bluuebunny/crossref_metadata_2025 huggingface dataset:
Absorbency and adsorption of poly(acrylic acid‐co‐acrylamide) hydrogel
Authors: Xie Jianjun , Liu Xinrong , Liang Jifu
Published: July 2007

Poly(acrylic acid‐co‐acrylamide) (PAAAM) hydrogels have been prepared from partly neutralized acrylic acid (AA) and acrylamide (AM) by solution polymerization, and their absorbency and adsorption in both CuCl2 and FeCl3 solutions have been investigated. PAAAM hydrogels and their complexes with Cu2+ or Fe3+ have been characterized by FTIR. The absorbency of PAAAM in both CuCl2 and FeCl3 solutions increases initially and then decreases as the absorbing time increases. The adsorption of PAAAM in both CuCl2 and FeCl3 solutions can be described by the pseudo‐second order chemisorption kinetics proposed by Ho and McKay, and the equilibrium uptake of Cu2+ on PAAAM can well be fit with the Langmuir adsorption isotherm. However, the equilibrium uptake of Fe3+ on PAAAM increases as the initial Fe3+ concentration increases for Fe3+ concentration smaller than 5.625 × 10−3 mol/L, and then decreases with Fe3+ concentration. The largest uptakes for Cu2+ and Fe3+ are 247 and 173 mg/g, respectively. The results also show that the uptake of Cu2+ and Fe3+ on PAAAM increases remarkably when pH of the solution is changed from 2.3 to 4.2 and from 1.0 and 2.1, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Surface dyeability of cotton and nylon fabrics coated with a novel porous silk fibroin/silica nanohybrid
Authors: Li Wenbin , Zou Lingli , Zhou Xingpin , Zhang Baohua , Wang Xiaqin , Chen Dajun
Published: July 2007

A new and facile approach of surface dyeing was developed for cotton and nylon fabrics coated with a novel porous silk fibroin (SF)/silica (SiO2) nanohybrid. Actually, dyeing of the fabrics occurred in the very thin nanohybrid layers exclusively, while the main body of the fabrics remained intact on the whole. With the assistance of the large surface areas of the porous nanohybrid, dye uptake of the coated cotton fabrics dyed with Acid Red GSF or Disperse Cation Red SD‐GRL was enhanced substantially compared with that of the uncoated fabrics as a control. Moreover, dye uptake increased with the SF content in the hybrid, indicating that the SF moiety played a significant role for the surface dyeing process. Color fastness to water of both the dyestuffs was much higher for the coated cotton fabrics compared with that of the uncoated ones. Similar results were obtained for the nanohybrid coated nylon fabrics dyed with Disperse Cation Red SD‐GRL as those of the coated cotton fabrics. However, no increase was observed for dye uptake of the coated nylon fabrics dyed with Acid Red GSF owing to saturation of the dyestuff attached on the controlled uncoated nylon fabrics, which concealed the contribution of the nanohybrid layer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Poly(lactic acid)/polystyrene bioblends characterized by thermogravimetric analysis, differential scanning calorimetry, and photoacoustic infrared spectroscopy
Authors: Mohamed Abdellatif , Gordon Sherald H. , Biresaw Girma
Published: July 2007

Bioblends are composites of at least one biodegradable polymer with nonbiodegradable polymer. Successful development of bioblends requires that the biodegradable polymers be compatible with other component polymers. Compatibility can be assessed by evaluating the intermolecular interactions between the component polymers. In this work, the interaction in binary bioblends comprising biodegradable poly(lactic acid) (PLA) and polystyrene (PS) was investigated using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier transform infrared photoacoustic spectroscopy (FTIR‐PAS). The TGA studies indicated that incorporation of PLA in PS resulted in thermal destabilization of PS. The DSC studies showed that some parameters favored partial miscibility of PS in PLA, while others favored immiscibility, such as the existence of two glass transitions. The FTIR‐PAS spectra revealed the presence of intermolecular n–π interactions between PLA and PS and indicated that the degree of interaction was dependent on the concentrations of the polymers in the bioblends. FTIR‐PAS results computed via differential spectral deconvolution were consistent with, and therefore support, the results of TGA and DSC analyses of PLA/PS bioblends. The degradation kinetics, used to determine the degradation mechanism, revealed a two‐ or three‐step mechanism. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Electrochemical deposition of polycarbazole thin films onto tin oxide coated glass: Physicochemical and optoelectronic characterizations
Authors: Yapi Abé S. , Bernède J. C. , Ugalde L. , Trégouët Y. , del Valle M. A.
Published: July 2007

Polycarbazole (PCz) thin films have been synthesized by electrochemistry. The influence of the deposition technique, potentiostatic or potentiodynamic, on the properties of the PCz films has been studied using the deposition time and the potential maximum as parameters. The PCz films have been characterized by thermal analysis, X‐ray photoelectron spectroscopy (XPS), near ultra violet, visible and infra red absorption, photoluminescence (PL) measurements, scanning electron microscopy and microprobe analysis. Whatever the technique used, polymerized carbazole (Cz) films are deposited onto tin oxide coated glass. It is shown that potential maximum of 1400 mV or more induces some Cz nucleus destruction with NN bonds formation. It is also shown by different techniques such as XPS, visible and IR absorption, microanalysis, PL, that the oxido–reduction reaction is reversible. Moreover, after dedoping treatment, nearly pure PCz film can be obtained, which allows obtaining PCz depoped films with good PL properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
New functional bicomponent fibers with core/sheath‐configuration using poly(phenylene sulfide) and poly(ethylene terephthalate)
Authors: Houis Stéphanie , Schmid Manfred , Lübben Jörn
Published: July 2007

