bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of the Oil on the Properties of Microemulsions as Reaction Media
Authors: García‐Río Luis , Godoy Ana , Rodríguez‐Dafonte Pedro 
Published: May 2006

AbstractThe influence of the nature of the continuous medium on various properties of a wide range of water‐in‐oil (w/o) microemulsions was examined. 1H NMR spectroscopy allowed to determine the properties of water in the studied systems and the way they are affected by the solvent to be elucidated. Changes in interfacial polarity were examined from the 13C NMR signals of the surfactant molecule sodium bis(2‐ethylhexyl)sulfosuccinate (AOT). Chemical shifts were found to vary with the water content of the microemulsion. The variation of the carbon chemical shift as a function of the water‐to‐surfactant concentration ratio (W) was used as an indirect measure of polarity changes at the microemulsion interface. The kinetic effects of the microemulsion composition on the solvolysis of anisoyl chloride were studied, and the reagent was found to react with water at the microemulsion interface alone. Based on both kinetic and NMR results, the solvolysis rate constants of anisoyl chloride decrease with increasing penetration of the oil into the interface. Also, the resonance signals for the water H atoms were found to change in parallel with the solvolysis rate constant for anisoyl chloride. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
New Solutions to the C‐12,13 Stereoproblem of Epothilones B and D; Synthesis of a 12,13‐Diol‐Acetonide Epothilone B Analog
Authors: Gaich Tanja , Karig Gunter , Martin Harry J. , Mulzer Johann 
Published: May 2006

AbstractNew approaches are described to the synthesis of epothilone B and a 12,13‐diol‐acetonide derivative. Specifically the (12Z) double bond is formed quantitatively by a silicon‐tethered ring‐closing metathesis (RCM) reaction with 85 % selectivity. Alternatively, a direct route to the 12,13‐epoxide by cyclization of a 12,13‐diol has been developed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Thiyl Radical Mediated Racemization of Benzylic Amines
Authors: Escoubet Stéphanie , Gastaldi Stéphane , Vanthuyne Nicolas , Gil Gérard , Siri Didier , Bertrand Michèle P. 
Published: May 2006

AbstractThiyl radical mediated reversible H abstraction from the stereogenic center α to the nitrogen atom is a mild method to racemize benzylic amines. Owing to the sensitivity of atom‐transfer reactions to enthalpic effects, a knowledge of both the S–H and the α‐C–H bond dissociation energies is fundamental to select the thiol that is appropriate to abstract the hydrogen atom from a given amine. In the absence of experimental data, theoretical calculations supply a useful predictive tool. The experiments described here are helpful in delineating the optimal conditions that have to be fulfilled for the racemization to proceed in a reasonable time in the presence of either a stoichiometric or a catalytic amount of thiol. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Rigid Bisphenanthrolines: Synthesis, Structure and Self‐Assembly at a Solid–Liquid Interface
Authors: Schmittel Michael , Kalsani Venkateshwarlu , Jäckel Frank , Rabe Jürgen P. , Bats Jan W. , Fenske Dieter 
Published: May 2006

AbstractSeveral rigid linear bisphenanthrolines with and without bulky groups at the bisimine sites were synthesized. For three representatives, the solid‐state structures were elucidated. Their potential for self‐assembled monolayers was explored by scanning tunneling microscopy (STM) at the solid–liquid interface, and the resulting architectures were found to be promising candidates for templating metal‐ion nanopatterns. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
New Metal‐Catalyzed Synthesis of Quinoline and Chromene Skeletons
Authors: Deagostino Annamaria , Farina Vittorio , Prandi Cristina , Zavattaro Chiara , Venturello Paolo 
Published: May 2006

