bluuebunny/crossref_metadata_2025 huggingface dataset:
Differentiation of three pairs of Boc‐β,γ‐ and γ,β‐hybrid peptides by electrospray ionization tandem mass spectrometry
Authors: Ramesh V. , Srinivas R. , Sharma G. V. M. , Jayaprakash P. , Kunwar A. C.
Published: March 2008

A new series of Boc‐N‐β3, γ4‐/γ4, β3‐isomeric hybrid peptides (containing repeats of β3‐Caa and γ4‐Caa's, Caa = C‐linked carbo β3‐/γ4‐amino acids derived from D‐xylose) have been differentiated by both positive and negative ion electrospray ionization (ESI) ion‐trap and high resolution quadrupole time‐of‐flight/tandem mass spectrometry (Q‐TOF MS/MS). MSn of protonated isomeric peptides and [M + H − Boc + H]+ produce characteristic fragmentation involving the peptide backbone, the Boc‐group, and the side chain. The positional isomers are differentiated from one another by the presence of yn+, bn+, and other fragment ions of different m/z values. It is observed that the peptides with β‐Caa at the N‐terminus produce extensive fragmentation, whereas γ‐Caa gave rise to much less fragmentation. Peptides with γ‐Caa at the N‐terminus lose NH3, whereas this process is absent for the carbopeptides with β‐Caa at the N‐terminus. Two pairs of dipeptide diastereomers are clearly differentiated by the collision‐induced dissociation (CID) of their protonated molecules. The loss of 2‐methylprop‐1‐ene is more pronounced for Boc‐NH‐(R)‐β‐Caa‐(R)‐γ‐Caa‐OCH3 (6) and Boc‐NH‐(R)‐γ‐Caa‐(R)‐β‐Caa‐OCH3 (12), whereas it is insignificant or totally absent for its protonated diastereomeric pair Boc‐NH‐(S)‐β‐Caa‐(S)‐γ‐Caa‐OCH3 (1) and Boc‐NH‐(S)‐γ‐Caa‐(S)‐β‐Caa‐OCH3 (7). Further, ESI negative ion tandem mass spectrometry has also been found to be useful for differentiating these isomeric peptide acids. Copyright © 2008 John Wiley & Sons, Ltd.
Can electrospray ionization help the characterization of iron gall inks? Investigation on the interactions of gallic acid with iron ions in aqueous solutions
Authors: Lutui Marie‐Anne , Gilard Françoise , Sablier Michel
Published: March 2008

In the present work, an investigation has been conducted by electrospray ionization (ESI) experiments to characterize the structures of iron gall ink complexes in solution. Simple mono and polyphenolic acid molecules added to iron sulfate salts were chosen to model the recipes of ink composition. Theoretical calculations have been used (1) to determine the stability of the ionic complexes generated in the gas phase, (2) to explain which structures are more likely generated in the electrospray ion source, and (3) to determine which mechanisms are likely involved in their formation. Fragmentation pathways of the derived structures have also been investigated and rationalized to facilitate the interpretation of the data obtained under collisionally induced dissociation (CID) conditions.

The present study confirms the assumption that ESI experiments with ions that are preformed in solution must be considered carefully. As a matter of fact, the study of ion formation mechanisms in the ion source is necessary to establish relationships between the ion structures in the condensed phase and the gas phase. Copyright © 2008 John Wiley & Sons, Ltd.
Toward a strategic framework of mobile knowledge management
Authors: Zhang Zuopeng (Justin) , Jasimuddin Sajjad M.
Published: March 2008

Organizations are challenged to seek efficient and effective ways of implementing knowledge management strategies in an increasingly mobile environment. Building upon ourCLIC(conservation, leverage, integration, and combination) framework of mobile knowledge management (mKM) strategies, we investigate the implementation of mKM strategies from a system perspective. An attempt is also made to formulate a decision table based upon three dimensions of knowledge properties (tacitness, location, and mobility) and then the best knowledge management strategy under each scenario is proposed. Finally, different types of hierarchies of mKM systems are identified and the selection of an appropriate hierarchy for different types of companies is elaborated. The paper provides a solid foundation for future research in mKM as well as a valuable guidance for practical managers to strategically manage mobile knowledge assets. Copyright © 2008 John Wiley & Sons, Ltd.
Is the relatively low intake of omega‐3 fatty acids in Western diet contributing to the obesity epidemics?
Authors: Strandvik Birgitta , Eriksson Susanne , Garemo Malin , Palsdottir Vilborg , Sampels Sabine , Pickova Jana
Published: March 2008

Alongside the increase of overweight and obesity in the world there is the avoidance of saturated fat and an increased dietary use of vegetable oils rich in omega‐6 fatty acids. These changes result in a marked increase of the omega‐6/omega‐3 ratio and there is increasing evidence that this changed balance is related to lifestyle diseases. There are also indications that this balance between fatty acids may be involved in epigenetics, i. e. that it influences metabolic pathways during intra‐uterine or early life which cause diseases later in life. Such processes would be a possible explanation for the epidemic outburst of obesity during the latest decades.
Tomatoes and prostate health
Authors: Stanley John C.
Published: March 2008

