bluuebunny/crossref_metadata_2025 huggingface dataset:
Sequence variation in the 3′‐untranslated region of the dopamine transporter gene and attention‐deficit hyperactivity disorder (ADHD)
Authors: Feng Yu , Wigg Karen G. , Makkar Rohit , Ickowicz Abel , Pathare Tejaswee , Tannock Rosemary , Roberts Wendy , Malone Molly , Kennedy James L. , Schachar Russell , Barr Cathy L.
Published: August 2005

The dopamine transporter gene (DAT1) has been reported to be associated with attention‐deficit hyperactivity disorder (ADHD) in a number of studies [Cook et al. (1995): Am J Human Genet 56(4):9993–998; Gill et al. (1997): Mol Psychiatry 2(4):311–313; Waldman et al. (1998): Am J Human Genet 63(6):1767–1776; Barr et al. (2001): Biol Psychiatry 49(4):333–339; Curran et al. (2001): Mol Psychiatry 6(4):425–428; Chen et al. (2003): Mol Psychiatry 8(4):393–396]. Specifically, the 10‐repeat allele of the 40‐bp variable number of tandem repeats (VNTR) polymorphism located in the 3′ untranslated region (UTR) of the gene has been found to be associated with ADHD. There is evidence from in vitro studies indicating that variability in the repeat number, and sequence variation in the 3′‐UTR of the DAT1 gene may influence the level of the dopamine transporter protein [Fuke et al. (2001): Pharmacogenomics J 1(2):152–156; Miller and Madras (2002): Mol Psychiatry 7(1):44–55]. In this study, we investigated whether DNA variation in the DAT1 3′UTR contributed to ADHD by genotyping DNA variants around the VNTR region in a sample of 178 ADHD families. These included a MspI polymorphism (rs27072), a DraI DNA change (T/C) reported to influence DAT1 expression levels, and a BstUI polymorphism (rs3863145) in addition to the VNTR. We also screened the VNTR region by direct resequencing to determine if there was sequence variation within the repeat units that could account for the association. Our results indicate that DAT1 is associated with ADHD in our sample but not with alleles of the VNTR polymorphism. We did not find any variation in the sequence for either the 10‐ or 9‐repeat alleles in the probands screened nor did we observe the reported DraI (T/C) variation. Our results therefore refute the possibility of the reported DraI variation or alleles of the VNTR as the functional variants contributing to the disorder. © 2005 Wiley‐Liss, Inc.
Analysis of the SREBF2 gene as a genetic risk factor for vascular dementia
Authors: Kim Younyoung , Nam Yu Jin , Lee Chaeyoung
Published: August 2005

A case‐control study was performed to examine the association between vascular dementia and the polymorphisms of the human gene encoding sterol regulatory element binding protein‐2 (SREBF2) that regulates cholesterol metabolism. The 16 genetic variants of SREBF2 were identified in 24 Koreans, and 5 out of 16 variants were genotyped in 207 vascular dementia patients and 207 control subjects. Significant association with vascular dementia was shown in 34995G/T with the GT genotype (odds ratio [OR] = 1.57; 95% CI = 1.04–2.37; P < 0.05) and the GG genotype (OR = 0.65; 95% CI = 0.44–0.96; P < 0.05). The CGC, the most common haplotype combined with three SNPs, 24489C/T, 34995G/T, and 68891C/T, was associated with the disease (OR = 0.72; 95% CI = 0.53–0.97; P < 0.05), and the individuals with the CGC might be less susceptible to vascular dementia than those carrying any haplotype including at least one minor allele. This study implied that the variants of SREBF2 might be genetic factors involved in the pathogenesis of vascular dementia. © 2005 Wiley‐Liss, Inc.
Association studies of transforming growth factor‐β1 and Alzheimer's disease
Authors: Dickson M.R. , Perry R.T. , Wiener H. , Go R.C.P.
Published: August 2005

Substantial laboratory evidence suggests Transforming Growth Factor‐β1 (TGFB1) is linked to Alzheimer's Disease (AD) pathology. The purpose of the study was to estimate the genetic association of TGFB1 with AD while controlling for apolipoprotein E4 allele (APOE4) status, the only well‐established genetic risk factor for AD. Two study populations were genotyped for the TGFB1−509 and +869 single nucleotide polymorphisms (SNPs) that have been associated with TGFB1 levels. Constituting these populations were 203 families from the NIMH AD Genetic Initiative with at least two affected siblings and a normal sibling, and a population of 126 African‐American (AA) AD cases versus 93 age matched controls. Results from family‐based analyses showed a significant association between the TGFB1 −509 SNP and AD for the entire set of 203 families (P = 0.007), and a subset of these families without a homozygous APOE4 family member (P = 0.026). Results from family‐based analyses on the TGFB1 +869 SNP were not significant in the 203 families. While associations for the main effects of the TGFB1 +869 and −509 SNP with AD in the AA case‐control study were also not significant, results did indicate that TGFB1 may function as an effect modifier of APOE4 risk. Specifically, the odds of AD associated with having at least one APOE4 allele increased in an additive fashion with one or two copies of the higher producer allele when stratified by TGFB1 −509 genotype and by TGFB1 +869 genotype. Results support a role for TGFB1 in AD pathogenesis. © 2005 Wiley‐Liss, Inc.
Short‐term thermal endurance evaluation of thermoplastic polyesters by isothermal and nonisothermal thermogravimetric analysis
Authors: Saccani Andrea , Motori Antonio , Montanari Gian Carlo
Published: August 2005

