bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simple parameterization of non‐proteinogenic amino acids for QSAR of antibacterial peptides
Authors: Lejon Tore , Svendsen John S. , Haug Bengt E. 
Published: September 2002

AbstractThe antibacterial activity of bovine lactoferricin‐(17–31)‐pentadecapeptide against Escherichia coli and Staphylococcus aureus is sensitive to substitution of the Trp residues, and synthetic peptides with phenylalanine and any of eight non‐proteinogenic aromatic amino acids greatly affected antibiotic activity. Using simple size‐related descriptors for the new amino acids it is possible to develop quantitative structure–activity relationships (QSARs) that can be used as tools in the search for more active peptides. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.
Synthesis of a 2‐arylsulphonylated tryptophan: the antibacterial activity of bovine lactoferricin peptides containing Trp(2‐Pmc)
Authors: Haug Bengt Erik , Andersen Jill , Rekdal Øystein , Svendsen John S. 
Published: September 2002

AbstractA modified tryptophan, β‐[2‐(2,2,5,7,8‐pentamethylchroman‐6‐sulphonyl)‐indol‐3‐yl]alanine, Trp(2 − Pmc) = Tpc has been synthesized. Replacement of tryptophan in a bovine lactoferricin model peptide with the modified tryptophan resulted in peptides with a substantially increased antibacterial activity against Escherichia coli and Staphylococcus aureus. The most active peptides against each bacterial strain displayed minimal inhibitory concentrations of 7.5 μg/ml. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.
A note on stochastically acceptable quality
Authors: Finkelstein Max S. 
Published: September 2002

AbstractA random variable of quality, characterized by the quality distribution function, is considered both for continuous and discrete cases. The acceptable quality distribution function is introduced and different types of stochastic comparison are discussed: comparison in the mean, ordering in distribution, variability ordering and hazard‐rate ordering. Acceptable, unacceptable and intermediate regions for levels of quality are determined by the discretization procedure. It is assumed that the quality of a product is revealed through usage. A simple reliability setting is considered when the quality of a product is directly dependent on its reliability characteristics in usage. Possible generalizations are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Performance of customized control charts to detect process disturbances
Authors: Heredia‐Langner Alejandro , Montgomery Douglas C. , Runger George C. , Borror Connie M. , Post Richard I. 
Published: September 2002

AbstractIn this paper we demonstrate the use of control charts based on orthogonal contrasts for a semiconductor manufacturing process. The statistical performance of individuals control charts based on these contrasts and their exponentially weighted moving average counterparts is compared to that of the traditional approach. Contrast‐based charts have superior detection capabilities than the traditional approach when targeted at specific process disturbances. Copyright © 2001 John Wiley & Sons, Ltd.
A Monte Carlo comparison of capability indices when processes are non‐normally distributed
Authors: Wu Hsin‐Hung , Swain James J. 
Published: September 2002

AbstractProcess capability indices are widely used to quantify the ability of a process to produce results on target and within specification limits. The most commonly seen capability indices assume that measurements are taken from normally distributed populations. However, such normality‐based capability indices are very sensitive to departures from normality. Therefore, another non‐normality‐based indices based on the weighted variance method have been developed to deal with non‐normal processes in this paper. Also, a comparison among the Clements, the Johnson–Kotz–Pearn, and the weighted variance methods has been conducted by considering the Johnson family of distributions to generate non‐normal distributions systematically. The results show that the Clements method becomes misleading when the underlying distribution is skewed. On the other hand, the performance of the Johnson–Kotz–Pearn method is far from the nominal values except for the log–normal cases with smaller values of kurtosis. On the other hand, the weighted variance method is the best estimator to estimate the nominal values in unbounded and log–normal cases for different combinations of skewness and kurtosis. It is concluded that the weighted variance method is the best among the three estimators, especially when the underlying distribution belongs to the log–normal and unbounded distributions of the Johnson family. Copyright © 2001 John Wiley & Sons, Ltd.
Comparison of two new approaches to variable ordering for binary decision diagrams
Authors: Bartlett L. M. , Andrews J. D. 
Published: September 2002