Prostate cancer is the most commonly diagnosed cancer in men and benign prostate hyperplasia is an increasingly common condition. There is evidence that the consumption of tomatoes and tomato based foods is associated with a reduced risk of developing prostate cancer. While the effects of tomatoes and tomato based foods are frequently explained in terms of their lycopene content other components of tomatoes may play a role. A recent highly critical review of the evidence by the FDA concluded that there was no credible evidence linking lycopene consumption to prostate cancer risk and only limited evidence linking tomato consumption to prostate cancer risk. However, the ability of the prostate to concentrate lycopene suggests a special relationship between the health of this tissue and tomato consumption. More research is needed in this area particularly on benign prostate hyperplasia.
Glycidyl‐Methacrylate‐Based Electrospun Mats and Catalytic Silver Nanoparticles
Authors: Demir Mustafa M. , Uğur Gökçe , Gülgün Mehmet Ali , Menceloğlu Yusuf Z.
Published: March 2008

P(AN‐GMA) and PGMA fibers coated with monodisperse silver nanoparticles have been prepared by a combination of electrospinning and electroless plating. The morphology of the electrospun fibers remains unchanged after surface hydrazination. Oxidation of hydrazine in an ammoniacal solution of AgNO3 reduces and deposits silver atoms along the fiber surface, which then coalesce to Ag particles. The size of the silver nanoparticles is varied between 20–60 nm. Since the density of the active sites for silver reduction is lower in P(AN‐GMA), a smaller particle size could be obtained. The catalytic activity of the silver nanoparticles has been confirmed.

magnified image
Macromol. Chem. Phys. 5/2008
Authors: Demir Mustafa M. , Uğur Gökçe , Gülgün Mehmet Ali , Menceloğlu Yusuf Z.
Published: March 2008

Cover: Silver nanoparticles were prepared on submicron diameter glycidylmethacylate‐based electrospun fibers via a redox reaction taking place between immobilized hydrazine and silver cation in solution. Catalytic activity of the nanoparticles was qualitatively confirmed employing a reduction reaction of methylene blue dye. Further details can be found in the article by M. M. Demir,* G. Uğur, M. A. Gülgün, and Y. Z. Menceloğlu on page 508.
Electron ionization time‐of‐flight mass spectrometry: Historical review and current applications
Authors: Mirsaleh‐Kohan Nasrin , Robertson Wesley D. , Compton Robert N.
Published: March 2008

This review presents an overview of electron ionization time‐of‐flight mass spectroscopy (EITOFMS), beginning with its early development to the employment of modern high‐resolution electron ionization sources. The EITOFMS is demonstrated to be ideally suited for analytical and basic chemical physics studies. Studies of the formation of positive ions by electron ionization time‐of‐flight mass spectroscopy have been responsible for many of the known ionization potentials of molecules and radicals, as well as accepted bond dissociation energies for ions and neutral molecules. The application of TOFMS has been particularly important in the area of negative ion physics and chemistry. A wide variety of negative ion properties have been discovered and studied by using these methods including: autodetachment lifetimes, metastable dissociation, Rydberg electron transfer reactions and field detachment, SF6 Scavenger method for detecting temporary negative ion states, and many others. © 2008 Wiley Periodicals, Inc. Mass Spec Rev 27: 237–285, 2008
Binding of heterocyclic aromatic amines by lactic acid bacteria: Results of a comprehensive screening trial
Authors: Stidl Reinhard , Sontag Gerhard , Koller Verena , Knasmüller Siegfried
Published: March 2008

Aim of the present study was a comprehensive investigation of the detoxification capacities of lactic acid bacteria (LAB) towards heterocyclic aromatic amines (HCA) formed during cooking of meat. It has been postulated that LAB prevent genotoxic and/or carcinogenic effects of HCA in laboratory rodents and humans via direct binding mechanisms. We measured the removal of the most abundant cooked food mutagens (AαC, PhIP, IQ, MeIQx, DiMeIQx) by eight LAB species. From each species, twelve strains were tested in liquid binding experiments with HPLC coupled with coulometric electrode array detection. The highest removal rates were observed with the representatives of the L. helveticus and S. thermophilus groups, which were seven to eight times more effective than L. kefir and L. plantarum. Strong and statistically significant differences were seen in the binding behaviour of the individual amines, the ranking order of detoxification being AαC > DiMeIQx > MeIQx > IQ > PhIP. Results of Salmonella/microsome assays with strain TA98 showed that the binding of AαC and PhIP to LAB correlates with the reduction of their mutagenic activities. This study may contribute to the development of strategies concerning the adverse health effects of HCA utilizing highly protective LAB for the production of fermented foods.
A study on the use of empirical models to predict the formation of acrylamide in potato crisps
Authors: Knol Jeroen J. , Viklund Gunilla Å. I. , Linssen Jozef P. H. , Sjöholm Ingegerd M. , Skog Kerstin I. , van Boekel Martinus A. J. S.
Published: March 2008

The formation of acrylamide in potato crisps was fitted by empirical mathematical models. Potato slices were fried under the same experimental conditions for different times. Besides the content of precursors in the raw potato slices, acrylamide and water content in the potato crisps were quantified after predetermined times (2–6 min). The temperature developments in the surrounding oil and outer cell layer of the potato slices were monitored, giving more insight in the frying process and making future comparisons between studies possible. The pattern found for the formation of acrylamide, which was similar to earlier studies, was fitted to three empirical models. Statistical methods were used to compare the performance of the models, with the “Logistic‐Exponential” and “Empirical” model performing equally well. The obtained model parameters were in the range of earlier reported studies, although this comparison is not unequivocal as the experimental conditions differed between studies. The precision of parameter estimates was problematic; this should be improved by better experimental design. Nevertheless, the approach of this study will make it possible to truly compare acrylamide formation patterns and model parameters in the future, with the ability to develop a tool to predict acrylamide formation in potato crisps.
Approximation capability of a bilinear immersed finite element space
Authors: He Xiaoming , Lin Tao , Lin Yanping
Published: March 2008

