that deglaciation proceeded rapidly after ca. 15 kyr BP. Critically this study demonstrates that glaciers last occupied the valleys of the Cairngorms immediately prior to the Lateglacial Interstadial (Bølling/Alleröd), contrary to previous assumptions that the last large‐scale glaciation of the massif took place in the Loch Lomond Stadial (Younger Dryas). This later event in the Cairngorms was therefore confined to the high corries. Copyright © 2005 John Wiley & Sons, Ltd.
Online trace enrichment to determine pyrethroids in river water by HPLC with column switching and photochemical induced fluorescence detection
Authors: Martínez Galera Maria , Barranco Martínez Dolores , Parrilla Vázquez Piedad , Gil García Maria Dolores
Published: October 2005

The potential of online trace enrichment on a highly apolar short column in LC was evaluated for the determination of pyrethroids in river water. Twelve millilitres of water samples, modified with 8 mL ACN (ACN/water 40 : 60, v/v), were passed through 50×4.6 mm ID first separation column packed with 5 μm Hypersil Elite C18. Pesticides were preconcentrated in this column while the matrix background was eluted to waste. Separation of pesticides was performed on a 3.5 μm symmetric C18 column (250×4.6 mm ID) with an ACN step gradient as mobile phase and fluorescence detection was used after postcolumn derivatization by using UV light. The use of photochemically induced fluorescence for detection improved sensitivity and selectivity. Quantification limits ranged from 0.05 to 0.1 μg/L and pesticide recoveries at two concentration levels (0.1 and 0.5 μg/L) were between 93.1 and 118.6%, with RSD between 2.5 and 7.5% (n = 3) in river water samples. No matrix effect was detected.
Rise of the sub-Doppler spectroscopy resolution in thin gas
cells by the spatial separation of pumping and probe radiations
Authors: Izmailov A Ch
Published: October 2005

The present theoretical work shows the possible
essential rise of the resolution of the well tested sub-Doppler
laser spectroscopy method, based on the optical pumping and
transit of atoms (molecules) in a thin gas cell, by means of the
definite spatial separation of pumping and probe light beams.
Process Optimization and Empirical Modeling for Electrospun Poly(D,L‐lactide) Fibers using Response Surface Methodology
Authors: Gu Shu‐Ying , Ren Jie
Published: October 2005

Summary: Ultrafine fibers were spun from poly(D,L‐lactide) (PDLA) solution using a homemade electrospinning set‐up. Fibers with diameter ranging from 350 to 1 900 nm were obtained. Morphologies of fibers and distribution of fiber diameters were investigated varying concentration and applied voltage by scanning electron microscopy (SEM). Average fiber diameter and distribution were determined from about 100 measurements of the random fibers with an image analyzer (SemAfore 5.0, JEOL). A more systematic understanding of process parameters of the electrospinning was obtained and a quantitative relationship between electrospinning parameters and average fiber diameter was established by response surface methodology (RSM). It was concluded that the concentration of polymer solution played an important role in the diameter of fibers and standard deviation of fiber diameter. Lower concentration tended to facilitate the formation of bead‐on‐string structures. Fiber diameter tended to increase with polymer concentration and decrease with applied voltage. Fibers with lower variation in diameter can be obtained at lower concentration regardless of applied voltage. Fibers with uniform diameter and lower variation in diameter can be obtained at higher concentration and higher applied voltage. Process conditions for electrospinning of PDLA could be chosen according to the model in this study.

