bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Microwave‐Assisted Heck Reaction in Poly(ethylene glycol) for the Synthesis of Benzazepines
Authors: Declerck Valérie , Ribière Patrice , Nédellec Yannig , Allouchi Hassan , Martinez Jean , Lamaty Frédéric 
Published: November 2006

AbstractThe Heck reaction of alkylated 2‐(trimethylsilyl)ethanesulfonyl (SES)‐protected β‐amino esters provides benzazepines in good yields. Good selectivity towards cyclisation was obtained when the reaction was performed in PEG 3400 as the solvent under microwave activation. Cleavage of the SES group with HF provides the corresponding free benzazepine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Prepared to eat: how immediate affective and motivational responses to food cues are influenced by food deprivation
Authors: Seibt Beate , Häfner Michael , Deutsch Roland 
Published: November 2006

AbstractThree studies examined how food deprivation influences the immediate valence of food stimuli as well as spontaneous motivational tendencies toward them. We assumed that immediate reactions towards food stimuli should be tuned to the basic needs of the organism. In Study 1, the immediate valence of food names as a function of need state was assessed using an Implicit Association Test (IAT) in a quasi‐experimental design. Food deprivation led to a more positive immediate valence of food items. In Study 2, these results were replicated using the Extrinsic Affective Simon Task. In Study 3, immediate motivational reactions toward pictorial food stimuli were assessed. As hypothesized, approach reactions were facilitated for participants tested before as compared to after lunch, even in a sample with eating disorders. We thus conclude that the immediate valence of edible objects partially reflects regulation in the service of need fulfillment. Copyright © 2006 John Wiley & Sons, Ltd.
Development of Quantum Dots Modified Acetylcholinesterase Biosensor for the Detection of Trichlorfon
Authors: Li Xiao‐Hua , Xie Zonghong , Min Hong , Li Chenxin , Liu Meichuan , Xian Yuezhong , Jin Litong 
Published: November 2006

AbstractPoly (N‐vinyl‐2‐pyrrolidone) (PVP)‐capped CdS quantum dots (QCdS‐PVP) was synthesized with CdCl2 and Na2S in the presence of PVP. QCdS‐PVP has been used for the immobilization and stabilization of the acetylcholinesterase (AChE). The electrocatalytic activity of QCdS‐PVP leads to a greatly improved electrochemical detection of the enzymatically generated thiocholine product, and higher sensitivity and stability. The GCE/QCdS‐PVP/AChE biosensor was used for the detection of organophosphate pesticides (OPs), such as trichlorfon. The sensor performance, including pH and inhibition time, was optimized with respect to operating conditions. Under the optimal conditions, the biosensor was used to measure as low as 12 ppb trichlorfon with a 5‐min inhibition time.
Nucleophilic Addition of Thiaproline to Electrochemically Derived o‐Quinone, Application to the Sensitive Voltammetric Detection of Thiaproline
Authors: Shahrokhian Saeed , Amiri Mandana 
Published: November 2006

AbstractThe mechanism of electrochemical behavior of catechol in the presence of thiaproline is investigated by cyclic voltammetry, controlled‐potential coulometry and spectrophotometric tracing of the reaction coordinate. The results indicate that thiaproline participate in with an ECEC mechanism in a nucleophilic (Michael) addition to o‐quinone. Effect of pH of buffer solution on reaction pathway is studied and showed that addition of thiaproline to the o‐quinone is performed only in solutions with pHs higher than 5. These results indicate that the addition of thiaproline is occurred first from amine functional group. In the second step, the addition of carboxylate group of thiaproline to C‐5 of catechol results the final product with a lactone ring in its structure. Observation of two isosbestic point in absorption spectrum during the progress of the electrolysis together with the FT‐IR results for final product can be presented as evidence for two step addition of thiaproline to catechol. Final product, due to the electron donor property of thiaproline, more easily oxidized respect to the former catechol and as a result, a new redox couple is obtained for this compound in lower potentials. The easier anodic oxidation of addition product (relative to catechol) caused to an increase in anodic current for catechol, which is proportional to the thiaproline concentration. The differential pulse voltammetry (DPV) is applied as a sensitive voltammetric method for the detection of thiaproline. A linear range from 5×10−8 to 5×10−6 M with a detection limit of 1×10−8 M is resulted for thiaproline. With respect to the reversibility of the electrochemical reactions in the mechanism, and also more facile oxidation of the addition products, the square‐wave voltammetry is presented as a method with considerably more sensitivity for the detection of sub‐micromolar amounts of thiaproline. The advantageous properties of the voltammetric method for thiaproline detection lie in its excellent catalytic activity, sensitivity and simplicity.
Micromixer utilizing electrokinetic instability‐induced shedding effect
Authors: Tai Chang‐Hsien , Yang Ruey‐Jen , Huang Min‐Zhong , Liu Chia‐Wei , Tsai Chien‐Hsiung , Fu Lung‐Ming 
Published: November 2006

