bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and characterisation of biodegradable starch‐based nanocomposite materials
Authors: McGlashan Stewart A , Halley Peter J 
Published: October 2003

AbstractDifferent formulations of biodegradable starch–polyester blend nanocomposite materials have been film blown on a pilot scale film blowing tower. The physical properties of different films have been examined by thermal and mechanical analysis and X‐ray diffraction. The results show that the addition of an organoclay (from 0 to 5 wt%) significantly improves both the processing and tensile properties over the original starch blends. Wide angle X‐ray diffraction (WAXD) results indicate that the best results were obtained for 30 wt% starch blends, and the level of delamination depends on the ratio of starch to polyester and amount of organoclay added. The crystallisation temperature of the nanocomposite blends is significantly lower than the base blend. This is probably due to the platelets inhibiting order, and hence crystallisation, of the starch and polyester. The mechanical and thermal properties of the blends are also sensitive to the way the clay particles are dispersed. Copyright © 2003 Society of Chemical Industry
Polyethylene‐layered silicate nanocomposites for rotational moulding
Authors: Martin Darren , Halley Peter , Truss Rowan , Murphy Michael , Jackson Oliver , Kwon Oh‐Yun 
Published: October 2003

AbstractA series of polyethylene‐layered silicate nanocomposites has been studied as possible new candidates for rotational moulding. Two organically treated layered silicates were melt‐compounded into a maleated linear low‐density polyethylene host polymer at loadings of 6 and 9%, by weight. The morphology and properties of the nanocomposites were assessed by using dynamic mechanical thermal analysis, parallel‐plate rheometry, wide‐angle X‐ray diffraction and transmission electron microscopy. The sintering behaviour of the nanocomposites was qualitatively assessed via hot‐stage microscopy, indicating that the choice of nanofiller will play an important role in terms of producing nanocomposite materials with acceptable processability for rotational moulding. Copyright © 2003 Society of Chemical Industry
NMR characterization of blends of poly(hydroxybutyrate–co‐hydroxyvalerate) with poly(vinyl acetate)
Authors: Hill David JT , Markotsis Martin , Whittaker Andrew K , Wong Kathy W 
Published: October 2003

AbstractThe extent of mixing in blends of poly(hydroxybutyrate‐co‐hydroxyvalerate) (PHBV) (27% HV) and poly(vinyl acetate) (PVAc) has been measured using a number of different techniques, principally solid‐state NMR. Differential scanning calorimetry DSC measurements indicated effective mixing of the polymer chains on a scale of several nanometres. The results of 1H T1 and 1H T1ρ measurements confirm intimate mixing of the chains. A change on blending in the 1H T1ρ, and the 1H NMR line width of the signal from the protons of PVAc was consistent with an increase in the amplitude and frequency of motion of this component. The PVAc chains reside within the inter‐lamellar space, as confirmed by spin diffusion measurements after 1H T1ρ preparation. Copyright © 2003 Society of Chemical Industry
Early propagation kinetics in the free radical polymerization of methacrylonitrile investigated by a nitroxide trapping technique
Authors: Ewing Katrina , Busfield W Ken , Jenkins Ian D , Zetterlund Per B 
Published: October 2003

AbstractThe first seven addition products in the free radical polymerization of methacrylonitrile initiated by AIBN have been trapped by using a nitroxide trapping technique. In this experiment, the concentration of trap is maintained at a level sufficiently high to prevent the formation of high polymer, yet low enough to allow competitive monomer addition to form the lower members of the propagation series before being trapped to form the oligomeric addition products. These oligomers have been identified and quantified by electrospray ionization‐mass spectrometry (ESI‐MS) in series with HPLC–UV. The results have allowed individual propagation rate coefficients in the early stages of polymerization to be estimated. The variation in kpn for n = 1 and n = 3–7, where n is the number of monomer units in the propagating radical, is less than the experimental precision, with an average value at 75°C of 1.9 ± 1.0 × 104 l mol−1 s−1. As with other monomers, however, kpn for the first few propagation steps is significantly greater than the value for high polymer measured by the pulsed laser polymerization technique. Copyright © 2003 Society of Chemical Industry
N‐substituent effect of maleimides on acrylate polymerization initiated by three‐component systems
Authors: Clark SC , Hill DJT , Hoyle CE , Jönsson S , Miller CW , Shao LY 
Published: October 2003