Contour plots of average fiber diameter as a function of concentration and applied voltage.

image

Contour plots of average fiber diameter as a function of concentration and applied voltage.
Parkinson's disease and LRRK2: Frequency of a common mutation in U.S. movement disorder clinics
Authors: Kay Denise M. , Zabetian Cyrus P. , Factor Stewart A. , Nutt John G. , Samii Ali , Griffith Alida , Bird Tom D. , Kramer Patricia , Higgins Donald S. , Payami Haydeh
Published: October 2005

The G2019S mutation in the LRRK2 gene is reportedly a common cause of familial Parkinson's disease (PD) and may also have a significant role in nonfamilial PD. The objective of this study was to assess mutation carrier frequency in PD patients from movement disorder clinics in the United States, stratified by family history, age at onset, and geography; to determine carrier frequency in a large and well‐characterized control population; to examine segregation of mutation in families of patients; and to correlate genotype with clinical phenotype. One thousand four hundred twenty‐five unrelated PD patients from movement disorder clinics in Oregon, Washington, and New York and 1,647 unrelated controls were studied. The G2019S mutation was detected using a TaqMan assay and verified by sequencing. Eighteen of 1,425 patients and one of 1,647 controls had the mutation. Carrier frequency (± 2SE) in patients was 0.013 ± 0.006 overall, 0.030 ± 0.019 in familial PD, 0.007 ± 0.005 in nonfamilial PD, 0.016 ± 0.013 in early‐onset PD, and 0.012 ± 0.007 in late‐onset PD. Geographic differences were insignificant. Age at onset of mutation carriers ranged from 28 to 71 years. Mutation carriers were clinically indistinguishable from idiopathic PD. LRRK2 G2019S is the single most common pathogenic mutation linked to neurodegenerative disease to date. © 2005 Movement Disorder Society
B0 and B1‐insensitive uniform T1‐weighting for quantitative, first‐pass myocardial perfusion magnetic resonance imaging
Authors: Kim Daniel , Cernicanu Alexandru , Axel Leon
Published: October 2005

Myocardial perfusion can be estimated, in principle, from first‐pass MR images by converting the T1‐weighted signal–time curves to contrast agent concentration–time curves. Typically, T1 weighting is achieved by saturating the magnetization with a nonselective radiofrequency (RF) pulse prior to the imaging sequence. The accuracy of the perfusion estimate derived from the single‐point T1‐weighted signal depends on the initial residual longitudinal magnetization (RLM) produced by the saturation pulse. In this study we demonstrate that single‐shot, echo‐planar imaging can be used to show initial RLM resulting from incomplete saturation due to static magnetic field and RF field inhomogeneities in the heart at 1.5 T. Three saturation pulses, single, composite simple, and composite B1‐insensitive rotation (BIR‐4) were evaluated in phantom and cardiac experiments. The RLM image was calculated by normalizing the saturated image by a proton‐density‐weighted image. Mean RLM produced by the three saturation pulses was significantly different in noncontrast cardiac imaging (RLMsingle = 0.108 ± 0.078; RLMcomposite = 0.051 ± 0.052; RLMBIR‐4 = 0.011 ± 0.009; P < 0.001; n = 20). Using a BIR‐4 pulse to perform saturation of magnetization seems promising for improving the effectiveness and uniformity of T1 weighting for first‐pass perfusion imaging. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Parallel magnetic resonance imaging using the GRAPPA operator formalism
Authors: Griswold Mark A. , Blaimer Martin , Breuer Felix , Heidemann Robin M. , Mueller Matthias , Jakob Peter M.
Published: October 2005

In this article it is shown that GRAPPA reconstruction can be reformulated as a matrix operator, similar to ladder or propagator operators used in quantum mechanics, that shifts data in k‐space. Using this formalism, it is shown that there exists an infinitesimal GRAPPA operator that shifts data in k‐space by arbitrarily small amounts. Other desired k‐space shifts can then be accomplished through repeated applications of this infinitesimal GRAPPA operator. Implications of these ideas are described. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Analysis, design and optimization of structures using force method and genetic algorithm
Authors: Kaveh A. , Rahami H.
Published: October 2005

In the first part of this paper, the energy formulation of the force method is presented and analysis is performed using genetic algorithm. Two simple examples are provided to show the accuracy of the approach. In the second part, an efficient method is developed for designing structures with prescribed stress ratios for its members. The genetic algorithm performed very well and designs with specified stress ratios were achieved with a good convergence rate. A unit value of ci for all the members of a structure corresponds to the well known fully stressed design. In the third part, minimum weight design is formulated by the additional conditions being imposed on the design process. Again, genetic algorithm showed to be a powerful means for optimization. Copyright © 2005 John Wiley & Sons, Ltd.
Consumers' search behaviour for GM food information
Authors: Gao Ge , Veeman Michele , Adamowicz Wiktor
Published: October 2005