Thermogravimetric analysis, carried out in a pure oxygen flow both in isothermal and constant‐rate heating conditions, is proposed as an analytical technique for the estimation of thermal endurance parameters (the temperature index and halving interval) of polymeric materials, according to the short‐term procedure suggested by the IEC 61026 Standard. This technique was applied for the determination of the activation energy of the degradation process of three thermoplastic polyesters used in the electrical and packaging industries: poly(ethylene terephthalate), poly(buthylene terephtalate), and poly(ethylene naphthalate). The results obtained are presented and compared with results previously derived by the long‐term conventional procedure described in IEC 60216; satisfactory agreement of the thermal endurance parameters was generally observed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 968–973, 2005
Modification of cellulose fibers with functionalized silanes: Effect of the fiber treatment on the mechanical performances of cellulose–thermoset composites
Authors: Abdelmouleh Makki , Boufi Sami , Belgacem Mohamed Naceur , Dufresne Alain , Gandini Alessandro
Published: August 2005

Unsaturated polyester and epoxy resin matrices were filled with silane‐treated cellulose fibers and the ensuing composites were tested in terms of mechanical properties before and after accelerated aging consisting of their immersion into water. The coupling agents used were γ‐aminopropyltriethoxysilane (APS), γ‐methacrylopropyltrimethoxysilane (MPS), hexadecytrimethoxysilane, and γ‐mercaptopropyltrimethoxysilane (MRPS) and those containing reactive functions capable of reacting at one end with the fibers and at the other with the matrix, namely, APS, MPS, and MRPS, were more efficient in improving the mechanical properties of the composites. The immersion into water induced a drastic loss of mechanical properties of the materials. The water uptake of the composites was also studied and showed that the silane treatment was poorly efficient in preventing cellulose from water absorption. The fracture surfaces were inspected by scanning electron microscopy, which confirmed the quality of the interface. These observations were in agreement with the results obtained from the dynamic mechanical characterization. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 974–984, 2005
Synthesize and characterization of styrene‐N‐phenyl maleimide/montmorillonite nanocomposites prepared through emulsion polymerization
Authors: Liu Guodong , Zhang Liucheng , Li Zongjian , Qu Xiongwei
Published: August 2005

Composites of organomodified (OMMT) and pristine montmorillonite (MMT) intercalated by styrene‐N‐phenyl maleimide (PMI) copolymer were prepared by emulsion intercalative polymerization. X‐ray diffraction (XRD) and transmission electron microscopy results show that the dispersability of clay in the matrix was greatly improved by the incorporation of polar moiety PMI. The dispersability of OMMT in the matrix is better than MMT. XRD patterns of the extracted nanocomposites showed that d001 of the clay are much larger than that of the original OMMT and MMT, which indicates that the interaction of copolymer with the clay layers was greatly improved by incorporation with polar monomer PMI. The thermal property of the composites was greatly improved by the intercalation with clay. The DSC results showed that the glass transition of the composites became inconspicuous, which indicated that the movement of the polymer segment was extremely confined by the clay layer. The consistency factor of the melts of the composites increased monotonically with a decreasing flow index showing stronger shear thinning property of the composites. The rheological activity energy of the composites decreased more than that of the pure copolymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1010–1015, 2005
Preparation of N‐butyl chitosan and study of its physical and biological properties
Authors: Li Jing , Gong Yandao , Zhao Nanming , Zhang Xiufang
Published: August 2005

N‐Butyl chitosans with different substitution degrees were prepared by solid–liquid heterogeneous reaction, varying the ratio of chitosan to butyl bromide. FTIR and free amino percentage analysis confirmed that the substitution reaction occurred primarily on NH2 moieties. X‐ray diffraction results of the chitosan derivatives showed that the hydrogen bonds were weakened by the incorporation of pendant alkyl. N‐Butyl chitosan films exhibited a higher elastic modulus, a lower percentage of elongation at break, decreased equilibrium swelling ratios, and slightly increased surface hydrophobicity compared to chitosan film. The results of ELISA indicated that the adsorption amount of fibronectin on butyl chitosan films was much higher than on chitosan film, which was maybe due to the rearrangement of hydrophilicity/hydrophobicity after modification. The MTT assay suggested that the viability and proliferation of osteoblast cells on N‐butyl chitosan films were higher than that on chitosan film. These results suggest that N‐butyl chitosan is a promising candidate biomaterial for bone regeneration. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1016–1024, 2005
The usage of linseed oil‐based polyurethanes as a rheological modifier
Authors: Yılmaz Orçun , Baranak Murat , Güner F. Seniha , Erciyes A. Tuncer
Published: August 2005

Some oil‐based urethanes (urethane oils) were prepared from linseed oil, glycerol, and two types of diisocyanates, hexamethyle diisocyanate (HMDI) and 4,4′‐ diphenylmethane diisocyanate (MDI). These urethane oils were used as a rheological modifier in solvent‐based coatings. For this purpose the mixture prepared from urethane oil and alkyd resin (AR‐UO) was investigated in view of flow properties. Time dependence of AR‐UO was investigated by using the hysteresis loop method. None of the samples showed thixotropic flow behavior. The flow type was decided after calculation of the ratio of viscosity at low shear rate to viscosity at high shear rate. The results showed that HMDI‐based samples had the smallest viscosity ratio and increasing the amount of aromatic structure caused increasing shear thinning behavior. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1032–1035, 2005
Swelling behaviors of a three‐component copolymer (starch graft sodium acrylate and 2‐acrylamido‐2‐methyl‐propanosulfonic acid) synthesized by microwave polymerization
Authors: Xu K. , Zhang W. D. , Yue Y. M. , Wang P. X.
Published: August 2005

