bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production and isolation of ligated metal(IV)‐oxo ions by tandem mass spectrometry
Authors: Taylor Ivan F. , Blanksby Stephen J. , Colbran Stephen B. , Willett Gary D. 
Published: March 2010

AbstractHigh valent metal(IV)‐oxo species, [M(O)(MeIm)n(OAc)]+ (M = Mn–Ni, MeIm = 1‐methylimidazole, n = 1–2), which are relevant to biology and oxidative catalysis, were produced and isolated in gas‐phase reactions of the metal(II) precursor ions [M(MeIm)n(OAc)]+ (M = Mn–Zn, n = 1–3) with ozone. The precursor ions [M(MeIm)(OAc)]+ and [M(MeIm)2(OAc)]+ were generated via collision‐induced dissociation of the corresponding [M(MeIm)3(OAc)]+ ion. The dependence of ozone reactivity on metal and coordination number is discussed. Copyright © 2010 John Wiley & Sons, Ltd.
Surface‐activated chemical ionization time‐of‐flight mass spectrometry and labeling‐free approach: two powerful tools for the analysis of complex plant functional proteome profiles
Authors: Finiguerra Alessandro , Spadafora Antonia , Filadoro Dina , Mazzuca Silvia 
Published: March 2010

AbstractSurface‐activated chemical ionization (SACI) has been widely used in recent years to analyze a range of different compounds (e.g., peptides, street drugs, amino acids). The main benefits of this technology are its high sensitivity and its effectiveness under different chromatographic conditions. Here, we used SACI in conjunction with a highly selective quadrupole time‐of‐flight mass analyzer to characterize a complex proteome pattern after separation by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE). The data obtained were compared with those obtained using the micro‐electrospray ionization (ESI) approach, which showed that using SACI strongly increased the number of detectable proteins. The higher sensitivity is mainly due to the ability of SACI to selectively produce singly charged species of high intensity under full‐scan conditions and doubly charged species for tandem mass spectrometric (MS/MS) peptide characterization by simply changing the ionization conditions during data acquisition. Copyright © 2010 John Wiley & Sons, Ltd.
Stable ion complexes of vitamin A species (retinol) in solution as detected by mass spectrometry
Authors: Sánchez‐Guijo Alberto , Montero Olimpio 
Published: March 2010

AbstractMechanisms of retinol (ROL) transport in plasma alternative to that involving the Retinol‐Binding Protein (RBP) have been hypothesized after RBP‐knockout mice were shown to be viable and fertile. Accordingly, the possibility of a ROL fraction circulating free in plasma has been suggested. In this study, stable complex formation between ROL and the physiological relevant ions Na+, Li+, and K+ was investigated by using mass spectrometry and assessed in regard to the aforementioned alternative mechanism. The ROL‐Na complex was found to be kinetically favoured with respect to the ROL‐Li and ROL‐K complexes. Fragmentation of the [ROL‐Na]+ adduct rendered the carbocation [ROL+H–H2O]+ (m/z 269) and NaOH as neutral loss. In consonance with these results, it is hypothesized on the possibility of the complex [ROL‐Na]+ being an alternative way of ROL transport to cells, as well as an intermediate in cis/trans isomerism. Copyright © 2010 John Wiley & Sons, Ltd.
Direct quantification of 11‐nor‐Δ9‐tetrahydrocannabinol‐9‐carboxylic acid in urine by liquid chromatography/tandem mass spectrometry in relation to doping control analysis
Authors: Chebbah C. , Pozo O. J. , Deventer K. , Van Eenoo P. , Delbeke F. T. 
Published: March 2010