We report on the search for information on a genetically modified food by a sample of Canadian consumers. In the course of a computer‐based survey on consumer choices, some 445 respondents, drawn from a large representative panel of Canadian consumers, had the opportunity for voluntary access to information related to a genetically modified food through hyperlinks. Slightly less than half actually sought the information. The economic construct of benefit–cost reasoning was applied to assess possible reasons for the different patterns of information access seen in the study. Gender, employment status, rural or urban residency and the number of children in the household affected the probability that respondents would access information.

Copyright © 2005 John Wiley & Sons, Ltd.
The contaminated risk of GM crops: nationalism and the genetic modification debate
Authors: Hughes Emma
Published: October 2005

This paper examines the UK press coverage of genetically modified crops within the EU and explores how the theme of nationalism is utilized within the genetic modification (GM) debate. The way in which the EU is represented shifts, depending on whether it is being described in relation to the UK or the rest of the world (usually the USA). The EU is placed either as a threat to the UK, forcing genetically modified organisms into the country, or as a barrier, protecting UK citizens from the corrupt forces of the USA. This paper focuses on how countries and continents are constructed as being free of genetically modified organisms and how notions of nationalism and purity are used to achieve this. It argues that the way in which genetic modification is discussed often leads to an inherent but unintended xenophobic discourse. It is not just the mixing of genes that we are told to fear; the mixing of peoples is also alluded to. This paper explores the ways in which risks can be merged, as genetic modification specifically becomes linked to the asylum debate. Finally, the paper will discuss the dangers of contaminating the genetic modification debate with xenophobic arguments.

Copyright © 2005 John Wiley & Sons, Ltd.
The GM foods debate in Europe: history, regulatory solutions, and consumer response research
Authors: Scholderer Joachim
Published: October 2005

The debate on genetically modified (GM) foods has been led on multiple levels in Europe, including such diverse frames of reference as economic policy and international trade, environmental risk, bioethics, consumer protection and food safety. The shifting frames of reference are traced over the past three decades, focusing on events leading up to the five‐year quasi‐moratorium on GM foods and its final lifting in 2004. While regulatory problems have been resolved, commercial actors in the food chain have done little to prepare themselves for the actual marketing of GM foods to European consumers. Relevant consumer research is reviewed, and a potential way forward for commercial actors is outlined. It is concluded that the conceptualization of GM foods should be turned back on its feet, understanding them as foods and not just as embodiments of technology.

Copyright © 2005 John Wiley & Sons, Ltd.
Implementing the Cartagena Biosafety Protocol through national biosafety regulatory systems: an analysis of key unresolved issues
Authors: Jaffe Gregory
Published: October 2005

The Cartagena Biosafety Protocol is the primary driving force behind countries establishing national biosafety regulatory systems for genetically engineered crops and animals. That international agreement attempts to set forth the scientific and legal boundaries for those systems, and establish a minimum set of rules and procedures. This paper analyses whether the Protocol will achieve a degree of legal certainty in the field of biosafety regulations and some level of global harmonization. The paper concludes that, while the Protocol is a good model for certain portions of a national biosafety regulatory system, it provides little guidance on several issues key to biosafety regulation. The Protocol gives discretion to individual countries to decide on what the applicable safety standard should be, how to incorporate socioeconomic considerations, how to address food safety and how to incorporate public participation. The resolution of these four issues by each country could have a far greater influence than the Protocol itself on the nature of their national biosafety regulatory system.

