bluuebunny/crossref_metadata_2025 huggingface dataset:
Large lytic cranial lesions: A differential diagnosis from pre‐Angkorian Cambodia
Authors: Domett K.M. , Buckley H.R.
Published: December 2010

A late pre‐Angkorian period, c. 350 BC ‐ 200 AD, cemetery has been excavated in the village of Phum Snay, in northwestern Cambodia. In addition to the cemetery sample, a large sample of stratigraphically unprovenanced human skeletal material was uncovered in the village through extensive looting over the last 5–10 years. Both sample sets were available for study but the latter is comprised of only isolated bone elements. The differential diagnosis of the cause of lesions in one isolated cranial vault from this sample is presented here. Widespread, primarily lytic, lesions are concentrated on the frontal and anterior parietal bones, with an additional large lesion on the occipital bone. Lesions vary in size ranging from approximately 5–30 mm in diameter. A detailed description of these lesions is given and a differential diagnosis is presented that includes infectious disease, such as osteomyelitis, tuberculosis and treponemal disease, and also several forms of cancer including metastatic carcinoma, meningioma and multiple myeloma, and finally Langerhans Cell Histiocytosis. The diagnosis is difficult, given the lack of material, but it is suggested that one of the forms of Langerhans Cell Histiocytosis is the most likely candidate. The presence of such large and diffuse lesions is unusual in prehistoric Southeast Asia so the significance of this is also discussed. Copyright © 2010 John Wiley & Sons, Ltd.
Microbial desulfurization of SBR ground rubber by Sphingomonas sp. and its utilization as filler in NR compounds
Authors: Jiang Guangming , Zhao Suhe , Li Wenji , Luo Jingyuan , Wang Yaqin , Zhou Quansheng , Zhang Cuiru
Published: December 2010

Microbial desulfurization of waste tyre rubber has been investigated with great efforts since 1990s, because waste rubber has created serious ecological and environmental problems. A microbial desulfurization technique for SBR ground rubber has been developed by a novel sulfur‐oxidizing bacterium Sphingomonas sp. The adaptability of Sphingomonas sp. with SBR ground rubber was tested with the amounts of SBR ground rubber varying from 0.5 to 4% g/l. The sol fraction of desulfurized SBR ground rubber increased 70%, compared with SBR ground rubber without desulfurization. Fourier transform infrared spectroscopy‐attenuated total reflectance (FTIR‐ATR) spectrum and X‐ray photoelectron spectroscopy (XPS) analysis of the desulfurized surface of vulcanized SBR flakes revealed that not only the oxidation of crosslinked SS and SC bonds, but also the rupture of CC double bonds had happened to SBR vulcanizates during microbial desulfurization. The cure characteristics, such as scorch time and optimum cure time of natural rubber (NR) vulcanizates filled, were found to decrease with increasing contents of desulfurized SBR ground rubber, due to some reactive groups on its surface. NR vulcanizates filled with desulfurized SBR ground rubber had lower crosslink density and hardness, higher tensile strength and elongation at break, compared with those filled with SBR ground rubber of the same amount. Dynamic mechanical properties indicated that there were better crosslink distribution and stronger interfacial bonding between NR matrix and desulfurized SBR ground rubber. Scanning electron microscope (SEM) photographs showed that the fracture surfaces of NR vulcanizates filled with desulfurized SBR ground rubber had more smooth morphologies. Copyright © 2010 John Wiley & Sons, Ltd.
Ceramic nanofibers fabricated by electrospinning and their applications in catalysis, environmental science, and energy technology
Authors: Dai Yunqian , Liu Wenying , Formo Eric , Sun Yueming , Xia Younan
Published: December 2010

This paper provides a brief review of current research activities that focus on the fabrication of ceramic nanofibers by electrospinning, as well as their applications in various areas. We begin with a brief introduction to electrospinning in the context of ceramic nanofibers, and the methods for preparing aligned and/or hollow nanofibers. We then discuss approaches to the fabrication of nanofibers with a hierarchical structure. We continue with a highlight of some recent applications enabled by electrospun ceramic nanofibers, with a focus on three areas: catalysis, environmental science, and energy technology, which are expected to become the most important and exciting subjects of research in this century. In the end, we conclude this review with some perspectives on the future directions and implications for this new class of functional nanomaterials. Copyright © 2010 John Wiley & Sons, Ltd.
Hydrogels for in situ encapsulation of biomimetic membrane arrays
Authors: Ibragimova Sania , Stibius Karin , Szewczykowski Piotr , Perry Mark , Bohr Henrik , Hélix‐Nielsen Claus
Published: December 2010