This article discusses a bilinear immersed finite element (IFE) space for solving second‐order elliptic boundary value problems with discontinuous coefficients (interface problem). This is a nonconforming finite element space and its partition can be independent of the interface. The error estimates for the interpolation of a Sobolev function indicate that this IFE space has the usual approximation capability expected from bilinear polynomials. Numerical examples of the related finite element method are provided. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2008
Somnolence effects of antipsychotic medications and the risk of unintentional injury
Authors: Said Qayyim , Gutterman Elane M. , Kim Myoung S. , Firth Sean D. , Whitehead Richard , Brixner Diana
Published: March 2008

Purpose

This study examined the relationship between antipsychotic medications, categorized by published somnolence effects, and unintentional injury (UI).

Methods

The study population included patients of 18–64 years of age in a healthcare insurance database with claims from 2001 to 2004 and diagnoses of schizophrenia or affective disorder. A nested case‐control design was used with cases defined by an E‐code claim (a specified external cause of injury) for selected UIs. For cases, the index date referred to the first injury. For controls, the “control index date” was the date of claim if there was only a single medical claim; for patients with ≥2 claims, one was selected at random as the “control index date.” Both groups had a prescription for a first‐generation antipsychotic (FGA) or second‐generation antipsychotic (SGA) overlapping the index date. Potential somnolence effects were defined as: low (referent) – aripiprazole/ziprasidone; medium – risperidone; high – olanzapine/quetiapine: or any single FGA. Logistic regression models were used to estimate odds ratio (OR) and 95% confidence interval (CI) for UI, adjusted for gender, age, concomitant drug, and psychiatric diagnosis.

Results

Among 648 cases and 5214 controls, high‐somnolence SGAs were associated with an OR of 1.41 95%CI (1.03–1.93) for risk of UI, while medium‐somnolence SGAs, and FGAs had ORs of 1.17 95%CI (0.83–1.64) and 1.17 95%CI (0.79–1.74), respectively. When quetiapine and olanzapine were disaggregated, ORs were 1.61 95%CI (1.15–2.25) and 1.25 95%CI (0.89–1.74), respectively.

Conclusions

High‐somnolence SGAs may lead to UI among patients. When prescribing antipsychotics, clinicians should consider potential somnolence. Copyright © 2008 John Wiley & Sons, Ltd.
Structure‐based prediction of transcription factor binding sites using a protein‐DNA docking approach
Authors: Liu Zhijie , Guo Jun‐Tao , Li Ting , Xu Ying
Published: March 2008

Accurate identification of transcription factor binding sites is critical to our understanding of transcriptional regulatory networks. To overcome the issue of high false‐positive predictions that trouble the sequence‐based prediction techniques, we have developed a structure‐based prediction method that takes into consideration of interactions between the amino acids of a transcription factor and the nucleotides of its DNA binding sequence at structural level, along with an efficient protein‐DNA docking algorithm. The docked structures between a protein and a DNA are evaluated using a knowledge‐based energy function, in conjunction with van der Waals energy. Our docking algorithm supports quasi‐flexible docking, overcoming a number of limiting issues faced by similar docking algorithms. Our rigid‐body docking algorithm is tested on a dataset of 141 nonredundant transcription factor‐DNA complex structures. The test results show that 63.1% of the 141 complex structures are reconstructed with accuracies better than 1.0 Å RMSDs (root mean square deviation) and 79.4% of the complexes are predicted with accuracies better than 3.0 Å RMSDs when using the native DNA structures. Our quasi‐flexible docking algorithm, assuming that the DNA structures are not known, is tested on a separate set of 45 transcription factor‐DNA complexes, of which 57.8% of the docked complex conformations achieve better than 1.0 Å RMSDs while 71.1% of the complexes have RMSDs less than 3.0 Å. We have also applied our method to predict the binding motifs of the ferric uptake regulator in E. coli and showed that most of the experimentally identified sites can be predicted accurately. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Identification of proteins interacting with protein arginine methyltransferase 8: The Ewing sarcoma (EWS) protein binds independent of its methylation state
Authors: Pahlich Steffen , Zakaryan Rouzanna P. , Gehring Heinz
Published: March 2008

