bluuebunny/crossref_metadata_2025 huggingface dataset:
Long Term Testing in Continuous Mode of HT‐PEMFC Based H3PO4/PBI Celtec‐P MEAs for μ‐CHP Applications
Authors: Moçotéguy Ph. , Ludwig B. , Scholta J. , Barrera R. , Ginocchio S.
Published: July 2009

Single cell and 500 We stack integrating Celtec P1000 MEAs were operated in continuous mode at 0.4 A cm–2 and 160 °C, under simulated reformate and air. Single cell's ohmic resistivity was almost unaffected by 1,100 h of ageing but the cell progressively switched from a cathodic to an anodic mass transfer limited operation. The stack was operated for 658 h, exhibiting the same behaviour and an additional increase in cell voltage distribution heterogeneity. CO2 proved to have negligible effect on performances but performance losses induced by ageing are doubled in the presence of CO. Post‐testing experiments revealed that anode electrochemical active area was dramatically decreased and that platinum content was also decreased. Finally, results showed that a convenient shut‐down procedure could prevent or limit degradations associated with storage.
Determination of the Potentiostatic Stability of PEMFC Electro Catalysts at Elevated Temperatures
Authors: Dam V. A. T. , Jayasayee K. , de Bruijn F. A.
Published: July 2009

The electrochemical stability of platinum on carbon catalyst (Hispec™ 4000, Johnson Matthey) has been investigated predominantly at constant potentials ranging from 0.95 to 1.25 V at elevated temperatures. By combining a quartz crystal microbalance (QCM) with electrochemical techniques, dynamic insight is obtained on the oxidation and corrosion of both platinum and carbon during potentiostatic hold. From the cyclic voltammetry (CV) data, it can be concluded that at all conditions, the platinum surface area decreases when Pt on carbon catalysts are exposed to a constant potential of 1.05 to 1.25 V. Under the applied conditions, this loss of surface area is primarily caused by the dissolution of platinum.

Both the QCM as well as on‐line electrochemical mass spectrometry (OLEMS) experiments show that the corrosion of carbon is catalysed by the presence of platinum at 80 °C, as long as the platinum surface is not passivated by an oxide layer.
Microstructure and Microfabrication Considerations for Self‐Supported On‐Chip Ultra‐Thin Micro‐Solid Oxide Fuel Cell Membranes
Authors: Lai B.‐K. , Xiong H. , Tsuchiya M. , Johnson A. C. , Ramanathan S.
Published: July 2009

La0.6Sr0.4Co0.8Fe0.2O3 – δ (LSCF) has been sputtered on bare Si and Si3N4 and yttria‐stabilised zirconia (YSZ) thin films to investigate annealing temperature‐ and thickness‐dependent microstructure and functional properties, as well as their implications for designing failure‐resistant micro‐solid oxide fuel cell (μSOFC) membranes. The LSCF thin films crystallise in the 400–450 °C range; however, after annealing in the 600–700 °C range, cracks are observed. The formation of cracks is also thickness‐dependent. High electrical conductivity, ∼520 Scm–1 at 600 °C, and low activation energy, ∼0.13 eV, in the 400–600 °C range, are still maintained for LSCF films as thin as 27 nm. Based on these studies, a strong correlation between microstructure and electrical conductivity has been observed and an annealing temperature‐thickness design space that is complementary to temperature‐stress design space has been proposed for designing reliable membranes using sputtered LSCF thin films. Microfabrication approaches that maintain the highest possible surface and interface quality of heterostructured membranes have been carefully examined. By taking advantage of the microstructure, microfabrication and geometrical structural considerations, we were able to successfully fabricate large‐area, self‐supported membranes. These results are also relevant to conventional or grid‐supported SOFC membranes using ultrathin nanocrystalline cathodes and μSOFCs using cathode thin films other than LSCF.
The value of mortgage prepayment and default options
Authors: Chen Yong , Connolly Michael , Tang Wenjin , Su Tie
Published: July 2009

We use an implicit alternating direction numerical procedure to estimate the value of a fixed‐rate mortgage (FRM) with embedded default and prepayment options. The value of FRMs depends on interest rates, the house value, and mortgage maturity. Our numerical results suggest that the joint option value of prepayment and default is considerably high, even at loan origination. We extend the model to include prepayment penalties in FRM valuation. © 2009 Wiley Periodicals, Inc. Jrl Fut Mark 29:840–861, 2009
An explicitly solvable multi‐scale stochastic volatility model: Option pricing and calibration problems
Authors: Fatone Lorella , Mariani Francesca , Recchioni Maria Cristina , Zirilli Francesco
Published: July 2009

