bluuebunny/crossref_metadata_2025 huggingface dataset:
Microcomposite electrochemical capacitor: Electrocoating of poly[N‐(hydroxymethyl)carbazole] onto carbon fiber, surface morphology, spectroscopic surface characterization, electrochemical impedance spectroscopy
Authors: Sarac A. Sezai , Parlak Elif Altürk , Serhatlı Ersin , Çakır Tuba
Published: January 2007

N‐(Hydroxymethyl)carbazole (MeOHCz) was electrocoated on carbon fiber micro electrodes (diameter ∼ 7 μm) in different solvents by cyclovoltammetric method as thin film (0.17–2.73 μm). Surface characterization of electrocoated poly[N‐(hydroxymethyl)carbazole] of carbon fiber microelectrode (CFME) was performed by reflectance FTIR spectroscopy, scanning electron microscopy, and cyclic voltammetry. Capacitor behavior of modified CFME was studied by electrochemical impedance spectrometry. The deposition rate of polymer growth affected the redox parameters of resulting coated CFME. The solvent effect on the redox and capacitor behavior of poly[N‐(hydroxymethyl)carbazole] (PMeOHCz)‐coated CFME was investigated, and electroactivity in acetonitrile (ACN) was the highest among the investigated solvents. On the other hand, the electrocoated polymer exhibited the faster charge/discharge process in propylene carbonate (PC). PMeOHCz thin film was very stable up to 1000 mV/s in ACN, PC, and dichloromethane (CH2Cl2). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 238–246, 2007
Influence of pigment properties on UV‐curing efficiency
Authors: Macarie Lavinia , Ilia Gheorghe
Published: January 2007

The curable formulations containing monomer‐diacrylate, photoinitiator‐p‐methoxybenzoyldiphenylphosphine oxide/benzyldimethylketal, additive reactive‐triethylamine, and inorganic thermoresistant pigments‐white, red, green, and blue were cured by UV exposure films. A series of experiments was carried out to investigate the relationship between the particle size distribution of the inorganic pigment and the colorimetric and mechanical properties of the UV acrylic curable coatings. Pendulum hardness and appearance of the films depend on the content and particle size distribution of the pigment. Optimal particle size distribution and pigment content were established to obtain the best films concerning their pendulum hardness and chromatic parameters. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 247–252, 2007
Facile fabrication of macroporous polyimide films with pores distributing on one side
Authors: Deng Yongqiang , Zhou Hongwei , Dang Guodong , Rao Xianhua , Chen Chunhai
Published: January 2007

Herein, we report on direct preparation of macroporous polyimide (PI) films with pores distributing on one side, the method of which relies on sedimentation of ceramic spheres in polyamic acid (PAA) solutions in a gravitational field and imidization of PAA/ceramic spheres mixtures to obtain PI/ceramic spheres hybrid films followed by curing in dilute hydrofluoric (HF) acid. In this strategy, the curing of the hybrid films in HF acid leads to the formation of pores. The introduction of pores makes the room‐temperature dielectric constants of the macroporous films lower than that of pure PI film. Moreover, the macroporous PI films have improved Young's moduli and higher thermal stability in nitrogen atmosphere. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 261–266, 2007
Linear‐dendritic ABA triblock copolymers as nanocarriers
Authors: Adeli M. , Zarnegar Z. , Dadkhah A. , Hossieni R. , Salimi F. , Kanani A.
Published: January 2007

Linear‐dendritic ABA triblock copolymers containing PEG were used for transport the small guest molecules such as 5,7‐dibromo‐8‐hydoxy quinoline, ibuprofen, and Congo red. Nanocarriers containing guest molecules were soluble in water and in some of the organic solvents. Encapsulated guest molecules were soluble in some of the solvents, which they cannot be solved in them solely, for example, chloroform is a very poor solvent for Congo red, but encapsulated Congo red by nanocarriers is soluble in chloroform. The linear‐dendritic copolymers/guest molecule complexes were stable at room temperature for about 10 months; during this time, guest molecules did not release from linear‐dendritic copolymers/guest molecule complexes. The controlled release of guest molecules from linear‐dendritic copolymers/guest molecule complexes in vitro conditions also was investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 267–272, 2007
Poly(ethylene terephthalate) copolymers that contain 5‐tert‐butylisophthalic acid and 1‐3/1‐4‐cyclohexanedimethanol: Synthesis, characterization, and properties
Authors: Tsai Yuhsin , Fan Cheng‐Hsing , Hung Chi‐Yuan , Tsai Fuu‐Jen
Published: January 2007

The effects of incorporating 5‐tert‐butylisophthalic acid (tBI) and 1‐3/1‐4 cyclohexanedimethanol (CHDM) in the polymer chain of poly(ethylene terephthalate) (PET) on the crystallization behavior and thermal, optical and tensile properties of this polyester (PETGB) were evaluated. These random copolyesters that contained between 0 and 20 mol % of CHDM and between 0 and 10 mol % of tBI units were prepared by esterification followed by melt copolycondensation. The compositions and molecular weights of the copolyesters were determined by 1H‐NMR spectroscopy and viscometry, respectively. The composition of the polyester was consistent with the composition of the feed. The intrinsic viscosities of the copolymers ranged between 0.62 and 0.74 dL/g. The thermal behaviors were investigated over the entire range of copolymer compositions, using DSC under the heating and cooling rate of 20°C/min and TGA. The copolyesters with tBI and CHDM of < 20 mol % were crystallizable, whereas the copolyesters with tBI and CHDM of ≥ 20 mol % were amorphous. They appeared to be stable up to 395°C. The optical transmissions of the amorphous polyesters were more than 88% in the visible region. The mechanical behavior was investigated by performing a tensile test. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 279–285, 2007
Isothermal cold crystallization kinetics of polylactide/nucleating agents
Authors: Liao Ruogu , Yang Bin , Yu Wei , Zhou Chixing
Published: January 2007

