bluuebunny/crossref_metadata_2025 huggingface dataset:
The health and life experiences of mothers with rheumatoid arthritis: A phenomenological study
Authors: Mitton Debbie L. , Treharne Gareth J. , Hale Elizabeth D. , Williams Robert A. , Kitas George D.
Published: September 2007

Background: In our varied roles as health care professionals and researchers, many women with rheumatoid arthritis (RA) have commented to us about their feelings of inability to cope with everyday tasks, especially within their role as mothers.

Aims: This study explored the health and life experiences of mothers with RA in order to increase knowledge about this group of women and inform health care professionals who provide them with support before and after becoming a mother.

Methods: A phenomenological approach was adopted, and individual face‐to‐face semi‐structured interviews were carried out with a sample of seven women, aged 21–41 years, who had lived with RA for 3–11 years and had one or more children under five years of age (total range of ages being 1–7 years). The data were analysed using Colaizzi's procedural steps.

Results: The five major themes that emerged were inner strength, depression, labelling, failure, and pre‐ and post‐natal education. Sub‐themes included issues such as putting on a brave face, spirituality, guilt, burden, feeling ‘robbed of motherhood’, isolation, coping methods and lack of information.

Conclusions: This in‐depth study informs health care professionals for their role as support provider for mothers with RA. Further research needs to be carried out to include multicultural experiences, which may or may not differ. As a step forward, we have implemented a local support group for mothers with RA, which will hopefully add benefit to existing rheumatology, midwifery and health visiting services. Copyright © 2007 John Wiley & Sons, Ltd.
Comparison between iterative solution of symmetric and non‐symmetric forms of Biot's FEM equations using the generalized Jacobi preconditioner
Authors: Toh Kim‐Chuan , Phoon Kok‐Kwang
Published: September 2007

Finite element discretization of Biot's consolidation equations can produce a symmetric indefinite system (commonly used in geomechanics) or a non‐symmetric system. While this difference appears to be minor, however, it will require the selection of entirely different Krylov subspace solvers with potentially significant impact on solution efficiency. The former is solved using the symmetric quasi‐minimal residual whereas the latter is solved using the popular bi‐conjugate gradient stabilized. This paper presents an extensive comparison of the symmetric and non‐symmetric forms by varying the time step, size of the spatial domain, choice of physical units, and left versus left–right preconditioning. The generalized Jacobi (GJ) preconditioner is able to handle the non‐symmetric version of Biot's finite element method equation, although there are no practical incentives to do so. The convergence behaviour of GJ‐preconditioned systems and its relation to the spectral condition number or the complete spectrum are studied to clarify the concept of ill‐conditioning within the context of iteration solvers. Copyright © 2007 John Wiley & Sons, Ltd.
Psychometric evaluation of the arabic language version of the profile of Mood States
Authors: Aroian Karen J. , Kulwicki Anahid , Kaskiri Eleni A. , Templin Thomas N. , Wells Charles L.
Published: September 2007

We estimated the psychometrics of the parent and a short form of the Arabic language version of the Profile of Mood States (POMS). A sample of 537 Arab immigrants completed the POMS and a battery of other measures. Data analyses included confirmatory factor analyses and tests of reliability and concurrent validity. The fit of the proposed factor structure was acceptable if 14 pairs of error terms were allowed to correlate, but a better fit was obtained by creating a short form. The short form demonstrated good reliability and concurrent validity, but some factors were highly correlated. High factor correlations were not explainable by group differences in education or level of distress. © 2007 Wiley Periodicals, Inc. Res Nurs Health 30:531–541, 2007
Care‐seeking behaviors of African American women with breast cancer symptoms
Authors: Reifenstein Karen
Published: September 2007

In this descriptive correlational study, 48 African American women were assessed for delay in care‐seeking for breast cancer symptoms by examining: (a) relationships between selected psychosocial variables (fear, denial, utility, and social norm) and delay, (b) relationships between delay and having an identified health provider, affordable health care services, and accessible health‐care services, (c) whether denial would mediate the effect of fear on delay, (d) whether utility would moderate the effects of social norm and facilitating conditions on delay, and (e) whether denial was related to escape‐avoidance coping. Participants completed mailed questionnaires. Pearson correlation and separate regression analyses showed that denial was associated with increased delay. Confrontive coping, social support, and problem‐solving strategies had no relationship with delay. Interventions focusing on denial could help enhance early care seeking. © 2007 Wiley Periodicals, Inc. Res Nurs Health 30:542–557, 2007
Microsatellite unstable colorectal cancer cell lines with truncating TGFβRII mutations remain sensitive to endogenous TGFβ
Authors: Baker K , Raut P , Jass JR
Published: September 2007

