bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deposition mechanisms in langmuir‐blodgett films
Authors: Peterson I. R. , Russell G. J. 
Published: April 2007

AbstractAs part of a study of the possible application of polymerisable Langmuir‐Blodgett (LB) films as ultra‐fine‐line e‐beam resists, an investigation of the variation of film structure of 22‐tricosenoic acid with differing deposition conditions has been made. Unexpected effects with significant implications for deposition speed and resist sensitivity have been observed, and the new techniques for film characterisation developed during the investigation have resulted in a revised model of deposition explaining the observed independence of the disorder causing optical scattering and the macroscopic features observed by polarised microscopy.
Langmuir‐blodgett films from preformed polymers
Authors: Hodge Philip , Khoshdel Ezzatollah , Tredgold Richard H. , Vickers Anthony J. , Winter Christopher S. 
Published: April 2007

AbstractRecent work on Langmuir films and Langmuir‐Blodgett films prepared from derivatives of styrene‐maleic anhydride and octadec‐1‐ene‐maleic anhydride copolymers is reviewed.
Fundamentals of Hydrogels and Gelation
Authors: Ross‐Murphy Simon B. , McEvoy Henry 
Published: April 2007

AbstractA discussion of the properties of that class of materials known as ‘hydrogels’ must make particular reference to (i) a working definition of what is meant by a ‘gel’, (ii) the manner in which this relates to the underlying macromolecular structure, and (iii) how these properties are affected by the presence of water within the macromolecular network. The first point is answered by providing an operational definition of a gel, which depends on the mechanical response of the material to oscillatory shear. This type of behaviour is shown to be quantitatively related to the degree of connectivity of the network. The chemical aspects of the problem address the relationship between this and the degree of reaction achieved by those chemical or physical features responsible for crosslinking. Finally, the swelling properties of such materials are discussed, and how these are complicated by the non‐ideal thermodynamic properties of the solvent water.
The Role of Permeability and Related Properties in the Design of Synthetic Hydrogels for Biomedical Applications
Authors: Tighe Brian J. 
Published: April 2007

AbstractSynthetic hydrogels are a versatile range of materials which are of value in several biomedical applications, particularly those where permeability is important. Because the equilibrium water content of the gel governs permeability processes and has a marked influence on other important properties, the permeability requirements of a material often influence other aspects of its behaviour. The design of hydrogels for contact lenses demands an understanding of these interrelationships and thus provides a valuable basis for extending hydrogel design to other applications.
Molecular Interactions in Polysaccharide Gelation
Authors: Morris Edwin R. 
Published: April 2007

AbstractThe gel structures formed by naturally occurring polysaccharides, either in vivo (in, for example, plant tissue) or in vitro after extraction and purification, are normally crosslinked by extended intermolecular ‘junction zones’ of conformationally ordered chains. Formation and disruption of these ordered structures under biologically and industrially relevant conditions of extensive hydration may be monitored and characterised by a variety of physical techniques, in conjunction with x‐ray analysis at atomic resolution in the condensed phase by fibre diffraction. Interconnecting regions of residual disorder, necessary for solubilisation of the gel network, may be introduced by structural irregularities or block character in the primary sequence.
Synthetic Hydrogels as Substrata for Cell Adhesion Studies
Authors: Lyndon Michael J. 
Published: April 2007

AbstractSynthetic polymer hydrogels have many proven and potential biomedical applications as wound coverings, drug delivery systems, surgical prostheses, contact lenses and in extracorporeal circuitry. Their success in long‐term contact with biological fluids and cellular tissue depends upon their interfacial properties in such environments, and in turn, upon their physical and chemical nature. One approach to defining requirements for interfacial events at polymer surfaces in vivo is to investigate cell adhesion behaviour on these materials in culture, and to correlate this behaviour with polymer structure and theories of in vivo biocompatibility. At the same time, polymer hydrogels provide the opportunity to extend existing cell culture systems for the study of environmental cues for cell behaviour under normal and pathological circumstances.
The Diffusion of Compact Macromolecules Within Hydrogels
Authors: Sellen D. B. 
Published: April 2007