The isothermal cold crystallization kinetics of polylactide (PLA)/nucleating agents (CaCO3, TiO2, and BaSO4, content from 0.5–2.0 wt %) was investigated by differential scanning calorimetry in the temperature range of 120–124°C. With blending nucleating agents, the crystallinity of PLA had a maximum crystallinity of 14.9%. Crystallization rate decreased with increasing crystallization temperature in the researched content range. The crystallization rate followed the Avrami equation with the exponent n around 4.5. From Lauritzen–Hoffman equation, the nucleation parameter Kg was estimated. And from the value of Kg, regime II crystallization behavior can be concluded. Then the lateral and fold surface free energy were calculated from Kg. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 310–317, 2007
Statistical principal components analysis for retrieval experiments
Authors: Dinçer Bekir Taner
Published: January 2007

In this article, the statistical principal components analysis (PCA) is proposed as a method for performance comparisons of different retrieval strategies. It is shown that the PCA method can reveal implicit performance relations among retrieval systems across information needs (i.e., queries, topics). For illustration, the TREC 12 robust track data have been reevaluated by the PCA method and have been shown to reveal easily the performance relations that are hard to see with traditional techniques. Therefore, PCA promises a uniform evaluation framework that can be used for large‐scale evaluation of retrieval experiments. In addition to the mean average precision (MAP) measure, relative analytic distance (RAD) is proposed as a new performance summary measure based on the same notion introduced by PCA.
A Highly Fluorescent Anthracene‐Containing Hybrid Material Exhibiting Tunable Blue–Green Emission Based on the Formation of an Unusual “T‐Shaped” Excimer
Authors: Zhang Guoqi , Yang Guoqiang , Wang Shuangqing , Chen Qingqi , Ma Jin Shi
Published: January 2007

A series of flexible bis(9‐anthryldiamine) ligands (L1–L3) linked with alkyl spacers of different chain length was synthesized and characterized, in order to investigate the coordination behavior of these diamine ligands with metal ions (Zn2+, etc.) based on fluorescence measurements. The results showed that, in the case of anthryldiamine ligands bearing two‐ or four‐carbon links, the zinc ion induced a chelation‐enhanced fluorescence (CHEF) effect in aqueous media, while a trace amount of water could selectively quench the blue emission of the ZnII complex with a three‐carbon‐linked ligand (1). Meanwhile, the introduction of more water (concentration >11 %) resulted in the formation of a new green luminescent species; the luminescence intensity was enhanced stepwise to a maximum with addition of approximately 30 % water in THF solution. The peak position (centered at approximately 500 nm) and the lifetime measurement (τ=19.59 ns) indicated that the green luminescence was attributable to a novel edge‐to‐face dimeric conformation (“T‐shaped” conformation) of anthracene, and not to the more common face‐to‐face dimeric conformation. Accordingly, 1H NMR spectroscopic studies in nonaqueous or aqueous solution confirmed this T‐shaped conformation, which is consistent with the results of single‐crystal X‐ray structure analysis and solid‐state photoluminescence studies.
Voltage mode and current mode Tow Thomas bi‐quadratic filters using inverting CCII
Authors: Soliman Ahmed M.
Published: January 2007

A voltage mode Tow Thomas bi‐quadratic filter using the inverting second‐generation current conveyor (ICCII) is given. The filter has high input impedance, employs two grounded capacitors, and has independent control on Q, independent control on the band‐pass and low‐pass response gain. Three alternative current mode filters are generated from the voltage mode circuit. The three circuits have zero input impedance, employ grounded capacitors and have independent control on Q. Two of the circuits have also all resistors grounded and the other uses only ICCII−and has only one floating resistor. Copyright © 2007 John Wiley & Sons, Ltd.
Identification of a minimal region of loss on the short arm of chromosome 1 in Wilms tumor
Authors: Tamimi Yahya , Ziebart Kay , Desaulniers Nancy , Dietrich Kevin , Grundy Paul
Published: January 2007

We have analyzed the short arm of chromosome 1 using loss of heterozygosity (LOH) analysis in Wilms tumors (WT) to identify a minimal region of loss. 1909 WT, 22 malignant rhabdoid tumors of the kidney and 90 clear cell carcinomas of the kidney (CCSK) were subjected to LOH analysis using five markers flanked by D1S243 and D1S244. 225 WT and 4 CCSK displayed LOH for this region. A group of 16 cases which had lost heterozygosity for at least one locus but also retained heterozygosity for at least one locus within this region were more finely analyzed using a panel of 24 microsatellite markers. A minimum region of loss located between D1S2694 and D1S244 spanning an area of 3.23 Mb was found in 15/16 of these tumors. No evidence for a second locus within this region was identified. This region of loss overlaps that found in neuroblastoma and harbors candidate genes highly expressed in fetal kidney i.e., LZIC, ICAT, and DNB5. Denaturing HPLC and quantitative RT‐PCR analysis of these three genes, however, revealed no aberrations in WT samples retaining heterozygosity (8 cases) or displaying LOH 1p (8 cases). Further studies are required to identify the presumed tumor suppressor gene located within this region of 1p. © 2007 Wiley‐Liss, Inc.
A micro‐RNA signature associated with race, tumor size, and target gene activity in human uterine leiomyomas
Authors: Wang Tongsheng , Zhang Xinmin , Obijuru Laura , Laser Jordan , Aris Virginie , Lee Peng , Mittal Khush , Soteropoulos Patricia , Wei Jian‐Jun
Published: January 2007