We introduce an explicitly solvable multiscale stochastic volatility model that generalizes the Heston model. The model describes the dynamics of an asset price and of its two stochastic variances using a system of three Ito stochastic differential equations. The two stochastic variances vary on two distinct time scales and can be regarded as auxiliary variables introduced to model the dynamics of the asset price. Under some assumptions, the transition probability density function of the stochastic process solution of the model is represented as a one‐dimensional integral of an explicitly known integrand. In this sense the model is explicitly solvable. We consider the risk‐neutral measure associated with the proposed multiscale stochastic volatility model and derive formulae to price European vanilla options (call and put) in the multiscale stochastic volatility model considered. We use the thus‐obtained option price formulae to study the calibration problem, that is to study the values of the model parameters, the correlation coefficients of the Wiener processes defining the model, and the initial stochastic variances implied by the “observed” option prices using both synthetic and real data. In the analysis of real data, we use the S&P 500 index and to the prices of the corresponding options in the year 2005. The web site http://www.econ.univpm.it/recchioni/finance/w7 contains some auxiliary material including some animations that helps the understanding of this article. A more general reference to the work of the authors and their coauthors in mathematical finance is the web site http://www.econ.univpm.it/recchioni/finance. © 2009 Wiley Periodicals, Inc. Jrl Fut Mark 29:862–893, 2009
Identifying the molecular signature of the interstitial deletion 7q subgroup of uterine leiomyomata using a paired analysis
Authors: Hodge Jennelle C. , Park Peter J. , Dreyfuss Jonathan M. , Assil‐Kishawi Iman , Somasundaram Priya , Semere Luwam G. , Quade Bradley J. , Lynch Allison M. , Stewart Elizabeth A. , Morton Cynthia C.
Published: July 2009

Uterine leiomyomata (UL), the most common neoplasm in reproductive‐age women, have recurrent cytogenetic abnormalities including interstitial deletion of 7q. To develop a molecular signature, matched del(7q) and non‐del(7q) tumors identified by FISH or karyotyping from 11 women were profiled with expression arrays. Our analysis using paired t tests demonstrates this matched design is critical to eliminate the confounding effects of genotype and environment that underlie patient variation. A gene list ordered by genome‐wide significance showed enrichment for the 7q22 target region. Modification of the gene list by weighting each sample for percent of del(7q) cells to account for the mosaic nature of these tumors further enhanced the frequency of 7q22 genes. Pathway analysis revealed two of the 19 significant functional networks were associated with development and the most represented pathway was protein ubiquitination, which can influence tumor development by stabilizing oncoproteins and destabilizing tumor suppressor proteins. Array CGH (aCGH) studies determined the only consistent genomic imbalance was deletion of 9.5 megabases from 7q22‐7q31.1. Combining the aCGH data with the del(7q) UL mosaicism‐weighted expression analysis resulted in a list of genes that are commonly deleted and whose copy number is correlated with significantly decreased expression. These genes include the proliferation inhibitor HPB1, the loss of expression of which has been associated with invasive breast cancer, as well as the mitosis integrity‐maintenance tumor suppressor RINT1. This study provides a molecular signature of the del(7q) UL subgroup and will serve as a platform for future studies of tumor pathogenesis. © 2009 Wiley‐Liss, Inc.
Colocalization of somatic and meiotic double strand breaks near the Myc oncogene on mouse chromosome 15
Authors: Ng Siemon H. , Maas Sarah A. , Petkov Petko M. , Mills Kevin D. , Paigen Kenneth
Published: July 2009

Both somatic and meiotic recombinations involve the repair of DNA double strand breaks (DSBs) that occur at preferred locations in the genome. Improper repair of DSBs during either mitosis or meiosis can lead to mutations, chromosomal aberration such as translocations, cancer, and/or cell death. Currently, no model exists that explains the locations of either spontaneous somatic DSBs or programmed meiotic DSBs or relates them to each other. One common class of tumorigenic translocations arising from DSBs is chromosomal rearrangements near the Myc oncogene. Myc translocations have been associated with Burkitt lymphoma in humans, plasmacytoma in mice, and immunocytoma in rats. Comparing the locations of somatic and meiotic DSBs near the mouse Myc oncogene, we demonstrated that the placement of these DSBs is not random and that both events clustered in the same short discrete region of the genome. Our work shows that both somatic and meiotic DSBs tend to occur in proximity to each other within the Myc region, suggesting that they share common originating features. It is likely that some regions of the genome are more susceptible to both somatic and meiotic DSBs, and the locations of meiotic hotspots may be an indicator of genomic regions more susceptible to DNA damage. © 2009 Wiley‐Liss, Inc.
Are there any more ovarian tumor suppressor genes? A new perspective using ultra high‐resolution copy number and loss of heterozygosity analysis
Authors: Gorringe Kylie L. , Ramakrishna Manasa , Williams Louise H. , Sridhar Anita , Boyle Samantha E. , Bearfoot Jennifer L. , Li Jason , Anglesio Michael S. , Campbell Ian G.
Published: July 2009

Ovarian cancer is characterized by complex genetic alterations, including copy number loss and copy number‐neutral loss of heterozygosity (LOH). These alterations are assumed to represent the “second hit” of the underlying tumor suppressor gene (TSG), however, relative to the number of LOH hotspots reported, few ovarian TSGs have been identified. We conducted a high‐resolution LOH analysis using SNP arrays (500K and SNP6.0) of 106 primary ovarian tumors of various histological subtypes together with matching normal DNA. LOH was detected in at least 35% of samples on chromosomes 17, 19p, 22q, Xp, 13q, 8p, 6q, 4q, 5q, 1p, 16q, and 9q with a median minimal region of overlap of only 300 kb. Subtype‐specific differences in LOH frequency were noted, particularly for mucinous cases. We also identified 192 somatic homozygous deletions (HDs). Recurrent HDs targeted known TSGs such as CDKN2A (eight samples), RB1 (five samples), and PTEN (three samples). Additional recurrent HDs targeted 16 candidate TSGs near minimal regions of LOH on chromosomes 17, 13, 8p, 5q, and X. Given the importance of HDs in inactivating known genes, these candidates are highly likely to be ovarian TSGs. Our data suggest that the poor success of previous LOH studies was due to the inability of previous technology to resolve complex genomic alterations and distinguish true LOH from allelic imbalance. This study shows that recurrent regions of LOH and HD frequently align with known TSGs suggesting that LOH analysis remains a valid approach to discovering new candidates. © 2009 Wiley‐Liss, Inc.
Pathological amygdala activation during working memory performance: Evidence for a pathophysiological trait marker in bipolar affective disorder
Authors: Gruber Oliver , Tost Heike , Henseler Ilona , Schmael Christine , Scherk Harald , Ende Gabriele , Ruf Matthias , Falkai Peter , Rietschel Marcella
Published: July 2009