Hydrogels are hydrophilic, porous polymer networks that can absorb up to thousands of times their own weight in water. They have many potential applications, one of which is the encapsulation of freestanding black lipid membranes (BLMs) for novel separation technologies or biosensor applications. We investigated gels for in situ encapsulation of multiple BLMs formed across apertures in a hydrophobic ethylene tetrafluoroethylene (ETFE) support. The encapsulation gels consisted of networks of poly(ethylene glycol)‐dimethacrylate or poly(ethylene glycol)‐diacrylate polymerized using either a chemical initiator or a photoinitiator. The hydrogels were studied with regards to volumetric stability, porosity, and water permeability. All hydrogels had pore sizes around 7 nm with volumetric changes >2% upon crosslinking. Photoinitiated hydrogels had a lower hydraulic water permeability compared to chemically initiated hydrogels; however, for all hydrogels the permeability was several‐fold higher than the water permeability of conventional reverse osmosis (RO) membranes. Lifetimes of freestanding BLM arrays in gel precursor solutions were short compared to arrays formed in buffer. However, polymerizing (crosslinking) the gel stabilized the membranes and resulted in BLM arrays that remained intact for days. This is a substantial improvement over lifetimes for freestanding BLM arrays. Optical images of the membranes and single channel activity of incorporated gramicidin ion channels showed that the lipid membranes retained their integrity and functionality after encapsulation with hydrogel. Our results show that hydrogel encapsulation is a potential means to provide stability for biomimetic devices based on functional proteins reconstituted in biomimetic membrane arrays. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis and characterization of imidized poly(styrene‐maleic anhydride) nanoparticles in stable aqueous dispersion
Authors: Samyn Pieter , Deconinck Marlies , Schoukens Gustaaf , Stanssens Dirk , Vonck Leo , Van den Abbeele Henk
Published: December 2010

Organic nanoparticles are synthesized by partial imidization of high‐molecular weight styrene(maleic‐anhydride) with 26 to 34 mol% maleic anhydride, in aqueous environment and presence of ammonium hydroxide. The nanoparticle dispersions have a maximum solid content of 35 wt% and good stability that critically depends on the ratio of imidized and ammonolyzed maleic anhydride moieties. The deprotonated residual maleic anhydride moieties provide dispersion stability at pH > 4, while protonation at pH < 4 causes nanoparticle sedimentation. After presentation of the synthesis conditions, the imidization reaction is characterized by FT‐IR and Raman spectroscopy, followed by thermal analysis (TGA, DSC), and morphological characterization (DLS, SEM, TEM, AFM). The reaction conditions were optimized by physical characterization of various dispersions, and finally nanoparticles could be obtained with a maximum degree of imidization of 77% in dispersed conditions, or 90 to 95% after drying that are favorable for coating applications.
Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis and swelling characteristics of a pH‐responsive guar gum‐g‐poly(sodium acrylate)/medicinal stone superabsorbent composite
Authors: Zhai Naihua , Wang Wenbo , Wang Aiqin
Published: December 2010

A series of pH‐responsive superabsorbent composites were synthesized by the free‐radical grafting copolymerization of natural guar gum (GG), partially neutralized acrylic acid (NaA), and medicinal stone (MS) using ammonium persulfate (APS) as the initiator and N,N′‐methylene‐bis‐acrylamide (MBA) as the crosslinker. The structure, surface morphologies, and thermal stability of the developed composites were characterized by FTIR spectra, SEM, and TGA techniques, respectively. The effects of various saline, surfactant, and dye solutions on swelling properties were investigated, and the pH‐responsivity was also evaluated. Results indicated that NaA had been grafted onto GG macromolecular chains and MS participated in the polymerization reaction. The incorporation of MS obviously improved the surface structure, thermal stability, water absorption capacity, and rate. Multivalent saline, cationic surfactant, and dye showed more remarkable effect on the water absorption than did monovalent or anionic ones. The composites showed excellent responsive properties and reversible On–Off switching characteristics in various pH buffer solutions, which provided great possibility to extend the application domain of the superabsorbent composites. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers
Nonisothermal transient filling simulation of fiber suspended viscoelastic liquid in a center‐gated disk
Authors: Park Jang Min , Kwon Tai Hun
Published: December 2010

The present study numerically investigates a fiber orientation in injection‐molded short fiber reinforced thermoplastic composite by using a rheological model, which includes the nonlinear viscoelasticity of polymer and the anisotropic effect of fiber in the total stress. A nonisothermal transient‐filling process for a center‐gated disk geometry is analyzed by a finite element method using a discrete‐elastic‐viscous split stress formulation with a matrix logarithm for the viscoelastic fluid flow and a streamline upwind Petrov–Galerkin method for convection‐dominated problems. The numerical analysis result is compared to the experimental data available in the literature in terms of the fiber orientation in center‐gated disk. The effects of the fiber coupling and the slow‐orientation kinetics of the fiber are discussed. Also, the effect of the injection‐molding processing condition is discussed by varying the filling time and the mold temperature. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers
Application of NMR‐based metabolomics to the investigation of salt stress in maize (Zea mays)
Authors: Gavaghan Claire L. , Li Jia V. , Hadfield Stephen T. , Hole Stephen , Nicholson Jeremy K. , Wilson Ian D. , Howe Peter W. A. , Stanley Paul D. , Holmes Elaine
Published: December 2010

Introduction – High salinity, caused by either natural (e.g. climatic changes) or anthropic factors (e.g. agriculture), is a widespread environmental stressor that can affect development and growth of salt‐sensitive plants, leading to water deficit, the inhibition of intake of essential ions and metabolic disorders.

Objective – The application of an NMR‐based metabolic profiling approach to the investigation of saline‐induced stress in Maize plants is presented.

Methodology – Zea Maize seedlings were grown in either 0, 50 or 150 mM saline solution. Plants were harvested after 2, 4 and 6 days (n = 5 per class and time point) and 1H NMR spectroscopy was performed separately on shoot and root extracts. Spectral data were analysed and interpreted using multivariate statistical analyses.