Human uterine leiomyomas (ULMs) are the most common neoplasms of women. Many genes are dysregulated in ULMs and some of this dysregulation may be due to abnormal expression of micro‐RNAs (miRNAs). In this study, 55 ULMs and matched myometrium were collected from 41 patients for microarray‐based global miRNA expression analysis. Of 206 miRNAs examined, 45 miRNAs were significantly up‐ or down‐regulated in ULMs in comparison to the matched myometrium (P < 0.001). The top five dysregulated miRNAs in ULMs are the let‐7 family, miR‐21, miR‐23b, miR‐29b, and miR‐197. Four polycistronic clusters of miRNAs were either up‐ or down‐regulated, but not in a mixed pattern, indicative of coordinated regulation of these miRNAs. Significance analysis revealed that subsets of miRNAs were strongly associated with tumor sizes and race. By prediction analysis we identified some important tumorigenic genes previously identified in ULMs that may be targeted by the dysregulated miRNAs. HMGA2 was identified as one of target genes of the let‐7 family of miRNAs and has been found to be suppressed by let‐7 in vitro. (This article contains Supplementary material available at http://www.interscience.wiley.com/jpages/1045‐2257/suppmat.) © 2007 Wiley‐Liss, Inc.
Gains of REL in primary mediastinal B‐cell lymphoma coincide with nuclear accumulation of REL protein
Authors: Weniger Marc A. , Gesk Stefan , Ehrlich Steve , Martin‐Subero José I. , Dyer Martin J. S. , Siebert Reiner , Möller Peter , Barth Thomas F. E.
Published: January 2007

Gains or amplifications of the REL locus are frequently seen in primary mediastinal B‐cell lymphoma (PMBL). In classical Hodgkin's lymphoma, genomic overrepresentation of REL correlated with nuclear REL protein accumulation. To investigate the correlation between REL gene copies and its RNA and protein expression in PMBL, we analyzed genomic, transcriptional, and protein levels in 20 PMBLs and the PMBL derived cell lines MedB‐1 and Karpas1106P. We found gains/amplifications in 75% of the PMBLs by fluorescence in situ hybridization (FISH) and genomic REL overrepresentation in the PMBL lines. Three of the five PMBLs with amplifications displayed elevated REL transcripts, while only 3/10 PMBLs with gains showed increased REL transcripts by real‐time PCR. One PMBL without gains displayed increased REL transcription. REL protein expression exhibited a variable pattern across the PMBLs except for a single case that was completely negative by immunohistochemistry despite having gained REL. Although transcript levels were generally low and nuclear REL staining was weak in the lymphoma cell lines, these nevertheless exhibited high NF‐κB activation. By fluorescence immunophenotyping and interphase cytogenetics as a tool for investigation of neoplasms, genomic gains/amplifications of REL significantly correlated with nuclear REL expression (P < 0.05). In conclusion, the frequent genomic overrepresentation of REL in PMBL does not necessarily trigger an increased transcription/translation of REL. However, combined genomic and protein analysis revealed a significant association of gained REL and nuclear REL accumulation at the single cell level. © 2007 Wiley‐Liss, Inc.
Inhibiting cell cycle progression reduces reactive astrogliosis initiated by scratch injury in vitro and by cerebral ischemia in vivo
Authors: Zhu Zhou , Zhang Qiang , Yu Zhiyuan , Zhang Liang , Tian Daishi , Zhu Suiqiang , Bu Bitao , Xie Minjie , Wang Wei
Published: January 2007

Astrogliosis occurs in a variety of neuropathological disorders and injuries, and excessive astrogliosis can be devastating to the recovery of neuronal function. In this study, we asked whether reactive astrogliosis can be suppressed in the lesion area by cell cycle inhibition and thus have therapeutic benefits. Reactive astrogliosis induced in either cultured astrocytes by hypoxia or scratch injury, or in a middle cerebral artery occlusion (MCAO) ischemia model were combined to address this issue. In the cultured astrocytes, hypoxia induced a cell cycle activation that was associated with upregulation of the proliferating cell nuclear marker (PCNA). Significantly, the cell cycle inhibitor, olomoucine, inhibited hypoxia‐induced cell cycle activation by arresting the cells at G1/S and G2/M in a dose‐dependent manner and also reversed hypoxia‐induced upregulation of PCNA. Also in the cultured astrocytes, scratch injury induced reactive astrogliosis, such as hypertrophy and an increase in BrdU(+) astrocytes, both of which were ameliorated by olomoucine. In the MCAO ischemia mouse model, dense reactive glial fibrillary acidic protein and PCNA immunoreactivity were evident at the boundary zone of focal cerebral ischemia at days 7 and 30 after MCAO. We found that intraperitoneal olomoucine administration significantly inhibited these astrogliosis‐associated changes. To demonstrate further that cell cycle regulation impacts on astrogliosis, cyclin D1 gene knockout mice (cyclin D1−/−) were subjected to ischemia, and we found that the percentage of Ki67‐positive astrocytes in these mice was markedly reduced in the boundary zone. The number of apoptotic neurons and the lesion volume in cyclin D1−/− mice also decreased as compared to cyclin D1+/+ and cyclin D1+/− mice at days 3, 7, and 30 after local cerebral ischemia. Together, these in vitro and in vivo results strongly suggest that astrogliosis can be significantly affected by cell cycle inhibition, which therefore emerges as a promising intervention to attenuate reactive glia‐related damage to neuronal function in brain pathology. © 2007 Wiley‐Liss, Inc.
Modifications of the fibroblast growth factor‐2 gene led to a marked enhancement in secretion and stability of the recombinant fibroblast growth factor‐2 protein
Authors: Chen Shin‐Tai , Gysin Reinhard , Kapur Sonia , Baylink David J. , William Lau K.‐H.
Published: January 2007