Copyright © 2005 John Wiley & Sons, Ltd.
Communication dimensions of the UK foot and mouth disease crisis, 2001
Authors: Gregory Anne
Published: October 2005

The foot and mouth disease outbreak which started in February 2001 in the UK was the most severe civil crisis that had been seen in the UK since the Second World War. The crisis has been the subject of numerous reports, but this paper examines the communication dimensions of the outbreak, in particular the work of the Communications Directorate of the lead Government department, the Ministry of Agriculture, Fisheries and Food (now the Department of the Environment, Food and Rural Affairs). Within the context of the Crisis literature, this paper discusses:

the main communication activities that were undertaken;

key issues;

lessons that have been learned and applied by the Department of the Environment, Food and Rural Affairs.

Finally it provides an analysis of some of the main communication issues, concluding with a checklist that should be borne in mind for future large‐scale civil crises.

Copyright © 2005 John Wiley & Sons, Ltd.
Differential detection of S100A8 in transitional cell carcinoma of the bladder by pair wise tissue proteomic and immunohistochemical analysis
Authors: Tolson Jonathan P. , Flad Thomas , Gnau Volker , Dihazi Hassan , Hennenlotter Joerg , Beck Alexander , Mueller Gerhard A. , Kuczyk Markus , Mueller Claudia A.
Published: October 2005

The search for novel molecular markers of tumor invasion is vital if strategies are to become more effective in the diagnostic and prognostic management of transitional cell carcinoma of the bladder. Up to 50% of tumors detected at stage 1 (pT1) progress to a higher grade even after endoscopic surgical resection, and there are currently no protein markers of this aggressive, invasive phenotype. We have combined SELDI‐TOF‐MS, ClinProt magnetic bead enrichment, Nano‐LC‐ESI‐ion trap tandem mass spectrometry and immunohistochemical analysis to the study of 12 invasive bladder cancer tissue biopsies paired with normal bladder tissue samples obtained from the same patients for the definition and identification of proteins up‐regulated in the tumors. We report the inflammation‐associated calcium binding protein S100A8 (MRP‐8, calgranulin A) to be highly expressed in tumor cells in contrast to normal urothelium in 50% of the samples, as well as two unidentified protein markers at 5.75 and 6.89 kDa that were differentially detected in 9/12 and 10/12 tumor samples, respectively. These new markers, when fully characterized, may contribute to new target proteins for the prediction of aggressive, invasive bladder tumors.
Ethylene/α‐olefin copolymerization with bis(β‐enaminoketonato) titanium complexes activated with modified methylaluminoxane
Authors: Tang Li‐Ming , Hu Tao , Pan Li , Li Yue‐Sheng
Published: October 2005

Copolymerizations of ethylene with α‐olefins (i.e., 1‐hexene, 1‐octene, allylbenzene, and 4‐phenyl‐1‐butene) using the bis(β‐enaminoketonato) titanium complexes [(Ph)NC(R2)CHC(R1)O]2TiCl2 (1a: R1 = CF3, R2 = CH3; 1b: R1 = Ph, R2 = CF3; and 1c: R1 = t‐Bu, R2 = CF3), activated with modified methylaluminoxane as a cocatalyst, have been investigated. The catalyst activity, comonomer incorporation, and molecular weight, and molecular weight distribution of the polymers produced can be controlled over a wide range by the variation of the catalyst structure, α‐olefin, and reaction parameters such as the comonomer feed concentration. The substituents R1 and R2 of the ligands affect considerably both the catalyst activity and comonomer incorporation. Precatalyst 1a exhibits high catalytic activity and produces high‐molecular‐weight copolymers with high α‐olefin insertion. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6323–6330, 2005
Linear shear viscoelasticity of confined, end‐attached polymers in a near‐theta solvent
Authors: Dai Lenore L. , Granick Steve
Published: October 2005

