bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution of indel lengths
Authors: Qian Bin , Goldstein Richard A.
Published: August 2002

Protein sequence alignment has become a widely used method in the study of newly sequenced proteins. Most sequence alignment methods use an affine gap penalty to assign scores to insertions and deletions. Although affine gap penalties represent the relative ease of extending a gap compared with initializing a gap, it is still an obvious oversimplification of the real processes that occur during sequence evolution. To improve the efficiency of sequence alignment methods and to obtain a better understanding of the process of sequence evolution, we wanted to find a more accurate model of insertions and deletions in homologous proteins. In this work, we extract the probability of a gap occurrence and the resulting gap length distribution in distantly related proteins (sequence identity < 25%) using alignments based on their common structures. We observe a distribution of gaps that can be fitted with a multiexponential with four distinct components. The results suggest new approaches to modeling insertions and deletions in sequence alignments. Proteins 2001;45:102–104. © 2001 Wiley‐Liss, Inc.
Structure of rat parvalbumin with deleted AB domain: Implications for the evolution of EF hand calcium‐binding proteins and possible physiological relevance
Authors: Thépaut Michel , Strub Marie‐Paule , Cavé Adrien , Banères Jean‐Louis , Berchtold Martin W. , Dumas Christian , Padilla André
Published: August 2002

Among the EF‐hand Ca2+‐binding proteins, parvalbumin (PV) and calbindin D9k (CaB) have the function of Ca2+ buffers. They evolved from an ancestor protein through two phylogenetic pathways, keeping one pair of EF‐hands. They differ by the extra helix–loop–helix (AB domain) found in PV and by the linker between the binding sites. To investigate whether the deletion of AB in PV restores a CaB‐like structure, we prepared and solved the structure of the truncated rat PV (PVratΔ37) by X‐ray and NMR. PVratΔ37 keeps the PV fold, but is more compact, having a well‐structured linker, which differs remarkably from CaB. PvratΔ37 has no stable apo‐form, has lower affinity for Ca2+ than full‐length PV, and does not bind Mg2+, in contrast to CaB. Structural differences of the hydrophobic core are partially responsible for lowering the calcium‐binding affinity of the truncated protein. It can be concluded that the AB domain, like the linker of CaB, plays a role in structural stabilization. The AB domain of PV protects the hydrophobic core, and is required to maintain high affinity for divalent cation binding. Therefore, the AB domain possibly modulates PV buffer function. PVratΔ37 (Type PDB; Value 1G33; Service) Proteins 2001;45:117–128. © 2001 Wiley‐Liss, Inc.
Conserved core structure and active site residues in alkaline phosphatase superfamily enzymes
Authors: Galperin Michael Y. , Jedrzejas Mark J.
Published: August 2002

Cofactor‐independent phosphoglycerate mutase (iPGM) has been previously identified as a member of the alkaline phosphatase (AlkP) superfamily of enzymes, based on the conservation of the predicted metal‐binding residues. Structural alignment of iPGM with AlkP and cerebroside sulfatase confirmed that all these enzymes have a common core structure and revealed similarly located conserved Ser (in iPGM and AlkP) or Cys (in sulfatases) residues in their active sites. In AlkP, this Ser residue is phosphorylated during catalysis, whereas in sulfatases the active site Cys residues are modified to formylglycine and sulfatated. Similarly located Thr residue forms a phosphoenzyme intermediate in one more enzyme of the AlkP superfamily, alkaline phosphodiesterase/nucleotide pyrophosphatase PC‐1 (autotaxin). Using structure‐based sequence alignment, we identified homologous Ser, Thr, or Cys residues in other enzymes of the AlkP superfamily, such as phosphopentomutase, phosphoglycerol transferase, phosphonoacetate hydrolase, and GPI‐anchoring enzymes (glycosylphosphatidylinositol phosphoethanolamine transferases) MCD4, GPI7, and GPI13. We predict that catalytical cycles of all the enzymes of AlkP superfamily include phosphoenzyme (or sulfoenzyme) intermediates. Proteins 2001;45:318–324. © 2001 Wiley‐Liss, Inc.
Speeding protein folding beyond the Gō model: How a little frustration sometimes helps
Authors: Plotkin Steven S.
Published: August 2002

By perturbing a Gō model toward a realistic protein Hamiltonian by adding non‐native interactions, we find that the folding rate is in general enhanced as ruggedness is initially increased, as long as the protein is sufficiently large and flexible. Eventually, the rate drops rapidly toward zero when ruggedness significantly slows conformational transitions. Energy landscape arguments for thermodynamics and kinetics are coupled with a treatment of non‐native collapse to elucidate this effect. Proteins 2001;45:337–345. © 2001 Wiley‐Liss, Inc.
Fumigant toxicity of volatile natural products from Korean spices and medicinal plants towards the rice weevil, Sitophilus oryzae (L)
Authors: Lee Sung‐Eun , Lee Byoung‐Ho , Choi Won‐Sik , Park Byeoung‐Soo , Kim Jeong‐Gyu , Campbell Bruce C
Published: August 2002

The fumigant toxicity of various volatile constituents of essential oils extracted from sixteen Korean spices and medicinal plants towards the rice weevil, Sitophilus oryzae L (Coleoptera: Curculionidae), was determined. The most potent toxicity was found in the essential oil from Mentha arvensis L var piperascens (LC50 = 45.5 µl litre−1 air). GC–MS analysis of essential oil from M arvensis showed it to be rich in menthol (63.2%), menthone (13.1%) and limonene (1.5%), followed in abundance by β‐pinene (0.7%), α‐pinene (0.6%) and linalool (0.2%). Treatment of S oryzae with each of these terpenes showed menthone to be most active (LC50 = 12.7 µl litre−1 air) followed by linalool (LC50 = 39.2 µl litre−1 air) and α‐pinene (LC50 = 54.9 µl litre−1 air). Studies on inhibition of acetylcholinesterase activity of S oryzae showed menthone to have a nine‐fold lower inhibitory effect than menthol, despite menthone being 8.1‐fold more toxic than menthol to the rice weevil. Different modes of toxicity of these monoterpenes towards S oryzae are discussed.