Bicomponent fibers using the high‐performance polymer poly(phenylene sulfide) (PPS) together with poly(ethylene terephthalate) (PET) were melt‐spun. Both possibilities of using PPS, either as core or as sheath material, were realized to provide special functionalities like improved thermobonding capability, flame retardancy, or chemical resistance. Parameters that guarantee stable processing of PPS and PET during coaxial extrusion with different core/sheath volume ratios were explored. Microscopic studies of the cross‐sections showed holes and cavities, which were formed at the interface between PPS and PET. Possible mechanisms for cavity formation were evaluated. Results of thermal and mechanical characterization by means of TGA, DSC, and tensile testing revealed a strong influence of the processing parameters, namely draw ratio and core/sheath volume ratio, on the crystallization and the tensile strength of the drawn fibers. By changing the core/sheath volume ratio from 2 to 0.5 in the PPS/PET fiber, the crystallinity of the PET‐component was switched from 10 to 50%, whereas the crystallinity of the PPS dropped from 68 to 7%. It was determined that bicomponent fibers can exceed the strength of monocomponent fibers up to 28%. The flammability and chemical resistance of the new developed fibers were characterized. In contrary to what was expected, the encasing of PET with PPS reduced the flame retardancy, though PPS has a higher flame resistance than PET. The chemical resistance of the PET core against hydrolysis was imparted by coextruding a PPS sheath. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
High‐temperature DSC study of polyacrylonitrile precursors during their conversion to carbon fibers
Authors: Wang Yan‐Xiang , Wang Cheng‐Guo , Wu Ji‐Wei , Jing Min
Published: July 2007

The evolution of structure, the changes of properties during the preoxidation, precarbonization, and carbonization of different polyacrylonitrile (PAN) precursors were firstly studied in detail by means of using high‐temperature differential scanning calorimetry (DSC) to characterize with continuous heating from 25 to 1400°C. It was essential to study the thermal behavior of PAN precursors so that proper temperature was determined. Three precursors with different composition, P1: acrylonitrile/itaconic acid (AN/IA) = 98/2 (wt/wt); P2: acrylonitrile/acrylamide (AN/AM) = 98/2 (wt/wt); P3: acrylonitrile/ammonium salt of itaconic acid (AN/AIA) = 98/2 (wt/wt) were, respectively, selected in this study. Comparative results of the DSC curves showed that the heating history influenced greatly the heat quantities released and exothermic position at low temperature of DSC curve, but influenced slightly at higher temperature. Aromatic index, carbon yield (Wc) and weight loss (η) can be calculated. After adjusting the temperature in preoxidation and precarbonization and carbonization technology depending on high‐temperature DSC, the high performance carbon fibers were obtained that tensile strength is 3.56–4.16 GPa, modulus is 235–243 GPa. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Polypropylene fibers containing dispersed clays having improved fire performance. I. Effect of nanoclays on processing parameters and fiber properties
Authors: Horrocks A. Richard , Kandola Baljinder K. , Smart Gillian , Zhang Sheng , Hull T. Richard
Published: July 2007

While the present interest in the use of functionalized nanoclays as additives for improving tensile properties and fire performance in polypropylene thermoplastics has led to a considerable literature, little attention has been given to this polymer in fiber form. In this article, we report the conditions necessary for and the characteristics of filaments and tapes comprising dispersions of functionalized clay in polypropylene–clay prepared by melt compounding polypropylene in a twin screw extruder. A small fraction (1–3% w/w) of modified grafted polypropylene has also been included to improve dispersion of the clay. X‐ray diffraction of hot‐pressed films, coupled with transmission electron microscopic investigation has been used to assess the degree of dispersion of the clay. Clay dispersion at the nanolevel was observed by TEM, but intercalation was not evident from X‐ray study. Compounded samples were melt‐extruded into filaments using a single screw extruder and drawn prior to wind up. The physical properties of the clay‐containing polypropylene filaments showed that presence of dispersed clay increased filament modulus and was supportive of having achieved some degree of nanodispersion. Selected filament samples had sufficiently acceptable textile properties to enable their knitting into fabric samples. The burning behavior of fabric and film samples were observed by limiting oxygen index and cone calorimetry at 35 kW/m2 external heat flux. While the clay presence did not confer flame retardancy, it did change the burning character and encouraged some char formation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Competitive removal of nickel (II), cobalt (II), and zinc (II) ions from aqueous solutions by starch‐graft‐acrylic acid copolymers
Authors: Güçlü Gamze , Güçlü Kubilay , Keleş Sibel
Published: July 2007

Graft copolymerization of acrylic acid (AA) onto starch was carried out with ceric ammonium nitrate as initiator under nitrogen atmosphere. The grafting percentages (GP%) of starch‐graft‐acrylic acid (St‐g‐AA) copolymers were determined. The effect of GP% of St‐g‐AA copolymers on the competitive removal of Co2+, Ni2+, Zn2+ ions from aqueous solution was investigated at different pH (2, 4, 6). The concentrations of each ion in aqueous solution 5 mmol/L. Effects of various parameters such as treatment time, initial pH of the solution and grafting percentage of starch graft copolymers were investigated. Metal ion removal capacities of St‐g‐AA copolymers increased with GP% of the copolymers and pH. The results show that the removal of metal ions followed as given in the order Co2+ > Ni2+ > Zn2+. In this study, metal ion removal capacities were determined by atomic absorption spectrophotometer (AAS). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Structure formation and characterization of PVDF hollow fiber membranes by melt‐spinning and stretching method
Authors: Du Chun‐Hui , Xu You‐Yi , Zhu Bao‐Ku
Published: July 2007