Diblock copolymers of polystyrene and polyvinylpyridine, end‐attached to mica by the traditional method of selecting one block to be insoluble and the other block to be soluble in the solvent, were studied with surface‐force experiments while immersed in trans‐decalin, a near‐theta solvent for the polystyrene block, with special attention given to the small‐amplitude shear viscoelastic response. The relaxation time, defined as the inverse frequency at which the effective loss modulus equaled the effective storage modulus, was studied not only as a function of the film thickness but also as a function of the grafting density. The relaxation times started to slow in direct proportion to diminishing surface separation when the surface separation took the value D ≈ Lo/3 (where Lo is the thickness of the uncompressed end‐attached layer). Attempts to make comparisons with available theories met with limited success. To test experimentally the origin of this shear viscoelastic slowdown, similar measurements were made with adsorbed polystyrene with a molecular weight similar to that of the polystyrene moiety of the diblock copolymer, and it was found that high magnitudes of the effective viscoelastic shear moduli appeared only when the compression was much larger. In a control experiment in which interpenetration between opposed end‐attached chains was precluded, we also studied the case of adsorbed polystyrene–polyvinylpyridine on one side and a bare mica surface on the other side, and the effective viscoelastic shear forces were reduced by nearly 1 order of magnitude. By inference, in the opposed diblock copolymer systems, we attributed the slowdown of the relaxation times with decreasing film thickness to the interpenetration of end‐attached chains. Additional comments are made regarding the ratio of shear forces to compressive forces, which is called the small‐strain friction coefficient. This is believed to be the first quantification of the linear‐response relaxation time of end‐attached polymer layers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3487–3496, 2005
Correspondence of function and phylogeny of ABC proteins based on an automated analysis of 20 model protein data sets
Authors: Fuellen Georg , Spitzer Michael , Cullen Paul , Lorkowski Stefan
Published: October 2005

Using our BLAST‐based procedure RiPE (Retrieval‐induced Phylogeny Environment), which automates the evolutionary analysis of a protein family, we assembled a set of 1138 ABC protein components [adenosine triphosphate (ATP)‐binding cassette and transmembrane domain] from the protein data sets of 20 model organisms and subjected them to phylogenetic and functional analysis. For maximum speed, we based the alignment directly on a homology search with a profile of all known human ABC proteins and used neighbor‐joining tree estimation. All but 11 sequences from Homo sapiens, Arabidopsis thaliana, Drosophila melanogaster, and Saccharomyces cerevisiae were placed into the correct subtree/subfamily, reproducing published classifications of the individual organisms. By following a simple “function transfer rule”, our comparative phylogenetic analysis successfully predicted the known function of human ABC proteins in 19 of 22 cases. Three functional predictions did not correspond, and 10 were novel. Predictions based on BLAST alone were inferior in five cases and superior in two. Bacterial sequences were placed close to the root of most subtrees. This placement coincides with domain architecture, suggesting an early diversification of the ABC family before the kingdoms split apart. Our approach can, in principle, be used to annotate any protein family of any organism included in the study. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Structural differences between allelic variants of the ovine prion protein revealed by molecular dynamics simulations
Authors: Bujdoso Raymond , Burke David F. , Thackray Alana M.
Published: October 2005

We have modeled ovine prion protein (residues 119–233) based on NMR structures of PrP from other mammalian species. Modeling of the C‐terminal domain of ovine PrP predicts three helices: helix‐1 (residues 147–155), flanked by two short β‐strands; helix‐2 (residues 176–197), and helix‐3 (residues 203–229). Molecular dynamics simulations on this model of ovine PrP have determined structural differences between allelic variants. At neutral pH, limited root mean‐squared (RMS) fluctuations were seen in the region of helix‐1; between β‐strand‐2 and residue 171, and the loop connecting helix‐2 and helix‐3. At low pH, these RMS fluctuations increased and showed allelic variation. The extent of RMS fluctuation between β‐strand 2 and residue 171 was ARR > ARQ > VRQ. This order was reversed for the loop region connecting helix‐2 and helix‐3. Although all three variants have the potential to display an extended helix at the C‐terminal region of helix‐1, the major influence of the VRQ allele was to restrict the conformations of the Asn162 and Arg139 side‐chains. Variations observed in the simulations in the vicinity of helix‐1 correlated with reactivity of C‐terminal specific anti‐PrP monoclonal antibodies with peripheral blood cells from scrapie‐susceptible and ‐resistant genotypes of sheep: cells from VRQ homozygous sheep showed uniform reactivity, while cells from ARQ and ARR homozygous sheep showed variable binding. Our data show that molecular dynamics simulations can be used to determine structural differences between allelic variants of ovine PrP. The binding of anti‐PrP monoclonal antibodies to ovine blood cells may validate these structural predictions. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Analysis of three different types of fullerene derivatives by laser desorption/ionization time‐of‐flight mass spectrometry with new matrices
Authors: Zhou Lihua , Deng Huimin , Deng Qinying , Zheng Liping , Cao Yong
Published: October 2005