AbstractIn this paper, the relative photopolymerization efficiency for polymerization of a difunctional acrylate initiated by various N‐substituted maleimides in the presence of amine and benzophenone are compared on the basis of a photo‐differential scanning calorimetry (photo‐DSC) study. The trends in the polymerization rates were obtained from the photopolymerization profiles and expressed in terms of a photoinitiation index, Ip. An N‐substituent index, Is, which indicates whether each N‐substituent plays either a positive (when Is > 1) or a negative (when Is < 1) role in the initiation process relative to MI (unsubstituted maleimide), was determined. Copyright © 2003 Society of Chemical Industry
Radical formation on γ‐radiolysis of poly [(methacrylic acid)‐co‐acrylonitrile]
Authors: Fox Peter A , Hill David JT , Lang Anthony P , Pomery Peter J 
Published: October 2003

AbstractThe radicals formed on γ‐radiolysis of a series of copolymers of methacrylic acid and acrylonitrile have been investigated by ESR spectroscopy. This series of copolymers spanned the full composition range and the study was carried out at 77 K and ambient temperature. The radicals formed in the copolymers at 77 and 303 K were found to be similar to those found in the two homopolymers, but in the intermediate composition range the presence of acrylonitrile propagation radicals was also detected. These radicals were not observed to be formed in significant quantities on the radiolysis of polyacrylonitrile. They are believed to result from a scission of the main chain at methacrylic acid/acrylonitrile diad sequences following loss of the methacrylic acid carboxyl group. At 77 K, the copolymers with high methacrylic acid contents were found to be more sensitive to radical formation than the methacrylic acid homopolymer, but this enhanced sensitivity was not evident at ambient temperature, where the G‐values for radical formation for the copolymers were slightly less than the values for the homopolymers. Copyright © 2003 Society of Chemical Industry
Chain scission and branching in irradiated poly(tetrafluoroethylene‐co‐hexafluoropropylene)
Authors: Hill DJT , Mohajerani S , Whittaker AK , Scheler U 
Published: October 2003

AbstractThe radiation chemistry of poly(tetrafluoroethylene‐co‐hexafluoropropylene) (FEP) with a TFE mole fraction of 0.90 has been studied under vacuum using 60Co γ‐radiation over a range of temperatures and absorbed doses. The radiolysis temperatures were 300, 363, 423, 523 and 543 K. New structure formation in the copolymers was analysed by solid‐state 19F NMR spectroscopy. The new structures formed in the copolymers have been identified and the G‐values for the formation of new chemical structures have been investigated at 363 and 523 K. These two temperatures are just above and just below the polymer Tg and Tm, respectively. At the lower temperature, there was no evidence for any chain branching and an estimate of G(S) of 1.0 was obtained. A value of G(S) of 1.3 and a minimum value of G(X)Y of 1.3 were obtained at 523 K. Copyright © 2003 Society of Chemical Industry
Profiling and imaging proteins in the mouse epididymis by imaging mass spectrometry
Authors: Chaurand Pierre , Fouchécourt Sophie , DaGue Beverly B. , Xu Baogang J. , Reyzer Michelle L. , Orgebin‐Crist Marie‐Claire , Caprioli Richard M. 
Published: October 2003

AbstractDifferent aspects of matrix‐assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) have been used as discovery tools to obtain global and time‐correlated information on the local proteomic composition of the sexually mature mouse epididymis from both qualitative and semiquantitative points of view. Tissue sections and laser captured microdissected cells and secretory products were analyzed by MALDI‐MS and from the recovered protein profiles, over 400 different proteins were monitored. Over 50 of these, some of which have been identified, displayed regionalized behavior from caput to cauda within the epididymis. Combining the information obtained from high‐resolution imaging mass spectrometry and laser captured microdissection experiments, numerous proteins were localized within the epididymis at the cellular level. Furthermore, from the signal intensities observed in the different protein profiles organized in space, semiquantitative information for each protein was obtained.
Protein arrays for autoantibody profiling and fine‐specificity mapping
Authors: Robinson William H. , Steinman Lawrence , Utz Paul J. 
Published: October 2003

