bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal Collocated and Multivariable Hybrid Active-Passive Vibration Control Design
Authors: Kemp Jonathan D. , Clark Robert L.
Published: October 2004

Hybrid control measures are optimized for collocated and multivariable attenuation of vibratory energy in a typical aircraft panel. Design techniques first optimize collocated hybrid controllers combining active and passive technology on the same footprint. These techniques are then extended to multivariable hybrid controllers containing at least two pairs of actuators and sensors in addition to passive damping. An optimization routine based on an energy-balancing cost metric selects active and passive control elements to minimize both the broadband vibratory energy of the structure and the weight, volume, and energy use of the control system. Further, optimization of inherent energy exchanges within the hybrid controller allows more aggressive, targeted, active control with minimal passive damping treatment. Optimization reveals idealized placements, sizes, and orientations of active and passive control elements. Active piezoceramic patches partner with passive constrained-layer damping treatment to extend and demonstrate the potential of optimal hybrid vibration control.
Performance of a Magnetorheological Hydraulic Power Actuation System
Authors: Yoo Jin-Hyeong , Wereley Norman M.
Published: October 2004

The performance of a magnetorheological (MR) hydraulic power system is analytically and experimentally assessed. Four MR valves are implemented as a Wheatstone bridge hydraulic power circuit to drive a hydraulic actuator using a gear pump. The compact hydraulic power actuation system is a Wheatstone bridge network driving a conventional hydraulic actuator. A key advantage of using MR valves in hydraulic actuation systems is that the valves have no moving parts. This reduces complexity and enhances durability compared to conventional mechanical valves. In such a system, an MR fluid is used as the hydraulic fluid. A constant volume pump is used to pressurize the MR fluid. If a change in direction is required, the flow through each of the valves in the Wheatstone bridge can be controlled smoothly via changing the applied magnetic field. A magnetic field analysis is conducted to design a high-efficiency compact MR valve. The behavior and performance of the MR valve is expressed in terms of nondimensional parameters. The performance of the hydraulic actuator system with a Wheatstone bridge network of MR valves is derived using three different constitutive models of the MR fluid: an idealized model (infinite yield stress), a Bingham plastic model, and a biviscous model. The analytical system efficiency in each case is compared to experiment, and departures from ideal behavior, that is, a valve with infinite blocking pressure, are recognized.
On-line Imitative Interaction with a Humanoid Robot Using a Dynamic Neural Network Model of a Mirror System
Authors: Ito Masato , Tani Jun
Published: October 2004

This study presents experiments on the imitative interactions between a small humanoid robot and a user. A dynamic neural network model of a mirror system was implemented in a humanoid robot, based on the recurrent neural network model with parametric bias (RNNPB). The experiments showed that after the robot learns multiple cyclic movement patterns as embedded in the RNNPB, it can regenerate each pattern synchronously with the movements of a human who is demonstrating the corresponding movement pattern in front of the robot. Further, the robot exhibits diverse interactive responses when the user demonstrates novel cyclic movement patterns. Those responses were analyzed and categorized. We propose that the dynamics of coherence and incoherence between the robot’s and the user’s movements could enhance close interactions between them, and that they could also explain the essential psychological mechanism of joint attention.
Learning Invariant Sensorimotor Behaviors: A Developmental Approach to Imitation Mechanisms
Authors: Andry Pierre , Gaussier Philippe , Nadel Jacqueline , Hirsbrunner Beat
Published: October 2004

This paper examines the interest of a developmental approach applied to the design of autonomous robots and the understanding of adaptive behaviors, such as imitation. The proposed model is a neural network architecture that learns and uses associations between vision and arm movements, even if the problem is ill posed (in the case of mapping problems between the visual space and the joints space of the arm). The central part of the model is a visuo-motor map able to represent the arm end point’s position in an ego-centered space (constrained by the vision) according to motor information (the proprioception). Sensorimotor behaviors such as tracking, pointing, spontaneous imitating, and sequences learning can then be obtained as the consequence of different internal dynamics computed on neural fields triggered by the visuo-motor map. The readout mechanism also explains how an apparently complex behavior can be generated and controlled from one simple internal dynamics and how at the same time the learning problems can be simplified. While highlighting the generic aspect of our model, we show that our robot can autonomously imitate and learn more complex sequences of gestures after the online learning of the visual and proprioceptive control of its hand extremity. Finally, we defend the idea of a co-development of imitative and sensorimotor capabilities, allowing the acquisition and the building of increasingly complex behavioral capabilities.
The educational principles of social education and special education for children and youngsters in care
Authors: Bryderup Inge M.
Published: October 2004

This article presents results from a Danish quantitative and qualitative study of social education and special education in residential care centres, private residential care centres and day-care centres. Among other aspects this concerned the educational approach of the institutions as well as their organizational affiliation and size, the organization and planning of special educational provisions, descriptions and analyses of the educational processes and the organization of special educational provisions and social intervention. The study furthermore aimed at generating knowledge about the correlation between special education and social education, understandings of the concept of education, the organization and contents of special education and cooperation with external partners. The article offers analyses of two central tendencies: compensatory thinking, meaning an educational approach addressing the ‘problems’ and troubled backgrounds of the children and youngsters in care; and comprehensive thinking, referring to a unification of social education and special educational provisions. In conclusion the author suggests alternative views on and ways of approaching working with children and youngsters in care.
Challenging the sports-industrial complex: human sciences, advocacy and service
Authors: Maguire Joseph
Published: October 2004

