bluuebunny/crossref_metadata_2025 huggingface dataset:
Tandem mass spectrometry of electrosprayed polyhedral oligomeric silsesquioxane compounds with different substituents
Authors: Fouquet Thierry , Phan Trang N. T. , Charles Laurence
Published: February 2012

RATIONALE

Polyhedral oligomeric silsesquioxanes (POSSs), defined as [RSiO3/2]n with R designating an organic substituent, were considered here as models of highly cross‐linked polysiloxanes, to be further used as references in tandem mass spectrometric characterization of plasma polymers of hexamethyldisiloxane, expected to be composed of organic polydimethylsiloxane (PDMS) and inorganic (SiOx) silica‐based parts. The collision‐induced dissociation (CID) behavior of [RSiO3/2]8 compounds was then studied as a function of the R substituent.

METHODS

POSS compounds were produced in the gas phase as ammonium adducts and the product ions generated upon CID, amongst which was the protonated precursor, were accurately mass measured in an orthogonal acceleration time‐of‐flight mass analyzer.

RESULTS

The presence of eight propylamine substituents was shown to induce sequential dehydration of the protonated precursor, ultimately leading to a complete unfolding of the POSS cage. Similar opening of the octahedron structure in the protonated molecule substituted with OSi(CH3)3, OSiH(CH3)2 or OH (formed upon methanolysis of dimethylsiloxy substituents) was proposed to account for the product ions generated during their CID. Sequential charge‐remote transfers of a methyl group (and of H in the case of dimethylsiloxy substituents) from one substituent group to a neighboring one was shown to lead to a linear co‐oligomeric chain composed of randomly distributed siloxy‐based monomers.

CONCLUSIONS

All the peaks observed in CID could be accounted for by applying dissociation reactions typically occurring in protonated polysiloxane‐like oligomers. The large number of product ions observed in MS/MS was found to result from the variety of possible structural rearrangements, producing numerous linear isomeric forms of the dissociating species. Copyright © 2012 John Wiley & Sons, Ltd.
Thermal decomposition of pyridoxine: an evolved gas analysis‐ion attachment mass spectrometry study
Authors: Juhász Márta , Takahashi Seiji , Kitahara Yuki , Fujii Toshihiro
Published: February 2012

RATIONALE

Pyridoxine is an important vitamer in food and pharmaceutical products. Heat treatments applied during preparation or storage of the products cause the decomposition of pyridoxine. Identification and understanding of the degradation products of pyridoxine and studying its decomposition kinetics are essential in the preparation and preservation of pyridoxine‐containing foods and pharmaceuticals.

METHODS

Real‐time, non‐isothermal decomposition of pyridoxine was studied using evolved gas analysis‐Li+ ion attachment mass spectrometry (EGA‐Li+IAMS). Arrhenius parameters for the thermal decomposition of pyridoxine were obtained via the total ion monitoring (TIM) curve.

RESULTS

Most of the pyridoxine evaporated in molecular form, but the formation of pyridoxal and o‐quinone methide, both biologically important species, was also observed from the solid‐phase degradation of pyridoxine. The observation of o‐quinone methide, a species possessing anticancer activity, was particularly noteworthy due to its chemical instability. The activation energy (Ea) for pyridoxine decomposition determined by EGA‐IAMS was found to be 20.0 kcal mol–1, and the pre‐exponential factor (A) was 5.7 × 109 min–1.

CONCLUSIONS

The calculated kinetic parameters are important for predicting the thermal stability of pyridoxine vitamer. The estimated lifetime (t90%,25°C) of 1.7 × 10–2 years in nitrogen was also obtained from the EGA‐IAMS experiment. Copyright © 2012 John Wiley & Sons, Ltd.
Molecular phylogenetics by direct comparison of tandem mass spectra
Authors: Palmblad Magnus , Deelder André M.
Published: February 2012

RATIONALE

Molecular phylogenetics is the study of evolution and relatedness of organisms or genes. Mass spectrometry is used routinely for bacterial identification and has also been used for phylogenetic analysis, for instance from bone material. Unfortunately, only a small fraction of the acquired tandem mass spectra allow direct interpretation.

METHODS

We describe a new algorithm and software for molecular phylogenetics using pairwise comparisons of tandem mass spectra from enzymatically digested proteins. The spectra need not be annotated and all acquired data is used in the analysis. To demonstrate the method, we analyzed tryptic digests of sera from four great apes and two other primates.

RESULTS

The distribution of spectra dot products for thousands of tandem mass spectra collected from two samples provides a measure on the fraction of shared peptides between the two samples. When inverted, this becomes a distance metric. By pairwise comparison between species and averaging over four individuals per species, it was possible to reconstruct the unique correct phylogenetic tree for the great apes and other primates.

CONCLUSIONS

The new method described here has several attractive features compared with existing methods, among them simplicity, the unbiased use of all acquired data rather than a small subset of spectra, and the potential use of heavily degraded proteins or proteins with a priori unknown modifications. Copyright © 2012 John Wiley & Sons, Ltd.
Determination of glycation sites by tandem mass spectrometry in a synthetic lactose‐bovine serum albumin conjugate, a vaccine model prepared by dialkyl squarate chemistry
Authors: Jahouh Farid , Hou Shu‐jie , Kováč Pavol , Banoub Joseph H.
Published: February 2012

RATIONALE

Neoglycoconjugate vaccines synthesized by the squaric acid spacer method allow single point attachment of the carbohydrate antigen to the protein carrier. However, the localization of the carbohydrate antigen sites of conjugation on the protein carrier has been an elusive task difficult to achieve.