Recent evidence suggests that deficits of working memory may be a promising neurocognitive endophenotype of bipolar affective disorder. However, little is known about the neurobiological correlates of these deficits. The aim of this study was to determine possible pathophysiological trait markers of bipolar disorder in neural circuits involved in working memory. Functional magnetic resonance imaging was performed in 18 euthymic bipolar patients and 18 matched healthy volunteers using two circuit‐specific experimental tasks established by prior systematic neuroimaging studies of working memory. Both euthymic bipolar patients and healthy controls showed working memory‐related brain activations that were highly consistent with findings from previous comparable neuroimaging studies in healthy subjects. While these patterns of brain activation were completely preserved in the bipolar patients, only the patients exhibited activation of the right amygdala during the articulatory rehearsal task. In the same task, functional activation in right frontal and intraparietal cortex and in the right cerebellum was significantly enhanced in the patients. These findings indicate that the right amygdala is pathologically activated in euthymic bipolar patients during performance of a circuit‐specific working memory task (articulatory rehearsal). This pathophysiological abnormality appears to be a trait marker in bipolar disorders that can be observed even in the euthymic state and that seems to be largely independent of task performance and medication. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.
Metaanalytic connectivity modeling: Delineating the functional connectivity of the human amygdala
Authors: Robinson Jennifer L. , Laird Angela R. , Glahn David C. , Lovallo William R. , Fox Peter T.
Published: July 2009

Functional neuroimaging has evolved into an indispensable tool for noninvasively investigating brain function. A recent development of such methodology is the creation of connectivity models for brain regions and related networks, efforts that have been inhibited by notable limitations. We present a new method for ascertaining functional connectivity of specific brain structures using metaanalytic connectivity modeling (MACM), along with validation of our method using a nonhuman primate database. Drawing from decades of neuroimaging research and spanning multiple behavioral domains, the method overcomes many weaknesses of conventional connectivity analyses and provides a simple, automated alternative to developing accurate and robust models of anatomically‐defined human functional connectivity. Applying MACM to the amygdala, a small structure of the brain with a complex network of connections, we found high coherence with anatomical studies in nonhuman primates as well as human‐based theoretical models of emotive‐cognitive integration, providing evidence for this novel method's utility. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.
Addressing a systematic vibration artifact in diffusion‐weighted MRI
Authors: Gallichan Daniel , Scholz Jan , Bartsch Andreas , Behrens Timothy E. , Robson Matthew D. , Miller Karla L.
Published: July 2009

We have identified and studied a pronounced artifact in diffusion‐weighted MRI on a clinical system. The artifact results from vibrations of the patient table due to low‐frequency mechanical resonances of the system which are stimulated by the low‐frequency gradient switching associated with the diffusion‐weighting. The artifact manifests as localized signal‐loss in images acquired with partial Fourier coverage when there is a strong component of the diffusion‐gradient vector in the left–right direction. This signal loss is caused by local phase ramps in the image domain which shift the apparent k‐space center for a particular voxel outside the covered region. The local signal loss masquerades as signal attenuation due to diffusion, severely disrupting the quantitative measures associated with diffusion‐tensor imaging (DTI). We suggest a way to improve the interpretation of affected DTI data by including a co‐regressor which accounts for the empirical response of regions affected by the artifact. We also demonstrate that the artifact may be avoided by acquiring full k‐space data, and that subsequent increases in TE can be avoided by employing parallel acceleration. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.
Syntheses and fluoride‐ion‐mediated hydrolysis of phosphoroselenoic acid ester and amides
Authors: Murai Toshiaki , Inaji Shinsuke , Takenaka Tohru
Published: July 2009

Phosphoroselenoic acid ester and amides containing binaphthoxy moiety were prepared by reacting phosphoroselenoyl chloride with alcohols and secondary amines. The resulting amides underwent fluoride‐ion‐mediated hydrolysis with a THF solution of tetrabutylammonium fluoride to give two types of phosphoroselenoic acid ammonium salts: one with a fluorine atom and another with a binaphthoxy group on the phosphorus atom. The ratio of these products depended on the substituents on the nitrogen atom of the amides. A similar reaction of the ester with tetrabutylammonium fluoride gave two types of ammonium salts. The formation of these products was confirmed by converting them to the corresponding methyl esters. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:255–261, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20544
From learning to forgetting: Behavioral, circuitry, and molecular properties define the different functional states of the recognition memory trace
Authors: Romero‐Granados Rocío , Fontán‐Lozano Ángela , Delgado‐García José María , Carrión Ángel M.
Published: July 2009