Results – A distinct effect of time/growth was observed for the control group with relatively higher concentrations of acetoacetate at day 2 and increased levels of alanine at days 4 and 6 in root extracts, whereas concentration of alanine was positively correlated with the shoot extracts harvested at day 2 and trans‐aconitic acid increased at days 4 and 6. A clear dose‐dependent effect, superimposed on the growth effect, was observed for saline treated shoot and root extracts. This was correlated with increased levels of alanine, glutamate, asparagine, glycine‐betaine and sucrose and decreased levels of malic acid, trans‐aconitic acid and glucose in shoots. Correlation with salt‐load shown in roots included elevated levels of alanine, γ‐amino‐N‐butyric acid, malic acid, succinate and sucrose and depleted levels of acetoacetate and glucose.

Conclusions – The metabolic effect of high salinity was predominantly consistent with osmotic stress as reported for other plant species and was found to be stronger in the shoots than the roots. Using multivariate data analysis it is possible to investigate the effects of more than one environmental stressor simultaneously. Copyright © 2010 John Wiley & Sons, Ltd.
Validation of the national health insurance research database with ischemic stroke cases in Taiwan
Authors: Cheng Ching‐Lan , Kao Yea‐Huei Yang , Lin Swu‐Jane , Lee Cheng‐Han , Lai Ming Liang
Published: December 2010

Objective

The National Health Insurance Research Database (NHIRD) is commonly used for pharmacoepidemiological research in Taiwan. This study evaluated the validity of the database for patients with a principal diagnosis of ischemic stroke.

Study design and methods

This cross‐sectional study compares records in the NHIRD with those in one medical center. Patients hospitalized for ischemic stroke in 1999 were identified from both databases. The discharge notes, laboratory data, and medication orders during admission and the first discharge visit were reviewed to validate ischemic stroke diagnoses and aspirin prescribing in the NHIRD. Agreement between the two databases in comorbidities of ischemic stroke diagnosis was evaluated using ICD‐9 codes.

Results

Three hundred and seventy two cases were identified from the NHIRD; among them, 364 cases (97.85%) were confirmed as ischemic stroke by radiology examination and clinical presentation. Among these confirmed cases, 344 (94.51%) were assigned ‘ischemic stroke’ as the principal diagnosis in the NHIRD. The overall agreement of comorbid diagnoses between the databases was 48.39%. The PPV for selected conditions also varied widely, from 0.50 for fracture to 1.00 for colon cancer. The accuracy of recorded aspirin prescriptions was higher in first post‐discharge visits (PPV = 0.94) than during hospitalization (PPV = 0.88).

Conclusion

The accuracy of the NHIRD in recording ischemic stroke diagnoses and aspirin prescriptions was high, and the NHIRD appears to be a valid resource for population research in ischemic stroke. Copyright © 2010 John Wiley & Sons, Ltd.
Improvement in metformin and insulin utilisation in the Australian veteran population associated with quality use of medicines intervention programs
Authors: Gadzhanova Svetla , Roughead Elizabeth E. , Loukas Katrina , Vajda Jacqualine
Published: December 2010

Purpose

To examine the impact of 2001 and 2005 quality use of medicines (QUMs) diabetes programs implemented by National Prescribing Service (NPS) on the prevalence of utilisation of metformin and insulin among the Australian diabetes veteran population.

Methods

A retrospective observational study using Department of Veterans' Affairs pharmacy claims data. Diabetes population was defined as all veterans aged 55 and over who were dispensed medicines indicative of diabetes between 2000 and 2007. Prevalence of utilisation of metformin and insulin were assessed. Time series regression analysis was undertaken to study the effect on drug utilisation of NPS diabetes intervention programs.

Results

Of the diabetes population, over 55% has been dispensed metformin, and around 20% insulin. Across 2000–2007, metformin used as monotherapy has risen from 22.7 to 28.6% of the diabetes population and metformin concurrent with other diabetes medicines has increased from 32.3 to 36.5%. Insulin monotherapy has decreased from 13.9 to 11.5%, while insulin in combination with oral hypoglycaemics has increased from 6.1 to 11.1%. Twenty‐four months post the onset of second NPS diabetes intervention, there was 4.2% relative increase in metformin use, and 13.5% relative increase in insulin used concurrently with oral hypoglycaemics, compared to the estimates without the interventions.

Conclusions

Changes in oral hypoglycaemics trends are towards metformin dispensing as part of ongoing diabetes management. Insulin trends have been away from monotherapy and towards concurrent dispensing with oral antidiabetic drugs. NPS QUMs programs for diabetes management were positively associated with these changes. Copyright © 2010 John Wiley & Sons, Ltd.
Deposition of Thin Films from Amino Group Containing Precursors with an Atmospheric Pressure Microplasma Jet
Authors: Vogelsang Andreas , Ohl Andreas , Foest Rüdiger , Schröder Karsten , Weltmann Klaus‐Dieter
Published: December 2010

Results are presented for the deposition of amino‐functional thin films by means of an atmospheric pressure microplasma jet operated in a self‐organised discharge regime (“locked mode”). A comparative study is carried out for two precursors (cyclopropylamine and ethylenediamine) and for two surrounding atmospheres, one consisting of N2 and H2, the other being normal air. The deposition with ethylenediamine at air yields [NH2]/[C] ratios of up to 5.5%, as obtained by XPS analysis of the derivatised surfaces. The observed parameter dependencies of deposition rate and [NH2]/[C] ratio are discussed and a first model for the deposition process is proposed, taking into account e.g., the measured chemical composition of the films and substrate heating.

