bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of solvent and electrospray mass spectrometer parameters on the charge state distribution of peptides – a case study using liquid chromatography/mass spectrometry method development for beta‐endorphin assay
Authors: Hewavitharana A. K. , Herath H. M. D. R. , Shaw P. N. , Cabot P. J. , Kebarle P. 
Published: November 2010

AbstractBeta‐endorphin was used as a model peptide to study the effect of solvent and electrospray mass spectrometer parameters in the optimisation of an assay method for multiply charged compounds using liquid chromatography/mass spectrometry (LC/MS). Unlike with singly charged compounds, the charge state distribution has a significant impact in the method development of multiply charged compounds such as peptides. Using a 50% acetonitrile/water solvent mixture, we found that the ion spray voltage had no influence on the charge state distribution. However, increasing declustering potential led to deprotonation of the higher charge states of the peptide thus causing a shift to lower charge states. The mechanism leading to the deprotonation was examined. It was concluded that the deprotonation is due to endoergic proton transfer from the peptide to solvent molecules clustered to the peptide that occurs in the declustering region. The extent of deprotonation increases with increasing proton affinity of the molecules of the non‐aqueous solvent component used. Thus, if desired, deprotonation can be avoided by selecting a low proton affinity solvent such as methanol. The focusing potential was also found to have a great influence on the charge state distribution observed. The results of this study enabled us to select the optimum ion to be used in single ion/reaction monitoring mode. They also provided the most favourable parameter values to be used in the method to obtain the best sensitivity for the ion of choice. The results demonstrate the importance of considering the charge state distribution in the optimisation of electrospray LC/MS methods for multiply charged compounds. Copyright © 2010 John Wiley & Sons, Ltd.
Determination of polymer electrolyte membrane (PEM) degradation products in fuel cell water using electrospray ionization tandem mass spectrometry
Authors: Zedda Marco , Tuerk Jochen , Peil Stefan , Schmidt Torsten C. 
Published: November 2010

AbstractWithin the scope of research of membrane degradation phenomena during fuel cell operation a reliable analytical procedure for the extraction, detection and quantification of possible membrane oxidation products has been developed. These oxidation products originate from the attack of hydroxyl or peroxyl radicals on the membrane polymer. Such radicals are formed in situ (during fuel cell operation) or ex situ (Fenton test as oxidative stress simulation). The analysis of membrane oxidation products was carried out by electrospray ionization tandem mass spectrometry. Five potential membrane oxidation products (4‐hydroxybenzoic acid (4‐HBA), 4‐hydroxybenzaldehyde (4‐HBAD), 4,4‐biphenol (4,4‐BP), 4‐hydroxybenzenesulfonate (4‐HBS), and 4,4‐sulfonylbiphenol (4,4‐SBP)) were selected based on the molecular structure of the sulfonated polyarylether membrane used. In conjunction with the development of a multiple reaction monitoring (MRM) method, the ionization and fragmentation of the selected compounds were investigated. For 4,4‐BP a molecular ion (M+•) was observed in the positive ionization mode and used for MRM method development. Reproducible extraction of the model compounds was achieved using a mixed‐mode sorbent material with both weak anion‐exchange and reversed‐phase retention properties. By using the developed analytical procedure, the identities of two membrane degradation products (4‐HBA and 4‐HBAD) were determined in situ and ex situ. In addition to the investigation of membrane degradation phenomena, the combination of extraction on a mixed‐mode sorbent material and tandem mass spectrometric detection is attractive for the analysis of aromatic sulfonic acids, phenolic acids and phenols. Copyright © 2010 John Wiley & Sons, Ltd.
Concentration effects on laser‐based δ18O and δ2H measurements and implications for the calibration of vapour measurements with liquid standards
Authors: Schmidt Markus , Maseyk Kadmiel , Lett Céline , Biron Philippe , Richard Patricia , Bariac Thierry , Seibt Ulli 
Published: November 2010