Disruptions to the TGFβ signalling pathway have been implicated in most human adenocarcinomas. As cancers progress, many acquire resistance to the growth‐suppressing properties of TGFβ while retaining sensitivity to its tumour‐promoting effects. Microsatellite unstable colorectal cancers (MSI‐H CRCs) possess truncating mutations in the type II TGFβ receptor (TGFβRII) gene that have been assumed to render these tumours insensitive to TGFβ. However, numerous reports of TGFβRII bypass exist and this study was thus undertaken in order to clarify the true extent of TGFβ sensitivity in MSI‐H CRCs. Using stimulation with exogenous TGFβ, we demonstrated that, while MSI‐H CRCs are capable of binding soluble TGFβ, two out of three cell lines examined remain refractory to its signalling effects. In contrast, use of a specific inhibitor of the type I TGFβ receptor (TGFβRI) revealed that all remain sensitive to signalling by endogenously produced TGFβ. Specifically, autocrine signalling via TGFβRI mediates constitutive activation of Smad2 as well as repression of Erk signalling. Real‐time PCR confirmed that these effects are sufficient to affect the expression level of various TGFβ‐modulated genes. An invasion assay revealed that autocrine TGFβRI signalling also promotes the invasion capacity of MSI‐H CRCs to an extent similar to that seen in their non‐MSI‐H counterparts. Independent TGFβRI signalling, however, has no effect on the rate of proliferation of MSI‐H CRC cells. Together, these results demonstrate that MSI‐H CRC cell lines are not completely refractory to TGFβ, despite lacking functional TGFβRII. In addition to clarifying the true consequences of natural TGFβRII loss and the independent function of TGFβRI, our results highlight the selective nature of TGFβ resistance developed by cancers. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Evaluation of spectrophotometric methods for screening of green rooibos (Aspalathus linearis) and green honeybush (Cyclopia genistoides) extracts for high levels of Bio‐active compounds
Authors: Joubert Elizabeth , Manley Marena , Botha Mariza
Published: September 2007

The potential of UV spectrophotometry and an aluminium chloride (AlCl3) colorimetric method to determine the dihydrochalcone (DHC) and mangiferin contents of green rooibos and honeybush (C. genistoides) extracts, respectively, was investigated. The DHC content of rooibos water extracts, determined using UV spectroscopy, correlated with the sum of the aspalathin and nothofagin contents as quantified using HPLC (r = 0.98). A correlation coefficient of 0.91 was obtained when correlating the mangiferin content of C. genistoides methanol extracts, determined by the AlCl3 colorimetric method, with the results obtained by HPLC. Using the linear equations from the correlations it was possible to predict the DHC and mangiferin contents of extracts from the respective spectrophotometric measurements to a reasonable accuracy as an alternative to HPLC. The total polyphenol (TP) content of rooibos water extracts can also be determined using UV spectrophotometry and aspalathin as a standard (r = 0.99) as an alternative to the Folin–Ciocalteau method. The TP content of rooibos extracts correlated (r = 0.99) with its total antioxidant activity (TAA) as determined with the ABTS radical cation scavenging assay, but the TP content of C. genistoides water extracts is not a good indication of their TAA (r = 0.27). The aspalathin content of rooibos extracts correlated with their TAA (r = 0.96), but the mangiferin content of honeybush water extracts only gave a moderate correlation with their TAA (r = 0.75). Copyright © 2007 John Wiley & Sons, Ltd.
Localized effects of dynamic melt manipulation on flow induced orientation and mechanical performance of injection molded products
Authors: Layser Gregory S. , Coulter John P.
Published: September 2007

This study investigates the effects that dynamic melt manipulation based injection molding has on the locally induced molecular orientation and tensile strength of injection molded polystyrene. Melt manipulation refers to a process where the polymer melt is manipulated during molding beyond the extent normally encountered in conventional injection molding. The specific melt manipulation process investigated in this article is vibration assisted injection molding, where a conventional injection molding machine is augmented by oscillating the injection screw (in the axial direction) during the injection and packing phases of the molding cycle. The localized final molecular orientation and morphology that results dictates the resultant product response, and typically improved mechanical properties are observed. Specimens with molecular orientation distributed more uniformly along the gage length typically exhibited higher tensile strength than samples with a gradient of orientation along the gage length. Smaller test specimens machined along the gage length of larger molded specimens showed dramatic tensile strength increase in the regions of higher melt manipulation, further supporting the promise of this novel processing methodology. POLYM. ENG. SCI., 47:1912–1919, 2007. © 2007 Society of Plastics Engineers
Influence of epoxy resin on the morphological and rheological properties of PBT/ABS blends compatibilized by ASMA
Authors: Yao Zengzeng , Lin Mei , Zhou Jing , Wang Haitao , Zhong Wei , Du Qiangguo
Published: September 2007

Polybutylene terephthalate (PBT)/acrylonitrile–butadiene–styrene (ABS) copolymer blends compatibilized by a mixture of styrene–acrylonitrile–maleic anhydride (ASMA) copolymers and epoxy resin (EP) were prepared through melt reactive extrusion. The morphological, rheological, and mechanical properties of these blends were studied. The epoxy functional groups of EP can react with anhydride groups of ASMA and the PBT terminal groups (OH and COOH) simultaneously, leading to the formation of ASMA–EP–PBT graft copolymers. Because of the effective compatibilization of these copolymers at the interface, finer dispersed phase morphologies were obtained. Compared with PBT/ABS/ASMA blends, the addition of EP induced a more stable molten phase structure, with increases of storage moduli, loss moduli, and dynamic viscosities. Results indicated that 1.5 wt% of the EP in the blends was most suited for the compatibilization. Impact properties of these blends were also investigated. POLYM. ENG. SCI., 47:1943–1950, 2007. © 2007 Society of Plastics Engineers
Development of BIATECH‐54 standard mixtures for assessment of protein identification and relative expression
Authors: Kolker Eugene , Hogan Jason M. , Higdon Roger , Kolker Natali , Landorf Elizabeth , Yakunin Alexander F. , Collart Frank R. , van Belle Gerald
Published: September 2007