Melt‐spinning and stretching (MS‐S) method was proposed for preparing poly(vinylidene fluoride) (PVDF) hollow fiber membranes with excellent mechanical properties. The morphology and properties of PVDF fibers and membranes were investigated by small angle X‐ray scattering (SAXS), differential scanning calorimeter (DSC), field emission scanning electron microscope, mercury porosimeter, and tensile experiment. SAXS results indicated that the stacked lamellar structure aligned normal to the fiber axis was separated and deformed when the fibers were strained, and the long period of the strained fibers increased accordingly. Factors affecting the membrane properties were mainly spin‐draw ratio, annealing temperature, time, and stretching rate. Experimental results showed that the average pore size, porosity, and N2 permeation of the membranes all increased with the increasing spin‐draw ratios and annealing temperatures. Annealing the nascent PVDF hollow fibers at 145°C for 12 h was suitable for attaining membranes with good performance. In addition, the amount and size of the micropores of the membrane increased obviously with stretching rate. Tensile experiment indicated PVDF hollow fiber membranes made by MS‐S process had excellent mechanical properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Abiotic impacts on spatial and temporal distribution of Corbicula fluminea (Müller, 1774) in the River Minho estuary, Portugal
Authors: Sousa Ronaldo , Rufino Marta , Gaspar Miguel , Antunes Carlos , Guilhermino Lúcia
Published: July 2007

The non‐indigenous species Corbicula fluminea (Müller, 1774) is one of the most invasive bivalves in freshwater ecosystems. This Asian clam was first reported in the River Minho estuary in 1989. After a short period of time, it became the major component of the local benthic fauna in terms of abundance and biomass.

In the autumn of 2004 and 2005, spatial and temporal variations in abundance, biomass and population structure of C. fluminea were investigated at 16 sites in the freshwater subtidal area of the River Minho estuary. Mean abundance and biomass per site ranged from 80 to 4185ind.m−2 and 8.5 to 465.9g AFDWm−2, respectively.

The environmental characterization of the area was performed through multivariate analysis, which revealed three distinct areas subjected to different abiotic conditions. C. fluminea population structure is well correlated with these three distinct areas.

The combination of several abiotic variables determining C. fluminea biomass distribution was evaluated through a stepwise multiple regression. This model showed that redox potential, nutrient concentrations, hardness, organic matter and sediment characteristics explained almost 60% of the variation in C. fluminea biomass in the freshwater subtidal area of the River Minho estuary (R2=59.3%, F[9,86]=13.9, p<0.001).

Improved ecological knowledge is essential for future C. fluminea management, in order to protect local habitats and biodiversity, and to reduce the economic impact of this non‐indigenous invasive species.

Copyright © 2007 John Wiley & Sons, Ltd.
An amalgamation of solid phase peptide synthesis and ribosomal peptide synthesis
Authors: Ottesen Jennifer J. , Bar‐Dagan Maya , Giovani Baldissera , Muir Tom W.
Published: July 2007

Expressed protein ligation (EPL) is a protein semisynthesis technique that allows the site‐specific introduction of unnatural amino acids and biophysical probes into proteins. In the present study, we illustrate the utility of the approach through the generation of two semisynthetic proteins bearing spectroscopic probes. Dihydrofolate reductase containing a single 13C probe in an active site loop was generated through the ligation of a synthetic peptide‐α‐thioester to a recombinantly generated fragment containing an N‐terminal Cys. Similarly, c‐Crk‐II was assembled by the sequential ligation of three recombinant polypeptide building blocks, allowing the incorporation of 15N isotopes in the central domain of the protein. These examples showcase the scope of the protein ligation strategy for selective introduction of isotopic labels into proteins, and the protocols described will be of value to those interested in using EPL on other systems. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90:406–414, 2008.

This article was originally published online as an acceptedpreprint. The “Published Online” date corresponds to the preprintversion. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Renaturation with simultaneous purification of rhG‐CSF from Escherichia coli by ion exchange chromatography
Authors: Wang Chaozhan , Wang Lili , Geng Xindu
Published: July 2007

Protein refolding is a key step for the production of recombinant proteins, especially at large scales, and usually their yields are very low. Application of liquid chromatography to protein refolding is an exciting step forward for this field. In this work, recombinant human granulocyte colony‐stimulating factor (rhG‐CSF) expressed in Escherichia coli was renatured with simultaneous purification by ion exchange chromatography (IEC) with a Q Sepharose FF column. Several chromatographic parameters affecting the refolding yield of the denatured/reduced rhG‐CSF, such as the urea concentration, pH value, concentration and ratio of reduced/oxidized glutathione in the mobile phase, as well as the flow rate of the mobile phase, were investigated in detail and indicated that the urea concentration and the pH value were of great importance. At the optimal conditions, the renatured and purified rhG‐CSF was found to have a specific bioactivity of 3.0 × 108 IU/mg, a purity of 96%, and a mass recovery of 49%. Compared with the usual dilution method, the IEC method developed here is more effective for rhG‐CSF refolding in terms of specific bioactivity and mass recovery. Copyright © 2007 John Wiley & Sons, Ltd.
Intramolecular Electron Transfer in the Dihaem Cytochrome c Peroxidase of Pseudomonas aeruginosa
Authors: Lee Yong , Boycheva Svetlana , Brittain Thomas , Boyd Peter D. W.
Published: July 2007