AbstractAlkoxy‐functionalized butadienylboronic esters have been synthesized starting from α,β‐unsaturated acetals and cross‐coupled with both N‐protected and N‐unprotected 2‐bromo‐ and 2‐iodoaniline, and with 2‐iodophenol. In particular, N‐tosyl‐protected dienylanilines can be transformed under mild conditions into quinolines and quinolinones, in the presence of a PdII catalyst. Moreover, the cross‐coupling reaction between butadienylboronic esters and iodophenol directly affords chromenes that can be successively transformed into chromenones. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Interlaboratory study of a NACE method for the determination of R‐timolol content in S‐timolol maleate: Assessment of uncertainty
Authors: Marini Roland Djang'eing'a , Groom Carl , Doucet François R. , Hawari Jalal , Bitar Yaser , Holzgrabe Ulrike , Gotti Roberto , Schappler Julie , Rudaz Serge , Veuthey Jean‐Luc , Mol Roelof , Somsen Govert W. , de Jong Gerhardus J. , Ha Pham Thi Thanh , Zhang Jie , Van Schepdael Ann , Hoogmartens Jos , Briône Willy , Ceccato Attilio , Boulanger Bruno , Mangelings Debby , Vander Heyden Yvan , Van Ael Willy , Jimidar Ilias , Pedrini Matteo , Servais Anne‐Catherine , Fillet Marianne , Crommen Jacques , Rozet Eric , Hubert Philippe 
Published: May 2006

AbstractAnalyses of statistical variance were applied to evaluate the precision and practicality of a CD‐based NACE assay for R‐timolol after enantiomeric separation of R‐ and S‐timolol. Data were collected in an interlaboratory study by 11 participating laboratories located in Europe and North America. General qualitative method performance was examined using suitability descriptors (i.e. resolution, selectivity, migration times and S/N), while precision was determined by quantification of variances in the determination of R‐timolol at four different impurity levels in S‐timolol maleate samples. The interlaboratory trials were designed in accordance with the ISO guideline 5725‐2. This allowed estimating for each sample, the different variances, i.e. between‐laboratory (s2Laboratories), between‐day (s2Days) and between‐replicate (s2Replicates). The variances of repeatability (s2r) and reproducibility (s2R) were then calculated. The estimated uncertainty, derived from the precision estimates, seems to be concentration‐dependent above a given threshold. This example of R‐timolol illustrates how a laboratory can evaluate uncertainty in general.
Capillary electrophoresis for the analysis of glycoprotein pharmaceuticals
Authors: Kamoda Satoru , Kakehi Kazuaki 
Published: May 2006

AbstractCarbohydrate chains in glycoprotein pharmaceuticals play important roles for the expression of their biological activities, but the structure and compositions of carbohydrate chains are dependent on the conditions for their production. Therefore, evaluation of the carbohydrate chains is quite important for productive process development, characterization of product for approval application, and routine quality control. The oligosaccharides themselves have complex structure including blanching and various glycosidic linkages, and oligosaccharides in one glycoprotein pharmaceutical generally have high heterogeneity, and characterization of oligosaccharide moiety in glycoprotein has been a challenging target. In these situations, CE has been realized as a powerful tool for oligosaccharide analysis due to its high resolution and automatic operating system. This review focuses on the application of CE to the glycoform analysis of glycoproteins and profiling of the N‐linked glycans released from glycoprotein pharmaceuticals. Current applications for structure analysis using CE‐MSn technique and glycan profiling method for therapeutic antibody are also described.
Capillary electrophoresis contributions to the hydromorphone metabolism in man
Authors: Baldacci Andrea , Thormann Wolfgang 
Published: May 2006

AbstractCE‐ESI multistage IT‐MS (CE‐MSn, n ≤ 4) and computer simulation of fragmentation are demonstrated to be effective tools to detect and identify phase I and phase II metabolites of hydromorphone (HMOR) in human urine. Using the same CE conditions as previously developed for the analysis of urinary oxycodone and its metabolites, HMOR and its phase I metabolites produced by N‐demethylation, 6‐keto‐reduction and N‐oxidation and phase II conjugates of HMOR and its metabolites formed with glucuronic acid, glucose, and sulfuric acid could be detected in urine samples of a patient that were collected during a pharmacotherapy episode with daily ingestion of 48 mg of HMOR chloride. The CE‐MSn data obtained with the HMOR standard, synthesized hydromorphol and hydromorphone‐N‐oxide, and CYP3A4 in vitro produced norhydromorphone were employed to identify the metabolites. This approach led to the identification of previously unknown HMOR metabolites, including HMOR‐3O‐glucide and various N‐oxides, structures for which no standard compounds or mass spectra library data were available. Furthermore, the separation of α‐ and β‐hydromorphol, the stereoisomers of 6‐keto‐reduced HMOR, was achieved by CE in the presence of the single isomer heptakis(2,3‐diacetyl‐6‐sulfato)‐β‐CD. The obtained data indicate that the urinary excretion of α‐hydromorphol is larger than that of β‐hydromorphol.
Temperature effects on the mass flow rate in the SBI and similar heat‐release rate test equipment
Authors: Sette Bart J. G. , Theuns Erwin , Merci Bart , Vandevelde Paul 
Published: May 2006