This article is an attempt to provide an alternative view of sports science and future sport worlds. For reasons to do with fundamental science, involved advocacy and committed service, and in a period of intensified globalization, it is necessary to reconfigure the nature and scope of teaching and research within the subdiscipline of sports sciences. However, just as the military-industrial complex dominates aspects of broader global processes, and of the academy in particular, advocates of the sports-industrial complex may well seek to thwart such alternative possibilities. As a result, the role of academics will be confined to the production of world and Olympic medals - sports scientists will be the technicians, and student-athletes the cogs, in the machine. In contrast to the performance efficiency ethos, a human development model is advocated.
Locating Sexualities: From Here to Normality
Authors: Richardson Diane
Published: October 2004

Lesbian and gay movements are increasingly demanding equal rights of citizenship on the grounds of being the ‘same’ as most heterosexuals. Citizenship is the central concept appealed to in calls for inclusion, and it is through claims to normalcy that social integration is justified. Moreover, it would appear that access to this new citizenship status is located primarily through being in a publicly recognized normative (good gay) couple relationship. This integration of lesbians and gay men into social and political life as ‘normal citizens’ represents a significant shift with important implications for (a) understandings of sexual citizenship, (b) the meanings and importance attached to sexual identities and (c) the public/private binary. This article will develop and extend previous theoretical work on sexuality and citizenship by considering these issues.
Queer Theory, Butch/Femme Identities and Lesbian Space
Authors: Eves Alison
Published: October 2004

Queer theory has been criticized for its textual focus and lack of attention to the structural and to everyday social practices. This article is part of a wider attempt to draw on the different strengths and insights of queer theory and qualitative social sciences. I identify areas of intersection between them which suggest potential ways of developing a queer sociology. The article considers the negotiation of gender and sexual identity categories at the level of individual butch and femme identity narratives. The concept of interpretative repertoires is used to theorize the ways in which lesbians are both positioned by and actively negotiate particular discourses. I am interested in the spatial aspects of the negotiation and contestation of identities and the article examines the ways in which particular interpretative repertoires produce butch and femme metaphorical and material spaces. The article draws on a concept of space as fluid, contested in meaning and created through social interactions. The achievement of lesbian visibility is examined as a strategic intervention in the establishment of subcultural space in which lesbian genders may be performed and read in specifically lesbian ways. Butch and femme aesthetics are examined as tactics in resisting heterosexual space and demanding lesbian presence.
Picturing America’s ‘War on Terrorism’ in Afghanistan and Iraq
Authors: Griffin Michael
Published: October 2004

Following research on depictions of the Persian Gulf War of 1991, this article discusses the nature of US news-magazine photo coverage of the ‘War on Terrorism’ in Afghanistan and the military invasion of Iraq. The analysis suggests that news-magazine photographs primarily serve established narrative themes within official discourse: that published photographs most often offer prompts for prevailing government versions of events and rarely contribute independent, new or unique visual information. Despite claims of ‘live’ and spontaneous coverage, photographs from Afghanistan and Iraq, like those from the Gulf War in 1991, are characterized by a narrow range of predictable, recurrent motifs. Repetitive images of the mustering and deployment of the American military arsenal overshadow any fuller or more complex range of depiction. And when dominant news narratives, such as the fall of the Taliban or the fall of Baghdad, come to a close, photographic coverage of continuing events in Afghanistan and Iraq falls off sharply.
Post-war Japan in photographs
Authors: Darling-Wolf Fabienne
Published: October 2004

Through a discourse analysis of news photographs published after the end of the Second World War, this study investigates how Japan’s new position as a defeated and occupied nation was visually negotiated in the two decades following the war in the pages of one major national Japanese English-language newspaper. It addresses, in particular, how symbolic representations of the Japanese nation were (re)defined and reinterpreted in these photographs in the aftermath of the war under the significant influence of occupation leaders eager to reorganize the Japanese press system following American models. It argues that visual representations of Japan and its leaders created shortly after the war illustrate the beginnings of a process of erasure of the past and cultural reinterpretation that scholars of the Japanese cultural environment have identified as a central component of Japanese contemporary (post)modern identity.
Against the grain
Authors: Nilsson Maria E.
Published: October 2004

During the fascist dictatorship (1939-75) in Spain, photojournalism was circumscribed by censorship, as were all other aspects of media and culture. In the early 1970s, however, in tandem with a growing opposition movement, pro-democracy journalists and periodicals sought to push the boundaries of censorship by giving voice and visibility to critics of the government. In this context, photography became a tool for denouncing and critiquing the regime. This article traces this shift by examining photographs of a pro-democracy demonstration held in Barcelona in February of 1976, three months after the death of dictator Francisco Franco. Drawing on personal interviews with photojournalists and analysis of photographs and publication context, the author analyzes photographic practices and the relationship between politics and aesthetics in photographs, and concludes that the examined photographs and practices during a period of censorship in Spain were effective tools for advocacy.
’About a Girl’
Authors: Hartley John , Rennie Ellie
Published: October 2004