magnified image
First evidence of resistive switching in polycrystalline GaV4S8 thin layers
Authors: Souchier Emeline , Cario Laurent , Corraze Benoit , Moreau Philippe , Mazoyer Pascale , Estournès Claude , Retoux Richard , Janod Etienne , Besland Marie‐Paule
Published: December 2010

Recently a new type of reversible and non‐volatile resistive switching was discovered in single crystals of Mott insulators AM4X8 (A = Ga, Ge; M = V, Nb, Ta; X = S, Se). Here we report on the first synthesis of thin layers (thicknesses in the 100 to 1000 nm range) of GaV4S8 by RF magnetron sputtering process. Energy dispersive spectroscopy, X‐ray diffraction and TEM analyses attest the high quality of polycrystalline GaV4S8 thin layers. Electrical measurements demonstrate that deposited GaV4S8 thin films exhibit a non‐volatile reversible resistive switching at room temperature with writing/erasing times of ∼10 µs and a memory window (Rhigh – Rlow)/ Rlow > 33%. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
ZnO nanorods–polymer hybrid white light emitting diode grown on a disposable paper substrate
Authors: Amin G. , Zaman S. , Zainelabdin A. , Nur O. , Willander M.
Published: December 2010

We demonstrate intrinsic white light emission from hybrid light emitting diodes fabricated using an inorganic–organic hybrid junction grown at 50 °C on a paper substrate. Cyclotene was first spin coated on the entire substrate to act as a surface barrier layer for water and other nutrient solutions. The active area of the fabricated light emitting diode (LED) consists of zinc oxide nanorods (ZnO NRs) and a poly(9,9‐dioctylfluorene) (PFO) conducting polymer layer. The fabricated LED shows clear rectifying behavior and a broad band electroluminescence (EL) peak covering the whole visible spectrum range from 420 nm to 780 nm. The color rendering index (CRI) was calculated to be 94 and the correlated color temperature (CCT) of the LED was 3660 K. The low process temperature and procedure in this work enables the use of paper substrate for the fabrication of low cost ZnO–polymer white LEDs for applications requiring flexible/disposable electronic devices. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thin tantalum films on crystalline silicon – a metallic glass
Authors: Stella Kevin , Bürstel Damian , Hasselbrink Eckart , Diesing Detlef
Published: December 2010

Thin amorphous tantalum films are prepared on Si(111) substrates in a metallic glassy state. The amorphous monoatomic state of the film is characterized by X‐ray diffraction studies. The glassy state leads to a negative temperature coefficient of the resistivity (TCR) for low sample temperatures <200 K which is attributed to incipient localization. Above 200 K a positive TCR is observed as expected for a normal Boltzmann transport regime. Upon heating the Si substrate to 1200 K TaSi2 is formed out of the amorphous tantalum film and the silicon substrate. The TaSi2 layer is crystalline as evident from X‐ray diffraction data.

magnified image

Schematic drawing of the evaporation setup on either glass or silicon samples. Scheme of annealing effects.

(© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Examining improved experimental designs for wind tunnel testing using Monte Carlo sampling methods
Authors: Hill Raymond R. , Leggio Derek A. , Capehart Shay R. , Roesener August G.
Published: December 2010

Wind tunnels are used in the design and testing of a wide variety of systems and products. Wind tunnel test campaigns involve a large number of experimental data points, can take a long time to accomplish, and can consume tremendous resources. Design of Experiments is a systematic, statistically based approach to experimental design and analysis that has the potential to improve the efficiency and effectiveness of wind tunnel testing. In Defense Acquisition, wind tunnel testing of aircraft systems may require years of effort to fully characterize the system of interest. We employ data from a fairly large legacy wind tunnel test campaign and compare that data's corresponding response surface to the response surfaces derived from data generated using smaller, statistically motivated experimental design strategies. The comparison is accomplished using a Monte Carlo sampling methodology coupled with a statistical comparison of the system's estimated response surfaces. Initial results suggest a tremendous opportunity to reduce wind tunnel test efforts without losing test information. Published in 2010 by John Wiley & Sons, Ltd.
Reliability‐based design optimization of computation‐intensive models making use of response surface models
Authors: Steenackers G. , Versluys R. , Runacres M. , Guillaume P.
Published: December 2010

Design optimization can be very time‐consuming depending on the complexity of the model to be optimized. This manuscript describes the development of an adaptive response surface method for reliability‐based design optimization of computation‐intensive models, capable of reducing optimization times significantly. The method applied in this paper makes use of adaptive response surfaces for the elements of the considered objective function and probabilistic constraints. Because the optimization takes place on the response surface and not on the complex model itself, the number of function evaluations is reduced significantly. Higher order response models are used in combination with the adaptive approach. Additionally, the order of the interpolating functions can increase during successive iteration steps before the optimized design parameter values are achieved. The response model to be optimized is not built from a pre‐defined number of design experiments, as is done usually, but is adapted and refined during the optimization routine. The proposed optimization technique is evaluated on a finite element reliability‐based design optimization with multiple parameters. Copyright © 2010 John Wiley & Sons, Ltd.
Fuzzy conceptual clustering
Authors: Perner Petra , Attig Anja
Published: December 2010