© 2001 Society of Chemical Industry
A mechanistic analysis of penetration of glyphosate salts across astomatous cuticular membranes
Authors: Schönherr Jörg
Published: August 2002

Penetration of glyphosate salts across isolated poplar (Populus canescens (Aiton) Sm) cuticular membranes (CM) was studied using Na+, K+, NH4+, trimethylsulfonium+ (TMS) and isopropylamine+ (IPA) as cations. After droplet drying, humidity over the salt residues on the outer surfaces of the CM was kept constant, and cuticular penetration was monitored by sampling the receiver solution facing the inner surfaces of the CM. Glyphosate salts disappeared exponentially with time from the surfaces of the CM. This first‐order process could be quantitatively described using rate constants (k) or half‐times (time for 50% penetration; t1/2). Humidity strongly affected the velocity of penetration, as k increased by factors of 5.3 (K‐glyphosate), 6.9 (TMS‐glyphosate), 7.1 (NH4‐glyphosate), 8.5 (Na‐glyphosate) and 10.5 (IPA‐glyphosate) when humidity was increased from 70 to 100%. Depending on the type of cation and humidity, t1/2 varied between 4 and 70 h, but the humidity effect was statistically significant only at 100% humidity, when half‐times were highest with IPA‐glyphosate and lowest with TMS‐glyphosate. Glyphosate acid penetration was measured only at 90% humidity and found to be extremely slow (t1/2 = 866 h). Adding 0.2 g litre−1 of a wetter (alkylpolyglucoside) to the donor increased IPA‐glyphosate rate constants by about four times, but increasing concentration produced no further increase in k. When donors contained 0.2 g litre−1 wetter, further additions of 4 g litre−1 Ethomeen T25 did not change rate constants measured with IPA‐glyphosate at 90% humidity, while Genapol C‐100 and diethyl suberate increased k by only 35%. Concentration of IPA‐glyphosate (1, 2 and 4 g litre−1) did not influence k at 90% humidity, and pH of donor solutions (4.0, 7.7, 9.5) had no effect on k of K‐glyphosate at 90% humidity. Temperature (10 to 25 °C) had only a small influence on velocity of penetration of IPA‐glyphosate and K‐glyphosate, as energies of activation amounted to only 4.26 and 2.92 kJ mole−1, respectively. These results are interpreted as evidence for penetration of glyphosate salts in aqueous pores.

© 2002 Society of Chemical Industry
Sea louse control in Scotland, past and present
Authors: Rae Gordon H
Published: August 2002

Methods for farming the Atlantic salmon (Salmo salar L) in Scotland were developed at the Unilever Research Laboratory facility at Lochailort on the west coast of Scotland in the late 1960s. By the spring of 1972 a fledgling commercial company had been set up and Marine Harvest, as it was known, received its first year class of smolts at Lochailort. Sea lice (Lepeophtheirus salmonis Krøyer) from passing wild fish infected the smolts but did not cause any significant damage until the summer of 1976 when intervention was required. The Scottish industry has since grown to become a vital source of employment for fragile rural economies and produced about 130 000 tonnes of salmon in 2000. This paper gives an overview of how fish welfare has been maintained by the development of treatments and management strategies aimed at minimising the impact of sea lice.

© 2002 Society of Chemical Industry
Synthesis of a membrane protein with two transmembrane regions
Authors: Sato Takeshi , Kawakami Toru , Akaji Kenichi , Konishi Hiroki , Mochizuki Koji , Fujiwara Toshimichi , Akutsu Hideo , Aimoto Saburo
Published: August 2002

A membrane protein with two transmembrane domains was synthesized by means of the thioester method. The F1F0 ATP synthase subunit c (Sub.c), which consists of 79 amino acid residues (MW 8257), was chosen as a target. For synthetic purposes, two building blocks, Boc‐[Lys34(Boc)]‐Sub.c(1‐38)‐SCH2CH2CO‐Ala and Sub.c(39‐79), were synthesized via solid‐phase methods using Boc chemistry. RP‐HPLC purification conditions for the transmembrane peptide were examined. As a result, a combination of a mixture of formic acid, 1‐propanol and water with a phenyl column was found to be useful for separating the transmembrane peptide. The purified building blocks were condensed in DMSO in the presence of silver chloride, 3,4‐dihydro‐3‐hydroxy‐4‐oxo‐1,2,3‐benzotriazine (HOOBt), N,N‐diisopropylethylamine to give the product, Sub.c, after removal of Boc groups (yield 16%). The yield of the condensation reaction could be improved to 23% by raising the reaction temperature to 50 °C, and to 26% when a mixture of chloroform and methanol was used as a solvent. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.
Design of structural joints in building frames
Authors: Jaspart Jean‐Pierre
Published: August 2002

A single and unified concept for the design of structural joints in building frames made of any material has been developed in recent years, and is now widely implemented in European design codes. In the present paper, this concept is presented, its merits as far as the economy of a project are demonstrated, and practical design tools for its application in daily practice are briefly described. The paper also contains references to user's manuals and design handbooks.
The antioxidant activity of standardized extract of Ginkgo biloba (EGb 761) in rats
Authors: Bridi R. , Crossetti F. P. , Steffen V. M. , Henriques A. T.
Published: August 2002