Protein arginine methylation is a eukaryotic posttranslational modification that plays a role in transcription, mRNA splicing and transport, in protein–protein interaction, and cell signaling. The type I protein arginine methyltransferase (PRMT) 8 is the only member of the human PRMT family that is localized at the cell membrane and its endogenous substrates have remained unknown as yet. Although PRMT8 was supposed to be expressed only in brain tissue, its presence in HEK 293 (T) cells could be demonstrated. We identified more than 20 PRMT8‐binding partners in pull‐down experiments using recombinant PRMT8 as bait followed by mass spectrometric identification of the bound proteins. Among the extracted proteins were several heterogeneous nuclear ribonucleoproteins (hnRNP), RNA‐helicases (DEAD box proteins), the TET‐family proteins TLS, Ewing's sarcoma (EWS), and TAFII68, and caprin, which all contain RGG methylation motifs and are potential substrates of PRMT8. Additionally, actin, tubulin, and heat shock proteins belong to the identified proteins. The interaction between PRMT8 and the EWS protein was characterized in more detail. Although binding of endogenous and recombinant EWS protein to PRMT8 as well as colocalization in HEK cells was observed, in vitro methylation assays revealed a rather poor methyltransferase activity of PRMT8 towards the EWS protein and a synthetic RGG‐rich reference peptide (Km, 1.3 μM; kcat/Km, 2.8 × 10−4 μM−1 s−1) in comparison to PRMT1 (Km, 0.8 μM; kcat/Km, 8.1 × 10−3 μM−1 s−1). In contrast, substrate proteins within a cell extract could be methylated by PRMT8 as efficient as by PRMT1. The main interaction site of the EWS protein with PRMT8 was determined to be the C‐terminal RGG box 3. Remarkably, complete methylation of the EWS protein did not abrogate the binding to PRMT8, pointing to an adapter role of PRMT8 for nuclear proteins at the cell membrane in addition to its methyltransferase activity. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Calcineurin B‐like domains in the large regulatory α/β subunits of phosphorylase kinase
Authors: Carrière Cathelène , Mornon Jean‐Paul , Venien‐Bryan Catherine , Boisset Nicolas , Callebaut Isabelle
Published: March 2008

Phosphorylase kinase (PhK) is a large hexadecameric complex that catalyzes the phosphorylation and activation of glycogen phosphorylase (GP). It consists in four copies each of a catalytic subunit (γ) and three regulatory subunits (α β δ). δ corresponds to endogenous calmodulin, whereas little is known on the molecular architecture of the large α and β subunits, which probably arose from gene duplication. Here, using sensitive methods of sequence analysis, we show that the C‐terminal domain (named domain D) of these α and β subunits can be significantly related to calcineurin B‐like (CBL) proteins. CBL are members of the EF‐hand family that are involved in the regulation of plant‐specific kinases of the CIPK/PKS family, and relieve autoinhibition of their target kinases by binding to their regulatory region. The relationship highlighted here suggests that PhK α and/or β domain D may be involved in a similar regulation mechanism, a hypothesis which is supported by the experimental observation of a direct interaction between domain D of PhKα and the regulatory region of the γ subunit. This finding, together the identification of significant similarities of domain D with the preceding domain C, may help to understand the molecular mechanism by which PhK α and/or β domain D might regulate PhK activity. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Enzymatic characterization and crystal structure analysis of the D‐alanine‐D‐alanine ligase from Helicobacter pylori
Authors: Wu Dalei , Zhang Liang , Kong Yunhua , Du Jiamu , Chen Shuai , Chen Jing , Ding Jianping , Jiang Hualiang , Shen Xu
Published: March 2008

D‐Alanine‐D‐alanine ligase is the second enzyme in the D‐Ala branch of bacterial cell wall peptidoglycan assembly, and recognized as an attractive antimicrobial target. In this work, the D‐Ala‐D‐Ala ligase of Helicobacter pylori strain SS1 (HpDdl) was kinetically and structurally characterized. The determined apparent Km of ATP (0.87 μM), the Km1 (1.89 mM) and Km2 of D‐Ala (627 mM), and the kcat (115 min−1) at pH 8.0 indicated its relatively weak binding affinity and poor catalytic activity against the substrate D‐Ala in vitro. However, by complementary assay of expressing HpDdl in Escherichia coli Δddl mutant, HpDdl was confirmed to be capable of D‐Ala‐D‐Ala ligating in vivo. Through sequence alignment with other members of the D‐Ala‐D‐X ligase superfamily, HpDdl keeps two conservatively substituted residues (Ile16 and Leu241) and two nonconserved residues (Leu308 and Tyr311) broadly located in the active region of the enzyme. Kinetic analyses against the corresponding HpDdl mutants (I16V, L241Y, L241F, L308T, and Y311S) suggested that these residues, especially Leu308 and Tyr311, might partly contribute to the unique catalytic properties of the enzyme. This was fairly proved by the crystal structure of HpDdl, which revealed that there is a 310‐helix (including residues from Gly306 to Leu312) near the D‐Ala binding region in the C‐terminal domain, where HpDdl has two sequence deletions compared with other homologs. Such 310‐helix may participate in D‐Ala binding and conformational change of the enzyme. Our present work hopefully provides useful information for understanding the D‐Ala‐D‐Ala ligase of Helicobacter pylori. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Effects of external interactions on protein sequence‐structure relations of beta‐trefoil fold
Authors: Li Mingfeng , Huang Yanzhao , Xiao Yi
Published: March 2008

Proteins with symmetric structures are ideal models to investigate the sequence‐structure relations. We investigate proteins with β‐trefoil fold and find they have different degrees of sequence symmetries although they show similar symmetric structures. To understand this, we calculate the strength of interactions of the β‐trefoil folds with surrounding environments and find the low degrees of sequence symmetries are often correlated with large external interactions. Our results give an additional confirmation of Anfinsen's thermodynamic hypothesis that protein structures are not only determined by their sequences but also by their surrounding environments. We suggest the external interactions should be considered additionally in protein structure prediction through ab initio folding. Proteins 2008. © 2008 Wiley‐Liss, Inc.
The life and work of Guy Newton (1919–1969)
Authors: Jones John
Published: March 2008