AbstractProtein arrays provide a powerful approach to study autoimmune disease. Autoimmune responses activate B cells to produce autoantibodies that recognize self‐molecules termed autoantigens, many of which are proteins or protein complexes. Protein arrays enable profiling of the specificity of autoantibody responses against panels of peptides and proteins representing known autoantigens as well as candidate autoantigens. In addition to identifying autoantigens and mapping immunodominant epitopes, proteomic analysis of autoantibody responses will further enable diagnosis, prognosis, and tailoring of antigen‐specific tolerizing therapy.
Protein microarrays: Molecular profiling technologies for clinical specimens
Authors: Espina Virginia , Mehta Arpita I. , Winters Mary E. , Calvert Valerie , Wulfkuhle Julia , Petricoin Emanuel F. , Liotta Lance A. 
Published: October 2003

AbstractProteomics, the study of protein function within biologic systems, will further our understanding of cancer pathogenesis. Coupled with transcript profiling, proteomics can herald the advent of molecular therapy tailored to the individual patient's neoplasm. Protein microarrays, one emerging class of proteomic technologies, have broad applications for discovery and quantitative analysis. This technology is uniquely suited to gather information about the post‐translational modifications of proteins reflecting the activity state of signal pathways and networks. Protein microarrays now make it feasible to conduct signal network profiling within cellular samples. Nevertheless, to be successful, design and use of protein microarrays must take into consideration enormous analytical challenges. A subclass of protein microarrays, Reverse Phase Arrays, created to meet these challenges, has been optimized for use with tissue specimens, and is now in use for the analysis of biopsy samples for clinical trial research.
Signal pathway profiling of prostate cancer using reverse phase protein arrays
Authors: Grubb Robert L. , Calvert Valerie S. , Wulkuhle Julia D. , Paweletz Cloud P. , Linehan W. Marston , Phillips John L. , Chuaqui Rodrigo , Valasco Alfredo , Gillespie John , Emmert‐Buck Michael , Liotta Lance A. , Petricoin Emanuel F. 
Published: October 2003

AbstractReverse phase protein arrays represent a new proteomics microarray technology with which to study the fluctuating state of the proteome in minute quantities of cells. The activation status of cell signaling pathways controls cellular fate and deregulation of these pathways underpins carcinogenesis. Changes in pathway activation that occur between early stage prostatic epithelial lesions, prostatic stroma and the extracellular matrix can be analyzed by obtaining pure populations of cell types by laser capture microdissection (LCM) and analyzing the relative states of several key phosphorylation points within the cellular circuitry. We have applied reverse phase protein array technology to analyze the status of key points in cell signaling involved in pro‐survival, mitogenic, apoptotic and growth regulation pathways in the progression from normal prostate epithelium to invasive prostate cancer. Using multiplexed reverse phase protein arrays coupled with LCM, the states of signaling changes during disease progression from prostate cancer study sets were analyzed. Focused analysis of phospho‐specific endpoints revealed changes in cellular signaling events through disease progression and between patients. We have used a new protein array technology to study specific molecular pathways believed to be important in cell survival and progression from normal epithelium to invasive carcinoma directly from human tissue specimens. With the advent of molecular targeted therapeutics, the identification, characterization and monitoring of the signaling events within actual human biopsies will be critical for patient‐tailored therapy.
Identification of repertoires of surface antigens on leukemias using an antibody microarray
Authors: Belov Larissa , Huang Pauline , Barber Nicole , Mulligan Stephen P. , Christopherson Richard I. 
Published: October 2003

AbstractWe have previously described a microarray of cluster of differentiation (CD) antibodies that enables concurrent determination of more than 60 CD antigens on leukocytes. This procedure does not require protein purification or labeling, or a secondary detection system. Whole cells are captured by a microarray of 10 nL antibody dots immobilized on a nitrocellulose film on a microscope slide. Distinct patterns of cell binding are observed for different leukemias or lymphomas. These haematological malignancies arise from precursor cells of T‐ or B‐lymphocytic, or myeloid lineages of hematopoiesis. The dot patterns obtained from patients are distinct from those of peripheral blood leukocytes from normal subjects. This microarray technology has recently undergone a number of refinements. The microarray now contains more CD antibodies, and a scanner for imaging dot patterns and software for data analysis provide an extensive immunophenotype sufficient for diagnosis of common leukemias. The technology is being evaluated for diagnosis of leukemias with parallel use of conventional diagnostic criteria.
Protein microarrays: Promising tools for proteomic research
Authors: Templin Markus F. , Stoll Dieter , Schwenk Jochen M. , Pötz Oliver , Kramer Stefan , Joos Thomas O. 
Published: October 2003