METHOD

Covalent attachment of the lactose antigen to the bovine serum albumin (BSA) was prepared by the squaric acid method using a hapten:BSA ratio of 20:1. Different reaction times were used during the conjugation reaction and two different lactose‐BSA glycoconjugate vaccines were obtained. The carbohydrate antigen hapten:BSA ratios of these lactose‐BSA glycoconjugate vaccines were determined by MALDI‐TOF/RTOF‐MS and the glycation sites in the neoglycoconjugates were determined using nano‐LC/ESI‐QqTOF‐MS/MS analysis of the trypsin and GluC V8 digests of the conjugates.

RESULTS

We have identified a total of 15 glycation sites located on the BSA lysine residues for the neoglycoconjugate vaccine formed with a hapten:BSA ratio of 5.1:1, However, the tryptic and GluC V8 digests of the hapten‐BSA glycoconjugate with a hapten:BSA ratio of 19.0:1 allowed identification of 30 glycation sites located on the BSA. These last results seem to indicate that this conjugation results in formation of various glycoforms.

CONCLUSIONS

It was observed that the number of identified glycation sites increased when the hapten:BSA ratio of glycoconjugate formation increased, and that the location of the glycation sites appears to be mainly on the outer surface of the BSA carrier molecule which is in line with the assumption that the sterically more accessible lysine residues, namely those located on the outer surface of the BSA, would be conjugated preferentially. Copyright © 2012 John Wiley & Sons, Ltd.
SIR epidemics on random graphs with a fixed degree sequence
Authors: Bohman Tom , Picollelli Michael
Published: February 2012

Let Δ > 1 be a fixed positive integer. For\documentclass{article}\usepackage{mathrsfs}\usepackage{amsmath, amssymb}\pagestyle{empty}\begin{document}\begin{align*}{\textbf{ {z}}} \in \mathbb{R}_+^\Delta\end{align*} \end{document}letGzbe chosen uniformly at random from the collection of graphs on ∥z∥1nvertices that havezinvertices of degreeifori= 1,…,Δ. We determine the likely evolution in continuous time of the SIR model for the spread of an infectious disease onGz, starting from a single infected node. Either the disease halts after infecting only a small number of nodes, or an epidemic spreads to infect a linear number of nodes. Conditioning on the event that more than a small number of nodes are infected, the epidemic is likely to follow a trajectory given by the solution of an associated system of ordinary differential equations. These results also give the likely number of nodes infected during the course of the epidemic and the likely length in time of the epidemic. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 2012
Statistical properties of subgroups of free groups
Authors: Bassino Frédérique , Martino Armando , Nicaud Cyril , Ventura Enric , Weil Pascal
Published: February 2012

The usual way to investigate the statistical properties of finitely generated subgroups of free groups, and of finite presentations of groups, is based on the so‐called word‐based distribution: subgroups are generated (finite presentations are determined) by randomly chosen k ‐tuples of reduced words, whose maximal length is allowed to tend to infinity. In this paper we adopt a different, though equally natural point of view: we investigate the statistical properties of the same objects, but with respect to the so‐called graph‐based distribution, recently introduced by Bassino, Nicaud and Weil. Here, subgroups (and finite presentations) are determined by randomly chosen Stallings graphs whose number of vertices tends to infinity. Our results show that these two distributions behave quite differently from each other, shedding a new light on which properties of finitely generated subgroups can be considered frequent or rare. For example, we show that malnormal subgroups of a free group are negligible in the graph‐based distribution, while they are exponentially generic in the word‐based distribution. Quite surprisingly, a random finite presentation generically presents the trivial group in this new distribution, while in the classical one it is known to generically present an infinite hyperbolic group. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 2013
The forgetfulness of balls and bins
Authors: Perkins Will
Published: February 2012

We find the asymptotic total variation distance between two distributions on configurations of m balls in n labeled bins: in the first, each ball is placed in a bin uniformly at random; in the second, k balls are planted in an arbitrary but fixed arrangement and the remaining m ‐ k balls placed uniformly at random. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 2012
Sample size determination for quadratic inference functions in longitudinal design with dichotomous outcomes
Authors: Hu Youna , Song Peter X.‐K.
Published: February 2012

Quadratic inference functions (QIF) methodology is an important alternative to the generalized estimating equations (GEE) method in the longitudinal marginal model, as it offers higher estimation efficiency than the GEE when correlation structure is misspecified. The focus of this paper is on sample size determination and power calculation for QIF based on the Wald test in a marginal logistic model with covariates of treatment, time, and treatment–time interaction. We have made three contributions in this paper: (i) we derived formulas of sample size and power for QIF and compared their performance with those given by the GEE; (ii) we proposed an optimal scheme of sample size determination to overcome the difficulty of unknown true correlation matrix in the sense of minimal average risk; and (iii) we studied properties of both QIF and GEE sample size formulas in relation to the number of follow‐up visits and found that the QIF gave more robust sample sizes than the GEE. Using numerical examples, we illustrated that without sacrificing statistical power, the QIF design leads to sample size saving and hence lower study cost in comparison with the GEE analysis. We conclude that the QIF analysis is appealing for longitudinal studies. Copyright © 2012 John Wiley & Sons, Ltd.
Using R and WinBUGS to fit a generalized partial credit model for developing and evaluating patient‐reported outcomes assessments
Authors: Li Yuelin , Baser Ray
Published: February 2012