An account is given of the life and work of G.G.F. Newton (1919–1969), joint discoverer with E.P. Abraham (1913–1999) of cephalosporin C. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
Metabolism of olaquindox in rat liver microsomes: structural elucidation of metabolites by high‐performance liquid chromatography combined with ion trap/time‐of‐flight mass spectrometry
Authors: Liu Zhaoying , Huang Lingli , Dai Menghong , Chen Dongmei , Wang Yulian , Tao Yanfei , Yuan Zonghui
Published: March 2008

Olaquindox (N‐(2‐hydroxyethyl)‐3‐methyl‐2‐quinoxalincarboxamide‐1,4‐dioxide) is a growth‐promoting feed additive for food‐producing animals. Its toxicity is closely related to the metabolism. The complete metabolic pathways of olaquindox are not revealed. To improve studies of the metabolism and toxicity of olaquindox, its biotransformation in rat liver microsomes and the structure of its metabolites using high‐performance liquid chromatography combined with ion trap/time‐of‐flight mass spectrometry (LC/MS‐ITTOF) were investigated. When olaquindox was incubated with an NADPH‐generating system and rat liver microsomes, ten metabolites (M1–M10) were detected. The structures of these metabolites were identified from mass spectra and comparison of their changes in their accurate molecular masses and fragment ions with those of the parent drug. With the high resolution and good mass accuracy achieved by this technique, the elemental compositions of the metabolites and their fragment ions were exactly determined. The results indicate that the N → O group reduction is the main metabolic pathway of olaquindox metabolism in rat liver microsomes, because abundant 1‐desolaquindox (M2), 4‐desolaquindox (M1) and bisdesoxyolaquindox (M9) were produced during the incubation step. Seven other minor metabolites were revealed which were considered to be hydroxylation metabolites, based on the position of the quinoxaline ring or 3‐methyl group and a carboxylic acid derivative on the side chain at position 2 of the quinoxaline ring. Among the identified metabolites, five new hydroxylated metabolites (M3–M7) were found for the first time in rat liver microsomes. This work will conduce to complete clarification of olaquindox metabolism, and improve the in vivo metabolism of olaquindox in food animals. Copyright © 2008 John Wiley & Sons, Ltd.
Quantitative determination of progesterones and corticosteroids in human urine using gas chromatography/mass spectrometry: application to pelvic organ prolapse patients
Authors: Shama Naz , Bai Sang Wook , Chung Bong Chul , Jung Byung Hwa
Published: March 2008

A quantitative analytical method using gas chromatography/mass spectrometry (GC/MS) to determine urinary concentrations of eight progesterones and corticosteroids has been developed. After enzymatic hydrolysis with β‐glucouronidase/arylsulfatase, urine samples were extracted by simple one‐step solid‐phase extraction. Obtained extracts were derivatized with a mixture of N‐methyl‐N‐(trimethylsilyl)trifluoroacetamide/ammonium iodide/dithiothreitol and determined by GC/MS in selected ion monitoring mode to increase the sensitivity. d4‐Cortisol and d9‐progesterone were used as internal standards for two different steroid groups. The linear correlation coefficient was in the range of 0.9913 to 0.9998 and recoveries were over 80% for all compounds. Precision and accuracy were in the range of 0.9–18.1 and 84.1–118.7%, respectively. The limit of quantitation (LOQ) was 10 ng/mL for 11‐deoxycorticosterone and 21‐deoxycortisol and 5 ng/mL for all other analytes. The developed method was successfully applied on pelvic organ prolapsed patients (n = 10, age: 67.9 ± 4.9) and post‐menopausal (n = 10, age: 63.6 ± 5.5) control women. Urinary levels of most progesterones and corticosteroids except 11‐deoxycorticosterone decreased but only that of 17α‐hydroxyprogesterone significantly decreased in patients compared with the control groups. Thus, it is concluded that progesterones could be a factor in the pathogenesis of pelvic organ prolapse, and, among them, 17α‐hydroxyprogesterone could be a biomarker for pelvic organ prolapse. Copyright © 2008 John Wiley & Sons, Ltd.
Gas chromatography/mass spectrometry analysis of triacetone triperoxide (TATP) degradation products
Authors: Armitt David , Zimmermann Peter , Ellis‐Steinborner Simon
Published: March 2008

Interest in the analysis and detection of triacetone triperoxide (TATP) and other organic peroxides has increased in recent years. Also of interest is the degradation and decomposition of the peroxides, not only to gain more detailed chemical information from organic peroxide samples, but also to investigate possible new procedures or mechanisms for chemical neutralisation. This report investigates the chemical degradation products of TATP after it has been treated with different acids within a sealed system over a period of 14 days. The samples were collected and analysed by solid‐phase microextraction (SPME) and direct liquid injection gas chromatography/mass spectrometry (GC/MS). The results of the experiments indicate that the rate of chemical degradation of TATP and the products formed are dependent on the type of acid. The observed differences enables the type of acid used in the degradation process to be determined, provide complementary information to identify the presence of TATP, and possibly indicate new pathways that may be used to chemically neutralise TATP. Copyright © 2008 Commonwealth of Australia. Published by John Wiley & Sons, Ltd.
Chemical derivatization of peptides containing phosphorylated serine/threonine for efficient ionization and quantification in matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Tsumoto Hiroki , Ra Moonjin , Samejima Keijiro , Taguchi Ryo , Kohda Kohfuku
Published: March 2008

