bluuebunny/crossref_metadata_2025 huggingface dataset:
MALDI‐TOF mass spectrometry on cellulosic surfaces of fresh and photo‐aged di‐ and triterpenoid varnish resins
Authors: Scalarone Dominique , Duursma Marc C. , Boon Jaap J. , Chiantore Oscar
Published: November 2005

Matrix‐Assisted Laser Desorption/Ionization Time‐of‐Flight mass spectrometry (MALDI‐TOF‐MS) on cellulosic surfaces is shown to be a suitable method for examining highly oxidized terpenoids, which are otherwise too difficult to determine by other techniques. By crystallization of a 2,5‐dihydroxybenzoic acid (DHB) matrix and the sample solution on cellulose‐coated thin layer chromatography(TLC) plates, spectra with good signal/noise ratios are obtained and no significant interferences due to matrix ions or cluster ions were produced, at least not in the range ofm/zvalues of interest (>300 Da). The validity of the method was tested on natural di‐ and triterpenoid resins used as paint varnishes by Old Masters. The samples were analyzed before and after artificial light ageing. Di‐ and triterpenoid compounds, being very sensitive towards photo‐oxidation, were found as oxidized molecules even in the raw resins and in the unexposed varnish layers. Artificial ageing simulating window‐filtered daylight resulted in a stronger oxidation of the original terpenoids and the incorporation of up to six oxygen atoms per molecule could be demonstrated. Terpenoid dimers and their oxidation products were also detected. Copyright © 2005 John Wiley & Sons, Ltd.
A high‐pressure mass spectrometric and density functional theory investigation of the thermochemical properties and structure of protonated dimers and trimers of glycine
Authors: Raspopov Serguei A. , McMahon Terrance B.
Published: November 2005

A new modification of pulsed‐ionization high‐pressure mass spectrometry (PHPMS) has been used to perform equilibrium thermochemical studies for relatively nonvolatile biomolecules such as amino acids. Binding enthalpy and entropy changes have been measured for proton‐bound clusters of glycine, which are in good agreement with both theoretical (DFT) results of this work and a previous blackbody infrared dissociation experiment. Experimental data indicate that a number of conformers of the proton‐bound dimer of glycine may coexist in the explored temperature range (360–460 K). Several new, conceptually different isomers (two of them zwitterionic) have been found by DFT calculations, one of which is 7 kJ mol−1 lower in energy than the structure previously reported to be the energy minimum. Copyright © 2005 John Wiley & Sons, Ltd.
The role of synoptic‐scale circulation in the linkage between large‐scale ocean–atmosphere indices and winter surface climate in British Columbia, Canada
Authors: Stahl Kerstin , Moore R. Dan , Mckendry Ian G.
Published: December 2005

In much of North America, variables such as temperature, precipitation, snowpack and streamflow are modulated by modes of large‐scale ocean‐atmosphere variability such as the Pacific Decadal Oscillation (PDO), El Niño‐Southern Oscillation (ENSO) and the Pacific North American Pattern (PNA). In this study, we test the hypothesis that the influence of these modes on air temperature and precipitation in British Columbia (BC), Canada, can be explained in relation to changes in frequencies of synoptic‐scale circulation types. A catalogue of 13 circulation types was derived by classifying daily mean sea‐level pressure (MSLP) grids from 1948 to 2003. The grids cover BC and the North Pacific and were subjected to a standard pattern recognition algorithm employing principal component analysis followed by cluster analysis on the component scores. The circulation types are generally associated with distinctive patterns of precipitation and air temperature anomalies across BC. Multiple linear regressions for selected stations in BC using the type frequencies as predictors explain up to 75% of the variance of mean winter temperature and 65% of winter precipitation. The frequencies of most circulation types vary significantly between the different phases of ENSO, PDO and PNA in a manner consistent with the temperature anomalies associated with those modes and, to a lesser extent, with the more complex precipitation anomalies. In addition, however, average temperatures and precipitation amounts for some circulation types differ systematically between phases of ENSO and PDO. Subsequent analysis revealed distinct differences among ENSO and PDO phases in the upper‐level circulation patterns associated with some surface types. A major part of the teleconnections can be explained through variations in the frequencies of synoptic‐scale circulation types, but systematic within‐type variability, particularly with PDO and PNA, can additionally influence the surface climate. Copyright © 2005 Royal Meteorological Society.
The α‐effect in micelles: Nucleophilic substitution reaction of p‐nitrophenyl acetate with N‐phenylbenzohydroxamate ion
Authors: Ghosh Kallol K. , Vaidya Jyoti , Satnami Manmohan Lal
Published: November 2005

Pseudo‐first‐order rate constants have been determined for the nucleophilic substitution reactions of p‐nitrophenyl acetate with p‐chlorophenoxide (4‐ClC6H4O−) and N‐phenylbenzohydroxamate (C6H5CON(C6H5)O−) ions in phosphate buffer (pH 7.7) at 27°C. The effect of cationic, (CTAB, TTAB, DTAB), anionic (SDS), and nonionic (Brij‐35) surfactants has been studied. The kobs value increases upon addition of CTAB and TTAB. The effect of DTAB and other surfactants on the reaction is not very significant. The micellar catalysis and α‐effect shown by hydroxamate ion have been explained. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 38: 26–31, 2006
Effect of surfactant micelles on the kinetics of oxidation of D‐fructose by cerium(IV) in sulfuric acid medium
Authors: Kabir‐ud‐Din  , Ali Mohd. Sajid , Khan Zaheer
Published: November 2005

