bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrospray mass spectrometry in the differentiation of some isomeric trimethylfurocoumarins
Authors: Basso Elisa , Chilin Adriana , Guiotto Adriano , Traldi Pietro 
Published: December 2003

AbstractElectrospray mass spectrometry (ES‐MS) was successfully employed for the structural differentiation of six isomeric trimethylfurocoumarins of possible pharmaceutical interest. Two different approaches were employed. The first was based on MSn experiments of MH+ ions. Although the product ion spectra of MH+ of the isomers are very similar, the MS3 spectra of the collisionally generated [MHCO]+ ions show some characteristic differences. The second approach was based on complexation of the molecules with Li+, Na+ and K+ using ESI‐MS of sample solutions containing alkali ions in a 100:1 molar ratio with respect to the analyte. Significant differences were observed in complex production yields, and these were related to the dimension of the alkali ion and to the steric availability of chelating groups in the different isomers. Copyright © 2003 John Wiley & Sons, Ltd.
Characteristic fragmentation of bacteriohopanepolyols during atmospheric pressure chemical ionisation liquid chromatography/ion trap mass spectrometry
Authors: Talbot Helen M. , Summons Roger , Jahnke Linda , Farrimond Paul 
Published: December 2003

AbstractBacteriohopanepolyols (BHPs) fragment via characteristic pathways during atmospheric pressure chemical ionisation liquid chromatography/ion trap mass spectrometry (APCI‐LC/MSn). Comparison of the MS2 spectra of bacteriohopane‐32,33,34,35‐tetrol (BHT) and 2β‐methylbacteriohopane‐32,33,34,35‐tetrol has confirmed the previously proposed ring‐C cleavage occurring between C‐9 and 11 and C‐8 and 14. This fragmentation, diagnostic of all hopanoids, also occurs in BHPs containing an amino group (‐NH2) at C‐35 although the higher relative stability of the ion limits this fragmentation to a minor process after protonation of the basic nitrogen function. Studies of a number of cell cultures including a prochlorophyte (Prochlorothrix hollandica) and a cyanobacterium (Chlorogloeopsis LA) demonstrate the power of this technique to detect composite BHPs with a complex biological functionality at C‐35. We also report the first observation of intact pentafunctionalised bacteriohopanepolyols using this method. Copyright © 2003 John Wiley & Sons, Ltd.
The use of nonpolar matrices for matrix‐assisted laser desorption/ionization mass spectrometric analysis of high boiling crude oil fractions
Authors: Robins Chad , Limbach Patrick A. 
Published: December 2003

AbstractMatrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) with nonpolar matrices has been investigated for its applicability to the characterization of atmospheric resid crude oil fractions. The data obtained by use of nonpolar matrices was compared with that from polar matrices as well as from direct LDI‐MS and field ionization mass spectrometry. Nonpolar matrices, such as anthracene or 9‐cyanoanthracene, yield only a single radical molecular cation upon LDI. Thus, no interfering matrix‐related ions are present during the MALDI‐TOFMS analysis of the crude oil sample. Nonpolar matrices yield molecular mass distributions from linear mode MALDI‐TOFMS that are comparable to distributions found with LDI‐MS. An advantage of nonpolar matrices is the increased production of analyte ions, which allows reflectron mode MALDI‐TOFMS to be performed. Nonpolar matrices are also shown to be less sensitive to solvent and sample preparation conditions than conventional polar matrices. These results suggest that nonpolar matrices may be favorable alternatives to more traditional polar or acidic matrices commonly used in the MALDI mass spectral characterization of crude oil related samples. Copyright © 2003 John Wiley & Sons, Ltd.
Probabilistic approach to developing nephropathy in diabetic patients with retinopathy
Authors: Ballone Enzo , Colagrande Vittorio , Di Nicola Marta , Di Mascio Rocco , Di Mascio Claudio , Capani Fabio 
Published: December 2003