Grouping unknown data into groups of similar data is a necessary first step for classification, indexing of databases, and prediction. Most of the current applications, such as news classification, blog indexing, image classification, and medical diagnosis, obtain their data in temporal sequence or online. The necessity for data exploration requires a graphical method that allows the expert in the field to study the determined groups of data. Therefore, incremental hierarchical clustering methods that can create explicit cluster descriptions are convenient. The noisy and uncertain nature of the data makes it necessary to develop fuzzy clustering methods. We propose a novel fuzzy conceptual clustering algorithm. We describe the fuzzy objective function for incremental building of the clusters and the relation among the clusters in a hierarchy. The operations that can incrementally reoptimize the fuzzy‐based hierarchy based on the newly arrived data are explained. Finally, we evaluate our method and present the results. The evaluation of the discovered concepts based on a decision tree classifier shows that the accuracy of the decision tree is very good for the fuzzy conceptual clustering algorithm compared with fuzzy c‐means and the accuracy comes close to the expert's accuracy. Copyright © 2010 John Wiley & Sons, Ltd.
Semiconductor cadmium sulphide nanoparticles as matrices for peptides and as co‐matrices for the analysis of large proteins in matrix‐assisted laser desorption/ionization reflectron and linear time‐of‐flight mass spectrometry
Authors: Kailasa Suresh Kumar , Wu Hui‐Fen
Published: December 2010

The use of semiconductor cadmium sulphide nanoparticles (CdS NPs) capped with 4‐aminothiophenol (ATP) and 11‐mercaptoundecanoic acid (MUA) is described for the first time as matrices and as co‐matrices for the analysis of peptides and proteins in matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS). UV‐visible spectroscopy, Fourier transform infrared (FT‐IR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were applied for the characterization of functionalized CdS NPs. The synthesized CdS‐ATP and CdS‐MUA NPs exhibit uniform size distribution with diameter of 15–25 nm and 20–30 nm, respectively. The ‐NH2 (ATP) and COOH (MUA) groups modified on the surfaces of CdS NPs provide ionizable moieties for efficient transfer of protons during the desorption/ionization of analytes. The functionalized CdS NPs have desirable properties for the analysis of peptides in reflectron MALDI‐TOF‐MS with suppressed background noise and increased mass resolution (4–13‐fold) in linear MALDI‐TOF‐MS. The application of CdS‐MUA NPs and SA as the co‐matrices in MALDI‐MS is demonstrated for the analysis of hydrophobic proteins from soybean. Copyright © 2010 John Wiley & Sons, Ltd.
Single drop microextraction coupled with matrix‐assisted laser desorption/ionization mass spectrometry for rapid and direct analysis of hydrophobic peptides from biological samples in high salt solution
Authors: Wu Hui‐Fen , Kailasa Suresh Kumar , Lin Chi‐Hsien
Published: December 2010

Single drop microextraction (SDME) coupled with matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) has been applied for direct analysis of hydrophobic peptides (valinomycin and gramicidin D) from biological samples (urine and plasma) in high salt solution. The optimal conditions such as selection of extraction solvent, stirring rate, extraction time, effect of salt concentration and matrix‐to‐analyte ratio were investigated. The limits of detection (LODs) were found to be 73 nM to 170 nM for valinomycin and 96 nM to 5.5 µM for gramicidin D in high salt solution (1.7 M of NaCl) in MALDI‐MS. The current approach can enhance the LODs by 11–320‐fold for gramicidin D analysis in water, urine and plasma in high salt solution. Furthermore, the current approach has been successfully demonstrated for real‐world sample analysis (β‐carotene from carrots) by MALDI‐MS. The current approach is a rapid, simple and efficient clean‐up platform for direct analysis of hydrophobic molecules in biological samples from high salt solution. Copyright © 2010 John Wiley & Sons, Ltd.
A counter‐intuitive approach to calculating non‐exchangeable 2H isotopic composition of hair: treating the molar exchange fraction fE as a process‐related rather than compound‐specific variable
Authors: Landwehr Jurate M. , Meier‐Augenstein Wolfram , Kemp Helen F.
Published: December 2010

Hair is a keratinous tissue that incorporates hydrogen from material that an animal consumes but it is metabolically inert following synthesis. The stable hydrogen isotope composition of hair has been used in ecological studies to track migrations of mammals as well as for forensic and archaeological purposes to determine the provenance of human remains or the recent geographic life trajectory of living people. Measurement of the total hydrogen isotopic composition of a hair sample yields a composite value comprised of both metabolically informative, non‐exchangeable hydrogen and exchangeable hydrogen, with the latter reflecting ambient or sample preparation conditions. Neither of these attributes is directly measurable, and the non‐exchangeable hydrogen composition is obtained by estimation using a commonly applied mathematical expression incorporating sample measurements obtained from two distinct equilibration procedures. This commonly used approach treats the fraction of exchangeable hydrogen as a mixing ratio, with a minimal procedural fractionation factor assumed to be close or equal to 1. Instead, we propose to use full molar ratios to derive an expression for the non‐exchangeable hydrogen composition explicitly as a function of both the procedural fractionation factor α and the molar hydrogen exchange fraction fE. We apply these derivations in a longitudinal study of a hair sample and demonstrate that the molar hydrogen exchange fraction fE should, like the procedural fractionation factor α, be treated as a process‐dependent parameter, i.e. a reaction‐specific constant. This is a counter‐intuitive notion given that maximum theoretical values for the molar hydrogen exchange fraction fE can be calculated that are arguably protein‐type specific and, as such, fE could be regarded as a compound‐specific constant. We also make some additional suggestions for future approaches to determine the non‐exchangeable hydrogen composition of hair and the use of standards. Copyright © 2010 John Wiley & Sons, Ltd.
Building an empirical mass spectra library for screening of organic pollutants by ultra‐high‐pressure liquid chromatography/hybrid quadrupole time‐of‐flight mass spectrometry
Authors: Díaz Ramón , Ibáñez María , Sancho Juan V. , Hernández Félix
Published: December 2010

