bluuebunny/crossref_metadata_2025 huggingface dataset:
Lymphotoxin β–mediated stimulation of synoviocytes in rheumatoid arthritis
Authors: Braun Andrea , Takemura Seisuke , Vallejo Abbe N. , Goronzy Jörg J. , Weyand Cornelia M.
Published: July 2004

Objective

Lymphotoxin β (LTβ), a cytokine produced by T cells and B cells, plays a central role in the normal development of lymph nodes and is critical in the formation of ectopic germinal center reactions in rheumatoid synovitis. Because resident fibroblast‐like synoviocytes (FLS) express receptors for LTβ, we examined the consequences of FLS activation by LTβ.

Methods

FLS from patients with rheumatoid arthritis were isolated and examined for the expression of LTβ receptor. FLS were incubated with LTα1β2 and assayed for the production of cytokines and chemokines and the up‐regulation of adhesion molecules.

Results

Exposure of FLS to recombinant LTα1β2 resulted in the production of multiple inflammatory cytokines and metalloproteinases, implicating FLS as amplifiers of the inflammatory process in the inflamed joint. Additionally, LTα1β2 was found to up‐regulate the expression of cell adhesion molecules, rendering FLS to efficient adhesion substrates for T cells. LTα1β2 also induced production of the chemokines CCL2 and CCL5, which elicited transmigration activity of T cells. Upon stimulation with LTα1β2, FLS did not acquire characteristics of follicular dendritic cells.

Conclusion

These data document that FLS are involved in multiple stages of the inflammatory process, including the recruitment and retention of lymphocytes in the synovial microenvironment. We propose that the heterotypic interaction between LTβ‐producing lymphocytes and responding FLS contributes to the establishment of complex lymphoid microstructures, and that this may be one element that defines susceptibility of the synovial membrane to lymphoid organogenesis.
Dissection of class III major histocompatibility complex haplotypes associated with rheumatoid arthritis
Authors: Newton Julia L. , Harney Sinéad M. J. , Timms Andrew E. , Sims Anne‐Marie , Rockett Kirk , Darke Chris , Wordsworth B. Paul , Kwiatkowski Dominic , Brown Matthew A.
Published: July 2004

Objective

We have previously identified a single‐nucleotide polymorphism (SNP) haplotype involving the lymphotoxin α (LTA) and tumor necrosis factor (TNF) loci (termed haplotype LTA–TNF2) on chromosome 6 that shows differential association with rheumatoid arthritis (RA) on HLA–DRB1*0404 and *0401 haplotypes, suggesting the presence of additional non–HLA–DRB1 RA susceptibility genes on these haplotypes. To refine this association, we performed a case–control association study using both SNPs and microsatellite markers in haplotypes matched either for HLA–DRB1*0404 or for HLA–DRB1*0401.

Methods

Fourteen SNPs lying between HLA–DRB1 and LTA were genotyped in 87 DRB1*04‐positive families. High‐density microsatellite typing was performed using 24 markers spanning 2,500 kb centered around the TNF gene in 305 DRB1*0401 or *0404 cases and 400 DRB1*0401 or *0404 controls. Single‐marker, 2‐marker, and 3‐marker minihaplotypes were constructed and their frequencies compared between the DRB1*0401 and DRB1*0404 matched case and control haplotypes.

Results

Marked preservation of major histocompatibility complex haplotypes was seen, with chromosomes carrying LTA–TNF2 and either DRB1*0401 or DRB1*0404 both carrying an identical SNP haplotype across the 1‐Mb region between TNF and HLA–DRB1. Using microsatellite markers, we observed two 3‐marker minihaplotypes that were significantly overrepresented in the DRB1*0404 case haplotypes (P = 0.00024 and P = 0.00097).

Conclusion

The presence of a single extended SNP haplotype between LTA–TNF2 and both DRB1*0401 and DRB1*0404 is evidence against this region harboring the genetic effects in linkage disequilibrium with LTA–TNF2. Two RA‐associated haplotypes on the background of DRB1*0404 were identified in a 126‐kb region surrounding and centromeric to the TNF locus.
Dichotomous effects of complete versus partial class II major histocompatibility complex deficiency on circulating autoantibody levels in autoimmune‐prone mice
Authors: Stohl William , Xu Dong , Metzger Troy E. , Kim Kyoung Soo , Morel Laurence , Kotzin Brian L.
Published: July 2004

Objective

To assess the effects of altered class II major histocompatibility complex (MHCII) expression on circulating autoantibody levels in C57BL/6 (B6) mice congenic for the Sle1 (B6.Sle1 mice) or Nba2 (B6.Nba2 mice) regions.

Methods

H‐2Ab+/+ (MHCII‐intact), H‐2Ab+/– (MHCII‐intermediate), and H‐2Ab–/– (MHCII‐deficient) littermate B6.Sle1 and B6.Nba2 mice were evaluated for spleen cell phenotype, numbers of splenic Ig‐secreting cells, and serum levels of total IgM, total IgG, IgG antichromatin, IgG antihistone, and IgG anti–double‐stranded DNA (anti‐dsDNA).

Results

Compared with their MHCII‐intact littermates, MHCII‐deficient B6.Sle1 and B6.Nba2 mice developed markedly decreased circulating levels of IgG autoantibodies, along with decreased circulating levels of total IgG. In sharp contrast, MHCII‐intermediate mice developed increased circulating levels of IgG autoantibodies. This was associated with increased numbers of splenic Ig‐secreting cells and serum levels of total IgG in B6.Sle1 mice, but it occurred without concomitant increases in the numbers of splenic Ig‐secreting cells or serum total IgG levels in B6.Nba2 mice.

