bluuebunny/crossref_metadata_2025_split huggingface dataset:
Online H/D exchange liquid chromatography as a support for the mass spectrometric identification of the oxidation products of melatonin
Authors: Collin Fabrice , Bonnefont‐Rousselot Dominique , Yous Saï , Marchetti Catherine , Jore Daniel , Gardès‐Albert Monique 
Published: November 2008

AbstractThe hydrogen–deuterium exchange of protonated melatonin and its in vitro oxidation end‐products have been examined by liquid chromatography coupled with ion‐trap mass spectrometry. Specific H/D scrambling of protons in the C2 and C4 positions of the indole ring during gas‐phase fragmentation process was observed for both melatonin and its oxidation products. Collision‐induced dissociation spectra showed losses of variably deuterated NH3, H2O and CH3CONH2. In addition, a similar H/D scrambling behaviour was observed for the oxidation products, obtained from the opening of the indole ring by oxidative attack. Fragmentation pathways are proposed and H/D scrambling has been employed as a fingerprint, allowing identification of N1‐acetyl‐5‐methoxykynurenin (AMK), N1‐acetyl‐N2‐formyl‐5‐methoxykynurenin (AFMK), dehydro‐AFMK and hydroxymelatonin as the oxidation products of melatonin in vitro. Copyright © 2008 John Wiley & Sons, Ltd.
A novel, simple and sensitive ligand affinity capture method for detecting molecular interactions by MALDI mass spectrometry
Authors: Jørgensen Ann Louise Worsøe , Juul‐Madsen Helle Risdahl , Stagsted Jan 
Published: November 2008

AbstractA simple and sensitive ligand affinity capture method (LAC) was developed to detect biotinylated biomolecules bound to a biotin–avidin base by matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI ToF MS). Glass slides covered with a metal film for MALDI MS applications were treated with amino‐silane and derivatized with biotin followed by binding of avidin. Washing buffers with high ionic strength increased the specificity of the subsequent binding of biotinylated biomolecules to the avidin layer. A combined thin layer‐dried droplet method using α‐cyano‐4‐hydroxycinnamic acid (CHCA) in acetone or ethyl acetate resulted in the most intense ions of biotinylated polymyxin B, whereas the matrix conditions did not influence the detection of angiotensin II. Addition of biotinylated biomolecules in the low femtomole to low picomole range resulted in sufficient ion intensity for detection by the LAC method. The LAC concept was extended by binding of biotinylated lipopolysaccharide to the biotin–avidin base followed by preferential capture and specific detection of the binding antagonist polymyxin B. Copyright © 2008 John Wiley & Sons, Ltd.
Stability and accuracy analysis of an extension of the FDTD method to incorporate magnetized ferrites
Authors: Grande Ana , Pereda José A. , González Oscar , Vegas Ángel 
Published: November 2008

AbstractThis paper studies the stability and numerical dispersion of an extension of the original finite‐difference time‐domain (FDTD) method to incorporate magnetized ferrites. This extension is based on discretizing the ferrite equations by means of central differences and averages. Both partially magnetized and saturated ferrites are considered. With the aim of studying the numerical features of the resulting FDTD algorithms, we have considered the propagation of plane‐waves along longitudinally magnetized ferrite materials. This is a simple 1D problem that enables the numerical properties of the algorithms to be studied analytically. A von Neumann stability analysis shows that the stability condition of the original FDTD method is preserved and that the algorithms do not exhibit numerical dissipation. The accuracy of the numerical results is not deteriorated with respect to those obtained in the demagnetized case. Copyright © 2008 John Wiley & Sons, Ltd.
Reducing estimation risk in optimal portfolio selection when short sales are allowed
Authors: Alexander Gordon J. , Baptista Alexandre M. , Yan Shu 
Published: November 2008

AbstractThe issue of estimation risk is of particular interest to the decision‐making processes of portfolio managers who use long–short investment strategies. Accordingly, our paper explores the question of whether a VaR constraint reduces estimation risk when short sales are allowed. We find that such a constraint notably decreases errors in estimates of the expected return, standard deviation, and VaR of optimal portfolios. Furthermore, optimal portfolios in the presence of the constraint are substantially closer to the ‘true’ efficient frontier than those in its absence. Finally, we provide VaR bounds and confidence levels for the constraint that lead to the best out‐of‐sample performance. Copyright © 2008 John Wiley & Sons, Ltd.
Allied health care in Parkinson's disease: Referral, consultation, and professional expertise
Authors: Nijkrake Maarten J. , Keus Samyra H.J. , Oostendorp Rob A.B. , Overeem Sebastiaan , Mulleners Wim , Bloem Bastiaan R. , Munneke Marten 
Published: November 2008