AbstractRecently available isotope ratio infrared spectroscopy can directly measure the isotopic composition of atmospheric water vapour (δ18O, δ2H), overcoming one of the main limitations of isotope ratio mass spectrometry (IRMS) methods. Calibrating these gas‐phase instruments requires the vapourisation of liquid standards since primary standards in principle are liquids. Here we test the viability of calibrating a wavelength‐scanned cavity ring‐down spectroscopy (CRDS) instrument with vapourised liquid standards. We also quantify the dependency of the measured isotope values on the water concentration for a range of isotopic compositions. In both liquid and vapour samples, we found an increase in δ18O and δ2H with water vapour concentration. For δ18O, the slope of this increase was similar for liquid and vapour, with a slight positive relationship with sample δ‐value. For δ2H, we found diverging patterns for liquid and vapour samples, with no dependence on δ‐value for vapour, but a decreasing slope for liquid samples. We also quantified tubing memory effects to step changes in isotopic composition, avoiding concurrent changes in the water vapour concentration. Dekabon tubing exhibited much stronger, concentration‐dependent, memory effects for δ2H than stainless steel or perfluoroalkoxy (PFA) tubing. Direct vapour measurements with CRDS in a controlled experimental chamber agreed well with results obtained from vapour simultaneously collected in cold traps analysed by CRDS and IRMS. We conclude that vapour measurements can be calibrated reliably with liquid standards. We demonstrate how to take the concentration dependencies of the δ‐values into account. Copyright © 2010 John Wiley & Sons, Ltd.
Variations in science teaching modalities and students' pedagogic subject positioning through the discourse register and language code
Authors: Maeng Seungho , Kim Chan‐Jong 
Published: November 2010

AbstractThis study investigated the modalities of science teaching practice and students' pedagogic subject positioning through the linguistic features of science classroom discourse and the discursive interaction. For this purpose, this study sought to develop a methodology for classroom discourse analysis, the TMARC (Triangular Model of Analyzing discourse Register and language Code). Applied to a middle school science classroom, the TMARC revealed that there were six types of teaching modalities during the classroom practices in spite of the teacher's predominant didactic teaching and that there existed the diverse variation types of the teaching modalities according to a temporal order. In addition, we found four types of pedagogic subject positioning through the application of TMARC. We also argued that the pedagogic subject positioning of a successful science learner was implemented in the discourse language codes of personal collaborative open discourse, positional collaborated open discourse, and personal collaborative controlled discourse. Each of these related to the science teaching modality in which student centeredness was emphasized. Thus, this study suggests that a science teacher's competency related to managing classroom discourse can control students' pedagogic subject position and, by extension, contribute to students' science learning. © 2010 Wiley Periodicals, Inc.Sci Ed95:431–457, 2011
Transient and steady‐state magnetic fields induce increased fluorodeoxyglucose uptake in the rat hindbrain
Authors: Frilot Clifton , Carrubba Simona , Marino Andrew A. 
Published: November 2010

AbstractWe inquired into the biophysical basis of the ability of weak electromagnetic fields (EMFs) to trigger onset and offset evoked potentials, and to produce steady‐state changes in the electroencephalogram (EEG). Rats were exposed to a 2.5‐G, 60‐Hz magnetic field and the neuroanatomical region of glucose activation associated with the effect of the field on the EEG was identified by positron emission tomography (PET) using fluorodeoxyglucose (FDG). Paired emission scans from the same animal with and without field treatment were differenced and averaged, and t values of the brain voxels computed using the pooled standard deviation were compared with a calculated critical t value to identify the field‐activated voxels. Increased glucose utilization occurred in hindbrain voxels when the field was applied orthogonally to the sagittal plane, but not when the angle between the field and the sagittal plane varied randomly. Distinct FDG activation effects were observed in response to transient (both onset and offset) and steady‐state magnetic stimuli. Observations of increased glucose utilization induced by magnetic stimuli and its dependence on the direction of the field suggested that signal transduction was mediated by a force detector and that the process and/or early posttransduction processing occurred in the hindbrain. Synapse, 2011. © 2010 Wiley‐Liss, Inc.
The efficacy of n-3 fatty acids DHA and EPA (fish oil) for perinatal depression
Authors: Jans Linda A. W. , Giltay Erik J. , Willem Van der Does A. J. 
Published: November 2010