Conclusion

In 2 clinically healthy strains of mice with a genetic proclivity for developing autoantibodies, the effects of class II MHC expression on levels of circulating IgG autoantibodies were found to be complex. In the absence of MHCII expression, circulating IgG autoantibody levels were minimal. With full MHCII expression, circulating IgG autoantibody levels were considerable. With intermediate MHCII expression, circulating IgG autoantibody levels were even greater. These last findings may help explain why heterozygosity at the H‐2 locus is associated with increased autoantibody titers and aggravated disease in certain lupus‐prone mice.
Sulfasalazine is a potent inhibitor of the reduced folate carrier: Implications for combination therapies with methotrexate in rheumatoid arthritis
Authors: Jansen Gerrit , van der Heijden Joost , Oerlemans Ruud , Lems Willem F. , Ifergan Ilan , Scheper Rik J. , Assaraf Yehuda G. , Dijkmans Ben A. C.
Published: July 2004

Objective

To investigate whether interactions of sulfasalazine (SSZ) with reduced folate carrier (RFC), the dominant cell membrane transporter for natural folates and methotrexate (MTX), may limit the efficacy of combination therapy with MTX and SSZ in patients with rheumatoid arthritis.

Methods

Human RFC‐(over)expressing CEM cells of T cell origin were used to analyze the effect of SSZ on the RFC‐mediated cellular uptake of radiolabeled MTX and the natural folate leucovorin. Moreover, both cells with and those without acquired resistance to SSZ were used to assess the antiproliferative effects of MTX in combination with SSZ.

Results

Transport kinetic analyses revealed that SSZ was a potent noncompetitive inhibitor of RFC‐mediated cellular uptake of MTX and leucovorin, with mean ± SD Ki (50% inhibitory concentration) values of 36 ± 6 μM and 74 ± 7 μM, respectively. Consistent with the inhibitory interaction of SSZ with RFC, a marked loss of MTX efficacy was observed when MTX was coadministered with SSZ: up to 3.5‐fold for CEM cells in the presence of 0.25 mM of SSZ, and >400‐fold for SSZ‐resistant cells in the presence of 2.5 mM of SSZ. Importantly, along with diminished efficacy of MTX, evidence for cellular folate depletion was obtained by the demonstration of an SSZ dose–dependent decrease in leucovorin accumulation.

Conclusion

At clinically relevant plasma concentrations, interactions of SSZ with RFC provide a biochemical rationale for 2 important clinical observations: 1) the onset of (sub)clinical folate deficiency during SSZ treatment, and 2) the lack of additivity/synergism of the combination of SSZ and MTX when these disease‐modifying antirheumatic drugs are administered simultaneously. Thus, when considering use of these drugs in combination therapies, the present results provide a rationale both for the use of folate supplementation and for spacing administration of these drugs over time.
Postoperative mortality following oesophagectomy and problems in reporting its rate
Authors: Jamieson G G , Mathew G , Ludemann R , Wayman J , Myers J C , Devitt P G
Published: July 2004

Background

There have been three previous reviews of the world literature describing postoperative mortality rate following oesophagectomy. The first documented rates in the first half of the last century, the second the period 1960–1979 and the third the interval 1980–1988. The aim of this review was to document the rate for the period 1990–2000.

Methods

Reports were sourced through PubMed and/or Medline listings.

Results

The number of papers included in the review was 312, involving 70 756 patients. The overall mortality rate was 6·7 per cent. The 30-day mortality rate was 4·9 per cent and the in-hospital mortality rate 8·8 per cent. Survival rates, where reported, were 62·7 per cent at 1 year and 27·9 per cent at 5 years.

Conclusion

Operative mortality rates following oesophagectomy have continued to fall. However, the true rate is almost certainly higher than that reported here, for a variety of reasons. The 1-year survival of patients was only reported in about a quarter of the papers. It may be a more meaningful figure than postoperative mortality rate.
Fenitrothion‐induced changes in lipids of rats
Authors: Roy Shalini , Roy Sharmila , Sharma C. B.
Published: July 2004

The dose‐dependent lipid accumulation caused by fenitrothion administration is associated with alteration of the ratio of various components of phospholipids and neutral lipids in various organs of rats up to 48 h. The concentration of triacylglycerol, phosphatidyl choline, phosphatidyl ethanolamine and phosphatidyl glycerol increased in liver, kidney and brain in treated rats whereas phosphatidyl serine was greatly reduced. High‐performance liquid chromatography and gas–liquid chromatography were used for quantiative analysis of phospholipids and triacylglycerol. The changes in relative composition of various lipids by fenitrothion administration may lead to malfunctioning and alteration of biological properties. Copyright © 2004 John Wiley & Sons, Ltd.
Quantitative analysis of bucillamine in blood using high‐performance liquid chromatography–mass spectrometry technique
Authors: Beaudry Francis , Proulx Dave , Furtado Milton
Published: July 2004