AbstractAn accurate and precise method for the quantification of 11‐nor‐Δ9‐tetrahydrocannabinol‐9‐carboxylic acid (THCA) in urine by liquid chromatography/tandem mass spectrometry (LC/MS/MS) for doping analysis purposes has been developed. The method involves the use of only 200 µL of urine and the use of D9‐THCA as internal standard. No extraction procedure is used. The urine samples are hydrolysed using sodium hydroxide and diluted with a mixture of methanol/glacial acetic acid (1:1). Chromatographic separation is achieved using a C8 column with gradient elution. All MS and MS/MS parameters were optimised in both positive and negative electrospray ionisation modes. For the identification and the quantification of THCA three product ions are monitored in both ionisation modes. The method is linear over the studied range (5–40 ng/mL), with satisfactory intra‐and inter‐assay precision, and the relative standard deviations (RSDs) are lower than 15%. Good accuracy is achieved with bias less than 10% at all levels tested. No significant matrix effects are observed. The selectivity and specificity are satisfactory, and no interferences are detected. The LC/MS/MS method was applied for the analysis of 48 real urine samples previously analysed with a routine gas chromatography/mass spectrometry (GC/MS) method. A good correlation between the two methods was obtained (r2 > 0.98) with a slope close to 1. Copyright © 2010 John Wiley & Sons, Ltd.
Gas‐fragmentation study of the novel synthetic zwitterionic drug 3‐methyl‐9‐(2‐oxa‐2λ5‐2H‐1,3,2‐oxazaphosphorine‐2‐cyclohexyl)‐3,6,9‐triazaspiro[5,5]undecane chloride (SLXM‐2) by electrospray ionization tandem mass spectrometry
Authors: Wang Siting , Song Yan , Wang Jiao , Ling Xiaomei , Ge Zemei , Li Runtao , Cui Jingrong 
Published: March 2010

AbstractThe zwitterionic drug 3‐methyl‐9‐(2‐oxa‐2λ5‐2H‐1,3,2‐oxazaphosphorine‐2‐cyclohexyl)‐3,6,9‐triazaspiro[5,5]undecane chloride (SLXM‐2) is a novel synthetic compound which has shown anticancer activity and low toxicity in vivo. In this study, the various gas‐phase fragmentation routes were analyzed by electrospray ionization mass spectrometry (positive ion mode) in conjunction with tandem mass spectrometry (ESI‐MSn) for the first time. In ESI‐MS the fragment ion at m/z 289 (base peak) was formed by loss of the chlorine anion from the zwitterionic precursor SLXM‐2. The fragment ion at m/z 232 was formed from the ion at m/z 289 by loss of 1‐methylaziridine. The detailed gas‐phase collision‐induced dissociation (CID) fragmentation mechanisms obtained from the various precursor ions extracted from the zwitterionic SLXM‐2 drug was obtained by tandem mass spectrometry analyses. Copyright © 2010 John Wiley & Sons, Ltd.
Characterization of complex assemblages of organic acids in geological samples by negative electrospray ionization mass spectrometry using a double‐focusing magnetic sector field mass spectrometer
Authors: Pötz Stefanie , Wilkes Heinz , Witt Matthias , Horsfield Brian 
Published: March 2010

AbstractFour different geological sample types (a crude oil, a crude oil asphaltene, a reservoir core extract and a reservoir core asphaltene) have been characterized by negative ionization electrospray mass spectrometry at low and high mass resolution using a double‐focusing magnetic sector field mass spectrometer. The mass range, shape of the spectra and the signal distribution of the acidic constituents as well as the average molecular weights, the total ion abundance and signal intensity in the spectra were compared for the different sample types. Nominal mass classes have been evaluated and Kendrick mass plots were generated in order to identify homologous series. For the crude oil sample, accurate mass assignments were made by high‐resolution double‐focusing magnetic sector field mass spectrometry (DFMSFMS) and were compared with those obtained by negative ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). With both instrument types, compounds with the molecular composition CnH2n+zO2, among which carboxylic acids predominated, were the main acidic compound class detectable in negative ESI mass spectra. Good agreement was achieved for the double bond class distribution and the carbon number distribution of the O2 class. In addition, minor compound classes could be identified using FTICRMS. Copyright © 2010 John Wiley & Sons, Ltd.
Exploring rearrangements along the fragmentation of glutaric acid negative ion: a combined experimental and theoretical study
Authors: Kanawati Basem , Schmitt‐Kopplin Philippe 
Published: March 2010