We describe a useful method for the efficient ionization and relative quantification of peptides containing serine/threonine phosphorylation sites. This method is based on β‐elimination of the phosphate group from serine/threonine phosphorylation sites under alkaline conditions, followed by Michael addition reaction with N‐(2‐mercaptoethyl)‐6‐methylnicotinamide (MEMN). As a result of the derivatization reaction, the negatively charged phosphate group is substituted with the nicotinoyl moiety to improve the ionization efficiency of the derivatized peptide. The combination of d3‐labeled MEMN (d3‐MEMN) and MEMN (d0‐MEMN) generates a 3 Da mass difference between d3‐MEMN‐labeled and d0‐MEMN‐labeled peptides, which is a useful signature for the identification of peptides containing serine/threonine phosphorylation sites in the matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrum. Moreover, the mass difference is useful for the quantitative analysis of serine/threonine phosphorylation in proteins. In this paper, we describe the synthesis of d0/d3‐labeled MEMN and an application of our approach to model peptides and proteins. Copyright © 2008 John Wiley & Sons, Ltd.
Dual negative precursor ion scan approach for rapid detection of glutathione conjugates using liquid chromatography/tandem mass spectrometry
Authors: Mahajan Mukesh K. , Evans Christopher A.
Published: March 2008

Screening for conjugates formed by the tripeptide glutathione with new chemical entities is an essential step during the drug discovery process, as the formation of these conjugates serves as an indicator for the presence of reactive electrophilic intermediates. To increase the selectivity and throughput of this analysis, various mass spectral scan types have evolved over time. Historically, samples were analyzed under positive ionization conditions for the neutral loss ofm/z129 (loss of the pyroglutamic acid moiety from glutathione); however, more recently, negative precursor ion scanning for the loss ofm/z272 (deprotonatedγ‐glutamyl‐dehydroalanyl‐glycine from glutathione) has emerged as a more selective tool. Further increasing the selectivity, we report on an extension of this methodology by incorporating a simultaneous dual negative precursor ion scan for two commonly observed ion fragments from glutathione conjugates,m/z272 and 254 (the dehydrated form ofm/z272). This negative dual precursor ion scan methodology was first validated using substrates known to undergo metabolic bioactivation (diclofenac, carbamazepine, and 3‐methyl indole) and has then been applied to the routine analysis of proprietary compounds undergoing active lead optimization. In comparison to alternative scan methodologies, the increased selectivity offered by this simultaneous dual precursor method results in a reduction in the generation of false positive results as well as reduced data interpretation time. Copyright © 2008 John Wiley & Sons, Ltd.
Classification of vegetable oils according to their botanical origin using sterol profiles established by direct infusion mass spectrometry
Authors: Lerma‐García María J. , Ramis‐Ramos Guillermo , Herrero‐Martínez José M. , Simó‐Alfonso Ernesto F.
Published: March 2008

A simple and quick method to classify vegetable oils according to their botanical origin, based on direct infusion of sterol extracts into a mass spectrometer, was developed. Using mass spectrometry (MS) with either an electrospray ionization or an atmospheric pressure photoionization source, followed by linear discriminant analysis of the mass spectral data, oil samples corresponding to eight different botanical origins were perfectly classified with an excellent resolution among all the categories. An excellent correlation between the sterol profiles obtained by MS and by the official gas chromatography (with flame ionization detection) method was obtained. Thus, the proposed method is a promising alternative for sterol fingerprinting of vegetable oils, with the advantage that prior chromatographic separation is not required. Copyright © 2008 John Wiley & Sons, Ltd.
Direct analysis of illicit drugs by desorption atmospheric pressure photoionization
Authors: Kauppila Tiina J. , Arvola Ville , Haapala Markus , Pól Jaroslav , Aalberg Laura , Saarela Ville , Franssila Sami , Kotiaho Tapio , Kostiainen Risto
Published: March 2008

The feasibility of desorption atmospheric pressure photoionization (DAPPI) in the direct analysis of illicit drugs was demonstrated by the analysis of confiscated drug samples of various forms such as tablets, blotter paper, and plant resin and bloom. 3,4‐Methylenedioxymethamphetamine (MDMA), amphetamine, phenazepam, and buprenorphine were detected from the analyzed tablets, lysergic acid diethylamide (LSD) and bromobenzodifuranylisopropylamine (bromo‐Dragonfly, ABDF) from blotter paper, and Δ9‐tetrahydrocannabinol (THC) and cannabinol from Cannabis Sativa bloom and resin. The amphetamines, phenazepam and ABDF showed protonated molecules independent of the solvent used, whereas buprenorphine, LSD and the cannabinoids showed molecular ions with toluene and protonated molecules with acetone as the solvent. Copyright © 2008 John Wiley & Sons, Ltd.
Robotic system for no‐scar gastrointestinal surgery
Authors: Phee S. J. , Low S. C. , Sun Z. L. , Ho K. Y. , Huang W. M. , Thant Z. M.
Published: March 2008

Introduction

Flexible endoscopy allows diagnostic and therapeutic interventions on the gastrointestinal (GI) tract. Simple procedures can be performed endoscopically using currently available tools. More advanced endoscopic surgical interventions are much desired and anticipated, yet they await improvements in instrumentation.