A fast and sensitive method has been developed and validated for the determination of bucillamine in human blood by derivatizing the free sulfhydryl groups with isobutyl acrylate (IA), by APCI‐LC/MS/MS. The collected blood sample was immediately mixed with a mixture of IA and 0.05 m Tris(hydroxymethyl)aminomethane hydrochloride (Tris–HCl) buffer, pH 9.2, to stabilize the sulfyhydryl moieties. The derivatized samples were then extracted by protein precipitation, evaporated, reconstituted and injected using an LC‐APCI/MS/MS instrument. Separation was achieved using a C18 analytical column and a gradient mobile phase within a chromatographic run time of 5 min. A quadratic (weighted 1/concentration2) relationship was observed during validation over a concentration range of 0.4–40 µg/mL with a correlation value of r ≥ 0.9966. The inter‐batch precision and accuracy at low, medium and high concentrations were 8.1, 8.4 and 7.3%; 113.3, 104.9 and 103.9%, respectively, and the intra‐batch precision and accuracy at low, medium and high concentrations were 7.7, 5.4 and 2.7%; 105.1, 111.9 and 113.2%, respectively. Copyright © 2004 John Wiley & Sons, Ltd.
Sequence alignment on the Cray MTA‐2
Authors: Bokhari Shahid H. , Sauer Jon R.
Published: July 2004

Several variants of standard algorithms for DNA sequence alignment have been implemented on the Cray Multithreaded Architecture‐2 (MTA‐2). We describe the architecture of the MTA‐2 and discuss how its hardware and software enable efficient implementation of parallel algorithms with little or no regard for issues of partitioning, mapping or scheduling. We describe how we ported variants of the naive algorithm for exact alignment and the dynamic programming algorithm for approximate alignment to the MTA‐2 and provide detailed performance measurements. It is shown that, for the dynamic programming algorithm, the use of the MTA's ‘Full/Empty’ synchronization bits leads to almost perfect speedup for large problems on one to eight processors. These results illustrate the versatility of the MTA's architecture and demonstrate its potential for providing a high‐productivity platform for parallel processing. Copyright © 2004 John Wiley & Sons, Ltd.
Using hybrid alignment for iterative sequence database searches
Authors: Li Yuheng , Lauria Mario , Bundschuh Ralf
Published: July 2004

Progressive sequence model refinement by means of iterative searches is an effective technique for high sensitivity database searches and is currently employed in popular tools such as PSI‐BLAST and SAM. Recently, a novel alignment algorithm has been proposed that offers features expected to improve the sensitivity of such iterative approaches, specifically a well‐characterized theory of its statistics even in the presence of position‐specific gap costs. Here, we demonstrate that the new hybrid alignment algorithm is ready to be used as the alignment core of PSI‐BLAST. In addition, we evaluate the accuracy of two proposed approaches to edge effect correction in short sequence alignment statistics that turns out to be one of the crucial issues in developing a hybrid‐alignment based version of PSI‐BLAST. Copyright © 2004 John Wiley & Sons, Ltd.
Development and implementation of a parallel algorithm for the fast design of oligonucleotide probe sets for diagnostic DNA microarrays
Authors: Meier H. , Krause A. , Kräutner M. , Bode A.
Published: July 2004

We describe an accurate method for the automatic parallel generation of oligonucleotide probe sets for DNA microarrays. This approach includes a component for high‐performance specificity evaluation of designed probes in large data sets. The three main algorithmic components of the method, namely probe preselection, hybridization prediction and probe selection are explained in detail. We introduce new combinatorial techniques for the efficient selection of probe sets of high differentiation capability even from sequence databases of conserved homologous genes. These techniques include the automatic generation of group specific probes as well as the design of excluding probes. A basic prototype has been implemented including a shared memory parallelization. Test runs have been performed on a multiprocessor personal computer with subsets of a small subunit ribosomal ribonucleic acid database, containing very conserved sequence data. The applicability of our program is pointed out by designing a set of oligonucleotide probes that shall allow a comprehensive parallel identification and differentiation of several groups of extremophilic prokaryotes by DNA microarray. The probe set is accessible via the Internet. On applying the parallel version on a dual processor system an efficiency of 80% was achieved. Copyright © 2004 John Wiley & Sons, Ltd.
A hybrid self‐organizing maps and particle swarm optimization approach
Authors: Xiao Xiang , Dow Ernst R. , Eberhart Russell , Ben Miled Zina , Oppelt Robert J.
Published: July 2004

Gene clustering, the process of grouping related genes in the same cluster, is at the foundation of different genomic studies that aim at analyzing the function of genes. Microarray technologies have made it possible to measure gene expression levels for thousands of genes simultaneously. For knowledge to be extracted from the datasets generated by these technologies, the datasets have to be presented to a scientist in a meaningful way. Gene clustering methods serve this purpose. In this paper, a hybrid clustering approach that is based on self‐organizing maps and particle swarm optimization is proposed. In the proposed algorithm, the rate of convergence is improved by adding a conscience factor to the self‐organizing maps algorithm. The robustness of the result is measured by using a resampling technique. The algorithm is implemented on a cluster of workstations. Copyright © 2004 John Wiley & Sons, Ltd.
A specialized hardware device for the protein similarity search
Authors: Marongiu A. , Palazzari P. , Rosato V.
Published: July 2004

This work presents the architecture of PROSIDIS, a special purpose processor designed to search for the occurrence of substrings similar to a given ‘template string’ within a proteome. Similarity is determined by means of a weighting matrix which measures the degree of similarity between any two amino acids.

The paper recalls the basis of the PHG (Parallel Hardware Generator) tool, developed in the framework of the HADES project (Hardware Design for Scientific Applications). Through PHG it is possible to design, in a nearly automatic way, a parallel hardware which efficiently implements an algorithm described through recurrence equations; PHG is able to generate a synthesizable VHDL which represents a parallel system derived from the System of Affine Recurrence Equations (SARE) describing the problem.