Neuropsychological analyses of amnesic patients, as well as lesion experiments, indicate that the temporal lobe is essential for the encoding, storage, and expression of object recognition memory (ORM). However, temporal lobe structures directly involved in the consolidation and reconsolidation of these memories are not yet well‐defined. We report here that systemic administration of a protein synthesis inhibitor before or up to 4 h after training or reactivation sessions impairs consolidation and reconsolidation of ORM, without affecting short‐term memory. We have also observed that ORM reconsolidation is sensitive to protein synthesis inhibition, independently of the ORM trace age. Using bdnf and egr‐1 gene expression analysis, we defined temporal lobe areas related to consolidation and reconsolidation of ORM. Training and reactivation 21 days after ORM acquisition sessions provoked changes in bdnf mRNA in somatosensory, perirhinal, and hippocampal cortices. Reactivation 2 days after the training session elicited changes in bdnf and egr‐1 mRNA in entorhinal and prefrontal cortices, while reactivation 9 days post‐training provoked an increase in egr‐1 transcription in somatosensory and entorhinal cortices. The differences in activated circuits and in the capacity to recall the memory trace after 9 or 21 days post‐training suggest that memory trace suffers functional changes in this period of time. All these results indicate that the functional state of the recognition memory trace, from acquisition to forgetting, can be specifically defined by behavioral, circuitry, and molecular properties. © 2009 Wiley‐Liss, Inc.
Reduction of TrkB expression de novo in the adult mouse impairs epileptogenesis in the kindling model
Authors: Kotloski Robert , McNamara James O.
Published: July 2009

Elucidating the mechanisms of epileptogenesis in molecular terms can identify targets for therapies aimed at preventing epileptogenesis or limiting its progression. Genetic perturbations have implicated signaling by the neurotrophin, BDNF, and its receptor, TrkB, in limbic epileptogenesis. Whether this signaling is critical to epileptogenesis in the adult brain is unclear. We sought to determine whether reduced expression of TrkB de novo in the mature brain is sufficient to impair epileptogenesis in the kindling model. Treatment of adult Act‐CreER TrkBflox/flox mice with tamoxifen resulted in modest reductions of TrkB protein expression de novo in the adult that were detected in hippocampus but not other brain regions. Modest reduction of hippocampal TrkB content inhibited epileptogenesis induced by stimulation of hippocampus or amygdala. The data support the conclusion that reduction of TrkB expression in hippocampus de novo in the mature brain impairs epileptogenesis in the kindling model. These findings advance TrkB and its downstream signaling pathways as attractive targets for limiting the progression of epileptogenesis. © 2009 Wiley‐Liss, Inc.
Further examination of the convergent and discriminant validity of the student–teacher relationship scale
Authors: Doumen Sarah , Verschueren Karine , Buyse Evelien , De Munter Sofie , Max Kristel , Moens Loth
Published: July 2009

Two studies extended psychometric research on the Student–Teacher Relationship Scale (STRS) with kindergarten and preschool children (N1 = 60–71; N2 = 35) and their teachers. These studies used a multi‐method approach to replicate and extend previous findings concerning the convergent validity of the STRS Closeness, Conflict, and Dependency scale and to further examine the discriminant validity of the STRS. Study 1 investigated convergence between the STRS scales and child‐ and peer‐reports of the same constructs based on a multi‐trait multi‐method approach. Study 2 examined the pattern of associations between the STRS and indicators of teacher–child relationship quality rated by external observers. Support was found for the convergent validity and to a lesser extent the discriminant validity of the STRS Closeness and Conflict scale. For the STRS Dependency scale, additional research remains necessary. Copyright © 2009 John Wiley & Sons, Ltd.
Dynamic visualization of signal transduction in living cells: From second messengers to kinases
Authors: Herbst Katie J. , Ni Qiang , Zhang Jin
Published: July 2009

The study of signal transduction, or the highly regulated series of biochemical events which allow a cell to convert a given stimulus into a functional response, has seen a paradigm shift with a recent explosion in the number of genetically encoded FRET‐based biosensors capable of detecting spatial and temporal regulation of various signaling events in living cells. The two classes of biosensors discussed, namely kinase activity and second messenger biosensors, utilize two fluorescent proteins (FP) suitable for FRET and convert a signaling event of interest into a conformational change in the biosensor that can be measured as a change in FRET between the two FPs. Individually, these biosensors have been used to elucidate many complex signal transduction mechanisms in various biological systems. However, it has become increasingly clear that it is often more desirable to study multiple signaling events simultaneously, allowing for precise correlation of the temporal profiles of multiple signaling molecules without the complication of cell to cell variability. With the design of spectrally distinct biosensors and new coimaging strategies, simultaneous imaging of multiple signaling events is not only possible, but has aided in mapping the intricate network of cellular signal transduction cascades. Furthermore, as aberrant signal transduction involving second messengers and kinases is implicated in numerous disease states, it is hopeful that these FRET‐based biosensors and coimaging strategies can help to unravel the molecular links between altered signal transduction and certain disease states. © 2009 IUBMB IUBMB Life 61(9): 902–908, 2009
Semiparametric estimation of consumer demand systems in real expenditure
Authors: Pendakur Krishna , Sperlich Stefan
Published: July 2009