Mutant forms of the enzyme cytochrome c peroxidase from Pseudomonas aeruginosa, in which the peroxidatic haem ligand (H71) and putative haem‐bridging amino acid (W94) have been mutated, were produced in an E. coli expression system as a means of investigating possible mechanisms of intramolecular electron transfer within the enzyme. EPR spectroscopy indicated the presence of a high‐spin, presumably five‐coordinate, peroxidatic haem site in the H71G and H71G/W94A mutants, whilst the W94A mutant apparently retained the normal six‐coordinate haem structures. In turnover experiments, these mutants show 55, 4, and <1 % activity, respectively, as compared to the wild‐type enzyme. The W94A mutant shows essentially no activity in turnover experiments. Circular dichroism spectroscopy indicates no measurable difference in the secondary structure of the H71G mutant from that of the native enzyme, whilst some small differences are observed for the double mutant. Treatment of the oxidised mutant proteins with hydrogen peroxide, in the absence of preactivation or exogenous reductants, yields products that suggest the formation of a tryptophan radical species in the case of the H71 mutant and the production of a porphyrin radical in the case of the double mutant. These results are discussed in terms of the intramolecular electron transfer in this enzyme.
Counterion‐Dependent Proton‐Driven Self‐Assembly of Linear Supramolecular Oligomers Based on Amino‐Calix[5]arene Building Blocks
Authors: Pappalardo Sebastiano , Villari Valentina , Slovak Sarit , Cohen Yoram , Gattuso Giuseppe , Notti Anna , Pappalardo Andrea , Pisagatti Ilenia , Parisi Melchiorre F.
Published: July 2007

Self‐assembly of a calix[5]arene bearing a 12‐aminododecyl pendant group on the lower rim into supramolecular oligomers through intermolecular iterative inclusion events is readily triggered by contact with acid solutions and is reversed to the amino monomer precursor by treatment with a base.1H NMR data are consistent with the formation of head‐to‐tail assemblies derived fromendo‐cavity inclusion of the alkylammonium moiety. Diffusion NMR and light‐scattering studies provide evidence for the presence of oligomers in solution and show that different counterions and concentrations result in different oligomer sizes, whereas ESI‐MS and SEM investigations, respectively, indicate that self‐assembly also takes place in the gas phase and in the solid state. The growth of these supramolecular oligomers is concentration‐dependent; however, as a consequence of the saline nature of the monomer, it also shows a distinct counterion‐dependence owing to ion‐pairing/solvation effects.
Constitutional Self‐Organization of Adenine–Uracil‐Derived Hybrid Materials
Authors: Arnal‐Hérault Carole , Barboiu Mihai , Pasc Andreea , Michau Mathieu , Perriat Pascal , van der Lee Arie
Published: July 2007

The alkoxysilane nucleobase adenine (A) and uracil (U) precursors described in this paper generate in solution a complex library of hydrogen‐bonded aggregates, which can be expressed in the solid state as discrete higher oligomers. The different interconverting outputs that nucleobases may form by oligomerization define a dynamic polyfunctional diversity that may be “extracted selectively” in solid state by sol–gel transcription, under the intrinsic stability of the system. After the sol–gel process, unique constitutional preference for specific geometries in hybrid materials is consistent with a preferential arrangement of nucleobase systems, favoring the self‐assembly by the Hoogsteen geometry. FTIR and NMR spectroscopy and X‐ray powder diffraction experiments demonstrate the formation of self‐organized hybrid supramolecular materials. Electron microscopy reveals the micrometric platelike morphology of the hybrid materials. The MA–U hybrid material is nanostructured in ordered circular domains of 5 nm in diameter of alternative light and dark rows with an one‐dimensional periodicity of 3.5 Å.
Prevalence of Renal Insufficiency in cancer patients and implications for anticancer drug management
Authors: Launay‐Vacher Vincent , Oudard Stéphane , Janus Nicolas , Gligorov Joseph , Pourrat Xavier , Rixe Olivier , Morere Jean‐François , Beuzeboc Philippe , Deray Gilbert ,   On behalf of the Renal Insufficiency and Cancer Medications (IRMA) Study Group
Published: July 2007

BACKGROUND.

The Renal Insufficiency and Cancer Medications (IRMA) study is a French national observational study. The results from this study of nearly 5000 patients demonstrated the high prevalence of renal impairment in a population of patients with solid tumors.

METHODS.

Every cancer patient who presented at oncology departments that participated in the study over at least 1 of 2 predefined periods during 2004 were included. Renal function was calculated using Cockcroft‐Gault and abbreviated Modification of Diet in Renal Disease (aMDRD) formulae to estimate the prevalence of renal insufficiency (RI) according to the Kidney Disease Outcomes Quality Initiative‐Kidney Disease Improving Global Outcomes definition and stratification. Anticancer drugs were studied with regard to their potential renal toxicity and dosage adjustment.

RESULTS.