Mixtures of known proteins have been very useful in the assessment and validation of methods for high‐throughput (HTP) MS (MS/MS) proteomics experiments. However, these test mixtures have generally consisted of few proteins at near equal concentration or of a single protein at varied concentrations. Such mixtures are too simple to effectively assess the validity of error rates for protein identification and differential expression in HTP MS/MS studies. This work aimed at overcoming these limitations and simulating studies of complex biological samples. We introduced a pair of 54‐protein standard mixtures of variable concentrations with up to a 1000‐fold dynamic range in concentration and up to ten‐fold expression ratios with additional negative controls (infinite expression ratios). These test mixtures comprised 16 off‐the‐shelf Sigma–Aldrich proteins and 38 Shewanella oneidensis proteins produced in‐house. The standard proteins were systematically distributed into three main concentration groups (high, medium, and low) and then the concentrations were varied differently for each mixture within the groups to generate different expression ratios. The mixtures were analyzed with both low mass accuracy LCQ and high mass accuracy FT‐LTQ instruments. In addition, these 54 standard proteins closely follow the molecular weight distributions of both bacterial and human proteomes. As a result, these new standard mixtures allow for a much more realistic assessment of approaches for protein identification and label‐free differential expression than previous mixtures. Finally, methodology and experimental design developed in this work can be readily applied in future to development of more complex standard mixtures for HTP proteomics studies.
Proteome, salicylic acid, and jasmonic acid changes in cucumber plants inoculated with Trichoderma asperellum strain T34
Authors: Segarra Guillem , Casanova Eva , Bellido David , Odena Maria Antonia , Oliveira Eliandre , Trillas Isabel
Published: September 2007

Trichoderma spp. is one of the most commonly used biological control agents against plant pathogens. This fungus produces changes in plant metabolism, thus increasing growth and enhancing resistance to biotic and abiotic stresses. However, its modes of action remain to be defined. In the first hours of interaction between cucumber plant roots and Trichoderma asperellum strain T34, salicylic and jasmonic acid levels and typical antipathogenic peroxidase activity increase in the cotyledons to different degrees depending on the applied concentration of the fungi. The use of 2‐DE protein profiling and MS analysis allowed us to identify 28 proteins whose expression was affected in cotyledons after cucumber root colonization by Trichoderma applied at high concentrations: 17 were found to be up‐regulated while 11 were down‐regulated. Proteins involved in ROS scavenging, stress response, isoprenoid and ethylene biosynthesis, and in photosynthesis, photorespiration, and carbohydrate metabolism were differentially regulated by Trichoderma. The proteome changes found in this study help to give an understanding of how Trichoderma‐treated plants become more resistant to pathogen attacks through the changes in expression of a set of defence‐oriented proteins which can directly protect the plant or switch the metabolism to a defensive, nonassimilatory state.
Why colchicine does not show mutarotation. With M05‐2X density functional in the realm of tricky natural products
Authors: Pietra Francesco
Published: September 2007

It is shown here that density functional theory (DFT) calculations with the recent M05‐2X hybrid functional correctly reproduced the conformation of, and energy difference between, (Ra,7S)‐ and (Sa,7S)‐type atropisomers of isocolchicine. Interconversion of these 1H NMR‐observable atropisomers accounts for mutarotation with this compound. In contrast, the classical B3LYP hybrid functional failed to simulate satisfactorily both the geometries and the energies involved. This extends the use of M05‐2X to natural products that embody aromatic and flexible pseudoaromatic and saturated rings, as well as cis/trans amide chains, which bring on subtle conformational problems. DFT calculations with M05‐2X also shed new light on a long‐date conundrum in organic chemistry and pharmacology, i.e., why mutarotation was never observed with colchicine. This is now best attributed to a larger energy gap between the (Ra,7S) atropisomer and the elusive (Sa,7S) atropisomer with this compound. These results solicit a rethinking of the interactions between colchicinoids and proteins. Copyright © 2007 John Wiley & Sons, Ltd.
Focused ion beam micromachining and computation of polymeric photonic band gap
Authors: Pialat E. , Trigaud T. , Moliton J. P. , Thévenot M.
Published: September 2007

This article introduces a new approach to the achievement of low cost devices for optical telecommunications. For this purpose, the implementation of polymer components and of the WDM method show several advantages. A polymeric photonic band gap lattice can effectively assume demultiplexing at the wavelength of 1.55 μm without energy dissipation. First, the computation of the geometrical parameters designing a polymer photonic crystal by means of the finite‐difference‐time‐domain method, implemented with Bloch functions, is presented here. Second, the achievement of 2D polymer lattices by a dry process, the focused ion beam milling, is exposed. The experimental conditions for the achievement of a master are discussed on the basis of the milling performances and of the polymers physical properties. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2993–3002, 2007
Cure temperature influence on natural rubber—A small angle X‐ray scattering study
Authors: Salgueiro W. , Somoza A. , Torriani I. L. , Marzocca A. J.
Published: September 2007