The US Food and Drug Administration recently announced the final guidelines on the development and validation of patient‐reported outcomes (PROs) assessments in drug labeling and clinical trials. This guidance paper may boost the demand for new PRO survey questionnaires. Henceforth, biostatisticians may encounter psychometric methods more frequently, particularly item response theory (IRT) models to guide the shortening of a PRO assessment instrument. This article aims to provide an introduction on the theory and practical analytic skills in fitting a generalized partial credit model (GPCM) in IRT. GPCM theory is explained first, with special attention to a clearer exposition of the formal mathematics than what is typically available in the psychometric literature. Then, a worked example is presented, using self‐reported responses taken from the international personality item pool. The worked example contains step‐by‐step guides on using the statistical languages r and WinBUGS in fitting the GPCM. Finally, the Fisher information function of the GPCM model is derived and used to evaluate, as an illustrative example, the usefulness of assessment items by their information contents. This article aims to encourage biostatisticians to apply IRT models in the re‐analysis of existing data and in future research. Copyright © 2012 John Wiley & Sons, Ltd.
Optimal allocation of participants for the estimation of selection, preference and treatment effects in the two‐stage randomised trial design
Authors: Walter S.D. , Turner R.M. , Macaskill P. , McCaffery K.J. , Irwig L.
Published: February 2012

Outcomes in clinical trials may be affected by the choice of treatment that participants might make, if they were indeed allowed to choose (a so‐called selection effect), and by whether they actually receive their preferred treatment (a preference effect). Selection and preference effects can be important, but they cannot be estimated in the conventional trial design. An alternative approach is the two‐stage randomised trial, in which participants are first randomly divided into two subgroups. In one subgroup, participants are randomly assigned to treatments, while in the other, participants are allowed to choose their own treatment. This approach yields estimates of the direct treatment effect, and of the preference and selection effects. The latter two provide insight that goes considerably beyond what is possible in the standard randomised trial. In this paper, we determine the optimal proportion of participants who should be allocated to the choice subgroup. The precision of the estimated selection, preference and treatment effects are functions of: the total sample size; the proportion of participants allocated to choose their treatment; the variances of the outcome; the proportions of participants who select each treatment in the choice group; and the selection, preference and treatment effects themselves. We develop general expressions for the optimum proportion of participants in the choice group, depending on which effects are of primary interest. We illustrate the results with trial data comparing alternative clinical management strategies for women with abnormal results on cervical screening. Copyright © 2012 John Wiley & Sons, Ltd.
Analysis of an incomplete binary outcome derived from frequently recorded longitudinal continuous data: application to daily pain evaluation
Authors: Bunouf P. , Grouin J‐M. , Molenberghs G.
Published: February 2012

Randomized clinical trials increasingly collect daily data, frequently using electronic diaries. Such data are usually summarized into an ‘intermediate’ continuous outcome (such as the mean of the daily values in a period before a scheduled clinic visit). These are in turn often summarized further into a binary outcome, for example, indicating whether the intermediate continuous outcome has improved by a prespecified amount from randomization. This article compares and contrasts statistical approaches for analyzing such binary outcomes when the underlying study is subject to dropout so that some of the underlying diary data are missing. Such analysis involves rigorous rules for the derivation of outcomes, a thorough data exploration for the selection of covariates, and an elucidation of the missingness mechanism. The investigated statistical methods for treatment‐effect analysis are based on direct modeling and on multiple imputation and are applied either to the binary outcome or the intermediate continuous outcome or to the daily diary data. These are compared on the basis of criteria for inferences at prespecified times during the follow‐up. We show that multiple‐imputation methods are particularly well adapted to our context and that missing data imputation on the daily diary data, rather than the derived outcomes, makes best use of the available information. The data set, which motivated our investigation, comes from a placebo‐controlled clinical trial to assess the effect on pain of a new compound. Copyright © 2012 John Wiley & Sons, Ltd.
Model misspecification and robustness in causal inference: comparing matching with doubly robust estimation
Authors: Waernbaum Ingeborg
Published: February 2012

In this paper, we compare the robustness properties of a matching estimator with a doubly robust estimator. We describe the robustness properties of matching and subclassification estimators by showing how misspecification of the propensity score model can result in the consistent estimation of an average causal effect. The propensity scores are covariate scores, which are a class of functions that removes bias due to all observed covariates. When matching on a parametric model (e.g., a propensity or a prognostic score), the matching estimator is robust to model misspecifications if the misspecified model belongs to the class of covariate scores. The implication is that there are multiple possibilities for the matching estimator in contrast to the doubly robust estimator in which the researcher has two chances to make reliable inference. In simulations, we compare the finite sample properties of the matching estimator with a simple inverse probability weighting estimator and a doubly robust estimator. For the misspecifications in our study, the mean square error of the matching estimator is smaller than the mean square error of both the simple inverse probability weighting estimator and the doubly robust estimators. Copyright © 2012 John Wiley & Sons, Ltd.
Bayesian decision theoretic two‐stage design in phase II clinical trials with survival endpoint
Authors: Zhao Lili , Taylor Jeremy M.G. , Schuetze Scott M.
Published: February 2012