AbstractFault tree analysis, FTA, is one of the most commonly used techniques for safety system analysis. There can be problems with the efficiency and accuracy of the approach when dealing with large tree structures. Recently the binary decision diagram (BDD) methodology has been introduced which significantly aids the analysis of the fault tree diagram. The approach has been shown to improve both the efficiency of determining the minimal cut sets of the fault tree, and also the accuracy of the calculation procedure used to quantify the top event parameters.To utilize the BDD technique the fault tree structure needs to be converted into the BDD format. Converting the fault tree is relatively straightforward but requires the basic events of the tree to be placed in an ordering. The ordering of the basic events is critical to the resulting size of the BDD, and ultimately affects the performance and benefits of this technique. There are a number of variable ordering heuristics in the literature, however the performance of each depends on the tree structure being analysed. These heuristic approaches do not yield a minimal BDD structure for all trees, some approaches generate orderings that are better for some trees but worse for others.Within this paper two approaches to the variable ordering problem have been discussed. The first is the pattern recognition approach of neural networks, which is used to select the best ordering heuristic for a given fault tree from a set of alternatives. The second examines a completely new heuristic approach of using the structural importance of a component to produce a ranked ordering. The merits of each are discussed and the results compared. Copyright © 2001 John Wiley & Sons, Ltd.
Managing the uncertainties of software testing: a Bayesian approach
Authors: Rees Kearton , Coolen Frank , Goldstein Michael , Wooff David 
Published: September 2002

AbstractTesting of software systems involves many complex problems for test managers. Important issues to be considered include how to quantify reliability, how to design tests, which tests should be performed given time, cost and resource constraints, what are the implications of test failures, what tests should be re‐run following corrections to rectify faults, and so forth. All of these issues are related to the uncertainties involved in the quality of the software and the process of testing. In a continuing collaboration, the use of Bayesian graphical models has been explored to model these uncertainties and to support software testers and test managers with their complex tasks.This paper discusses some features of Bayesian graphical models which are pertinent to modelling software testing problems, and in particular the kind of support they can provide to test managers and the use of such models in a practical environment. Details of the modelling process are presented elsewhere. Copyright © 2001 John Wiley & Sons, Ltd.
Short pulse laser mass spectrometry of nitrotoluenes: ionization and fragmentation behavior
Authors: Weickhardt Christian , Tönnies Karen 
Published: September 2002

AbstractThe mass spectra of all isomers of mononitrotoluene, four isomers of dinitrotoluene and of 2,4,6,‐trinitrotoluene, obtained by multiphoton ionization utilizing ultrashort laser pulses with center wavelengths of either 206 nm or 412 nm, are presented and discussed. Under these ionization conditions all nitrotoluenes exhibit a high degree of fragmentation which increases with the degree of substitution. For the compounds having a nitro group in position 2 and/or 6 a pronounced ortho effect leading to the loss of OH is observed. The fragmentation patterns in the lower mass range are typical for alkylated aromatic substances. While no fundamental differences between the mass spectra obtained with the two wavelengths were observed, the visible light in all cases resulted in a broader variety of fragments and additional signals in the higher mass range. The latter can be used for isomer identification. Copyright © 2002 John Wiley & Sons, Ltd.
Enantiomeric separation and quantification of fluoxetine (Prozac®) in human plasma by liquid chromatography/tandem mass spectrometry using liquid‐liquid extraction in 96‐well plate format
Authors: Shen Zhongzhou , Wang Sui , Bakhtiar Ray 
Published: September 2002