Corinne’s friend Rose is sprawled on an old couch in Corinne’s flat in London. Surrounding Rose on the beer-stained carpet are a few mugs, an ashtray and a telephone cord. The photo is a record of Corinne Day’s reality from a time when she was still on the dole and partying hard. Her bleak but intimate photography became famous in the fashion pages of magazines like The Face and Vogue, where her early photographs of an unknown young model called Kate Moss created the visual style known as ‘dirty realism’ or ‘grunge’. As she describes it, ‘There we were struggling to pay the rent, living in a dump, surrounded by glamorous magazines that were so far away from our own level of living... Fashion magazines had been selling sex and glamour for far too long. I wanted to instill some reality into a world of fantasy’ (Cotton, 2000).

Concentrating on British photographer Corinne Day’s work, this article explores the interface between photojournalism and fashion. Day’s photographs are documents of contemporary life but destined for fashion pages. Beyond its ostensible purpose, contemporary fashion photography in magazines like Vogue can be seen to continue and extend the purposes of photojournalism in the documentary tradition. Furthermore, the compulsion towards art and aesthetics found in photojournalism since the days of Picture Post indicates that the same boundary has been pushed from the other side too, ever since photojournalism’s ascendance. This article therefore traces convergences among some aesthetic, discursive and institutional oppositions that have long been kept carefully separated: ‘reality’ and ‘fantasy’ worlds; national identity and art; journalism and fashion.
Self-reference, Mutual Identification and Affect
Authors: Chen Hon-Fai
Published: October 2004

In this article I argue that in Parsons’ later works there is an implicit alternative to his normative solution to the problem of order. Luhmann’s theory of self-reference and Pizzorno’s notion of mutual identification are firstly invoked to recast the Parsonsian problematic in a ‘post-normative’ light. On the basis of Parsons’ later theory of societal solidarity, ritual and myth, I propose further that his concept of symbolic communication of affect delineates the process through which individuals recognize each other and thereby constitute social order. Mediated with symbols that are grounded in the human condition, communication of affect may substitute institutionalization of value to be the condition of possibility of social order. I also demonstrate that the significance of affect is a theme shared by the Chinese tradition of Confucianism, which is introduced to refine the humanistic intent of Parsons’ theory and broaden its scope of applicability outside the Western context.
Florence Kelley
Authors: Timming Andrew R.
Published: October 2004

Florence Kelley is a seminal, yet largely unrecognized, figure in the history of sociology. The article examines her contributions to the discipline and presents a socio-historical outline of the formation of her sociological thought. It highlights four themes that are integral to Kelley’s praxis: women, workers, immigrants and children. Following a discussion of these themes, I go on to argue that Kelley has been neglected generally amongst many contemporary sociologists as a result of possible sexist and anti-Marxist tendencies within the discipline. Finally, I throw some light on the fact that even radical circles in contemporary sociology tend to exclude systematically their radical female counterparts.
An Anatomy of the Leicester School of Sociology
Authors: Rojek Chris
Published: October 2004

Eric Dunning studied under Elias and Neustadt and was appointed by the latter to lecture in sociology. He remained in Leicester throughout his academic career, eventually attaining a Chair in Sociology. He is a prominent figure in the sociology of sport and has lectured widely throughout the world. This interview sheds light on an important chapter in the development of British sociology and the unique working relationship between Elias and Neustadt. Remarkably, it is one of the first attempts to assess the Leicester tradition of sociological activity.
The myth of the risk-tolerant entrepreneur
Authors: Xu Hongwei , Ruef Martin
Published: October 2004

Entrepreneurs have long been assumed to be more risk-tolerant than the general population. In this article, we analyze the financial risk propensity of business founders using a unique, representative dataset of nascent entrepreneurs in the United States. We deploy two models of entrepreneurial behavior: a strategic model of risk tolerance, based on investment choices; and a non-strategic model of risk tolerance, based on information bias about business success. For both models, our empirical results consistently show that nascent entrepreneurs are more risk-averse than non-entrepreneurs. To reconcile the financial risk aversion of entrepreneurs with the high risk of financial loss among startups, we suggest that many of the motivations that individuals have for founding business ventures are non-pecuniary in nature.
Information or influence? The benefits of experience for managing political uncertainty
Authors: Henisz Witold J. , Delios Andrew
Published: October 2004

We examine the extent to which two sources of uncertainty over the future policy environment - political hazards and regime change - influence foreign-owned subsidiary exit rates. We find that prior exits by peer firms enhance exit rates, particularly when political hazards are high. We also find that a multinational firm’s own experience under the current political regime has a moderating influence on subsidiary exit rates in the presence of political hazards, but it enhances exit rates after a change in the political regime. These findings support the argument that in contrast to the informational benefit conferred by prior peer firms’ exits, own firm experience proxies for actual or perceived influence in a nation’s policy-making process.
Early postoperative hyperglycaemia is not a risk factor for infectious complications and prolonged in-hospital stay in patients undergoing oesophagectomy: a retrospective analysis of a prospective trial
Authors: Vriesendorp Titia M , DeVries JHans , Hulscher Jan BF , Holleman Frits , van Lanschot Jan J , Hoekstra Joost BL
Published: October 2004

Introduction

Treating hyperglycaemia in hospitalized patients has proven to be beneficial, particularly in those with obstructive vascular disease. In a cohort of patients undergoing resection for oesophageal carcinoma (a group of patients with severe surgical stress but a low prevalence of vascular disease), we investigated whether early postoperative hyperglycaemia is associated with increased incidence of infectious complications and prolonged in-hospital stay.

