bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Raman spectroscopic characterisation of hydrotalcite with CO32− and VO3− anions in the interlayer
Authors: Palmer Sara J. , Nguyen Tai , Frost Ray L. 
Published: September 2007

AbstractInfrared and Raman spectroscopy were used to characterise synthetic mixed carbonate and vanadate hydrotalcites of formula Mg6Al2(OH)16(CO3)2−, (VO4)3−·4H2 O. The spectra were used to assess the molecular assembly of the cations and anions in the hydrotalcite structure. The spectra may be conveniently subdivided into spectral features based on (1) the carbonate anion (2) the hydroxyl units and (3) water units. Bands were assigned to the hydroxyl stretching vibrations of water. Three types of carbonate anions were identified: (1) carbonate hydrogen‐bonded to water in the interlayer, (2) carbonate hydrogen‐bonded to the hydrotalcite hydroxyl surface and (3) free carbonate anions. It is proposed that the water is highly structured in the hydrotalcite, as it is hydrogen‐bonded to both the carbonate and the hydroxyl surface. The spectra were used to assess the contamination of carbonate in an open reacting vessel in the synthesis of vanadate hydrotalcites of formula Mg6Al2(OH)16(CO3)2−, (VO4)3−·4H2 O. Bands have been assigned to vanadate anions in the infrared and Raman spectra associated with VO bonds. Copyright © 2007 John Wiley & Sons, Ltd.
Raman spectroscopic studies of ZnSe/GaAs interfaces
Authors: El‐Brolossy T. A. , Talaat H. 
Published: September 2007

AbstractZnSe/semi‐insulating GaAs interfaces were studied by observing photogenerated plasmon–LO (PPL) coupled modes by nonresonant micro‐Raman spectroscopy. The effect of the carriers generated by the focused laser beam was investigated for a series of different thicknesses of ZnSe epitaxial layers. The PPL mode in GaAs was observed in the micro‐Raman spectra for all samples, but with different magnitude. The plasma is believed to be an electron gas as a result of the negative nature of the interfacial region that contains predominantly hole traps. The free carrier concentration is estimated to be > 1018 cm−3 and their lifetime ∼0.1 ns. This relatively long lifetime suggests that the ZnSe/GaAs interface has to be of high structural quality leading to a low recombination velocity. ZnSe/GaAs heterostructures of less crystalline quality (as determined by resonant Raman measurements) shows the effect of photogenerated carriers only to lesser extent. Copyright © 2007 John Wiley & Sons, Ltd.
Raman spectroscopic study of the multi‐anion uranyl mineral schroeckingerite
Authors: Frost Ray L. , Čejka Jiří , Ayoko Godwin A. , Dickfos Marilla J. 
Published: September 2007

AbstractRaman spectroscopy complemented with infrared (IR) spectroscopy has been used to study the mineral schroeckingerite. The mineral is a multi‐anion mineral and has (UO2)2+, (SO4)2− and (CO3)2− units in its structure, and bands attributed to these vibrating units are readily identified in the Raman spectra. Symmetric stretching modes at 815, 983 and 1092 cm−1 are assigned to (UO2)2+, (SO4)2− and (CO3)2− units, respectively. The antisymmetric stretching modes of (UO2)2+, (SO4)2− are not observed in the Raman spectra but may be readily observed in the IR spectrum at 898 and 1180 cm−1. The antisymmetric stretching mode of (CO3)2− is observed in the Raman spectrum at 1374 cm−1, as is also the ν4 (CO3)2− bending modes at 742 and 707 cm−1. No ν2 (CO3)2− bending modes are observed in the Raman spectrum of schroeckingerite. All the spectroscopic evidence points to a highly ordered structure of this mineral. Copyright © 2007 John Wiley & Sons, Ltd.
Application of monolithic supports to online extraction and LC‐MS analysis of benzodiazepines in whole blood samples
Authors: Bugey Aurélie , Staub Christian 
Published: September 2007

AbstractA column‐switching (CS) LC‐MS method allowing high‐speed determination of benzodiazepines (BZDs) in whole blood is presented. After protein precipitation with ACN followed by evaporation and reconstitution with the loading mobile phase, the online sample clean‐up was carried out using a CS device. Two extractive precolumns were evaluated: a conventional restricted access material (RAM) sorbent and a monolithic silica support. Separation was achieved using a ChromolithTM Performance RP‐18e (100 mm×4.6 mm id) monolithic silica column, and detection was performed by atmospheric pressure chemical ionization (APCI) MS. The method with both supports has been fully validated according to an accuracy profile approach. Finally, the monolithic silica column, demonstrating better validation data and a higher robustness than the RAM sorbent, was used for the analysis of several real forensic cases.
Numerical evaluation of pressure from experimentally measured film thickness in EHL point contact
Authors: Vaverka Michal , Vrbka Martin , Poliščuk Radek , Křupka Ivan , Hartl Martin 
Published: September 2007