AbstractThere is evidence for the efficacy of allied health care in Parkinson's disease (PD). However, barriers exist that hamper implementation of evidence into daily practice. We conducted a survey to investigate: (1) to what extent PD patients currently utilize allied health care for relevant problems in the core areas of allied health care and (2) the level of PD‐specific expertise among allied health professionals. Questionnaires were sent to 260 patients and 297 allied health professionals. Referral rates were 63% for physical therapy, 9% for occupational therapy, and 14% for speech therapy. PD patients with problems that can potentially be alleviated by input from allied health professionals are often not being referred. Furthermore, most patients were treated by allied health professionals who lacked PD‐specific expertise. Current referral to and delivery of allied health care in PD are suboptimal. Evidence‐based guidelines for allied health care in PD and active implementation of these guidelines are needed. © 2008 Movement Disorder Society
Sonographic substantia nigra hypoechogenicity in polyneuropathy and restless legs syndrome
Authors: Godau Jana , Manz Almut , Wevers Anne‐Kathrin , Gaenslen Alexandra , Berg Daniela 
Published: November 2008

AbstractSubstantia nigra (SN) hypoechogenicity assessed by transcranial B‐mode sonography (TCS) is typical for idiopathic restless legs syndrome (RLS). Here, we investigated whether SN hypoechogenicity may differentiate between polyneuropathy (PNP) patients with and without RLS. Seventy‐five patients with PNP, 65 healthy controls, and 75 patients with idiopathic RLS were investigated. A total of 41.2% patients with PNP additionally suffered from RLS. A total of 44.1% patients with PNP, 10.2% of healthy controls, and 91.2% of patients with idiopathic RLS exhibited SN hypoechogenicity. SN echogenicity did not differ significantly between PNP patients with and without RLS. Thus, TCS seems not suitable for the diagnosis of RLS in patients with PNP. © 2008 Movement Disorder Society
Optimal parameters in the HSS‐like methods for saddle‐point problems
Authors: Bai Zhong‐Zhi 
Published: November 2008

AbstractFor the Hermitian and skew‐Hermitian splitting iteration method and its accelerated variant for solving the large sparse saddle‐point problems, we compute their quasi‐optimal iteration parameters and the corresponding quasi‐optimal convergence factors for the more practical but more difficult case that the (1, 1)‐block of the saddle‐point matrix is not algebraically equivalent to the identity matrix. In addition, the algebraic behaviors and the clustering properties of the eigenvalues of the preconditioned matrices with respect to these two iterations are investigated in detail, and the formulas for computing good iteration parameters are given under certain principle for optimizing the distribution of the eigenvalues. Copyright © 2008 John Wiley & Sons, Ltd.
Thermal conductive PS/graphite composites
Authors: Tu Haoming , Ye Lin 
Published: November 2008

AbstractPolystyrene (PS) was compounded with graphite that possesses high thermal conductivity and layer structures, and the PS/graphite thermal conductive nano‐composites were prepared. Thermal conductivity of PS improved remarkably in the presence of the graphite, and a much higher thermal conductivity of 1.95 W/m K can be achieved for the composite with 34 vol% of colloidal graphite. The Maxwell‐Eucken model and the Agari model were used to evaluate the thermal conductivity of the composites. For the purpose of improving the interfacial compatibility of PS/graphite, realizing the exfoliation and nano‐dispersion of graphite in the PS matrix, three intercalation methods, including rolling intercalation, solvent intercalation, and pan milling intercalation, were applied to prepare the composites, and the morphologies, thermal conductivities, and mechanical properties of the composites were investigated. It should be noted that the one prepared by pan milling intercalation not only had excellent thermal conductivity but also much higher mechanical properties, resulting from a high degree of layer exfoliation of the graphite, the formation of the chain structure agglomerates of the graphite, and the creation of more conductive paths under the strong shear stress of pan milling. Copyright © 2008 John Wiley & Sons, Ltd.
Effects of methyl methacrylate grafting and in situ silica particle formation on the morphology and mechanical properties of natural rubber composite films
Authors: Satraphan P. , Intasiri A. , Tangpasuthadol V. , Kiatkamjornwong S. 
Published: November 2008