AbstractThis paper presents a T‐shaped micromixer featuring 45° parallelogram barriers (PBs) within the mixing channel. The presented device obtains a rapid mixing of two sample fluids with conductivity ratio of 10:1 (sample concentration:running buffer concentration) by means of the electrokinetic instability‐induced shedding effects which are produced when a direct current (DC) electric field of an appropriate intensity is applied. The presented device uses a single high‐voltage power source to simultaneously drive and mix the sample fluids. The effectiveness of the mixer is characterized experimentally as a function of the applied electrical field intensity and the extent to which the PBs obstruct the mixing channel. The experimental results indicate that the mixing performance reaches 91% at a cross‐section located 2.3 mm downstream of the T‐junction when the barriers obstruct 4/5 of the channel width and an electrical field of 300 V/cm is applied. The micromixing method presented in this study provides a simple low‐cost solution to mixing problems in lab‐on‐a‐chip systems.
Atmospheric molding of ionic copolymer MALDI‐TOF/MS arrays: A new tool for protein identification/profiling
Authors: Muck Alexander , Ibáñez Alfredo J. , Stauber Einar J. , Mansourova Madina , Svatoš Aleš 
Published: November 2006

AbstractAn atmospheric molding protocol has been used to prepare an ionic methacrylate‐based copolymer sample support chips for MALDI (pMALDI)‐MS by targeting selected groups of various monomers copolymerized during molding, namely, carboxy, sulfo, dimethylalkyamino, and trimethylalkylammonium groups. The new disposable array chips provide analyte‐oriented enhancement of protein adsorption to the modified substrates without requiring complicated surface coating or derivatization. The MALDI‐MS performance of the new ionic copolymer chips was evaluated for lysozyme, β‐lactoglobulin A, trypsinogen and carbonic anhydrase I using washing with solutions prepared in pH or ionic strength steps. On cationic chips, the proteins are washed out at pH lower than their pI values, and on anionic chips at pH higher than their pI values. The ability of the microfabricated pMALDI chip set to selectively adsorb different proteins from real samples and to significantly increase their MS‐signal was documented for the transmembrane photosystem I protein complex from the green alga Chlamydomonas reinhardtii. The proteins were almost exclusively adsorbed according to calculated pI values and grand average of hydropathy (GRAVY) indexes. The new disposable chips reduce manipulation times and increase measurement sensitivity for real‐world proteomic samples. The simple atmospheric molding procedure enables additional proteomic operations to be incorporated on disposable MALDI‐MS integrated platforms.
Polymorphisms in the thymidylate synthase promoter and the DNA repair genes XRCC1 and XPD in a Brazilian population
Authors: Canalle Renata , Andrade Vanessa da Silva S. , Scrideli Carlos A. , Queiroz Rosane G. de Paula , Tone Luiz G. 
Published: November 2006

AbstractPolymorphisms in genes responsible for maintaining genomic integrity are potential modifiers of disease risk. Since considerable interindividual and interethnic variation in DNA repair capacity has been associated with polymorphic alleles, we evaluated the frequency of the 2R/3R variants in the TS promoter, Arg194Trp and Arg399Gln in the XRCC1 gene, and Asp312Asn and Lys751Gln in the XPD gene in 364 healthy individuals from a Brazilian population separated by ethnicity (European ancestry and African ancestry). The genotypes were determined by PCR (TS) or by PCR‐RFLP (XRCC1 and XPD). The frequency of the TS 3R allele was 0.56 for whites and 0.51 for nonwhites. In the case of the XRCC1 MspI polymorphism, the allele frequencies were 0.09 for 194Trp in both nonwhites and whites and 0.27 and 0.28 for 399Gln in nonwhites and whites, respectively. For the XPD 312Asn allele, we found a frequency of 0.25 in white individuals, which was significantly different (P = 0.025) from that seen in nonwhites (0.15). Similarly, the 751Gln polymorphic allele of the XPD gene was significantly more frequent (P < 0.002) in whites (0.30) than in nonwhites (0.20). The genotype frequencies were within Hardy–Weinberg equilibrium. We concluded that the genotype and allele frequencies of XPD gene polymorphism differed between white and nonwhite Brazilians, and that the frequencies of the XPD 312Asn and XRCC1 399Gln alleles in this Brazilian population showed ethnic variability when compared with those observed in other populations. Environ. Mol. Mutagen., 2006. © 2006 Wiley‐Liss, Inc.
Skew‐symmetric distributions generated by the distribution function of the normal distribution
Authors: Gómez Héctor W. , Venegas Osvaldo , Bolfarine Heleno 
Published: November 2006