Progress in FGF‐2 gene therapy has been hampered by the difficulty in achieving therapeutic levels of FGF‐2 secretion. This study tested whether the addition of BMP2/4 hybrid secretion signal to the FGF‐2 gene and mutation of cys‐70 and cys‐88 to serine and asparagine, respectively, would increase the stability and secretion of active FGF‐2 protein in mammalian cells using MLV‐based vectors. Single or double mutations of cys‐70 and cys‐88 to ser‐70 and asp‐88, respectively, markedly increased the amounts of FGF‐2 protein in conditioned media and cell lysates, which may be due to glycosylation, particularly at the mutated asp‐88 residue. Addition of BMP2/4 secretion signal increased FGF‐2 secretion, but also suppressed FGF‐2 biosynthesis. The combination of BMP2/4 secretion signal and double cys‐70 and cys‐88 mutations increased the total amount of secreted FGF‐2 protein >60‐fold. The modifications did not alter its ability to stimulate cell proliferation and Erk1/2 phosphorylation in marrow stromal cells or its ability to bind heparin in vitro, suggesting that the modified FGF‐2 protein was functionally as effective as the unmodified FGF‐2. An ex vivo application of rat skin fibroblasts (RSF) transduced with the modified FGF‐2 vector in a subcutaneous implant model showed that rats with implants containing cells transduced with the modified FGF‐2 vector increased serum FGF‐2 level >15‐fold, increased growth of the implant, and increased vascularization within the implant, compared to rats that received implants containing β‐galactosidase‐ or wild‐type FGF‐2‐transduced control cells. This modified vector may be useful in FGF‐2 gene therapy investigations. J. Cell. Biochem. 100: 1493–1508, 2007. © 2007 Wiley‐Liss, Inc.
Human Raf‐1 proteins associate with Rad24 and Cdc25 in cell‐cycle checkpoint pathway of fission yeast, Schizosaccharomyces pombe
Authors: Lee Michael , Yoo Hyang‐Sook
Published: January 2007

Raf‐1 is a serine/threonine protein kinase that connects cell surface receptor signals to nuclear transcription factors. By screening Schizosaccharomyces pombe (S. pombe) cDNA library, we isolated Rad24, which is a 14‐3‐3 homolog that is important in the DNA damage checkpoint in S. pombe, as a Raf‐1 interacting protein. The interaction found in yeast was confirmed by co‐immunoprecipitation. Furthermore, Cdc25, which has been known to bind to Rad24, also associated with Raf‐1 and was phosphorylated in vitro by catalytically active Raf‐1. However, in the presence of Raf‐1, an interaction between Rad24 and Cdc25 was inhibited in triple hybrid assay, indicating that Raf‐1 inhibits the interaction between Rad24 and Cdc25. An in vitro competition assay showed that the binding of Cdc25 and of Rad24 to Raf‐1 is mutually exclusive. Western blots of whole cell lysates probed with polyclonal antibodies specific for tyrosine‐15‐phosphorylated Cdc2 showed that overproduction of Rad24 led to the dephosphorylation of tyrosine residue on Cdc2, which is known to be activated through dephosphorylation by Cdc25 phosphatase. Unexpectedly, overexpression of catalytically inactive mutant protein of Raf‐1, S624A, also caused tyrosine dephosphorylation of Cdc2. Thus, these data suggest that Raf‐1 may interfere with the role of Rad24 by competing with Rad24 for binding to Cdc25 or a direct phosphorylation of Cdc25, bypassing the checkpoint pathway in DNA repair through Cdc25 activation. J. Cell. Biochem. 101: 488–497, 2007. © 2007 Wiley‐Liss, Inc.
Identification of mechanosensitive genes in osteoblasts by comparative microarray studies using the rotating wall vessel and the random positioning machine
Authors: Patel Mamta J. , Liu Wenbin , Sykes Michelle C. , Ward Nancy E. , Risin Semyon A. , Risin Diana , Jo Hanjoong
Published: January 2007

Weightlessness or microgravity of spaceflight induces bone loss due in part to decreased bone formation by unknown mechanisms. Due to difficulty in performing experiments in space, several ground‐based simulators such as the Rotating Wall Vessel (RWV) and Random Positioning Machine (RPM) have become critical venues to continue studying space biology. However, these simulators have not been systematically compared to each other or to mechanical stimulating models. Here, we hypothesized that exposure to RWV inhibits differentiation and alters gene expression profiles of 2T3 cells, and a subset of these mechanosensitive genes behaves in a manner consistent to the RPM and opposite to the trends incurred by mechanical stimulation of mouse tibiae. Exposure of 2T3 preosteoblast cells to the RWV for 3 days inhibited alkaline phosphatase activity, a marker of differentiation, and downregulated 61 and upregulated 45 genes by more than twofold compared to static 1 g controls, as shown by microarray analysis. The microarray results were confirmed by real‐time PCR and/or Western blots for seven separate genes and proteins includingosteomodulin,runx2, andosteoglycin. Comparison of the RWV data to the RPM microarray study that we previously published showed 14 mechanosensitive genes that changed in the same direction. Further comparison of the RWV and RPM results to microarray data from mechanically loaded mouse tibiae reported by an independent group revealed that three genes includingosteoglycinwere upregulated by the loading and downregulated by our simulators. These mechanosensitive genes may provide novel insights into understanding the mechanisms regulating bone formation and potential targets for countermeasures against decreased bone formation during space flight and in pathologies associated with lack of bone formation. J. Cell. Biochem. 101: 587–599, 2007. © 2007 Wiley‐Liss, Inc.
Cisplatin cytotoxicity in organ of corti‐derived immortalized cells
Authors: Previati Maurizio , Lanzoni Irene , Astolfi Laura , Fagioli Francesco , Vecchiati Giorgio , Pagnoni Antonella , Martini Alessandro , Capitani Silvano
Published: January 2007