AbstractThis paper is concerned with elastohydrodynamic lubrication, especially the determination of lubricant film thickness and contact pressure within a point contact of friction surfaces of machine parts. A new solution technique for numerical determination of contact pressure is introduced. The direct measurement of contact pressure is very difficult. Hence, input data of lubricant film thickness obtained from the experiment based on colorimetric interferometry are used for the calculation of pressure using the inverse elasticity theory. The algorithm is enhanced by convolution in order to increase calculation speed. The approach described in this contribution gives reliable results on smooth contact and in the future, it will be extended to enable the study of contact of friction surfaces with asperities. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of Polar and Non‐Polar Nano‐Corundum and Uses for Aluminium Carboxylate Hybrid Nanocomposites with Enhanced Surface Mechanical and Viscoelastic Properties
Authors: Gläsel Hans‐Jürgen , Hartmann Eberhard , Mehnert Reiner , Wennrich Luise , Prager‐Duschke Andrea , Khalil Hazem , Hallmeier Karl Heinz , Makhova Ludmila , Thieroff Christoph , Buchmeiser Michael R. 
Published: September 2007

AbstractAmorphous aluminium carboxylate nanoparticles were checked for their potential as precursors for nano‐corundum powders prepared by a high‐temperature conversion process. Exemplifying x‐ray photoelectron spectroscopy studies of the aluminium carboxylate nanoparticles with polar and non‐polar ligands showed that, during the course of the high‐temperature treatment, specific features of the ultrafine organo‐aluminium powders such as polarity/non‐polarity and concomitant hydrophilic/hydrophobic properties were preserved. The resulting nano‐corundum powders were in turn identified as positive synergists for the enforcement of radiation‐cured aluminium carboxylate/acrylate coatings. The simultaneous (optional) use of micro‐corundum particles yielded polymer hybrid coatings. In comparison to acrylate‐based organo‐aluminium nanocomposites, polymeric hybrid coatings revealed significantly improved surface mechanical and viscoelastic properties. In addition to acrylate coatings, other polar and even non‐polar bulk polymers were subject to nano/micro modification using polar and non‐polar nano‐corundum powders, respectively.magnified image
Molecularly Imprinted Nanofiber Membranes from Carboxylated Polysulfone by Electrospray Deposition
Authors: Yoshikawa Masakazu , Nakai Koji , Matsumoto Hidetoshi , Tanioka Akihiko , Guiver Michael D. , Robertson Gilles P. 
Published: September 2007

AbstractIt is demonstrated that polymeric materials can be directly converted into molecular (chiral) recognition nanofiber membranes by simultaneously applying an electrospray deposition and an alternative molecular imprinting during the membrane preparation process. Polysulfone with a degree of substitution of 0.88 was adopted as the candidate polymeric material for molecularly imprinted nanofiber membranes. Molecularly imprinted nanofiber membranes imprinted by Z‐D‐Glu recognize the D‐isomer in preference to the corresponding L‐isomer and vice versa. The amino acid preferentially incorporated into the membrane is selectively permeated through the membrane by using a concentration gradient as a driving force for membrane transport.magnified image
One‐Pot Synthesis of Well‐Defined Amphiphilic and Adaptative Block Copolymers via Versatile Combination of “Click” Chemistry and ATRP
Authors: Mespouille Laetitia , Vachaudez Magali , Suriano Fabian , Gerbaux Pascal , Coulembier Olivier , Degée Philippe , Flammang Robert , Dubois Philippe 
Published: September 2007

AbstractWell‐defined amphiphilic PCL‐b‐PDMAEMA block copolymers were successfully synthesized by a combination of ATRP and “click” chemistry following either a commutative two‐step procedure or a straightforward one‐pot process using CuBr · 3Bpy as the sole catalyst. Compared to the traditional coupling method, combining ATRP and click chemistry even in a “one‐pot” process allows the preparation of PCL‐b‐PDMAEMA diblock copolymers characterized by a narrow molecular weight distribution and quantitative conversion of azides and alkynes into triazole functions. Moreover, the amphiphilic character of these copolymers was demonstrated by surface tension measurements and critical micellization concentration was calculated.magnified image
A New Poly(2,7‐Dibenzosilole) Derivative in Polymer Solar Cells
Authors: Boudreault Pierre‐Luc T. , Michaud Alexandre , Leclerc Mario 
Published: September 2007

AbstractA new soluble conjugated copolymer based on 2,7‐dibenzosilole and 4,7‐dithien‐2‐yl‐2,1,3‐benzothiadiazole units has been synthesized (PBSDTBT). Bulk heterojunction solar cell devices are fabricated using this material as the donor and [6,6]‐phenyl‐C61 butyric acid methyl ester (PCBM) as the acceptor. The power conversion efficiency is 1.6% under AM1.5 illumination. This material also shows a good VOC (0.97 V). The results are quite promising considering the relatively large bandgap (1.9 eV) of this polymer.magnified image
Thermal Degradation Kinetics of Nylon 66: Experimental Study and Comparison with Model Predictions
Authors: Schaffer Mark A. , McAuley Kim B. , Marchildon E. Keith , Cunningham Michael F. 
Published: September 2007

AbstractAn experimental investigation of nonoxidative thermal degradation kinetics of nylon 66 melt under high temperature (280–300 °C) and low water content (0.02–0.14 wt.‐%) conditions is presented. Experimental data for the time evolution of polymer end‐group concentrations and degradation‐product generation rates were compared with the predictions of the only published kinetic model. The omitted influence of water content is a plausible partial explanation for the considerable discrepancy between model predictions and some data. Several previously unreported or unquantified degradation products were identified and measured. Potential additional reactions to account for these results in future kinetic models are proposed.magnified image
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

AbstractBackground: 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

AbstractFinite 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

AbstractWe 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

AbstractIn 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

AbstractDisruptions 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

AbstractThe 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

AbstractThis 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

AbstractPolybutylene 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