Methods

Postoperative glucose values up to 48 hours after surgery were retrieved for 151 patients with American Society of Anesthesiologists class I or II who had been previously included in a randomized trial conducted in a tertiary referral hospital. Multivariate regression analysis was used to define the independent contribution of possible risk factors selected by univariate analysis.

Results

In univariate regression analysis, postoperative glucose levels were associated with increased length of in-hospital stay (P < 0.001) but not with infectious complications (P = 0.21). However, postoperative glucose concentration was not found to be an independent risk factor for prolonged in-hospital stay in multivariate analysis (P = 0.20).

Conclusion

Our data indicate that postoperative hyperglycaemia is more likely to be a risk marker than a risk factor in patients undergoing highly invasive surgery for oesophageal cancer. We hypothesize that patients with a low prevalence of vascular disease may benefit less from intensive insulin therapy.
Negative regulation of Smad2 by PIASy is required for properXenopusmesoderm formation
Authors: Daniels Maki , Shimizu Kazuya , Zorn Aaron M. , Ohnuma Shin-ichi
Published: October 2004

Mesoderm induction and patterning are primarily regulated by the concentration of locally expressed morphogens such as members of the TGFβsuperfamily. Smad2 functions as a transcription factor to regulate expression of mesodermal genes downstream of such morphogens. We have identified Xenopus PIASy (XPIASy), a member of the PIAS family, by yeast two-hybrid screening using Xenopus Smad2 (XSmad2) as a bait. During mesoderm induction, XPIASy is expressed in the animal half of embryos with a ventral high-dorsal low gradient at the marginal zone. XPIASyexpression is positively and negatively regulated by activities of the XSmad2 and Wnt pathways, respectively. Interestingly, inhibition of XPIASy by morpholinos induces elongation of animal caps with induction of mesoderm genes even in the absence of their morphogen-mediated activation. In addition, their introduction into the ventral marginal zone results in a secondary axis formation. Gain-of-function analysis revealed that XPIASy inhibits mesoderm induction by specific and direct downregulation of XSmad2 transcriptional activity. These observations indicate that XPIASy functions as an essential negative regulator of the XSmad2 pathway to ensure proper mesoderm induction at the appropriate time and in the appropriate region, and suggest that both the initial step of morphogen-mediated activation of the XSmad2 pathway and regulation of the final downstream transcription step have crucial roles in mesoderm induction and patterning.
Conserved and acquired features ofneurogenin1regulation
Authors: Blader Patrick , Lam Chen Sok , Rastegar Sepand , Scardigli Raffaella , Nicod Jean-Christophe , Simplicio Nicolas , Plessy Charles , Fischer Nadine , Schuurmans Carol , Guillemot François , Strähle Uwe
Published: October 2004

The telencephalon shows vast morphological variations among different vertebrate groups. The transcription factor neurogenin1(ngn1) controls neurogenesis in the mouse pallium and is also expressed in the dorsal telencephalon of the evolutionary distant zebrafish. The upstream regions of the zebrafish and mammalian ngn1 loci harbour several stretches of conserved sequences. Here, we show that the upstream region of zebrafish ngn1 is capable of faithfully recapitulating endogenous expression in the zebrafish and mouse telencephalon. A single conserved regulatory region is essential for dorsal telencephalic expression in the zebrafish, and for expression in the dorsal pallium of the mouse. However, a second conserved region that is inactive in the fish telencephalon is necessary for expression in the lateral pallium of mouse embryos. This regulatory region, which drives expression in the zebrafish diencephalon and hindbrain, is dependent on Pax6 activity and binds recombinant Pax6 in vitro. Thus, the regulatory elements of ngn1 appear to be conserved among vertebrates, with certain differences being incorporated in the utilisation of these enhancers, for the acquisition of more advanced features in amniotes. Our data provide evidence for the co-option of regulatory regions as a mechanism of evolutionary diversification of expression patterns, and suggest that an alteration in Pax6expression was crucial in neocortex evolution.
Sound localization in a small passerine bird: discrimination of azimuth as a function of head orientation and sound frequency
Authors: Nelson Brian S. , Suthers Roderick A.
Published: October 2004