Methods

Presented here is a master–slave robotic system designed for use with flexible endoscopy. The slave is a cable‐driven flexible robotic manipulator that can be attached to an endoscope, allowing two‐handed endoscopic manipulation with 9–12 degrees of freedom (DOF).

Results

Feasibility has been demonstrated in a porcine intragastric model.

Conclusions

Further studies should determine whether this novel device can overcome some of the instrumentation‐related challenges that have heretofore limited the development of natural orifice transluminal endoscopic surgery (NOTES). Copyright © 2008 John Wiley & Sons, Ltd.
Dynamic Variations in Adhesion of Self‐Assembled Monolayers on Nanoasperities Probed by Atomic Force Microscopy
Authors: Xu Chang , Jones Ryan L. , Batteas James D.
Published: March 2008

Octadecyltriethoxysilane (OTE) self‐ assembled monolayers (SAMs) and their effects on friction and adhesion have been investigated on various combinations of functionalized and unfunctionalized silicon oxide surfaces including the oxidized surface of crystalline Si(100), silica nanoparticle films, and oxidized Si atomic force microscopy (AFM) tips. Force‐distance spectroscopy was utilized to probe and compare the properties of the OTE SAMs on silica asperities with nanoscale curvature against these same monolayers on surfaces with sub‐1 nm roughness (flat surfaces). It was found that adhesion between SAMs and silicon oxide surfaces can vary significantly when assembly takes place on surfaces with nanoscopic curvature as compared to flat surfaces. Observations indicate that the SAM structure present during force measurements is dynamic in nature, which yields different adhesion values when measured with variations of both tip‐sample contact time and tip‐approach/retract rates. These results point the need in reporting a number of measurement parameters when probing adhesion by SAM functionalized tips. SCANNING 30: 000–000, 2008. © 2008 Wiley Periodicals, Inc.
Morphology and Amine Accessibility of (3‐Aminopropyl) Triethoxysilane Films on Glass Surfaces
Authors: Wang Wei , Vaughn Mark. W.
Published: March 2008

3‐Aminopropyl) triethoxysilane (APTES) is commonly used to functionalize glass substrates because it can form an amine‐reactive film that is tightly attached to the surface. In this study, we investigated the morphology and chemical reactivity of APTES films prepared on glass substrates using common deposition techniques. Films were prepared using concentrated vapor‐phase deposition, dilute vapor‐phase deposition, anhydrous organic‐phase deposition and aqueous‐phase deposition. All films were annealed, or cured, at 150 °C. The morphology of the films was quantified by fluorescence and by atomic force microscopy (AFM). The optical equivalent of the AFM images was computed and then used to directly compare optical and AFM images. Reactive amine density was determined by a picric acid assay and by a method that employed N‐succinimidyl 3‐[2‐pyridyldithio]‐propionamido (SPDP) cross‐linked rhodamine. Fluorescence and AFM images showed that silane films prepared from dilute vapor‐phase and aqueous‐phase deposition were more uniform and had fewer domains than those deposited by the other methods. The ratio of picric acid‐accessible amino groups to SPDP cross‐linked rhodamine‐accessible groups varied with the preparation method, suggesting reactant size‐dependent difference in amine accessibility. We found a larger number of accessible amino groups on films prepared by vapor‐phase deposition than on those prepared from solution deposition. The dilute vapor‐phase deposition technique produced relatively few domains, and it should be a good choice for bioconjugation applications. There were appreciable differences in the films produced by each method. We suggest that these differences originate from differences in film rearrangement during annealing. SCANNING 30: 000–000, 2008. © 2008 Wiley Periodicals, Inc.
PISA test items and school textbooks related to science: A textual comparison
Authors: Hatzinikita Vassilia , Dimopoulos Kostas , Christidou Vasilia
Published: March 2008

The paper compares the nature of the textual construction of the Programme for International Student Assessment (PISA) science test items and the Greek school science textbooks. This nature is determined by the interplay of the notions of classification (content specialization) and formality (code specialization) modulated by both the linguistic and the visual expressive modes. The results of the relevant analysis showed that the textual materials employed in PISA and in school textbooks are oppositional in nature. Specifically, while the linguistic mode of the PISA items tends to resemble texts falling within the public domain (nonspecialized content and code), the corresponding visual mode tends to resemble texts of the esoteric domain (specialized content and code) thus familiarizing students with the specialized conventions and ways of representing entities falling within the realm of technoscientific knowledge. On the other hand, school science textbooks tend to employ the linguistic and the visual mode in exactly the opposite way. These differences between PISA science items and school science textbooks could contribute to a disorientation of the students in relation to what is expected in each specific context. This disparity could potentially be one of the factors explaining the low level of Greek students' attainment in PISA. © 2008 Wiley Periodicals, Inc. Sci Ed 92:664–687, 2008
A more powerful exact test of noninferiority from binary matched‐pairs data
Authors: Lloyd Chris J. , Moldovan Max V.
Published: March 2008