In this work we illustrate the advantages derived from designing a special purpose processor to face the protein similarity discovery problem. Some preliminary results are given, reporting the time spent by several conventional computing architectures and by the PROSIDIS processor hosted by a personal computer to solve the same protein analysis problem. The results show that PROSIDIS, implemented on a Xilinx XV1000 FPGA, gives speedup figures ranging from 5.6 up to 55.6. Copyright © 2004 John Wiley & Sons, Ltd.
Parallel divide and conquer approach for the protein threading problem
Authors: Yanev Nicola , Andonov Rumen
Published: July 2004

For the Protein Threading Problem (PTP) we propose a network‐flow like formulation. We also show its equivalence with a generalization of the shortest path problem on a graph with a very particular structure. The underlying Mixed Integer Programming (MIP) model proves to be very appropriate for the PTP—large real‐life instances have been solved much faster by using only the MIP solver CPLEX instead of a known special‐purpose branch and bound algorithm. The properties of the MIP model permit a decomposition of the main problem into a large number of subproblems (tasks). We show that a branch and cut strategy can be efficiently applied for solving these tasks in a parallel manner, which leads to a significant reduction in the total running time. Computational experiments with large problem instances are presented. Copyright © 2004 John Wiley & Sons, Ltd.
The AxML program family for maximum likelihood‐based phylogenetic tree inference
Authors: Stamatakis Alexandros P. , Ludwig Thomas , Meier Harald
Published: July 2004

Inference of phylogenetic (evolutionary) trees comprising hundreds or thousands of organisms based on the maximum likelihood criterion is a computationally extremely intensive task. This paper describes the evolution of the AxML program family which provides novel algorithmic as well as technical solutions for the maximum likelihood‐based inference of huge phylogenetic trees. Algorithmic optimizations and a new tree building algorithm yield runtime improvements of a factor greater than 4 compared with fastDNAml and parallel fastDNAml, returning equally good trees at the same time. Various parallel, distributed, and Grid‐based implementations of AxML give the program the capability to acquire the large amount of required computational resources for the inference of huge high‐quality trees. Copyright © 2004 John Wiley & Sons, Ltd.
Mice deficient in invariant‐chain and MHC class II exhibit a normal mature B2 cell compartment
Authors: Maehr Rene´ , Kraus Manfred , Ploegh Hidde L.
Published: July 2004

The role of the invariant chain (Ii), an MHC class II‐associated chaperone, in B cell development is controversial. Ii deficient mice (Ii–/– mice) show a defect in B cell development.This defect has been attributed to the absence of a fragment liberated from the Ii by intramembranous proteolysis. It was proposed that this fragment is required for activation of the NF‐κB pathway as a means of controlling B cell maturation. The opposing view holds that defects in the assembly of MHC class II molecules result in impaired B cell development. Here we demonstrate that a lack of Ii indeed causes defects in B cell development, with fewer mature B cells in the periphery as previously reported, but that in a compound‐mutant from which both Ii and all MHC class II subunits are absent, B cell development is normal. We suggest that neither Ii itself, nor the MHC class II products are required for normal B cell development.
Reactions of Group 13 and 14 Hydrides and Group 1, 2, 13 and 14 Organyl Compounds with (tert‐Butylimino)(2,2,6,6‐tetramethylpiperidino)borane
Authors: Braun Ulrike , Böck Barbara , Nöth Heinrich , Schwab Ingo , Schwartz Manfred , Weber Siegfried , Wietelmann Ulrich
Published: July 2004

(tert‐Butylimino)(2,2,6,6‐tetramethylpiperidino)borane (1) is a highly reactive species. Its B≡N triple bond inserts into the B−H bond of boranes, R2BH, generating diborylamines of the type tmp−BH−NtBu−BR2 (tmp = 2,2,6,6‐tetramethylpiperidino; R = H, Cl, Br, or organyl). Thexylborane reacts analogously, but only one of its two B−H bonds is used for the hydroboration of 1. However, dihaloboranes HB(Hal)2−SMe2 (Hal = Cl, Br) give B‐haloboration products tmp−B(Hal)−NtBu−BH(Hal), while reactions with H2B(Hal)−SMe2 produce a mixture of two isomers by competing hydroboration and haloboration reactions. Tmp−BH−NtBu−AlH2 was obtained from 1 and AlH3−NMe3. It is a dimer in the solid state with pentacoordinate Al atoms and AlH2Al bridges. Hydrosilylation of 1 was achieved with Me2SiHCl, SiHCl3 or Ph2SiH2 to give the N‐silyl‐substituted diaminoboranes tmp‐BH‐NtBu−SiX3−nRn. Me3SnH and Bu3SnH behave similarly, giving the corresponding N‐stannylated diaminoboranes. However, when Ph3SnH was treated with 1, the stannylborane tmp−B(SnPh3)−NHtBu was formed showing an umpolung of the hydrostannylation. Organyllithium compounds provide access to N‐lithiodiaminoboranes of the type tmp−BR−NtBu−Li. The stability of these compounds depends on the substituent R. The least stable compound was the B−tBu derivative followed by the B‐methyl compound. However, in the presence of TMEDA tmp−BMe−NtBu−Li is sufficiently stable to allow reactions, e.g. with B‐chlorocatecholborane, to produce tmp−BMe−NtBu−BO2C6H4. The most stable lithium compound so far is tmp−BPh−NtBu−Li−OEt2, whose structure has been determined by X‐ray crystallography. MgBu2 behaves like LiR and both of its Mg−C bonds can be used for the insertion reaction. The same is also true of ZnMe2. In contrast, at ambient temperature, only one of the E−C bonds of triorganylalanes, triorganylgallanes and InPh3 is used for the insertion reaction. In the solid state, most of the new compounds show a weak to strong coordinate bond between the electrophilic centre (Li, Mg, Zn, Cd, B, Al, Ga and In) and the nitrogen atom of the tmp group which generates a four‐membered ring. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Polynuclear Rhenium and Manganese Selenido‐Carbonyl Complexes − Reversible Square to Butterfly Conversion of the Re4Se2 Core by CO Loss in [Re4(µ3‐Se)2(CO)16(PPh3)2], and the Crystal Structure of [Mn2(µ2‐Se2)(CO)5(PPh3)2]
Authors: Belletti Daniele , Graiff Claudia , Pattacini Roberto , Predieri Giovanni , Tiripicchio Antonio
Published: July 2004