Sound localization is critical to communication when signalers are distributed widely in space and when reverberations that accumulate over distance might otherwise degrade temporal patterns in vocalizations. We readdress the accuracy with which a small passerine bird, the eastern towhee, Pipilo erythrophthalmus L., is able to resolve azimuth in the field. We then report results from two-alternative forced-choice (2AFC) experiments in which three of four subjects were able to discriminate an estimated speaker separation angle of approximately 7°. Subjects oriented laterally when discriminating azimuth in the 2AFC task and each subject preferred a different head orientation. Side biases occurred as a function of head orientation and,as a consequence, we conducted a second 2AFC experiment in which subjects were required to discriminate between two closely spaced lights. Subjects oriented similarly in this visual task, however, side biases did not occur as a function of head orientation. Despite side biases in the auditory task,performance generally declined when subjects were played tones with frequencies near ∼3 kHz.
Tuna comparative physiology
Authors: Graham Jeffrey B. , Dickson Kathryn A.
Published: October 2004

Thunniform swimming, the capacity to conserve metabolic heat in red muscle and other body regions (regional endothermy), an elevated metabolic rate and other physiological rate functions, and a frequency-modulated cardiac output distinguish tunas from most other fishes. These specializations support continuous, relatively fast swimming by tunas and minimize thermal barriers to habitat exploitation, permitting niche expansion into high latitudes and to ocean depths heretofore regarded as beyond their range.
Computational Problems in Noisy SNP and Haplotype Analysis: Block Scores, Block Identification, and Population Stratification
Authors: Kimmel Gad , Sharan Roded , Shamir Ron
Published: October 2004

The study of haplotypes and their diversity in a population is central to disease-association research. We study several problems arising in haplotype block partitioning. Our objective function is the total number of distinct haplotypes in blocks. We show that the problem is NP-hard when there are errors or missing data, and provide approximation algorithms for several of its variants. We also give an algorithm that solves the problem with high probability under a probabilistic model that allows noise and missing data. In addition, we study the multipopulation case, where one has to partition the haplotypes into populations and seek a different block partition in each one. We provide a heuristic for that problem and use it to analyze simulated and real data. On simulated data, our blocks resemble the true partition more than the blocks generated by the LD-based algorithm of Gabriel et al (2002). On single-population real data, we generate a more concise block description than do extant approaches, with better average LD within blocks. The algorithm also gives promising results on real two-population genotype data.
Editorial Notes
Authors: Kemerer Chris F.
Published: October 2004

This month marks the announcement of some forthcoming changes in the editorial board of Information Systems Research.
Subversion of myths: high and low cultures in Donald Barthelme’s Snow White and Robert Coover’s Briar Rose
Authors: Kusnír Jaroslav
Published: October 2004

This paper analyses Donald Barthelme’s and Robert Coover’s postmodern novels Snow White and Briar Rose and the way both authors, especially through the use of parody and irony, undermine traditional genres of popular literature and, at the same time, give both
an intramural critique of traditional narrative techniques (and the vision of the world they produce) and the extramural critique of consumerism and popular culture. In addition to this, with the analysis of Coover’s novel the emphasis is on the imagery of dreams and dreaming understood
as the manifestation of undermining of some aspects of Freudian theories.
The Clinical Usefulness of the Measurement of Cytokines
Authors: Bienvenu Jacques , Monneret Guillaume , Fabien Nicole , Revillard Jean Pierre
Published: October 2004

The utilization of accurate and sensitive methods for the measurement of cytokines in body fluids is prerequisite for the proper use of these mediators in clinical practice. Many factors contribute to the complexity of cytokine quantitation. Bioassays historically preceded immunoassays, which are now very popular, but there is a need for standardization. Nevertheless, due to the local effects of cytokines, the study of their blood levels is of limited value for an understanding of the pathophysiology of these mediators. This explains the development of alternative approaches to assess the ability of cells to produce cytokines. These include the Enzyme-Linked Immuno Spot Assay (ELISPOT), the measurement of cell-associated cytokines by flow cytometry, and the study of cytokine secretion by isolated peripheral blood mononuclear cells or by whole blood test. All these techniques, associated with a local detection of cytokines by immunohistochemistry orin situhybridization and reverse transcriptase polymerase chain reaction, appear to be complementary tools for a better understanding of the biology of cytokines. Selected examples of possible clinical applications related to infectious diseases, cancer, autoimmune diseases, allergy, transplantation and preclinical evaluation of drugs and biotechnology products are given.
Macro Lactate Dehydrogenase in a Patient with Myocarditis
Authors: Liu Ze-Jun , Zhang Yong
Published: October 2004

Elevated level of plasma lactate dehydrogenase activity in a patient with myocarditis was found to be due to the presence of lactate dehydrogenase-immunoglobulin complexes in circulation. The complexes were demonstrated by counter-immunoelectrophoresis. In this case, three immunoglobulins (IgG, IgA and IgM) and two types of light chains (λ and κ) combined with lactate dehydrogenase
Elimination of Serum Complexed Prostate-Specific Antigen after Radical Retropubic Prostatectomy
Authors: Stephan Carsten , Jung Klaus , Brux Brigitte , Lein Michael , Sinha Pranav , Schnorr Dietmar , Loening Stefan A.
Published: October 2004