A superabsorbent of starch, 2‐acrylamido‐2‐methyl‐propanosulfonic acid (AMPS), and sodium acrylate was synthesized by microwave irradiation, and the effect of AMPS on the performance of the polymer was investigated. The best mass fraction of the three components was determined (starch/acrylic acid/AMPS = 2 : 5 : 3). The structure of the polymer was characterized by Fourier transform infrared, 13C cross‐polarization/magic‐angle spinning NMR, and scanning electron microscopy, and the morphology of the surface of the sample was studied. The results showed that the morphology of the polymer was changed to some extent under microwave irradiation, and the swelling rate of the polymer synthesized by microwave polymerization was faster than the swelling rate of a polymer synthesized by a traditional method. The best absorbent capacities of the product in distilled water and a 0.9% sodium chloride solution were 450 and 53 g/g, respectively. Meanwhile, the introduction of AMPS to a superabsorbent resin was an effective method for improving the performance of the polymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1050–1054, 2005
Image querying by image professionals
Authors: Jörgensen Corinne , Jörgensen Peter
Published: August 2005

This article reports the analysis of two samples of search logs from a commercial image provider over a 1‐month period. The study analyzes image searches and queries, user query modification strategies, and user browsing and downloading of results. Unique term searches are less frequent than earlier research has shown; descriptive and thematic queries are more common. Boolean searching, although heavily employed, appears to be ineffective and leads to query modifications. Although there was a large amount of query modification (61.7% of queries across the two samples), the tactics overall do not appear to be carefully thought out and seem to be largely experimental. Given the willingness to modify queries but the inability to do so in an effective way, more support for query modification may be beneficial.
Market segmentation for customer satisfaction studiesviaa new latent structure multidimensional scaling model
Authors: Wu Jianan , DeSarbo Wayne S.
Published: August 2005

It has been well documented in the marketing literature that customer satisfaction is critical to any businesses' success. However, it is far less clear as on how marketers comprehend customer differences in customer satisfaction evaluations, and leverage such understanding in forming their marketing strategies. Only recently have researchers begun to explore the notion of individual or segment differences in the formation of overall satisfaction judgments.

To extend the exploration of unobserved customer heterogeneity in customer satisfaction studies with multiple attributes, we propose a latent structure multidimensional scaling (MDS) model to visually depict unobserved customer heterogeneity with respect to the theoretical components of customer satisfaction judgments. Our model is developed on the basis of the well‐established expectancy–disconfirmation theory of customer satisfaction. We describe the proposed MDS model and discuss the technical aspects of the model structure and maximum likelihood estimation. Copyright © 2005 John Wiley & Sons, Ltd.
Current issues and a ‘wish list’ for conjoint analysis
Authors: Bradlow Eric T.
Published: August 2005

Conjoint analysis is one of the most celebrated tools in Marketing, and its widespread use (not just widespread publication history) has been one of the greatest success stories in Marketing/Business of the academic and practitioner interface. In this article, I provide a wish‐list, of sorts, summarizing current cutting‐edge research that is trying to fill some holes, and other issues that I ‘wish’ were trying to be filled.

By literally using a list‐like statement, current answer, and wish‐list format for this article, I hope to provide guidance to both academics and practitioners as to the areas for future important conjoint research. Copyright © 2005 John Wiley & Sons, Ltd.
The value of simple models in new product forecasting and customer‐base analysis
Authors: Fader Peter S. , Hardie Bruce G. S.
Published: August 2005

In this paper, we develop the idea of a ‘simple model’—defined as one that a good business student can build and implement on his/her notebook PC using readily available software. We explore how such models have the potential to bridge the gap between what marketing academics create and what marketing managers seek in a model. We provide specific examples from the areas of new product sales forecasting and customer‐base analysis, using spreadsheet‐based models that provide good forecasts and insights about actual buyer behaviour. Copyright © 2005 John Wiley & Sons, Ltd.
O2 and Vacancy Diffusion on Rutile(110): Pathways and Electronic Properties
Authors: Tilocca Antonio , Selloni Annabella
Published: August 2005

The binding structures and diffusion pathways of molecular oxygen on a defective TiO2(110) surface are studied by means of a recently developed first‐principles string molecular dynamics approach. A variety of molecular and dissociated O2 adsorption states are identified and the kinetics of their interconversion is analyzed. These results, as well as calculations of the electronic properties and of scanning tunneling microscopy (STM) images, are used to discuss recent experimental observations of the interactions between surface oxygen vacancies and the adsorbed oxygen molecule.
Isobaric–Isothermal Monte Carlo Simulations from First Principles: Application to Liquid Water at Ambient Conditions
Authors: McGrath Matthew J. , Siepmann J. Ilja , Kuo I‐Feng W. , Mundy Christopher J. , VandeVondele Joost , Hutter Jürg , Mohamed Fawzi , Krack Matthias
Published: August 2005