Assessing the therapeutic noninferiority of one medical treatment compared with another is often based on the difference in response rates from a matched binary pairs design. This paper develops a new exact unconditional test for noninferiority that is more powerful than available alternatives. There are two new elements presented in this paper. First, we introduce the likelihood ratio statistic as an alternative to the previously proposed score statistic of Nam (Biometrics 1997; 53:1422–1430). Second, we eliminate the nuisance parameter by estimation followed by maximization as an alternative to the partial maximization of Berger and Boos (Am. Stat. Assoc. 1994; 89:1012–1016) or traditional full maximization. Based on an extensive numerical study, we recommend tests based on the score statistic, the nuisance parameter being controlled by estimation followed by maximization. Copyright © 2008 John Wiley & Sons, Ltd.
Assessing the association between environmental impacts and health outcomes: A case study from Florida
Authors: Young Linda J. , Gotway Carol A. , Yang Jie , Kearney Greg , DuClos Chris
Published: March 2008

The Centers for Disease Control and Prevention (CDC) created the Environmental Public Health Tracking (EPHT) program to integrate hazard monitoring, exposure, and health effects surveillance into a cohesive tracking network. Part of Florida's effort to move toward implementation of EPHT is to develop models of the spatial and temporal association between myocardial infarctions (MIs) and ambient ozone levels in Florida. Existing data were obtained from Florida's Agency for Health Care Administration, Florida's Department of Environmental Protection, the U.S. Census Bureau, and CDC's Behavioral Risk Factor Surveillance System. These data were linked by both ignoring spatial support and using block kriging, a support‐adjusted approach. The MI data were indirectly standardized by age, race/ethnicity, and sex. The state of Florida was used as the comparison standard to compute the MI standardized event ratio (SER) for each county and each month. After the data were linked, global models were used initially to relate MIs to ambient ozone levels, adjusting for covariates. The global models provide an estimated relative MI SER for the state. Realizing that the association in MIs and ozone might change across locations, local models were used to estimate the relative MI SER for each county, again adjusting for covariates. Results differed, depending on whether the spatial support was ignored or accounted for in the models. The opportunities and challenges associated with EPHT analyses are discussed and future directions highlighted. Copyright © 2008 John Wiley & Sons, Ltd.
In situ EDXRF analyses on Renaissance plaquettes and indoor bronzes patina problems and provenance clues
Authors: Bonizzoni Letizia , Galli Anna , Poldi Gianluca
Published: March 2008

The preliminary work for the edition of the complete catalogs of Civic collections of Vicenza (Italy) was an occasion to study by energy dispersive x‐ray fluorescence (EDXRF) about 30 small bronzes and plaquettes of Italian Renaissance. It was necessary to perform in situ analyses directly in the museum without any possibility of sampling or cleaning the objects. We report the results of quantitative analysis on principal and trace elements; moreover, patina problems and the possible clues for raw materials provenance are faced. Copyright © 2008 John Wiley & Sons, Ltd.
Comparison of portable and stationary x‐ray fluorescence spectrometers in the study of ancient metallic artefacts
Authors: Guilherme A. , Cavaco A. , Pessanha S. , Costa M. , Carvalho M. L.
Published: March 2008

The aim of this work is to compare the performance of two x‐ray fluorescence (XRF) spectrometers, a portable one and a non‐portable one, in order to evaluate the advantages and drawbacks of each system. The used spectrometers are not commercial, and in both cases the excitation beams are produced by x‐ray tubes and the detection systems are based on common detectors. The portable system is a 90° geometry between the incident and the emitted beams, and the stationary spectrometer is based on a triaxial geometry with a secondary target. Detection limits are compared for a metallic Cu alloy reference material. A case study for ancient metallic artefacts of Cu‐based alloys, is used to compare the performance of both spectrometers. With the portable spectrometer several tests were carried out using two modes: an ‘unfiltered’ and a ‘filtered’ one in order to evaluate the best peak/background ratio for the studied samples. The obtained results showed significant differences between the two systems, namely, in what concerns peak shaping and trace elements detection. Copyright © 2008 John Wiley & Sons, Ltd.
Study of origin and composition of coatings in a monument built with granitic rocks, by SEM, XRD, XRF and DTA‐TGA
Authors: Sanjurjo Sánchez J. , Vidal Romaní J. R. , Fernández Mosquera D. , Alves C. A.
Published: March 2008

The Casas de Paredes (A Coruña, Spain) is an example of 18th Century neoclassical architecture built with granitic rocks. There are neoformation coatings on the main façade of one of the buildings, producing a visible soiling. Sixteen samples of coatings were collected and studied by SEM (surface and cross‐sections), including analyses by EDS and cross‐sections by x‐ray maps, in order to know their textural and chemical characteristics and to elucidate their origin. Studies by XRD, XRF and DTA/TGA were carried out in most of the samples. These analytical methods have allowed us to recognise up to six types of coatings. Three of them are gypsum‐rich coatings, derived from ancient protection plasters and also, by migration of solutions from lime mortar joints. Air pollution contributes to the blackening of these gypsum coatings and to the formation of black crusts by deposition of fuel combustion particles (Pb‐ and Fe‐rich aggregates, fly‐ash) and other particles (airborne soil particles) on the surface. One of the coatings is a dust crust (with significant amounts of iron, lead and other metals) originated by deposition of atmospheric pollution on ashlar surfaces (without gypsum aggregates). Also, Si‐rich detritic coatings originated by surface alteration of the granitic rock and particle deposition and accretion have been found. The last group is made by coatings originated by deposition (and alteration) of bird excrement. These results could help to define an appropriate cleaning program for the façade, and highlight the relevance of coatings as evidence of pollution agents affecting heritage buildings. Copyright © 2008 John Wiley & Sons, Ltd.