AbstractStudies of the diffusion of globular proteins and dextran fractions within polysaccharide and poly‐acryamide gels by laser light scattering are described. Gels of stiff polysaccharide chains scatter light which exhibits little spectral broadening, since apart from a small amount of structural relaxation they are almost stationary at a molecular level. Well defined diffusion coefficient of compact macromolecules within these gels can be measured. However, gels of relatively flexible polymers such as polyacrylamide are highly mobile at a molecular level, and scatter light which is spectrally broadened by the diffusion of fluctuations in acrylamide concentration. In this case there is a complex interaction between the two diffusion coefficients, with the diffusing compact macromolecules dominating at low gel concentrations, and the diffusing gel fluctuations dominating at high gel concentrations where they tend to control the movement of the compact macromolecules.
Controlled Release from Crosslinked Poloxamer Hydrogels
Authors: Law T. K. , Whateley T. L. , Florence A. T. 
Published: April 2007

AbstractChemically modified derivatives of the copolymeric poloxamer surfactants have been polymerised to form crosslinked, swelling hydrogels. Mixtures of derivatives of poloxamers 188 and 181 form gels which show increased swelling with increased content of the more hydrophilic poloxamer 188. The rate of release of benzoic and p‐hydroxybenzoic acids also increases with increasing content of poloxamer 188. Release rate data have been analysed in terms of the swelling controlled release model for these hydrogels.
Effect of Processing Conditions on Styrene‐Butadiene‐Styrene‐Thermoplastic Rubber
Authors: Canevarolo Sebastio V. , Birley Arthur W. , Hemsley Derek A. 
Published: April 2007

AbstractThe effects of shear rate, extrusion temperature and heat treatment on a lamellar triblock copolymer of styrene‐butadiene‐styrene were studied using extrudates from a capillary rheometer. The rheological behaviour is mainly non‐Newtonian in the region studied and the flow curves can be time‐temperature reduced. The quality of the domain structure PS phase was measured mechanically in terms of the stress at yield and optically by birefringence. Some of the factors considered during the analysis of the results are: rearrangement of the imperfect original domain structure taking place in the barrel, before extrusion, for temperatures higher than 145°C; partial destruction of this pre‐developed structure during extrusion; orientation of the chains during extrusion and under some conditions, the development of sharkskin on the surface of the extrudate. The heat treatment induces the copolymer to undergo three processes: internal stress relaxation (∼135°C); rearrangement of the imperfect domain structure (145°CT240°C); and crosslinking in the rubbery phase (T200°C).
Proteomic analysis of rice plasma membrane reveals proteins involved in early defense response to bacterial blight
Authors: Chen Fang , Yuan Yuexing , Li Qun , He Zuhua 
Published: April 2007

AbstractPlant plasma membrane (PM) proteins play important roles in signal transduction during defense response to an attacking pathogen. By using an improved method of PM protein preparation and PM‐bound green fluorescent protein fusion protein as a visible marker, we conducted PM proteomic analysis of the rice suspension cells expressing the disease resistance gene Xa21, to identify PM components involved in the early defense response to bacterial blight (Xanthomonas oryzae pv. oryzae). A total of 20 regulated protein spots were observed on 2‐D gels of PM fractions at 12 and 24 h after pathogen inoculation, of which some were differentially regulated between the incompatible and compatible interactions mediated by Xa21, with good correlation between biological repeats. Eleven protein spots with predicted functions in plant defense were identified by MS/MS, including nine putative PM‐associated proteins H+‐ATPase, protein phosphatase, hypersensitive‐induced response protein (OsHIR1), prohibitin (OsPHB2), zinc finger and C2 domain protein, universal stress protein (USP), and heat shock protein. OsHIR1 was modified by the microbal challenge, leading to two differentially accumulated protein spots. Transcript analysis showed that most of the genes were also regulated at transcriptional levels. Our study would provide a starting point for functionality of PM proteins in the rice defense.
Proteomic analysis of up‐regulated proteins in human promonocyte cells expressing severe acute respiratory syndrome coronavirus 3C‐like protease
Authors: Lai Chien‐Chen , Jou Ming‐Jia , Huang Shiuan‐Yi , Li Shih‐Wein , Wan Lei , Tsai Fuu‐Jen , Lin Cheng‐Wen 
Published: April 2007