Hybrid quadrupole time‐of‐flight mass spectrometry (QTOF MS) has gained wide acceptance in many fields of chemistry, for example, proteomics, metabolomics and small molecule analysis. This has been due to the numerous technological advances made to this mass analyser in recent years. In the environmental field, the instrument has proven to be one of the most powerful approaches for the screening of organic pollutants in different matrices due to its high sensitivity in full acquisition mode and mass accuracy measurements. In the work presented here, the optimum experimental conditions for the creation of an empirical TOF MS spectra library have been evaluated. For this model we have used a QTOF Premier mass spectrometer and investigated its functionalities to obtain the best MS data, mainly in terms of mass accuracy, dynamic range and sensitivity. Different parameters that can affect mass accuracy, such as lock mass, ion abundance, spectral resolution, instrument calibration or matrix effect, have also been carefully evaluated using test compounds (mainly pesticides and antibiotics). The role of ultra‐high‐pressure liquid chromatography (UHPLC), especially when dealing with complex matrices, has also been tested. In addition to the mass accuracy measurements, this analyser allows the simultaneous acquisition of low and high collision energy spectra. This acquisition mode greatly enhances the reliable identification of detected compounds due to the useful (de)protonated molecule and fragment ion accurate mass information obtained when working in this mode. An in‐house empirical spectral library was built for approximately 230 organic pollutants making use of QTOF MS in MSE mode. All the information reported in this paper is made available to the readers to facilitate screening and identification of relevant organic pollutants by QTOF MS. Copyright © 2010 John Wiley & Sons, Ltd.
Comparison of the isomeric α‐amino acyl adenylates and amino acid phosphoramidates of adenosine by electrospray ionization tandem mass spectrometry
Authors: Gao Xiang , Zeng Zhiping , Xu Pengxiang , Tang Guo , Liu Yan , Zhao Yufen
Published: December 2010

The isomeric α‐amino acyl adenylates and amino acid phosphoramidates of adenosine were synthesized and analyzed in detail by electrospray ionization tandem mass spectrometry (ESI‐MSn). In ESI‐MS/MS of α‐amino acyl adenylates, the novel rearrangement ion [cAMP–H]– observed as the most intense signal was formed through the pentacoordinate phosphorus intermediate with a six‐membered ring by nucleophilic attack of the 3'‐hydroxyl group on the phosphorus atom. In contrast, for the amino acid phosphoramidate of adenosine, the phosphorus atom could be attacked not only by the carboxylic group to form the cyclic aminoacyl phosphoramidates (CAPAs), but also by the nitrogen atom on the nucleobase leading to intramolecular phosphoryl group migration. It was found that the sodium ion having multidentate binding ability played an essential role in this characteristic rearrangement. The proposed mechanisms were supported by the MS/MS study, deuterium‐labeled experiments, high‐resolution tandem mass spectrometry and moderate calculations at the B3LYP/6‐31G* level. The characteristic fragmentation patterns of α‐amino acyl phosphates and amino acid phosphoramidates allows identification of stereoisomers when either the phosphorylation is at the N‐terminus or C‐terminus of amino acids. Copyright © 2010 John Wiley & Sons, Ltd.
Properties of mouse vomeronasal receptor and assessment of its role in pheromone signalling
Authors: Kannan Soundarapandian , Mareeswaran Pandi , Krishnan Muthukalingan , Achiraman Shanmugam , Spencer Neil , Nytingel Balakrishnan F.
Published: December 2010

Vomeronasal type 2 receptor (V2Rx) from Swiss mouse (Mus musculus (L.)) was analyzed by high‐resolution ion‐exchange chromatography, reversed‐phase high‐performance liquid chromatography (RP‐HPLC), matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS), Fourier transform ion cyclotron resonance mass spectrometry (FTICR‐MS), Ion Spray tandem mass spectrometry (MS/MS), 10% sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE) and 1‐aminoanthracene (1‐AMA) fluorometric assay. Vomeronasal sensory neuronal cell bound proteins were resolved into major protein peaks. Several proteins were identified and subsequently purified as the V2Rx receptor on 10% SDS‐PAGE with trace amounts of other protein bands. The molecular weight of the identified V2Rx was 109 kDa. MALDI‐TOF and micro‐sequencing experiments demonstrated that the identified V2Rx receptor shared considerable sequence similarity with vomeronasal receptor type 2 (NCBI Accession Number AB267725), which is a seven transmembrane peptide with 912 amino acid residues. The molecular characterization revealed that the N‐terminus of the V2Rx receptor contained the 11GAEAAE16 domain involved in pheromone signalling. The biometric assay (octanamine‐V2Rx binding) showed the identified V2Rx receptor and mouse sex pheromone to 2‐octanamine (methyl heptyl) in a 1:1 ratio. Uptake of odourants determined in physiological condition showed enhanced V2Rx receptors as volatile hydrophobic pheromone receptors in the vomeronasal neuron of the Swiss mouse. Copyright © 2010 John Wiley & Sons, Ltd.
Liquid chromatography/tandem mass spectrometry analysis of long‐chain oxidation products of cardiolipin induced by the hydroxyl radical
Authors: Maciel Elisabete , Domingues Pedro , Domingues M. Rosário M.
Published: December 2010