A series of first‐principles Monte Carlo simulations in the isobaric–isothermal ensemble were carried out for liquid water at ambient conditions (T=298 K and p=1 atm). The Becke–Lee–Yang–Parr (BLYP) exchange and correlation energy functionals and norm‐conserving Goedecker–Teter–Hutter (GTH) pseudopotentials were employed with the CP2 K simulation package to examine systems consisting of 64 water molecules. The fluctuations in the system volume encountered in simulations in the isobaric–isothermal ensemble require a reconsideration of the suitability of the typical charge‐density cutoff and the regular grid‐generation method previously used for the computation of the electrostatic energy in first‐principles simulations in the microcanonical or canonical ensembles. In particular, it is noted that a much higher cutoff is needed and that the most computationally efficient method of creating grids can result in poor simulations. Analysis of the simulation trajectories using a very large charge‐density cutoff at 1200 Ry and four different grid‐generation methods point to a significantly underestimated liquid density of about 0.8 g cm−3 resulting in a somewhat understructured liquid (with a value of about 2.7 for the height of the first peak in the oxygen–oxygen radial distribution function) for BLYP‐GTH water at ambient conditions. In addition, a simulation using a charge‐density cutoff at 280 Ry yields a higher density of 0.9 g cm−3, showing the sensitivity of the simulation outcome to this parameter.
Car–Parrinello Molecular Dynamics Study of DCl Hydrate Crystals
Authors: Sillanpää Atte , Laasonen Kari
Published: August 2005

Three DCl hydrates have been studied using Car–Parrinello (CP) molecular dynamics. The structural results at low temperatures (T<350 K) agree with experiment and previously published CP results. The monohydrate has been shown to be built from D3O+ and Cl− ions. The dihydrate is built exclusively from D5O2+ and Cl− ions. The trihydrate consists of D2O, D5O2+, and Cl− ions. Thus, the DCl hydrates are excellent systems for studying ideal D3O+ and D5O2+ ions. The data from these ideal structures can be compared to high‐concentration acid–liquid simulations. [ClD⋅⋅⋅Cl]− ions were detected at amorphous and fluid conditions after melting the di‐ and trihydrate crystals. The experimentally observed spectral continuum can be explained by combining the Eigen and Zundel spectra, and interpolating between the shared deuterium frequencies of the latter and the stretching band of the former.
Improvement of detection specificity of Plasmodium‐infected murine erythrocytes by flow cytometry using autofluorescence and YOYO‐1
Authors: Jiménez‐Díaz María Belén , Rullas Joaquín , Mulet Teresa , Fernández Laura , Bravo Carmen , Gargallo‐Viola Domingo , Angulo‐Barturen Iñigo
Published: August 2005

Background

Microscopic analysis of blood smears is currently the most frequently used method to measure parasitemias in experiments of drug efficacy in murine models of malaria. However, it is subjective and labour intensive, which preclude its utilization in large‐scale evaluation programs. Flow cytometry is an alternative method, but due to the limited specificity achieved with the currently available techniques, it has not been widely used in murine models of malaria during preclinical evaluation. We describe a new flow cytometric method based on the differences of autofluorescence and DNA content measured after staining with YOYO‐1 that are observed in infected erythrocytes compared with noninfected erythrocytes.

Methods

Samples of blood from Plasmodium yoelii–infected animals were fixed with glutaraldehyde, incubated with RNAase, and stained with YOYO‐1 in 96‐well plate format. After acquisition, erythrocytes gated in logarithmic side/scatter plots were analyzed in bidimensional FL‐2/YOYO‐1 plots in comparison with unidimensional YOYO‐1 analysis.

Results

The infected erythrocytes showed a characteristic pattern of staining different from that of noninfected erythrocytes. In routine evaluation, the limit of sensitivity was 0.01% and the measurements of parasitemia were linear at parasitemias above 0.1%. Interestingly, using this approach, infected reticulocytes could be differentiated from infected normocytes.

Conclusions

The method described is robust, increases the specificity and sensitivity of detection in routine testing, and is especially well suited for detection of low parasitemias in murine models of malaria. © 2005 Wiley‐Liss, Inc.
Smart 3D‐fish: Automation of distance analysis in nuclei of interphase cells by image processing
Authors: Gué Michael , Messaoudi Cédric , Sun Jian Sheng , Boudier Thomas
Published: August 2005

Background

Detection of fluorescent probes by fluorescence in situ hybridization in cells with preserved three‐dimensional nuclear structures (3D‐FISH) is useful for studying the organization of chromatin and localization of genes in interphase nuclei. Fast and reliable measurements of the relative positioning of fluorescent spots specific to subchromosomal regions and genes would improve understanding of cell structure and function.

Methods

3D‐FISH protocol, confocal microscopy, and digital image analysis were used.

Results

New software (Smart 3D‐FISH) has been developed to automate the process of spot segmentation and distance measurements in images from 3D‐FISH experiments. It can handle any number of fluorescent spots and incorporate images of 4′,6‐diamino‐2‐phenylindole counterstained nuclei to measure the relative positioning of spot loci in the nucleus and inter‐spot distance. Results from a pilot experiment using Smart 3D‐FISH on ENL, MLL, and AF4 genes in two lymphoblastic cell lines were satisfactory and consistent with data published in the literature.

Conclusion

Smart 3D‐FISH should greatly facilitate image processing and analysis of 3D‐FISH images by providing a useful tool to overcome the laborious task of image segmentation based on user‐defined parameters and decrease subjectivity in data analysis. It is available as a set of plugins for ImageJ software. © 2005 Wiley‐Liss, Inc.
Small‐volume rapid‐mix device for subsecond kinetic analysis in flow cytometry
Authors: Wu Yang , Zwartz Gordon , Lopez Gabriel P. , Sklar Larry A. , Buranda Tione
Published: August 2005

Background

Rapid‐mix flow cytometry has emerged as a powerful tool for mechanistic analysis of ligand binding, cell response, and molecular assembly. Although progress has come from improving sample delivery capabilities, little attention has been paid to the volumetric requirements associated with precious biological reagents.