AbstractIt is well known that diabetes is a risk factor for many complications including diabetic retinopathy and nephropathy. An interesting question is whether a diabetic patient who has developed a retinopathy develops a nephropathy sooner. We approached this problem by calculating the conditional probability that a diabetic patient will develop a second complication, given that they had already developed the first complication. We also propose the application of Bayes' formula to estimate the probability of developing the second complication, given that the first complication had developed previously. We compared these two methods by applying them to analyse 5473 patients with type 2 diabetes. The results of our experience are described. Copyright © 2003 John Wiley & Sons, Ltd.
Comparison of case‐cohort estimators based on data on premature death of adult adoptees
Authors: Petersen Liselotte , Sørensen Thorkild I. A. , Andersen Per Kragh 
Published: December 2003

AbstractA case‐cohort sample of adoptees was collected to investigate genetic and environmental influences on premature death, which motivated us to supplement existing simulation results to explore the performance of various estimators proposed for case‐cohort samples of survival data. We studied six regression coefficients estimators, which differ with regard to the weighting scheme used in a pseudo‐likelihood function, and two different estimators of their variances. Compared to earlier simulation studies, we changed the following conditions: type of explanatory variable, the distribution of lifetimes, and the percentage of deaths in the full cohort. The latter condition affected the performance of the estimated variances of the regression coefficients, where we found a systematic bias of the estimator, proposed by Self and Prentice, dependent on the percentages of deaths. This dependence of percentages of death was different for different sizes of case‐cohort studies. A robust variance estimator showed a better overall performance. The estimators of regression coefficients compared did not differ much, the estimators proposed by Kalbfleisch and Lawless and by Prentice performing very well. Results of the case‐cohort data of adoptees were not in conflict with earlier findings of a moderate genetic influence on premature death in adulthood. Copyright © 2003 John Wiley & Sons, Ltd.
Proper metrics for clinical trials: transformations and other procedures to remove non‐normality effects
Authors: Lachenbruch Peter A. 
Published: December 2003

AbstractA simulation study was performed to study the effects of non‐normality and to examine procedures to ameliorate possible loss of power when data are incorrectly assumed to be normally distributed. It was found that only distributions with high asymmetry or heavy tails seriously affect the t‐test. The Box–Cox likelihood ratio test appears to have some advantages over the others, but this must be offset by the greater complexity in making the results understandable to non‐statisticians. The variability in outcomes with the different procedures demonstrates the importance of specifying such proceduresa priori. Published in 2003 by John Wiley & Sons, Ltd.
The analysis of the influence of birth order and other factors in multiple birth data
Authors: Davidov Ori , Murad Havi , Lusky Ayala , S Shinwell Eric , Reichman Brian , Freedman Laurence 
Published: December 2003

AbstractWe compare three methods which can be used to analyse theinfluence of birth order and other factors on health outcomes inmultiple birth data. We consider marginal models based ongeneralized estimating equations (GEE) and two kinds ofconditional models; conditional logistic regression (CLR) andmixed effects models (MEM). Although the models may be writtensimilarly, there are differences in both the interpretation andthe numerical values assigned to the parameters. Our mainconclusion is that GEE and MEM are preferable to CLR since theyprovide more flexibility in dealing with missing values andcovariates. The choice between GEE and MEM is less obvious anddepends on the data, the parameter of interest and statisticalpower. Copyright © 2003 John Wiley & Sons, Ltd.
Comparison of JavaServer Pages and XSLT: a software engineering perspective
Authors: Dunkel Jürgen , Bruns Ralf , Holitschke Andreas 
Published: December 2003

AbstractProfessional Web applications present their content and services by means of dynamically generated Web pages to the user—normally HTML pages. Basically, there are two different technologies available for dynamic Web page generation—JavaServer Pages and XML/XSLT. In this paper the alternative technologies are compared from a software engineering perspective.The basic concepts of JavaServer Pages and XML/XSLT are briefly explained with respect to Web page generation. A universal software architecture of the server side presentation tier is introduced and it is shown how both technologies fit into the universal architecture. Its fundamental idea is the clear separation of concerns according to the well‐established model‐view‐controller design pattern. The proposed architecture has proven its applicability in several enterprise applications. The main part of the paper deals with the comparison of JavaServer Pages and XML/XSLT. Quality criteria well‐established in software engineering practice are discussed with respect to JavaServer Pages and XML/XSLT, e.g. maintainability, extensibility, reusability, efficiency, portability, integration of methods and tools. The main emphasis is laid on the support of the model‐view‐controller pattern, since it is the most established design principle for user interface design. Copyright © 2003 John Wiley & Sons, Ltd.
An extensible probe architecture for network protocol performance measurement
Authors: Watson David , Malan G. Robert , Jahanian Farnam 
Published: December 2003

