bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid SPE–HPLC determination of the 16 European priority polycyclic aromatic hydrocarbons in olive oils
Authors: Purcaro Giorgia , Moret Sabrina , Conte Lanfranco S.
Published: November 2008

Polycyclic aromatic hydrocarbons (PAHs) are a large class of organic compounds. It has been established that the main source of exposure to these compounds for human beings is through food, particularly fats and oils, due to the lipophilic nature of these polycyclic compounds. The aim of this work was to optimise and validate a method involving SPE and HPLC for rapid determination of the 16 European Union (EU) priority PAHs (required by the Recommendation 2005/108/EC) in vegetable oils. Two spectrofluorometric detectors and a UV‐Visible detector in series were used to identify and quantify the target compounds. Linearity, recoveries, LOD, and LOQ were found to be in agreement with the performance criteria for benzo[a]pyrene (BaP) analysis as required by the Commission Directive 2005/10/EC, and satisfactory for all the compounds of interest, except for cyclopenta[c,d]pyrene, which presented a very low signal in the UV. Optimised chromatographic conditions for the separation of 25 PAHs, comprising both EPA and EU priority PAHs plus benzo[e]pyrene and benzo[b]chrysene, have been also proposed.
Evaluating urbanization, fragmentation and land use/land cover change pattern in Istanbul city, Turkey from 1971 TO 2002
Authors: Çakir G. , Ün C. , Baskent E. Z. , Köse S. , Sivrikaya F. , Keleş S.
Published: November 2008

Spatiotemporal analysis of landscape dynamics is crucial in formulating an appropriate set of actions in landscape management. This paper presents a large scale analysis of the spatiotemporal structure of Istanbul, a highly urbanized city in Turkey, from 1971 to 2002 using forest cover type maps analysed with geographical information systems (GIS) and a spatial statistics programme. The quantitative evidence indicated that increasing population and expanding urbanization caused drastic changes to the temporal and spatial dynamics of land use/land cover pattern in Istanbul. There was a net increase of 5387·3 ha in total forested areas (1·0 per cent) due to mainly reforestation activities even though the population increased three times over a 31‐year period. Increase in number of patches and decrease in mean patch size together demonstrated that the landscape developed into a more fragmented structure that would negatively affect biodiversity and the resilience of the ecosystems. In conclusion, plain increase in forest areas may not always be a favourable situation. The quality, composition and the configuration of forest landscape should also be analysed to present the dynamics of ecosystem in terms of ecological and economical sustainability over a longer time and larger area. Copyright © 2008 John Wiley & Sons, Ltd.
Complete 1H and 119Sn NMR spectral assignment for an asymmetric di[dihydroxotin(IV)] bis‐porphyrin supramolecular host and its corresponding tetraacetato complex
Authors: Brotherhood Peter R. , Luck Ian J. , Crossley Maxwell J.
Published: November 2008

The full 1H and 119Sn NMR spectral assignments for a di[dihydroxotin(IV)] bis‐porphyrin supramolecular host I and for the di[diacetatotin(IV)] complex II are presented. Despite the lack of varied chemical functionality in these molecules, all of their 64 proton environments are non‐equivalent. This is due to the asymmetry afforded by the Tröger's base (methanodiazocine) bridge between the porphyrin and quinoxalinoporphyrin macrocycles. The methanodiazocine bridge imparts chirality and concavity on the host framework and the quinoxalino link to one porphyrin macrocycle results in a negation of C2 symmetry. The anisotropy of the aromatic porphyrin and quinoxalinoporphyrin macrocycles results in good dispersion for all 60 signals of the host framework and for the four ligands bound in the axial positions of the tin(IV) centres. The full assignment of the 1H NMR spectra for these systems was achieved using dqf‐COSY, NOESY, ROESY, 1H‐119Sn HMQC, 1H‐13C HSQC and 1H‐13C HMBC spectroscopy at temperatures that optimised dispersion. The 1H‐119Sn HMQC was particularly useful in this assignment. The 119Sn chemical shift is sensitive to the functionality of the porphyrin and to the nature of the axial ligation, and the 119Sn centre couples to both the ligand protons and the β‐pyrrolic protons. This allows unequivocal identification of the spin systems associated with each metal centre. Copyright © 2008 John Wiley & Sons, Ltd.
Three‐dimensional fundamental solution for transversely isotropic piezothermoelastic material
Authors: Hou P. F. , Leung A. Y. T. , Chen C. P.
Published: November 2008

Fundamental solutions play an important role in electroelastic analyses and numerical methods of piezoelectric material. However, most works available on this topic are on the case of identical temperature. We use the compact mono‐harmonic general solutions of transversely isotropic piezothermoelastic material to construct the three‐dimensional fundamental solution of a steady point heat source in an infinite piezothermoelastic material by four newly introduced mono‐harmonic functions. All components of coupled field are expressed in terms of elementary functions and are convenient to use. Numerical results for cadmium selenide are given graphically by contours. Copyright © 2008 John Wiley & Sons, Ltd.
Depression, perceived stress, and social support among first‐time Chinese mothers and fathers in the postpartum period
Authors: Gao Ling‐ling , Chan Sally Wai‐chi , Mao Qing
Published: November 2008