Microdata concerning consumer demand typically show considerable variation in real expenditures, but very little variation in prices. We propose a semiparametric strategy for the consumer demand problem in which expenditure share equations are estimated nonparametrically in the real expenditure direction and estimated parametrically (with fixed or varying coefficients) in price directions. In our model, Engel curves are unrestricted: demands may have any rank. Because the demand model is derived from a cost function, it may be restricted to satisfy integrability and used for consumer surplus calculations. Since real expenditure is unobserved, but rather estimated under the model, we face a semiparametric model with a nonparametrically generated regressor. We show efficient convergence rates for parametric and nonparametric components. We illustrate the feasibility of our proposed strategy using Canadian expenditure and price data: Engel curves display curvature which cannot be encompassed by standard parametric models. We also find that the rationality restriction of Slutsky symmetry is rejected in the fixed‐coefficients model, but not in the varying‐coefficients model. Copyright © 2009 John Wiley & Sons, Ltd.
RUNX3‐mediated repression of RUNX1 in B cells
Authors: Brady Gareth , Farrell Paul J.
Published: July 2009

Are there three different RUNX genes in the human genome just to allow differential expression in different cell types or are the RUNX proteins functionally different? Much previous evidence has suggested that the RUNX proteins were functionally redundant but, in human B cells, RUNX1 and RUNX3 have clearly been shown to have different functions at a key developmental stage. RUNX1 is expressed in mature resting B cells but proliferating B cell lines express RUNX3. Repression of RUNX1 by RUNX3 is required to allow the cell proliferation and this provides an experimental system to investigate the mechanism of the different activities of RUNX1 and RUNX3 in these cells. J. Cell. Physiol. 221: 283–287, 2009. © 2009 Wiley‐Liss, Inc.
TMSCl‐mediated one‐pot, three‐component synthesis of 2H‐indazolo[2,1‐b]phthalazine‐triones
Authors: Nagarapu Lingaiah , Bantu Rajashaker , Mereyala Hari Babu
Published: July 2009

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A simple, efficient, and cost‐effective method for the synthesis of 2H‐indazolo[2,1‐b]phthalazine‐1,6,11(13H)‐trione derivatives by a one‐pot, three‐component condensation reaction of phthalazide, dimedone, or 1,3‐cyclohexanedione and aromatic aldehydes under CH3CN/DMF (8:2) media at 80°C for 30–60 min in the presence of trimethylsilyl chloride (TMSCl) is described. J. Heterocyclic Chem., (2009).
Utilization of 2‐benzo[b]furan carboxylic acid hydrazide in the synthesis of 1,3,4‐oxadiazole derivatives
Authors: Da Yu‐Xia , Yang Zhi , Quan Zheng‐Jun , Zhang Zhang , Wang Xi‐Cun
Published: July 2009

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In this study, the synthesis of series of 2‐benzo[b]furan‐substituted 1,3,4‐oxadiazole derivatives using readily available 2‐benzo[b]furan carboxylic acid hydrazide as starting material has been investigated. J. Heterocyclic Chem., (2009).
Friedel‐Crafts heteroarylation of (hetero)arenes: A facile entry to 4‐(hetero)aryl quinazolines and quinolines
Authors: Kumar Shailesh , Sahu Devi Prasad
Published: July 2009

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Anhydrous AlCl3‐mediated heteroarylation of various arenes and heteroarenes with 2,4‐dichloro‐quinazoline (1) and 4‐chloroquinoline (4) afforded exclusively 4‐aryl/heteroarylquinazolines (3) and 4‐aryl/heteroarylquinolines (5), respectively. Compared with the available synthetic protocols, aluminum chloride induced CC bond formation is direct and convenient to access bis‐(hetero)aryl quinazolines and quinolines. The products were obtained in good to excellent yields by this method. J. Heterocyclic Chem., (2009).
An efficient two‐step synthesis of novel thiazolo[2,3‐b]pyrazolo[3,4‐f][1,3,5]triazepines
Authors: Insuasty Braulio , Tigreros Alexis , Martínez Henry , Quiroga Jairo , Abonia Rodrigo , Gutierrez Alexander , Nogueras Manuel , Cobo Justo
Published: July 2009

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In an attempt to carry out a straightforward synthesis of thiazolopyrazolodiazepines from the reaction of 4,5‐diamino‐3‐methyl‐1‐phenylpyrazole 1 with arylidene derivatives of rhodanine 2, the unplanned (Z)‐2′‐[(5‐amino‐3‐methyl‐1‐phenylpyrazol‐4‐yl)imino]‐5‐arylidenethiazolidin‐4‐ones 4 were obtained as unique products. Nevertheless, the treatment of these compounds with aliphatic aldehydes in dimethylformamide provided the novel thiazolo[2,3‐b]pyrazolo[3,4‐f][1,3,5]triazepines 5 and 6 in good to excellent yields. All the structures of the obtained compounds were assigned on the basis of IR, 1D and 2D NMR measurements, mass spectrometry, and microanalysis. J. Heterocyclic Chem., (2009).
Unusual retention of isoxazole ring under the influence of 3‐(substituted nitrophenyl)‐2‐isoxazoline during catalytic hydrogenation of isoxazoline‐substituted isoxazole systems
Authors: Singh Vijay , Hutait Samiran , Yadav Gaya P. , Maulik Prakas R. , Batra Sanjay
Published: July 2009

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The cleavage of the isoxazole ring during the Raney‐Ni‐promoted catalytic hydrogenation is prevented under the influence of 3‐(substituted nitrophenyl)‐2‐isoxazoline in isoxazoline‐substituted isoxazole systems produced via 1,3‐dipolar cycloaddition either on the Baylis–Hillman derivatives or Grignard products. Unexpectedly, the hydrogenations in these diastereomeric compounds were observed to exclusively yield products, wherein the methoxycarbonyl and the hydroxyl or the acetyl groups exist syn to each other. J. Heterocyclic Chem., (2009).
Degenerative and regenerative processes involved in midgut pseudotumor formation in the stick insect (Carausius morosus)
Authors: Hoffmann Paul , Holtmann Matthias , Dorn August
Published: July 2009