Of the 4684 patients from the 15 centers, 7.2% had serum creatinine levels >110 μmol/L. However, when they were assessed using Cockcroft‐Gault and aMDRD formulae, 57.4% and 52.9% of patients had abnormal renal function or RI, respectively. Of the 7181 anticancer drug prescriptions, 53.4% required dose adjustments for RI. Of the patients treated, 79.9% received at least 1 such drug. And 80.1% received potentially nephrotoxic drugs.

CONCLUSIONS.

RI was common in patients with cancer, and drug dosage adjustments often were necessary. Renal function should be evaluated in all cancer patients using either the Cockcroft‐Gault formula or the aMDRD formula, including patients with normal serum creatinine levels. In patients who are at high risk for drug toxicity, the dosage should be adapted to renal function, and the use of nephrotoxic therapies should be avoided whenever possible. Cancer 2007. © 2007 American Cancer Society.
Viewership of pro‐eating disorder websites: Association with body image and eating disturbances
Authors: Harper Kelley , Sperry Steffanie , Thompson J. Kevin
Published: July 2007

Objective:

To evaluate the association between pro‐eating disorder website viewership and concurrent levels of body dissatisfaction and eating disturbance.

Method:

A sample of 1575 women were surveyed for viewership of a variety of websites, including those promoting disordered eating (pro‐eating disorder) and those providing information about eating disorders (professional).

Results:

Individuals who frequented pro‐eating disorder sites had higher levels of body dissatisfaction and eating disturbance than a control group. The group who frequented only professional information websites, but not pro‐eating disorder websites, differed from controls on only one of the four measures of disturbance. The pro‐eating disorder group did not differ from the professional group on any measure.

Conclusion:

The findings offer moderate evidence indicating that viewers of pro‐eating disorder sites have higher levels of disturbance than a control sample of nonviewers, but limited evidence that those who view pro‐eating disorder sites differ from individuals who view professional sites offering information regarding eating disorders. The findings are discussed in light of the difficulty determining causality in this area of inquiry and a cautionary note regarding the potential iatrogenic effects of this type of research is offered. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2008
Gender and age differences in associations between peer dieting and drive for thinness
Authors: Gravener Julie A. , Haedt Alissa A. , Heatherton Todd F. , Keel Pamela K.
Published: July 2007

Objective:

To examine associations between peer dieting and drive for thinness (DT) in men and women of three age groups and to compare rates of perceived vs. reported peer dieting.

Method:

Data came from an epidemiological study in which surveys were completed by women (n = 1,468) and men (n = 592) from three age groups: late adolescent (mean ± SD age: 20.0 ± 1.6 years), adult (30.0 ± 1.6), and midlife (40.1 ± 2.0).

Results:

Significant associations were found between perceived peer dieting and DT in women and men. For women, associations were strongest in late adolescents for same‐sex peers. Associations in men did not differ by age group or peer sex. Expected gender differences in the strength of associations were not found. Reported dieting occurred at or below rates perceived for peers.

Conclusion:

Results may partially account for why DT has been found to decline with age in women, but not men. Longitudinal research is needed to support cross‐sectional findings. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2008
CXCL12‐induced partitioning of flotillin‐1 with lipid rafts plays a role in CXCR4 function
Authors: Giri Banabihari , Dixit Vishwa D. , Ghosh Manik C. , Collins Gary D. , Khan Islam U. , Madara Karen , Weeraratna Ashani T. , Taub Dennis D.
Published: July 2007

Lipid rafts play an important role in signal integration and in the cellular activation of a number of cytokine and growth factor receptors. It has recently been demonstrated that flotillin proteins are recruited to lipid raft microdomains upon cellular activation and play a role in neural cell regeneration, receptor signaling and lymphocyte activation. However, little is known about the relevance of the flotillin proteins during T cell responses to chemoattractant stimulation. To this end, cytoplasmic and lipid raft fractions from human T cells were analyzed for flotillin protein redistribution prior to and after CXCL12 stimulation. Flotillin‐1, but not flotillin‐2, redistributes to lipid rafts upon CXCR4 ligation. Moreover, in CXCL12‐treated T cells, flotillin‐1 also associates with several raft proteins including LAT, CD48 and CD11a but not Lck. In addition, an increase in CXCR4 association with flotillin‐1 in lipid rafts was observed after chemokine treatment. RNAi technology was also utilized to inhibit the expression of flotillin‐1, resulting in an inhibition of CXCL12‐mediated signaling, function and CXCR4 recruitment into lipid rafts. Together, these data suggest that the increased association of cellular flotillin‐1 with lipid raft microdomains during chemokine exposure may play an important role in chemokine receptor signaling and receptor partitioning with lipid rafts.
Quinacrine inhibits the epidermal dendritic cell migration initiating T cell‐mediated skin inflammation
Authors: Gorbachev Anton V. , Gasparian Alexander V. , Gurova Katerina V. , Gudkov Andrei V. , Fairchild Robert L.
Published: July 2007