AbstractThe pathogenesis of severe acute respiratory syndrome coronavirus (SARS CoV) is an important issue for treatment and prevention of SARS. Previously, SARS CoV 3C‐like protease (3CLpro) has been demonstrated to induce apoptosis via the activation of caspase‐3 and caspase‐9 (Lin, C. W., Lin, K. H., Hsieh, T. H., Shiu, S. Y. et al., FEMS Immunol. Med. Microbiol. 2006, 46, 375–380). In this study, proteome analysis of the human promonocyte HL‐CZ cells expressing SARS CoV 3CLpro was performed using 2‐DE and nanoscale capillary LC/ESI quadrupole‐TOF MS. Functional classification of identified up‐regulated proteins indicated that protein metabolism and modification, particularly in the ubiquitin proteasome pathway, was the main biological process occurring in SARS CoV 3CLpro‐expressing cells. Thirty‐six percent of identified up‐regulated proteins were located in the mitochondria, including apoptosis‐inducing factor, ATP synthase beta chain and cytochrome c oxidase. Interestingly, heat shock cognate 71‐kDa protein (HSP70), which antagonizes apoptosis‐inducing factor was shown to down‐regulate and had a 5.29‐fold decrease. In addition, confocal image analysis has shown release of mitochondrial apoptogenic apoptosis‐inducing factor and cytochrome c into the cytosol. Our results revealed that SARS CoV 3CLpro could be considered to induce mitochondrial‐mediated apoptosis. The study provides system‐level insights into the interaction of SARS CoV 3CLpro with host cells, which will be helpful in elucidating the molecular basis of SARS CoV pathogenesis.
Differential proteomic analysis of the endoplasmic reticulum from developing and germinating seeds of castor (Ricinus communis) identifies seed protein precursors as significant components of the endoplasmic reticulum
Authors: Maltman Daniel J. , Gadd Stephen M. , Simon William J. , Slabas Antoni R. 
Published: April 2007

AbstractThe endoplasmic reticulum is a major compartment of storage protein and lipid biosynthesis. Maximal synthesis of these storage compounds occurs during seed development with breakdown occurring during germination. In this study, we have isolated four independent preparations of ER from both developing and germinating seeds of castor bean (Ricinus communis) and used 2‐D DIGE, and a combination of PMF and MS/MS sequencing, to quantify and identify differences in protein complement at both stages. Ninety protein spots in the developing seeds are up‐regulated and 19 individual proteins were identified, the majority of these are intermediates of seed storage synthesis and protein folding. The detection of these transitory storage proteins in the ER is discussed in terms of protein trafficking and processing. In germinating seed ER 15 spots are elevated, 5 of which were identified, amongst them was malate synthetase which is a component of the glyoxysome which is believed to originate from the ER. Notably no proteins involved in complex lipid biosynthesis were identified in the urea soluble ER fraction indicating that they are probably all integral membrane proteins.
Down‐regulation of pigment epithelium‐derived factor in uveitic lesion associates with focal vascular endothelial growth factor expression and breakdown of the blood‐retinal barrier
Authors: Deeg Cornelia A. , Altmann Frank , Hauck Stefanie M. , Schoeffmann Stephanie , Amann Barbara , Stangassinger Manfred , Ueffing Marius 
Published: April 2007

AbstractSpontaneous equine recurrent uveitis (ERU) is an incurable autoimmune disease affecting the eye. Identifying biological markers or pathways associated with this disease may allow the understanding of its pathogenesis at a molecular level. The vitreous is the body fluid closest to the disease‐affected tissue and possibly also an effector of pathological processes relevant for ERU. Surgical removal of vitreous leads to cessation of relapses in spontaneous uveitis of both man and horse, therefore vitreous composites are likely to contribute to disease progression. Uveitic vitreous is likely to contain potential biomarkers in relatively undiluted quantities. With the goal to identify these markers, we systematically compared vitreous from healthy and disease‐affected eyes by proteomic profiling. Nine differentially expressed proteins were identified, that are functionally related to immune response, inflammation, and maintenance of the blood‐retinal barrier. One of these, pigment epithelium‐derived factor, a protein involved in maintaining a proper blood‐retina barrier as well as protecting from neoangiogenesis was additionally found to be down‐regulated within uveitic retinal lesions whereas, conversely, vascular endothelial growth factor was found to be up‐regulated at these sites. Together, these changes point to as of yet undiscovered biological pathways involved in the pathogenesis of this autoimmune disease.
A proteomic‐based approach for the characterization of some major structural proteins involved in host–parasite relationships from the silkworm parasite Nosema bombycis (Microsporidia)
Authors: Wang Jian‐Yang , Chambon Christophe , Lu Chang‐De , Huang Ke‐Wei , Vivarès Christian P. , Texier Catherine 
Published: April 2007