AbstractIn various medium‐to‐large‐scale fire test equipments like the ISO room corner test (RC), and more recently, the single burning item test (SBI) the mass flow rate measurement of the combustion gases plays a key role in the determination of the heat‐release rate and smoke‐production rate.With the knowledge of the velocity profile and the temperature of the flow, the mass flow rate is obtained by measuring the velocity on the axis of the duct. This is done by means of a bi‐directional probe based on the pitot principle.However, due to the variation of the mean temperature and the temperature gradient in any cross section of the duct, introduced by ever changing combustion gas temperatures, the velocity nor the density profile are constant in time. This paper examines the resulting uncertainty on the mass flow rate. Copyright © 2006 John Wiley & Sons, Ltd.
Hydrogen sulphide regulates calcium homeostasis in microglial cells
Authors: Lee Shiau Wei , Hu Ye‐Shi , Hu Li‐Fang , Lu Qing , Dawe Gavin S. , Moore Philip K. , Wong Peter T.‐H. , Bian Jin‐Song 
Published: May 2006

AbstractHydrogen sulphide (H2S), which is produced endogenously from L‐cysteine in mammalian tissues, has been suggested to function as a neuromodulator in the brain. However, the role of H2S in microglial cells is unclear. In this study, the effect of exogenous and endogenous H2S on intracellular calcium homeostasis was investigated in primary cultured microglial cells. Sodium hydrosulphide (NaHS), a H2S donor, caused a concentration‐dependent (0.1–0.5 mM) increase in intracellular calcium concentration ([Ca2+]i). This effect was significantly attenuated in the presence of a calcium‐free extracellular solution, Gd3+ (100 μM), a nonselective Ca2+ channel blocker, or thapsigargin (2 μM), an inhibitor of the sarcoplasmic/endoplasmic reticulum Ca2+‐ATPase. These observations suggest that the increase in [Ca2+]i in response to H2S involves both calcium influx across the plasma membrane and calcium release from intracellular stores. The H2S‐induced calcium elevation is partly attenuated by H‐89, a selective cAMP‐dependent protein kinase (PKA) inhibitor, but not by U73122, a phospholipase C (PLC) inhibitor, and chelerythrine, a selective protein kinase C (PKC) inhibitor, suggesting the involvement of cAMP/PKA, but not PLC/PKC/phosphoinositol‐3,4,5‐inositol (IP3) pathway. Using RT‐PCR, only cystathionine γ‐lyase (CSE), a H2S producing enzyme, was detected in primary cultures of microglia. Lowering endogenous H2S level with, D,L‐propargylglycine and β‐cyano‐L‐alanine, two CSE inhibitors, significantly decreased [Ca2+]i, suggesting that endogenous H2S may have a positive tonic influence on [Ca2+]i homeostasis. These findings support the possibility that H2S may serve as a neuromodulator to facilitate signaling between neurons and microglial cells. © 2006 Wiley‐Liss, Inc.
Tolbutamide reduces glioma cell proliferation by increasing connexin43, which promotes the up‐regulation of p21 and p27 and subsequent changes in retinoblastoma phosphorylation
Authors: Sánchez‐Alvarez Rosa , Paíno Teresa , Herrero‐González Sandra , Medina José M. , Tabernero Arantxa 
Published: May 2006