AbstractThe effects of methyl methacrylate (MMA) grafting and in situ formation of silica particles on the morphology and mechanical properties of natural rubber latex (NRL) were investigated. MMA grafting on NRL was carried out using cumyl hydroxy peroxide/tetraethylene pentamine (CHPO/TEPA) as a redox initiator couple. The grafting efficiency of the grafted NR was determined by solvent extractions and the grafted NRL was then mixed with tetraethoxysilane (TEOS), a precursor of silica, coated by adherence to a glass surface to form a film and cured at 80°C. The resultant products were characterized by FT‐IR and transmission electron microscopy. The influence of varying the MMA monomer weight ratio on the surface morphology of the composites was investigated by scanning electron and atomic force microscopy. The PMMA (poly MMA) grafted NRL particles were obtained as a core/shell structure from which the NR particles were the core seed and PMMA was a shell layer. The silane was converted into silica particles by a sol–gel process which was induced during film drying at 80°C. The silica particles were fairly evenly distributed in the ungrafted NR matrix but were agglomerated in the grafted NR matrix. The root‐mean‐square roughness increased with an increasing weight ratio of MMA in the rubber. The in situ silica particles in the grafted NR matrix slightly increased both the modulus and the tear strength of the composite film. Copyright © 2008 John Wiley & Sons, Ltd.
Study on Crystal Structure and Thermal Decomposition Mechanism of a Novel Coordination Compound [Zn(DAT)2(H2O)4](PA)2⋅2H2O
Authors: Cui Yan , Zhang Tonglai , Zhang Jianguo , Yang Li , Zhang Jin , Hu Xiaochun 
Published: November 2008

AbstractA novel coordination compound [Zn(DAT)2(H2O)4](PA)2⋅2H2O has been synthesized using 1,5‐diaminotetrazole (DAT) as ligands. It crystallizes in the monoclinic space group C2/c, with a=1.51973(19) nm, b=0.67904(9) nm, c=3.0712(4) nm, β=90.507(2)°, V=3.1692(7) nm3, Z=4, and μ=0.888 mm−1. With the intermolecular hydrogen bonds, molecules are linked together to form a three‐dimensional net structure. Thermal decomposition mechanism of the title compound was predicted based on DSC, TG‐DTG, and FT‐IR analyses. The kinetic parameters of the first exothermic process of the title compound were studied applying the Kissinger's and Ozawa–Doyle's methods.
Peripheral zone prostate cancers: Location and intraprostatic patterns of spread at histopathology
Authors: Haffner Jérémie , Potiron Eric , Bouyé Sébastien , Puech Philippe , Leroy Xavier , Lemaitre Laurent , Villers Arnauld 
Published: November 2008

AbstractBACKGROUNDTo describe the precise location of peripheral zone (PZ) prostate cancers at various stages of development and to demonstrate their pattern of intraprostatic spread from their site of origin.METHODSPZ cancers defined as cancers located in peripheral zone (PZ) including the anterolateral part of PZ, were identified from radical prostatectomy specimens. PZ cancers morphometric histopathological study included largest surface area, volume and spatial distribution.RESULTSOut of 188 PZ cancers, 179 were <4 cm3 and 168 <2 cm3. PZ cancers were still confined to their zone of origin for volumes <2 cm3. Between 2 and 4 cm3, some cancers partially spread into the transition zone or anterior fibromuscular stroma. Sixty‐four and 90% of PZ cancers <4 cm3 were located in the lower and posterior half of the gland respectively. Ten percent were located in the anterior horn of PZ. Overall, non‐index (second) cancers were located in the ipsi and contolateral side of the index cancer (largest) in 31% and 69% of cases, respectively. Cancers <2 cm3 were confined to one lobe in 164 of 168 (98%) cases and not confined in 3 out of 11 (27%) cancers 2–4 cm3. On vertical axis, only cancers ≥2 cm3 involved both apex and base.CONCLUSIONSPZ cancers contours and locations are predictable and conform to histological zone boundaries if <2 cm3 in volume. Knowledge of PZ cancers origin and pattern of spread in PZ are of importance for imaging diagnosis, guidance for biopsy and focal therapy. Prostate 69:276–282, 2009. © 2008 Wiley‐Liss, Inc.
Isotopologue fractionation during N2O production by fungal denitrification
Authors: Sutka Robin L. , Adams Gerard C. , Ostrom Nathaniel E. , Ostrom Peggy H. 
Published: November 2008