The reaction of Ph3PSe with [Mn2(CO)10] leads to the formation of [Mn4(μ3‐Se)2(μ‐CO)(CO)14(PPh3)2], which contains a butterfly “Mn2Se2 core”, along with traces of [Mn2(μ2‐Se2)(CO)5(PPh3)2] (1), which contains a tetrahedral Mn2Se2 core. The reaction of Ph3PSe with [Re2(CO)8(NCMe)2] affords two new complexes, [Re4(μ3‐Se)2(CO)16(PPh3)2] (2) and [Re4(μ3‐Se)2(μ‐CO)(CO)14(PPh3)2] (3). Their molecular structures, determined by X‐ray diffraction methods, exhibit a nearly square‐planar Re2Se2 and a butterfly Re2Se2 core, respectively. These air‐stable tetrarhenium selenido‐carbonyl species display a reversible loss/addition of a CO molecule, which is accompanied by the formation/cleavage of a Re−Re bond and the consequent rearrangement of the Re2Se2 core, from square to butterfly and vice versa. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis, Characterisation, Properties and X‐ray Structures of CuII Coordination Compounds with 5,5′‐Dimethylbipyridine and Various Anions: Control of Stoichiometry and Structure by the Counterions
Authors: van Albada Gerard A. , Mohamadou Aminou , Mutikainen Ilpo , Turpeinen Urho , Reedijk Jan
Published: July 2004

The synthesis, crystal structures, and electronic and magnetic properties of eight new CuII compounds containing the ligand 5,5‐dimethyl‐2,2,′‐bipyridine (dmbpy) with the general formula [CuII(dmbpy)x(L)2] (where L = BF4−, CF3SO3−, NO3−, Br−, NCS−, N3−, HCOO−, and x = 1−3) are reported. The geometries of the CuII ions include a four‐coordinate square‐planar polymeric compound [Cu(dmbpy)(N3)2]n (7), the five‐coordinate compounds, [Cu(dmbpy)2(C2H6O)](CF3SO3)2 (2), [Cu(dmbpy)2(NO3)](NO3) (3), [Cu(dmbpy)2(Br)]Br (5), [Cu(dmbpy)(NCS)2]n (6) and [Cu(dmbpy)2(HCOO)](CF3SO3) (8), which have geometries ranging from square pyramidal to trigonal bipyramidal, and the six‐coordinate compounds [Cu(dmbpy)3](BF4)2(C2H6O) (1) and [Cu(dmbpy)(NO3)2] (4), which adopt an octahedrally based geometry. Except for compounds 3 and 4, with nitrate as the anion, a variation of the copper/ligand ratios in the synthesis has no influence on the stoichiometry. The compounds have been characterised in detail by infrared, ligand field and EPR spectroscopy; the data are consistent with the single‐crystal X‐ray structures. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Structural Characterization of Bismuth(III) and Antimony(III) Chlorotriflates: Key Intermediates in Catalytic Friedel−Crafts Transformations
Authors: Mazières Stéphane , Le Roux Christophe , Peyronneau Magali , Gornitzka Heinz , Roques Nicolas
Published: July 2004

Chlorotriflates of antimony and bismuth ClnM(OSO2CF3)3−n (n = 1 or 2) are believed to be metallic intermediates of major importance in Friedel−Crafts reactions that use Bi(OSO2CF3)3, Sb(OSO2CF3)3, the systems BiCl3/CF3SO2OH or SbCl3/CF3SO2OH as catalysts. Unknown until now, the compounds ClBi(OSO2CF3)2 (1) and Cl2Sb(OSO2CF3) (2) have been synthesized by reaction of MCl3 (M = Bi, Sb) with triflic acid. After crystallization from THF, 1 and 2 were investigated in the solid state by X‐ray crystallography. Their use as catalysts in benzoylation of toluene, acylation of m‐xylene, and sulfonylation of toluene led to conclusive results, thus giving weight to their key role as intermediates in Friedel−Crafts reactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis, Crystal Structures and Electrical Conductivities of the Ionic Liquid Compounds Butyldimethylimidazolium Tetrafluoroborate, Hexafluorophosphate and Hexafluoroantimonate
Authors: Kölle Philipp , Dronskowski Richard
Published: July 2004

See original Eur. J. Inorg. Chem. 2004, 2313–2320 ( DOI: http://dx.doi.org/10.1002/ejic.200300940).
Molecular “Iron Maidens”: Ultrashort Nonbonded Contacts in Cyclophanes and Other Crowded Molecules
Authors: Pascal Robert A.
Published: July 2004