AbstractThis paper describes the architecture, implementation, and application of Windmill, a passive network protocol performance measurement tool. Windmill enables experimenters to measure a broad range of protocol performance metrics both by reconstructing application‐level network protocols and by exposing the underlying protocol layers' events. Windmill is split into three functional components: a dynamically compiled Windmill Protocol Filter (WPF), a set of abstract protocol modules, and an extensible experiment engine. To demonstrate Windmill's utility, we present the results from several experiments. The first set of experiments validates a possible cause for the correlation between Internet routing instability and network bandwidth usage. The second set of experiments highlights Windmill's ability to act as a driver for a complementary active Internet measurement infrastructure, its ability to perform online data reduction, and the non‐intrusive measurement of a closed system. Copyright © 2003 John Wiley & Sons, Ltd.
A Logic for Schema-Based Program Development
Authors: Henson Martin C. , Reeves Steve 
Published: December 2003

Abstract.
We show how a theory of specification refinement and program development can be constructed as a conservative extension of our existing logic for Z. The resulting system can be set up as a development method for a Z-like specification language, or as a generalisation of a refinement calculus (with a novel semantics). In addition to the technical development we illustrate how the theory can be used in practice.
Deep Semantic Links of TCSP and Object-Z: TCOZ Approach
Authors: Mahony Brendan , Dong Jin Song 
Published: December 2003

Abstract.
Formal methods can be used in effective combination only if the semantic links between individual methods are clearly established. This paper discusses the semantic design of TCOZ, a language blended from Object-Z and TCSP. The semantic model adopted is the infinite timed failures model of TCSP, extended to include initial state and update events for modelling operations on internal state. An infinite trace model has been used so as to ensure proper account is taken of the potentially unbounded non-determinism allowed by Z schemas.
Architectural Specifications in CASL
Authors: Bidoit Michel , Sannella Donald , Tarlecki Andrzej 
Published: December 2003

Abstract.

One of the most novel features of C

ASL

, the Common Algebraic Specification Language, is the provision of so-called
architectural specifications
for describing the modular structure of software systems. A brief discussion of refinement of C

ASL

specifications provides the setting for a presentation of the rationale behind architectural specifications. This is followed by some details of the features provided in C

ASL

for architectural specifications, hints concerning their semantics, and simple results justifying their usefulness in the development process.
Institution Morphisms
Authors: Goguen Joseph , Roşu Grigore 
Published: December 2003

Abstract.Institutions formalise the intuitive notion of logical system, including syntax, semantics, and the relation of satisfaction between them. Our exposition emphasises the natural way that institutions can support deduction on sentences, and inclusions of signatures, theories, etc.; it also introduces terminology to clearly distinguish several levels of generality of the institution concept. A surprising number of different notions of morphism have been suggested for forming categories with institutions as objects, and an amazing variety of names have been proposed for them. One goal of this paper is to suggest a terminology that is uniform and informative to replace the current chaotic nomenclature; another goal is to investigate the properties and interrelations of these notions in a systematic way. Following brief expositions of indexed categories, diagram categories, twisted relations and Kan extensions, we demonstrate and then exploit the duality between institution morphisms in the original sense of Goguen and Burstall, and the ‘plain maps’ of Meseguer, obtaining simple uniform proofs of completeness and cocompleteness for both resulting categories. Because of this duality, we prefer the name ‘comorphism’ over ‘plain map’; moreover, we argue that morphisms are more natural than comorphisms in many cases. We also consider ‘theoroidal’ morphisms and comorphisms, which generalise signatures to theories, based on a theoroidal institution construction, finding that the ‘maps’ of Meseguer are theoroidal comorphisms, while theoroidal morphisms are a new concept. We introduce ‘forward’ and ‘semi-natural’ morphisms, and develop some of their properties. Appendices discuss institutions for partial algebra, a variant of order sorted algebra, two versions of hidden algebra, and a generalisation of universal algebra; these illustrate various points in the main text. A final appendix makes explicit a greater generality for the institution concept, clarifies certain details and proves some results that lift institution theory to this level.
A New Approach to Abstract Syntax with Variable Binding
Authors: Gabbay Murdoch J. , Pitts Andrew M. 
Published: December 2003