We compared the prevalence of depression in the postpartum period and its relationship with perceived stress and social support in first‐time mothers and fathers. A cross‐sectional study was conducted in mainland China with a convenience sample of 130 pairs of parents. Measures taken at 6–8 weeks after delivery included the Edinburgh Postnatal Depression Scale, the Perceived Stress Scale, and the Social Support Rating Scale. Eighteen (13.8%) of the mothers and 14 (10.8%) of the fathers were suffering from depression. No signficant differences were found in their prevalence rates. Perceived stress, social support, and partner's depression were significantly associated with depression. These findings suggest counseling, support, and routine screening for depression should be provided to both mothers and fathers. © 2008 Wiley Periodicals, Inc. Res Nurs Health 32:50–58, 2009
Late effects on the urinary bladder in patients treated for cancer in childhood: A report from the Children's Oncology Group
Authors: Ritchey Michael , Ferrer Fernando , Shearer Patricia , Spunt Sheri L.
Published: November 2008

Childhood cancer survivors who have had pelvic or central nervous system surgery or have received alkylator‐containing chemotherapy or pelvic radiotherapy as part of their cancer therapy may experience urinary bladder late effects. This article reviews the medical literature on long‐term bladder complications in survivors of childhood cancer and outlines the Children's Oncology Group Long‐Term Follow‐up (COG LTFU) Guidelines related to bladder function. An overview of the treatment of bladder late effects and recommended counseling for survivors with these complications are presented. Pediatr Blood Cancer 2009;52:439–446. © 2008 Wiley‐Liss, Inc.
Predicting the cure of thermosetting polymers: The isoconversion map
Authors: Ruiz Edu , Billotte C.
Published: November 2008

The modeling of the cure kinetics is widely used to predict the progress of the chemical reaction during processing of thermosetting resins. In this study, a new technique named the “Isoconversion Map” is proposed to predict thermoset curing from a series of differential scanning calorimetry (DSC) analyses. On the basis of the isoconversion methodology, it is possible to devise a model‐free technique to predict resin conversion for a given temperature profile. In this work, the cure kinetics of an epoxy resin has been measured by dynamic DSC tests to construct the proposed “isoconversion map.” The evolution of the resin cure for a given temperature profile has been determined by applying the proposed approach and then compared with the predictions of common cure kinetics models. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
An algorithm to identify antidepressant users with a diagnosis of depression from prescription data
Authors: Gardarsdottir Helga , Egberts Antoine C. G. , van Dijk Liset , Sturkenboom Miriam C. J. M. , Heerdink Eibert R.
Published: November 2008

Purpose

Antidepressants are used for many indications besides depression. This makes investigating depression treatment outcomes in prescription databases problematic when the indication is unknown. The aim of our study is to develop an algorithm to identify antidepressant drug users from prescription data that suffer from depression.

Methods

Data for deriving the algorithm were obtained from the Second Dutch National Survey of General Practice, carried out in 2001 by The Netherlands Institute for Health Services Research (NIVEL), and for validation the Integrated Primary Care Information (IPCI) database was used. Both sets included adults receiving their first antidepressant drug in 2001 (n = 1855 and 3321, respectively). The outcome was a registered diagnosis of depression. Covariates investigated for developing the algorithm were patient and prescribing characteristics, and co‐medication.

Results

The predictive algorithm included age, SSRI prescribed on the index date, prescribed dose, general practitioner as prescriber and the number of antidepressant prescriptions prescribed plus medication for treating acid related disorders, laxatives, cardiac therapy or hypnotics/sedatives prescribed in the 6 months prior to index date. The probability that the algorithm correctly identified an antidepressant drug user as having a depression diagnosis was 79% with a sensitivity of 79.6% and a specificity of 66.9%.

Conclusion

In conclusion, we developed and validated an algorithm that can be used to compose cohorts of patients treated with antidepressants for depression from prescription databases. Copyright © 2008 John Wiley & Sons, Ltd.
Prescribing of pain medication in palliative care. A survey in general practice
Authors: Borgsteede Sander D. , Deliens Luc , Zuurmond Wouter W. A. , Schellevis François G. , Willems Dick L. , Van der Wal Gerrit , van Eijk Jacques Th. M.
Published: November 2008

Purpose

To examine what pain and adjuvant medication is prescribed in palliative care patients at home in The Netherlands.

Methods

In a nationwide, representative, prospective study in general practice in The Netherlands, prescribed medication was registered in 95 general practices with a listed population of 374 070 patients. The GPs identified those who received palliative care in a retrospective survey of the 2169 patients who died within the 1‐year study period. We analysed the analgesics, laxatives and anti‐emetics that were prescribed during the last 3 months of life for these patients.

Results

The response rate of the survey was 74%. 425 patients received palliative care and 73% of them were prescribed pain medication: 55% a non‐opioid analgesic (paracetamol, NSAIDs), 21% a weak opioid (tramadol, codeine), and 51% a strong opioid. Relatively more younger than older patients were prescribed strong opioids, and more cancer than non‐cancer patients were prescribed an analgesic. During the last 3 months of life, the proportion of patients prescribed a non‐opioid or a weak opioid increased gradually. The proportion of patients prescribed a strong opioid increased considerably nearing the patient's death. About one third of the non‐cancer patients were prescribed strong opioids, mostly commencing in the last 2 weeks before death. In 48% of all patients with an opioid prescription, the GP did not prescribe a laxative.