AbstractOur previous work has shown that tolbutamide increases gap junctional permeability in poorly coupled C6 glioma cells and that this effect is similar and additive to that found with dbcAMP, a well‐known activator of gap junctional communication. Furthermore, the increase in gap junctional communication promoted by tolbutamide or dbcAMP is concurrent with the inhibition of proliferation of C6 glioma cells. In the present work, we show that tolbutamide and dbcAMP increase the synthesis of the tumor suppressor protein Cx43 and that they decrease the level of Ki‐67, a protein expressed when cells are proliferating. These effects were accompanied by a reduction in the phosphorylation of pRb, mainly on Ser‐795, a residue critical for the control of cell proliferation. The decrease in the phosphorylation of pRb is not likely to be mediated by a reduction in the levels of D‐type cyclins, since instead of decreasing the expression of cyclins, D1 and D3 increased slightly after treatment with tolbutamide or dbcAMP. However, the Cdk inhibitors p21 and p27 were up‐regulated after treatment with tolbutamide and dbcAMP, suggesting that they would be involved in the decrease in pRb phosphorylation. When Cx43 was silenced by siRNA, neither tolbutamide nor dbcAMP were able to up‐regulate p21 and consequently to reduce glioma cell proliferation, as judged by Ki‐67 expression. In conclusion, tolbutamide and dbcAMP inhibit C6‐glioma cell proliferation by increasing Cx43, which correlates with a reduction in pRb phosphorylation due to the up‐regulation of the Cdk inhibitors p21 and p27. © 2006 Wiley‐Liss, Inc.
Analysis of intersubject variability in activation: An application to the incidental episodic retrieval during recognition test
Authors: Sugiura Motoaki , Friston Karl J. , Willmes Klaus , Shah Nadim J. , Zilles Karl , Fink Gereon R. 
Published: May 2006

AbstractSince the brain may engage different neuronal systems for a single behavioral goal, activation may show intersubject variability expressed in the systematic recruitment of multiple distinct networks. We apply a principal component analysis (PCA) to activation over task conditions and subjects to reveal cortical networks that may underlie this intersubject variability. Normal subjects were presented with novel meaningless objects, which appeared in personally familiar or unfamiliar places. During a subsequent, event‐related functional MRI (fMRI) experiment, each subject was presented with learned or novel objects in isolation and performed a learned/novel judgment. Recollection of places was not essential for the task, and may exhibit large intersubject variations. The right posterodorsal posterior cingulate cortex (pPCC) and left retrosplenial cortex, whose involvement in place‐recognition has been previously established, were selected as regions of interest for the PCA. Neural responses to objects associated with familiar relative to unfamiliar places in pPCC, but not in the retrosplenial cortex, were negatively correlated with task‐related activation (common over all objects) in the right anterolateral prefrontal cortex and the left intraparietal sulcus. The latter areas have been implicated previously in cognitive control and object recognition, respectively. These results suggest right prefrontal control over neural processes both in the left parietal cortex, related to object‐recognition (enhancement), and pPCC, related to nonessential recollection of place‐memory (suppression), but not in the retrosplenial cortex, related to the sense of familiarity. This analysis revealed an important aspect of functional anatomy that was not detectable using a conventional analysis of average activations. Hum. Brain Mapp, 2007. © 2006 Wiley‐Liss, Inc.
Volitional control of attention and brain activation in dual task performance
Authors: Newman Sharlene D. , Keller Timothy A. , Just Marcel Adam 
Published: May 2006

AbstractThis study used functional MRI (fMRI) to examine the neural effects of willfully allocating one's attention to one of two ongoing tasks. In a dual task paradigm, participants were instructed to focus either on auditory sentence comprehension, mental rotation, or both. One of the major findings is that the distribution of brain activation was amenable to strategic control, such that the amount of activation per task was systematically related to the attention‐dividing instructions. The activation in language processing regions was lower when attending to mental rotation than when attending to the sentences, and the activation in visuospatial processing regions was lower when attending to sentences than when attending to mental rotations. Additionally, the activation was found to be underadditive, with the dual‐task condition eliciting less activation than the sum of the attend sentence and attend rotation conditions. We also observed a laterality shift across conditions within language‐processing regions, with the attend sentence condition showing bilateral activation, while the dual task condition showed a left hemispheric dominance. This shift suggests multiple language‐processing modes and may explain the underadditivity in activation observed in the current and previous studies. Hum. Brain Mapp, 2007. © 2006 Wiley‐Liss, Inc.
Unified structural equation modeling approach for the analysis of multisubject, multivariate functional MRI data
Authors: Kim Jieun , Zhu Wei , Chang Linda , Bentler Peter M. , Ernst Thomas 
Published: May 2006