Abstract.
The permutation model of set theory with atoms (FM-sets), devised by Fraenkel and Mostowski in the 1930s, supports notions of ‘name-abstraction’ and ‘fresh name’ that provide a new way to represent, compute with, and reason about the syntax of formal systems involving variable-binding operations. Inductively defined FM-sets involving the name-abstraction set former (together with Cartesian product and disjoint union) can correctly encode syntax modulo renaming of bound variables. In this way, the standard theory of algebraic data types can be extended to encompass signatures involving binding operators. In particular, there is an associated notion of structural recursion for defining syntax-manipulating functions (such as capture avoiding substitution, set of free variables, etc.) and a notion of proof by structural induction, both of which remain pleasingly close to informal practice in computer science.
Three Inadequate Models
Authors: Plotkin Gordon 
Published: December 2003

Abstract.
The connection between operational and denotational semantics is of longstanding interest in the study of programming languages. The emphasis has been on positive results, whether for adequacy or full abstraction. One normally considers the standard solution of an evident natural domain equation for the language; this is generally adequate but not fully abstract if one uses any of the usual categories of domains. One then tries other categories to get improved results.

Here we restrict ourselves to a standard category of domains and show, for an untyped λ-calculus with arithmetic, that inadequate models exist if one considers non-standard solutions to the domain equation. One model is inadequate, simpliciter; a second is adequate but inadequate when the language is extended by a “parallel or” construct; the third is adequate in the latter sense, but in it the
Y
-combinator does not denote the least fixed point operator.

We also consider whether it is possible to do better than the standard solution as regards full abstraction. Surprisingly this question only makes sense for solutions which are adequate for the extended language. For these the standard solution is indeed closest to full abstraction, justifying the use of non-standard categories.
False Loop Detection in the IEEE 1394 Tree Identify Phase
Authors: Romijn Judi 
Published: December 2003

Abstract.

The physical layer of the IEEE 1394 (FireWire, i-Link) architecture contains a protocol for spanning a tree in the network topology, which fails if the topology contains a loop. We show that the timing requirements for both the 1394-1995 and 1394a-2000 standards are too lenient: these allow for scenarios in which there is no loop in the topology, but the tree-spanning protocol does detect one. The scenarios are found by the model checker U

PPAAL

.
Exposure to violent video games increases automatic aggressiveness
Authors: Uhlmann Eric , Swanson Jane 
Published: December 2003

ABSTRACTThe effects of exposure to violent video games on automatic associations with the self were investigated in a sample of 121 students. Playing the violent video game Doom led participants to associate themselves with aggressive traits and actions on the Implicit Association Test. In addition, self‐reported prior exposure to violent video games predicted automatic aggressive self‐concept, above and beyond self‐reported aggression. Results suggest that playing violent video games can lead to the automatic learning of aggressive self‐views.
Calcium drives fusion of SNARE‐apposed bilayers
Authors: Jeremic Aleksandar , Kelly Marie , Cho Jin Ah , Cho Sang‐Joon , Horber J.K.Heinrich , Jena Bhanu P. 
Published: December 2003