The standardized extract of Ginkgo biloba (EGb 761) has been widely employed for its significant benefit in neurodegenerative disorders. Although antioxidative actions have been attributed to this extract, the mechanisms of the multiple principles involved in this pharmacological activity are not completely established. Parkinson's and Alzheimer's diseases are frequently associated with oxidative stress and defects in the cellular protective mechanisms. In this study, the lipid peroxidation (LPO) and the activity of the antioxidant enzymes, catalase (CAT) and superoxide dismutase (SOD) were evaluated in the hippocampus, striatum and substantia nigra (SN) of rats treated with EGb 761. An increase in the CAT and SOD activities in the hippocampus, striatum and SN, and a decrease of the LPO in the hippocampus were observed. These data are additional to the antioxidant properties of EGb 761 reported in the literature and indicate a possible role for the extract in the treatment of diseases involving free radicals and oxidative damage. Copyright © 2001 John Wiley & Sons, Ltd.
Protective effect of a plant formula on ethanol‐induced gastric lesions in rats
Authors: Zhu Min , Lew Katherine T. , Leung Po‐lau
Published: August 2002

A plant formula and its five components were evaluated independently for their gastric protective effect against ethanol‐induced stomach lesions in rats. Aqueous extracts of the plant formula (0.25–2 g crude drug/kg orally) and its individual components (at the same dose) all showed significant stomach protective effects dose dependently. However, when these extracts were given to rats at a dose of 0.25 g/kg, the five single‐herb preparations did not show any activity, but the formula‐extract still exhibited a strong protective effect. These findings suggest the presence of a synergistic effect among the plant components. Chemical examination of the extracts indicated that the major ingredients of the five plants were essential oils, terpenoids, flavonoids, glycosides and saccharides and these may contribute to the stomach protective activity observed. Copyright © 2002 John Wiley & Sons, Ltd.
The effect of Momordica charantia and Mucuna pruriens in experimental diabetes and their effect on key metabolic enzymes involved in carbohydrate metabolism
Authors: Rathi S. S. , Grover J. K. , Vats V.
Published: August 2002

The Indian traditional system of medicine prescribed traditional plant therapies. Two such plants, i.e. Momordica charantia (MC) and Mucuna pruriens (MP), earlier shown to reduce hyperglycaemia, were assessed for their anti hyperglycaemic effect on varying degrees of hyperglycaemia and diabetic complications. Alcohol and aqueous extracts of MC (50, 100 and 200 mg/kg/day) and only an alcohol extract of MP (100, 200 and 400 mg/kg/day) were evaluated in a pilot study (plasma glucose >180 mg/dL, 21 days), a chronic study in alloxanized rats (plasma glucose >280 mg/dL, 120 days) and streptozotocin (STZ) mice (plasma glucose >400 mg/dL, 60 days). In the pilot study, the maximum antihyperglycaemic effect occurred with an aqueous extract of MC at week 3 and an alcohol extract of MP at week 6 at a dose of 200 mg/kg/day. In chronic alloxanized rats, the selected dose of MC led to a significant fall of 64.33%, 66.96%, 69.7% and 70.53% in plasma glucose levels at 1, 2, 3 and 4 months, respectively. MP showed a decrease of 40.71%, 45.63%, 50.33% and 51.01% at the same time period. In chronic STZ diabetic mice, MC led to a mean reduction of 15.37%, 18.68% and 22.86% in plasma glucose levels on days 40, 50 and 60 of sampling while MP had no significant effect. The alteration in hepatic and skeletal muscle glycogen content and hepatic glucokinase, hexokinase, glucose‐6‐phosphate and phosphofructokinase levels in diabetic mice were partially restored by MC but not by MP. The mechanism of action of MC and MP is discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Sedative and anticonvulsant activities of goodyerin, a flavonol glycoside from Goodyera schlechtendaliana
Authors: Du Xiao‐Ming , Sun Ning‐Yi , Takizawa Nanako , Guo Yong‐Tian , Shoyama Yukihiro
Published: August 2002

Goodyerin is a flavonol glycoside isolated from the whole plants of Goodyera schlechtendaliana which has been used as a substitute for the crude drug, Anoectochilus formosanus. The pharmacological properties of goodyerin were assayed for effects on spontaneous locomotor activity, on pentobarbital‐induced hypnosis, and on anticonvulsant activity against picrotoxin‐induced seizures in rodents. Goodyerin exhibited a significant and dose‐dependent sedative and anticonvulsant effect. Copyright © 2002 John Wiley & Sons, Ltd.
Effects of luteolin on the inhibition of proliferation and induction of apoptosis in human myeloid leukaemia cells
Authors: Ko W. G. , Kang T. H. , Lee S. J. , Kim Y. C. , Lee B. H.
Published: August 2002

Luteolin, a flavonoid isolated from the fruit of Vitex rotundifolia, has been examined with regard to the inhibition of proliferation and induction of apoptosis in human myeloid leukaemia HL‐60 cells. The concentration required for 50% inhibition of the growth after 96 h was 15 ± 1.1 μM. The mode of cell death induced by luteolin was found to be apoptosis, as judged by the morphologic alteration of the cells and by the detection of DNA fragmentation using agarose gel electrophoresis. The degree of apoptosis was quantified by a sandwich enzyme immunoassay and flow cytometric analysis. These results suggest that luteolin may be used as potential chemopreventive and chemotherapeutic agents. Copyright © 2002 John Wiley & Sons, Ltd.
Polysaccharides isolated from Echinacea purpurea herba cell cultures to counteract undesired effects of chemotherapy—a pilot study
Authors: Melchart Dieter , Clemm Christof , Weber Bernhard , Draczynski Thorsten , Worku Felege , Linde Klaus , Weidenhammer Wolfgang , Wagner Hildebert , Saller Reinhard
Published: August 2002