Cisplatin is an anticancer drug currently used in the treatment of genital and head and neck tumors. Its use in these and other types of tumors is narrowed by onset of chemoresistance and severe undesired side effects, like as nephro‐ and ototoxicity, whose mechanisms of action are only partially understood. In the present study we investigated the effects of cisplatin (cis‐dichlorodiaminoplatin, CDDP) on a cell line (OC‐k3) developed from organs of Corti of transgenic mice. We observed at 48 h that cell death due to cisplatin was time and concentration‐dependent. The cell death displayed some morphological hallmarks of apoptosis, including nuclear fragmentation into several large nuclear fragments, surrounded by a rearranged and thickened actin cytoskeleton. No DNA laddering was detected, suggesting absence of endonuclease activity, nor annexin V positivity, suggesting absence of phosphatidylserine externalization. Several molecules protected the cells against CDDP induced cytotoxicity, including methionine, suramin and PD98059. Methionine reduced CDDP‐uptake, while suramin, a polycathionic compound a specifically binding external proteins, did not. This finding suggested that suramin could exert its protective effect by acting on an intracellular transduction pathway. We tested this hypothesis by studying the effect of suramin and PD98059, a MEK inhibitor, on the mitogen activated protein kinase (MAPK) cascade. After CDDP treatment, we found an increase of phosphorylation of extracellular regulated kinases (ERK)1/2, that could be inhibited by PD98059 and suramin. These data suggest that ERK pathways can play a role in mediating the cell death induction in presence of a CDDP challenge. J. Cell. Biochem. 101:1185–1197, 2007. © 2007 Wiley‐Liss, Inc.
Easy preparative scale syntheses of labelled xanthines: caffeine, theophylline and theobromine
Authors: Balssa Frédéric , Bonnaire Yves
Published: January 2007

Several easy preparative scale (0.5–1.5 g) syntheses of deuterium labelled caffeine, theophylline and theobromine are described. Some new selective syntheses of theophylline and theobromine have been developed. Labelled xanthines are of great interest in qualitative or quantitative isotope dilution‐mass spectrometry, coupled with gas or liquid chromatography, currently performed in anti‐doping and forensic laboratories. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of (S)‐cyano(3‐phenoxyphenyl)methyl (1R,3R)‐ 3‐[(1Z)‐2‐chloro‐3,3,3‐trifluoro‐1‐propenyl]‐2,2‐dimethylcyclopropanecarboxylate‐1‐14C
Authors: Johnson Peter L.
Published: January 2007

γ‐Cyhalothrin (1a), (S)‐cyano(3‐phenoxyphenyl)methyl (1R,3R)‐3‐[(1Z)‐2‐chloro‐3,3,3‐trifluoro‐1‐propenyl]‐2,2‐dimethylcyclopropanecarboxylate, is a single‐isomer, synthetic pyrethroid insecticide marketed by Pytech Chemicals GmbH, a joint venture between Dow AgroSciences and Cheminova A/S. As a part of the registration process there was a need to incorporate a carbon‐14 label into the cyclopropyl ring of this molecule. A high yielding radiochemical synthesis of γ‐cyhalothrin was developed from readily available carbon‐14 labeled N‐t‐Boc protected glycine. This seven step synthesis, followed by a preparative normal phase HPLC separation of diastereomers, provided 21.8 mCi of γ‐cyhalothrin‐1‐14C (1b) with >98% radiochemical purity. Copyright © 2007 John Wiley & Sons, Ltd.
Improved method to quantify intracellular zidovudine mono‐ and triphosphate in peripheral blood mononuclear cells by liquid chromatography‐tandem mass spectrometry
Authors: Compain Séverine , Durand‐Gasselin Lucie , Grassi Jacques , Benech Henri
Published: January 2007

The determination of intracellular triphosphate metabolites of nucleoside analogs used in anti‐HIV therapy is very challenging. Despite the well‐known sensitivity and selectivity of LC‐MS/MS, the measurement of the triphosphate metabolite of zidovudine (AZT‐TP) remains difficult because of the interferences induced by endogenous nucleotides triphosphates.

We describe a new approach that allows improved determination of AZT‐TP simultaneously with AZT‐monophosphate (MP). This was obtained, first, by monitoring a transition from the molecular ion of AZT‐TP to a minor but very specific product ion. Then, the spiking of samples with a constant amount of AZT‐TP allowed the signal to emerge from background, leading to increased sensitivity. Finally, the analytical run time was reduced to less than 10 min. The low limits of quantification were at 150 and 300 fmol per sample for AZT‐TP and AZT‐MP, respectively. Recoveries were higher than 85%. Inaccuracy and precision were lower than 10% and 15% (17% at the limit of quantification), respectively.

The new method offers the possibility of determining simultaneously other nucleotide phosphates, as shown here for d4T‐TP (the triphosphate metabolite of another nucleoside analog, stavudine or d4T) and 2′‐deoxythymidine‐5′‐triphosphate or dTTP (the corresponding natural nucleotide triphosphate). Copyright © 2007 John Wiley & Sons, Ltd.
Inter‐individual variability in the expression of the mutated form of hPS1M146L determined the production of Aβ peptides in the PS1xAPP transgenic mice
Authors: Caballero Cristina , Jimenez Sebastian , Moreno‐Gonzalez Ines , Baglietto‐Vargas David , Sanchez‐Varo Raquel , Gavilan M. Paz , Ramos Blanca , del Rio Juan Carlos , Vizuete Marisa , Gutierrez Antonia , Ruano Diego , Vitorica Javier
Published: January 2007