Ultrashort nonbonded interactions involving aromatic rings should be the sole province of cyclophane chemists, but it is not always so. In this review, the structures, syntheses, and properties of molecules exhibiting the closest nonbonded contacts of various atoms and functional groups with the faces of aromatic rings are discussed and illustrated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Catalytic Hydrogen‐Mediated Cross‐Coupling of Enones and Carbonyl Compounds: Aldol Condensation by Hydrogenation
Authors: Jang Hye‐Young , Krische Michael J.
Published: July 2004

Catalytic hydrogenation of enones and enals in the presence of aldehyde and ketone partners results in the formation of aldol products. A key feature of such hydrogen‐mediated C−C bond formations relates to the heterolytic activation of elemental hydrogen by cationic rhodium(I) complexes, that enables monohydride‐based catalytic cycles for which direct alkyl‐hydrogen reductive elimination pathways are disabled. Here, a concise overview of catalytic hydrogen‐mediated aldol condensation is presented. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Analysis of the Voltammetric Response of Electroactive Guests in the Presence of Non‐Electroactive Hosts at Moderate Concentrations
Authors: Mendoza Sandra , Castaño Eduardo , Meas Yunny , Godínez Luis A. , Kaifer Angel E.
Published: July 2004

In this work, we present a method to analyze the voltammetric response of reversible redox systems involving molecules that, bearing m non‐interactive electroactive sites, can undergo fast complexation equilibria with host molecules present at concentrations of the same order of magnitude as those of the electroactive guest. The approach focuses on systems for which the relative values of the binding constants for the oxidized and reduced forms of the guest result in the displacement of the voltammetric response of the electroactive molecule as the concentration of the host is increased in the electrolytic solution. This behavior is commonly known as “one wave shift behavior”. Based on a series of assumptions, the method allows calculation of all the thermodynamic parameters that describe the electrochemical and complexation equilibria of a given host‐guest system. The main strength of the suggested method, however, relies on the fact that it only requires cyclic voltammetry data and that it can be used for systems in which large concentrations of the host can not be employed either due to important changes of the ionic strength or to solubility problems. Although the accuracy of the obtained information is limited by the quality of the data provided by the technique, and by the assumptions employed, it certainly represents an excellent starting point for subsequent refinement either using digital simulations or an independent experimental technique.
Microdimensional Polyaniline: Fabrication and Characterization of Dynamics of Charge Propagation at Microdisk Electrodes
Authors: Caban Karolina , Kulesza Pawel J. , Stojek Zbigniew , Donten Mikolaj , Miecznikowski Krzysztof , Chojak Malgorzata
Published: July 2004

We describe fabrication of microdimensional polyanilne films in a controlled manner by voltammetric potential cycling or controlled potential electrolysis on platinum microdisk electrodes. The film grows in a form of hemispherical microdeposits, and its size largely exceeds the size of a Pt microdisk. Consequently, the film covers both the Pt substrate as well as the surrounding glass seal. Since the adhering polyaniline layer is conducting, the latter situation may lead to an increase in the effective electrode surface area. The lateral growth of polyaniline films outside the microdisk has also been demonstrated by performing diagnostic voltammetric experiments with use of a double microdisk set‐up in which independent polarization of each disk is feasible. Microelectrode‐based chronocoulometry, that involves an uncomplicated well‐defined reduction potential step starting from the emeraldine (conducting) form and ending at leucoemeraldine (nonconducting) form, yields (upon application of a sufficiently short pulse) a well‐defined linear response of charge versus square root of time that is consistent with the linear effective diffusion as the predominant charge propagation mechanism. When describing the system kinetics in terms of the effective (apparent) diffusion coefficient, we expect this parameter to be on the level of 10−8 cm2 s−1 or lower. The relative changes in dynamics of charge transport are discussed with respect to the polyaniline film loading, the size of microdisk electrode, expansion of the active electrode area, and the choice of electrolyte (strong acid) anion. The results are consistent with the view that when Pt microelectrode is modified with PANI deposit exceeding the size of the microdisk substrate, it behaves in a way as if its surface area is effectively much larger than the geometric area of Pt microdisk.
Electrochemical and Spectroelectrochemical Studies on Pyridoxine Hydrochloride Using a Poly(methylene blue) Modified Electrode
Authors: Tan Liang , Xie Qingji , Yao Shouzhuo
Published: July 2004

The electrochemical redox processes of pyridoxine hydrochloride (VB6) at a poly(methylene blue) film modified glass carbon electrode (PMBE) in a phosphate buffer solution (PBS, pH 8.0) were studied by cyclic voltammetry. The VB6 electrode reaction with quasi‐reversible characteristics was diffusion‐controlled at low scan rates and adsorption‐controlled at high scan rates. The anodic peak current positive to 0.6 V (vs. SCE) was found to be proportional to the concentration of VB6 in the range of 0.010 to 1.03 mg⋅mL−1 with a detection limit of 1.34 μg mL−1. Fluorescence and UV‐vis absorption spectroelectrochemical measurements suggest that the pyridine ring was not destroyed over the potential range from −0.8 to 1 V (vs. SCE), and the electrocatalytic generation of pyridoxal was anodically started at 0.57 V.
Biosensor for Hepatitis B Virus DNA PCR Product and Electrochemical Study of the Interaction of Di(2,2′‐bipyridine)osmium(III) with DNA
Authors: Zhao Hongtao , Ju Huangxian
Published: July 2004