The anionic phospholipid cardiolipin (CL) is found almost exclusively in the inner membrane of mitochondria, playing an important role in energy metabolism. Oxidation of CL has been associated with apoptotic events and various pathologies. In this study, electrospray ionization mass spectrometry coupled with liquid chromatography (LC/ESI‐MS) was used to identify tetralinoleoyl‐cardiolipin (TLCL) modifications induced by the OH. radical generated under Fenton reaction conditions (H2O2 and Fe2+). The identified oxidation products of TLCL contained 2, 4, 6 and 8 additional oxygen atoms. These long‐chain oxidation products were characterized by LC/ESI‐MS/MS as doubly [M–2H]2− and singly charged [M–H]− ions. A detailed analysis of the fragmentation pathways of these precursor ions allowed the identification of hydroperoxy derivatives of CL. MS/MS analysis indicated that CL oxidation products with 4, 6 and 8 oxygen atoms have one fatty acyl chain bearing 4 oxygen atoms ([RCOO+4O]−). Even when the TLCL molecule was oxidized by the addition of eight oxygen atoms, one of the acyl chains remained non‐modified and one fatty acyl chain contained three or four oxygen atoms. This led us to conclude that under oxidative conditions by the OH. radical, the distribution of oxygens/peroxy groups in the CL molecule is not random, even when CL has the same fatty acyl chains in all the positions. Using mass spectrometry, the oxidation products have been unequivocally assigned, which may be useful for their detection in biological samples Copyright © 2010 John Wiley & Sons, Ltd.
Strategy for identification and detection of multiple oxidative modifications within proteins applied on persulfate‐oxidized hemoglobin and human serum albumin
Authors: Mörtstedt Harriet , Jeppsson Marina C. , Ferrari Giovanni , Jönsson Bo A.G. , Kåredal Monica H. , Lindh Christian H.
Published: December 2010

Oxidative stress has been suggested as an underlying mechanism of many human diseases. However, definitive evidence for this association has not been presented due to different shortcomings of the methods used to measure biomarkers of oxidative stress. Persulfates are oxidizing agents known to elicit hypersensitive reactions from the airways and skin. Despite a frequent use of persulfates at many work places, no biomarkers for persulfate exposure are available. The aim of this study was to develop a strategy for the identification and detection of multiple oxidative modifications within proteins. This strategy was applied on persulfate‐oxidized proteins to identify oxidized peptides suitable for further investigation as biomarkers of persulfate exposure or oxidative stress. A strategy for the identification and the relative quantification of multiple oxidative modifications within proteins was developed. The usage of two software packages facilitated the search for modified peptides to a great extent. Oxidized peptides were relatively quantified using liquid chromatography/tandem mass spectrometry in selected reaction monitoring mode. The result showed that persulfates oxidize tryptophans and methionines resulting in mass shifts of 16 and/or 32 Da. Also, oxidized albumin peptides in nasal lavage fluid samples from subjects challenged with persulfate were detected. The oxidation degree before and after challenge remained constant for peptides containing methionine sulfoxide. For peptides containing oxidized tryptophan the oxidation degree increased after exposure. Some of these oxidized peptides may be suitable as biomarkers; however, further evaluation is required. Copyright © 2010 John Wiley & Sons, Ltd.
Electrospray ionization mass spectrometric fragmentation of hydroquinone derivatives
Authors: Almodóvar Iriux , Ramírez‐Rodríguez Oney , Barriga Andrés , Rezende Marcos Caroli , Araya‐Maturana Ramiro
Published: December 2010

The fragmentation patterns of nine di‐, tri‐ and tetracyclic hydroquinones with potential antitumor activity were rationalized by invoking competing mechanisms that included sterically accelerated homolytic cleavage, Meerwein‐type rearrangements and dehydrations through elimination or intramolecular nucleophilic substitution. Copyright © 2010 John Wiley & Sons, Ltd.
Hydrophilic interaction liquid chromatography/tandem mass spectrometry for the analysis of diallyldimethylammonium chloride in water
Authors: Esparza X. , Moyano E. , Ventura F. , Galceran M. T.
Published: December 2010