AbstractN‐ethylmalemide‐sensitive factor attachment protein receptor (SNARE) has been proposed to play a critical role in the membrane fusion process. The SNARE complex was suggested to be the minimal fusion machinery. However, there is mounting evidence for a major role of calcium in membrane fusion. Hence, the role of calcium in SNARE‐induced membrane fusion was the focus of this study. It revealed that recombinant v‐SNARE and t‐SNARE, reconstituted into separate liposomes, interact to bring lipid vesicles into close proximity, enabling calcium to drive fusion of opposing bilayers. Exposure to calcium triggered vesicle fusion at both, high potency and efficacy. The half‐time for calcium‐induced fusion of SNARE‐reconstituted vesicles was determined to be ∼10 s, which is two orders of magnitude faster than in its absence. Calcium acts downstream of SNAREs, since the presence of SNAREs in bilayers increases the potency of calcium‐induced vesicle fusion, without significantly influencing its efficacy. Hence, this study suggests that in the physiological state in cells, both SNAREs and calcium operate as the minimal fusion machinery.
N‐terminal pro‐brain natriuretic peptide for discriminating between cardiac and non‐cardiac dyspnoea
Authors: Nielsen Lene Svendstrup , Svanegaard Jens , Klitgaard Niels Anders , Egeblad Henrik 
Published: December 2003

AbstractAim:Evaluation of N‐terminal pro‐brain natriuretic peptide (NT‐proBNP) to confirm or disprove heart failure in community patients complaining of dyspnoea.Methods and results:General practitioners referred 345 consecutive patients complaining of dyspnoea to our hospital‐based clinic, where a diagnosis was established based on a combined programme for heart and lung diseases including echocardiography. The level of NT‐proBNP in plasma was also measured. The mean (S.D.) concentration of NT‐proBNP in patients with heart failure was significantly higher, 189 (270) pmol/l in patients with heart failure (n=81), than in patients with non‐cardiac dyspnoea (n=264), 17 (38) pmol/l (P<0.001). In patients ≥50 years NT‐proBNP <11 pmol/l for men and <17 pmol/l for women excluded heart failure with a negative predictive value of 97% while the positive predictive value was 53%, the sensitivity 95% and the specificity 68%. Areas under receiver operator characteristic curves for men and women were 0.93 and 0.90, respectively.Conclusion:In a relevant setting of primary care patients complaining of dyspnoea, NT‐proBNP seems promising for disproval of heart failure, and this test may reduce the need for echocardiographic screening with 50%. However, the discrimination levels of NT‐proBNP found in this study may need prospective confirmation, before the test can be generally recommended.
Transcardiac increase in tumor necrosis factor‐α and left ventricular end‐diastolic volume in patients with dilated cardiomyopathy
Authors: Tsutamoto Takayoshi , Wada Atsuyuki , Ohnishi Masato , Tsutsui Takashi , Ishii Chitose , Ohno Keijin , Fujii Masanori , Matsumoto Takehiro , Yamamoto Takashi , Takayama Tomoyuki , Dohke Tomohiro , Horie Minoru 
Published: December 2003

AbstractBackground:It remains unclear whether tumor necrosis factor (TNF)‐α and interleukin‐6 (IL‐6) are secreted from the failing heart and whether there is a relationship between the transcardiac gradients of these cytokines and left ventricular (LV) remodeling.Aims:This study evaluated the relationship between transcardiac gradients of cytokines and LV volume and function in congestive heart failure patients with dilated cardiomyopathy (DCM).Methods and results:We measured the plasma levels of TNF‐α and IL‐6 in the aortic root (Ao) and the coronary sinus (CS) in 60 patients with DCM. There was no difference in plasma IL‐6 between the Ao and the CS. However, the plasma TNF‐α level was significantly higher in the CS than that in the Ao. There was a significant correlation between the transcardiac gradient of plasma TNF‐α and the LV end‐diastolic volume index (LVEDVI) and LV ejection fraction. According to stepwise multivariate analyses, the transcardiac increase of TNF‐α showed an independent and significantly positive relationship with a large LVEDVI.Conclusions:These results indicate that the elevated plasma TNF‐α is partly derived from the failing heart in patients with DCM and that TNF‐α plays a potential role in structural LV remodeling in patients with DCM.