AbstractIdentifying the importance of fungi to nitrous oxide (N2O) production requires a non‐intrusive method for differentiating between fungal and bacterial N2O production such as natural abundance stable isotopes. We compare the isotopologue composition of N2O produced during nitrite reduction by the fungal denitrifiers Fusarium oxysporum and Cylindrocarpon tonkinense with published data for N2O production during bacterial nitrification and denitrification. The fractionation factors for bulk nitrogen isotope values for fungal denitrification were in the range −74.7 to −6.6‰. There was an inverse relationship between the absolute value of the fractionation factors and the reaction rate constant. We interpret this in terms of variation in the relative importance of the rate constants for diffusion and enzymatic reduction in controlling the net isotope effect for N2O production during fungal denitrification. Over the course of nitrite reduction, the δ18O values for N2O remained constant and did not exhibit a relationship with the concentration characteristic of an isotope effect. This probably reflects isotopic exchange with water. Similar to the δ18O data, the site preference (SP; the difference in δ15N between the central and outer N atoms in N2O) was unrelated to concentration during nitrite reduction and, therefore, has the potential to act as a conservative tracer of production from fungal denitrification. The SP values of N2O produced by F. oxysporum and C. tonkinense were 37.1 ± 2.5‰ and 36.9 ± 2.8‰, respectively. These SP values are similar to those obtained in pure culture studies of bacterial nitrification but quite distinct from SP values for bacterial denitrification. The large magnitude of the bulk nitrogen isotope fractionation and the δ18O values associated with fungal denitrification are distinct from bacterial production pathways; thus multiple isotopologue data holds much promise for resolving bacterial and fungal production. Our work further provides insight into the role that fungal and bacterial nitric oxide reductases have in determining site preference during N2O production. Copyright © 2008 John Wiley & Sons, Ltd.
Correction of mass spectrometric isotope ratio measurements for isobaric isotopologues of O2, CO, CO2, N2O and SO2
Authors: Kaiser Jan , Röckmann Thomas 
Published: November 2008

AbstractGas isotope ratio mass spectrometers usually measure ion current ratios of molecules, not atoms. Often several isotopologues contribute to an ion current at a particular mass‐to‐charge ratio (m/z). Therefore, corrections have to be applied to derive the desired isotope ratios. These corrections are usually formulated in terms of isotope ratios (R), but this does not reflect the practice of measuring the ion current ratios of the sample relative to those of a reference material. Correspondingly, the relative ion current ratio differences (expressed as δ values) are first converted into isotopologue ratios, then into isotope ratios and finally back into elemental δ values. Here, we present a reformulation of this data reduction procedure entirely in terms of δ values and the ‘absolute’ isotope ratios of the reference material. This also shows that not the absolute isotope ratios of the reference material themselves, but only product and ratio combinations of them, are required for the data reduction. These combinations can be and, for carbon and oxygen have been, measured by conventional isotope ratio mass spectrometers. The frequently implied use of absolute isotope ratios measured by specially calibrated instruments is actually unnecessary. Following related work on CO2, we here derive data reduction equations for the species O2, CO, N2O and SO2. We also suggest experiments to measure the required absolute ratio combinations for N2O, SO2 and O2. As a prelude, we summarise historic and recent measurements of absolute isotope ratios in international isotope reference materials. Copyright © 2008 John Wiley & Sons, Ltd.
Monitoring the Tanford transition in β‐lactoglobulin by 8‐anilino‐1‐naphthalene sulfonate and mass spectrometry
Authors: Santambrogio Carlo , Grandori Rita 
Published: November 2008