Kinetics of the oxidation of D‐fructose by cerium(IV) has been investigated both in the absence and presence of surfactants (cetyltrimethylammonium bromide, CTAB, and sodium dodecyl sulfate, SDS) in sulfuric acid medium. The reaction exhibits first‐order kinetics each in [cerium(IV)] and
[D‐fructose] and inverse first order in [H2SO4]. The Arrhenius equation is found to be valid for the reaction between 30–50°C. A detailed mechanism with the associated reaction kinetics is presented and discussed. While SDS has no effect, CTAB increases the reaction rate with the same kinetic behavior in its presence. The catalytic role of CTAB micelles is discussed in terms of the pseudophase model proposed by Menger and Portnoy. The association constant Ks that equals to 286 mol−1 dm3 is found for the association of cerium(IV) with the positive head group of CTAB micelles. The effect of inorganic electrolytes (Na2SO4, NaNO3, NaCl) has also been studied and discussed. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 38: 18–25, 2006
Towards the automatic analysis of 1H NMR spectra: Part 5. Confirmation of chemical structure with flow‐NMR
Authors: Griffiths Lee
Published: December 2005

A shift comparison procedure, which allows the use of flow spectra in automatic structure confirmation, is described. The effect of imperfect proton scaling at the analysis stage, loss of solute resonances under large solvent signals and the intermittent detection of labile protons are considered. The derivation of a suitable threshold acceptance criterion in the absence of explicit knowledge of spectral prediction reliability is also discussed.

The methodology yielded approximately 10–15% incorrect structure confirmation, but the exact number depends on the reliability of spectral prediction and the number of incorrect but closely related structures postulated. Copyright © 2006 John Wiley & Sons, Ltd.
Reverse atom‐transfer radical polymerization of acrylonitrile catalyzed by FeCl3/iminodiacetic acid
Authors: Hou Chen , Liu Junshen , Wang Chengguo
Published: November 2005

FeCl3 coordinated by iminodiacetic acid (IMA) was Changed used for the first time as the catalyst in azobisisobutyronitrile‐initiated reverse atom‐transfer radical polymerization (ATRP) of acrylonitrile (AN). An FeCl3 to IMA ratio of 1:2 not only gave the best control of molecular weight and its distribution but also provided a rather rapid reaction rate. The effects of solvents on the polymerization of AN were also investigated. The rate of the polymerization in N,N‐dimethylformamide (DMF) was faster than in propylene carbonate or toluene. The molecular weight of polyacrylonitrile agreed reasonably well with the theoretical molecular weight in DMF. The rate of polymerization increased with increasing polymerization temperature and the apparent activation energy was calculated to be 54.8 kJ mol−1. The reverse ATRP of AN did not show obvious living characteristics with CuCl2 instead of FeCl3. Copyright © 2005 Society of Chemical Industry
Rapid typing of Moraxella catarrhalis subpopulations based on outer membrane proteins using mass spectrometry
Authors: Schaller André , Troller Rolf , Molina Daniel , Gallati Sabina , Aebi Christoph , Stutzmann Meier Patricia
Published: November 2005

Moraxella catarrhalis is a major mucosal pathogen of the human respiratory tract both in children and in adults. Two subpopulations of this organism have been described that differ in 16S rRNA gene sequence and virulence traits. Three 16S rRNA types have been defined. 2‐DE followed by protein identification by MS revealed significant differences in the outer membrane protein (OMP) patterns of each M. catarrhalis 16S rRNA type. Approximately 130 features were detected on the 2‐DE map of each M. catarrhalis 16S rRNA type. However, only 50 features were expressed by all strains. Furthermore, direct profiling of isolated OMP using MALDI‐TOF MS resulted in a characteristic spectral fingerprint for each 16S rRNA type. Fingerprints remained identical when intact cells instead of isolated OMP were analyzed. This finding suggests that the source of desorbed ions is the outer membrane. Based on the fingerprint we were able to assign 18 well‐characterized clinical M. catarrhalis isolates to the correct subpopulation. Therefore, MALDI‐TOF of intact M. catarrhalis provides a rapid and robust tool for M. catarrhalis strain typing that could be applied in epidemiological studies.
Nonaqueous synthesis of nanosilica in epoxy resin matrix and thermal properties of their cured nanocomposites
Authors: Lee Tzong‐Ming , Ma Chen‐Chi M.
Published: November 2005

Nonaqueous synthesis of nanosilica in diglycidyl ether of bisphenol‐A epoxy (DGEBA) resin has been successfully achieved in this study by reacting tetraethoxysilane (TEOS) directly with DGEBA epoxy matrix, at 80 °C for 4 h under the catalysis of boron trifluoride monoethylamine (BF3MEA). BF3MEA was proved to be an effective catalyst for the formation of nanosilica in DGEBA epoxy under thermal heating process. FTIR and 29Si NMR spectra have been used to characterize the structures of nanosilica obtained from this direct thermal synthetic process. The morphology of the nanosilica synthesized in epoxy matrix has also been analyzed by TEM and SEM studies. The effects of both the concentration of BF3MEA catalyst and amount of TEOS on the diameters of nanosilica in the DGEBA epoxy resin have been discussed in this study. From the DSC analysis, it was found that the nanosilica containing epoxy exhibited the same curing profile as pure epoxy resin, during the curing reaction with 4,4′‐diaminodiphenysulfone (DDS). The thermal‐cured epoxy–nanosilica composites from 40% of TEOS exhibited high glass transition temperature of 221 °C, which was almost 50 °C higher than that of pure DGEBA–DDS–BF3MEA‐cured resin network. Almost 60 °C increase in thermal degradation temperature has been observed during the TGA of the DDS‐cured epoxy–nanosilica composites containing 40% of TEOS. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 757–768, 2006
Transition states for deactivation reactions in the modeled 2,2,6,6‐tetramethyl‐1‐piperidinyloxy‐mediated free‐radical polymerization of acrylonitrile
Authors: Kaim Andrzej , Megiel Elżbieta
Published: December 2005