Three different types of fullerene derivatives, namely methano[60]fullerene dicarboxylate esters, [60]fulleropyrrolidines, and imino[60]fullerenes, were analyzed by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry using trans‐4‐tert‐butyl‐4′‐nitrostilbene (TBNS), 1,8,9‐anthracenetriol (dithranol), 6‐aza‐2‐thiothymine (ATT), 2,5‐dihydroxybenzoic acid (DHB) and carbazole as matrices. Unit mass resolution (sufficient to clearly resolve isotopic peaks), high signal‐to‐noise ratio, and clean mass spectra for all analytes were acquired by the optimization of experimental parameters and choice of optimal solvent for the matrix and molar matrix‐to‐analyte ratio. The new matrix, TBNS, gave the best results in the positive‐ion mode, as it can provide higher yields of analyte molecular ions at a lower laser threshold than the other four matrices, together with a very low degree of unwanted fragmentations. In the negative‐ion mode dithranol was better than TBNS, and the other three matrices gave relatively poor mass spectra for these fullerene derivatives. Copyright © 2005 John Wiley & Sons, Ltd.
Multiple hypothesis testing strategies for genetic case–control association studies
Authors: Rosenberg Philip S. , Che Anney , Chen Bingshu E.
Published: October 2005

The genetic case–control association study of unrelated subjects is a leading method to identify single nucleotide polymorphisms (SNPs) and SNP haplotypes that modulate the risk of complex diseases. Association studies often genotype several SNPs in a number of candidate genes; we propose a two‐stage approach to address the inherent statistical multiple comparisons problem. In the first stage, each gene's association with disease is summarized by a single p‐value that controls a familywise error rate. In the second stage, summary p‐values are adjusted for multiplicity using a false discovery rate (FDR) controlling procedure. For the first stage, we consider marginal and joint tests of SNPs and haplotypes within genes, and we construct an omnibus test that combines SNP and haplotype analysis. Simulation studies show that when disease susceptibility is conferred by a SNP, and all common SNPs in a gene are genotyped, marginal analysis of SNPs using the Simes test has similar or higher power than marginal or joint haplotype analysis. Conversely, haplotype analysis can be more powerful when disease susceptibility is conferred by a haplotype. The omnibus test tracks the more powerful of the two approaches, which is generally unknown. Multiple testing balances the desire for statistical power against the implicit costs of false positive results, which up to now appear to be common in the literature. Published in 2005 by John Wiley & Sons, Ltd.
The amniotic sheet: a truly benign condition?
Authors: Tan K. B. L. , Tan T. Y. T. , Tan J. V. K. , Yan Y. L. , Yeo G. S. H.
Published: October 2005

Objective

Amniotic sheets are the result of uterine synechiae that have been encompassed by the expanding chorion and amnion. Radiologically they are seen as ‘shelves’ in the amniotic cavity. The benign nature of such amniotic sheets has been documented in many case series in the literature. The objective of this study was to determine the characteristics (if any) of amniotic sheets that predict fetal outcome.

Methods

Between January 2001 and December 2002, detailed scans were performed in 30 476 singleton pregnancies at 18–32 weeks' gestation. Of these, 44 cases of amniotic sheets were detected. The characteristics studied were site of amniotic sheet and whether the amniotic sheet was complete (i.e. no free edge seen on ultrasound) or incomplete (i.e. presence of free edge seen on ultrasound). The primary fetal outcome studied was stillbirth.