AbstractIn this paper we study a general family of skew‐symmetric distributions which are generated by the cumulative distribution of the normal distribution. For some distributions, moments are computed which allows computing asymmetry and kurtosis coefficients. It is shown that the range for asymmetry and kurtosis parameters is wider than for the family of models introduced by Nadarajah and Kotz (2003). For the skew‐t‐normal model, we discuss approaches for obtaining maximum likelihood estimators and derive the Fisher information matrix, discussing some of its properties and special cases. We report results of an application to a real data set related to nickel concentration in soil samples. Copyright © 2006 John Wiley & Sons, Ltd.
Carbon dioxide capture from flue gas by pressure swing adsorption at high temperature using a K‐promoted HTlc: Effects of mass transfer on the process performance
Authors: Reynolds Steven P. , Ebner Armin D. , Ritter James A. 
Published: November 2006

AbstractUsing hundreds (640) of simulations obtained from a cyclic adsorption process simulator, two heavy reflux (HR) pressure swing adsorption (PSA) cycles were analyzed at the periodic state for the capture and concentration of CO2 from flue gas at high temperature (575 K), using a K‐promoted hydrotalcite like compound (HTlc). Since the values of the adsorption (ka) and desorption (kd) mass transfer coefficients of CO2 in the K‐promoted HTlc were uncertain, this study focused only on the effects of ka and kd on the process performance. Both, a 5‐bed 5‐step stripping PSA cycle with light reflux (LR) and HR from LR purge and a 4‐bed 4‐step stripping PSA cycle with HR from countercurrent depressurization were studied using a vacuum swing cycle with the high pressure fixed at 137.9 kPa and the feed set at 15 vol % CO2, 75 vol % N2, and 10 vol % H2O. For the 5‐bed process, increasing both ka (= 0.0058 s−1) and kd (= 0.0006 s−1) by a factor of five increased both the CO2 purity and CO2 recovery, achieving a CO2 purity of nearly 90% at a CO2 recovery of 72% and feed throughput (θ) of 57.6 L STP/h/kg. Increasing ka and kd by a factor of ten further increased both the CO2 purity and CO2 recovery, achieving for the first time a CO2 purity greater than 90% at a CO2 recovery of 85% and θ of 57.6 L STP/h/kg. Making kd = ka (= 0.0058 s−1) resulted in a CO2 purity of 89% with a CO2 recovery of 72% at a θ of 57.6 L STP/h/kg; and increasing that value by a factor of five led to a CO2 purity of 91% at a high CO2 recovery of 88% and θ of 57.6 L STP/h/kg. These results suggested that the performance was desorption limited. For the 4‐bed process, when ka and kd were both increased by a factor of five, the CO2 purity increased to 98% at a θ of 201.7 L STP/h/kg, but the CO2 recovery decreased to 5%. Overall, it was proven that mass transfer effects were important to the performance of this high temperature CO2 recovery process, with higher but acceptable values of ka and kd leading to CO2 purities of greater than 90%, a needed limit for process viability. © 2006 American Institute of Chemical Engineers Environ Prog, 2006
Case studies of damage to 19‐storey irregular steel moment‐frame buildings under near‐source ground motion
Authors: Krishnan Swaminathan 
Published: November 2006