The geometries and energetics of transition states (TS) for radical deactivation reactions, including competitive combination and disproportionation reactions, have been studied for the modeled 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO)‐mediated free‐radical polymerization of acrylonitrile with quantum mechanical calculations at the DFT/UB3‐LYP/6‐311+G(3df,2p)//(U)AM1 level of theory (where DFT is density functional theory, AM1 is Austin model 1, and UAM1 is unrestricted Austin model 1). A method providing reasonable starting geometries for an effective search for TS between the TEMPO radical and 1‐cyanopropyl radical mimicking the growing polyacrylonitrile macroradical is shown. For the hydrogen atom abstraction reaction by the TEMPO radical from the 1‐cyanopropyl radical, practically one TS has been found, whereas for the combination reaction of the radicals, several TS have been found, mainly differing in out‐of‐plane angle α of the NO bond in the TEMPO structure. α in the TS is correlated with the activation energy, ΔE, determined from the single‐point calculation at the DFT UB3‐LYP/6‐311+G(3df, 2p)//UAM1 level for the combination reaction of CH3AN· with the TEMPO radical. The theoretical activation energy for the coupling reaction from DFT UB3‐LYP/6‐311+G(3df, 2p)//UAM1 calculations has been estimated to be 11.6 kcal mol−1, that is, only about 4.5 times smaller than ΔE for the disproportionation reaction obtained with the DFT UB3‐LYP/6‐311+G(3df, 2p)//(U)AM1 approach. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 914–927, 2006
A contact mechanics method for characterizing the elastic properties and permeability of gels
Authors: Hui Chung‐Yuen , Lin Yu Yun , Chuang Fu‐Chin , Shull Kenneth R. , Lin Wei‐Chun
Published: November 2005

When a saturated gel immersed in the same liquid is suddenly brought into contact with a smooth rigid indenter, the liquid cannot immediately flow out of the pores, and so the gel initially behaves as an incompressible material. This gives rise to a pressure gradient in the liquid phase and the liquid flows until the pressure in it goes to zero everywhere, and all the stresses are transferred to the elastic network. As a result of the flow, the force needed to maintain a constant contact area relaxes with time. In this work, we study the feasibility of using an indentation test to measure this time‐dependent force and to determine the elastic modulus, the Poisson's ratio, and the permeability, Dp, of the network. Specifically, we consider a two‐dimensional Hertz contact problem of a rigid circular cylinder indenting on a half space consisting of an elastic gel. The network of the gel is assumed to be linearly elastic and isotropic, and liquid flow within the gel is assumed to obey Darcy's law, which states that the flux is proportional to the pressure gradient. Exact expressions are obtained for the initial and final force required to maintain a given contact length. These expressions allow us to determine the elastic constants of the network. The permeability of the network can be obtained from the time‐dependent relaxation of the load, which is obtained by solving the exact continuum equations. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 359–370, 2006
Exploiting sequence and structure homologs to identify protein–protein binding sites
Authors: Chung Jo‐Lan , Wang Wei , Bourne Philip E.
Published: December 2005

A rapid increase in the number of experimentally derived three‐dimensional structures provides an opportunity to better understand and subsequently predict protein–protein interactions. In this study, structurally conserved residues were derived from multiple structure alignments of the individual components of known complexes and the assigned conservation score was weighted based on the crystallographic B factor to account for the structural flexibility that will result in a poor alignment. Sequence profile and accessible surface area information was then combined with the conservation score to predict protein–protein binding sites using a Support Vector Machine (SVM). The incorporation of the conservation score significantly improved the performance of the SVM. About 52% of the binding sites were precisely predicted (greater than 70% of the residues in the site were identified); 77% of the binding sites were correctly predicted (greater than 50% of the residues in the site were identified), and 21% of the binding sites were partially covered by the predicted residues (some residues were identified). The results support the hypothesis that in many cases protein interfaces require some residues to provide rigidity to minimize the entropic cost upon complex formation. Proteins 2006. © 2005 Wiley‐Liss, Inc.
Solution structure of YggX: A prokaryotic protein involved in Fe(II) trafficking
Authors: Cui Qiu , Thorgersen Michael P. , Westler William M. , Markley John L. , Downs Diana M.
Published: December 2005