AbstractThe fluorescent dye 8‐anilino‐1‐naphthalene sulfonate (ANS) is known to interact with proteins by conformation‐specific hydrophobic interactions and rather nonspecific electrostatic interactions. To which category the complexes detectable by mass spectrometry (MS) belong is still the subject of debate. Here, the Tanford transition in β‐lactoglobulin (BLG) is exploited as an experimental device to expose hydrophobic binding sites by an increase in pH, rather than, as usually done, by lowering the pH. Complex formation is monitored by electrospray ionization (ESI)‐MS and fluorescence spectroscopy. Both techniques reveal stronger ANS binding to BLG at pH 7.9 than at pH 5.9, suggesting that dye binding inside the calyx, which is known to be hydrophobically driven in solution, can contribute to the complexes detected by ESI‐MS. Electrostatic interactions between the protein and the ANS sulfonate group can only be weaker at pH 7.9 than at pH 5.9, supporting the interpretation of the results by the protein conformational change. Lysozyme is used as a negative control, which shows no variation in the interaction with ANS in the same range of pH, in the absence of conformational changes. However, comparison of MS and fluorescence data at variable pH for BLG and myoglobin (Mb) suggests that conformation‐specific ANS binding to proteins is detectable by ESI‐MS only inside well‐structured cavities of folded structures, like the BLG calyx and apoMb heme pocket. Indeed, ANS interactions with highly dynamic structures or molten globules, although detectable in solution, are easily lost in the gas phase. Copyright © 2008 John Wiley & Sons, Ltd.
Motion planning in urban environments
Authors: Ferguson Dave , Howard Thomas M. , Likhachev Maxim 
Published: November 2008

AbstractWe present the motion planning framework for an autonomous vehicle navigating through urban environments. Such environments present a number of motion planning challenges, including ultrareliability, high‐speed operation, complex intervehicle interaction, parking in large unstructured lots, and constrained maneuvers. Our approach combines a model‐predictive trajectory generation algorithm for computing dynamically feasible actions with two higher level planners for generating long‐range plans in both on‐road and unstructured areas of the environment. In the first part of this article, we describe the underlying trajectory generator and the on‐road planning component of this system. We then describe the unstructured planning component of this system used for navigating through parking lots and recovering from anomalous on‐road scenarios. Throughout, we provide examples and results from “Boss” an autonomous sport utility vehicle that has driven itself over 3,000 km and competed in, and won, the DARPA Urban Challenge. © 2008 Wiley Periodicals, Inc.
A re‐evaluation of the ‘quantile approximation method’ for random effects meta‐analysis
Authors: Jackson Dan , Bowden Jack 
Published: November 2008

AbstractThe quantile approximation method has recently been proposed as a simple method for deriving confidence intervals for the treatment effect in a random effects meta‐analysis. Although easily implemented, the quantiles used to construct intervals are derived from a single simulation study. Here it is shown that altering the study parameters, and in particular introducing changes to the distribution of the within‐study variances, can have a dramatic impact on the resulting quantiles. This is further illustrated analytically by examining the scenario where all trials are assumed to be the same size. A more cautious approach is therefore suggested, where the conventional standard normal quantile is used in the primary analysis, but where the use of alternative quantiles is also considered in a sensitivity analysis. Copyright © 2008 John Wiley & Sons, Ltd.
Vitellogenin induction by a mixture of steroidal estrogens in freshwater fishes and relevant risk assessment
Authors: Zhang Hui , Kong Fan‐Xiang , Wang Shi‐He , Yu Yang , Zhang Min 
Published: November 2008

AbstractThe study method on combined effects of environmental contaminant mixture and ecological risk assessment was discussed. Batch tests were conducted to assess the in vivo potency of binary mixtures of estrogens using plasma vitellogenin concentrations in male crucian carp as the endpoint. The estrogenic potencies of 17β‐estradiol (E2) and 17α‐ethynylestradiol (EE2) were determined following 14 day exposure to the individual chemicals and equipotent binary mixtures. A Nonlinear regression was obtained and 95% confidence limits of effect concentration were achieved using the bootstrap method. Concentration‐response curve for fixed ratio binary mixtures of E2 and EE2 was compared with those for individual chemicals, using the biomathematical models of concentration addition (CA) and independent action (IA). A complete overlap was found for the CA predictions with the 95% confidence interval of the best‐fit regression line of the observed responses, and the IA predictions was shown lower than the observations. The observed mixture effects were considerably higher than those of the hormone alone and far exceeded the 95% confidence interval of the estrogen regression lines. The predicted effects of binary mixtures at different mixture ratios indicated that the potential impact of components on mixture would depend predominantly on its concentration, the mixture ratio and its relative potency. Results suggested that E2 and EE2 acted together in an additive manner and the combined effects can be accurately predicted in whole range of exposure concentration by the models of CA and IA, the model of CA might be realistic, but more useful for ecological risk assessment. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009.