AbstractMiniaturized and parallelized ligand binding assays are of great interest in postgenomic research because microarray technology allows the simultaneous determination of a large number of parameters from a minute amount of sample within a single experiment. Assay systems based on this technology are used for the identification and quantification of proteins as well as for the study of protein interactions. Protein affinity assays have been implemented that allow the analysis of interactions between proteins with other proteins, peptides, low molecular weight compounds, oligosaccharides or DNA. Microarray technology is an emerging technology used in global analytical approaches and has a considerable impact on proteomic research.
Carbohydrate microarrays
Authors: Wang Denong 
Published: October 2003

AbstractSugar chains are abundantly expressed on the outer surfaces of the vast majority of viral, bacterial, protozoan and fungal pathogens, as well as on the membranes of mammalian cells. This class of carbohydrate molecule is without peer in structural diversity and is characteristically suitable for storing and displaying biological signals for molecular and cellular recognition. Exploring the biological information contained in sugar chains is an important topic of current postgenomic research. To facilitate these investigations, we have focused on the establishment of a carbohydrate‐based microarray technology. Recently, we reported that a large panel of carbohydrate‐containing macromolecules, including polysaccharides, natural glycoconjugates, and the mono‐ and oligosaccharides coupled to carrier molecules, can be stably immobilized on a microglass slide to produce a large‐scale carbohydrate microarray. In this review, we attempt to summarize our recent progress in using this technology to uncover the carbohydrate‐based biological signals that are recognized by the human and animal immune systems. We also discuss the potential of various platforms of carbohydrate microarrays that were recently established and analyze the challenges to future development of carbohydrate microarray technologies and their applications.
Current status of protein chip development in terms of fabrication and application
Authors: Seong Seung‐yong , Choi Cheol‐young 
Published: October 2003

AbstractSequencing of the human genome revealed that more than 30 000 genes encode proteins comprising the human proteome. “Proteomics” can be defined as a field of research studying proteins in terms of their function, expression, structure, modification and their interaction in physiological and in pathological states. The concentration, modification and interaction of proteins in cells, plasma, and in tissues are crucial in determining the phenotype of living organisms. Although fluctuation of protein concentration is essential to maintain homeostasis, protein expression levels are also pathognomonic features. Estimating protein concentration by analyzing the quantity of mRNA in cells through conventional technologies, such as DNA chips, does not provide precise values since the half‐life and translation efficacy of mRNA is variable. In addition, polypeptides undergo post‐translational modification. For these reasons, novel techniques are needed to analyze multiple proteins simultaneously using protein microarrays. In the near future, protein chips may allow construction of complete relational databases for metabolic and signal transduction pathways. This article reviews the current status of technologies for fabricating protein microarrays and their applications.
Microarrays of tumor cell derived proteins uncover a distinct pattern of prostate cancer serum immunoreactivity
Authors: Bouwman Kerri , Qiu Ji , Zhou Heping , Schotanus Mark , Mangold Leslie A. , Vogt Robert , Erlandson Erik , Trenkle John , Partin Alan W. , Misek David , Omenn Gilbert S. , Haab Brian B. , Hanash Samir 
Published: October 2003