In this paper, we consider two‐stage designs with failure‐time endpoints in single‐arm phase II trials. We propose designs in which stopping rules are constructed by comparing the Bayes risk of stopping at stage I with the expected Bayes risk of continuing to stage II using both the observed data in stage I and the predicted survival data in stage II. Terminal decision rules are constructed by comparing the posterior expected loss of a rejection decision versus an acceptance decision. Simple threshold loss functions are applied to time‐to‐event data modeled either parametrically or nonparametrically, and the cost parameters in the loss structure are calibrated to obtain desired type I error and power. We ran simulation studies to evaluate design properties including types I and II errors, probability of early stopping, expected sample size, and expected trial duration and compared them with the Simon two‐stage designs and a design, which is an extension of the Simon's designs with time‐to‐event endpoints. An example based on a recently conducted phase II sarcoma trial illustrates the method. Copyright © 2012 John Wiley & Sons, Ltd.
Probing the Effect of Molecular Orientation on the Intensity of Chemical Enhancement Using Graphene‐Enhanced Raman Spectroscopy
Authors: Ling Xi , Wu Juanxia , Xu Weigao , Zhang Jin
Published: February 2012

A rational approach to investigate the effect of molecular orientation on the intensity of chemical enhancement using graphene‐enhanced Raman spectroscopy (GERS) is developed. A planar molecule, copper phthalocyanine (CuPc), is used as probe molecule. Annealing allows the CuPc molecule in a Langmuir–Blodgett film to change orientation from upstanding to lying down. The UV–visible absorption spectra prove the change of the molecular orientation, as well as the variation of the interaction between the CuPc molecule and graphene. The Raman spectra of the molecule in the two different orientations are compared and analyzed. The results show that chemical enhancement is highly sensitive to the molecular orientation. The different molecular orientations induce different magnitudes of the interaction between the molecule and graphene. The stronger the interaction, the more the Raman signal is enhanced. Furthermore, the sensitivity of GERS to molecular orientation is promising to determine the orientation of the molecule on graphene. Based on this molecular orientation sensitive Raman enhancement, quantitative calculation of the magnitude of the chemical enhancement is implemented for a series of Pc derivatives. It shows that the magnitude of the chemical enhancement can be used to evaluate the degree of interaction between the molecules and graphene. Moreover, an understanding of the chemical enhancement in GERS is promoted and the effect of molecular orientation on the intensity of chemical enhancement is explained.
Cell type‐specific postsynaptic effects of neuropeptide Y in substantia gelatinosa neurons of the rat spinal cord
Authors: Melnick Igor V.
Published: February 2012

Cellular mechanisms of antinociceptive action of neuropeptide Y were investigated in substantia gelatinosa (SG) neurons in rat spinal cord slices. Somatic and synaptic effects of NPY were compared in two subpopulations of cells with different firing patterns, tonic (TFNs), and delayed firing (DFNs) neurons. For the study, TFNs were selected on morphological basis: they had appearance of central and radial but not islet cells, and are likely excitatory interneurons in dorsal horn networks. In their turn, DFNs were classified as radial and vertical cells. 0.3 μM NPY via Y1 receptors activated hyperpolarizing postsynaptic current of GIRK type in majority of TFNs (∼77%) but not DFNs (∼8%). Miniature synaptic currents in all neurons were seen as a mixture of excitatory (mEPSCs) and inhibitory (mIPSCs), the frequency of the former being ∼5 times greater. The mEPSCs were mediated by glutamate receptors of AMPA subtype, while the dominant part of mIPSCs—by glycine receptors. In all cell types, NPY moderately depressed the frequency of both mEPSCs and mIPSCs; the effects occurred via Y2 and Y1 receptors, respectively. The data suggest that behavioral NPY‐evoked antinociception is achieved via postsynaptic hyperpolarization of majority of TFNs (assumingly, excitatory interneurons) via Y1 receptors and depression of the mEPSCs via Y2 receptors. Synapse, 2012. © 2012 Wiley Periodicals, Inc.
Involvement of 5‐HT2A receptor and α2‐adrenoceptor blockade in the asenapine‐induced elevation of prefrontal cortical monoamine outflow
Authors: Frånberg Olivia , Marcus Monica M. , Svensson Torgny H.
Published: February 2012