Depressive symptoms are common during pregnancy and the post-partum period. Although essential n-3 PUFA may have beneficial effects on depression, it remains unclear whether they are also effective for perinatal depression. The purpose of the present study was to assess the efficacy of n-3 supplementation for perinatal depression, by performing a meta-analysis on currently available data. After a thorough literature search, we included seven randomised controlled trials in the meta-analysis, all with EPA and/or DHA supplementation. Most studies were judged to be of low-to-moderate quality, mainly due to small sample sizes and failure to adhere to Consolidated Standards of Reporting Trials guidelines. Some studies were not primarily designed to address perinatal depression. A total of 309 women on n-3 fatty acid supplementation were compared with 303 women on placebo treatment. n-3 Supplementation was not found to be significantly more effective than placebo at post-treatment with a pooled effect size (Hedges's g) of − 0·03 (95 % CI − 0·18, 0·13; P = 0·76) using a fixed-effects model. Heterogeneity was low-to-moderate (I2 = 30 %). In a subgroup analysis of three small studies of pregnant women with major depression, there was some indication of effectiveness (effect size 0·17; 95 % CI − 0·21, 0·55). In conclusion, the question of whether EPA and DHA administration is effective in the prevention or treatment of perinatal depression cannot be answered yet. Future research should focus on women who are clinically depressed (or at risk). The quality of research in this area needs to improve.
The antioxidant role ofSideritis caesareainfusion against TCA toxicity in rats
Authors: Celik Ismail , Kaya Mehmet Salih 
Published: November 2010

Sideritis caesarea(SC) Duman, Aytac&Baser is a member of the Lamiaceae family. The present study was designed to investigate the antioxidant properties of the aerial parts of island green tea SC against TCA effects in rats. Biomarkers selected for monitoring antioxidant capacity were the activities of glutathione reductase (GR), superoxide dismutase (SOD), glutathione-S-transferase, catalase (CAT), GSH level and malondialdehyde (MDA) content in various organs of rats. Three experimental groups, A (untreated = control), B (only TCA-treated) and C (TCA+SC-treated), were studied. At the end of the 50 d experiment, the MDA content in tissues increased significantly in group B, whereas no significant changes were observed in group C as compared with that of the control group. Antioxidant enzyme activities such as SOD and CAT increased significantly in the brain, liver and kidneys of group B but decreased significantly in group C as compared with group B. The GSH level and GR activity increased significantly in the brain and liver of group C as compared with the control and TCA-exposed rats. Hence, the study reveals that the constituents present in SC impart protection against chemical-induced oxidative injury that may result in the development of cancer.
Curcumin induces paraoxonase 1 in cultured hepatocytes in vitro but not in mouse liver in vivo
Authors: Schrader Charlotte , Schiborr Christina , Frank Jan , Rimbach Gerald 
Published: November 2010

Paraoxonase 1 (PON1) is an enzyme that is mainly synthesised in the liver and protects LDL from oxidation, thereby exhibiting antiatherogenic properties. Using a luciferase reporter gene assay, we tested curcumin for its ability to induce PON1 in Huh7 hepatocytes in culture. Curcumin ( ≥ 10 μmol/l) dose-dependently induced PON1 transactivation in Huh7 cells. However, dietary supplementation of female B6C3F1 mice with curcumin (500 mg/kg diet) for 2 weeks did not increase the hepatic PON1 mRNA and protein levels. No curcumin was detectable in the plasma of the 12 h fasted mice. In conclusion, curcumin may be a potent PON1 inducer in cultured cells in vitro, but not in the liver of curcumin-fed mice because of its low concentrations in vivo.
Protective effects of brain-derived neurotrophic factor on the noise-damaged cochlear spiral ganglion
Authors: Zhai S-Q , Guo W , Hu Y-Y , Yu N , Chen Q , Wang J-Z , Fan M , Yang W-Y 
Published: November 2010