Quinacrine (QC) is an anti‐inflammatory drug that has been used for the treatment of malaria and rheumatoid diseases. The mechanism(s) underlying the anti‐inflammatory activity of QC remains poorly understood. We recently reported the QC‐mediated inhibition of the NF‐κB pathway using an in vitro model. To test this potential mechanism in vivo, we used the contact hypersensitivity response (CHS) to chemical allergen sensitization and challenge in mice as a model of skin inflammation. The results indicated that QC treatment inhibited NF‐κB activation in the skin during allergen sensitization. This inhibition was reflected by decreased mRNA expression and protein production of the NF‐κB‐dependent cytokines TNF‐α and IL‐1β and the chemokine CCL21 in the skin. The decreases in these cytokines resulted in reduced migration of allergen‐presenting dendritic cells from the skin into skin‐draining lymph nodes and markedly decreased activation of effector CD8+ T cells for the CHS response to allergen challenge (inhibitory concentration 50% or IC50 was 55 mg/kg). These findings reveal a previously unrecognized mechanism of QC‐mediated inhibition of inflammation.
Leptin‐mediated cytokine release and migration of eosinophils: Implications for immunopathophysiology of allergic inflammation
Authors: Wong Chun Kwok , Cheung Phyllis F.‐Y. , Lam Christopher W. K.
Published: July 2007

Leptin is a pleiotropic adipocyte‐derived cytokine used in hypothalamic regulation of body weight and modulation of immune response by stimulating T cells, macrophages and neutrophils. Leptin has been shown to be an eosinophil survival factor. We examined the immunopathological mechanisms for the activation of human eosinophils from healthy volunteers by leptin in allergic inflammation. Adhesion molecules, cytokines and cell migration were assessed by flow cytometry, ELISA and Boyden chamber assay, respectively. Intracellular signaling molecules were investigated by membrane array and Western blot. Leptin could up‐regulate cell surface expression of adhesion molecule ICAM‐1 and CD18 but suppress ICAM‐3 and L‐selectin on eosinophils. Leptin could also stimulate the chemokinesis of eosinophils, and induce the release of inflammatory cytokines IL‐1β and IL‐6, and chemokines IL‐8, growth‐related oncogene‐α and MCP‐1. We found that leptin‐mediated induction of adhesion molecules, release of cytokines and chemokines, and chemokinesis were differentially regulated by the activation of ERK, p38 MAPK and NF‐κB. In view of the above results and elevated production of leptin in patients with allergic diseases such as atopic asthma and atopic dermatitis, leptin could play crucial immunopathophysiological roles in allergic inflammation by activation of eosinophils via differential intracellular signaling cascades.
Introduction of Modified Electronic Parameters – Searching for a Unified Ligand Properties Scale through the Electrophilicity Index Concept
Authors: Makedonas Christodoulos , Mitsopoulou Christiana A.
Published: July 2007

In order to quantify the contribution of mainly, but not only, diimine ligands to the electronic properties of the corresponding complexes, two novel indices, namely modified electronic parameters (ModEP) and electrophilicity, ω, are introduced and discussed in this report. First, we introduce the concept of ModEP, a novel scale relating to the electronic properties of diimine ligands. Mainly on the basis of well‐characterized M(diimine)(dithiolato) complexes (M = Pt, Pd, or Ni), we derive the contribution of the diimine ligand to the reduction potentials of the complexes, and incorporating its contribution to the main charge‐transfer band of the UV/Vis spectra, we obtain our ModEP values. The applicability of the introduced scale to several other classes of diimine compounds (W, Re, and Ru) is then tested. The performance of our scale in predicting the values of the reduction potentials and the position of the charge‐transfer bands is very satisfactory. With this approach, some interesting aspects of ligand coordination were revealed. Next, we employ the recently introduced electrophilicity index ω, in order to correlate our ModEP scale with various other empirical scales that are already known and extensively used. This permits us to unify most known scales, which were primarily derived for different types of ligands (e.g. ModEP for diimines, Tolman's for phosphanes). The proposed method of ω calculation (at the semiempirical AM1 level) avoids any experimental limitation and can be employed even for ligands that are not yet experimentally available, whereas its correlation to the known scales would immediately provide the properties of the compound. This supports the idea that the electrophilicity index could become a powerful tool in coordination and organometallic chemistry.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis, Separation and UV/Vis Spectroscopy of Pyrazino‐quinoxalino‐porphyrazine Macrocycles
Authors: Musil Zbynek , Zimcik Petr , Miletin Miroslav , Kopecky Kamil , Lenco Juraj
Published: July 2007

Unsymmetrical metal‐free and zinc complexes of pyrazino‐quinoxalino‐porphyrazines (PQP) bearing eight diethylamino groups have been synthesized by statistical tetramerization of 2,3‐bis(diethylamino)quinoxaline‐6,7‐dicarbonitrile and 5,6‐bis(diethylamino)pyrazine‐2,3‐dicarbonitrile in lithium butanolate. For this purpose, a new heteroatom‐substituted quinoxaline precursor, 2,3‐dichloro‐6,7‐dicarbonitrile, was prepared and characterized. It is a flexible starting material for new building blocks of quinoxaline‐6,7‐dicarbonitrile derivatives. All the PQPs (including adjacent and opposite isomers) from the statistical mixture were detected and separated by column chromatography on silica and characterized by MALDI‐TOF mass spectrometry, IR, UV/Vis and NMR spectroscopy. The effect of the insertion of benzene rings into the tetrapyrazinoporphyrazine (TPP) system is discussed. Each benzene ring insertion into the TPP system causes a bathochromic shift of 22 nm; the dependence is linear. The final tetra[6,7]quinoxalinoporphyrazines were red‐shifted to 744 and 763 nm for the zinc and metal‐free derivative, respectively. Splitting of the Q‐band was observed for PQPs with lower symmetry.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
One‐Pot Synthesis of Core‐Modified Rubyrin, Octaphyrin, and Dodecaphyrin: Characterization and Nonlinear Optical Properties
Authors: Kumar Rajeev , Misra Rajneesh , Chandrashekar Tavarekere K. , Nag Amit , Goswami Debabrata , Suresh Eringathodi , Suresh Cherumuttathu H.
Published: July 2007