In an open prospective study with matched historical controls we aimed to evaluate whether a polysaccharide fraction isolated from the herb Echinacea purpurea could counteract the undesired effects of ­chemotherapy. Fifteen patients with advanced gastric cancer undergoing palliative chemotherapy with etoposide, leucovorin and 5‐fluorouracil (ELF) received for 10 days (beginning 3 days before chemotherapy) daily i.v. injections of 2 mg of a polysaccharide fraction isolated from Echinacea purpurea herb cell cultures (EPS‐EPO VIIa). The median number of leukocytes 14–16 days after chemotherapy was 3630/μL (range 1470–5770) in the patients receiving EPS‐EPO VIIa compared with 2370/μL (870–3950) in the patients of the historical control group (p = 0.015). EPS‐EPO VIIa had no clinically relevant effects on phagocytic activity of granulocytes or on lymphocyte subpopulations. Sixty‐eight adverse events including two deaths were observed, most likely due to chemotherapy and the general condition of the patients. However, an association with the test intervention cannot be ruled out completely. The results of this pilot study suggest that EPS‐EPO VIIa might be effective in reducing chemotherapy‐induced leukopenia. The efficacy and safety should be investigated in further studies. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of Mangifera indica L. extract (QF808) on protein and hepatic microsome peroxidation
Authors: Martínez Gregorio , Giuliani Attilia , León Olga Sonia , Pérez Gema , Núñez Selles Alberto J
Published: August 2002

The antioxidant activities of QF808, a steam bark extract of Mangifera indica L., were studied on hydroxyl‐mediated oxidation of bovine serum albumin (BSA) and in a hepatic microsome system. The extract was effective in reducing the oxidation of BSA, since its half‐ maximal inhibition concentration (IC50) was 0.0049% w/v in the inhibition of carbonyl group formation and lower than 0.0025% w/v in the inhibition of sulfhydryl group loss. QF808 inhibited lipid peroxidation which was initiated enzymatically by reduced nicotinamide adenine dinucleotide phosphate (NADPH), IC50= 0.00075% w/v, or non‐enzymatically by ascorbic acid, IC50 = 0.0126% w/v. The extract tested did not inhibit NADPH‐dependent cytochrome P‐450 reductase activity, since it had no effect on the oxidation rate of NADPH. These results suggest that QF808 has an antioxidant activity, probably due to its ability to scavenge free radicals involved in microsome lipid peroxidation. In addition, QF808 antioxidant profile in vitro is probably similar to its principal polyphenolic component, mangiferin, a glycosylated xanthone. Copyright © 2001 John Wiley & Sons, Ltd.
Efficacy and tolerability of a standardized willow bark extract in patients with osteoarthritis: randomized placebo‐controlled, double blind clinical trial
Authors: Schmid B , Lüdtke R , Selbmann H‐K , Kötter I , Tschirdewahn B , Schaffner W , Heide L
Published: August 2002

This study assessed the clinical efficacy of a chemically standardized willow bark extract in the treatment of osteoarthritis. Willow bark extract, in a dose corresponding to 240 mg salicin/day, was compared with placebo in a 2‐week, double‐blind, randomized controlled trial. The primary outcome measure was the pain dimension of the WOMAC Osteoarthritis Index. Secondary outcome measures included the stiffness and physical function dimensions of the WOMAC, daily visual analogue scales (VAS) on pain and physical function, and final overall assessments by both patients and investigators. A total of 78 patients (39 willow bark extract, 39 placebo) participated in the trial. A statistically significant difference between the active treatment and the placebo group was observed in the WOMAC pain dimension (d = 6.5 mm, 95% C.I. = 0.2–12.7 mm, p = 0.047); the WOMAC pain score was reduced by 14% from the baseline level after 2 weeks of active treatment, compared with an increase of 2% in the placebo group. The patient diary VAS confirmed this result, and likewise the final overall assessments showed superiority of the willow bark extract over the placebo (patients' assessment, p = 0.0002; investigators' assessment, p = 0.0073). It is concluded that the willow bark extract showed a moderate analgesic effect in osteoarthritis and appeared to be well tolerated. Copyright © 2001 John Wiley & Sons, Ltd.
Antimicrobial properties of star anise (Illicium verum Hook f)
Authors: De Minakshi , De Amit Krishna , Sen Parimal , Banerjee Arun Baran
Published: August 2002

Star anise (Illicium verum Hook f) has been shown to possess potent antimicrobial properties. Chemical studies indicate that a major portion of this antimicrobial property is due to anethole present in the dried fruit. Studies with isolated anethole (compared with standard anethole) indicated that it is effective against bacteria, yeast and fungal strains. Copyright © 2002 John Wiley & Sons, Ltd.
Immunomodulatory activity of septilin, a polyherbal preparation
Authors: Daswani B. R. , Yegnanarayan Radha
Published: August 2002

Septilin is a polyherbal preparation, claimed to be effective in conditions such as chronic stubborn URTI, tonsillitis, cutaneous infections, dental infections and also prescribed as a health supplement. In view of this, the present experimental study was undertaken to evaluate the effect of Septilin on different arms of the immune system. The experimental animals (male albino rats and mice) were divided into three groups. Group I received distilled water; group II received Septilin in a dose of 1 g/kg (rats) or 1.5 g/kg (mice); group III received Septilin 2 g/kg (rats) or 3 g/kg (mice) orally for 28 days. They were evaluated for immunological function on day 29 by studying weight gain, resistance against E. coli sepsis, haemogram, phagocytic activity of PMN cells and reticuloendothelial system, delayed hypersensitivity to oxazolone and the plaque forming cell response of splenic lymphocytes to sheep erythrocytes.
 Neither of the doses of Septilin altered weight gain, absolute lymphocyte counts, or host resistance against E. coli sepsis. The higher dose of Septilin reduced phagocytic activity of the PMN cells/reticuloendothelial system, but both doses increased the percentage and absolute number of circulating neutrophils, stimulated humoral immunity and suppressed cellular immunity.