Methods

By using programmable syringes, valves, and other fluidic components, we created a modular, precisely regulated rapid‐mix device for the delivery of small‐volume samples to the flow cytometer. The device was tested using a bead‐based assay in which the binding kinetics between native biotin and fluorescein biotin‐bearing beads were characterized.

Results

Bead suspensions and reagents paired in 35‐ to 45‐μl aliquots were efficiently mixed by the device and delivered to the flow cytometer. Kinetic data associated with the fluorescein biotin beads were analyzed and used to calibrate the performance characteristics of the device in terms of sample delivery and mixing efficiency.

Conclusion

The rapid‐mix device is capable of detecting subsecond kinetics of biological reactions using microliter volume of samples. Dimensions of the device have been minimized, and the quantitative aspects of sample delivery and analysis have been optimized. Further, the modular design has been optimized for adaptation to a variety of experimental protocols. © 2005 Wiley‐Liss, Inc.
Synthesis, Electronic Characterisation and Significant Second‐Order Non‐Linear Optical Responses of meso‐Tetraphenylporphyrins and Their ZnII Complexes Carrying a Push or Pull Group in the β Pyrrolic Position
Authors: Annoni Elisabetta , Pizzotti Maddalena , Ugo Renato , Quici Silvio , Morotti Tamara , Bruschi Maurizio , Mussini Patrizia
Published: August 2005

This work describes the synthesis and characterisation by electronic absorption spectroscopy, cyclic voltammetry and by a solvatochromic investigation of meso‐tetraphenylporphyrins and their ZnII complexes substituted at the β pyrrolic position by a pseudo‐linear, π‐delocalised organic linker carrying either an electron‐withdrawing (pull) or electron‐donating (push) group. The second‐order NLO response of these push‐pull porphyrinic chromophores has been investigated by the EFISH technique working with a non‐resonant incident wavelength of 1.907 µ;m. The porphyrin ring substituted at the β pyrrolic position by an electron‐acceptor π‐system behaves as a significant donor group, comparable to a ferrocenyl group or to a phthalocyanine. Unexpectedly, the porphyrin ring substituted at the β pyrrolic position with an electron‐donor π‐system shows a larger and significant second‐order NLO response. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
The Design and Synthesis of New Steroidal Compounds as Potential Mimics of Taxoids
Authors: Roussi Fanny , Ngo Quoc Anh , Thoret Sylviane , Guéritte Françoise , Guénard Daniel
Published: August 2005

Eight new steroidal compounds bearing the phenylisoserine and benzoate side‐chains of docetaxel were synthesised as potential mimics of antitumour taxoids. They were readily obtained either from cholic acid or from 4‐androstene‐3,17‐dione by a reductive Tsuji–Trost/reduction one‐pot reaction. Two compounds showed an unexpected inhibitory activity of tubulin assembly. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
NMR Study of the (Z)‐Phenylhydrazones of 5‐Alkyl‐ and 5‐Aryl‐3‐benzoyl‐1,2,4‐oxadiazoles: Support for the Interpretation of Kinetic Results on the Rearrangement of 1,2,4‐Oxadiazoles to 1,2,3‐Triazoles
Authors: Mezzina Elisabetta , Spinelli Domenico , Lamartina Liliana , D’Anna Francesca , Frenna Vincenzo , Macaluso Gabriella
Published: August 2005

An analysis of the 1H, 13C, and 15N NMR substituent chemical shifts (SCSs) of the title compounds in CDCl3 solution has been carried out by using the SCSs of other classes of compounds (arenes, methyl esters or amides), Hammett substituent constants or kinetic data. The results obtained provide information concerning the ground‐state electronic distribution of the compounds examined. The results relevant to the carbon and nitrogen atoms of the 1,2,4‐oxadiazole ring can be considered of special interest, as the effects of the substituents on the chemical shifts of N‐4 and C‐5 appear in line with kinetic results collected in the study of the rearrangement (Boulton–Katritzky reaction) of the title compounds into the relevant 1,2,3‐triazoles, thereby strongly supporting the importance of the leaving‐group ability of the N‐4/C‐5/O‐1 system. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
C‐3′‐Cyclopropanated Taxol Analogs: Synthesis, Bioassay and Biostructural Analysis
Authors: Liu Changhui , Tamm Markus , Nötzel Marcus W. , Rauch Karsten , de Meijere Armin , Schilling Jennifer K. , Lakdawala Ami , Snyder James P. , Bane Susan L. , Shanker Natasha , Ravindra Rudravajhala , Kingston David G. I.
Published: August 2005

Ten taxoids with a cyclopropanated side chain were synthesized by coupling a spirocyclopropanated oxazoline‐5‐carboxylic acid with 7‐(triethylsilyl)baccatin III, followed by hydrolytic ring opening and benzoyl migration. The absolute configuration of the 2′‐position was determined by NMR analysis of the corresponding Mosher esters. These paclitaxel analogs were active in A2780 mammalian and PC‐3 prostate cancer cell lines, and also in a tubulin‐assembly assay, but all the analogs were less active than paclitaxel itself. To probe the basis for the uniform potency reduction shown by the cyclopropanated taxoid series, we have examined the conformational properties of compound 3b alone by molecular mechanics and in complex with tubulin by molecular dynamics. In addition, we have performed an NMR/NAMFIS conformer deconvolution analysis for compound 3b. Both modeling and NAMFIS approaches provide a satisfying understanding of the biological behavior of the series of cyclopropanated taxoids and provide further, though indirect, support for the T‐form as characteristic of taxoids bound to β‐tubulin. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
N‐Confused Porphine
Authors: Morimoto Tatsuki , Taniguchi Shozo , Osuka Atsuhiro , Furuta Hiroyuki
Published: August 2005