AbstractThe broad characterization of the immune responses elicited by tumors has valuable applications in diagnostics and basic research. We present here the use of microarrays of tumor‐derived proteins to profile the antibody repertoire in the sera of prostate cancer patients and controls. Two‐dimensional liquid chromatography was used to separate proteins from the prostate cancer cell line LNCaP into 1760 fractions. These fractions were spotted in microarrays on coated microscope slides, and the microarrays were incubated individually with serum samples from 25 men with prostate cancer and 25 male controls. The amount of immunoglobulin bound to each fraction by each serum sample was quantified. Statistical analysis revealed that 38 of the fractions had significantly higher levels of immunoglobulin binding in the prostate cancer samples compared to the controls. Two fractions showed higher binding in the control samples. The significantly higher immunoglobulin reactivity from the prostate cancer samples may reflect a strong immune response to the tumors in the prostate cancer patients. We used multivariate analysis to classify the samples as either prostate cancer or control. In a cross‐validation study, recursive partitioning classified the samples with 84% accuracy. A decision tree with two levels of partitioning classified the samples with 98% accuracy. Additional studies will allow further characterization of tumor antigens in prostate cancer and their significance for diagnosis. These results suggest that microarrays of fractionated proteins could be a powerful tool for tumor antigen discovery and cancer diagnosis.
CH and NH bond dissociation energies of five‐ and six‐membered ring aromatic compounds
Authors: Feng Yong , Wang Jin‐Ti , Liu Lei , Guo Qing‐Xiang 
Published: October 2003

AbstractCH and NH bond dissociation energies (BDEs) of various five‐ and six‐membered ring aromatic compounds were calculated using composite ab initio CBS‐Q, G3 and G3B3 methods. It was found that all these composite ab initio methods provided very similar BDEs, despite the fact that different geometries and different procedures in the extrapolation to complete incorporation of electron correlation and complete basis set limit were used. Therefore, the calculated BDEs should be reliable. In addition, we found interesting dependences of the CH BDEs on the bond angles, spins and charges. A good quantitative structure–activity relationship (QSAR) model for the CH BDEs of aromatic compounds was also established. Copyright © 2003 John Wiley & Sons, Ltd.
New permanently charged phenanthridinium–nucleobase conjugates. Interactions with nucleotides and polynucleotides and recognition of ds‐polyAH+
Authors: Tumir Lidija‐Marija , Piantanida Ivo , Cindrić Iva Juranović , Hrenar Tomica , Meić Zlatko , Žinić Mladen 
Published: October 2003

AbstractN‐Methyl‐8‐aminophenathridinium–uracil and –adenine conjugates possessing a nucleobase attached at the phenanthridinium 8‐amino group by a trimethylene spacer were prepared in the form of water‐soluble hydrogensulfate salts. Spectroscopic characteristics of the conjugates reveal the formation of folded conformations in water characterized by intramolecular aromatic stacking between the phenanthridinium unit and the tethered nucleobase. The conjugates form 1:1 complexes in water with either complementary or non‐complementary nucleotides, giving log Ks values between 1 and 2 and showing a lack of any base recognition. Also, the binding studies with single‐stranded polynucleotides showed no preference of conjugates to polynucleotides containing complementary nucleobases. At pH 5, the N‐methylphenanthridinium–adenine conjugate exhibited preferred binding to double‐stranded (ds‐) polyAH+, whereas its protonated analogue bound preferably to polyU. The results reveal that the presence of protonated or permanently charged intercalator units in the conjugates dramatically changes their binding preferences for polynucleotides. Copyright © 2003 John Wiley & Sons, Ltd.
Evidence for extended π,n‐participation in solvolysis of some benzyl chlorides
Authors: Jurić Sandra , Filipović Anita , Kronja Olga 
Published: October 2003

AbstractChlorides 3 (1‐aryl‐1‐chloro‐4‐methyl‐7‐methoxy‐4‐heptene) and 4 (1‐aryl‐1‐chloro‐4‐methyl‐4‐hexene) with various phenyl substituents were prepared (Y=p‐OCH3, p‐CH3, H and m‐Br) and the solvolysis rates were measured in 80% (v/v) aqueous ethanol. The rate constants of 3 correlate well with σ+, and the ϱ+ value obtained is −1.45±0.15, whereas with 4 breakdown of the Hammett plot occurs, and the ϱ+ value without the p‐anisyl group is −2.55±0.20, indicating extended π,n‐participation in 3 and simple π‐participation in 4. The drastically smaller activation parameters obtained with 3 than with 4 are consistent with the proposed mechanism in which the high degree of order required in the transition state (large negative ΔS‡) is overcompensated by a small ΔH‡. Copyright © 2003 John Wiley & Sons, Ltd.