The psychotropic drug asenapine is approved for the treatment of schizophrenia and manic or mixed episodes associated with bipolar I disorder. Asenapine exhibits higher affinity for several 5‐HT receptors and α2‐adrenoceptors than for D2 receptors. Noteworthy, blockage of both the 5‐HT2A and α2‐adrenergic receptors has been shown to enhance prefrontal dopamine release induced by D2 receptor antagonists. Previous results show that asenapine, both systemically and locally, increases dopamine, noradrenaline, and serotonin release in the medial prefrontal cortex (mPFC), and that the increased dopamine release largely depends on an intracortical action. Using reverse microdialysis in freely moving rats, we here assessed the potency of low concentrations of asenapine to cause a pharmacologically significant blockage in vivo of 5‐HT2A receptors and α2‐adrenoceptors within the mPFC, and thus its ability to affect cortical monoamine release by these receptors. Intracortical administration of 1‐(2,5‐dimethoxy‐4‐iodophenyl)‐2‐aminopropane hydrochloride (DOI), a 5‐HT2A/2C receptor agonist, increased cortical monoamine release, effects that were antagonized both by asenapine and the selective 5‐HT2A antagonist M100907. Application of clonidine, an α2‐adrenoceptor agonist, significantly reduced monoamine release in the mPFC. The selective α2‐adrenoceptor antagonist idazoxan blocked, whereas asenapine partially blocked clonidine‐induced cortical dopamine and noradrenaline decrease. The effects of asenapine and idazoxan on clonidine‐induced serotonin decrease were less pronounced. Our results propose that low concentrations of asenapine in the mPFC exhibit a pharmacologically significant 5‐HT2A and α2 receptor antagonistic activity, which may contribute to enhance prefrontal monoamine release in vivo and, secondarily, its clinical effects in schizophrenia and bipolar disorder. Synapse, 2012. © 2012 Wiley Periodicals, Inc.
Higgs production via gluon fusion in the POWHEG approach in the SM and in the MSSM
Authors: Bagnaschi E. , Degrassi G. , Slavich P. , Vicini A.
Published: February 2012

Abstract

We consider the gluon fusion production cross section of a scalar Higgs boson at NLO QCD in the SM and in the MSSM. We implement the calculation in the POWHEG approach, and match the NLO-QCD results with the PYTHIA and HERWIG QCD parton showers. We discuss a few representative scenarios in the SM and MSSM parameter spaces, with emphasis on the fermion and squark mass effects on the Higgs boson distributions.
Common Mental Disorders in Patients Undergoing Lower Limb Amputation: A Population‐based Sample
Authors: Nunes Marco Antonio , de Barros Newton , Miranda Fausto , Baptista‐Silva José Carlos
Published: February 2012

Background

Amputations result in a variety of limitations that have emotional consequences for patients. The aim of the present study was evaluate non‐psychotic disorders and their associated factors in a sample of people with lower limb amputations.

Method

A cross‐sectional study was conducted that assessed the association of sociodemographic and clinical variables in relation to psychiatric disorders evaluated through the Self Reporting Questionnaire (SRQ‐20) for patients undergoing lower limb amputation. The association between the outcome of the SRQ‐20 and the other variables was assessed with the chi‐square and Student’s t test; to explore the magnitude of association adjusted for covariates, a logistic regression model was developed.

Results

One hundred‐thirty eight (138) patients were interviewed, and a prevalence of 43% (60/138) was observed for patients with mental disorders assessed with the SRQ‐20 questionnaire. We also observed that male patients (p = 0.017) and those who were married (p = 0.035) had a lower rate of psychological problems; those who were not considered independent (p = 0.036) and those with a greater number of morbid conditions (p = 0.036) showed a higher positivity in relation to psychological morbidity (p = 0.003). Logistic regression analysis showed that only the associated chronic diseases (p = 0.0328) and lack of independence (p = 0.0197) remained significant.

Conclusions

Given the high prevalence of mental disorders related to the number of associated morbid conditions and to the situation of dependency among lower limb amputees, the psychological and social assessment of these people is recommended, in addition to encouraging their self‐care and the return to their activities.
Application of a Multidimensional Nested Logit Model to Multiple-Choice Test Items
Authors: Bolt Daniel M. , Wollack James A. , Suh Youngsuk
Published: February 2012

Nested logit models have been presented as an alternative to multinomial logistic models for multiple-choice test items (Suh and Bolt in Psychometrika 75:454–473, 2010) and possess a mathematical structure that naturally lends itself to evaluating the incremental information provided by attending to distractor selection in scoring. One potential concern in attending to distractors is the possibility that distractor selection reflects a different trait/ability than that underlying the correct response. This paper illustrates a multidimensional extension of a nested logit item response model that can be used to evaluate such distinctions and also defines a new framework for incorporating collateral information from distractor selection when differences exist. The approach is demonstrated in application to questions faced by a university testing center over whether to incorporate distractor selection into the scoring of its multiple-choice tests. Several empirical examples are presented.
Rotational Uniqueness Conditions Under Oblique Factor Correlation Metric
Authors: Peeters Carel F. W.
Published: February 2012

In an addendum to his seminal 1969 article Jöreskog stated two sets of conditions for rotational identification of the oblique factor solution under utilization of fixed zero elements in the factor loadings matrix (Jöreskog in Advances in factor analysis and structural equation models, pp. 40–43, 1979). These condition sets, formulated under factor correlation and factor covariance metrics, respectively, were claimed to be equivalent and to lead to global rotational uniqueness of the factor solution. It is shown here that the conditions for the oblique factor correlation structure need to be amended for global rotational uniqueness, and, hence, that the condition sets are not equivalent in terms of unicity of the solution.
The Free Lateral Arm Flap—A Reliable Option for Reconstruction of the Forearm and Hand
Authors: Sauerbier M. , Germann G. , Giessler G. A. , Salakdeh M. Sedigh , Döll M.
Published: February 2012

Background

This retrospective study was performed to verify the advantages and disadvantages of the free lateral arm flap for defect reconstruction of the forearm and hand.