AbstractGlutaric acid, a common short‐chain aliphatic dicarboxylic acid, was investigated in the negative ion mode by subjecting its [M–H]− ion to collision‐induced dissociation (CID) experiments in an infinity ion cyclotron resonance (ICR) cell coupled to a hexapole–quadrupole–hexapole ion guide. A 12 Tesla magnet was used for high‐resolution measurements. Two distinctive main pathways were observed in the MS/MS spectrum. The fragmentation pathways were also thoroughly investigated in a density functional theory (DFT) study involving a B3LYP/6‐311+G(2d,p)//B3LYP/6‐311+G(d,p) level of theory. Elimination of CO2 from the [M–H]− ion of the dicarboxylic acid takes place in a concerted mechanism, by which a 1,5 proton shift occurs from the intact carboxyl group to the methylene moiety located in the α position relative to the deprotonated carboxyl group. This concerted mechanism stabilizes the terminal negative charge and deprotonates the second carboxylic acid group. Water elimination from the [M–H]− ion does not take place by means of a simple proton removal from the α methylene group – and OH− release from the carboxylate group to abstract an additional α proton thus leading to the formation of a deprotonated ketene anion. In the case of this dicarboxylic acid, a new mechanism was found for water elimination, which differs from that known for aliphatic monocarboxylic acids. An intramolecular interaction between the deprotonated and the intact carboxyl groups plays a key role in making a new energetically favourable mechanism. The DFT study also reveals that a combined loss of CO2 and H2O in the form of H2CO3 is possible. Copyright © 2010 John Wiley & Sons, Ltd.
The performance implications of intra‐ and inter‐regional geographic diversification
Authors: Qian Gongming , Khoury Theodore A. , Peng Mike W. , Qian Zhengming 
Published: March 2010

AbstractEngaging the debate regarding the appropriate level of geographic diversification for multinational enterprises (MNEs), we examine a critical, yet unresolved, question: How is performance impacted by the MNE's level of intra‐ and inter‐regional diversification versus the total level of geographic diversification? Using data from 123 U.S.‐based MNEs over a seven‐year period and leveraging both sales‐based and subsidiary‐based measures for diversification, we find that performance increases at an increasingly higher rate as firms concentrate more heavily on intra‐regional diversification. Regarding inter‐regional diversification and total geographic diversification, we find inverted‐U relationships to exist between firm performance and the level of geographic diversification. Different from recent research on multinationality, our robustness checks indicate no evidence of a sigmoidal relationship between the degree of regional diversification and performance. Copyright © 2010 John Wiley & Sons, Ltd.
FDI spillovers in an emerging market: the role of foreign firms' country origin diversity and domestic firms' absorptive capacity
Authors: Zhang Yan , Li Haiyang , Li Yu , Zhou Li‐An 
Published: March 2010

AbstractPrior literature on foreign direct investment (FDI) spillovers has mainly focused on how the presence of FDI affects the productivity of domestic firms. In this study, we advance the literature by examining the effect of the diversity of FDI country origins on the productivity of domestic firms. We propose that the diversity of FDI country origins can facilitate FDI spillovers by increasing the variety of technologies and management practices brought by foreign firms, to which domestic firms are exposed and that they can potentially utilize. Further, the extent to which domestic firms can utilize these technologies and practices depends upon their absorptive capacity. Using panel data on Chinese manufacturing firms during the period 1998–2003, our results support these propositions. We find that the diversity of FDI country origins in an industry has a positive relationship with the productivity of domestic firms in the industry. This positive relationship is stronger when domestic firms are larger, and when the technology gap between FDI and the domestic firms is intermediate. Copyright © 2010 John Wiley & Sons, Ltd.
One step further towards the dematerialization of building envelopes — the new European Investment Bank building in Luxembourg
Authors: Sobek Werner , Tarazi Frank 
Published: March 2010

AbstractThe new office building for the European Investment Bank in Luxembourg was built to a design by Dusseldorf‐based architect Christoph Ingenhoven. The particular features of this building are its cable façades as well as the curving glass envelope spanning over the whole structure. This article provides a detailed description of the steel‐and‐glass structures to the façades and barrel vault, which are the main elements determining the building’s appearance. Particular attention is paid to the very high safety standards applied to all structures. Thanks to a sophisticated combination of various loadbearing elements it was possible to unite maximum transparency with remarkable robustness.
The “general method” for assessing the out‐of‐plane stability of structural members and frames and the comparison with alternative rules in EN 1993 — Eurocode 3 — Part 1‐1
Authors: Bijlaard Frans , Feldmann Markus , Naumes Johannes , Sedlacek Gerhard 
Published: March 2010