The detection of the early phenotypic modifications of Alzheimer's disease (AD) models is fundamental to understand the progression and identify pharmacologic targets of this pathology. However, a large variability within different models and between age‐matched mice from the same model has been observed. This variability could be due to heterogeneity in the Aβ production. Present results showed the existence of a large variability in the Aβ deposition in both hippocampus and cortex in 6‐month‐old PS1xAPP mice. This variability was not due to the expression of hAPP751SL, however, linear relationship between hPS1M146L mRNA and Aβ production was identified. The Aβ content was related to the incorporation of the hPS1M146L into functional γ‐secretase complexes, detected by the presence of the corresponding human or endogenous PS1‐CTFs. Animals expressing low amount of hPS1M146L mRNA, displayed low hPS1‐CTF incorporation and produced a low amount of Aβ peptides. Conversely, mice with relatively high hPS1 mRNA expression displayed high hPS1‐CTF and high Aβ deposition. Furthermore, the Aβ total and Aβ1‐42 content was increased dramatically by the expression of hPS1M146L (as compared with transgenic APPsl littermates). Therefore, variations in the expression of transgenic form of hPS1M146L in this model, or even between different models, influenced strongly the incorporation of the mutated PS1 into functional γ‐secretase complexes, the production of Aβ peptides and, in consequence, the detrimental effects of Aβ peptides. These data might implicate an “apparent gain‐of‐function” of the γ‐secretase complex by the expression of the mutated PS1M146L. © 2007 Wiley‐Liss, Inc.
Seasonal sea‐level forecasts by canonical correlation analysis—an operational scheme for the U.S.‐affiliated Pacific Islands
Authors: Chowdhury MD. Rashed , Chu Pao‐Shin , Schroeder Thomas , Colasacco Nicole
Published: January 2007

The objective of this study is to develop an operational canonical correlation analysis (CCA) statistical model for sea‐level forecasts in the U. S.‐affiliated Pacific Islands (USAPI) with lead times of several months or longer. The El Niño‐Southern Oscillation (ENSO) climate cycle and the sea‐surface temperatures (SSTs) in the tropical Pacific Ocean are taken as the primary factors in modulating sea‐level variability on the seasonal time scales.

Observations revealed that the sea‐level variations in the USAPI are sensitive to ENSO cycle with low sea level during El Niño and high sea level during La Niña events. The correlation between the sea‐level variability and the fluctuations of tropical Pacific SSTs has been found to be strong. The cross‐validated results indicated that the SST‐based CCA model is potentially useful in predicting seasonal sea‐level variations in the USAPI. For all target seasons at 1‐ and 2‐season lead times, the average correlation skill has been found to be 0.50 or better. Based on this operational CCA model, the real‐time forecasts for seasonal sea‐level variations (i.e. deviations with respect to climatology) are published at the official web site of Pacific ENSO Applications Center (PEAC) (http://lumahai.soest.hawaii.edu/Enso/peu/update.html) for planning and decision options regarding hazard management in the USAPI. Copyright © 2007 Royal Meteorological Society
Integration of biophysical and socio‐economic factors to assess soil erosion hazard in the Upper Kaligarang Watershed, Indonesia
Authors: Halim Rohlini , Clemente Roberto S. , Routray Jayant K. , Shrestha Rajendra P.
Published: January 2007

Soil erosion is one form of land degradation, which is caused by the interacting effects of numerous factors such as biophysical characteristics and socio‐economic condition of a particular watershed. Previous erosion studies focused on the use of soil erosion models (e.g. USLE, EUROSEM, SLEMSA etc.), which have been developed under local conditions (e.g. United States, Europe, Africa, etc) and mostly use only biophysical factors as inputs to the models. In this study, a methodology that integrates both biophysical and socio‐economic aspects into a framework for soil erosion hazard assessment using principal component analysis (PCA) is described. The analysis is done at the land unit level. With the particular conditions of the study area that is characterized by Inceptisols and Alfisols soil types, nine different land uses with mixed vegetation and forest area dominant in the steep slope, high annual rainfall (>2500 mm), high population with mostly low income and low education, were considered. These were used in formulating a soil erosion hazard index (EHI) equation which relates a number of key factors consisting of biophysical and socio‐economic variables, namely soil texture, slope steepness, land cover, soil conservation practices, income and farmers' knowledge. Weighting and scoring of these key factors were used to develop the EHI equation and to calculate an index value of erosion hazard for every land unit. Results indicate that more than 60% of the area has erosion hazard ranging from moderate to very severe, and most of the land units with high erosion hazard were found at the mountain areas. It was also found that erosion hazard was severe in areas with high silt content, followed by high rainfall and steep slope, low crop cover without any soil conservation practices coupled with lack of awareness on soil erosion and low income. The key factors identified and level of erosion hazard obtained can be used to formulate conservation measures in critical areas which are prone to soil erosion. Copyright © 2007 John Wiley & Sons, Ltd.
Bienzymatic Supramolecular Complex of Catalase Modified with Cyclodextrin‐Branched Carboxymethylcellulose and Superoxide Dismutase: Stability and Anti‐Inflammatory Properties
Authors: Valdivia Aymara , Pérez Yunel , Cao Roberto , Baños Maysa , García Ariel , Villalonga Reynaldo
Published: January 2007

A bienzymatic supramolecular assembly of CAT and SOD is reported. CAT was chemically glycosilated with CD branched CMC and then associated with SOD modified with 1‐adamantane carboxylic acid. SOD was remarkably resistant to inactivation by H2O2 and its anti‐inflammatory activity was 4.5‐fold increased after supramolecular association with the modified CAT form.