To analyze the natural rubber behavior during vulcanization under different cure treatments, an experimental investigation using small angle X‐ray scattering was performed. To achieve this, a set of samples were prepared using sulfur and N‐t‐butyl‐2‐benzothiazole sulfenamide as accelerator and then cured at temperatures between 403 and 463 K reaching their optimum mechanical properties considering rheometer tests. The crosslink density of the samples was evaluated by means of the swelling technique in solvent. In the usual Lorentz corrected representation of the X‐ray scattered intensity, a maximum was observed in the plots corresponding to the cured samples, revealing a highly correlated structure. This maximum shifted toward higher values of the scattering vector when the cure temperature of the samples increased. This behavior is discussed in terms of the crosslinks type present in the vulcanized rubber network at different cure temperatures. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2966–2971, 2007
Plasma Processing of Propane at Hyper‐Atmospheric Pressure: Experiment and Modelling
Authors: Hill Sarah L. , Whitehead J. Christopher , Zhang Kui
Published: September 2007

A dielectric packed‐bed plasma reactor was used for the destruction of propane in air and was successfully created and maintained at higher than atmospheric pressure (3 bar). The effects of pressure, REF and SED on propane removal and NOx production are discussed. An increase in SED enhances propane destruction and increases NOx production. Increasing the pressure to 3 bar produces a more efficient removal process with an energy of 877 and 600 eV per molecule at 1 and 3 bar, respectively. The pressure increase also altered the ratio of NO2 to NO produced from ≈1 to >3, showing that substantially more NO2 than NO is produced in a 3 bar air discharge.

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Early intervention in CF: How to monitor the effect
Authors: Weiser Giora , Kerem Eitan
Published: September 2007

Early and aggressive therapy already at the stage when no apparent signs of significant lung disease are detectable, may delay the development and progression of cystic fibrosis (CF). Identification of markers for early pulmonary disease in CF is crucial to monitor adherence to preventive therapy and determine its success. Currently several surrogate markers are available that are used in both the decision making and evaluation of the timing and success of early intervention namely, pulmonary function tests (PFT), microbial cultures, imaging techniques, inflammatory markers, serological markers, and several general signs such as exacerbation rate and nutritional status. This review will present the current status and discuss the significance of their application as well as their limitations for patients with CF and no apparent pulmonary disease. 2007;42:1002–1007. © 2007 Wiley‐Liss, Inc.
Reliability of antibodies to Candida methionine synthase for diagnosis, prognosis and risk stratification in systemic candidiasis: A generic strategy for the prototype development phase of proteomic markers
Authors: Pitarch Aida , Nombela César , Gil Concha
Published: September 2007

To be able to diagnose systemic candidiasis (SC) and to predict outcomes in SC patients are still challenging tasks for physicians. Previous proteomic studies suggest that anti‐Candida methionine synthase (Met6p) IgG antibodies may be a candidate marker for SC. To evaluate their reliability for diagnosis, prognosis and risk stratification in SC, we developed a generic prototype strategy for their measurement in SC. Receiver‐operating‐characteristic curve analyses revealed a high diagnostic accuracy for this prototype format, which was slightly better to that for the widely used Western blot assays. Multivariate logistic‐regression models showed a positive association between serum anti‐Met6p IgG antibody levels and SC risk that was independent from established SC risk factors and other baseline variables. After adjusting for and stratifying according to known prognostic factors, a significant trend toward a lower two‐month mortality risk with increasing levels was evidenced in SC patients at presentation. We conclude that these antibodies may be useful in discriminating SC from non‐SC patients and determining risk stratification in SC. These may also confer protection against SC and be valuable for the design of future immunotherapies. Furthermore, our prototype format has the potential to make impact on other infectious diseases, cancers, allergies or autoimmune disorders.
Imidacloprid mobility and longevity in soil columns at a termiticidal application rate
Authors: Peterson Chris J
Published: September 2007

The mobility, longevity and termiticidal activity of imidacloprid (Premise® 2 termiticide; Bayer Environmental Sciences) at the termiticidal labeled rate for perimeter treatment were tested in vegetated and non‐vegetated soil columns in two tests: in cone plots and in polyvinyl chloride (PVC) pipes. Imidacloprid content in the cone plot eluate peaked at 1 month, declined rapidly by the second month and then entered a lagging phase. The concentration of imidacloprid in the cone plot soil declined from 84.5 µg g−1 initially to 7.5 µg g−1 (non‐vegetated plots) and 8.1 µg g−1 (vegetated plots) 6 months later. Neither eluate concentration nor soil concentration was affected by the presence of vegetation in the cone plots. In the PVC pipes, the top 15 cm of which was treated with Premise® 2 at the perimeter labeled rate, imidacloprid half‐life was estimated at 6–9 months for vegetated and non‐vegetated soil. Extractable imidacloprid declined more rapidly in the first 15 months than afterwards. Mobility of imidacloprid into lower, untreated soil depths was higher in non‐vegetated pipes, and was likely due to the effect of vegetation on soil moisture. The presence of vegetation had little effect on the termiticidal activity of treated soil in the PVC pipes. Published in 2007 by John Wiley & Sons, Ltd.
The potential environmental impact of pesticides removed from sprayers during cleaning
Authors: Ramwell Carmel T , Leak Jennifer , Cooper Simon E , Taylor William A
Published: September 2007

BACKGROUND: There is concern that pesticide residues on the external surfaces of sprayers could have an adverse impact on the environment if they are washed off, yet there is a need to remove these residues for health reasons. The aim of this study was to quantify pesticide residues contained in washings from cleaning discrete parts of a sprayer and to assess their likely environmental impact.