Results

The incidence of amniotic sheets was 0.14%. Two were complete and 42 were incomplete. Of the 38 cases with known outcomes there were two intrauterine deaths. There was no association between fetal outcome and the uterine location of the amniotic sheet (i.e. upper two‐thirds vs. lower third, P = 0.5). There was, however, an association between the completeness of the amniotic sheets and intrauterine death (P = 0.002). Both instances of intrauterine death occurred in the two cases with complete amniotic sheets. Postmortem examination suggested that cord accidents were the cause of intrauterine death in both cases.

Conclusions

This study supports the view that incomplete amniotic sheets are benign. It also suggests for the first time that complete amniotic sheets may be associated with intrauterine death. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Fetal cardiac contractility before and after intrauterine transfusion
Authors: Sikkel E. , Klumper F. J. C. M. , Oepkes D. , Teunissen A. K. K. , Meerman R. H. , Le Cessie S. , Kanhai H. H. H. , Vandenbussche F. P. H. A.
Published: October 2005

Objective

To evaluate the effect of fetal anemia and intrauterine transfusion on ventricular shortening fraction.

Methods

The end‐diastolic and end‐systolic transverse dimensions of the left and right ventricles were obtained using M‐mode ultrasonography. The shortening fractions of both ventricles were calculated at three time points: before, immediately after and one day after intrauterine transfusion. The blood volume given at intrauterine transfusion was expressed as a percentage of estimated fetoplacental blood volume.

Results

Complete measurements were obtained from 49 transfusions in 23 fetuses. Intrauterine transfusion was performed at a median gestational age of 31 (range, 19–35) weeks. Median hemoglobin concentration before and after intrauterine transfusion was 7.9 (range, 2.7–13.7) g/dL and 14.3 (range, 12.7–16.1) g/dL, respectively. Both left and right ventricular shortening fractions differed significantly between the three time points. Left ventricular shortening fraction decreased immediately after transfusion in 43 (88%) of the 49 procedures. Right ventricular shortening fraction decreased immediately after transfusion in 42 (86%) of the 49 procedures. At the first intrauterine transfusion, there was only a weak correlation between the decrease in shortening fraction of both ventricles and the transfused volume (left: R2 = 0.15; P = 0.20/right: R2 = 0.005; P = 0.81).

Conclusion

Transfusion significantly decreases the shortening fraction of both ventricles of the fetal heart. There is, however, little correlation between the decrease in shortening fraction and the volume of red cells given at intrauterine transfusion. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Z‐velocity in screening for intrauterine growth restriction
Authors: Mondry A. , Pengbo L. , Loh M. , Mongelli M.
Published: October 2005

Objectives

Ultrasound scans provide the basis for detection of intrauterine growth restriction (IUGR) but often fail to distinguish IUGR from small‐for‐gestational age (SGA) fetuses. This study introduces the concept of Z‐velocity, calculated as changes in Z‐scores over time, as an additional criterion in the diagnosis of IUGR.

Methods

A computer program simulated 50 000 fetal abdominal circumference (FAC) scans based on published growth formulae. False‐positive rates were calculated to determine optimal scan time and scan intervals. Using an independent simulation of 32 500 FAC scans, the two methods were compared using receiver–operating characteristics (ROC) curve analysis.

Results

ROC showed areas under the curve of > 0.74 over the complete range of scan intervals. The positive predictive value of growth arrest as the only diagnostic criterion was, however, too low to recommend it as an exclusive or the first diagnostic criterion.