Conclusions

Weak opioids and laxatives are frequently omitted from pain regimens in palliative care at home in The Netherlands. Copyright © 2008 John Wiley & Sons, Ltd.
Structural, electronic, and optical properties of oligoquinolines for light‐emitting diodes
Authors: Li Lei‐Jiao , Feng Ji‐Kang , Ren Ai‐Min
Published: November 2008

The purpose of this work is to provide an in‐depth investigation of the electronic and optical properties of a series of n‐type conjugated oligomers, including 4‐phenyl‐6‐(4‐phenylquinolin‐6‐yl)quinoline (B1), 6,6′‐bis(2,4‐diphenylquinoline) (B1PPQ), 6,6′‐bis(2‐(4‐tert‐butylphenyl)‐4‐phenylquinoline) (BtBPQ), 6,6′‐bis(2‐p‐biphenyl)‐4‐phenylquinoline) (B2PPQ), and 4‐(6‐(2‐(4‐aminophenyl)‐4‐phenylquinolin‐6‐yl)‐4‐phenylquinolin‐2‐yl)benzenamine (BNPPQ). The geometric and electronic structures of the oligomers in the ground state were investigated using density functional theory (DFT) and the ab initio HF, whereas the lowest singlet excited states were optimized with ab initio CIS. To assign the absorption and emission peaks observed in the experiment, we computed the energies of the lowest singlet excited states with time‐dependent (TD) DFT (TD‐DFT). All DFT calculations were performed using the B3LYP functional and the 6‐31G basis set. The results show that the HOMOs, LUMOs, energies gaps, ionization potentials and electron affinities for each molecular are significantly affected by varying the aryl substituents, which favor the hole injection into OLEDs. The absorption and emission spectra exhibit red shifts to some extent [the absorption spectra: 335.85 (B1)< 370.63 (B1PPQ) < 376.77 (BtBPQ)< 388.67 (B2PPQ)< 412.93 nm (BNPPQ); the emission spectra: 391.48 (B1)< 430.11 (B1PPQ)< 435.86 (BtBPQ)< 444.57 (B2PPQ)< 463.28nm (BNPPQ)]. The radiative lifetimes (τ) of each oligomers are calculated as well. Because of introducing the cooperation with the electron donators such as the amidocyanogen in the common 4‐phenyl‐6‐(4‐phenylquinolin‐6‐yl)quinoline core for BNPPQ, which results in improving the hole‐creating ability. Copyright © 2008 John Wiley & Sons, Ltd.
Toward high‐resolution homology modeling of antibody Fv regions and application to antibody–antigen docking
Authors: Sivasubramanian Arvind , Sircar Aroop , Chaudhury Sidhartha , Gray Jeffrey J.
Published: November 2008

High‐resolution homology models are useful in structure‐based protein engineering applications, especially when a crystallographic structure is unavailable. Here, we report the development and implementation of RosettaAntibody, a protocol for homology modeling of antibody variable regions. The protocol combines comparative modeling of canonical complementarity determining region (CDR) loop conformations and de novo loop modeling of CDR H3 conformation with simultaneous optimization of VL‐VH rigid‐body orientation and CDR backbone and side‐chain conformations. The protocol was tested on a benchmark of 54 antibody crystal structures. The median root mean square deviation (rmsd) of the antigen binding pocket comprised of all the CDR residues was 1.5 Å with 80% of the targets having an rmsd lower than 2.0 Å. The median backbone heavy atom global rmsd of the CDR H3 loop prediction was 1.6, 1.9, 2.4, 3.1, and 6.0 Å for very short (4–6 residues), short (7–9), medium (10–11), long (12–14) and very long (17–22) loops, respectively. When the set of ten top‐scoring antibody homology models are used in local ensemble docking to antigen, a moderate‐to‐high accuracy docking prediction was achieved in seven of fifteen targets. This success in computational docking with high‐resolution homology models is encouraging, but challenges still remain in modeling antibody structures for sequences with long H3 loops. This first large‐scale antibody–antigen docking study using homology models reveals the level of “functional accuracy” of these structural models toward protein engineering applications. Proteins 2009; 74:497–514. © 2008 Wiley‐Liss, Inc.
Protective effect of quercetin against ICV colchicine‐induced cognitive dysfunctions and oxidative damage in rats
Authors: Kumar Anil , Sehgal Neha , Kumar Puneet , Padi S. S. V. , Naidu P. S.
Published: November 2008

Intracerebroventricular (i.c.v.) administration of colchicine, a microtubule‐disrupting agent, causes cognitive dysfunction and oxidative stress. The present study was designed to investigate the protective effects of quercetin against colchicine‐induced memory impairment and oxidative damage in rats. An i.c.v. cannula was implanted in the lateral ventricle of male Wistar rats. Colchicine was administered at dose of 15 µg/rat. Morris water maze and plus‐maze performance tests were used to assess memory tasks. Various biochemical parameters such as lipid peroxidation, reduced glutathione, nitrite level, acetylcholinesterase and proteins were also assessed. Central administration of colchicine (15 µg/rat) showed poor retention of memory. Chronic treatment with quercetin (20 and 40 mg/kg, p.o.) twice daily for a period of 25 days beginning 4 days prior to colchicine injection significantly improved the colchicine‐induced cognitive impairment. Biochemical analysis revealed that i.c.v. colchicine injection significantly increased lipid peroxidation, nitrite and depleted reduced glutathione activity in the brains of rats. Chronic administration of quercetin significantly attenuated elevated lipid peroxidation and restored the depleted reduced glutathione, acetylcholinesterase activity and nitrite activity. The results of the present study clearly indicated that quercetin has a neuroprotective effect against colchicine‐induced cognitive dysfunctions and oxidative damage. This article was published online on 3 November 2008. An error was subsequently identified. This notice is included in the online and print version to indicate that both have been corrected. [24 November 2008] Copyright © 2008 John Wiley & Sons, Ltd.
Stable isotopes to discriminate lambs fed herbage or concentrate both obtained from C3 plants
Authors: Moreno‐Rojas Jose M. , Vasta Valentina , Lanza Alfio , Luciano Giuseppe , Ladroue Virginie , Guillou Claude , Priolo Alessandro
Published: November 2008