We report a selective, sensitive and fast liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of diallyldimethylammonium chloride (DADMAC) in water. Hydrophilic interaction liquid chromatography (HILIC) was used to avoid ion‐pairing reagents, which are generally employed to retain cationic compounds. The complementary information obtained in a triple quadrupole mass spectrometer and in an ion trap Orbitrap has been used to study the fragmentation of the DADMAC cation [M]+ and for the correct assignment of the products ions. The HILIC/MS/MS method developed, using electrospray ionization in positive ion mode and selected reaction monitoring (SRM) acquisition mode, led to a reliable determination and confirmation of the DADMAC cation in water samples down to 50 ng L−1. The low detection limit achieved, in combination with the absence of matrix effects, allowed the direct analysis of samples without any pretreatment, preconcentration or clean‐up step. DADMAC was determined in samples collected in a drinking water treatment plant (DWTP) in Barcelona (Spain) and it was found in the influent at the µg L−1 level. Copyright © 2010 John Wiley & Sons, Ltd.
CO and methanol adsorption on (2 × 1)Pt(110) and ion‐eroded Pt(111) model catalysts
Authors: Matolínová Iva , Johánek Viktor , Mysliveček Josef , Prince Kevin C. , Skála Tomáš , Škoda Michal , Tsud Nataliya , Vorokhta Mykhailo , Matolín Vladimír
Published: December 2010

Methanol adsorption on ion‐sputtered Pt(111) surface exhibiting high concentration of vacancy islands and on (2 × 1)Pt(110) single crystal were investigated by means of photoelectron spectroscopy (PES) and thermal desorption spectroscopy. The measurements showed that methanol adsorbed at low temperature on sputtered Pt(111) and on (2 × 1)Pt(110) surfaces decomposed upon heating. The PES data of methanol adsorption were compared to the data of CO adsorbed on the same Pt single crystal surfaces. In the case of the sputtered Pt(111) surface, the dehydrogenation of HxCO intermediates is followed by the CO bond breakage. On the (2 × 1)Pt(110) surface, carbon monoxide, as product of methanol decomposition, desorbed molecularly without appearance of any traces of atomic carbon. By comparing both platinum surfaces we conclude that methanol decomposition occurs at higher temperature on sputtered Pt(111) than on (2 × 1)Pt(110). Copyright © 2010 John Wiley & Sons, Ltd.
Summary of ISO/TC 201 Standard: ISO 29081: 2010, surface chemical analysis—Auger electron spectroscopy—reporting of methods used for charge control and charge correction
Authors: Baer D. R.
Published: December 2010

This international standard specifies the minimum amount of information required for describing the methods of charge control and charge correction in measurements of Auger electron transitions from insulating specimens by electron‐stimulated AES to be reported with the analytical results. Information is provided in an Annex on methods that have been found useful for charge control prior to or during AES analysis. The Annex also includes a summary table of methods or approaches, ordered by simplicity of approach. A similar international standard has been published for XPS (ISO 19318: 2003(E), Surface chemical analysis—XPS—reporting of methods used for charge control and charge correction. Copyright © 2010 John Wiley & Sons, Ltd.
Changes in the surface structure of Pd/Ta2O5 by oxygen and CO studied using X‐ray Photoelectron Spectroscopy (XPS)
Authors: Seo Hyun Ook , Lee Jaeyoung , Kim Kwang‐Dae , Luo Yuan , Dey Nilay Kumar , Kim Young Dok
Published: December 2010

Behaviors of Pd structures with different thicknesses supported by Ta2O5/Ta in the reaction with oxygen and CO were studied by XPS and SEM. For the samples with a Pd thickness of 3 nm, a new low‐binding‐energy component appeared in the Pd 3d level upon O2 exposure at ∼200 °C and was reduced in intensity after a subsequent CO exposure at 150 and 200 °C. The change in the Ta 4f state could also be found upon oxygen and CO exposure, indicating that both Pd and the Ta‐oxide substrate participate in the chemical reactions. For the sample with a higher Pd thickness, a positive shift in the Pd 3d level due to the oxidation of Pd was observed after exposure to O2 at a higher temperature (280 °C). A subsequent CO exposure at ∼150 °C could not reduce Pd‐oxide layers, as confirmed by the unchanged Pd 3d spectra after CO treatment, i.e. Pd‐oxide was not reactive for CO oxidation. Copyright © 2010 John Wiley & Sons, Ltd.
Exploring the benefits of adaptive sequential designs in time‐to‐event endpoint settings
Authors: Emerson Sarah C. , Rudser Kyle D. , Emerson Scott S.
Published: December 2010

Sequential analysis is frequently employed to address ethical and financial issues in clinical trials. Sequential analysis may be performed using standard group sequential designs, or, more recently, with adaptive designs that use estimates of treatment effect to modify the maximal statistical information to be collected. In the general setting in which statistical information and clinical trial costs are functions of the number of subjects used, it has yet to be established whether there is any major efficiency advantage to adaptive designs over traditional group sequential designs. In survival analysis, however, statistical information (and hence efficiency) is most closely related to the observed number of events, while trial costs still depend on the number of patients accrued. As the number of subjects may dominate the cost of a trial, an adaptive design that specifies a reduced maximal possible sample size when an extreme treatment effect has been observed may allow early termination of accrual and therefore a more cost‐efficient trial. We investigate and compare the tradeoffs between efficiency (as measured by average number of observed events required), power, and cost (a function of the number of subjects accrued and length of observation) for standard group sequential methods and an adaptive design that allows for early termination of accrual. We find that when certain trial design parameters are constrained, an adaptive approach to terminating subject accrual may improve upon the cost efficiency of a group sequential clinical trial investigating time‐to‐event endpoints. However, when the spectrum of group sequential designs considered is broadened, the advantage of the adaptive designs is less clear. Copyright © 2010 John Wiley & Sons, Ltd.