AbstractNosema bombycis is the causative agent of the silkworm Bombyx mori pebrine disease which inflicts severe worldwide economical losses in sericulture. Little is known about host–parasite interactions at the molecular level for this spore‐forming obligate intracellular parasite which belongs to the fungi‐related Microsporidia phylum. Major microsporidian structural proteins from the spore wall (SW) and the polar tube (PT) are known to be involved in host invasion. We developed a proteomic‐based approach to identify few N. bombycis proteins belonging to these cell structures. Protein extraction protocols were optimized and four N. bombycis spore protein extracts were compared by SDS‐PAGE and 2‐DE to establish complementary proteomic profiles. Three proteins were shown to be located at the parasite SW. Moreover, 17 polyclonal antibodies were raised against major N. bombycis proteins from all extracts, and three spots were shown to correspond to polar tube proteins (PTPs) by immunofluorescent assay and transmission electron microscopy immunocytochemistry on cryosections. Specific patterns for each PTP were obtained by MALDI‐TOF‐MS and MS/MS. Peptide sequence tags were deduced by de novo sequencing using Peaks Online and DeNovoX, then evaluated by MASCOT and SEQUEST searches. Identification parameters were higher than false‐positive hits, strengthening our strategy that could be enlarged to a nongenomic context.
Enhancement of proteolysis through the silica‐gel‐derived microfluidic reactor
Authors: Liu Yun , Qu Haiyun , Xue Yan , Wu Zhonglin , Yang Pengyuan , Liu Baohong 
Published: April 2007

AbstractAn on‐chip enzymatic reactor providing rapid protein digestion is presented. Trypsin‐embedding stationary phase within the microchannel has been prepared by the sol‐gel method. Such a microfluidic reactor has been used for low‐level protein digestion at 16 fmol per analysis. The analytical potential of the microreactor combined with the strong cation exchange and RPLC ESI‐MS/MS for the identification of real samples from the cytoplasma of the human liver tissue has been demonstrated.
C‐Terminal antibodies (CTAbs): A simple and broadly applicable approach for the rapid generation of protein‐specific antibodies with predefined specificity
Authors: Edwards Robert J. , Wrigley Amanda , Bai Zhonghu , Bateman Michaela , Russell Hugh , Murray Stephen , Lu Huafeng , Taylor Graham W. , Boobis Alan R. , Sriskandan Shiranee 
Published: April 2007

AbstractRecent advances in proteomic techniques have resulted in an ever‐increasing need to produce antibodies. Here, to address this problem, a technically simple approach of targeting the extreme C‐termini of proteins with antibodies (CTAbs) was investigated in proteins secreted by the human pathogen Streptococcus pyogenes. Target proteins were identified by a conventional proteomic approach and CTAbs produced against synthetic five amino acid peptides representing the C‐terminus of each target protein. In every case where protein secretion was demonstrated (n = 20), CTAbs were successfully produced and bound specifically to the target protein (100% success rate). The apparent specificity was consistent with the structural heterogeneity of the C‐termini of S. pyogenes proteins. The global specificity of CTAb binding was defined using a combinatorial library of synthetic peptides representing structural variants of the original synthetic immunogen. This is a systematic and comprehensive approach for the development of antibodies with defined specificity that can be used in a range of applications.
A widespread picture of the Streptococcus thermophilus proteome by cell lysate fractionation and gel‐based/gel‐free approaches
Authors: Salzano Anna Maria , Arena Simona , Renzone Giovanni , D'Ambrosio Chiara , Rullo Rosario , Bruschi Maurizio , Ledda Luigi , Maglione Giuseppe , Candiano Giovanni , Ferrara Lino , Scaloni Andrea 
Published: April 2007