The strategy for electrochemical detection of HBV DNA PCR product (181 bps) was designed by covalently immobilizing single‐stranded HBV DNA on preoxidized glassy carbon electrode surface. The immobilization of single stranded DNA was verified by AC impedance spectra. The following hybridization reaction on surface was evidenced by electrochemical methods using [Os(bpy)2Cl2]+ as an electroactive indicator. The interactions of [Os(bpy)2Cl2]+ with calf thymus single and double stranded DNA immobilized on preoxidized glassy carbon electrodes were studied. [Os(bpy)2Cl2]+ could bind preferentially to the duplex DNA by intercalating to base pairs. The intrinsic binding constant of [Os(bpy)2Cl2]+ with calf thymus DNA was calculated to be 1.21×104 M−1. Using [Os(bpy)2Cl2]+ as an electrochemical hybridization indicator, the HBV DNA sensor has been used to detect qualitatively target HBV DNA in solution with high sensitivity and selectivity.
Modelling quality of life variables with non‐parametric mixtures
Authors: Forcina Antonio , Bartolucci Francesco
Published: July 2004

We present a new methodology for modelling the joint distribution of ordered categorical variables with finite mixtures where hypotheses of interest may be expressed by linear equality and inequality constraints on the parameters. The connection with non‐parametric polytomousitem response theorymodels is outlined and an application to the quality of life of asthmatic patients is examined. An algorithm for constrained maximum likelihood estimation is described and an analysis of deviance table for hypotheses testing based on the asymptotic distribution of the likelihood ratio statistic is outlined. Copyright © 2004 John Wiley & Sons, Ltd.
Instrumental variables in Gaussian directed acyclic graph models with an unobserved confounder
Authors: Stanghellini Elena
Published: July 2004

We discuss the problem of identification of relevant parameters in a DAG model for Gaussian variables with one unobserved variable that acts as a counfounder. We first make explicit what we intend for identification and then discuss an example where a modified notion of instrumental variable renders a system with a confounder identifiable. Copyright © 2004 John Wiley & Sons, Ltd.
Environmental burden of disease: HRQoL and statistical perspectives
Authors: Kumar Sen Pranab
Published: July 2004

Environmental toxicity and pollution mingled with substandard sanitation and public health practice can lead to serious health problems. Some of these toxics can be identified and subjected to preventive measures but together with some other major factors they form the environmental burden of disease, more seriously in developing countries. As a result, in health related quality of life risk assessments, especially relating to cancer of various types, as well as chronic and intestinal diseases, we need to incorporate toxicology as well as environmental epidemiology. Statistical perspectives in this challenging task are appraised with special attention to the arsenite contamination of the groundwater problem. Copyright © 2004 John Wiley & Sons, Ltd.
A new index for longitudinal quality of life: modelling and estimation
Authors: Limnios N. , Mesbah M. , Sadek A.
Published: July 2004

In this work, a new index for longitudinal quality of life is proposed and statistically analyzed through discrete and continuous time Markov process models. Copyright © 2004 John Wiley & Sons, Ltd.
Combining information from different sources to estimate a common effect and use of multiple measurements for ecological assessment
Authors: Rao C. R.
Published: July 2004

A statistical analysis for combining information from different sources to estimate an unknown parameter is outlined. A new index is then proposed as a measure of the quality of the site. Copyright © 2004 John Wiley & Sons, Ltd.
Measurement and analysis of health related quality of life and environmental data
Authors: Mesbah Mounir
Published: July 2004

The definition (or construction) of variables and indicators, and the analysis of the evolution of their joint distribution between various populations, times and areas are generally two different, well separated steps of the work for a statistician in the field of environment and/or health related quality of life.

The first step generally deals with calibration and metrology of variables. Key words are measurement or scoring, depending on the area of application. Most of the time, the statistical methods used are exploratory. The kinds of models specified are generally structural: classical factorial analysis models or modern item response theory models. The second step is certainly more known by most inferential statisticians. Linear, generalized linear, time series and survival models are very useful models in this step, where the variables constructed in the first step are incorporated and their joint distribution with the other analysis variables (treatment group, time, duration of life, etc.) is investigated.

In this article, the simple strategy of separating the two steps is compared with the global strategy of defining and analysing a global model, including both the measurement and the analysis step. Copyright © 2004 John Wiley & Sons, Ltd.
Health related quality of life, environment, and regulation
Authors: Lachenbruch Peter A.
Published: July 2004

This article discusses prevalent and incident environmental events and how they might affect clinical trials. Inclusion of stratification by site and by event time is suggested as a possible method to remove some of the effects in the analysis. Published in 2004 John Wiley & Sons, Ltd.
Assessing lung cancer risk in railroad workers using a first hitting time regression model
Authors: Ting Lee Mei‐Ling , Whitmore G. A. , Laden Francine , Hart Jaime E. , Garshick Eric
Published: July 2004

This article examines the application of a first hitting time (FHT) model, using an operational time scale, to assess mortality risk differentials of the work environment. A major case application is presented that applies the model to three job categories of railroad workers. The data set involves a study of more than 50 000 workers with mortality assessed from 1959 to 1996. Lung cancer mortality was assessed because of a suspected link to diesel exhaust exposure. Based on a model that stipulates that death occurs when the disease state of a subject first hits a threshold value, the FHT model provides insights into factors influencing disease progression. In this application, in particular, the findings suggest that a job category in 1959 alters the risk of death from lung cancer. Copyright © 2004 John Wiley & Sons, Ltd.
Smooth non‐parametric estimation of the distribution function from balanced ranked set samples
Authors: Gulati Sneh
Published: July 2004