Spontaneous and experimentally induced pseudotumor formation in Carausius morosus impairs the midgut tissue homeostasis. Spontaneous pseudotumor formation begins by the break down of a single or a small group of columnar cells (CCs) and is followed by the degeneration of neighboring CCs. There are not only marked similarities but also decisive differences between normal dying CCs in healthy specimens and the degeneration of CCs leading to pseudotumors: in both cases, the apical cell parts with the nucleus are extruded into the midgut lumen, but only during of pseudotumor formation an “amorphous substance” originates from the basal parts of the CCs. Hemocytes are attracted to this substance and form a nodule‐like aggregation, which is responsible for the phenotype of pseudotumors. Pseudotumor infestation has also an impact on the midgut nidi, which consist of an intestinal stem cell and several CC progenitor cells. In healthy specimens only one progenitor cell per nidus differentiates at a time, but, several to all progenitor cells differentiate simultaneously in pseudotumor‐infested specimens. Extirpation of the ingluvial ganglion in healthy specimens results in an immediate onset of pseudotumor formation and a dramatic acceleration of pseudotumor growth. Importantly, the ultrastructural characteristics of spontaneous and experimentally induced pseudotumors are identical. This supports the idea that the stomatogastric nervous system plays an integral role in the maintenance of midgut tissue homeostasis. J. Morphol., 2009. © 2009 Wiley‐Liss, Inc.
Ontogeny, variation, and homology in Salvelinus alpinus caudal skeleton (Teleostei: Salmonidae)
Authors: Grünbaum Thomas , Cloutier Richard
Published: July 2009

The ontogeny of the caudal skeleton in the Arctic charr, Salvelinus alpinus was examined using an extensive series of cleared and stained specimens. We demonstrate the presence of skeletal components never reported previously within the Salmonidae. In contrast to the generalized condition for salmonids, seven hypurals (instead of six), and four uroneurals (instead of three) have been found in some specimens. Variation in the number and condition of epurals is documented. New hypotheses are proposed concerning (1) relationships among centra and their associated elements, (2) phylogenetic distribution of caudal characters within the Salmonidae, and (3) homology of caudal components. Using the published phylogenetic hypotheses, we provide evidence, that a seventh hypural and a fourth uroneural are taxic atavism in salmonids. The development of the salmonid homocercal fin is discussed in the light of a polyural scheme based on evidences of a one‐to‐one relationship among ural centra and their associated elements. J. Morphol., 2010. © 2009 Wiley‐Liss, Inc.
Fused‐core, sub‐2 μm packings, and monolithic HPLC columns: a comparative evaluation
Authors: Brice Richard W. , Zhang Xin , Colón Luis A.
Published: July 2009

Three different HPLC column technologies (i.e., monolith, fused‐core particles, and sub‐2 μm particles) were evaluated, comparing van Deemter plots, speed of analysis, back pressure, and mobile phase consumption. Very high linear velocities (˜12 mm/s) were achieved with the monolithic column using modest pressure (110 bar) at the expense of high mobile phase consumption. The minimum plate height of the monolith was similar to that of a 3 μm‐particle packed column (i.e., h = 8 μm), operated at optimal linear velocities; the monolithic column showed substantially lower mass transfer dependence, however. The 2.7 μm fused‐core packing material yielded efficiencies closer to the sub‐2 μm material than to the 3 μm‐particle packed column and could be operated at high flow rates. The fused‐core column was able to achieve linear velocities similar to those attained on the sub‐2 μm column, staying below 620 bar instead of almost near 1030 bar required by the sub‐2 μm material. The lack of pH stability of the monolithic column prevented its use to separate basic compounds (i.e., tricyclic antidepressants) at high pH. Best separation of these components at high pH was achieved using the column packed with 1.7 μm hybrid material.
Interpretive optimisation of organic solvent content and flow‐rate in the separation of β‐blockers with a Chromolith RP‐18e column
Authors: Pous‐Torres Sandra , Torres‐Lapasió José. R. , Ruiz‐Ángel Maria J. , García‐Álvarez‐Coque Maria C.
Published: July 2009

The chromatographic performance of a Chromolith RP‐18e column was comprehensively examined for a group of basic drugs (β‐blockers), eluted with isocratic ACN–water mixtures at increasing flow‐rate up to 6 mL/min. As the flow‐rate increases at fixed mobile phase composition, peak distribution (selectivity) is maintained, but the relative peak widths increase. This reduces the resolution below satisfactory values for closely eluting compounds. With the monolithic column, flow‐rate becomes thus an important factor to be optimised, in addition to the mobile phase composition. Since, theoretically, retention factors (k) are independent of the flow‐rate, the classical quadratic model relating log k with the solvent content allows the prediction of the retention at any combination of organic solvent content and flow‐rate. The small deviations found for the most retained compounds were corrected by including, in the quadratic model, an additional term correlating linearly log k with the flow‐rate. Peak shape and resolution changes were predicted by taking advantage of the approximated linear relationships between peak half‐widths and retention times, which offered similar coefficients for peaks eluting at different organic solvent contents and flow‐rates. The accuracy of the predictions in critical conditions was experimentally verified to be satisfactory.
Hydrosilylated allyl‐silica hybrid monolithic columns
Authors: Li Li , Colón Luis A.
Published: July 2009