AbstractThe key to harmonizing the rules for the assessment of in‐plane and out‐of‐plane stability of structural steel members is a common definition of equivalent geometric imperfections. The nature of these is given by the elastic‐critical buckling mode and their amplitudes are obtained from the evaluation of test results for member resistance according to EN 1990 — Annex D — Basis of structural design.EN 1993 — Part 1‐1 — Design of steel structures — contains a set of alternative rules for stability checks. Of these, the “general method” could potentially function as a consistent and reliable set of rules for assessing both flexural and lateral‐torsional buckling for any loading and support conditions, and also cover the case of combined compression, biaxial bending and torsion. This report describes the basis of the “general method” and its extension to the treatment of any stability problems in bar structures.The reliability of the method is verified by test evaluations. This means it can be used as reference method for checking the accuracy of the other alternative stability rules in EN 1993‐1‐1. A comparison shows that the other alternative rules meet the requirements on the whole, with deviations of about ±10 %, which define their modelling uncertainty.
Non‐linear seismic dynamic response of curved steel bridges equipped with LRB supports
Authors: Galindo Carlos Mendez , Belda Javier Gil , Hayashikawa Toshiro 
Published: March 2010

AbstractThe susceptibility of horizontally curved steel highway bridges to seismic damage increases substantially when subjected to Level II Earthquake Ground Motions. The growing need for safer bridges has stimulated the replacement of vulnerable steel bearing supports with seismic isolation devices. The purpose of the present study is to analyse the overall performance of highway bridges, with an emphasis on the effectiveness of seismic isolation based on Lead Rubber Bearings (LRB). The analysis of the bridges was performed on three‐dimensional models using a numerical method based on the dynamic response analysis, considering both geometric and material non‐linearities. The non‐linear bridge models were subjected to strong ground motion records from the 1995 Kobe earthquake. The efficiency of using LRB supports on curved highway viaducts is demonstrated in this study. The results show that seismic isolation improves the seismic response of curved bridges and reduces excessive seismic damage.
Stresses in the zone of process openings in the shell of a vertical cylindrical steel tank
Authors: Ziólko Jerzy , Supernak Ewa , Mikulski Tomasz 
Published: March 2010

AbstractDiverse process openings have to be provided in the bottom parts of cylindrical tanks for the storage of liquids. Pipelines have to be connected to each tank product. These are mostly 700 mm in diameter in the case of tanks with a capacity of 50 000 m3 and more. An opening in the tank shell for a pipeline of such a diameter weakens the shell significantly. Furthermore, this occurs in the region where the material is exposed to the greatest stresses — in the zone of boundary disturbances at the junction between the cylindrical shell and the bottom plate.In the shells of tanks for the storage of crude oil, a large opening in the form of a rectangle, joined at the top to a half‐ellipse, have to be formed in the same zone of boundary disturbances, directly at the shell/bottom junction. Very often such openings are more than 900 mm high, and they can be up to 1500 mm wide (depending on tank capacity). The opening is required for a so‐called cleanout door, designed for the removal of deposits precipitating from crude oil and lying on the tank bottom. To be effective during the cleaning of a tank, such clean‐out doors should have their lower edge flush with the tank bottom. That causes a large change of stresses in the zone of boundary disturbances both in the shell and in the tank bottom. For that reason, both of these structural components have to be significantly strengthened in the proximity of the clean‐out door.This paper is concerned with the analysis of stresses in the region of strengthening at both the aforementioned openings in the tank shell. Since the nature of stress changes — and therefore also the strengthening around these openings — is different, this paper has been divided into two parts, each of them having a separate introduction and presenting separate conclusions. Those conclusions are fit for practical applications.
Endoplasmic reticulum stress responses differ in meninges and associated vasculature, striatum, and parietal cortex after a neurotoxic amphetamine exposure
Authors: Thomas Monzy , George Nysia I. , Saini Upasana T. , Patterson Tucker A. , Hanig Joseph P. , Bowyer John F. 
Published: March 2010