Modified 26π rubyrin, 36π octaphyrin, and 54π dodecaphyrin systems have been synthesized in moderately good yields through acid‐catalyzed condensations of terthiophene diols and tripyrranes. The product distributions are decided both by the acid catalyst concentration and by the nature of the meso substituents. For example, a new isomer of [26]hexaphyrin(1.1.1.1.0.0) (rubyrin) was obtained with 0.3 equiv. of p‐toluenesulfonic acid, when the meso substituent was mesityl in at least one of the precursors. A change of the mesityl substituent for a p‐methoxy substituent in terthiophene diol resulted in the formation of a [3 + 3 + 3 + 3] condensation product – [54]dodecaphyrin(1.1.1.1.0.0.1.1.1.1.0.0) – in addition to the expected rubyrin. Furthermore, an increase in the acid concentration to 0.6 equiv. resulted in the formation of a new [36]octaphyrin(1.1.1.1.1.1.0.0), in addition to the rubyrin and dodecaphyrin. A single‐crystal X‐ray analysis of octaphyrin represents the first example of a planar conformation of an octaphyrin with six meso links. In rubyrin 19, one thiophene ring, opposite to the terthiophene subunit, is inverted, while in octaphyrin 30 one pyrrole ring and two thiophene rings are inverted. The various conformational possibilities tested for the unsubstituted dodecaphyrin 28, at semiempirical level, suggest that the most stable conformation is a figure‐eight. The final geometry optimization of figure‐eight dodecaphyrin was done at the B3LYP/6‐31G* level of DFT. Octaphyrins and dodecaphyrins bind trifluoroacetate anion effectively in their diprotonated forms, the binding constants (K) being 638 M–1 for dodecaphyrin 28, and 415 M–1 for octaphyrin 30. Electrochemical data reveal HOMO destabilization with increasing π electron conjugation, consistently with the large red shifts of the absorption bands. Preliminary studies on the use of these expanded porphyrins as third‐order NLO materials were followed by measurements of their two‐photon absorption (TPA) cross‐sections [σ(2)]. The σ(2) values increase upon going from the 26π rubyrins to the 54π dodecaphyrins, confirming our earlier observation that increases in π‐conjugated electrons increase the TPA values.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
An alternating Crank–Nicolson method for the numerical solution of the phase‐field equations using adaptive moving meshes
Authors: Tan Zhijun , Huang Yanghong
Published: July 2007

An alternating Crank–Nicolson method is proposed for the numerical solution of the phase‐field equations on a dynamically adaptive grid, which automatically leads to two decoupled algebraic subsystems, one is linear and the other is semilinear. The moving mesh strategy is based on the approach proposed by Li et al. (J. Comput. Phys. 2001; 170:562–588) to separate the mesh‐moving and partial differential equation evolution. The phase‐field equations are discretized by a finite volume method in space, and the mesh‐moving part is realized by solving the conventional Euler–Lagrange equations with the standard gradient‐based monitors. The algorithm is computationally efficient and has been successfully used in numerical simulations. Copyright © 2007 John Wiley & Sons, Ltd.
Decomposition methods for time‐domain Maxwell's equations
Authors: Huang Zhi‐Xiang , Sha Wei , Wu Xian‐Liang , Chen Ming‐Sheng
Published: July 2007

Decomposition methods based on split operators are proposed for numerical integration of the time‐domain Maxwell's equations for the first time. The methods are obtained by splitting the Hamiltonian function of Maxwell's equations into two analytically computable exponential sub‐propagators in the time direction based on different order decomposition methods, and then the equations are evaluated in the spatial direction by the staggered fourth‐order finite‐difference approximations. The stability and numerical dispersion analysis for different order decomposition methods are also presented. The theoretical predictions are confirmed by our numerical results. Copyright © 2007 John Wiley & Sons, Ltd.
Equity swaps in a LIBOR market model
Authors: Wu Ting‐Pin , Chen Son Nan
Published: July 2007

This study extends the BGM (A. Brace, D. Gatarek, & M. Musiela, 1997) interest rate model (the London Interbank Offered Rate [LIBOR] market model) by incorporating the stock price dynamics under the martingale measure. As compared with traditional interest rate models, the extended BGM model is both appropriate for pricing equity swaps and easy to calibrate. The general framework for pricing equity swaps is proposed and applied to the pricing of floating‐for‐equity swaps with either constant or variable notional principals. The calibration procedure and the practical implementation are also discussed. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27:893–920, 2007
Posterior cingulate activation during moral dilemma in adolescents
Authors: Pujol Jesus , Reixach Jordi , Harrison Ben J. , Timoneda‐Gallart Carme , Vilanova Joan C. , Pérez‐Alvarez Federico
Published: July 2007