Conclusions

Z‐velocity can be used to decide whether further investigations for growth abnormality are required in fetuses that fall below the 10th percentile. The gain of combined diagnostic approaches should be calculated from large databases that include the neonatal ponderal index as the gold standard. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
The use of high resolution magnetic resonance imaging in the prenatal diagnosis of fetal nuchal tumors
Authors: Knox E. M. , Muamar B. , Thompson P. J. , Lander A. , Chapman S. , Kilby M. D.
Published: October 2005

Fetal magnetic resonance imaging (fetal MRI) is an important adjunct to antenatal imaging especially when neonatal surgery is contemplated. We report two cases of fetal nuchal tumors, which were diagnosed incidentally on an ultrasound scan and had fetal MRI to aid diagnosis, prognosis, counseling and management planning. In the first case, fetal MRI aided diagnosis and prenatal multidisciplinary management of a cervical teratoma. Tracheal involvement could not be excluded and an ex‐utero intrapartum treatment procedure was planned. Postnatal MRI and angiography provided further information prior to surgery. In the second case, fetal MRI assisted thorough counseling following the finding of a cervical lesion thought to be a cervical teratodermoid, a multicystic hygroma or congenital lymphectasia. The parents opted for termination of the pregnancy. Postmortem findings confirmed the extent of involvement of surrounding structures diagnosed prenatally. The mass was found to be a hamartomatous hemangiolymphangioma. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Ultrasound features of different histopathological subtypes of borderline ovarian tumors
Authors: Fruscella E. , Testa A. C. , Ferrandina G. , De Smet F. , Van Holsbeke C. , Scambia G. , Zannoni G. F. , Ludovisi M. , Achten R. , Amant F. , Vergote I. , Timmerman D.
Published: October 2005

Objective

To describe the gray‐scale sonographic and color Doppler imaging features of the most common histopathological subtypes of borderline ovarian tumors.

Methods

We analyzed retrospectively the preoperative transvaginal sonographic reports of patients with a histological diagnosis of borderline ovarian tumor. All patients were scanned consecutively by two of the investigators using transabdominal and transvaginal gray‐scale imaging to assess the morphology and color Doppler to obtain indices of the blood flow. Sonographic findings were compared to histopathological data.

Results

A total of 113 consecutive cases were reviewed from two referral centers for gynecological oncology. At histological examination 50 tumors (44%) were classified as being serous borderline ovarian tumors (SBOT), 61 (54%) were mucinous borderline ovarian tumors (MBOT) (42 intestinal type and 19 endocervical type), and two patients (2%) presented with borderline endometrioid tumors. SBOTs and endocervical‐type MBOTs had very similar sonographic features and a smaller diameter, fewer locules (usually unilocular‐solid lesions) and a higher color score than intestinal‐type MBOTs. Intestinal‐type MBOTs were characterized by a significantly higher percentage of lesions with > 10 locules when compared with the endocervical‐type MBOTs.

Conclusion

Intestinal‐type MBOTs have different sonographic features from other common borderline ovarian tumors. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Four‐dimensional ultrasound guidance of prenatal invasive procedures
Authors: Kim S. R. , Won H. S. , Lee P. R. , Kim A.
Published: October 2005

Objective

Technological advances in ultrasonography have revolutionized prenatal diagnosis and treatment. Here we evaluate the effectiveness of using four‐dimensional (4D) ultrasonography to guide prenatal invasive procedures.

Patients and methods

Prenatal invasive procedures using 4D ultrasound were recorded prospectively in 93 cases: 10 amnioinfusions, 50 amniocenteses, 8 chorionic villus samplings (CVS) and 25 cordocenteses. The needle target site was first identified using the two‐dimensional (2D) mode, and was then confirmed using the three‐dimensional (3D) mode. The needle was inserted under 4D ultrasound guidance. After selecting the needle target site, the true position of the needle was determined in three planes (‘real‐time 3D targeting’).

Results

Using 4D ultrasound guidance, most procedures were performed within 5 min and with a 100% success rate, even in cases involving severe oligohydramnios (amniocentesis), thin placentas (CVS) or narrow umbilical veins (cordocentesis). Moreover, there were no serious complications during or after any procedure.

Conclusions

4D ultrasonography can be used to guide various prenatal invasive procedures offering clear information in all three planes. It is likely that such imaging will reduce the time taken to complete the procedures and reduce the risks associated with them. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.