Thus, Septilin has dual effects on the immune system, with lower doses showing greater stimulant and higher doses showing predominantly suppressant effects. Copyright © 2002 John Wiley & Sons, Ltd.
The long arm of the lab laws
Authors: Novak Roger A.
Published: August 2002

This paper may be viewed at the American Chemical Society's website (http://pubs.acs.org/subscribe/journals/tcaw/10/i11/html/11regs.html)
Assessing computer systems against 21 CFR Part 11: developing a checklist
Authors: Carter Angela , Lou Clark Mary
Published: August 2002

A 21 CFR Part 11 Checklist can satisfy many business, process, and educational needs of companies that use computer systems that must comply with Part 11. This article identifies a strategy for creating your own Part 11 Checklist. Suggestions are presented for: analyzing and sorting the regulations into manageable units; organizing the Checklist; adding supportive information to help users understand and navigate through the Checklist; and including enhancement features such as information mapping and special software. Finally, a sample excerpt from our own Checklist is provided. Copyright © 2002 John Wiley & Sons, Ltd.
A visual interface for model‐fitting
Authors: Smith Andrew J , Malik Zahid , Nelder John , Spence Robert
Published: August 2002

We describe a tool which supports the activity of a human being in fitting a mathematical model to measured or simulated data. The tool offers two principal advantages; its use requires a minimum of statistical knowledge, and its visual and interactive nature ensures that its use is intuitive. The tool is novel in that, in the iterative and often exploratory construction of a model, it represents graphically the benefit of all possible single changes to the existing model; a single selection action suffices to add a new term to a model or to remove it. Copyright © 2001 John Wiley & Sons, Ltd.
A new approach to solving problems of multi‐state system reliability optimization
Authors: Levitin Gregory , Lisnianski Anatoly
Published: August 2002

Usually engineers try to achieve the required reliability level with minimal cost. The problem of total investment cost minimization, subject to reliability constraints, is well known as the reliability optimization problem. When applied to multi‐state systems (MSS), the system has many performance levels, and reliability is considered as a measure of the ability of the system to meet the demand (required performance). In this case, the outage effect will be essentially different for units with different performance rate. Therefore, the performance of system components, as well as the demand, should be taken into account. In this paper, we present a technique for solving a family of MSS reliability optimization problems, such as structure optimization, optimal expansion, maintenance optimization and optimal multistage modernization. This technique combines a universal generating function (UGF) method used for fast reliability estimation of MSS and a genetic algorithm (GA) used as an optimization engine. The UGF method provides the ability to estimate relatively quickly different MSS reliability indices for series‐parallel and bridge structures. It can be applied to MSS with different physical nature of system performance measure. The GA is a robust, universal optimization tool that uses only estimates of solution quality to determine the direction of search. Copyright © 2001 John Wiley & Sons, Ltd.
Analyzing experiments with degradation data for improving reliability and for achieving robust reliability
Authors: Chiao Chih‐Hua , Hamada Michael
Published: August 2002

Statistically designed experiments provide a proactive means for improving reliability; moreover, they can be used to design products that are robust to noise factors which are hard or impossible to control. Traditionally, failure‐time data have been collected; for high‐reliability products, it is unlikely that failures will occur in a reasonable testing period, so the experiment will be uninformative. An alternative, however, is to collect degradation data. Take, for example, fluorescent lamps whose light intensity decreases over time. Observation of light‐intensity degradation paths, given that they are smooth, provides information about the reliability of the lamp, and does not require the lamps to fail. This paper considers experiments with such data for ‘reliability improvement’, as well as for ‘robust reliability achievement’ using Taguchi's robust design paradigm. A two‐stage maximum‐likelihood analysis based on a nonlinear random‐effects model is proposed and illustrated with data from two experiments. One experiment considers the reliability improvement of fluorescent lamps. The other experiment focuses on robust reliability improvement of light‐emitting diodes. Copyright © 2001 John Wiley & Sons, Ltd.
Ab initio calculations of the structural, energetic, and vibrational properties of some hydrogen bonded and van der Waals dimers. Part 4. The acetonitrile dimer
Authors: Ford Thomas A. , Glasser Leslie
Published: August 2002

The structures, interaction energies, Mulliken atomic charges, and vibrational spectra of five dimers of acetonitrile, CH3CN, have been determined by means of ab initio molecular orbital theory, at the second order level of Møller–Plesset perturbation theory, using the 6‐31++G(d,p) split‐valence polarized basis set, augmented with diffuse functions. The structural features of the dimers are discussed, as well as their respective interaction energies, which have been corrected for basis set superposition error by the full counterpoise technique of Boys and Bernardi. The atomic charge reorganizations resulting from dimerization have also been discussed. The vibrational wavenumbers and infrared intensities of each dimer have been computed and, in the case of the most probable dimer, they have been used to determine the wavenumber shifts relative to the corresponding modes of the monomer. The shifts have been compared with those in the infrared and Raman spectra of acetonitrile molecules trapped in cryogenic matrices, previously reported in the literature. The computed and experimental results support the conclusion that the favored dimer structure is a centrosymmetric cyclic species of C2h symmetry, stabilized by two weak CHN hydrogen bonds. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 226–240, 2001
Rearrangement with formamide extrusion in the electrospray mass spectra of aminoacylbenzylamines
Authors: Chen Jing , Jiang Yang , Fu Hua , Chen Yi , Cheng Chang‐mei , Zhao Yu‐fen
Published: August 2002