Neuroimaging research examining correlates of adolescent behavioral maturation has focused largely on issues related to higher cognitive development. Currently few studies have explored neural correlates of emotional reactivity in adolescent groups. In this study, we sought to examine the nature of posterior cingulate activation during situations of moral dilemma in normal adolescents. We focused on this region because of emerging evidence that suggests its role in emotionally self‐relevant mental processing. Ten healthy teenagers, aged from 14 to 16 years, underwent three fMRI sequences designed to examine (i) brain responses during moral dilemma; (ii) brain responses during passive viewing of the moral dilemma outcome; and (iii); “deactivation” during a simple cognitive task compared with resting‐state activity. Our main finding was that during moral dilemma, all subjects showed significant activation of the posterior cingulate cortex, and more variable activation of the medial frontal cortex and angular gyrus. Interestingly, these findings were replicated in each subject using the passive viewing task, suggesting that the previous pattern was not specific to moral reasoning or decision making. Finally, six of the ten subjects showed deactivation of the same posterior cingulate region during the cognitive task, indicating some commonality of function between posterior cingulate activity during moral dilemmas and rest. We propose that these posterior cingulate changes may relate to basic neuronal activities associated with processing self‐relevant emotional stimuli. Given the high single‐subject reproducibility of posterior cingulate activations, our findings may contribute to further characterize adolescent emotional reactivity in developmental neuroimaging studies. Hum Brain Mapp, 2008. © 2007 Wiley‐Liss, Inc.
Neural processing of threat cues in social environments
Authors: Han Shihui , Gao Xiaochao , Humphreys Glyn W. , Ge Jianqiao
Published: July 2007

Previous research showed that the processing of overt threat cues formed by evolutionary experience such as snake or angry face induced automatic increased responses of the emotion‐related system consisting of the amygdala, the anterior cingulate, and the orbitofrontal cortex. The present study used functional magnetic resonance imaging (fMRI) to investigate brain circuits involved in perception of threat cues that lack obvious emotion contents but are potentially dangerous in a particular social situation. Subjects were scanned while watching images showing a person in either a safe or a potentially dangerous situation and being asked to detect threat signals or to evaluate the degree of threat. We found that, in contrast with gender identification, threat detection and evaluation were underpinned by a neural network, shared by both male and female subjects, consisting of the medial and lateral frontal cortex, superior parietal lobes, posterior middle temporal cortex, and cerebellum. In addition, detection of threat cues was associated with stronger posterior parietal activation for males than females. Our findings suggest that neural processing of evolutionary unprepared threat cues in social environments does not necessarily involve the emotion‐related neural system and is influence by evolutionary pressure on sex differences. Hum Brain Mapp, 2008. © 2007 Wiley‐Liss, Inc.
Memory in the aging brain: Doubly dissociating the contribution of the hippocampus and entorhinal cortex
Authors: Yonelinas Andrew P. , Widaman Keith , Mungas Dan , Reed Bruce , Weiner Michael W. , Chui Helena C.
Published: July 2007

Since the time of Aristotle it has been thought that memories can be divided into two basic types; conscious recollections and familiarity‐based judgments. Neuropsychological studies have provided indirect support for this distinction by suggesting that different regions within the human medial temporal lobe (MTL) are involved in these two forms of memory, but none of these studies have demonstrated that these brain regions can be fully dissociated. In a group of nondemented elderly subjects, we found that performance on recall and recognition tests was predicted preferentially by hippocampal and entorhinal volumes, respectively. Structural equation modeling revealed a double dissociation, whereby age‐related reductions in hippocampal volume resulted in decreases in recollection, but not familiarity, whereas entorhinal volume was preferentially related to familiarity. The results demonstrate that the forms of episodic memory supported by the human hippocampus and entorhinal cortex can be fully dissociated, and indicate that recollection and familiarity reflect neuroanatomically distinct memory processes. © 2007 Wiley‐Liss, Inc.
A numerical model for simulating Hortonian overland flow on tropical hillslopes with vegetation elements
Authors: Ajayi Ayodele E. , van de Giesen Nick , Vlek Paul
Published: July 2007

This paper describes a two‐dimensional hydrodynamic model that characterizes surface runoff process resulting from a varying rainfall intensity event, on an infiltrating soil surface. The soil surface has spatially varied soil physical, hydraulic and microtopographic characteristics. Infiltration process is modelled with the Philip two‐term equation and the time before ponding approximated with the time compression algorithm. Vegetation is modelled as a dynamic component with the modified Gash model. The equation is solved with a modified second order Leapfrog explicit finite difference scheme with centred time and space derivatives. The model was validated with standard analytical solutions. Evaluation with results from field campaigns in the Volta Basin of West Africa during the 2002 rainfall season indicates good agreement, with r2 values ranging from 0·89 to 0·96. The developed method will be useful in studying the dynamics of surface runoff generation under complex microtopographic conditions, spatially varying soil hydraulic characteristics and temporally dynamic rainfall intensity, as found in many tropical catchments. Copyright © 2007 John Wiley & Sons, Ltd.
When infants grow up in multiperson relationship systems
Authors: Mchale James P.
Published: July 2007

Despite prompts from the field of family therapy since its inception, contemporary infant mental health theory and practice remain firmly rooted in and guided by dyadic‐based models. Over the past 10 years, a groundswell of new empirical studies of triadic and family group dynamics during infancy have substantiated that which family theory has contended for decades: looking beyond mother‐infant or father‐infant dyads reveals a myriad of critically important socialization influences and dynamics that are missed altogether when relying on informant reports or dyad‐based interactions. Such family‐level dynamics emerge within months after infants are born, show coherence through time, and influence the social and emotional adjustment of children as early as the toddler and preschool years. This report summarizes key findings from the past decade of empirical family studies, highlights several areas in need of further conceptual development and empirical study by those who work with infants and their families, and outlines important implications of this body of work for all practicing infant mental health professionals.