We report the three‐dimensional structure of YggX from Salmonella enterica, determined by solution nuclear magnetic resonance (NMR) spectroscopy from protein labeled with carbon‐13 and nitrogen‐15 produced by Escherichia coli cells. The protein has a β1β2α1α2α3 fold that is unique to YggX and one of its homologs, a protein from Pseudomonas aeruginosa with 45% sequence identity whose X‐ray structure [Protein Data Bank (PDB) 1T07] was determined by a structural genomics center. The NMR structure, which revealed that the C‐terminal region of YggX is dynamically disordered, explains why electron density from the corresponding region was missing in the X‐ray structure of the Pseudomonas protein. Because it has been hypothesized that YggX has a role in iron trafficking, we investigated the influence of Fe(II) on the 1H‐15N NMR fingerprint region of nitrogen‐15‐labeled YggX. Several signals shifted or broadened upon the addition of excess Fe(II) under anoxic conditions, with His81 showing the largest effect. These results indicate that Fe(II) binds weakly to this protein at a region of the sequence conserved only in the subset of the YggX proteins from organisms similar to Salmonella. The finding that iron binds only weakly to YggX, and not to a highly conserved region of the structure, suggests that the role of this protein in iron homeostasis is more complex than previously thought. Proteins 2006. © 2005 Wiley‐Liss, Inc.
Electronic structure and parity effects in correlated nanosystems
Authors: Rycerz Adam , Spałek Jozef
Published: December 2005

We discuss the spectral, transport and magnetic properties of quantum nanowires composed of N ≤ 13 atoms and containing either even or odd numbers of valence electrons. In our approach we combine Exact Diagonalization and Ab Initio calculations (EDABI method). The analysis is performed as a function of the interatomic distance. The momentum distribution differs drastically for those obtained for even N with those for odd N , whereas the Drude weight evolve smoothly. A role of boundary conditions is stressed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Frequency dependent mobility of charge carriers along polymer chains with finite length
Authors: Prins P. , Grozema F. C. , Schins J. M. , Siebbeles L. D. A.
Published: December 2005

The effect of the chain length of conjugated polymers on the real and imaginary components of the frequency dependent mobility of charge carriers is studied. A theoretical model for one‐dimensional diffusive motion of charges between reflecting chain ends is presented. It is shown that the model can be used to describe the measured ratio of the imaginary and real components of the microwave (30 GHz) mobility of charge carriers moving along ladder‐type polymer chains with different lengths. From comparison of theoretical and experimental data it is inferred that an intra‐chain mobility of 30 cm2/Vs can be achieved for ladder‐type polymer chains, which are sufficiently long so that chain ends do not limit the mobility. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interactions between aroma compounds and latex films: partition coefficients and influence on latex film formation
Authors: Nestorson A. , Leufvén A. , Järnström L.
Published: November 2005

The potential of various latex grades to take up, retain and release different types of aroma compound has been explored. The latex grades used included two styrene–acrylate latices and two styrene–butadiene latices, of which one contained talc. The aroma compounds used were ethyl butyrate, 1‐hexanol, heptanal, 3‐octanone, α‐pinene and limonene dissolved in propylene glycol. It was shown that talc improves both the uptake of aroma compounds in the dispersion phase and the retention during the film formation process. However, the styrene–acrylate latex had a greater ability than the styrene–butadiene latex to hold the aroma compounds once the films were formed. These results have been compared to calculated solubility parameters. The uptake of 1‐hexanol and propylene glycol in the latex dispersions were higher than expected from the theoretical calculations, probably because of the amphiphilic nature of these molecules. In addition, the influence of aroma compounds on the film formation was evaluated. Copyright © 2005 John Wiley & Sons, Ltd.
Allosteric Modulation of Family 3 GPCRs
Authors: Noeske Tobias , Gutcaits Aleksandrs , Parsons Christopher G. , Weil Tanja
Published: December 2005

This article reviews recent advances towards an understanding of the transmembrane structure, its activation and binding sites of family 3 G‐Protein‐Coupled Receptors (3‐GPCRs). First, the prediction of their 3D structureviahomology models based on the crystal structure of bovine rhodopsin will be discussed. Then, different kinetic mechanisms of ligand‐binding inside the heptahelical domain are presented before an overview of most common structural motifs of 3‐GPCR allosteric modulators will be given. Here, special focus lies in the characterization of their binding pocket within the transmembrane domain as well as their interaction with crucial amino acids. The overview of available mutation data inside the ligand‐binding domains as well as the influence of exchanged amino acids on the activity of different receptors leads to the question whether allosteric ligands of family 3 GPCRs bind to the same binding pocket and if there exists a common binding site of family 1 GPCRs and family 3 GPCRs.
Plant dispersal along rivers fragmented by dams
Authors: Merritt David M. , Wohl Ellen E.
Published: November 2005

To understand the influence of dams on connectivity of riparian plant communities along rivers, we examined plant dispersal by water (hydrochory) and riparian plant community attributes upstream and downstream from dams on two rivers in the southern Rocky Mountains, Colorado, USA. Drifting plant propagules were collected from the water column along reaches upstream and downstream from dams to examine the longitudinal and temporal variation in seed‐pool species composition and concentration of water‐transported seeds. Similarities between species composition of the hydrochoric seed pool and local standing riparian vegetation were used to evaluate the degree of longitudinal connectivity along river corridors and to isolate the relative contributions of local versus regional species pools to hydrochoric species composition. Furthermore, several synthetic attributes (longevity, origin, life‐form and dispersal mode) and species composition of riparian plant communities were examined to explore the effects of interrupted propagule dispersal on standing vegetation.

We estimated that as many as 120 million seeds were transported via hydrochory along free‐flowing reaches of the Rocky Mountain streams in a single growing season. Seed concentration (seeds/m3) in the water column was reduced by 70–94% along reaches downstream from dams compared to free‐flowing reaches. The similarity in species composition of hydrochoric seeds and local standing vegetation was nearly two times greater downstream from reservoirs compared to upstream. This suggests that hydrochory complements local species pools by importing seeds from throughout the upstream catchment area along free‐flowing river reaches, but that hydrochoric seeds are derived primarily from local sources along regulated river reaches. Species richness recovers as a function of downstream distance from contributions of standing vegetation and seeds from tributary streams. Hydrochory may extend the period over which viable seeds of a parent population are dispersed. Even after dispersal of parent populations has terminated, seeds may continue to be available due to residence time in water transport. This extension of the ‘effective dispersal window’ of some species may exceed two weeks or more and may influence the likelihood of successful establishment.