Total prostate-specific antigen (PSA) and complexed PSA were determined in venous blood from 12 patients with prostate cancer before and after radical prostatectomy by using Immuno 1 PSA assays. The elimination kinetics of complexed PSA were compared with that of total PSA. Nearly constant concentrations of complexed PSA were found during the first six hours after surgery, in contrast to the rapid elimination of free PSA and the significant decrease of total PSA. From day one to ten there was a continuous and nearly identical decrease of complexed PSA compared to total PSA. Our findings suggest that the initial rapid decrease of free PSA immediately after operation could be caused by formation of new PSA-complex.
Evaluation of the ADVIA® Centaur™ TSH-3 Assay
Authors: Vogeser Michael , Weigand Michael , Fraunberger Peter , Fischer Heike , Cremer Peter
Published: October 2004

An analytical evaluation of the thyroid stimulating hormone (TSH-3) assay on the Bayer ADVIA® CentaurTM immunoassay system was performed. General analytical requirements (linearity, resistance to typical interferences, absence of a carry-over effect) were fulfilled and reproducibility was satisfactory. Inter-assay coefficient of variation (CV) of a human serum pool with a concentration of 0.014 mU/l was 22.3%; at concentrations between 0.26 and 83 mU/l CV was below 6%. Method comparison study demonstrated close agreement of TSH results compared to those obtained with the Roche Elecsys® 2010 TSH assay (ADVIA Centaur = 1.08 × Elecsys−0.18 mU/l; r=0.987; n=324). Handling and practicability of the ADVIA Centaur system proved to be convenient with a very high sample throughput. We conclude that the ADVIA Centaur TSH-3 assay meets requirements for clinical use.
Analytical and Clinical Evaluation of Troponin I Determination on Dimension RXL-HM
Authors: Hafner Gerd , Peetz Dirk , Dati Francesco , Post Felix , Blankenberg Stefan , Peivandi Ali A. , Sucké Bernd , Rupprecht Hans-Jürgen , Dahm Manfred , Kleist Reiner von , Prellwitz Winfried
Published: October 2004

The evaluation of cardiac troponin I (cTnI) on the Dimension RxL®-HM analyzer is presented. The one-step enzyme immunoassay is based on two cTnI specific monoclonal antibodies. Performed on a separate module of the analyzer, assay-time is 17 minutes. Using as criterion a between-run impression CV <20% the functional limit of detection was set at 0.1 μg/l. Cutoff level for minor myocardial damage of 0.1 μg/l was found. In Duchenne's dystrophy, patients showed increased cardiac Troponin T (cTnT) but no increased cTnI. In patients with a history of coronary heart disease undergoing chronic hemodialysis, cTnT and cTnI were increased. In different patients with submassive pulmonary embolism, increased cTnI was determined. In coronary artery bypass surgery without perioperative myocardial infarction, patients with extracorporeal circulation showed significantly higher cTnI at 24 h after surgery than those with minimal cardiac surgery. In patients with unstable angina, increased cTnI was found more often than on Stratus analyzer. In conclusion, the new assay is a very sensitive cTnI assay, fast and easy to perform in parallel to enzyme and substrate assays.
Use of Ion-Selective Electrodes for Blood-Electrolyte Analysis. Recommendations for Nomenclature, Definitions and Conventions
Authors: Burnett Robert W. , Covington Arthur K. , Fogh-Andersen Nils , Külpmann Wolf R. , Lewenstam Andrzej , Maas Anton H.J. , Müller-Plathe Oswald , VanKessel Antonius L. , Zijlstra Willem G.
Published: October 2004

This paper will familiarize the reader with the terms used to describe the behavior of ion-selective electrodes, particularly in relation to their use in clinical chemistry for determination of blood electrolyte cations. It serves as an introduction to a series of papers dealing with important cations in blood, namely calcium, sodium, and potassium. The detailed relationships between the ion activity determined by means of ion-selective electrode potentiometry in undiluted specimens, and the total substance concentration measured by flame atomic-emission spectrometry are described by flow chart and equations. Adoption of a convention for reporting results is recommended.

The Working Group on Selective Electrodes has taken into account recent revisions of IUPAC recommendations on nomenclature and selectivity coefficient determinations for ion-selective electrodes, and benefited from the experience of a member of the WG, who was also involved in the IUPAC discussions. Nomenclature for determined quantities follows previous IUPAC/IFCC joint recommendations.
Red Blood Cell Osmotic Fragility Confidence Intervals: a Definition by Application of a Mathematical Model
Authors: Fernández-Alberti Alejandra , Fink Nilda E.
Published: October 2004

The red blood cell osmotic fragility test is based on the measure of the resistance of red blood cells to lysis as a function of decreasing NaCl concentration. Up to now, several methods have been used for recording these data, but for the first time, the human red blood cell osmotic fragility confidence interval using the Orcutt mathematical model was determined. The absorbance of the hemoglobin measured at 540 nm, released by the red blood cells of 40 healthy adult individuals, was fitted to the equation Absorbance=p3 erfc ([NaCl] − p1/p2); p3 measures one half the absorbance produced by maximum red blood cell hemolysis, p1 is the [NaCl] producing 50% red blood cell hemolysis, and p2 is the dispersion in [NaCl] producing red blood cell hemolysis. Confidence intervals (mean±SD) for the three parameters were as follows: p1=4.2718±0.1848; p2= 0.1947±0.0391, and p3=0.5568+0.0426. The usefulness of this osmotic fragility data analysis method using two pathological samples (β-thalassemia minor and hereditary spherocytosis) was demonstrated. Parameters of the fitted data were compared with those obtained by the conventional recording method of Beutler.
Assessment of CA 15.3, CEA and TPA Concentrations during Monitoring of Breast Cancer
Authors: Sölétormos György , Petersen Per Hyltoft , Dombernowsky Per
Published: October 2004