AbstractObjective:To explore the protective effects of brain-derived neurotrophic factor on the noise-damaged cochlear spiral ganglion.Methods:Recombinant adenovirus brain-derived neurotrophic factor vector, recombinant adenovirus LacZ and artificial perilymph were prepared. Guinea pigs with audiometric auditory brainstem response thresholds of more than 75 dB SPL, measured seven days after four hours of noise exposure at 135 dB SPL, were divided into three groups. Adenovirus brain-derived neurotrophic factor vector, adenovirus LacZ and perilymph were infused into the cochleae of the three groups, variously. Eight weeks later, the cochleae were stained immunohistochemically and the spiral ganglion cells counted.Results:The auditory brainstem response threshold recorded before and seven days after noise exposure did not differ significantly between the three groups. However, eight weeks after cochlear perfusion, the group receiving brain-derived neurotrophic factor had a significantly decreased auditory brainstem response threshold and increased spiral ganglion cell count, compared with the adenovirus LacZ and perilymph groups.Conclusion:When administered via cochlear infusion following noise damage, brain-derived neurotrophic factor appears to improve the auditory threshold, and to have a protective effect on the spiral ganglion cells.
Bronchoscopy versus multi-detector computed tomography in the diagnosis of congenital vascular ring
Authors: Gaafar A H , El-Noueam K I 
Published: November 2010

AbstractBackground:Vascular rings are congenital vascular anomalies of the aortic arch complex which cause compression of the trachea and/or oesophagus. A variety of investigations may lead to diagnosis of these anomalies, including bronchoscopy and computed tomography. During the latter, image acquisition and processing use the multi-detector row technique and new reconstruction algorithms, producing high-resolution images which can be visualised as complex, three-dimensional renditions.Objective:This study aimed to assess and compare the roles of bronchoscopy and multi-detector row computed tomography in the diagnosis of congenital vascular ring.Patients and methods:We included infants and children below the age of 16 years who presented with congenital vascular ring. All patients underwent rigid bronchoscopy under general anaesthesia, with spontaneous respiration. All computed tomography scans were obtained using a 16 multi-detector row computed tomography system, followed by data reconstruction on a three-dimensional workstation.Results:Ten patients with congenital vascular ring were identified (six boys and four girls). Fifty per cent of cases presented within the first year of life. Double aortic arch was the most common anomaly (40 per cent). Bronchoscopy detected external tracheal compression in nine cases (90 per cent). Associated airway lesions were detected endoscopically in three cases. In contrast, multi-detector row computed tomography detected the vascular ring in all cases, with accurate detection of the compressing vessel; however, it did not detect any associated airway lesions.Conclusion:Bronchoscopy and radiological evaluation are essential for the diagnosis and pre-operative evaluation of congenital vascular ring. Multi-detector row computed tomography can provide more information about the nature of the disease, and can facilitate better communication between clinicians, compared with conventional computed tomography.
Parapharyngeal cerebrospinal fluid collection: an unusual complication of temporal bone fracture
Authors: Kirton C , Guidera A 
Published: November 2010

AbstractObjective:We present an unusual case of parapharyngeal cerebrospinal fluid collection causing upper airway obstruction following a temporal bone fracture.Method:Case report and literature review of temporal bone fracture associated with parapharyngeal cerebrospinal fluid collection.Results:A 19-year-old man presented with cerebrospinal fluid otorrhoea and temporal bone fracture following a head injury. He was discharged after 48 hours of observation. The patient returned within 6 hours with sudden unilateral neck swelling and stridor after blowing his nose. Flexible nasendoscopy and computed tomography showed extrinsic compression of the pharynx, with partial upper airway obstruction. A literature review using Pubmed™ and Medline™ identified no previously reported cases of parapharyngeal cerebrospinal fluid collection associated with temporal bone fracture.Conclusion:This case illustrates a previously undescribed complication of temporal bone fracture. Raised intracranial pressure in the presence of a cerebrospinal fluid fistula may lead to airway obstruction, following temporal bone fracture.
Seasonal variation in the effect of climate on the biology of Rhipicephalus sanguineus in southern Europe
Authors: DANTAS-TORRES FILIPE , FIGUEREDO LUCIANA A. , OTRANTO DOMENICO 
Published: November 2010