AbstractThe ultimate goal of brain connectivity studies is to propose, test, modify, and compare certain directional brain pathways. Path analysis or structural equation modeling (SEM) is an ideal statistical method for such studies. In this work, we propose a two‐stage unified SEM plus GLM (General Linear Model) approach for the analysis of multisubject, multivariate functional magnetic resonance imaging (fMRI) time series data with subject‐level covariates. In Stage 1, we analyze the fMRI multivariate time series for each subject individually via a unified SEM model by combining longitudinal pathways represented by a multivariate autoregressive (MAR) model, and contemporaneous pathways represented by a conventional SEM. In Stage 2, the resulting subject‐level path coefficients are merged with subject‐level covariates such as gender, age, IQ, etc., to examine the impact of these covariates on effective connectivity via a GLM. Our approach is exemplified via the analysis of an fMRI visual attention experiment. Furthermore, the significant path network from the unified SEM analysis is compared to that from a conventional SEM analysis without incorporating the longitudinal information as well as that from a Dynamic Causal Modeling (DCM) approach. Hum. Brain Mapp, 2007. © 2006 Wiley‐Liss, Inc.
Sustainable groundwater management in Kinmen Island
Authors: Liu Chen‐Wuing , Lin Chun‐Nan , Jang Cheng‐Shin , Chen Chan‐Po , Chang Jen‐Fu , Fan Chen‐Chun , Lou Kuo‐Hiang 
Published: May 2006

AbstractKinmen county is located in the southwest of Fujen province, China. It comprises Kinmen, Leiyu and other small islands. Its total area is around 150 km2. Kinmen is the largest island, and 95% of the population resides there. The average annual precipitation is 1072 mm. Rainfall is concentrated in a 5 month period from mid‐April to mid‐September. Water resources are limited relative to demand. Eastern Kinmen utilizes surface water, whereas western Kinmen uses groundwater. Moreover, the Kinmen sorghum liquor is brewed using the native groundwater in the west of the island. MODFLOW‐96 was used to simulate the groundwater distribution and determine the annual amount of infiltration, pumping, and boundary inflow and outflow. Additionally, a groundwater management index was adopted to evaluate the status of groundwater level change, thus allowing local government officials to adjust the pumping scheme dynamically. To achieve a sustainable groundwater supply in Kinmen, an integrated groundwater extraction plan was proposed. This plan includes enhancing the infiltration by using treated wastewater from the east of the island, monitoring the groundwater level change, adjusting the groundwater pumping scheme, and constructing seawater desalination plants. If the hostile confrontation between Taiwan and mainland China is resolved, then the water supply through an undersea pipeline from Sharmen, China, to Kinmen can be another potential source of water for Kinmen in the future. Copyright © 2006 John Wiley & Sons, Ltd.
Evaluating fine sediment mobilization and storage in a gravel‐bed river using controlled reservoir releases
Authors: Petticrew E. L. , Krein A. , Walling D. E. 
Published: May 2006

AbstractTwo controlled flow events were generated by releasing water from a reservoir into the Olewiger Bach, located near Trier, Germany. This controlled release of near bank‐full flows allowed an investigation of the fine sediment (<63 µm) mobilized from channel storage. Both a winter (November) and a summer (June) release event were generated, each having very different antecedent flow conditions. The characteristics of the release hydrographs and the associated sediment transport indicated a reverse hysteresis with more mass, but smaller grain sizes, moving on the falling limb. Fine sediment stored to a depth of 10 cm in the gravels decreased following the release events, indicating the dynamic nature and importance of channel‐stored sediments as source materials during high flow events. Sediment traps, filled with clean natural gravel, were buried in riffles before the release of the reservoir water and the total mass of fine sediment collected by the traps was measured following the events. Twice the mass of fine sediment was retained by the gravel traps compared with the natural gravels, which may be due to their altered porosity. Although the amount of fine sediment collected by the traps was not significantly related to measures of gravel structure, it was found to be significantly correlated to measures of local flow velocity and Froude number. A portion of the traps were fitted with lids to restrict surface exchange of water and sediment. These collected the highest amounts of event‐mobilized sediments, indicating that inter‐gravel lateral flows, not just surface infiltration of sediments, are important in replenishing and redistributing the channel‐stored fines. These findings regarding the magnitude and direction of fine sediment movement in gravel beds are significant in both a geomorphic and a biological context. Copyright © 2006 John Wiley & Sons, Ltd.