Patients and Methods

Between 2001 and 2010, 21 patients underwent defect coverage of the forearm and hand with the free lateral arm flap. The mean patient age was 48 years (17–78). The results concerning defect origin, flap size, pedicle length, operative time, revisions of the anastomoses or other complications, donor site morbidity, and length of hospital stay were evaluated.

Results

The majority of defects were caused by infections or chronic wounds. The defects were localized at the forearm in 6 cases and at the hand in 15 cases. The flap width ranged from 3 to 8 cm, and the length was from 5 to 20 cm. All flaps survived. Only in one case, a revision of the anastomosis was necessary. Primary closure of the donor site was possible in all patients. No complications occurred during the healing procedure. The majority of the patients were satisfied with the aesthetic result at the recipient site as well as at the donor site.

Conclusion

The free lateral arm flap is a very reliable option for defect coverage at the forearm and hand for small and medium size defects. A satisfactory aesthetic appearance, an excellent tissue quality, and frequent primary donor site closure are great advantages for selecting this flap.
Hydrogenation of Cottonseed Oil with Nickel, Palladium and Platinum Catalysts
Authors: Cheng H. N. , Dowd Michael K. , Easson Michael W. , Condon Brian D.
Published: February 2012

Eleven catalysts based on Ni, Pd, and Pt from two manufacturers were used for hydrogenating cottonseed oil, with the goal of minimizing trans fatty acid (TFA) content. Despite different temperatures, catalyst levels, and reaction times being used, the data from each catalyst type fell on the same curve when the TFA level was plotted against the iodine value (IV). Under low‐pressure, high‐mixing hydrogenation conditions, the Ni, Pd, and Pt catalysts all produced < 5% TFA and < 5% stearic acid at 95 IV; however, at 70 IV, only Pt catalysts produced 9% TFA and about 17% stearic acid. Kinetic modeling provided a better understanding of the relative reaction rates involved in hydrogenation. Pt catalysts converted linoleic and oleic acids more slowly to TFA and quickly hydrogenate TFA, thereby leading to low TFA levels. In comparison to other hydrogenated oils reported in the literature, equivalent or lower TFA and stearic acid levels were observed with hydrogenated cottonseed oil under the experimental conditions used.
Determination of Furan Fatty Acids in Food Samples
Authors: Vetter Walter , Laure Sophia , Wendlinger Christine , Mattes Axel , Smith Andrew W. T. , Knight David W.
Published: February 2012

Furan fatty acids (F‐acids) are valuable bioactive compounds found at low concentrations in food. A method for the quantitative determination of saturated F‐acids in food is reported. The sample preparation is based on accelerated solvent extraction, transesterification into methyl esters and silver ion chromatography (20% AgNO3 in silica, 1% deactivated) of the resulting methyl esters. There then follows determination of the enriched F‐acid methyl (or ethyl) esters by GC/EI‐MS in the selected ion monitoring (SIM) mode. The 9‐(3‐methyl‐5‐pentylfuran‐2‐yl)‐nonanoic acid ethyl ester (9M5‐EE) was used as an internal standard for recovery checks. The limit of detection was 11 pg, and the recovery rate of the silver ion chromatography was 85% (n = 5). Further F‐acid standards were used for evaluation of individual SIM‐responses. Application of the method to various biological samples gave the following results: champignons (n = 2) contained 1.7 or 2.5 mg/100 g dry weight F‐acids, while fish oil capsules (n = 5) contained between 18 and 234 mg/100 g oil F‐acids distributed over up to seven F‐acids. The concentrations and patterns were different to fresh fish. Accordingly, fish oil supplements seem to be a minor source for F‐acids compared to (fresh) fish. Organic butter samples (n = 4) contained about twice the amount of F‐acids when compared with conventional butter (n = 5).
Diskursive Konstituierung von Kulturlandschaft am Beispiel politischer Windenergiediskurse in Deutschland
Authors: Leibenath Markus , Otto Antje
Published: February 2012

There are numerous ways to define ‘landscape’ or ‘cultural landscape’—a fact that can be irritating. We do not propose any “new” notion of landscape. By contrast we examine how ‘landscape’ and ‘cultural landscape’ acquire meaning in political discourses. The objective is to introduce an approach to analyzing the discursive constitution of cultural landscape and methods by means of which it can be implemented. We draw on the post-structural discourse theory of Ernesto Laclau and we take two empirical analyses as examples: a nation-wide survey on issues of local landscape discourses and an in-depth study on landscape concepts and argumentation schemes in political discourses about the deployment of wind energy in Germany. The landscape concepts which are reproduced in the wind energy discourses sound familiar: ‘landscape as a beautiful, valuable area’, ‘landscape as an area under human influence’ and ‘landscape as something which is perceived subjectively’. However, the hegemonic discourse in favour of wind energy constantly disrupts the conservative landscape discourse which relies on the concept of ‘landscape as a beautiful, valuable area’. Certain argumentation schemes are employed to close the discourses and to immunize them against future disruptions. Generally speaking, landscape concepts play a subordinate role in wind energy discourses. In some cases, they are articulated in an instrumental, tactical manner.
Ycf1p attenuates basal level oxidative stress response in Saccharomyces cerevisiae
Authors: Paumi Christian M. , Pickin Kerry A. , Jarrar Roaa , Herren Catherine K. , Cowley Stuart T.
Published: February 2012