AbstractThis paper describes the three‐dimensional nonlinear analysis of six 19‐storey steel moment‐frame buildings, designed per the 1997 Uniform Building Code, under strong ground motion records from near‐source earthquakes with magnitudes in the range of 6.7–7.3. Three of these buildings possess a reentrant corner irregularity, while the remaining three possess a torsional plan irregularity. The records create drift demands of the order of 0.05 and plastic rotation demands of the order of 4–5% of a radian in the buildings with reentrant corners. These values point to performance at or near ‘Collapse Prevention’. Twisting in the torsionally sensitive buildings causes the plastic rotations on the moment frame on one face of the building (4–5% of a radian) to be as high as twice of that on the opposite face (2–3% of a radian). The asymmetric yield pattern implies a lower redundancy in the lateral force‐resisting system as the failure of the heavily loaded frame could result in a total loss of resistance to torsion. Copyright © 2006 John Wiley & Sons, Ltd.
A markup model for forecasting inflation for the euro area
Authors: Russell Bill , Banerjee Anindya 
Published: November 2006

AbstractWe develop a small model for forecasting inflation for the euro area using quarterly data over the period June 1973 to March 1999. The model is used to provide inflation forecasts from June 1999 to March 2002. We compare the forecasts from our model with those derived from six competing forecasting models, including autoregressions, vector autoregressions and Phillips‐curve based models. A considerable gain in forecasting performance is demonstrated using a relative root mean squared error criterion and the Diebold–Mariano test to make forecast comparisons.  Copyright © 2006 John Wiley & Sons, Ltd.
A hybrid forecasting approach for piece‐wise stationary time series
Authors: Yang Minxian , Bewley Ronald 
Published: November 2006

AbstractWe consider the problem of forecasting a stationary time series when there is an unknown mean break close to the forecast origin. Based on the intercept‐correction methods suggested by Clements and Hendry (1998) and Bewley (2003), a hybrid approach is introduced, where the break and break point are treated in a Bayesian fashion. The hyperparameters of the priors are determined by maximizing the marginal density of the data. The distributions of the proposed forecasts are derived. Different intercept‐correction methods are compared using simulation experiments. Our hybrid approach compares favorably with both the uncorrected and the intercept‐corrected forecasts.  Copyright © 2006 John Wiley & Sons, Ltd.
A stochastic proportional hazard model for the force of mortality
Authors: Lorenzo Emilia Di , Sibillo Marilena , Tessitore Gerarda 
Published: November 2006

AbstractIn order to avoid ‘frailty’ in deterministic assumptions concerning survival law, in this paper stochastic volatility in the force of mortality is considered. In particular, mortality rates are studied by means of a stochastic model of CIR type. A method for estimating its parameters is presented and an example of application, based on simulations of the process, is shown. Empirical results and comparison with a traditional model illustrate predictive performance and the flexibility of the model.  Copyright © 2006 John Wiley & Sons, Ltd.
Understanding and predicting sovereign debt rescheduling: a comparison of the areas under receiver operating characteristic curves
Authors: Rodriguez Arnulfo , Rodriguez Pedro N. 
Published: November 2006

AbstractThis paper extends the existing literature on empirical research in the field of sovereign debt. To the authors' knowledge, only one study in the area of sovereign debt has used a variety of statistical methodologies to test the reliability of their predictions and to compare their performance against one another. However, those comparisons across models have been made in terms of different probability cut‐off points and mean squared errors. Moreover, the issue of interpretability has not been addressed in terms of interactions among explanatory variables with their correspondent debt rescheduling threshold level. The areas under the Receiver Operating Characteristic (ROC) curves are used to compare the discrimination power of statistical models. This paper tests logit, MARS, tree‐based and neural network models. Analyses of the relative importance of variables and deviance were done. All of the models rank the previous payment history as the most important explanatory variable.  Copyright © 2006 John Wiley & Sons, Ltd.
Induction of senescence in MYCN amplified neuroblastoma cell lines by hydroxyurea
Authors: Narath R. , Ambros I. M. , Kowalska A. , Bozsaky E. , Boukamp P. , Ambros P. F. 
Published: November 2006