AbstractAmphetamine (AMPH) is used to treat attention deficit and hyperactivity disorders, but it can produce neurotoxicity and adverse vascular effects at high doses. The endoplasmic reticulum (ER) stress response (ERSR) entails the unfolded protein response, which helps to avoid or minimize ER dysfunction. ERSR is often associated with toxicities resulting from the accumulation of unfolded or misfolded proteins and has been associated with methamphetamine toxicity in the striatum. The present study evaluates the effect of AMPH on several ERSR elements in meninges and associated vasculature (MAV), parietal cortex, and striatum. Adult, male Sprague–Dawley rats were exposed to saline, environmentally induced hyperthermia (EIH) or four consecutive doses of AMPH that produce hyperthermia. Expression changes (mRNA and protein levels) of key ERSR‐related genes in MAV, striatum, and parietal cortex at 3 h or 1 day postdosing were monitored. AMPH increased the expression of some ERSR‐related genes in all tissues. Atf4 (activating transcription factor 4, an indicator of Perk pathway activation), Hspa5/Grp78 (Glucose regulated protein 78, master regulator of ERSR), Pdia4 (protein disulfide isomerase, protein‐folding enzyme), and Nfkb1 (nuclear factor of kappa b, ERSR sensor) mRNA increased significantly in MAV and parietal cortex 3 h after AMPH. In striatum, Atf4 and Hspa5/Grp78 mRNA significantly increased 3 h after AMPH, but Pdia4 and Nfkb11 did not. Thus, AMPH caused a robust activation of the Perk pathway in all tissues, but significant Ire1 pathway activation occurred only after AMPH treatment in the parietal cortex and striatum. Ddit3/Chop, a downstream effector of the ERSR pathway related to the neurotoxicity, was only increased in striatum and parietal cortex. Conversely, Pdia4, an enzyme protective in the ERSR, was only increased in MAV. The overall ERSR manifestation varied significantly between MAV, striatum, and parietal cortex after a neurotoxic exposure to AMPH. Synapse 2010. Published 2010 Wiley‐Liss, Inc.
Cocaine enhancement of long‐term potentiation in the CA1 region of rat hippocampus: Lamina‐specific mechanisms of action
Authors: Stramiello Michael , Wagner John J. 
Published: March 2010

AbstractThere is an expanding body of work characterizing dopaminergic modulation of synaptic plasticity in the hippocampus CA1 region, an area known to be involved in learning and memory. However, in vitro studies to date have focused almost exclusively on the proximal and distal apical dendritic layers (strata radiatum and lacunosum moleculare, respectively). In this report, we establish that dopaminergic activity can enhance long‐term potentiation (LTP) in the basal dendritic layer (stratum oriens) of CA1 in the rat hippocampal slice preparation. Application of the D1/5 agonist SKF38393 (20 μM) significantly increased the magnitude of basal LTP of the fEPSP response following high‐frequency stimulation of the Schaffer collateral/commissural inputs in the stratum oriens layer. In addition, endogenous dopamine (DA) activity facilitated by the presence of cocaine (6 μM) was also capable of enhancing the magnitude of basal LTP. Prior application of the D1/5 antagonist SKF83566 (2 μM) prevented this effect of cocaine, indicating that endogenously released dopamine was exerting its LTP‐enhancing effect in stratum oriens via activation of D1/5 receptors. This final result stands in contrast with the previously characterized effects of cocaine on apical LTP in the stratum radiatum, which instead have been shown to require D3 receptor activation. These observations demonstrate that dopaminergic mechanisms resulting in the enhancement of hippocampal LTP are lamina specific at Schaffer collateral/commissural synapses in the CA1 region. Synapse 2010. © 2010 Wiley‐Liss, Inc.
Changes in dendritic morphology and spine density in motor cortex of the adult rat after stroke during infancy
Authors: Hartle Kelly D. , Jeffers Matthew S. , Ivanco Tammy L. 
Published: March 2010

AbstractCognitive and motor deficits are pervasive in children that suffer early brain injury. The aim of this study was to determine the impact that early damage has on dendritic spine density and other aspects of dendritic morphology of neurons in the motor cortex. Also of interest was how changes in dendritic structure evolved across the lifespan. Ischemia was induced in 10‐day‐old Long Evans rats by injection of Rose Bengal dye and a laser positioned over right motor cortex. Animals were sacrificed at two and six months of age, and brains were processed for Golgi‐Cox staining. Animals exposed to early damage exhibited increases in length of basilar dendrites at two months of age, however no differences in spine density were found across groups at this age. At six months of age, injured animals demonstrated an overall decrease in apical and basilar spine density. Our results suggest that the changes in dendritic length and spine density observed after early damage are unable to be maintained as the animal ages. The observation that increases in spine density do not necessarily coincide with increases in dendritic length suggests that the two processes may not be dependent on one another and suggest two independent plasticity processes responding to damage. Synapse 2010. © 2010 Wiley‐Liss, Inc.