A skeleton of N‐confused porphyrin (NC‐porphine) has been synthesized for the first time, through a [3+1] coupling reaction. A completely planar inner 3H tautomeric form was found in the crystals, and the molecular packing shows a sandwich herringbone structure similar to that of normal porphine, whilst some of the spectroscopic properties demonstrate systematic substituent effects by the meso‐phenyl groups on the N‐confused porphyrin. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Separation and determination of toxic pyrrolizidine alkaloids in traditional Chinese herbal medicines by micellar electrokinetic chromatography with organic modifier
Authors: Yu Lijun , Xu Yan , Feng Huatao , Li Sam Fong Yau
Published: August 2005

A simple and rapid micellar electrokinetic chromatography (MEKC) method was developed for the separation and determination of four toxic pyrrolizidine alkaloids (PAs) (senkirkine, senecionine, retrorsine, and seneciphylline) in two traditional Chinese herbal medicines (Qian liguang and Kuan donghua). Separation was performed in the running buffer consisting of 20 mM borate, 30 mM SDS, and 20% methanol at pH 9.1. With the optimized separation conditions, four PAs were separated in 17 min by a single run. The calibration curves showed good linearity with correlation efficiencies (R2) between 0.9940 and 0.9988. RSDs in migration time and peak area were 0.31, 0.40, 0.39, 0.48% and 3.28, 3.48, 4.16, 3.42% for senkirkine, senecionine, retrorsine, and seneciphylline, respectively. Limits of detection (S/N = 3) varied from 1.19 to 2.70 μg/mL. The proposed method was applied to determine the PAs extracted from Chinese herbal medicines (Qian liguang and Kuan donghua). PA of senkirkine in Kuan donghua was detected and the amount was found to be 79.1 μg/g. The results obtained indicate that the proposed MEKC method could potentially become an effective alternative tool for qualification control and quantitative analysis of herbal medicines in pharmaceutical industry.
Analysis of neutral nitromusks in incenses by capillary electrophoresis in organic solvents and gas chromatography‐mass spectrometry
Authors: Gotti Roberto , Fiori Jessica , Mancini Francesca , Cavrini Vanni
Published: August 2005

Nitromusks used as fragrances in a variety of personal‐care products, cleansers, and domestic deodorants, including incense sticks, are neutral nitro aromatic compounds; some of these have been reported as photosensitizers. In this work, their analysis was performed by capillary electrophoresis (CE) in a methanol‐based background electrolyte (BGE). In particular, a 10 mM solution of citric acid in methanol was used; under these conditions the strong suppression of the electroosmotic flow favored the use of negatively charged surfactants as additives for the anodic migration of the studied analytes. To this end, sodium taurodeoxycholate (TDC) was supplemented at high concentration (190 mM) to the organic background electrolyte (BGE), showing strong indication of the ability to give micelle‐like aggregates. Since nitromusks are characterized by the presence of a nitroaromatic ring with low charge density, their association with TDC aggregates can be ascribed to donor–acceptor interactions. Separation of musk xylene, musk ketone, and the banned musk moskene and musk ambrette was obtained under full nonaqueous BGE; the addition of relatively small water percentages (15% v/v) was found to be useful in improving the separation of pairs of adjacent peaks. Under optimized conditions (190 mM sodium TDC in methanol–water, 85–15 v/v containing citric acid 10 mM) the system was applied to the analysis of nitromusks in incense sticks extracted with methanol. The results were compared with those obtained by the analysis of the same samples using gas chromatography with mass detector. The expected different selectivity of separation obtained using the two techniques can be useful in the unambiguous determination of the analytes; furthermore, a substantial accord of the preliminary quantitative results achieved with the two methods was assumed as the confirmation of the potential reliability of CE performed with high percentage of organic solvent.
Distributed current estimates using cortical orientation constraints
Authors: Lin Fa‐Hsuan , Belliveau John W. , Dale Anders M. , Hämäläinen Matti S.
Published: August 2005

Distributed source models of magnetoencephalographic (MEG) and electroencephalographic (EEG) data employ dense distributions of current sources in a volume or on a surface. Previously, anatomical magnetic resonance imaging (MRI) data have been used to constrain locations and orientations based on cortical geometry extracted from anatomical MRI data. We extended this approach by first calculating cortical patch statistics (CPS), which for each patch corresponding to a current source location on the cortex comprise the area of the patch, the average normal direction, and the average deviation of the surface normal from its average. The patch areas were then incorporated in the forward model to yield estimates of the surface current density instead of dipole amplitudes at the current locations. The surface normal data were employed in a loose orientation constraint (LOC), which allows some variation of the current direction from the average normal. We employed this approach both in the ℓ2 minimum‐norm estimates (MNE) and in the more focal ℓ1 minimum‐norm solutions, the minimum‐current estimate (MCE). Simulations in auditory and somatosensory areas with current dipoles and 10‐ or 20‐mm diameter cortical patches as test sources showed that applying the LOC can increase localization accuracy. We also applied the method to in vivo auditory and somatosensory data. Hum Brain Mapp, 2005. © 2005 Wiley‐Liss, Inc.
Bilateral activation of the prefrontal cortex after strategic semantic cognitive training
Authors: Miotto Eliane C. , Savage Cary R. , Evans Jonathan J. , Wilson Barbara A. , Martins M.G.M. , Iaki Suzan , Amaro Edson
Published: August 2005