Ycf1p function is regulated by casein kinase 2, Cka1p, via phosphorylation of Ser251. Cka1p‐mediated phosphorylation of Ycf1p is attenuated in response to high salt stress. Previous results from our lab suggest a role for Ycf1p in cellular resistance to salt stress. Here, we show that Ycf1p plays an important role in cellular resistance to salt stress by maintaining the cellular redox balance via glutathione recycling. Our results suggest that during acute salt stress increased Sod1p, Sod2p and Ctt1p activity is the main compensatory for the loss in Ycf1p function that results from reduced Ycf1p‐dependent recycling of cellular GSH levels.
Rational design of DNA sequence‐specific zinc fingers
Authors: Kono Hidetoshi , Imanishi Miki , Negi Shigeru , Tatsutani Kazuya , Sakaeda Yui , Hashimoto Ayaka , Nakayama Chie , Futaki Shiroh , Sugiura Yukio
Published: February 2012

We developed a rational scheme for designing DNA binding proteins. The scheme was applied for a zinc finger protein and the designed sequences were experimentally characterized with high DNA sequence specificity. Starting with the backbone of a known finger structure, we initially calculated amino acid sequences compatible with the expected structure and the secondary structures of the designed fingers were then experimentally confirmed. The DNA‐binding function was added to the designed finger by reconsidering a section of the amino acid sequence and computationally selecting amino acids to have the lowest protein–DNA interaction energy for the target DNA sequences. Among the designed proteins, one had a gap between the lowest and second lowest protein–DNA interaction energies that was sufficient to give DNA sequence‐specificity.
When promoting a charity can hurt charitable giving: A metacognitive analysis
Authors: Smith Robert W. , Schwarz Norbert
Published: February 2012

Charities need to come to mind to enter a potential donor's consideration set. However, feeling familiar with a charity and its cause can facilitate or impair giving. In most cases, perceived good memory for details of the cause fosters the impression of personal importance, which increases giving (Studies 1 and 3). But when the charity aims to increase awareness of a cause, good memory for the cause suggests that awareness is already high, which impairs giving (Studies 2 and 3). Hence, promotions for awareness‐raising charities can actually have negative consequences, confirming the predictions of a metacognitive analysis.
The conservation of an aqueous fluid in inclusions in minerals and their interstices at high pressures and temperatures during the decomposition of antigorite
Authors: Chepurov A.I. , Tomilenko A.A. , Zhimulev E.I. , Sonin V.M. , Chepurov A.A. , Kovyazin S.V. , Timina T.Yu. , Surkov N.V.
Published: February 2012

An experimental study of serpentine decomposition at high pressure (4.5 GPa) was carried out to elucidate if water can be preserved in the system in the form other than structural admixtures in minerals. This problem is of interest because it is water that plays a leading role in the melting in a subducted slab and a mantle wedge. To estimate the possible content of an aqueous fluid in deep-seated rocks, a BARS pressless split-sphere apparatus was used in complex with thermobarogeochemistry and gas chromatography. It has been established that the serpentine decomposition is accompanied by the release of water, which concentrates in inclusions in the produced minerals (olivine and orthopyroxene) and their interstices. Chromatographic analysis with a stepwise heating of samples showed that most of the released water is localized in the interstices, and the rest is conserved in fluid inclusions in the minerals. The produced solid phases conserve 0.13 to 2.43 wt.% fluids as inclusions, with water amounting to 0.1–2.06 wt.%. The content of inclusions determined by microscopic examination falls in this region. Since the mobility of the fluid conserved as inclusions in the olivine and orthopyroxene is significantly lower than that in the interstices, this fluid might be better preserved in olivine-containing rocks subsided to depth.
Crust structure and composition in the southern Siberian craton (influence zone of Baikal rifting), from magnetotelluric data
Authors: Epov M.I. , Pospeeva E.V. , Vitte L.V.
Published: February 2012

The magnetotelluric (MT) profile traverses the southeastern edge of the Siberian craton and the adjacent Paleozoic Olkhon collision zone, both being within the influence area of the Baikal rifting. The processed MT data have been integrated with data on the crust structure and composition, as well as with magnetic, gravity, and seismic patterns. Large resistivity lows are interpreted with reference to new geothermal models of rifted crust in the Baikal region. The northwestern and southeastern flanks of the profile corresponding, respectively, to the craton and the collision zone differ markedly in the crust structure and composition and in the intensity of rifting-related processes, the difference showing up in the resistivity pattern. The high-grade metamorphic and granitic crust of the craton basement in the northwestern profile flank is highly resistive but it includes a conductor (less than 50 ohm · m) below 16–20 km and a nearly vertical conductive layer in the upper crust. The crust in the southeastern part, within the collision zone, is lithologically heterogeneous and heavily faulted. High resistivities are measured mainly in the upper crust composed of collisional plutonic and metamorphic complexes. Large and deep resistivity lows over the greatest part of the section are due to Cenozoic activity and rift-related transcrustal faults that vent mantle fluids constantly recharged from deeper mantle.
GENERALISING QUASINORMAL SUBGROUPS
Authors: STONEHEWER STEWART
Published: February 2012