In this study, synthetic attributes of riparian vegetation did not differ significantly between free‐flowing and regulated reaches, whereas formal statistical comparisons of community composition upstream and downstream from reservoirs indicate that there are differences in community composition upstream and downstream from dams. These findings suggest that the consequences of 50 to 100 years of fragmentation result in community‐wide effects along Rocky Mountain streams and that these effects may be partially explained by dam‐caused disruption in connectivity of plant populations. Copyright © 2005 John Wiley & Sons, Ltd.
Accommodation of additional non‐randomly sampled cases in a study of Helicobacter pylori infection in families
Authors: Kivi Mårten , Johansson Anna L. V. , Salim Agus , Tindberg Ylva , Reilly Marie
Published: November 2005

Epidemiological studies with two‐stage designs typically gather information about some covariates from all study subjects in the first sampling stage, while additional data from only a subset of the subjects are collected in the second sampling stage. Appropriate analysis of two‐stage studies maintains validity and can also improve precision. We describe an application of a weighted likelihood method, mean‐score logistic regression, to accommodate data from a cross‐sectional study of Helicobacter pylori infection in children, where the study sample was enriched with additional non‐randomly sampled cases. The present work exemplifies how careful analysis of epidemiological data from complex sampling schemes can adjust for potential selection bias, improve precision and enable a more complete investigation of factors of interest. Our results highlight the importance of H. pylori infected mothers and siblings as risk factors for the infection in children in Sweden. Copyright © 2005 John Wiley & Sons, Ltd.
Modelling intervention effects after cancer relapses
Authors: González Juan R. , Peña Edsel A. , Slate Elizabeth H.
Published: November 2005

This article addresses the problem of incorporating information regarding the effects of treatments or interventions into models for repeated cancer relapses. In contrast to many existing models, our approach permits the impact of interventions to differ after each relapse. We adopt the general model for recurrent events proposed by Peña and Hollander, in which the effect of interventions is represented by an effective age process acting on the baseline hazard rate function. To accommodate the situation of cancer relapse, we propose an effective age function that encodes three possible therapeutic responses: complete remission, partial remission, and null response. The proposed model also incorporates the effect of covariates, the impact of previous relapses, and heterogeneity among individuals. We use our model to analyse the times to relapse for 63 patients with a particular subtype of indolent lymphoma and compare the results to those obtained using existing methods. Copyright © 2005 John Wiley & Sons, Ltd.
Re‐use of case–control data for analysis of new outcome variables
Authors: Reilly Marie , Torrång Anna , Klint Åsa
Published: November 2005

Case–control studies are usually defined to investigate risk factors for a single disease of interest. However, subsequent to data collection, investigators may wish to examine as an ‘outcome’ a variable that was an exposure in the original study. A naive analysis that disregards the sampling strategy that gave rise to the data is clearly prone to bias. We present here a simple approach to the analysis of such data using an appropriately weighted regression model. Viewing the problem as a two‐stage design provides a unified framework for recognizing and defining the necessary weights when confronted with a variety of real data problems that at first seem unrelated. We provide illustrations that highlight the generality of the approach and demonstrate that the method gives essentially the same results as more specialized methods that require non‐standard tools for analysis. Copyright © 2005 John Wiley & Sons, Ltd.
Eliciting and using expert opinions about influence of patient characteristics on treatment effects: a Bayesian analysis of the CHARM trials
Authors: White Ian R. , Pocock Stuart J. , Wang Duolao
Published: November 2005

When randomized trial results are available for several different groups of patients, neither applying the overall results to each type of patient nor using group‐specific results is entirely satisfactory. Instead, we estimate group‐specific treatment effects using a Bayesian approach with informative priors for the treatment × group interactions. We describe how we elicited these prior beliefs about the effects of a new drug for the treatment of heart failure in three different patient groups. Using results from three trials, one in each patient group, the posterior mean treatment effects are very similar to the trial‐specific maximum likelihood estimates, showing that in this case each trial effectively stands by itself. Our methods can also be applied to subgroup analyses in a single clinical trial, where subgroup‐specific posterior means are likely to lie between the subgroup‐specific maximum likelihood estimates and the pooled maximum likelihood estimates. Copyright © 2005 John Wiley & Sons, Ltd.
Prenatal diagnosis of thrombosed aneurysm of vein of Galen
Authors: Vijayaraghavan S. Boopathy , Vijay S. , Kala M. R. , Neha D.
Published: November 2005

Aneurysm of the vein of Galen in the fetus is a rare malformation that has been described in a small number of case reports. Thrombosis of aneurysm of the vein of Galen is a rare occurrence reported in postnatal cases. We report a case of thrombosis of vein of Galen aneurysm occurring in a fetus of 21 weeks' gestation. The fetus showed an echogenic mass posterior and superior to the thalamus. It also showed dilated dural venous sinuses, dilated neck vessels, cardiomegaly and minimal ascites. The pregnancy was terminated and autopsy confirmed the diagnosis. The present case is the first report of the prenatal sonographic features of this condition in the literature. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Fluor‐Kohlenstoff‐Nanoschichten zur gezielten Oberflächenfunktionalisierung. Fluorine‐Carbon Nano Coatings for Specific Surface Functionalization
Authors: Haupt Michael , Barz Jakob , Vohrer Uwe , Hilgers Heinz , Oehr Christian
Published: November 2005