RESULTS: The boom/rear of the sprayer and the spray tank accounted for 80% of the total pesticide load in the washings. Predicted environmental pesticide concentrations from sprayer washings were lower than predictions from the FOCUS surface water model for pesticides used under normal agricultural conditions, although for tebuconazole this difference was smaller than for the other compounds investigated. The field area over which the residues may need to be uniformly deposited to avoid overdosing during infield cleaning was typically less than 0.5 m2, with a maximum value of 4 m2.

CONCLUSIONS: It is unlikely that infield cleaning will lead to overdosing. External residues are not insignificant, so any adverse impact on the environment must be mitigated. Appropriate measures include cleaning in the field away from surface waters and other sensitive areas, and cleaning machines over bunded areas or similar. © Crown copyright 2007. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
Glycosylated foldamers: synthesis of carbohydrate‐modified β3hSer and incorporation into β‐peptides
Authors: Norgren Anna S. , Norberg Thomas , Arvidsson Per I.
Published: September 2007

Fmoc‐protected β3hserine (β3hSer) was prepared and O‐linked to suitably protected N‐acetylgalactosamine (GalNAc) and N‐acetylglucosamine (GlcNAc) derivatives. Glycosylation of β3hSer was made by two independent routes: either by direct glycosyl linkage to the β3hSer, or linkage to natural L‐Ser and then utilizing the carbohydrate moiety as a protecting group in an Arndt–Eistert homologation. Both procedures gave the novel glycosylated β3‐amino acids Fmoc‐β3hSer(α‐D‐GalNAc(Ac)3)‐OH (1a), its β‐anomer (1b), and Fmoc‐β3hSer(β‐D‐GlcNAc(Ac)3)‐OH (2), which were utilized in the solid‐phase peptide synthesis of four glycosylated dipeptides (3a–d) and two heptapeptides (4a–b). The preparation of β‐amino acids bearing common post‐translational modifiers represents an important step towards functionalized foldamers with broad applications in biomedical research. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Validation of a solid‐phase‐bound steroid scaffold for the synthesis of novel cyclic peptidosteroids
Authors: Bodé Catherine A. , Muller Claude P. , Madder Annemieke
Published: September 2007

The current article reports on the synthesis of a new type of cyclic peptidosteroid, in which a bile‐acid‐based scaffold was used for the conformational restriction of a loop‐like peptide. Convergent coupling of two tetrapeptides to the non‐peptidic steroidal entity was carried out once in the classical C‐to‐N and once in the non‐classical N‐to‐C direction. Peptide backbone cyclisation was then carried out, giving rise to a ring size equivalent to approximately 12 amino acids. This type of construct will be used in the development of a peptide vaccine against measles. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Robert Robinson and penicillin: an unnoticed document in the saga of its structure
Authors: Curtis Rachel , Jones John
Published: September 2007

A description and commentary is given for an unnoticed sheet of formulae and arguments in the hand of Robert Robinson concerning the structure of penicillin. In this undated document, probably of Autumn 1944, he set out his arguments for favouring a thiazolidine‐oxazolone structure over the actual β‐lactam structure. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Hepta and octapeptide agonists of protease‐activated receptor 2
Authors: Devlin Mark G. , Pfeiffer Bernhard , Flanagan Bernadine , Beyer Renée l. , Cocks Thomas M. , Fairlie David P.
Published: September 2007

Protease‐activated receptor 2 (PAR2) is a G protein‐coupled cell surface receptor for trypsin‐like enzymes. Proteolytic cleavage at a specific site in the extracellular N‐terminus exposes a receptor‐activating sequence, the ‘tethered ligand’, which binds intramolecularly to initiate receptor signalling. Peptide or small molecule agonists for PAR2, devoid of the non‐specific and proteolytic effects of enzyme activators, may be promising therapeutic agents for proliferative and inflammatory diseases reportedly mediated by PAR2. Synthetic hexapeptides that correspond to the native tethered ligand of human or rodent PAR2 (SLIGKV and SLIGRL, respectively) can activate the receptor independently of proteolytic cleavage; however, known peptide agonists have much lower potency compared to protease‐mediated activation. Here, we investigated the agonist activity of 94 hepta and octapeptide derivatives of the human and rodent PAR2‐tethered ligand sequences in human airway epithelial (A549) cells which endogenously express PAR2. Thirty synthetic peptides were found to be as potent as or more potent than SLIGRL on the basis of intracellular Ca2+ responses. The more active peptide agonists were also examined for agonist cross‐reactivity at PAR1 in Chinese Hamster Ovary (CHO) cells that endogenously express functional PAR1 but not PAR2. Two potent and PAR2‐selective agonists were further examined for their capacity to relax phenylephrine‐contracted rat aortic rings. Our findings reveal an important role for carboxyl extensions to native PAR2 activating peptides in potentiating agonist activity. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Plant signalling peptides: some recent developments
Authors: Bahyrycz Agata , Konopińska Danuta
Published: September 2007