This study was aimed at determining whether isotopic ratio mass spectrometry (IRMS) enables us to discriminate between lambs fed herbage or concentrate, both obtained from C3 plants, and those fed a concentrate obtained from C4 plants. Thirty‐four Comisana male lambs (age 45 days) were assigned to three feeding treatments. Fourteen lambs were fed vetch (Vicia sativa) ad libitum. Another fourteen lambs received a barley‐based concentrate. The remaining six lambs were fed a maize‐based concentrate. After 60 days of experimental treatment the animals were slaughtered and the wool, perirenal fat and muscle longissimus dorsi were sampled. The δ13C and δ15N values of the muscle, wool and feed were measured by continuous flow elemental analysis (CF‐EA)‐IRMS. The δ13C of the fat was determined likewise. The isotopic composition of the tissues reflected that of the three diets. For the lambs which were fed herbage the muscle δ13C values were higher (P < 0.0005) and δ15N values were lower (P < 0.0005) than those of the lambs receiving concentrates. The δ15N and δ13C values in the muscle and δ13C values in the adipose tissue allowed perfect discrimination between the lambs fed the three different diets. The regression between the δ13C values measured in muscle and in wool of lambs was linear (R2 = 0.99; P < 0.0005). This result shows that δ13C measured in the wool can predict muscle δ13C distribution, suggesting that wool is a valuable matrix for meat authentication. Copyright © 2008 John Wiley & Sons, Ltd.
Stable isotope ratio analysis as a tool to discriminate between rainbow trout (O. mykiss) fed diets based on plant or fish‐meal proteins
Authors: Moreno‐Rojas J. M. , Tulli F. , Messina M. , Tibaldi E. , Guillou C.
Published: November 2008

The use of stable isotope ratio analysis (SIRA) as a rapid analytical tool to characterize and discriminate farmed fish on the basis of the feedstuffs included in the diet formulation is discussed. Two isoproteic (44.8%) and isolipidic (19.6%) extruded diets were formulated: a fish‐meal‐based diet (FM diet), containing fish meal as the sole protein source; a plant‐protein‐based diet (PP diet), where pea protein concentrate and wheat gluten meal replaced 80% of fish meal protein. The diets were fed to eight groups of rainbow trout (initial body weight: 106.6g) for 103 days in two daily meals under controlled rearing conditions. Growth performance (final body weight: 318.5 g; specific growth rate: 1.06%) and feed‐to‐gain ratio (0.79) were not affected by the dietary treatment. The differences in isotopic values of the two diets were clearly reflected in the different carbon and nitrogen isotopic values in rainbow trout fillets. The δ13C and δ15N values of muscle of farmed rainbow trout showed differences between farmed fish fed a fish‐protein‐based diet (−20.47 ± 0.34 and 12.38 ± 0.57 for δ13C and δ15N, respectively) and those fed a plant‐protein‐based diet (−23.96 ± 0.38 and 7.15 ± 0.51 for δ13C and δ15N, respectively). The results suggest that SIRA provides a robust and verifiable analytical tool to discriminate between fish fed on a plant or a fish protein diet. Copyright © 2008 John Wiley & Sons, Ltd.
Characterisation of varnishes used in violins by pyrolysis‐gas chromatography/mass spectrometry
Authors: Chiavari Giuseppe , Montalbani Simona , Otero Vanessa
Published: November 2008

The correct characterisation and a detailed knowledge of the materials originally used in violin varnishes, like natural resins, is crucial for the conservation in museums and for a suitable restoration technique. The study presented here reports on the potential of pyrolysis (Py) coupled with gas chromatography (GC) and mass spectrometry (MS) for the identification of chemical markers of each resin; this tecnique is very sensitive and selective, it needs a small quantity of sample and does not require chemical treatments. To improve the chromatographic behaviour of polar compounds the derivatising agent tetramethylammonium hydroxide (TMAH) in combination with pyrolysis has been used, in the so‐called TMAH thermochemolysis or thermally assisted hydrolysis and methylation (THM), or more simply pyrolysis‐methylation. The natural resins studied were colophony, sandarac, manila copal, elemi, amber and benzoin, mainly composed of terpenic compounds, with the exception of the latter, composed of aromatic compounds. Many compounds were identified; in particular, methyl esters of resinous acids that, individually or in a group, can be used as chemical markers. However, through this technique it was not possible to distinguish between the sandarac and manila copal resins because their chromatographic behaviour is very similar. Finally, the procedure applied has been employed in the characterisation of original varnish samples. Copyright © 2008 John Wiley & Sons, Ltd.
On‐line preconcentration and quantitative analysis of peptide hormone of brain and intestine using on‐column transient isotachophoresis coupled with capillary electrophoresis/electrospray ionization mass spectrometry
Authors: Xia Shifei , Zhang Lan , Qiu Bin , Lu Minghua , Chi Yuwu , Chen Guonan
Published: November 2008