In certain sampling schemes, such as ranked set sampling, the observed data set can consist entirely of independent order statistics. A balanced ranked set sample consists of n independent cycles, in each of which the experimenter selects k random samples, each of size k. The recorded observation in sample r of cycle i is the rth order statistic, X(r). Stokes and Sager (1988) have shown that the empirical distribution function based on such samples is an unbiased estimate of the underlying distribution function and is more precise than the empirical distribution function calculated from a simple random sample of the same size. In this article, the properties of the empirical distribution function developed by Stokes and Sager (1988) are further investigated. In addition, a kernel‐type estimator of the distribution function is developed. For large n, the smooth estimator is shown to be consistent and asymptotically normal. Finally, small sample properties of the two estimators are investigated and compared via computer simulations. Copyright © 2004 John Wiley & Sons, Ltd.
Using inter‐event functions for bandwidth selection in disease incidence ratio estimation
Authors: Chadæuf J. , Lebond A. , Senoussi R.
Published: July 2004

We propose a distance based criterion to choose the optimal bandwidth for a non‐parametric kernel estimator of the mark probability of a non‐stationary bivariate location process. The selected bandwidth achieves the minimum standardized distance between the observed inter‐event distance distribution and its expectation under the estimated model. This selection principle is performed to map the intensity of the incidence ratio of a West‐Nile outbreak in the South of France. Copyright © 2004 John Wiley & Sons, Ltd.
Assessment of sediment trace metal level and biological quality of Rhumel river by using multivariate analysis
Authors: Afri‐Mehennaoui Fatima‐Zohra , Sahli Leila , Mehennaoui Smail
Published: July 2004

The aim of this article is to assess the level of trace metal contamination of sediment and to evaluate the environmental water quality based on the distribution of benthic organisms at stations along the Rhumel river and its principal tributary Boumerzoug river selected in urban areas (Constantine, Algeria). Fresh sediment samples and benthic organisms were collected from 10 sites on three occasions (December 2000, February 2001 and April 2001). Four trace metals—manganese (Mn), lead (Pb), chrome (Cr), and cadmium (Cd)—were measured in surface sediment and in the fauna using a flame or flameless atomic absorption spectrophotometer. In addition, chemical water parameters, pH, dissolved oxygen (DO), conductivity (EC) and sediment variables, pH, loss on ignition (LOI) and grain size were determined. The differences in species composition of the benthic community and the biotic index variation were used to reveal disturbance in watercourses.

Principal component analysis (PCA) was used to identify the relationship between the sediment variables, water chemistry and distribution of benthic invertebrate communities. The results of PCA indicate that there are several significant correlations between trace metals which suggest their common origin (anthropogenic or natural sources). Besides, the PCA results suggest the following trend: the biotic index, communities' distribution of macroinvertebrates and dissolved oxygen were unconnected to from both sediment and fauna trace metals concentrations. Copyright © 2004 John Wiley & Sons, Ltd.
New real‐value modal combination rules for non‐classically damped structures
Authors: Falsone Giovanni , Muscolino Giuseppe
Published: July 2004

A procedure is presented to determine new modal combination rules (both CQC and SRSS) for non‐classically damped structures. The procedure presented in this paper does not need the solution of any complex eigenvalue problem, in contrast to other methods found in the literature. Thus, the modal combination rules presented here are easily applicable, even by those engineers who are unaccustomed to using complex algebra. Moreover, these formulations show the further advantage of requiring the response spectra only for the target damping ratio value. So the use of approximated formulae, necessary for passing from the response spectrum with the target damping ratio value to other ones, is avoided. Copyright © 2004 John Wiley & Sons, Ltd.
Evaluation of site‐dependent constant‐damage design spectra for reinforced concrete structures
Authors: Panyakapo Phaiboon
Published: July 2004

An investigation on the validity of the conventional design approach known as constant displacement ductility is carried out. The hysteretic behaviour described by the Modified Takeda model is taken to represent the characteristics of reinforced concrete structural systems. The results presented in the form of seismic damage spectra indicate that the conventional design approach may not be valid because cumulative damage is excessively high. The inelastic design spectra based on the constant‐damage concept are proposed in terms of simplified expressions. The expressions are derived from constant‐damage design spectra computed by non‐linear response analysis for SDOF systems subjected to ground motions recorded on rock sites, alluvium deposits, and soft‐soil sites. The proposed expressions, which are dependent on the local soil conditions, are functions of target seismic damage, displacement ductility ratio and period of vibration. The seismic damage of structures that have been designed based on this new design approach is also checked by a design‐and‐evaluation approach. The results are found to be satisfactory. Copyright © 2004 John Wiley & Sons, Ltd.
Modeling discontinuous periodic conditional volatility: Evidence from the commodity futures market
Authors: Taylor Nicholas
Published: July 2004

This paper examines a wide variety of models that allow for complex and discontinuous periodic variation in conditional volatility. The value of these models (including augmented versions of existing models) is demonstrated with an application to high frequency commodity futures return data. Their use is necessary, in this context, because commodity futures returns exhibit discontinuous intraday and interday periodicities in conditional volatility. The former of these effects is well documented for various asset returns; however, the latter is unique amongst commodity futures returns, where contract delivery and climate are driving forces. Using six years of high‐frequency cocoa futures data, the results show that these characteristics of conditional return volatility are most adequately captured by a spline‐version of the periodic generalized autoregressive conditional heteroscedastic (PGARCH) model. This model also provides superior forecasts of future return volatility that are robust to variation in the loss function assumed by the user, and are shown to be beneficial to users of Value‐at‐Risk (VaR) models. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:805–834, 2004