Organic–inorganic silica hybrid monolithic columns were synthesized containing an allyl pendant. The ally‐monolithic columns were then modified via hydrosilylation reactions to introduce further surface functionalization. The approach was demonstrated by functionalizing allyl‐monolytic columns with n‐octyl‐dimethylsilane (C8‐DMS) and benzyl‐dimethylsilane (benzyl‐DMS). Of the surface available ally groups on the hybrid monolith (i.e., 6.79 μmol/m2), 31.3% reacted via hydrosilylation, resulting in a C8 surface coverage of 2.12 μmol/m2. When using benzyl‐DMS, a surface coverage of 1.95 μmol/m2 was calculated for the benzyl groups. The retentivity of the hybrid monolithic columns increased considerably after the hydrosilylation, as monitored by CLC and CEC. The largest increase in retention was observed with the C8 modified monolith. The hybrid monolithic columns showed higher hydrolytic stability than monolithic columns prepared by the conventional silanoxane bonding of alkyl chlorosilanes modification. The ally‐monolithic column provides a platform for the fabrication of hybrid monoliths that can be conveniently modified by means of hydrosilylation, tailoring the surface of the material. The approach is a promising method to prepare hybrid monolithic columns with versatile stationary phases in a simple and efficient manner.
Application of monolithic columns in pharmaceutical analysis. Determination of indomethacin and its degradation products
Authors: Žáková Petra , Sklenářová Hana , Nováková Lucie , Hájková Renata , Matysová Ludmila , Solich Petr
Published: July 2009

Comparison of HPLC methods using conventional particle‐based and monolithic columns for determination of indomethacin and its two degradation products, viz. 5‐methoxy‐2‐methylindoleacetic acid and 4‐chlorobenzoic acid, was carried out. Ketoprofen was used as an internal standard for data evaluation throughout the study. Conventional separation was based on analytical column Zorbax SB‐Phenyl (75×4.6 mm; 3.5 μm particles) used with a mobile phase composition of acetonitrile and phosphoric acid 0.2% (50:50, v/v) and isocratic flow at 0.6 mL/min. Three different lengths of Chromolith columns RP‐18e (25×4.6 mm, 50×4.6 mm, and 100×3 mm) were tested with respect to the validation parameters peak asymmetry, resolution, height equivalent to a theoretical plate, repeatability, and after optimisation compared to values obtained using a conventional Zorbax column. The developed methods were used to determine all three compounds in a pharmaceutical formulation – Indobene gel. Chromatographic parameters were comparable to those of a conventional particle‐based column. The analysis time was shortened as expected (retention times were lowered by a factor of two). Moreover, the repeatability of peak areas and retention times obtained with a 50 mm monolithic column was greatly improved (RSD values were lower than 0.40%).
A computer prototype to support knowledge audits in organizations
Authors: Perez‐Soltero Alonso , Barcelo‐Valenzuela Mario , Sanchez‐Schmitz Gerardo , Rodriguez‐Elias Oscar Mario
Published: July 2009

A knowledge audit is a process whose purpose is to diagnose the situation in which knowledge is kept within an organization, that is, it allows to know what knowledge exists, who has it, where it is, how it moves and how it is managed. The aim of this paper is to present the implementation of an ontology as a support to knowledge audit process through a computer prototype. A case study in an organization is developed, in which the knowledge audit process is supported by the prototype. Among the advantages it offers: facilitates obtaining knowledge inventory, classifying and valuing knowledge assets and flows, identifying knowledge gaps, knowledge management analysis and reusing the audit's results. Copyright © 2009 John Wiley & Sons, Ltd.
Water‐Soluble Conjugated Polyelectrolyte‐Based Fluorescence Enzyme Coupling Protocol for Continuous and Sensitive β‐Galactosidase Detection
Authors: Feng Fude , Liu Libing , Wang Shu
Published: July 2009

A simple, rapid, continuous and homogeneous fluorescent assay for β‐galactosidase was developed, combining an enzyme‐coupled reaction and signal amplification property of conjugated polyelectrolytes (CPs). The procedure is based on a sequence of two coupled biocatalytic steps in which the β‐galactosidase hydrolyzes its substrate to a phenol derivative followed by conversion to quinone (secondary product) with fluorescence quenching ability by the tyrosinase. The fluorescence of PFP−SO is efficiently quenched by the quinone via an electron transfer process. The limit of detection (LOD) of this assay is less than 0.0005 U · mL−1, which is better than that of electrochemical method and is comparable to that of most sensitive chemiluminescent techniques. In principle, this sensor mechanism will extend the application window of CPs for wide‐spectrum enzyme detections. This “mix‐and‐detect” approach could be expanded to a high‐throughput manner.