AbstractAmong the group of lactic acid bacteria, Streptococcus thermophilus has found a wide application in industrial processes used for the manufacture of dairy products. Taking advantage of different proteome extraction and subfractionation protocols, bacterial cytosolic and membrane proteins were isolated and resolved by independent gel‐free and gel‐based separation procedures. Whole cytosolic fraction and its acid, basic and low molecular mass protein components were separated by different resolutive 2‐DE and tricine 1‐DE gels and identified by MALDI‐TOF PMF and/or μLC‐ESI‐IT‐MS/MS. Membrane proteins were resolved by 2‐DE and SDS‐PAGE gels and similarly identified by PMF and TMS analysis. In parallel, whole extract was trypsinized and resulting peptides were identified by shotgun 2‐D LC‐ESI‐IT‐MS/MS analysis. Using this combined approach, expression products corresponding to 458 different genes were identified, which cover almost a third of the predicted vegetative proteome. Relative protein concentration and hydrophobicity affected protein detection. Broad recognition was obtained for enzymes involved in carbohydrate, fatty acid, amino acid and nucleotide metabolism, replication, transcription, translation, cell wall synthesis, as well as for proteins affecting bacterial functions important for industrial applications, i.e. milk sugar import and exopolysaccharide biosynthesis. By providing detailed reference electrophoretic/chromatographic maps to be used in future comparative proteomic investigations on bacteria grown under various experimental conditions or on different bacterial strains, our results will favour dedicated studies on S. thermophilus metabolism and its regulation or on detection of biomarkers for selection of optimal strains for industrial applications.
Evaluation of various DFT protocols for computing 1H and 13C chemical shifts to distinguish stereoisomers: diastereomeric 2‐, 3‐, and 4‐methylcyclohexanols as a test set
Authors: Wiitala Keith W. , Al‐Rashid Ziyad F. , Dvornikovs Vadims , Hoye Thomas R. , Cramer Christopher J. 
Published: April 2007

Abstract1H and 13C NMR chemical shifts were measured for a set of six isomers—the cis and trans 2‐, 3‐, and 4‐methylcyclohexanols. 1H and 13C NMR chemical shifts were computed at the B3LYP, WP04, WC04, and PBE1 density functional levels for the same compounds, taking into account the Boltzmann distribution among conformational isomers (chair–chair forms and hydroxyl rotamers). The experimental versus computed chemical shift values for proton and carbon were compared and evaluated (using linear correlation (r2), total absolute error (|Δδ|T), and mean unsigned error (MUE) criteria) with respect to the relative ability of each method to distinguish between cis and trans stereoisomers for each of the three constitutional isomers. For 13C shift data, results from the B3LYP and PBE1 density functionals were not sufficiently accurate to distinguish all three pairs of stereoisomers, while results using the WC04 functional did do so. For 1H shift data, each of the WP04, B3LYP, and PBE1 methods was sufficiently accurate to make the proper stereochemical distinction for each of the three pairs. Applying a linear correction to the computed data improved both the absolute accuracy and the degree of discrimination for most of the methods. The nature of the cavity definition used for continuum solvation had little effect. Overall, use of proton chemical shift data was more discriminating than use of carbon data. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of oligomeric urethane dimethacrylates with carboxylic groups and their testing in dental composites
Authors: Buruiana Emil C. , Buruiana Tinca , Melinte Violeta , Zamfir Mirela , Colceriu Aurora , Moldovan Marioara 
Published: April 2007

AbstractCarboxyl urethane dimethacrylate oligomers with poly(ethylene oxide) sequences in the structure were synthesized and examined in photopolymerizable resins that could better adhere to various kinds of materials, including tooth substrates. Aspects of the morphogenesis of dental composites formed through a photochemically initiated radical copolymerization of the carboxylic derivatives, in addition to other partners encountered frequently in such materials, were studied comparatively with the corresponding urethane dimethacrylate monomer. The effect of a small quantity of a carboxylic macromer (ca. 10%) on the formation of a network with a non‐carboxyl urethane dimethacrylate oligomer (90%) as a potential substitute for diglycidyl methacrylate of bisphenol A and a filler (1/1 70% Aerosil/glass) was visualized by fluorescence spectroscopy with a pyrene methanol probe. The results showed the following: (1) the degree of conversion in the formulations into which carboxyl urethane dimethacrylate was incorporated decreased with increasing poly(ethylene oxide) chain length, (2) the formation of excimers was inhibited in the derived composites, and (3) an important quenching of the monomer fluorescence emission with the UV–vis irradiation time was observed in the formulation containing a filler (Aerosil+Zr/Sr glass). Preliminary testing of the resin composites suggested that all urethane oligomers containing carboxylic acid could lead to dental materials with reduced polymerization shrinkage and good mechanical properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1956–1967, 2007