SUMMARYObjective.Rhipicephalus sanguineus is the most widespread tick in the world and a vector of many pathogens infecting dogs and humans. To date, there have been no investigations on the biology of R. sanguineus under natural Mediterranean climatic conditions. Methods. The biology of R. sanguineus was studied under laboratory and natural climatic conditions in southern Italy. Several biological parameters were compared in different seasons, and their correlation with climatic data was assessed. Results. The life cycle of R. sanguineus lasted for a mean of 101·4 and 116·2 days under laboratory and environmental conditions respectively. Reproductive parameters of wild-collected females kept in the environment in May were significantly different from first-generation females maintained in September–October, and the correlation between reproductive parameters and climate data varied according to season. Conclusion. These results indicate that the Mediterranean climate affects the biology of R. sanguineus, which compensates its losses during the initial phases of its cycle in spring with high feeding and moulting rates of larvae and nymphs during summer as well as with high egg production during autumn. These results advance our knowledge of the biology of R. sanguineus and will be useful for the understanding of the eco-epidemiology of tick-borne diseases that this tick transmits.
Molecular approaches for a better understanding of the epidemiology and population genetics ofLeishmania
Authors: SCHÖNIAN G. , KUHLS K. , MAURICIO I. L. 
Published: November 2010

SUMMARYMolecular approaches are being used increasingly for epidemiological studies of visceral and cutaneous leishmaniases. Several molecular markers resolving genetic differences betweenLeishmaniaparasites at species and strain levels have been developed to address key epidemiological and population genetic questions. The current gold standard, multilocus enzyme typing (MLEE), needs cultured parasites and lacks discriminatory power. PCR assays identifying species directly with clinical samples have proven useful in numerous field studies. Multilocus sequence typing (MLST) is potentially the most powerful phylogenetic approach and will, most probably, replace MLEE in the future. Multilocus microsatellite typing (MLMT) is able to discriminate below the zymodeme level and seems to be the best candidate for becoming the gold standard for distinction of strains. Population genetic studies by MLMT revealed geographical and hierarchic population structure inL. tropica, L. majorand theL. donovanicomplex. The existence of hybrids and gene flow betweenLeishmaniapopulations suggests that sexual recombination is more frequent than previously thought. However, typing and analytical tools need to be further improved. Accessible databases should be created and sustained for integrating data obtained by different researchers. This would allow for global analyses and help to avoid biases in analyses due to small sample sizes.
Voxel-based meta-analysis of regional white-matter volume differences in autism spectrum disorderversushealthy controls
Authors: Radua J. , Via E. , Catani M. , Mataix-Cols D. 
Published: November 2010

BackgroundWe conducted a meta-analysis of voxel-based morphometry (VBM) studies in autism spectrum disorder (ASD) to clarify the changes in regional white-matter volume underpinning this condition, and generated an online database to facilitate replication and further analyses by other researchers.MethodPubMed, ScienceDirect, Web of Knowledge and Scopus databases were searched between 2002 (the date of the first white-matter VBM study in ASD) and 2010. Manual searches were also conducted. Authors were contacted to obtain additional data. Coordinates were extracted from clusters of significant white-matter difference between patients and controls. A new template for white matter was created for the signed differential mapping (SDM) meta-analytic method. A diffusion tensor imaging (DTI)-derived atlas was used to optimally localize the changes in white-matter volume.ResultsThirteen datasets comprising 246 patients with ASD and 237 healthy controls met inclusion criteria. No between-group differences were found in global white-matter volumes. ASD patients showed increases of white-matter volume in the right arcuate fasciculus and also in the left inferior fronto-occipital and uncinate fasciculi. These findings remained unchanged in quartile and jackknife sensitivity analyses and also in subgroup analyses (pediatricversusadult samples).ConclusionsPatients with ASD display increases of white-matter volume in tracts known to be important for language and social cognition. Whether the results apply to individuals with lower IQ or younger age and whether there are meaningful neurobiological differences between the subtypes of ASD remain to be investigated.