The variability of the tumor markers cancer antigen (CA) 15.3, carcinoembryonic antigen (CEA) and tissue polypeptide antigen (TPA) during steady state concentrations and the rate of increase during progression is described. One hundred and ninety-two patients were monitored during first-line chemotherapy for metastatic breast cancer and during follow-up. Blood specimens were sampled approximately every four weeks. Steady state concentrations were registered for 77 (CA 15.3), 96 (CEA), and 127 (TPA) patients with below cutoff level values and for 28 (CA 15.3), 25 (CEA), and 11 (TPA ) patients with above cutoff level values. Clinical and marker progression was registered for 75 (CA 15.3), 62 (CEA), and 57 (TPA) patients. The coefficients of total variation of steady state concentrations (comprising the intra- and interassay analytical imprecision and the within subject biological variation) were higher below (14.9% CA 15.3, 15.4% CEA, 25.9% TPA) than above cutoffs (9.6% CA 15.3, 6.0% CEA, 19.9% TPA). The variability was similar for CA 15.3 and CEA but higher for TPA. During progression the rates of increase in concentrations were similar for CA 15.3 (0.0257) and CEA (0.0214) and lower than for TPA (0.0346). Our data indicate that criteria for assessment of sequential tumor marker concentrations should consider the marker in question, the steady state variability, the cutoff value, and the rate of increase during disease progression.
Determination of Plasma Methoxyamines
Authors: Pallant Agnès , Mathian Bruno , Prost Laurent , Theodore Christine , Patricot Marie-Claude
Published: October 2004

The determination of plasma methoxyamines is the most informative parameter for the diagnosis of pheochromocytoma. Very good sensitivity and specificity are necessary for this. The measurement of deconjugated (free plus sulfate—conjugated) metanephrines is more useful. Concentrations are 10—fold higher than free metanephrine concentrations. The methodology generally uses a column purification and high performance liquid chromatography with electrochemical detection. We have tested six commercial columns used for the purification step. We chose a rapid and reliable method with a mixture of strong cation-exchange and strong anion-exchange groups bonded onto a silica column. This protocol has been validated with samples of plasma from normal subjects, healthy elderly people, renal failure patients and patients with pheochromocytoma.
A Model for Setting Analytical Quality Specifications and Design of Control for Measurements on the Ordinal Scale
Authors: Petersen Per Hyltoft , Sandberg Sverre , Fraser Callum G. , Goldschmidt Henk
Published: October 2004

A model for characterization of measurements on the ordinal scale is presented. It is based on transformation of the calculated fractions (fractiles) of positives from measurements on samples with known concentrations to a probit-natural log (probit-ln) scale. Such measurements could be made by other methods on ratio or difference scales but, for convenience (for example for speed or low cost), are measured on the ordinal scale by “simple” methods. The model is examined, and verified, using three examples from published data (haemoglobin, glucose, and leukocytes) and an external quality assessment survey on measurements of streptococcus. We show that it is possible to obtain reliable analytical quality specifications and to establish design of control systems for measurements on the ordinal scale. It is concluded that the presented probit-ln model for the ordinal scale is a tool which can improve and facilitate (i) characterizing methods with measurements on the ordinal scale, (ii) defining analytical quality specifications, (iii) designing external assessment as well as internal control schemes, (iv) validation of methods with measurements on the ordinal scale according to the analytical quality specifications, and further, (v) reduction of the number of samples required for method validation and the number of replicate measurements needed.
Evaluation of the Roche Diagnostics LightCycler-Apo B 3500 Mutation Detection Kit
Authors: Nauck Markus , Wieland Heinrich , März Winfried
Published: October 2004

Familial defective apolipoprotein (apo) B-100 is an autosomal codominant disorder associated with hypercholesterolemia and an increased risk of coronary artery disease. Two independent mutations affecting the codon 3500 (Arg3500→Gln and Arg3500→Trp) have been shown to cause ligand-defective apo B-100. Identification of carriers of these mutations is an important step in the risk stratification of individuals and families with hypercholesterolemia.