A new approach was described to achieve very sensitive analysis of peptide hormone of brain and intestine by capillary electrophoresis coupled with a transient isotachophoresis (tITP) preconcentration method. The system used was electrospray ionization mass spectrometry (ESI‐MS) as detector and equipped with a sheath flow configuration. The effects of sample matrix, pH and concentration of leading electrolyte (LE), sample injection time, and ESI‐MS instrumental parameters on the efficiency of the sample stacking were investigated in detail. Under the optimized conditions, lower than micromole (0.01 µM) concentrations of the peptides were easily detected. Compared to traditional hydrodynamic injection methods, about 40–230‐fold increase in detection sensitivity was obtained by this technique. A distinguishing feature of the described approach is that the background electrolyte can serve as terminating electrolyte (TE), which simplifies the process of the experiments. The method was further evaluated by the analysis of low concentration active peptide mixtures spiked in hypothalamus tissue of the rat. Copyright © 2008 John Wiley & Sons, Ltd.
Matrix‐assisted laser desorption/ionization mass spectrometry screening for pseudouridine in mixtures of small RNAs by chemical derivatization, RNase digestion and signature products
Authors: Durairaj Anita , Limbach Patrick A.
Published: November 2008

We have developed a method to screen for pseudouridines in complex mixtures of small RNAs using matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS). First, the unfractionated crude mixture of tRNAs is digested to completion with an endoribonuclease, such as RNase T1, and the digestion products are examined using MALDI‐MS. Individual RNAs are identified by their signature digestion products, which arise through the detection of unique mass values after nuclease digestion. Next, the endonuclease digest is derivatized using N‐cyclohexyl‐N′‐(2‐morpholinoethyl)carbodiimide metho‐p‐toluenesulfonate (CMCT), which selectively modifies all pseudouridine, thiouridine and 2‐methylthio‐6‐isopentenyladenosine nucleosides. MALDI‐MS determination of the CMCT‐derivatized endonuclease digest reveals the presence of pseudouridine through a 252 Da mass increase over the underivatized digest. Proof‐of‐concept experiments were conducted using a mixture of Escherichia coli transfer RNAs and endoribonucleases T1 and A. More than 80% of the expected pseudouridines from this mixture were detected using this screening approach, even on an unfractionated sample of tRNAs. This approach should be particularly useful in the identification of putative pseudouridine synthases through detection of their target RNAs and can provide insight into specific small RNAs that may contain pseudouridine. Copyright © 2008 John Wiley & Sons, Ltd.
Identification of the rapamycin‐sensitive phosphorylation sites within the Ser/Thr‐rich domain of the yeast Npr1 protein kinase
Authors: Gander Stefan , Bonenfant Debora , Altermatt Patrick , Martin Dietmar E. , Hauri Simon , Moes Suzette , Hall Michael N. , Jenoe Paul
Published: November 2008

The Saccharomyces cerevisae nitrogen permease reactivator Npr1 is a hyperphosphorylated protein that belongs to a fungus‐specific family of Ser/Thr protein kinases dedicated to the regulation of plasma membrane transporters. Its activity is regulated by the TOR (target of rapamycin) signalling pathway. Inhibition of the TOR proteins by treating yeast cells with the immunosuppressant drug rapamycin promotes rapid dephosphorylation of Npr1. To identify the rapamycin‐sensitive phosphorylation sites in yeast Npr1, glutathione‐S‐transferase (GST)‐tagged Npr1 was isolated from untreated or rapamycin‐treated cells, and analyzed by mass spectrometry. Here, we report for the first time 22 phosphorylation sites that are clustered in two regions of the N‐terminal serine‐rich domain. All phosphorylation sites, except two, were found to be rapamycin‐sensitive. Some phosphorylation sites are contained in motifs that closely resemble those in mammalian S6K (serines followed by a tyrosine or a phenylalanine) and 4E‐BP1 (serines followed by a proline). Other sites, such as serines followed by Ala, Asn, Gln, His, Ile, Leu, or Val, appear to define new motifs. Thus, TOR controls an unusually broad array of phosphorylation sites in Npr1. In addition to phosphorylation by upstream kinases, Npr1 undergoes autophosphorylation that was mapped to three distinct serines in the N‐terminal domain of which Ser257 appears to be the main autophosphorylation site. Site‐directed mutagenesis confirmed the mass spectral assignments of the autophosphorylation sites and shows that Ser257 is specifically involved in forming an in vitro substrate‐binding site. Copyright © 2008 John Wiley & Sons, Ltd.
Characterization of the DNA adducts induced by aristolochic acids in oligonucleotides by electrospray ionization tandem mass spectrometry
Authors: Chan Wan , Yue Hao , Wong Ricky N. S. , Cai Zongwei
Published: November 2008

Metabolic activation of carcinogenic aristolochic acids (AA) produces reactive aristolactam‐nitrenium ion intermediates. Electrophilic attack of the aristolactam‐nitrenium ion via its C7 position to the exocyclic amino group in the purine bases leads to the formation of DNA adducts. DNA‐binding assays have demonstrated that carcinogens show site‐ and sequence‐specificity and the biological consequence is defined by the nature of binding as well as their position in the genome. In this study, electrospray ionization tandem mass spectrometry was applied for the identification and position mapping of DNA adducts in oligonucleotides (ODNs). The developed method was successfully applied for the analysis of unmodified and AA‐modified ODNs (5′‐TTTATT‐3′, 5′‐TTTGTT‐3′ and 5′‐TACATGTGT‐3′). The observation of the modified bases (modified adenine and guanine) together with the complementary product ions ([an‐B*n]−, w−) from the cleavage of the 3′ CO bond adjacent to the modified base in MS/MS analyses readily enabled the identification of the AA‐binding site in ODNs. Copyright © 2008 John Wiley & Sons, Ltd.
Using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry to rapidly screen for albuminuria
Authors: Shiea Jentaie , Cho Yi‐Tzu , Lin Yen‐Hsiu , Chang Chin‐Wen , Lo Li‐Hua , Lee Yi‐Chern , Ke Hung‐Lung , Wu Wen‐Jeng , Wu Deng‐Chyang
Published: November 2008

Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) is used as an alternative method for the rapid diagnosis of albuminuria. This technique requires no further sample pretreatment than simply mixing the urine sample with a MALDI matrix and drying under ambient conditions. The resulting MALDI mass spectra reveal albumin ions having charges ranging from +1 to +5. The detection of albumin is possible using any of the three most common MALDI matrices – sinapinic acid (SA), 2,5‐dihydroxybenzoic acid (2,5‐DHB), or 4‐hydroxy‐α‐cyanocinnamic acid (α‐CHC). Using this analytical approach, the limit of detection for albumin in urine is 10−6 M, approximately 5 to 10 times lower than that detectable through conventional chemical testing. Copyright © 2008 John Wiley & Sons, Ltd.
Titanium dioxide anatase as matrix for matrix‐assisted laser desorption/ionization analysis of small molecules
Authors: Castro Ana L. , Madeira Paulo J. Amorim , Nunes Manuel R. , Costa Fernanda M. , Florêncio M. Helena
Published: November 2008

The use of inorganic species as assisting materials in matrix‐assisted laser desorption/ionization (MALDI) analysis is an alternative approach to avoid interfering matrix ions in the low‐mass region of the mass spectra. Reports of the application of inorganic species as matrices in MALDI analysis of small molecules are, however, scarce. Nevertheless, titanium dioxide (TiO2) powder has been reported to be a promising matrix medium. In this study we further explore the use of TiO2 as a matrix for the MALDI analysis of low molecular weight compounds. We present results showing that nanosized TiO2 anatase and TiO2 rutile perform better as MALDI matrices than a commercial TiO2 anatase/rutile mixture. Moreover, when using nanosized TiO2 anatase as a matrix, high‐quality mass spectra can be obtained with strong analyte signals and weak or non‐existing matrix interference ions. Furthermore, our results show that the phase type plays an important role in the application of TiO2 as a MALDI matrix. Copyright © 2008 John Wiley & Sons, Ltd.
On‐line coupling of liquid chromatography at critical conditions with electrospray ionization tandem mass spectrometry for the characterization of a nitroxide‐mediated poly(ethylene oxide)/polystyrene block copolymer
Authors: Girod Marion , Phan Trang N. T. , Charles Laurence
Published: November 2008

Coupling of liquid chromatography at critical conditions (LCCC) with on‐line mass spectrometry (MS) detection was implemented via an electrospray ionization (ESI) interface, using a mobile phase containing the cationizing agent. Critical conditions established for poly(ethylene oxide) were used to characterize a poly(ethylene oxide)/polystyrene block copolymer (PEO‐b‐PS) in both MS and MS/MS modes. As co‐oligomer molecules were successfully separated according to the PS block size, structural information could be reached from simplified MS spectra. The microstructure of this copolymer, synthesized by nitroxide‐mediated polymerization, could further be unambiguously characterized in LCCC/ESI‐MS/MS experiments since the PS block size could be reached by both the co‐oligomer chromatographic behavior and its MS/MS pattern. Copyright © 2008 John Wiley & Sons, Ltd.
Precursor ion scan profiles of acylcarnitines by atmospheric pressure thermal desorption chemical ionization tandem mass spectrometry
Authors: Paglia Giuseppe , D'Apolito Oceania , Corso Gaetano
Published: November 2008

The fatty acyl esters of L‐carnitine (acylcarnitines) are useful biomarkers for the diagnosis of some inborn errors of metabolism analyzed by liquid chromatography/tandem mass spectrometry. In this study the acylcarnitines were analyzed by atmospheric pressure thermal desorption chemical ionization using a commercial tandem mass spectrometer (APTDCI‐MS/MS). The method is based on the precursor ion scan mode determination of underivatized acylcarnitines desorbed from samples by a hot desolvation gas flow and ionized by a corona pin discharge. During desorption/ionization step the temperature induces the degradation of acylcarnitines; nevertheless, the common fragment to all acylcarnitines [MH–59]+ is useful for analyzing their profile. APTDCI parameters, including angle of collection and incidence, gas flows and temperatures, were optimized for acylcarnitines. The experiments were performed drying 2 µL of an equimolar mixture of acylcarnitine standards on a glass slide. The specificity was evaluated by comparing product ion spectra and the precursor ion spectra of 85 m/z of acylcarnitines obtained by the APTDCI method and by electrospray ionization flow injection analysis (ESI‐FIA). The method was also employed to analyze acylcarnitines extracted from a pathological dried blood spot and a control. The method enables analysis of biological samples and recognition of some acylcarnitines that are diagnostic markers of inherited metabolic diseases. The intrinsic high‐throughput analysis of the ambient desorption ionization methods offers a new opportunity either for its potential application in clinical chemistry and for the expanded screening of some inborn errors of metabolism. Copyright © 2008 John Wiley & Sons, Ltd.
Application of gas chromatography/tandem quadrupole mass spectrometry to the multi‐residue analysis of pesticides in green leafy vegetables
Authors: Walorczyk Stanisław
Published: November 2008