In Cossey and Stonehewer [‘On the rarity of quasinormal subgroups’, Rend. Semin. Mat. Univ. Padova125 (2011), 81–105] it is shown that for any odd prime p and integer n≥3, there is a finite p-group G of exponent pn containing a quasinormal subgroup H of exponent pn−1 such that the nontrivial quasinormal subgroups of G lying in H can have exponent only p, pn−1 or, when n≥4 , pn−2. Thus large sections of these groups are devoid of quasinormal subgroups. The authors ask in that paper if there is a nontrivial subgroup-theoretic property 𝔛 of finite p-groups such that (i) 𝔛 is invariant under subgroup lattice isomorphisms and (ii) every chain of 𝔛-subgroups of a finite p-group can be refined to a composition series of 𝔛-subgroups. Failing this, can such a chain always be refined to a series of 𝔛-subgroups in which the intervals between adjacent terms are restricted in some significant way? The present work embarks upon this quest.
An argument of a function in H1/2
Authors: Nakazi Takahiko , Yamamoto Takanori
Published: February 2012

Let H1/2 be the Hardy space on the open unit disc. For two non-zero functions f and g in H1/2, we study the relation between f and g when f/g ≥ 0 a.e. on ∂D. Then we generalize a theorem of Neuwirth and Newman and Helson and Sarason with a simple proof.
On numbers n dividing the nth term of a linear recurrence
Authors: González Juan José Alba , Luca Florian , Pomerance Carl , Shparlinski Igor E.
Published: February 2012

We give upper and lower bounds on the count of positive integers n ≤ x dividing the nth term of a non-degenerate linearly recurrent sequence with simple roots.
Idiosyncratic Return Volatility and the Information Quality Underlying Managerial Discretion
Authors: Chen Changling , Huang Alan Guoming , Jha Ranjini
Published: February 2012

Variation in idiosyncratic return volatility from 1978 to 2009 is attributable to discretionary accrual volatility and the correlation between premanaged earnings and discretionary accruals reflective of information quality across firms. These results are robust to controls for firm operating uncertainty, growth options, business-cycle variations, and firm age and industry effects, and they highlight the importance of managerial discretion in determining idiosyncratic volatility.
Executive dysfunction and memory impairment in schizoaffective disorder: a comparison with bipolar disorder, schizophrenia and healthy controls
Authors: Amann B. , Gomar J. J. , Ortiz-Gil J. , McKenna P. , Sans-Sansa B. , Sarró S. , Moro N. , Madre M. , Landin-Romero R. , Vieta E. , Giokolea J. M. , Salvador R. , Pomarol-Clotet E.
Published: February 2012

Background

Deficits in memory and executive performance are well-established features of bipolar disorder and schizophrenia. By contrast, data on cognitive impairment in schizoaffective disorder are scarce and the findings are conflicting.

Method

We used the Wechsler Memory Scale (WMS-III) and the Behavioural Assessment of the Dysexecutive Syndrome (BADS) to test memory and executive function in 45 schizophrenic patients, 26 schizomanic patients and 51 manic bipolar patients in comparison to 65 healthy controls. The patients were tested when acutely ill.

Results

All three patient groups performed significantly more poorly than the controls on global measures of memory and executive functioning, but there were no differences among the patient groups. There were few differences in memory and executive function subtest scores within the patient groups. There were no differences in any test scores between manic patients with and without psychotic symptoms.

Conclusions

Schizophrenic, schizomanic and manic patients show a broadly similar degree of executive and memory deficits in the acute phase of illness. Our results do not support a categorical differentiation across different psychotic categories with regard to neuropsychological deficits.
Care relationships, quality of care and migrant workers caring for older people
Authors: WALSH KIERAN , SHUTES ISABEL
Published: February 2012

Migrant care workers make a substantial contribution to older adult care in Ireland and the United Kingdom (UK). However, little is known about the relational aspects of care involving migrant care workers and older people. Given that the care relationship is closely linked to quality of care, and that the Irish and UK sectors are increasingly restricted by economic austerity measures, this lack of information is a concern for care practice and policy. Our paper explores the relationship between migrant care workers and older people in Ireland and the UK and draws on data collected in both countries, including focus groups with older people (N = 41), interviews with migrant care workers (N = 90) and data from a survey of and interviews with employers. The findings illustrate the complexity of the migrant care worker–older person relationship; the prevalence of need orientated, friendship and familial-like, reciprocal, and discriminatory interlinking themes; and the role of individual, structural and temporal factors in shaping these relationships.
Towards a dialect-neutral assessment instrument for the language skills of Afrikaans-speaking children: the role of socioeconomic status
Authors: SOUTHWOOD FRENETTE
Published: February 2012

The aims of the study were to establish whether there is a correlation between the socioeconomic background of Afrikaans-speaking children and their performance on a dialect-neutral language test, and to ascertain whether the allowance the test currently makes for parental education level is sufficient. The Afrikaans version of the DiagnosticEvaluation ofLanguageVariation(Seymour, Roeper & de Villiers, 2005a) was administered to 231 Afrikaans-speaking children age 4 ; 0 to 9 ; 11 from various socioeconomic backgrounds. A positive correlation was found between the composite language scores as well as the scores for each of the language domains (syntax, pragmatics, semantics) and the primary female caregivers' highest level of education. Children with father figures present did not outperform those without. It appears that the original manner of accommodating parental education level in interpreting the children's language scores on the test is sufficient and need not be refined for the South African context.