The subject of this review is plant signalling peptides, peptides of a new generation which regulate growth, differentiation, and other plant physiological functions. These peptides include systemin, the phytosulfokines (PSKs), ENOD40, CLAVATA3, Locus‐S, POLARIS, IDA, and ROT4. On the basis of literature data and our own results we discuss their structure, biological properties, and structure/biological function relationship, especially for the more studied systemin and PSK‐α. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Numerical modelling of lasing in microstructures
Authors: Zhukovsky Sergei V. , Chigrin Dmitry N.
Published: September 2007

Two methods suitable for numerical modelling of microlasers (including photonic crystal, microcavity, and random lasers) are presented. Finite‐difference time‐domain (FDTD) method and a generalized coupled mode theory are discussed in the context of microstructured resonators. The cases of one mode and two modes with near‐identical properties but different frequencies are investigated in detail. The predictions of the coupled mode model are compared to FDTD simulations of a microcavity laser based on a single defect and twin coupled defects in a photonic crystal lattice. Different regimes of the mode competition (simultaneous and bistable lasing) are analyzed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Diameter sorting of carbon nanotubes by gradient centrifugation: role of endohedral water
Authors: Hennrich F. , Arnold K. , Lebedkin S. , Quintillá A. , Wenzel Wolfgang , Kappes Manfred M.
Published: September 2007

We demonstrate that water filling has a significant, tube‐diameter dependent effect on the effective mass density of individual single‐walled carbon nanotubes suspended in aqueous suspension. On the basis of extensive molecular dynamics simulations of water‐filled carbon nanotubes we have estimated the number density and properties of water molecules inside different types of nanotubes. As the tube diameter becomes comparable with the size of a water molecule, the number density of water molecules jumps discontinously. For tube diameters just above this threshold the water molecules organize into a single file. Shell‐like arrangements are found for even larger radii. Buoyant densities are predicted to change accordingly. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of the combustible agents on the synthesis of Fe–Mo/MgO catalysts for the production of carbon nanotubes
Authors: Dias Lima Márcio , Jung de Andrade Mônica , Locatteli Andrei , Balzaretti Naira , Nobre Felipe , Perez Bergmann Carlos , Roth Siegmar
Published: September 2007

The production of Fe–Mo/MgO by Solution Combustion Synthesis (SCS) for use as catalysts in single‐walled carbon nanotube (SWNT) synthesis was evaluated. Glycine, urea, citric acid and polyethylene glycol 200 and 400 were tested as combustible agents (CA). Iron and magnesium nitrates and ammonium molybdate were used as catalyst precursors. Four different proportion ratios of combustible/metals salts were tested. The addition of CA greatly effects the morphology and density of the produced catalyst. Carbon nanotubes were evaluated using thermogravimetric analysis, Raman spectroscopy, scanning and transmission electron microscopes and by measuring the electrical conductivity of the carbon nanotubes dispersed in chloroform. The highest absolute carbon yield was obtained with the urea, but carbon nanotubes with higher G/D ratios were produced with glycine as the CA. However, the higher yield of carbon per volume of catalyst was produced using polyethylene glycol. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Solubilization of single‐wall carbon nanotubes in aqueous solutions of calixarenes
Authors: Lobach A. S. , Ryzhkina I. S. , Spitsina N. G. , Obraztsova E. D.
Published: September 2007

The present work reports the studies of the solubilization of single‐wall carbon nanotubes in aqueous solutions of calix[4]resorcinarene derivatives and p‐sulfonato‐calix[n ]arenes (n = 4, 6) modified by alkyl (butyl and dodecyl) substituents. The highest dispersion ability is demonstrated by calix[4]resocinarene, which bears aminomethyl groups on the upper rim and phosphorus‐bearing alkyl fragments on the lower rim of calixarene. Optical absorption spectroscopy justifies the formation of stable suspensions of SWNT in aqueous solutions of calixarenes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical approach to Rayleigh and absorption spectra of semiconducting carbon nanotubes
Authors: Malić Ermin , Hirtschulz Matthias , Milde Frank , Wu Yang , Maultzsch Janina , Heinz Tony F. , Knorr Andreas , Reich Stephanie
Published: September 2007

A microscopic calculation of the Rayleigh scattering cross section and the absorption coefficient for arbitrary single‐walled carbon nanotubes is presented. The approach is based on the density matrix formalism combined with the tight‐binding band structure. Both Rayleigh and absorption spectra show a characteristic intensity ratio behavior, which can be explained by an interplay of the optical matrix element and the joint density of states. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Detail study of the Raman‐active modes in carbon nanotubes
Authors: Mohr M. , Machón M. , Thomsen C. , Milošević I. , Damnjanović M.
Published: September 2007