Several aminoacylbenzylamines and their analogs were synthesized and analyzed by electrospray ionization mass spectrometry together with high‐resolution and tandem mass spectrometric techniques. Fragment ions ([M + H − CH3NO]+) were observed and attributed to a transfer of the benzyl group to the N‐terminal amino group, leading to elimination of formamide. The proposed mechanism is supported by accurate mass measurements, and by experiments on deuterium labeling and variations of functional groups. Copyright © 2001 John Wiley & Sons, Ltd.
Bioactive dahlein peptides from the skin secretions of the Australian aquatic frog Litoria dahlii: sequence determination by electrospray mass spectrometry
Authors: Wegener Kate L. , Brinkworth Craig S. , Bowie John H. , Wallace John C. , Tyler Michael J.
Published: August 2002

Eleven dahlein peptides are present in the skin secretion of the Australian aquatic frog Litoria dahlii. All peptides have been sequenced using a combination of electrospray mass spectrometry (ES‐MS) and Lys‐C digestion/MS, with each sequence confirmed by automated Edman sequencing. The 13‐residue dahlein 1 peptides (e.g. dahlein 1.1 GLFDIIKNIVSTL‐NH2) exhibit weak wide‐spectrum antimicrobial activity but no significant activity in the anticancer testing program of the National Cancer Institute (Washington). There are no potent antimicrobial peptides present in the glandular secretion, but the dahleins 5 strongly inhibit the formation of NO by neuronal nitric oxide synthase (e.g. dahlein 5.1 GLLGSIGNAIGAFIANKLKP‐OH). Copyright © 2001 John Wiley & Sons, Ltd.
Quantitative determination of perfluorooctanoic acid ammonium salt in human serum by high‐performance liquid chromatography with atmospheric pressure chemical ionization tandem mass spectrometry
Authors: Sottani Cristina , Minoia Claudio
Published: August 2002

A sensitive, specific, accurate and reproducible analytical method was developed and validated to quantify perfluorooctanoic acid (PFOA) in human serum. After initial extraction with an ion‐paring reagent, the procedure for quantifying PFOA is based on high‐performance liquid chromatography (HPLC) interfaced to negative ion tandem mass spectrometry, operating in selected ion monitoring mode. The retention times of PFOA and its internal standard (D,L‐malic acid) were 5.85 and 1.70 min, respectively. The assay was linear over the range 0–500 ng/mL, with a lower limit of quantification (LOQ) of 25 ng/mL, and with a coefficient of variation (CV) of 7.3%. The lower limit of detection (LOD) was assessed as 10 ng/mL. The overall precision and accuracy were assessed on three different days. The within‐ and between‐day precision was ≤9.7 and 6.8%, respectively, and the accuracy was in the range 96–114%. The mean extracted recovery assessed at three different concentrations (100, 250, and 500 ng/mL) was always more than 85%. With this method no derivatization procedure was needed, thus avoiding possible thermal and chemical decomposition reactions of PFOA. The assay was applied to quantify perfluorooctanoic acid in serum from employees exposed to fluorochemicals commonly used in industrial applications for polymer production. The quantitative results for PFOA blood levels were found to vary between 100 and 982 ng/mL. Copyright © 2002 John Wiley & Sons, Ltd.
Electron impact mass spectral fragmentation of chiral bisbenzoxazole, bisbenzothiazole and biscarbamide derivatives of 2,2‐dimethyl‐1,3‐dioxolane
Authors: Xu Jiaxi , Jiao Peng , Deng Dayi , Zhang Qihan , Tsang Chun Wai , Chan Albert S. C.
Published: August 2002

The mass spectrometric fragmentation behaviour of five pairs of (R,R)‐ and (S,S)‐4,5‐bis(benzoxazol‐2‐yl)‐2,2‐dimethyl‐1,3‐dioxolane derivatives, one pair of (R,R)‐ and (S,S)‐4,5‐bis(benzothiazol‐2‐yl)‐2,2‐dimethyl‐1,3‐dioxolanes, and three pairs of (R,R)‐ and (S,S)‐N,N′‐bis(2‐hydroxyaryl)‐2,2‐dimethyl‐1,3‐dioxolane‐4,5‐dicarbamides, all important compounds for asymmetric catalysis (P. Jiao et al., Tetrahedron Asymmetry 2001; 12: 3081), has been studied with the aid of mass‐analyzed ion kinetic energy spectrometry and accurate mass measurements under electron impact ionization conditions. The spectral observations have been rationalized in terms of fragment ion structures and fragmentation mechanisms that will provide an aid to spectral interpretation for new compounds of this type. Copyright © 2002 John Wiley & Sons, Ltd.
Hepatitis B virus (HBV) reactivation after cytotoxic or immunosuppressive therapy — pathogenesis and management
Authors: Xunrong Luo , Wing Yan Au , Liang Raymond , Lau George K. K.
Published: August 2002