The prefrontal cortex (PFC) has been implicated in the ability to apply semantic organizational strategies during verbal encoding and episodic learning. However, there has been no direct evidence demonstrating which specific areas in the PFC are engaged after cognitive training using semantic organizational strategies in healthy adult human subjects. In this study, we investigated the effects of semantic strategic training on brain activity and changes in behavioral performance, after cognitive training, using functional MRI (fMRI). There was a significant activation in bilateral dorsolateral prefrontal (DLPF) and orbitofrontal (OFC) areas after cognitive training. These results demonstrate the engagement of bilateral DLPF and OFC cortex during strategic memory processes, particularly when mobilization and effort of effective use of strategies are required. The functional adaptations observed here may also shed light on some of the processes underlying recovery with cognitive rehabilitation in patient populations with brain injury. Hum Brain Mapp, 2005. © 2005 Wiley‐Liss, Inc.
Proteomic analysis of protein adsorption: Serum amyloid P adsorbs to materials and promotes leukocyte adhesion
Authors: Kim Jin‐Ku , Scott Evan A. , Elbert Donald L.
Published: August 2005

Serum and plasma protein adsorption on materials was analyzed using gel electrophoresis and ion trap mass spectrometry. Following incubation of polypropylene, polyethylene terephthalate (PET), or polydimethylsiloxane (PDMS) with 5% serum for longer than 4 h, we found unexpectedly high amounts of the pentraxin serum amyloid P. It was previously shown that serum amyloid P is constitutively expressed in humans, functions as an opsonin, and interacts with the Fcγ receptors on leukocytes. We demonstrate that serum amyloid P adsorbed to tissue culture polystyrene, PDMS, and PET promotes the adhesion of granulocytes and monocytes in the presence of calcium. The methods developed for these studies may be useful for the large‐scale study of protein adsorption and do not rely on radiolabeling or the availability of antibodies. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Excretion of resorption products from bioactive glass implanted in rabbit muscle
Authors: Lai William , Garino Jonathan , Flaitz Catherine , Ducheyne Paul
Published: August 2005

Bioactive glass granules were implanted in the paraspinal muscle of rabbits to determine the pathway of the silicon released from bioactive glass in vivo. We traced and quantified the silicon released by obtaining 24‐h urine and blood samples for up to 6 months after implantation. Furthermore, local muscle tissue as well as the following organs were resected for chemical and histopathological analyses: brain, heart, kidney, liver, lung, lymph nodes, spleen, and thymus. The urinary silicon of the group with implanted granules was significantly higher than in the sham‐operated, control group. The average excretion rate was 2.4 mg/day, and as such, 100% of the implanted silicon was excreted in 19 weeks. No elevated concentrations of silicon were found at the implant sites or in the other organs at sacrifice, that is, 24 weeks. The histological appearance of all organs was normal throughout. The concentrations of silicon measured in the urine were well below saturation and because no significant increase in silicon was found in any organ, including kidney, the increased silicon excretion rate was within the physiological capacity of rabbits. Therefore, it can be concluded that the resorbed silica gel is harmlessly excreted in soluble form through the urine. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
A joint study based on the electron localization function and catastrophe theory of the chameleonic and centauric models for the Cope rearrangement of 1,5‐hexadiene and its cyano derivatives
Authors: Polo Victor , Andrés Juan
Published: August 2005

A novel interpretation of the chameleonic and centauric models for the Cope rearrangements of 1,5‐hexadiene (A) and different cyano derivatives (B: 2,5‐dicyano, C: 1,3,4,6‐tetracyano, and D: 1,3,5‐tricyano) is presented by using the topological analysis of the electron localization function (ELF) and Thom's catastrophe theory (CT) on the reaction paths calculated at the B3LYP/6‐31G(d,p) level. The progress of the reaction is monitorized by the changes of the ELF structural stability domains (SSD), each being change controlled by a turning point derived from CT. The reaction mechanism of the parent reaction A is characterized by nine ELF SSDs. All processes occur in the vicinity of the transition structure and corresponding to a concerted formation/breaking of C1C6 and C3C4 bonds, respectively, together with an accumulation of charge density onto C2 and C5 atoms. Reaction B presents the same number of ELF SSDs as A, but a different order appears; the presence of 2,5‐dicyano substituents favors the formation of C1C6 bonds over the breaking of C3C4 bond process, changing the reaction mechanism from a concerted towards a stepwise, via a cyclohexane biradical intermediate. On the other side, reaction C presents the same type of turning points but two ELF SSD less than A or B; there is an enhancement of the C3C4 bond breaking process at an earlier stage of the reaction by delocalizing the electrons from the C3C4 bond among the cyano groups. In the case of competitive effects of cyano subsituents on each moiety, as it is for reaction D, seven different ELF SSDs have been identified separated by eight turning points (two of them occur simultaneously). Both processes, formation/breaking of C1C6 and C3C4 bonds, are slightly favored with respect to the parent reaction (A), and the TS presents mixed electronic features of both B and C. The employed methodology provides theoretical support for the centauric nature (half‐allyl, half‐radical) for the TS of D. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1427–1437, 2005
Mechanical Aspects of Clathrin Cage Formation
Authors: Nossal Ralph
Published: August 2005