The Raman‐active A1‐modes in carbon nanotubes are often used for characterizing nanotube samples. The fully‐symmetric radial‐breathing mode and the high‐energy mode (HEM) have small non‐radial and non‐tangential components, respectively. Neglecting these components results in errors for phonon frequency and electron–phonon coupling calculations. We present a model to estimate these non‐radial components. For the HEM we find an anharmonicity that stems from the three‐fold coordination of the C atoms. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling suspended carbon nanotube resonators
Authors: Poot M. , Witkamp B. , Otte M. A. , van der Zant H. S. J.
Published: September 2007

We study the bending mode vibration in suspended carbon nanotubes. Based on the theory of continuum mechanics, we have developed a model for flexural oscillations of suspended nanotubes. A detailed analysis of the electrostatic force, the scaling behavior of the model and the gate tuning is given. The model is used to fit experimental data and to reconstruct the gate dependence of the tension and strain in the nanotube. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis of fullerene dimers with controllable length
Authors: Porfyrakis Kyriakos , Sambrook Mark R. , Hingston Timothy J. , Zhang Jinying , Ardavan Arzhang , Briggs G. Andrew D.
Published: September 2007

Fullerenes have attracted interest as materials for next‐generation electronic devices. Considerable effort has been focused on the chemical functionalization of fullerenes. Fullerene dimers possess interesting photophysical effects. Herein we present an overview of our efforts on the synthesis and characterization of different types of fullerene dimers such as directly bonded dimers, a short chain C60 dimer and other dimers with bridge molecules of varying length. By choosing the bridge‐molecule one can control the interfullerene spacing and thus tune the electronic interaction between the fullerenes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Catalyst size dependencies for carbon nanotube synthesis
Authors: Rümmeli M. H. , Kramberger C. , Schäffel F. , Borowiak‐Palen E. , Gemming T. , Rellinghaus B. , Jost O. , Löffler M. , Ayala P. , Pichler T. , Kalenczuk R. J.
Published: September 2007

We have systematically explored the synthesis parameters in laser evaporation and CVD for the synthesis of carbon nanotubes. Our findings point to a dependence of the resultant tubes on the volume to surface area ratio of the catalyst particle. The data furthers our understanding on the nucleation of carbon nanotubes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Raman imaging for processing and process monitoring for nanotube devices
Authors: Stampfer C. , Bürli A. , Jungen A. , Hierold C.
Published: September 2007

We present a process flow for single‐walled carbon nanotube electronic and electromechanical device fabrication, where the technique of Raman imaging has been used (i) for the fabrication process monitoring itself and (ii) to consequently observe modifications of the integrated nanotubes during processing. First, extended Raman images (i.e. maps) have been used to locate nanotubes relative to reference alignment markers enabling to distinguish semiconducting from metallic carbon nanotubes before electrically contacting them. Second, we used Raman imaging to monitor individual process steps. We show that the radial breathing mode (RBM) signal is very sensitive to standard processes used to contact individual nanotubes. Moreover, we conclude that HF etching for releasing nanotubes leads to a significant increase of the defect‐induced D line. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Infrared spectroscopy on the rotor–stator compounds C60–C8H8 and C70–C8H8 under pressure
Authors: Thirunavukkuarasu K. , Kuntscher C. A. , Bényei Gy. , Jalsovszky I. , Klupp G. , Kamarás K. , Kováts É. , Pekker S.
Published: September 2007

Pressure‐dependent infrared transmittance measurements on C60–C8H8 and C70–C8H8 were performed at room temperature for pressures up to 10 GPa. The pressure dependence of the vibrational modes suggest the occurrence of orientational ordering transitions induced at 0.5 GPa and 0.8 GPa in C60–C8H8 and C70–C8H8, respectively. In addition, a second anomaly was observed at around 1.3 GPa for C60–C8H8, which could be attributed to the transition to a second, orientationally ordered phase. According to the infrared response, the cubane molecules in C70–C8H8 are more sensitive to the application of pressure compared to C60–C8H8, suggesting larger intermolecular interactions in C70–C8H8. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tube encapsulation effects in various carbon nanotube systems
Authors: Christofilos D. , Arvanitidis J. , Efthimiopoulos E. , Zhao X. , Ando Y. , Takenobu T. , Iwasa Y. , Kataura H. , Ves S. , Kourouklis G. A.
Published: September 2007

In this work, we compare the pressure response of single‐ (SWCNTs), double‐ (DWCNTs) and multi‐wall carbon nanotubes (MWCNTs), as reflected in the normalized pressure derivatives (Γ ‐parameters) of their radial breathing modes (RBMs), probed by Raman spectroscopy. The qualitative characteristics of the experimentally obtained Γ values are well reproduced by a simple anharmonic model. In a nanotube system, the diameters and the number of the constituent coaxial tubes as well as their mutual interaction – strongly depending on their spacing – define its pressure response. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic transport in ambipolar silicon nanowires
Authors: Colli A. , Pisana S. , Fasoli A. , Robertson J. , Ferrari A. C.
Published: September 2007