Der Artikel beschreibt einige Aspekte aus den Entwicklungs‐ und Forschungsarbeiten, die im Rahmen des BMBF Projektes “Nano‐Funktionalisierung von Grenzflächen für Daten‐, Textil‐, Gebäude‐, Medizin‐, Bio‐, und Raumfahrttechnik” durchgeführt werden. Es wird auf die verschiedenen, breit gefächerten Anwendungsgebiete von plasmamodifizierten Oberflächen eingegangen und ein Überblick über die Charakterisierungsmethoden an den Schichten gegeben.

Mit Hilfe der Niederdruck‐Plasmatechnologie lassen sich Oberflächen physikalisch‐chemisch funktionalisieren und gezielt auf ihre Anwendung anpassen, ohne die Grundeigenschaften des Volumenmaterials zu verändern. Die Oberflächen der zu modifizierenden Werkstücke werden in einem Plasmaprozess mit einer ultra dünnen, d.h. nur wenige Nanometer dicken Fluor‐Kohlenstoff‐Polymerschicht beschichtet. Die physikalisch‐chemischen Eigenschaften der Oberflächen, wie z.B. die Oberflächenenergie, die Rauheit (auf der Nanometerskala), das dynamische Benetzungsverhalten oder die Adhäsionseigenschaft gegenüber anderen Materialien lassen sich durch Veränderung der Plasmaprozessparameter einstellen. Es wird gezeigt, dass diese Art der Oberflächenmodifizierung in Zukunft ein breites Anwendungsfeld eröffnet.
A comparison of self‐reported puberty using the Pubertal Development Scale and the Sexual Maturation Scale in a school‐based epidemiologic survey
Authors: Bond Lyndal , Clements Jackie , Bertalli Nadine , Evans‐Whipp Tracy , McMorris Barbara J. , Patton George C. , Toumbourou John W. , Catalano Richard F.
Published: December 2005

Purpose

To examine concordance between two self‐reported measures of puberty: Sexual Maturation Scale (SMS) and Pubertal Development Scale (PDS) and their acceptability to adolescents.

Methods

Participants of a school‐based study in grades 5, 7 and 9 were classified into one of 5 pubertal stages using each method.

Results

2864 students (age 9–16 years) participated. Agreement was moderate for males ( 0.42, 95% CI 0.39, 0.45) and females ( 0.57, 95% CI 0.53, 0.61). Concordance within one stage was excellent (females 97%, males 89%), with discrepancies due to females being classified one stage later on the PDS (26%) and males one stage earlier (32%). There were more missing data for the SMS (13%) than the PDS (4%).

Conclusions

Given the level of concordance and difficulties of using the drawings in a school‐based survey, we would recommend the PDS as an alternative to assess pubertal status in epidemiological studies.
Ethanol increases mitochondrial cytochrome P450 2E1 in mouse liver and rat hepatocytes
Authors: Robin Marie-Anne , Sauvage Ingrid , Grandperret Thomas , Descatoire Véronique , Pessayre Dominique , Fromenty Bernard
Published: December 2005

Enhanced hepatic levels of cytochrome P450 2E1 (CYP2E1) may play a key role in the pathogenesis of some liver diseases because CYP2E1 represents a significant source of reactive oxygen species. Although a large fraction of CYP2E1 is located in the endoplasmic reticulum, CYP2E1 is also present in mitochondria. In this study, we asked whether ethanol, a known inducer of microsomal CYP2E1, could also increase CYP2E1 within mitochondria. Our findings indicated that ethanol increased microsomal and mitochondrial CYP2E1 in cultured rat hepatocytes and in the liver of lean mice. This was associated with decreased levels of glutathione, possibly reflecting increased oxidative stress. In contrast, in leptin‐deficient obese mice, ethanol administration did not increase mitochondrial CYP2E1, nor it depleted mitochondrial glutathione, suggesting that leptin deficiency hampers mitochondrial targeting of CYP2E1. Thus, ethanol intoxication increases CYP2E1 not only in the endoplasmic reticulum but also in mitochondria, thus favouring oxidative stress in these compartments.
The structures of MsbA: Insight into ABC transporter‐mediated multidrug efflux
Authors: Reyes Christopher L. , Ward Andrew , Yu Jodie , Chang Geoffrey
Published: December 2005

ATP‐binding cassette (ABC) transporters are integral membrane proteins that couple ATP hydrolysis to the transport of various molecules across cellular membranes. Found in both prokaryotes and eukaryotes, a sub‐group of these transporters are involved in the efflux of hydrophobic drugs and lipids, causing anti‐microbial and chemotherapeutic multidrug resistance. In this review, we examine recent structural and functional analysis of the ABC transporter MsbA and implications on the mechanism of multidrug efflux.
Isolated ε subunit of Bacillus subtilis F1‐ATPase binds ATP
Authors: Kato-Yamada Yasuyuki
Published: December 2005