AbstractFluoxetine (Prozac®) is currently one of the widely prescribed selective serotonin reuptake inhibitors (SSRIs) for the treatment of depression. A high‐throughput sample preparation procedure using liquid‐liquid extraction (LLE) in a 96‐well plate format in conjunction with liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed and validated for quantification of fluoxetine enantiomers in human plasma. After addition of internal standard and ammonium hydroxide, samples were extracted with ethyl acetate. The organic extract was evaporated to dryness and reconstituted in methanol. Where possible, sample transfer and LLE steps were automated using a Tomtec Quadra 96 workstation. Adequate separation of fluoxetine enantiomeric pairs (resolution of 1.17) was achieved on a vancomycin column eluted with methanol containing 0.075% (by weight) ammonium trifluoroacetate. A triple quadrupole mass spectrometer, operated in the multiple reaction monitoring mode at m/z 310 → 44 for fluoxetine enantiomeric pairs and m/z 287 → 241 for oxazepam (internal standard), was used. Analysis was performed in the positive ion mode using atmospheric pressure chemical ionization (APCI). The standard curve range was 2.0–1000 ng/mL for each fluoxetine enantiomer. The intra‐ and inter‐day precision and accuracy of the quality control (QC) samples were <12.5% (CV) and <13.6% (CV), respectively, for each fluoxetine enantiomer; the correlation coefficient was >0.990. Method ruggedness was demonstrated by the reproducible performance of the assay during a 3‐day validation period. Copyright © 2002 John Wiley & Sons, Ltd.
Urinary 19‐norandrosterone purification by immunoaffinity chromatography: application to gas chromatography/combustion/isotope ratio mass spectrometric analysis
Authors: Desroches M. C. , Mathurin J. C. , Richard Y. , Delahaut P. , de Ceaurriz J. 
Published: September 2002

AbstractThe detection of exogenous 19‐norandrosterone (19‐NA) in urines was investigated by using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). 19‐NA is, for the first time to our knowledge, isolated from urinary matrix by specific immunoaffinity chomatography (IAC) before analysis. The sample preparation consisted of a preliminary purification of urine by solid‐phase extraction after hydrolysis by β‐glucuronidase. Unconjugated 19‐NA was thus isolated by IAC and directly analysed by GC/C/IRMS. Optimisation of IAC purification was achieved and the reliability of the technique for anti‐doping control is discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Atmospheric pressure chemical ionisation liquid chromatography/mass spectrometry of bacteriochlorophylls from Chlorobiaceae: characteristic fragmentations
Authors: Airs Ruth L. , Keely Brendan J. 
Published: September 2002

AbstractAtmospheric pressure chemical ionisation liquid chromatography/mass spectrometry/mass spectrometry (APCI‐LC/MS/MS) has been applied to the study of bacteriochlorophylls c, d, and e of phototrophic prokaryotes. Cultures of Chlorobiaceae containing bacteriochlorophyll c, d or e were examined using a high‐resolution high‐performance liquid chromatography (HPLC) method and APCI‐LC/MS/MS employing post‐column addition of formic acid. The results reveal complex distributions of bacteriochlorophyll homologues, with some closely eluting species giving isobaric protonated molecules. On‐line LC/MS/MS studies reveal characteristic fragment ions for bacteriochlorophylls c, d, and e. Fragmentations involving loss of the extended alkyl substituents that are unique to bacteriochlorophylls c, d and e and their derivatives have been rationalised by studying the phaeophorbides and the results applied to the direct study of the bacteriochlorophylls. Copyright © 2002 John Wiley & Sons, Ltd.
A method to identify and simultaneously determine the relative quantities of proteins isolated by gel electrophoresis
Authors: Sechi Salvatore 
Published: September 2002

AbstractGel electrophoresis is often used for the primary analysis and purification of proteins, and peptide mapping by matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) is a widely used technique for the rapid identification of unknown proteins. The identification is usually obtained by digesting the protein with an enzyme and matching the masses of the proteolytic peptides with those of each protein in a sequence database. Another important aspect in many proteomic experiments is the determination of the relative protein quantities (e.g. comparison between control and altered states). Usually, this is obtained by comparing the spot intensities of two independent gels. This procedure is time‐consuming and not very accurate. Recently, several methodologies using isotope labeling of proteins for quantitative proteomic studies have been introduced (e.g. using ICAT reagents or growing cells in isotopically enriched nutrients). However, none of these methodologies is foolproof and there is still the need for simple and inexpensive alternatives for determining the relative quantities of proteins. Previously, we showed that a mixture of acrylamide and deuterated acrylamide could be used as cysteine alkylating reagent prior to electrophoresis, improving the coverage and the confidence of the protein identification procedure (Sechi S, Chait BT. Anal. Chem. 1998; 70: 5150). Here we show that a similar approach can be used to obtain relative quantitation at the femtomole level of proteins isolated by gel electrophoresis. Deuterated acrylamide is used to alkylate the cysteines in one sample and regular acrylamide is used to alkylate the cysteines in the second sample. The two samples are then mixed together in a 1:1 ratio and the relative protein quantities are determined from the ion intensity ratios of the two cysteine‐containing peptides isotopic envelopes (regular/deuterated). The analysis of several proteins mixed in different ratios is reported showing that this approach can reliably be used for protein identification and quantification. Briefly, a simple and inexpensive method for quantifying and simultaneously identifying proteins isolated by gel electrophoresis using MALDI‐MS is presented. Published in 2002 by John Wiley & Sons, Ltd.
Determination of total urinary mercury by on‐line sample microwave digestion followed by flow injection cold vapour inductively coupled plasma mass spectrometry or atomic absorption spectrometry
Authors: Bettinelli M. , Spezia S. , Ronchi A. , Minoia C. 
Published: September 2002