A new, sensitive and specific method has been developed for the simultaneous determination of 129 pesticides in lettuce and other green leafy vegetables. The samples were extracted with acetonitrile and co‐extractives such as fatty acids and pigments were removed using dispersive solid‐phase extraction (dispersive‐SPE) with primary secondary amine (PSA) and graphitized carbon black (GCB). All pesticides were analyzed in a single injection gas chromatography/tandem quadrupole mass spectrometry (GC/MS/MS) acquisition method. Two multiple reaction monitoring (MRM) transitions of precursor ions fragmenting into product ions were recorded for the targeted pesticides, thus fulfilling the EU identification points system criteria for the identification of contaminants (2002/657/EC). Calibration curves were determined using matrix‐matched standards, and exhibited excellent linearity at two orders of magnitude from 0.005 to 0.5 mg/kg for almost all the pesticides studied (R2 ≥ 0.99). The analytical performance was demonstrated by the analysis of lettuce samples spiked at five concentration levels ranging from 0.005 to 0.5 mg/kg for each pesticide. The recovery and repeatability results satisfied SANCO/2007/3131 criteria (i.e. average recoveries were in the range 70–120% with RSDs ≤20%) for 114 of the 129 pesticides at the 0.005 mg/kg spiking level, and for almost all pesticides at the higher spiking levels. The methodology was applied successfully to identify and quantify pesticide residues in leafy vegetable samples such as lettuce, cabbage and leek. Copyright © 2008 John Wiley & Sons, Ltd.
Silver complexation and tandem mass spectrometry for differentiation of triterpenoid saponins from the roots of Pulsatilla chinensis (Bunge) Regel
Authors: Cheng Lin , Zhang Min , Zhang Peng , Song Zhihang , Ma Zhongjun , Qu Haibin
Published: November 2008

For detection and differentiation of two types of triterpenoid saponins based on different aglycons of the lupane and oleanane skeleton from the roots of Pulsatilla chinensis (Bunge) Regel, the silver ion was introduced and electrospray ionization multi‐stage tandem mass spectrometry was applied to analyze eleven triterpenoid saponin silver complexes. The quasi‐molecular ion [M+Ag]+ was observed in the full‐scan MS spectra of all the silver complexes. The MS2 data of the [M+Ag]+ ion provided structural information on the sugar sequence of the oligosaccharide chains and the aglycon of the saponins. There are two patterns in the cleavage pathway of oleanane‐type saponins. One is elimination of the sugar chain and subsequent loss of the carboxylic group which is the same as the cleavage of lupine‐type saponins. The other is loss of the distinguishing ions at m/z 72 and 28 (C2H4) followed by loss of the carboxylic group. Diagnostic fragmentation pathways of the silver complexes of the saponins allow successful identification of the two types of saponins from the roots of Pulsatilla chinensis (Bunge) Regel. Copyright © 2008 John Wiley & Sons, Ltd.
Negative ion ‘chip‐based’ nanospray tandem mass spectrometry for the analysis of flavonoids in glandular trichomes of Lychnophora ericoides Mart. (Asteraceae)
Authors: Gobbo‐Neto Leonardo , Gates Paul J. , Lopes Norberto P.
Published: November 2008

This paper reports a method for the analysis of secondary metabolites stored in glandular trichomes, employing negative ion ‘chip‐based’ nanospray tandem mass spectrometry. The analyses of glandular trichomes from Lychnophora ericoides, a plant endemic to the Brazilian ‘cerrado’ and used in traditional medicine as an anti‐inflammatory and analgesic agent, led to the identification of five flavonoids (chrysin, pinocembrin, pinostrobin, pinobanksin and 3‐O‐acetylpinobanksin) by direct infusion of the extracts of glandular trichomes into the nanospray ionisation source. All the flavonoids have no oxidation at ring B, which resulted in a modification of the fragmentation pathways compared with that of the oxidised 3,4‐dihydroflavonoids already described in the literature. The absence of the anti‐inflammatory and antioxidant di‐C‐glucosylflavone vicenin‐2, or any other flavonoid glycosides, in the glandular trichomes was also demonstrated. The use of the ‘chip‐based’ nanospray QqTOF apparatus is a new fast and useful tool for the identification of secondary metabolites stored in the glandular trichomes, which can be useful for chemotaxonomic studies based on metabolites from glandular trichomes. Copyright © 2008 John Wiley & Sons, Ltd.
Characterization of metabolites of meisoindigo in male and female rat kidney microsomes by high‐performance liquid chromatography coupled with positive electrospray ionization tandem mass spectrometry
Authors: Huang Meng , Choo Lip‐Wee , Ho Paul C.
Published: November 2008

Meisoindigo has been effectively applied for the treatment of chronic myelogenous leukemia (CML). Although the metabolic profile of meisoindigo has been studied in liver, information relevant to extrahepatic metabolism of meisoindigo is absent in kidney so far. In this study, the metabolism of meisoindigo in rat kidney microsomes was qualitatively and quantitatively investigated by liquid chromatography/tandem mass spectrometry (LC/MS/MS), in terms of metabolite identification, metabolic stability, metabolite formation and gender effect. The metabolic profiling was accomplished by integration of multiple reaction monitoring (MRM) with conventional full MS scan followed by MS/MS methodology. The majorin vitrometabolites of meisoindigo in rat kidney microsomes were identified as stereoselective 3,3′ double‐bond reduced meisoindigo, whereas the minor metabolites were regioselective phenyl monohydroxylmeisoindigo. An LC/MS/MS method for quantification of meisoindigo in rat kidney microsomes was also developed and validated. The calculatedin vitrohalf‐life (t1/2) values of meisoindigo in male and female rat kidney microsomes were 107.8 ± 17.0 min and 130.0 ± 12.9 min, respectively. There were no statistically significant differences between different genders in the metabolic stability profiles of meisoindigo. The reductive metabolite‐formation profiles of meisoindigo in male and female rat kidney microsomes were plotted semi‐quantitatively as well. The information regardingin vitrorenal metabolism of meisoindigo provided a better understanding of the role of the kidney in the disposition of meisoindigo. Copyright © 2008 John Wiley & Sons, Ltd.
A possible ethanol‐catalyzed rearrangement of vitamin K1 detected by gas chromatography/mass spectrometry
Authors: Osman Abdimajid , Hannestad Ulf
Published: November 2008