Previously, we demonstrated ATP binding to the isolated ε subunit of F1‐ATPase from thermophilic Bacillus PS3 [Kato‐Yamada Y., Yoshida M. (2003) J. Biol. Chem. 278, 36013]. However, whether it is a general feature of the ε subunit from other sources is yet unclear. Here, using a sensitive method to detect weak interactions between fluorescently labeled ε subunit and nucleotide, it was shown that the ε subunit of F1‐ATPase from Bacillus subtilis also bound ATP. The dissociation constant for ATP binding at room temperature was calculated to be 2 mM, which may be suitable for sensing cellular ATP concentration in vivo.
Dissection of Escherichia coli glutamate 5‐kinase: Functional impact of the deletion of the PUA domain
Authors: Pérez-Arellano Isabel , Rubio Vicente , Cervera Javier
Published: December 2005

Glutamate 5‐kinase (G5K) catalyzes the controlling first step of the synthesis of the osmoprotective amino acid proline, which feed‐back inhibits G5K. Microbial G5K generally consists of one amino acid kinase (AAK) and one PUA (named after pseudo uridine synthases and archaeosine‐specific transglycosylases) domain. To investigate the role of the PUA domain, we have deleted it from Escherichia coli G5K. We show that wild‐type G5K requires free Mg for activity, it is tetrameric, and it aggregates to higher forms in a proline‐dependent way. G5K lacking the PUA domain remains tetrameric, active, and proline‐inhibitable, but the Mg requirement and the proline‐triggered aggregation are greatly diminished and abolished, respectively, and more proline is needed for inhibition. We propose that the PUA domain modulates the function of the AAK domain, opening the way to potential PUA domain‐mediated regulation of G5K; and that this domain moves, exposing new surfaces upon proline binding.
Biochemical characterization of human kallikrein 8 and its possible involvement in the degradation of extracellular matrix proteins
Authors: Rajapakse Sanath , Ogiwara Katsueki , Takano Naoharu , Moriyama Akihiko , Takahashi Takayuki
Published: December 2005

Human kallikrein 8 (KLK8) is a member of the human kallikrein gene family of serine proteases, and its protein, hK8, has recently been suggested to serve as a new ovarian cancer marker. To gain insights into the physiological role of hK8, the active recombinant enzyme was obtained in a pure state for biochemical and enzymatic characterizations. hK8 had trypsin‐like activity with a strong preference for Arg over Lys in the P1 position, and its activity was inhibited by typical serine protease inhibitors. The protease degraded casein, fibronectin, gelatin, collagen type IV, fibrinogen, and high‐molecular‐weight kininogen. hK8 also converted human single‐chain tissue‐type plasminogen activator (65 kDa) to its two‐chain form (32 and 33 kDa) by specifically cleaving the peptide bond Arg275–Ile276. This conversion resulted in a drastic increase in the activity of the activator toward the fluorogenic substrate Pyr‐Gly‐Arg‐MCA and plasminogen in the absence of fibrin. Our findings suggest that hK8 may be implicated in ECM protein degradation in the area surrounding hK8‐producing cells.
Upstream migration and reproductive patterns of a population of allis shad in a small river (L'Aulne, Brittany, France)
Authors: Acolas M.L. , Véron V. , Jourdan H. , Bégout M.L. , Sabatié M.R. , Baglinière J.L.
Published: December 2005

The characteristics and activity of adult allis shad [Alosa alosa (L.)] were analysed during the last part of their upstream migration in the L'Aulne, a small river in Brittany, and during reproduction on a unique spawning ground downstream of an insurmountable dam. The age of the spawners ranged from three to seven years, females being larger and older than males. Population-level migration and reproduction were studied by counting the number of migrating fish, by estimating the sex ratio, and by counting the number of nocturnal spawning acts for three consecutive years starting in 2000. The influence of the environment, especially water temperature and discharge, was highlighted: temperature during migration may supplant the influence of water flow, although high flow could allow passage over the dam. Such factors partly explain the annual pattern of migration and reproduction during the spawning season. The study showed that the biological features and characteristics of this population of allis shad in a small river were similar to those of western Atlantic stocks in large rivers.
Home monitoring of the diabetic cat
Authors: Reusch Claudia E. , Kley Saskia , Casella Martina
Published: December 2005

Many owners are able and willing to perform home monitoring of blood glucose concentrations in diabetic cats. Once owners are familiar with the technique, they appreciate its advantages and show long-term compliance. The success of home monitoring hinges greatly on careful preparation and instruction of the owner. Owners must have ready access to veterinary support if needed. Initially, most owners call for advice, and several of them need repeated explanation or demonstration of the procedure. The frequency of re-evaluations of the diabetic cats by veterinarians is not affected by home monitoring. One of its major advantages is that it enables frequent generation of blood glucose curves. In complicated cases, more than one curve can, therefore, be performed at home before a treatment decision is made. According to preliminary data cats managed with home monitoring may have better glycaemic control than those managed without. However, those results need to be confirmed in a large group of cats.
An Immunohistochemical Study of Palmar and Plantar Digital Nerves
Authors: AUPLISH S. , HALL S.
Published: November 2005

We present a qualitative and semi-quantitative description of palmar and plantar digital nerves obtained from cadavers prepared for routine class dissection. The fingertips of the three most functionally important and sensitive digits, namely thumb, index and middle fingers, received more myelinated axons than those of the ring and little fingers. In both palmar and plantar nerves the numbers of myelin basic protein (MBP)-positive myelinated axons decreased proximodistally along each digit and also from thumb to little finger and hallux to little toe respectively. Our results suggest that there are up to ten times more myelinated axons in palmar digital nerves than in plantar nerves.
Carpal Boss: Destabilization of the third Carpometacarpal Joint after a Wedge Excision
Authors: CITTEUR J. M. E. , RITT M. J. P. F. , BOS K. E.
Published: November 2005