We evaluated a homogeneous assay for detection of mutations at codon 3500 that combines rapid-cycle PCR with allele-specific fluorescent probe melting profiles for product genotyping. This single-tube analysis is performed on the LightCycler™, a microvolume fluorimeter integrated with a thermal cycler. Continuous acquisition of fluorescence data during a melting curve analysis at completion of PCR allows the detection of mutations, as loss of fluorescence occurs in an allele-specific manner. By plotting melting peaks, the three apo B-100 alleles were readily distinguishable. Using this method, genotyping of 32 samples is completed within 40 min without the need for any post-PCR sample manipulation, thereby eliminating the risks of end-product contamination and sample tracking errors. The specific detection of mutations at codon 3500 of the apo B gene on the LightCycler™ is a rapid and reliable method that is ideally suitable for typing both small and large numbers of samples.
Trace Element Reference Values in Serum Determined by Inductively Coupled Plasma Atomic Emission Spectrometry
Authors: Rahil-Khazen Reem , Bolann Bjørn J. , Ulvik Rune J.
Published: October 2004

Serum reference values for Ba, B, Cd, Cu, Fe, Mn, Li, Se, Sr, and Zn in 141 healthy Norwegians were determined. The trace element concentrations were determined by the inductively coupled plasma atomic emission spectrometry technique that we have recently validated. The reference intervals were established according to the recommendations of the International Federation of Clinical Chemistry and Laboratory Medicine. Also coverage intervals with coverage uncertainties were calculated according to the International Union of Pure and Applied Chemistry. The population studied consisted of 69 men and 72 women of the ages 21–87 years. The effects of gender, age, smoking, and oral contraceptives on serum levels of trace elements were investigated. Median concentrations of the different trace elements in (μmol/l) were as follows: Ba (0.44), B (1.50), Cd (0.004), Cu (17.1), Fe (21.4), Li (0.06), Mn (0.003), Se (1.26), Sr (0.17), and Zn (13.3). An increase in serum Ba and Sr was detected with age. These metals and Se were also significantly higher in women over 50 years of age in comparison to younger women. Women had higher serum Cu than men and those on oral contraceptives had higher serum Cu and Fe. Serum B tended to increase with age, while it was significantly reduced with smoking.
Comparative Multicentre Study of a Panel of Thyroid Tests Using Different Automated Immunoassay Platforms and Specimens at High Risk of Antibody Interference
Authors: Martel Julie , Després Normand , Ahnadi Charaf E. , Lachance Jean-François , Monticello James E. , Fink Guy , Ardemagni Anna , Banfi Giuseppe , Tovey John , Dykes Peter , John Rhys , Jeffery Jinny , Grant Andrew M.
Published: October 2004

The introduction of automation for immunoassays in recent years has brought about important and evident improvements in assay precision. Increasing standardization and comparability between platforms should enable the development of clinical guidelines and diagnostic algorithms for appropriate clinical decision making. A continuing source of variation between different automated immunoassay platforms is the sporadic effect of interfering antibodies or substances, thus causing aberrant results not supporting the patient's clinical status.

The aim of this study was to describe current thyroid panel variation between automated immunoassay platforms including population specimens at risk of antibody interference. A multisite design with laboratories in three different countries using four different automated immunoassay platforms (Roche-Boehringer Mannheim Elecsys® (Italy), Roche-Boehringer Mannheim ES300® (Wales), Bayer Immuno 1® and the Bayer ACS:180® evaluated the thyroid panel of thyrotropin (TSH), triiodothyromine (T3), free thryroxine (FT4) and free triiodothyronine (FT3). A common set of 158 randomly selected patient samples of non-thyroid and thyroid disorders, with and without treatment, was tested. Included were 62 patient samples at risk for endogenous antibody interference with high antimicrosomal antibody, anti-TSH receptor antibody and increased rheumatoid factor sub-populations.

Across all controls and between platforms, precision measurements were comparable and varied between 0.7% and 12.8% for TSH, 2.8% and 13% for FT4, 1.8% and 10.5% for FT3 and 3.1% and 16% for T3 assay. Acceptable correlation and reproducibility were found between the three Bayer Immuno 1 platforms at each country's site with all four thyroid panel assays demonstrating r-values of 0.989 to 1.000 and slopes of 0.915 to 1.078. Comparisons between the different platforms showed acceptable correlation for all thyroid panel assays. Specimens containing rheumatoid factor were associated with a significantly increased variation between systems for the FT4 and FT3 assays (p < 0.01). This effect did not appear to be selective for a given platform. For specimens with raised autoimmune antibodies and therefore at risk of assay antibody interference, no variation could be observed between the platforms.
Reduction of Weathering Degradation of Wood Through Plasma-Polymer Coating
Authors: Denes Agnes R. , Young Raymond A.
Published: October 2004

A novel plasma-enhanced coating for wood substrates has been developed which diminishes the degradation of wood under simulated harsh environmental conditions. Reflective (zinc oxide) and electromagnetic radiation (EMR)-absorbent (benzotriazole, 2-hydroxybenzophenone, phtalocyanine, and graphite) substances were incorporated into a liquid phase, high-molecular-weight polydimethylsiloxane and deposited as thin layers on wood surfaces. The macromolecular films, containing the dispersed materials, were then converted into a three-dimensional solid state network by exposure to a 30 kHz-oxygen-RF-plasma. The discharge induced chemistry and altered surface topographies in the surface layers were monitored by survey and high resolution Electron Spectroscopy for Chemical Analysis, Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy, and Scanning Electron Microscopy. The surface characteristics and the resistance to weathering of the plasma treated substrates were evaluated and compared to the properties of un-modified samples.