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Adenylosuccinate synthetase 1 gene is a novel target of deletion in lung adenocarcinoma
Authors: Miller Joshua C. , Blake Daniel C. , Herzog Christopher R.
Published: July 2009

Tobacco smoke consists of numerous carcinogens whose effect on lung tumor development includes the induction of mutations in key genes as well as the induction of chromosome instability (CIN). Consequently, carcinogen‐induced mouse lung adenocarcinomas (LAC) display many more recurrent site‐ and chromosome‐specific changes in DNA copy number compared with noninduced LAC. Here we identified the Adenylosuccinate synthetase 1 (Adss1) gene located on distal chromosome 12q as a focus of bi‐allelic or homozygous deletion (HD) in LAC. HDs of Adss1 were detected in 10 out of 84 carcinogen‐induced mouse primary LAC and mouse LAC cell lines. In only four of these cases did the deletions affect either Siva1 or Inverted‐formin 2 (Inf2), which immediately flank the Adss1 locus, indicating that Adss1 is a selective target of deletion in LAC. Losses of Adss1 not meeting the quantitative threshold of HD were detected in 36 out of 84 (42.9%) of the mouse tumors and cell lines. A similar frequency of ADSS1 deletion was observed in human LAC cell lines, suggesting relevance in human lung cancer. Adss1 losses were also found to be significantly associated with a more extensive CIN phenotype in the primary mouse tumors. These results implicate ADSS1 inactivation as a novel somatic alteration in lung carcinogenesis, and suggest that its selective deletion in LAC may be triggered by CIN. © 2009 Wiley‐Liss, Inc.
Recent European Food Safety Authority toxicological evaluations of major phthalates used in food contact materials
Authors: Lhuguenot Jean‐Claude
Published: July 2009

During the 1980s and 1990s, and at the EU level, the Scientific Committee for Food evaluated a number of phthalates that were being used, or were requested for use, as additives in plastics. At this time, peroxisome proliferation was considered as the pivotal effect on which toxicological evaluation of these chemicals was based. At the end of 1990s, a general consensus has been agreed that rodents are highly sensitive to the phenomenon of peroxisome proliferation and that this particular effect should not be used for human risk assessment. Consequently in 2004, it was requested from the newly created European Food Safety Authority to perform a new evaluation of the mainly used phthalates on the basis of existing data. This paper summarizes evaluations of butylbenzylphthalate, dibutylphthalate, diethylhexylphthalate.
Antigen presenting cells and T cell interactions in the gastrointestinal tract
Authors: MacDonald Thomas T. , Voessenkamper Anna , Di Sabatino Antonio
Published: July 2009

Dendritic cells make up less than 1% of the cells in lymph nodes and tissues, but they are critical in initiating and directing T cell immune responses. In the gut, with exposure to myriad food and bacterial antigens, they probably control T cell unresponsiveness to food antigens and T cell hypersensitivity in disease situations. The need for the immune system to ‘know’ gut luminal antigens is demonstrated by the fact that dendritic cells send processes through the epithelium and directly sample antigens in the gut lumen. We present evidence that type I INF made by plasmacytoid dendritic cells may be important in coeliac disease.
Impact of food processing on the structural and allergenic properties of food allergens
Authors: Mills E. N. Clare , Sancho Ana I. , Rigby Neil M. , Jenkins John A. , Mackie Alan R.
Published: July 2009

This article reviews recent studies that address one of the major unanswered questions in food allergy research: what attributes of food or food proteins contribute to or enhance food allergenicity?
NMR‐based metabonomics reveals that plasma betaine increases upon intake of high‐fiber rye buns in hypercholesterolemic pigs
Authors: Bertram Hanne Christine , Malmendal Anders , Nielsen Niels Chr. , Straadt Ida Krestine , Larsen Torben , Bach Knudsen Knud Erik , Nygaard Lærke Helle
Published: July 2009

This study presents an NMR‐based metabonomic approach to explore the overall endogenous biochemical effects of a rye versus wheat‐based fiber‐rich diet in hypercholesterolemic pigs. The pigs were fed high‐fat, high‐cholesterol rye‐ (n = 9) or wheat‐ (n = 8) based buns with similar levels of dietary fiber for 9–10 wk. Fasting plasma samples were collected 2 days before and after 8 and 12 days on the experimental diets, while postprandial samples taken after 58–67 days, and 1H NMR spectra were acquired on these. Principal component analysis on the obtained NMR spectra demonstrated clear effects of diet on the plasma metabolite profile, and partial least squares regression discriminant analysis on the spectra revealed that the intensity of the spectral region at 3.29 ppm dominated the differentiation between the two diets, as the rye diet was associated with higher spectral intensity in this region. The 3.29 ppm signal is ascribed to N(CH3)3 protons in betaine, which may be an important contributor to the health promoting effects of rye.
Immunostimulatory properties of coffee mannans
Authors: Simões Joana , Madureira Pedro , Nunes Fernando M. , do Rosário Domingues Maria , Vilanova Manuel , Coimbra Manuel A.
Published: July 2009

Coffee infusion mannans are acetylated polysaccharides containing single Galp and Araf residues as side chains of a β‐(1 → 4)‐Manp backbone. These mannans are structurally similar to the bioactive acetylated mannans from Aloe vera (AV). In this study, acetylated mannans were obtained from two coffee infusions prepared from light and dark roasted beans. These samples were tested for their immunostimulatory activity and compared with an extract of AV mannan and with locust bean gum (LBG) galactomannans. The coffee samples, as well as the AV extract, stimulated murine B‐ and T‐lymphocytes, as evaluated by the in vitro expression of the surface lymphocyte activation marker CD69, more marked on B‐ than on T‐lymphocytes. In coffee samples, contrarily to the AV, no proliferative effect was noticed. LBG sample did not show any immunostimulatory activity. Because the material that remains in the residue of the hot water extraction was still very rich in mannans, a sequential extraction was performed and a main fraction was recovered with a 4 M NaOH solution. Because this material was insoluble in water, a partial acetylation was performed. These polysaccharides also showed immunostimulatory activity, opening the possibility of exploitation of coffee infusion and coffee residue as sources of bioactive polysaccharides.