In an endemic area for chronic hepatitis B infection, reactivation of this virus is a serious cause of morbidity and mortality in patients undergoing cytotoxic or immunosuppressive therapy. Careful prospective serological testing has shown that hepatitis B virus reactivation is a two‐staged process. The initial stage occurs during intense cytotoxic or immunosuppressive therapy and is characterised by enhanced viral replication, as reflected by increases in the serum levels of hepatitis B virus DNA, hepatitis B e antigen, hepatitis B virus DNA polymerase and infection of naïve hepatocytes with hepatitis B virus. The second stage is related to restoration of immune function following withdrawal of cytotoxic or immunosuppressive therapy, which causes rapid immune‐mediated destruction of infected hepatocytes. Clinically, this can lead to hepatitis, hepatic failure and even death. The occurrence and severity of hepatitis B virus reactivation after various cytotoxic or immunosuppressive therapy is unpredictable and treatment has been disappointing, largely due to the late administration of therapy. Recently, pre‐emptive treatment of chronic hepatitis B patients undergoing cytotoxic or immunosuppressive therapy, with potent nucleoside analogues has shown some promising results. Further controlled studies are needed to define the incidence and risk factors of hepatitis B reactivation so that pre‐emptive treatment with nucleoside analogues could be administered to those patients at high risk of disease. Copyright © 2001 John Wiley & Sons, Ltd.
Adaptive exponential stabilization of mobile robots with unknown constant‐input disturbance
Authors: Wu Weiguo , Chen Huitang , Wang Yuejuan , Woo Peng‐Yung
Published: August 2002

This paper concentrates on the discussions on stabilization of mobile robots with unknown constant‐input disturbance. Continuous time‐varying adaptive controllers are designed for mobile robots in a chain‐form by using Lyapunov approach. With the property of homogeneous systems, uncertain mobile robots governed by the proposed control algorithms become homogeneous of order 0 to achieve exponential stability. Simulation results validate the theoretical analysis. © 2001 John Wiley & Sons, Inc.
A method for determining movements of a deformable body from spatial coordinates of markers
Authors: Lenarčič Jadran , Parenti‐Castelli Vincenzo
Published: August 2002

In this article, we present a numerical method to compute the relative displacement of a body that deforms
during movement. It is assumed that a group of markers is attached to the body's surface, and that their
spatial positions are obtained by an optical measurement system. The measured coordinates of markers are
perturbed by measurement inaccuracies and by the deformation of the body. The mathematical objective is to find
the best match between two subsequent images. The proposed numerical method has the same properties in treating
random‐type perturbations as a standard least‐squares technique, but it is more efficient in
minimizing the effect of the body's deformations. The method can be utilized in determining human
movements from inaccurate optical measurements. © 2001 John Wiley & Sons, Inc.
Cloud attenuation modelling for SHF and EHF applications
Authors: Dissanayake Asoka , Allnutt Jeremy , Haidara Fatim
Published: August 2002

Tropospheric propagation impairments that affect earth–space communication signals increase in severity with the increase of frequency. Introduction of satellite services using higher frequency bands such as Ka‐ and V‐band requires the characterization of propagation factors that are normally considered negligible at lower frequency bands. Cloud attenuation is considered one such factor. Clouds are present during a large fraction of an average year and cloud attenuation, together with gaseous absorption, will determine the system performance under non‐rainy conditions. A cloud attenuation model that has global applicability is presented in this paper. The model is based on average properties of four cloud types and their occurrence probabilities. The occurrence probabilities are derived from long‐term observations of cloud cover carried out by several thousand meteorological stations throughout the world. Predictions made with the model are compared with cloud attenuation data gathered using Ka‐band beacon signals and radiometers. Copyright © 2001 John Wiley & Sons, Ltd.
Interfaces in magnesium‐based composites
Authors: Mordike Barry L. , Lukáč Pavel
Published: August 2002

The properties of composites are dependent on the properties of the interfaces between the matrix and the reinforcement material. This paper describes how the interface can influence the various properties and also the various methods that can be used to determine the nature of the interface, both directly by microscopy or indirectly by electrical measurements or acoustic emission. Copyright © 2001 John Wiley & Sons, Ltd.
Evaluation of amine‐ and amide‐terminated self‐assembled monolayers as ‘Molecular glues’ for Au and SiO2 substrates
Authors: Hooper A. E. , Werho D. , Hopson T. , Palmer O.
Published: August 2002

A series of organic monolayers containing amine and amide functional groups on silicon and gold substrates were characterized using x‐ray photoelectron and infrared spectroscopies. It was determined that the amine‐terminated monolayers had 70% of the amine groups in the —NH2 chemical state after removal from pure water. Next, Escherichia coli bacteria were exposed to the surfaces in order to evaluate the effectiveness of the monolayers as molecular adhesive agents. It was determined that the bacteria adhere readily to all of the amine monolayers but did not interact with the amide‐ containing monolayer. Copyright © 2001 John Wiley & Sons, Ltd.
Radio frequency GDOES depth profiling analysis of a B‐doped diamond film deposited onto Si by microwave plasma CVD
Authors: Shimizu K. , Einaga Y. , Ohnishi K. , Fujishima A. , Habazaki H. , Skeldon P. , Thompson G. E.
Published: August 2002