AbstractThe total mercury content in urine was determined by inductively coupled plasma mass spectrometry with the so‐called cold vapour method after on‐line oxidative treatment of the sample in a microwave oven (FI‐MW‐CV‐ICPMS). Use of a KBr/KBrO3 mixture, microwave digestion, and the final oxidation with KMnO4, assure the complete recovery of the organic forms of Hg which would be difficult to determine otherwise if using only the CV‐ICPMS apparatus. Quantitative recoveries were obtained for phenyl Hg chloride (PMC), dimethyl Hg (DMM), Hg acetate (MA) and methyl Hg chloride (MMC). Use of automatic flow injection microwave systems (FI‐MW) for sample treatment reduces environmental contamination and allows detection limits suitable for the determination of reference values. Since no certified reference materials were commercially available in the concentration ranges of interest, the accuracy of the proposed procedure has been assessed by analysing a series of urine samples with two independent techniques, ICP‐MS and AAS. When using the FI‐MW‐CV‐ICP‐MS technique, the detection limit was assessed at 0.03µg/L Hg, while with FI‐MW‐CV‐AAS it was 0.2µg/L Hg. The precision of the method was less than 2–3% for FI‐MW‐CV‐ICP‐MS and about 3–5% for FI‐MV‐CV‐AAS at concentrations below 1µg/L Hg. These results show that ICP‐MS can be considered as a “reference technique” for the determination of total urinary Hg at very low concentrations, such as are present in non‐exposed subjects. Copyright © 2002 John Wiley & Sons, Ltd.
CMV and blood transfusions
Authors: Roback John D. 
Published: September 2002

AbstractAmong the human herpesviruses, cytomegalovirus (CMV) is the only one that has assumed significant importance in blood transfusion. Transfusion transmission of CMV (TT‐CMV) to seronegative immunocompromised patients can lead to lethal CMV disease. Studies over the past 30 years have demonstrated that monocytes latently infected with CMV represent the primary vector for TT‐CMV, and that TT‐CMV can be largely abrogated by transfusing at‐risk patients with either seronegative units or blood filtered to remove white blood cells. However, the small number of cases of breakthrough TT‐CMV that follow transfusion of either seronegative or filtered blood still produce morbidity and mortality. These circumstances have motivated ongoing efforts to provide improved protection from TT‐CMV, including the use of CMV DNA amplification for blood screening, and pathogen inactivation to sterilise all blood components prior to transfusion. Copyright © 2002 John Wiley & Sons, Ltd.
Some results in nonlinear QFT
Authors: Baños A. , Bailey F. N. , Montoya F. J. 
Published: September 2002

AbstractNonlinear QFT (quantitative feedback theory) is a technique for solving the problem of robust control of an uncertain nonlinear plant by replacing the uncertain nonlinear plant with an ‘equivalent’ family of linear plants. The problem is then finding a linear QFT controller for this family of linear plants. While this approach is clearly limited, it follows in a long tradition of linearization approaches to nonlinear control (describing functions, extended linearization, etc.) which have been found to be quite effective in a wide range of applications. In recent work, the authors have developed an alternative function space method for the derivation and validation of nonlinear QFT that has clarified and simplified several important features of this approach. In particular, single validation conditions are identified for evaluating the linear equivalent family, and as a result, the nonlinear QFT problem is reduced to a linear equivalent problem decoupled from the linear QFT formalism. In this paper, we review this earlier work and use it in the development of (1) new results on the existence of nonlinear QFT solutions to robust control problems, and (2) new techniques for the circumvention of problems encountered in the application of this approach. Copyright © 2001 John Wiley & Sons, Ltd.
Adaptive output feedback tracking control of spacecraft formation
Authors: Wong Hong , Kapila Vikram , Sparks Andrew G. 
Published: September 2002