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Thermoresponsive Self‐Assembly of Short Elastin‐Like Polypentapeptides and Their Poly(ethylene glycol) Derivatives
Authors: Pechar Michal , Brus Jiří , Kostka Libor , Koňák Čestmír , Urbanová Martina , Šlouf Miroslav
Published: January 2007

Short polypeptides with four pentad repeats, (VPGVG)4 and (VPAVG)4, were synthesised by manual fluorenylmethoxycarbonyl/tert‐butyl (Fmoc/t‐Bu) solid phase peptide synthesis using a convergent approach. In the next step, the peptides were coupled via their N‐terminus with activated semi‐telechelic poly(ethylene glycol) O‐(N‐Fmoc‐2‐aminoethyl)‐O′‐(2‐carboxyethyl)undeca(ethylene glycol) (Fmoc–PEG–COOH) to yield monodisperse Fmoc‐PEG‐peptide diblock copolymer. Both the presence of the terminal hydrophobic Fmoc group and the hydrophilic PEG chain in the copolymers were shown to play a crucial role in their self‐associative behaviour, leading to reversible formation of supramolecular thermoresponsive assemblies. The peptides and their PEG derivatives were characterised by HPLC, NMR and MALDI‐TOF MS. The associative behaviour of the peptides and their PEG derivatives was studied by dynamic light scattering, MAS NMR and phase contrast microscopy.

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Blue Emission of a Soluble Poly(p‐phenylene) with a Cross‐Conjugated Bisimidazole‐Based Chromophore
Authors: Dierschke Frank , Müllen Klaus
Published: January 2007

A novel poly(p‐phenylene) (6) has been synthesized by a cruciform combination of a polyphenylene backbone with 2,2′‐(p‐phenylene)‐bis(4,5‐diphenylimidazole) (5) as an additional, orthogonal chromophore. Polymer 6 showed in solution and in the solid state, a blue‐green emission, which is obviously arising from the second bisimidazole‐based chromophore. UV‐Vis spectroscopy, and cyclic voltammetry revealed that the optical and electronic properties of 6 were fully determined by the incorporated 2,2′‐(1,4‐phenylene)bisimidazole structure. The bisimidazole unit led to high solubility and, despite the steric demand of the substituents, at the same time to the blue‐green emission of the poly(p‐phenylene) (6). In addition, the oxidation of 6 with potassium ferricyanide yielded a low bandgap polymer with a quinoid‐type structure and a bandgap of 1.6 eV.

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Surfactant Chain Length and Tensile Properties of Calcium Carbonate‐Polyethylene Composites
Authors: Osman Maged A. , Atallah Ayman
Published: January 2007

Micron‐sized CaCO3 particles free of milling additives were coated with a monolayer of aliphatic carboxylic acids of different chain length (C2, C4, C5, C10, and C18). CaCO3 was compounded with LDPE at different loading, and the tensile properties of the composites were measured and correlated to the length of the alkyl chains tethered to the particles' surface. SEM indicated that the particles are well dispersed (no agglomerates). The inclusions show little influence on the polymer crystallization, and the filler surface treatment leads to a slight decrease in polymer crystallinity that grows with increasing chain length of the fatty acid. The tensile modulus, yield stress, and maximum stress increase with increasing filler volume fraction ϕ, and the dependence is a function of the length of the alkyl chains tethered to the CaCO3 surface. It seems that the interphase thickness and properties depend on the alkyl chain length and strongly influence the modulus and stresses measured. With increasing chain length in the coated organic layer, the interfacial adhesion between the inclusions and the polymer matrix decreases, and the fibril formation increases. The tensile properties are the result of a superimposition of all these effects. The yield and ultimate strains are dominated by the interfacial slippage (increases with growing alkyl chain length) that leads to debonding at high deformations. Surface treatment of CaCO3 with valeric acid leads to the maximum possible tensile modulus, yield stress, and tensile strength combined with a relatively small loss in yield and ultimate strain.

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Cover Picture: Macromol. Chem. Phys. 1/2007
Authors: Osman Maged A. , Atallah Ayman
Published: January 2007

Cover: Organic monolayer coated on a filler surface does not only hinder particle agglomeration but also influences the mechanical properties of a polymer composite. The length of the alkyl chains of the surfactant molecules can be chosen to tune the composite tensile properties. The figure shows SEM micrographs of tensile samples of LDPE‐CaCO3 composites, untreated and treated with stearic acid (inset). Further details can be found in the Full Paper by M. A. Osman* and A. Atallah on page 87.
Reaction Kinetics and Phase Transformations During Cure of a Thermoplastic‐Modified Epoxy Thermoset
Authors: Varley Russell J.
Published: January 2007

A comprehensive thermal and rheological characterisation of a commercially important aerospace resin system modified with a thermoplastic toughener is presented here. The primary focus has been the understanding of how the cure kinetics and mechanism relate to other processes such as phase separation during cure. Differential scanning calorimetry has shown that thermoplastic modification does not affect the cure mechanism significantly and that the process was dominated by an autocatalytic process up to vitrification after which diffusion‐controlled processes dominate regardless of thermoplastic concentration. Thermoplastic addition at 10 wt.‐% PEI was found to increase the final cure conversion compared with the neat resin and inhibit the onset of diffusion control below a cure temperature of 160 °C. At 20 wt.‐% PEI concentration the final conversion and the onset of diffusion control were similar until 150 °C, after which they displayed lower values than the neat resin. Rheological analysis showed that the phase separation process could be followed conveniently through the changes in viscosity and exhibited effects consistent with expected variations in morphology. The 10 wt.‐% PEI system displayed abrupt increases in viscosities which were indicative of a dispersed particulate morphology, while the 20 wt.‐% PEI system displayed more complex behaviour consistent with a phase‐inverted or co‐continuous structure. The gelation process was shown to obey a power law model although the local environment or morphology of the reactive epoxide group at higher PEI concentrations was shown to affect the fit to the model.