AbstractRecently, it was shown that MYCN amplified cells spontaneously expulse extrachromosomally amplified gene copies by micronuclei formation. Furthermore, it was shown that these cells lose their malignant phenotype and start to age. We tested whether it is possible to encourage neuroblastoma tumor cells to enter the senescence pathway by low concentrations of the micronuclei‐inducing drug hydroxyurea (HU). We studied the effect of HU on 12 neuroblastoma cell lines with extra‐ or intrachromosomally amplified MYCN copies and without amplification. Two extrachromosomally amplified neuroblastoma cell lines (with double minutes) were investigated in detail. Already after 3 weeks of HU treatment, the BrdU uptake dropped to 25% of the starting cells. After 4 weeks, enlarged and flattened cells (F‐cells) and increased granularity in the majority of cells were observed. A drastic reduction of the MYCN copy number—down to one copy per cell—associated with CD44 and MHCI upregulation in up to 100% of the HU treated neuroblastoma cells was found after 5–8 weeks. Telomere length was reduced to half the length within 8 weeks of HU treatment, and telomerase activity was not detectable at this time, while being strongly expressed at the beginning. All these features and the expression of senescence‐associated‐β‐galactosidase (SA‐β‐GAL) in up to 100% of the cells support the hypothesis that these cells entered the senescence pathway. Thus, low‐dose HU is a potent senescence elicitor for tumor cells with gene amplification, possibly representing an attractive additional strategy for treatment of this subset of tumors. © 2006 Wiley‐Liss, Inc.
PACAP/PAC1 autocrine system promotes proliferation and astrogenesis in neural progenitor cells
Authors: Nishimoto Mika , Furuta Akiko , Aoki Shunsuke , Kudo Yoshihisa , Miyakawa Hiroyoshi , Wada Keiji 
Published: November 2006

AbstractThe Pituitary adenylate cyclase‐activating peptide (PACAP) ligand/type 1 receptor (PAC1) system regulates neurogenesis and gliogenesis. It has been well established that the PACAP/PAC1 system induces differentiation of neural progenitor cells (NPCs) through the Gs‐mediated cAMP‐dependent signaling pathway. However, it is unknown whether this ligand/receptor system has a function in proliferation of NPCs. In this study, we identified that PACAP and PAC1 were highly expressed and co‐localized in NPCs of mouse cortex at embryonic day 14.5 (E14.5) and found that the PACAP/PAC1 system potentiated growth factor‐induced proliferation of mouse cortical NPCs at E14.5 via Gq‐, but not Gs‐, mediated PLC/IP3‐dependent signaling pathway in an autocrine manner. Moreover, PAC1 activation induced elongation of cellular processes and a stellate morphology in astrocytes that had the bromodeoxyuridine (BrdU)‐incorporating ability of NPCs. Consistent with this notion, we determined that the most BrdU positive NPCs differentiated to astrocytes through PAC1 signaling. These results suggest that the PACAP/PAC1 system may play a dual role in neural/glial progenitor cells not only differentiation but also proliferation in the cortical astrocyte lineage via Ca2+‐dependent signaling pathways through PAC1. © 2006 Wiley‐Liss, Inc.
Usefulness of MRI volumetric evaluation in patients with squamous cell cancer of the head and neck treated with neoadjuvant chemotherapy
Authors: Baghi Mehran , Mack Martin G. , Hambek Markus , Bisdas Sotirios , Muerthel Ramona , Wagenblast Jens , Gstoettner Wolfgang , Vogl Thomas , Knecht Rainald 
Published: November 2006

AbstractBackground.The purpose was to evaluate the efficacy of tumor volumetry on MRI as predictive of response to treatment with induction chemotherapy, comparing the results with endoscopy.Methods:Fifty patients with advanced squamous cell carcinoma of the head and neck (SSCHN) who underwent MRI volumetry before and after neoadjuvant chemotherapy consisting of docetaxel, cisplatin, and 5‐fluorouracil (TPF) were included in this study. The tumor volume was calculated by a slice‐by‐slice evaluation. With the standard software of a workstation, the area of the tumor was measured slice by slice using manual segmentation. To evaluate the efficacy of MRI volumetry, pretreatment volume was compared with pretreatment remission status as evaluated with endoscopy.Results.Forty‐five (90%) patients demonstrated a tumor downstaging after chemotherapy. Fourteen (28%) patients showed a complete histologic remission (CR), 31 (62%) patients showed a partial remission (PR). Pretreatment tumor volume was significantly different between patients whose tumor completely responded (CR) and those whose tumor did not completely respond or whose disease was stable or was progressive (p = .00023). We defined a threshold for the pretreatment tumor volume in patients with CR, which was equal to 29.71 cc.Conclusion.We propose that MRI tumor volume analyses can be a useful parameter to predict the response to neoadjuvant chemotherapy in SCCHN. © 2006 Wiley Periodicals, Inc. Head Neck, 2007