We investigate and compare the electronic transport in ambipolar SiNWs as a function of the metal choosen for contact deposition. The wires are grown by Au‐catalyzed vapour‐transport and exhibit crystalline cores about 15–20 nm in thickness. The suitability of Ti and Ni contacts on SiNWs is evaluated in terms of contact resistance and band‐alignment. The beneficial effect of a rapid‐thermal‐annealing at mild temperatures (400 °C) is also investigated. We observe that annealed Ni contacts yield the lowest device resistance and highest ON/OFF ratio. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sonication of porphyrin–nanotube composites: a cautionary tale
Authors: Ní Mhuircheartaigh E. M. , Blau W. J. , Prato M. , Giordani S.
Published: September 2007

We report the spectroscopic changes of tetraphenylporphyrin carbon nanotube composites in a variety of chlorinated solvents such as chloroform, dichloroethane and dichlorobenzene as a result of sonication. Detailed data analysis suggests that protonation of the porphyrin core nitrogen atoms occurs as a result of sonodegradation of the solvent molecules. Extreme care must be taken when working with carbon nanotube composite solutions in chlorinated solvents, as sonication is always employed to disperse the nanotubes. This finding is of enormous relevance to the materials chemistry community since these solvents are widely used in preparation of carbon nanotube composite solutions. When working with molecules that are capable of acting as a base some amount of protonation is inevitable and this may dramatically change the physicochemical properties of the composite materials. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Standing‐wave observations in single‐wall carbon nanotube quantum dots and Y‐junction rings
Authors: Grimm Daniel , Latgé Andrea , Venezuela Pedro
Published: September 2007

Standing electronic wave formation inside single walled carbon nanotube Y‐junction rings and quantum dots with a quantum‐dot‐like quadratic dispersion is reported. Remarkably, the detailed structural defect configurations play only a minor role and the standing wave oscillation dispersions are mainly triggered by the electronic properties of the pristine constituent tubes. This raises the possibility of using both structures as nanoscale tuneable electronic switching devices. Near the Fermi level, quantum dots show smooth dispersing oscillations reminiscent of the finite pristine tube eigenvalues. However, localized density of states peaks are found in YJRs, which are identified as interference effects of the double‐slit interferometer. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of 1‐D nanoSiC‐derived nanoporous carbon
Authors: Huczko A. , Osica M. , Bystrzejewski M. , Lange H. , Cudziło S. , Leis J. , Arulepp M.
Published: September 2007

The basic interest of this study was to see whether and how the sorption and electrical double layer (EDL) properties of porous whiskers‐like carbide‐derived carbon (CDC) from SiC nanofibres differ from the commercial SiC‐derived carbon. SiC nanofibres were obtained via combustion synthesis route from CaSi2/PTFE mixture. Resulting carbon material was analysed by powder XRD and low‐temperature nitrogen sorption methods. EDL characteristics were evaluated and compared with CDC obtained from α‐SiC and β‐SiC powders. The cyclic voltammograms and the electrochemical impedance spectroscopy show that the electrical double layer performance of SiC nanofibres‐derived amorphous carbon is better than most of the common pyrolytically made carbons. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Catalytic chemical vapour deposition growth of single wall carbon nanotube films on different substrates for transparent electronic devices
Authors: Ansaldo A. , Skakalova V. , Di Zitti E. , Ricci D. , Roth S.
Published: September 2007

In this work we present our results concerning the growth of transparent carbon nanotube networks. The networks have been successfully grown on both oxidized silicon and quartz‐glass substrates. Conductive and optical properties of these transparent films are discussed and compared to those obtained with other approaches. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vector quantization of mel‐cepstral coefficients using distortion measure for spectral analysis
Authors: Takahashi Toru , Tokuda Keiichi , Kobayashi Takao , Kitamura Tadashi
Published: September 2007

This paper proposes a method for vector quantization of mel‐cepstral coefficients based on a measure for spectral analysis. It is a method in which the match between the input signal within the frame and the mel‐cepstral coefficients stored in the codebook is evaluated by using a statistical measure for spectral analysis, and the quantized mel‐cepstral coefficients are derived. The codebook training algorithm for the proposed method is also presented. The proposed method is further applied to multistage vector quantization. It is shown by an experiment using a speech database that the proposed method with a codebook size of 9 bits can achieve the same quantization distortion as the conventional 12‐bit method (vector quantization based on Euclidean distance between mel‐cepstral coefficients). © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(13): 104–114, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10432
Simultaneous optimization of class configuration and feature space for object recognition
Authors: Shimano Mihoko , Nagao Kenji
Published: September 2007

A new algorithm for object classification based on an extension of Fisher's discriminant analysis is presented. Object recognition algorithms using the standard Fisher's algorithm, such as the Fisherface, train the classifier using sample‐class pairs, where, for the classes, object categories determined in the application systems are used directly. In contrast, the new algorithm automatically produces subclasses, within each predetermined category, that are actually used for classification, via unsupervised learning. In order to perform this, we combine Fisher's discriminant analysis with the Akaike Information Criterion, optimizing the class configuration, that is, sample‐subclass correspondences, and the feature extraction function simultaneously, thereby improving the potential of class separability. By applying this new method to face recognition, we show how it outperforms the traditional Fisher‐based method. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(13): 72–81, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20378