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Novel Nanosized Aluminium Carboxylates: Synthesis, Characterization and Use as Nanofillers for Protective Polymeric Coatings
Authors: Gläsel Hans‐Jürgen , Hartmann Eberhard , Wennrich Luise , Höche Thomas , Buchmeiser Michael R.
Published: January 2007

A mixture of novel aluminium carboxylate nanoparticles and aluminium hydroxide ultrafine powder was prepared via precipitation reaction between Al(2‐PrO)3 and maleic acid. In this mixture both free primary particles occur (mean geometrical size around 40 nm) together with a secondary agglomerated particle fraction of sizes in the low micrometer region. However, centrifugation processes allowed for the removal of the latter and resulted in the formation of size stable nanopowders. Up to 30 wt.‐% of these particles were incorporated into acrylate matrices resulting in low‐viscosity formulations with [η] < 1 000 mPa · s, which allowed for roller application and even spray coating of these nanocomposites at room temperature. Radiation curing of such coatings was accomplished via UV irradiation. In comparison to the corresponding SiO2‐based nanocomposites and carboxylate alumoxane fillers, the cured coatings revealed significantly improved surface mechanical properties.

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Fabrication of Highly Photoluminescent TiO2/PPV Hybrid Nanoparticle‐Polymer Fibers by Electrospinning
Authors: Wang Cheng , Yan Eryun , Huang Zonghao , Zhao Qiang , Xin Yi
Published: January 2007

In this study, we have synthesized highly photoluminescent TiO2/poly (phenylene vinylene) (PPV) hybrid nanoparticle‐polymer fibers by electrospinning a PPV precursor added to a TiO2 sol‐gel solution. The diameters of the hybrid fibers ranged from 100–300 nm and the average size of TiO2 nanoparticles within the fibers was 10–60 nm. FT‐IR analysis indicated that a new band around 1 632 cm−1 assigned to the TiOC vibration appeared, which resulted in the stronger luminance of the fluorescence of the TiO2/PPV hybrid fibers compared to free standing PPV nanofibers.

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Direct Observation of α‐Chloro‐p‐quinodimethane as the Real Monomer in the Gilch Polymerization Leading to Poly(p‐phenylene vinylene)s
Authors: Wiesecke Jens , Rehahn Matthias
Published: January 2007

It is the general consensus that in Gilch polymerizations the 1,4‐bis(chloromethylene)benzene starting material first changes into p‐quinodimethane intermediates which then act as the real monomers. However, direct observation of these intermediates has not been possible so far. This is because usually the p‐quinodimethane auto‐initiates its rapid radical polymerization instantaneously, keeping its concentration extremely low throughout the whole process. Here it is shown that, when the reaction is carried out at very low temperatures, the formation of p‐quinodimethane still proceeds but chain growth is suppressed. Hence, the concentration of the active monomer reaches a level sufficient for NMR analysis.

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Polyelectrolytes Revisited: Reliable Determination of Intrinsic Viscosities
Authors: Wolf Bernhard A.
Published: January 2007

The linear extrapolation of (η − η0)/(η0c) towards c → 0 constitutes the basis of traditional methods to determine intrinsic viscosities [η], where η is the viscosity of polymer solutions of concentration c and η0 is the viscosity of the pure solvent. With uncharged macromolecules this procedure works well; for polyelectrolytes it fails because of the pronounced non‐linearity of the above dependence at high dilution resulting from the increasing electrostatic interactions. This contribution presents a new method for the determination of [η]. It rests upon the application of the laws of phenomenological thermodynamics to the viscosity of polymer solutions and introduces a generalized intrinsic viscosity enabling a comparison of differently charged and uncharged polymers.

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A Novel, One‐Pot Synthesis of Novel 3F, 5F, and 8F Aromatic Polymers
Authors: Diaz Adan M. , Zolotukhin Mikhail G. , Fomine Serguei , Salcedo Roberto , Manero Octavio , Cedillo Gerardo , Velasco Victor M. , Guzman Maria T. , Fritsch Detlev , Khalizov Alexei F.
Published: January 2007

A series of novel, linear, soluble, high‐molecular‐weight, fluorinated aromatic polymers has been obtained for the first time using a superacid‐catalyzed polyhydroxyalkylation reaction of fluorinated carbonyl‐containing compounds: 1,1,1,‐trifluoroacetone (1), 2,2,2‐trifluoroacetophenone (2), 2,3,4,5,6,‐pentafluorobenzaldehyde (3), and octafluoroacetophenone (4) with aromatic hydrocarbons such as biphenyl (a), phenyl ether (b), terphenyl (c), and 4,4′‐diphenoxybenzophenone (d). These Friedel‐Crafts‐type aromatic electrophilic substitution reactions are performed at room temperature in trifluoromethane sulfonic acid or in its mixtures with dichloromethane. The polymers obtained are soluble in common organic solvents, and colorless transparent films could be cast from the solutions. 1H and 13C NMR analyses of the polymers synthesized reveal their linear, highly regular structure. The polymers also possess high thermostability.

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Control of SWNT Dispersion by Block Copolymers with a Side‐Chain Polarity Modifier
Authors: Sung Jinwoo , Park Jae Man , Choi U‐Hyeok , Huh June , Jung Bumsuk , Min Byung Gil , Ahn Cheol Hee , Park Cheolmin
Published: January 2007

The dispersion of single‐walled carbon nanotubes (SWNTs) in a non‐polar solvent is controlled with a series of polystyrene‐block‐polybutadiene‐block‐polystyrene (PSBS) block copolymers that contain cholesteryl chloroformate (CC) in side‐chains. Esterification of CC with the partially hydroxylated polybutadiene (PB) blocks allows one to tune the polarity of the block copolymers, which decreases with the amount of CC attached. An excellent dispersion of weak polar SWNTs is observed with PSBS that contains a partially hydroxylated PB block. The dispersion is then significantly deteriorated when the amount of non‐polar CC moieties increases in the block copolymers. A good dispersion is achieved with a polymer that gives rise to strong SWNT–polymer interactions, which ensures contact of the polymer molecules with the nanotube surface, rather than a good solubility of the polymer dispersant in solvent. The stability of the SWNTs in solution arises from unique needle‐like nanowires of the block copolymer aligned perpendicular to the nanotube axis.

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