We studied vitamin K1(20), vitamin K1(25), and vitamin K1 epoxide in n‐hexane and ethanol solutions by gas chromatography/mass spectrometry (GC/MS) utilizing a DB‐5 MS fused‐silica capillary column. In ethanol solutions of K1, we observed an extra peak eluting from the GC column with somewhat longer retention time than K1(20). A similar peak following K1(25) was also found. These peaks were not found in n‐hexane solutions of K1. A close examination of the mass spectra of these peaks indicated that they were vitamin K1 variants containing a base peak at m/z 225 characteristic of the methylnaphthoquinone ring with a four‐carbon side chain. In addition, they contained the molecular ions of K1(20) and K1(25), respectively. We conclude that K1(20) and K1(25), but not K1 epoxide, might undergo rearrangements in ethanol involving an intramolecular proton transfer and a shift of the β,γ‐double bond on the phytyl side chain toward the ring. The conjugation of the phytyl double bond with the quinone ring is probably the driving force of the rearrangement. We emphasize, however, that our conclusion is based only on mass spectral analysis and would require further investigation by other spectroscopic methods. Copyright © 2008 John Wiley & Sons, Ltd.
Accelerator mass spectrometry of small biological samples
Authors: Salehpour Mehran , Forsgard Niklas , Possnert Göran
Published: November 2008

Accelerator mass spectrometry (AMS) is an ultra‐sensitive technique for isotopic ratio measurements. In the biomedical field, AMS can be used to measure femtomolar concentrations of labeled drugs in body fluids, with direct applications in early drug development such as Microdosing. Likewise, the regenerative properties of cells which are of fundamental significance in stem‐cell research can be determined with an accuracy of a few years by AMS analysis of human DNA. However, AMS nominally requires about 1 mg of carbon per sample which is not always available when dealing with specific body substances such as localized, organ‐specific DNA samples. Consequently, it is of analytical interest to develop methods for the routine analysis of small samples in the range of a few tens of µg. We have used a 5 MV Pelletron tandem accelerator to study small biological samples using AMS. Different methods are presented and compared. A 12C‐carrier sample preparation method is described which is potentially more sensitive and less susceptible to contamination than the standard procedures. Copyright © 2008 John Wiley & Sons, Ltd.
Evaluation method for linking methamphetamine seizures using stable carbon and nitrogen isotopic compositions: a complementary study with impurity profiling
Authors: Iwata Yuko T. , Kuwayama Kenji , Tsujikawa Kenji , Miyaguchi Hajime , Kanamori Tatsuyuki , Inoue Hiroyuki
Published: November 2008

Drug profiling, extraction of physical and/or chemical profiles from abused drug samples, is useful for inferring and characterizing links between samples originating from the same and different seizures, and supports drug crime investigations. We describe an evaluation method for linking methamphetamine (MA) seizures using stable carbon and nitrogen isotopic compositions concurrently with gas chromatographic impurity profiling, which is one of the major methods of drug profiling. Several sets of MA seized in Japan, whose investigative information indicated linkages, were analyzed. The impurity profile of each set of seizures was quite similar and hierarchical cluster analysis showed a sample classification that was relatively consistent with the investigative information. The stable carbon and nitrogen isotopic compositions of the MA seizures varied between −29.40 and −24.90 (δ13C) and −2.29 and 5.94 (δ15N), respectively. In the δ13C–δ15N graph, MA seizures were classified into seven groups, probably reflecting different origins. The size of the cluster in the isotopic‐composition graph was determined by pooled standard deviations (sp), the pooled estimates of measurement uncertainty. The sizes of the clusters were less than 6sp and the linkages between the MA seizures from the isotopic compositions were consistent with the impurity profiling and investigative information. The results showed that complementary use of stable‐isotopic compositions with impurity profiling provides useful information for evaluating the links between seizures. Copyright © 2008 John Wiley & Sons, Ltd.
Collisionally induced fragmentation of [M–H]− species of resveratrol and piceatannol investigated by deuterium labelling and accurate mass measurements
Authors: Stella Laura , De Rosso Mirko , Panighel Annarita , Vedova Antonio Dalla , Flamini Riccardo , Traldi Pietro
Published: November 2008

Resveratrol (3,5,4′‐trihydroxystilbene) and piceatannol (3,4,3′,5′‐tetrahydroxy‐trans‐stilbene) are phytoalexins present in red grapes and wines. In vitro studies have revealed that piceatannol blocks LMP2A, a viral protein‐tyrosine kinase implicated in leukemia, non‐Hodgkin's lymphoma and other diseases associated with the Epstein‐Barr virus, and has an antimelanoma effect on human melanoma cells. Resveratrol has several beneficial effects on human health, such as anticancer, cardioprotection, antioxidant, inhibition of platelet aggregation and anti‐inflammatory activity. In this investigation, the collisional behaviour of deprotonated resveratrol and piceatannol obtained under electrospray conditions is described. The mechanisms involved in the fragmentation pattern of [M–H]− species of the two compounds were investigated by performing MSn experiments, deuterium labelling and accurate mass measurements. Copyright © 2008 John Wiley & Sons, Ltd.