In a standard carpal boss procedure, the dorsal ligament of the involved carpometacarpal joint is cut in the process of performing a wedge excision. We studied the effect of such a dorsal ligament sectioning on the joint between the capitate and middle metacarpal bone in ten fresh-frozen wrist specimens. The passive range of motion of this joint was measured with the joint loaded into flexion and extension and in the unloaded neutral position. After the dorsal ligament of the carpometacarpal joint was cut, simulating a dorsal wedge excision, the passive range of motion was measured again. Analysis indicated that this simulated wedge excision approximately doubled the passive range of motion of the carpometacarpal joint. This study shows that such a procedure disturbs the normal anatomy and creates instability of the involved joint.
A Cheap, Disposable External Fixator for Comminuted Phalangeal Fractures
Authors: GODWIN Y. , ARNSTEIN P. M.
Published: November 2005

Reduction of a severely comminuted fracture of a long bone in the hand can be difficult to hold. An external fixator can be the best method of maintaining satisfactory reduction in such fractures. A small, disposable external fixator is described, made from a syringe barrel and K-wires. It allows accurate reduction with minimal soft tissue trauma and is easy to construct and apply. It allows early mobilization of the digit and is inexpensive.
Pregnancy-Related Carpal Tunnel Syndrome
Authors: SEROR P.
Published: November 2005

Clinical and electrophysiological features were studied in 52 cases of carpal tunnel syndrome (CTS) associated with 30 pregnancies. The duration of symptoms was less than 3 months before electrodiagnosis was performed. This study revealed a higher incidence of persistent, painful diurnal symptoms in pregnancy-related CTS (PRCTS) than in idiopathic CTS. PRCTS usually occurs for the first time (de novo) (24/30 cases), in primigravidas (15 cases) as well as multigravidas. The onset of symptoms was in the first or second trimester in 11 women, the third trimester in 12 women, or the post-partum period in seven women. Nerve conduction studies demonstrated evidence of an acute median nerve lesion at the wrist with motor and/or sensory conduction blocks in 20/30 women and severe denervation signs in five women.
Recurrent Anterior Interosseous Nerve Palsies Related to Pregnancy
Authors: BRUSSÉ C. A. , BURKE F. D.
Published: November 2005

A rare association of anterior interosseous nerve palsy with pregnancy has been reported previously ( Sood and Burke, 1997 ). We report further on this patient who has now experienced three separate anterior interosseous nerve palsies associated with pregnancies.
Intracapsular Chondroma of the Elbow Producing a Posterior Interosseous Nerve Palsy
Authors: MADHAVAN P. , LESLIE I. J.
Published: November 2005

We present a case report of a patient who presented with posterior interosseous nerve paralysis caused by an intracapsular chondroma arising within the elbow joint. We review the literature and discuss problems associated with making the diagnosis preoperatively.
Acute Median Nerve Injury due to Migration of a Kirschner Wire
Authors: JOU I-M. , LAI K-A.
Published: November 2005

Migration of orthopaedic implants such as K-wires is not unusual, but migration due to an improperly constructed brace has not been reported. This report describes such a mechanism in a case complicated by acute median nerve injury.
Reversed Palmaris Longus Muscle Causing Effort-Related Median Nerve Compression
Authors: DEPUYDT K. H. , SCHUURMAN A. H. , KON M.
Published: November 2005

Two cases of effort-related distal median nerve compression in the dominant forearm caused by a reversed palmaris longus muscle are presented. Simple resection of the muscle belly was performed. Carpal tunnel release was done in one case, but in retrospect this was probably not necessary.
Re-Growth of a Phalanx Following Removal for Infection in a Child
Authors: KENDALL S. J. H. , FERRIS B.
Published: November 2005

We report the re-growth of a distal phalanx of an index finger in a child following removal of the distal phalangeal diaphysis for infection.
An over-pressure correction to the slug model for vortex ring circulation
Authors: KRUEGER PAUL S.
Published: December 2005

The slug model provides a formula for the circulation of vortex rings formed by starting jets ejected from a nozzle or orifice in terms of the time history of the jet velocity. For rapidly initiated jets, however, the model under-predicts circulation by an amount that remains nearly constant as circulation increases. To remedy this shortcoming, the present study derives an equation for circulation directly from the governing equations for the flow, illustrating that the circulation can be expressed as the sum of a flux term, $\Gamma_U$, determined by the jet centreline velocity and a ‘source’ term, $\Gamma_p$, determined by over-pressure at the jet centreline during vortex ring formation. For impulsively or nearly impulsively initiated jets, $\Gamma_p$ is modelled using potential flow analysis since over-pressure is significant primarily during the rapid jet initiation in these cases. The effects of the jet initiation and boundary-layer growth on the jet centreline velocity are also considered to provide a realistic model for $\Gamma_U$. Models for nozzle and orifice configurations are developed. In the case of a nozzle-type generator, the need to model the jet centreline velocity leads to an approximate solution for starting flow near the exit of an infinitely long pipe. For the nozzle case, the model results agree with available circulation measurements to within ${\pm}$6.2% for a wide range of conditions, except for jet velocity programs that are nearly triangular. In the orifice case, the model agrees with available results to within ${-}$13%. Both cases show substantial improvement over the slug model, which is in error by ${-}$21% to ${-}$67% for the data considered.