The principal component of the coats of endocytic vesicles involved in the receptor‐mediated uptake of materials from the surfaces of eucaryotic cells is a protein known as clathrin. Clathrin normally appears as a three‐legged trimer joined at a common hub (a ‘triskelion’) which, under appropriate conditions, co‐assembles with other triskelia to form variably‐sized polyhedra (‘cages’, or ‘baskets’) that contain pentagonal and hexagonal faces. The size distribution of the cages can be described by a simple energetic model which contains, as a parameter, the flexural rigidity, EI, of the edges (struts) of the baskets. By comparing the values of EI thus obtained with similar quantities determined by analyzing electron micrographs of isolated triskelia (A. J. Jin, R. Nossal, Biophys. J. 2000, 78, 1183), we infer that one role of clathrin‐associated proteins known as ‘assembly proteins’ is to link the intertwined legs of neighboring triskelia to prevent slippage when the cages are stressed.
Time‐Dependent Permeabilities of Hydrophobic, pH‐Sensitive Hydrogels Exposed to pH Gradients
Authors: Dhanarajan Anish P. , Siegel Ronald A.
Published: August 2005

pH‐dependent changes in permeability to glucose of a poly(N‐isopropylacrylamide‐co‐methacrylic acid) hydrogel membrane were measured with the membrane clamped between two cells. The donor cell was maintained at pH 7.0 and the receptor cell was subjected to a set of ramps in pH. Starting with the membrane in a state of high permeability to glucose, a ramp of decreasing pH led ultimately to shutoff of glucose flux. With passage of time at a fixed, low pH, however, permeability was restored to an intermediate value. Upon ramping pH back to its initial value, the initial permeability was restored. Based on light microscopy, the nonstationary permeability behavior is attributed to lateral stress‐induced morphological changes that occur in a collapsed “skin” formed on the side of the membrane facing the acidic donor solution.
Electric and Magnetic Field‐Structured Smart Composites
Authors: Varga Zsolt , Filipcsei Genovéva , Szilágyi András , Zrínyi Miklós
Published: August 2005

The combination of polymers with nanomaterials displays novel and often enhanced properties compared to the traditional materials. They can open up possibilities for new technological applications. The electric‐ and magnetic‐ field‐sensitive elastomers represent a new type of composites consisting of small particles, usually from nanometer range to micron range, dispersed in high elastic polymeric matrix. Coupling of electric and/or magnetic fields with elastic properties leads to a number of striking phenomena that are exhibited in response to impressed external fields.

The ability of such materials to change their size and mechanical properties in a reversible manner has inherent interest, if for no other reason than the uniqueness having giant elastic response to polarization. The giant deformational effect, high elasticity, anisotropic properties, and quick response to either electric or magnetic fields open new opportunities for using such materials for various applications. Since electric and magnetic fields are convenient stimuli from the point of signal control, it is of great importance to develop and study such flexible, smart polymeric systems.
Internal Tension: A Novel Hypothesis Concerning the Mechanical Properties of the Vitreous Humor
Authors: Nickerson Charles S. , Karageozian Hampar L. , Park John , Kornfield Julia A.
Published: August 2005

The vitreous humor is a soft viscoelastic gel composed of a complex network of biomolecules (primarily collagen and polyhyaluronic acid, “hyaluronan”). While extensive progress has been made in identifying the components of the vitreous, lack of sufficient experimental methods has hampered previous efforts to quantitatively define its mechanical properties. To address this issue, we have developed a novel “cleat” tool geometry for dynamic shear rheometry. Using this geometry we find that the shear moduli of vitreous decline by roughly a factor of five to steady‐state values within an hour after removal from the eye. Steady‐state values (Porcine: G′ = 2.6 ± 0.9 Pa, and G″ = 0.65 ± 0.41 Pa, n = 9; Bovine: G′ = 6.5 ± 2.0 Pa, and G″ = 2.0 ± 0.6 Pa, n = 17) are significantly larger than previously reported. The decrease in modulus also correlates with a decrease in mass (65 ± 11 %, n = 8) that occurs spontaneously after the vitreous is extracted. Rheological findings, taken in combination with biochemical analyses suggest that hyaluronan, a ubiquitous polyelectrolyte in connective tissue, contributes to vitreous stiffness by inducing tension in the network in vivo.
Fluorescence Correlation Spectroscopy Study of Probe Diffusion in Poly(vinyl alcohol) Solutions and Gels
Authors: Michelman‐Ribeiro Ariel , Boukari Hacène , Nossal Ralph , Horkay Ferenc
Published: August 2005

In this study, we demonstrate how the diffusion of probe particles in aqueous poly(vinyl alcohol) (PVA) solutions and gels is affected by: (i) the presence of cross‐links, (ii) the cross‐link density, (iii) the polymer concentration. We apply fluorescence correlation spectroscopy (FCS) to measure the diffusion time of a rhodamine‐based fluorescent particle (TAMRA) and TAMRA‐labeled dextran in PVA solutions and gels prepared at various polymer concentrations (1% to 8.6% w/v) and cross‐link densities (1/400 to 1/50 cross‐link monomers per PVA monomers). The measurements indicate that the probe particles are slowed down with increasing polymer concentration and with increasing cross‐link density. Also, FCS can detect differences in the diffusion times measured in “fresh” and “aged” PVA solutions. We find that FCS provides a quantitative measure of network inhomogeneities.