Analysis of a boron‐doped diamond film, ∼13 µm thick, deposited onto a mirror‐finished n‐Si(100) substrate using microwave plasma chemical vapour deposition (CVD), demonstrates the suitability of radiofrequency glow discharge optical emission spectroscopy (rf‐GDOES) for rapid depth profiling analysis. The distributions of boron and hydrogen are revealed clearly. Interestingly, the sputtering of the diamond film is accompanied by smoothing of the initial rough, faceted surface, implying that the ridges sputter more rapidly than the valleys during analysis. Copyright © 2002 John Wiley & Sons, Ltd.
Mesophase‐derived nucleic acid (peptide) self‐organizations visualized by scanning force microscopy
Authors: Meister Walter‐Veselý , Bohley Christian , Lindau Sabine , Gromann Ulrich , Naumann Stefan , Herrmann Bernd , Kargov Sergej I. , Martini Torsten , Barthel Jochen , Hoffmann Siegfried
Published: August 2002

For approaching biomesogen self‐organizations in nucleic acid (peptide) assemblies from the perspective of interacting individual macromolecules and their integrating collective mesophase organizations, DNA duplex as well as RNA duplex, triplex, quadruplex and duplex/peptide domains and microdomains have been visualized as graphite surface adlayers by scanning force microscopy. Derived from corresponding mesophase designs, the adlayer imagings of dsDNA, dsRNA and qsRNA reveal aligned supramolecular bundles that follow self‐organizational strategies within the adlayer/interface restrictions. For tsRNA and dsRNA/oligo‐ and polypeptide variations more complex adlayer organizations are observed. Copyright © 2002 John Wiley & Sons, Ltd.
Characterization of silicon gate oxides by conducting atomic force microscopy
Authors: Kremmer S. , Teichert C. , Pischler E. , Gold H. , Kuchar F. , Schatzmayr M.
Published: August 2002

Characteristics of the dielectric breakdown and the thickness homogeneity of silicon gate oxides have been investigated on the nanometre scale using conducting atomic force microscopy (C‐AFM). The I–V measurements in the Fowler– Nordheim tunnelling regime were applied in order to use C‐AFM as an experimental technique for the thickness determination of thin silicon gate oxides. Conducting AFM was used further to study dielectric breakdown with a lateral resolution below 100 nm. It was found that the accumulation of defects created by induced charges and a statistic path formation of these defects are the main mechanisms leading to dielectric breakdown. Copyright © 2002 John Wiley & Sons, Ltd.
Methods for evaluating the performance of diagnostic tests in the absence of a gold standard: a latent class model approach
Authors: Garrett Elizabeth S. , Eaton William W. , Zeger Scott
Published: August 2002

In many areas of medical research, ‘gold standard’ diagnostic tests do not exist and so evaluating the performance of standardized diagnostic criteria or algorithms is problematic. In this paper we propose an approach to evaluating the operating characteristics of diagnoses using a latent class model. By defining ‘true disease’ as our latent variable, we are able to estimate sensitivity, specificity and negative and positive predictive values of the diagnostic test. These methods are applied to diagnostic criteria for depression using Baltimore's Epidemiologic Catchment Area Study Wave 3 data. Copyright © 2002 John Wiley & Sons, Ltd.
Internal capabilities, external networks, and performance: a study on technology‐based ventures
Authors: Lee Choonwoo , Lee Kyungmook , Pennings Johannes M.
Published: August 2002

This study examined the influence of internal capabilities and external networks on firm performance by using data from 137 Korean technological start‐up companies. Internal capabilities were operationalized by entrepreneurial orientation, technological capabilities, and financial resources invested during the development period. External networks were captured by partnership‐ and sponsorship‐based linkages. Partnership‐based linkages were measured by strategic alliances with other enterprises and venture capitalists, collaboration with universities or research institutes, and participation in venture associations. Sponsorship‐based linkages consisted of financial and nonfinancial support from commercial banks and the Korean government. Sales growth indicated the start‐up's performance. Regression results showed that the three indicators of internal capabilities are important predictors of a start‐up's performance. Among external networks, only the linkages to venture capital companies predicted the start‐up's performance. Several interaction terms between internal capabilities and partnership‐based linkages have a statistically significant influence on performance. Sponsorship‐based linkages do not have individual effects on performance but linkage with financial institutions has a multiplicative effect with technological capabilities and financial resources invested on a start‐up's performance. Implications and directions for future research were discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Strategic entrepreneurship: entrepreneurial strategies for wealth creation
Authors: Hitt Michael A. , Ireland R. Duane , Camp S. Michael , Sexton Donald L.
Published: August 2002

Entrepreneurship involves identifying and exploiting entrepreneurial opportunities. However, to create the most value entrepreneurial firms also need to act strategically. This calls for an integration of entrepreneurial and strategic thinking. We explore this strategic entrepreneurship in several important organizational domains to include external networks and alliances, resources and organizational learning, innovation and internationalization. The research in this special issue examines both traditional (e.g., contingency theory, strategic fit) and new theory (e.g., cultural entrepreneurship, business model drivers). The research also integrates, extends, and tests theory and research from entrepreneurship and strategic management in new ways such as creative destruction (discontinuities), resource‐based view, organizational learning, network theory, transaction costs and institutional theory. The research presented herein provides a basis for future research on strategic entrepreneurship for wealth creation. Copyright © 2001 John Wiley & Sons, Ltd.
Realism and constructivism in strategy research: a critical realist response to Mir and Watson
Authors: Kwan Kai‐Man , Tsang Eric W. K.
Published: August 2002

Mir and Watson (2000) advocate that constructivism has the potential to inform strategy research. In their discussions, they compare constructivism with realism, and highlight certain alleged strengths of the former over the latter. Although their paper provides some insights, their version of constructivism is problematic and their understanding of realism is inaccurate. In this note we clarify some key issues concerning constructivism and realism. Moreover, we argue that Mir and Watson's insights can be accommodated within a critical realist framework. Copyright © 2001 John Wiley & Sons, Ltd.