AbstractIn this paper, an adaptive, output feedback control design methodology is presented for a spacecraft formation flying (SFF) system. A Lagrangian derivation of the SFF model is considered to produce position dynamics for follower spacecraft #nrelative to follower spacecraft #(n−1), wherenis an arbitrary positive integer, assuming that the leader spacecraft in the formation follows a no‐thrust, natural, elliptical orbit. Next, a control law is designed to provide a filtered velocity measurement and a desired adaptive compensation with semi‐global, asymptotic, relative position tracking. To show the efficacy of the control algorithm, all desired trajectories are generated online by numerically solving the unperturbed nonlinear SFF dynamics with initial conditions satisfying a no‐thrust, natural orbit constraint equation. The proposed control law is simulated for the case of two and three spacecraft and is shown to yield semi‐global, asymptotic tracking of the relative position in addition to the convergence of disturbance parameter estimates. Copyright © 2002 John Wiley & Sons, Ltd.
Fuel optimal manoeuvres for multiple spacecraft formation reconfiguration using multi‐agent optimization
Authors: Yang Guang , Yang Qingsong , Kapila Vikram , Palmer Daniel , Vaidyanathan Ravi 
Published: September 2002

AbstractThe Air Force Research Laboratory has identified multiple spacecraft formation flying as an enabling technology for several future space missions. A key benefit of formation flying is the ability to reconfigure the spacecraft formation to achieve different mission objectives. In this paper, generation of fuel optimal manoeuvres for spacecraft formation reconfiguration is modelled and analysed as a multi‐agent optimal control problem. Multi‐agent optimal control is quite different from the traditional optimal control for single agent. Specifically, in addition to fuel optimization for a single agent, multi‐agent optimal control necessitates consideration of task assignment among agents for terminal targets in the optimization process. In this paper, we develop an efficient hybrid optimization algorithm to address such a problem. The proposed multi‐agent optimal control methodology uses calculus of variation, task assignment, and parameter optimization at different stages of the optimization process. This optimization algorithm employs a distributed computational architecture. In addition, the task assignment algorithm, which guarantees the global optimal assignment of agents, is constructed using the celebrated principle of optimality from dynamic programming. A communication protocol is developed to facilitate decentralized decision making among agents. Simulation results are included to illustrate the efficacy of the proposed multi‐agent optimal control algorithm for fuel optimal spacecraft formation reconfiguration. Copyright © 2002 John Wiley & Sons, Ltd.
Property testers for dense constraint satisfaction programs on finite domains
Authors: Andersson Gunnar , Engebretsen Lars 
Published: September 2002

AbstractMany NP‐hard languages can be “decided” in subexponential time if the definition of “decide” is relaxed only slightly. Rubinfeld and Sudan introduced the notion of property testers, probabilistic algorithms that can decide, with high probability, if a function has a certain property or if it is far from any function having this property. Goldreich, Goldwasser, and Ron constructed property testers with constant query complexity for dense instances of a large class of graph problems. Since many graph problems can be viewed as special cases of the Constraint Satisfaction Problem on Boolean domains, it is natural to try to construct property testers for more general cases of the Constraint Satisfaction Problem. In this paper, we give explicit constructions of property testers using a constant number of queries for dense instances of Constraint Satisfaction Problems where the constraints have constant arity and the variables assume values in some domain of finite size. © 2002 Wiley Periodicals, Inc. Random Struct. Alg., 21: 14–32, 2002
Asymptotic analysis of (3, 2, 1)‐shell sort
Authors: Smythe R.T. , Wellner J.A. 
Published: September 2002

AbstractWe analyze the (3, 2, 1)‐Shell Sort algorithm under the usual random permutation model. © 2002 Wiley Periodicals, Inc. Random Struct. Alg., 21: 59–75, 2002