bluuebunny/crossref_metadata_2025_split huggingface dataset:
Utilization of a new biotinylation reagent in the development of a nondiscriminatory investigative approach for the study of cell surface proteins
Authors: Gauthier Daniel J. , Gibbs Bernard F. , Rabah Nadia , Lazure Claude 
Published: November 2004

AbstractIn order to circumvent the various problems encountered during the study of membrane‐bound proteins, we designed and synthesized a novel membrane‐impermeable biotinylation reagent incorporating chemical properties compatible with this goal. We then developed a nondiscriminatory analytical procedure for such studies which overcomes possible selectivity, contamination and solubility problems. The necessary steps (labeling, limited in situ proteolysis, affinity purification) are all conducted in mild or near native conditions. This versatile method could provide an accurate picture of the cell surface proteome.
Quantitative protein profiling using antibody arrays
Authors: Barry Richard , Soloviev Mikhail 
Published: November 2004

AbstractTraditional approaches to microarrays rely on direct binding assays where the extent of hybrid‐isation and the signal detected are a measure of the analyte concentration in the experimental sample. This approach, directly imported from the nucleic acid field, may fail if applied to antibody‐antigen interactions due to the shortage of characterised antibodies, the significant heterogeneity of antibody affinities, their dependence on the extent of protein modification during labelling and the inherent antibody cross‐reactivity. These problems can potentially limit the multiplexing capabilities of protein affinity assays and in many cases rule out quantitative protein profiling using antibody microarrays. A number of approaches aimed at achieving quantitative protein profiling in a multiplex format have been reported recently. Of those reported, the three most promising routes include signal amplification, multicolour detection and competitive displacement approaches to multiplex affinity assays. One in particular, competitive displacement, also overcomes the problems associated with quantitation of affinity interactions and provides the most generic approach to highly parallel affinity assays, including antibody arrays.
Proteome analysis of human substantia nigra in Parkinson's disease
Authors: Basso Manuela , Giraudo Sabrina , Corpillo Davide , Bergamasco Bruno , Lopiano Leonardo , Fasano Mauro 
Published: November 2004

AbstractProtein expression has been compared in human substantia nigra specimens from Parkinson's disease (PD) patients and from controls, and 44 proteins expressed in this midbrain region were identified by peptide mass fingerprinting. Among them, nine showed changes in their abundance. L and M neurofilament chains are less abundant in PD specimens, whereas peroxiredoxin II, mitochondrial complex III, ATP synthase D chain, complexin I, profilin, L‐type calcium channel δ‐subunit, and fatty‐acid binding protein are significantly more present in PD samples than in controls. Besides the consolidated view of oxidative stress involvement in PD pathogenesis, suggested by overexpression of mitochondrial and reactive oxygen species (ROS)‐scavenging proteins, these results indicate a possible potentiation mechanism of afferent signals to substantia nigra following degeneration of dopaminergic neurons.
Challenges in mass spectrometry‐based proteomics
Authors: Reinders Joerg , Lewandrowski Urs , Moebius Jan , Wagner Yvonne , Sickmann Albert 
Published: November 2004

AbstractDuring the last decade, protein analysis and proteomics have been established as new tools for understanding various biological problems. As the identification of proteins after classical separation techniques, such as two‐dimensional gel electrophoresis, have become standard methods, new challenges arise in the field of proteomics. The development of “functional proteomics” combines functional characterization, like regulation, localization and modification, with the identification of proteins for deeper insight into cellular functions. Therefore, different mass spectrometric techniques for the analysis of post‐translational modifications, such as phosphorylation and glycosylation, have been established as well as isolation and separation methods for the analysis of highly complex samples, e.g. protein complexes or cell organelles. Furthermore, quantification of protein levels within cells is becoming a focus of interest as mass spectrometric methods for relative or even absolute quantification have currently not been available.Protein or genome databases have been an essential part of protein identification up to now. Thus, de novo sequencing offers new possibilities in protein analytical studies of organisms not yet completely sequenced.The intention of this review is to provide a short overview about the current capabilities of protein analysis when addressing various biological problems.
Increases in leukocyte cluster of differentiation antigen expression during cardiopulmonary bypass in patients undergoing heart transplantation (vol. 4, Issue 7, pp. 1918‐1926)
Authors: Lal Sean , Lui Rodney , Nguyen Lisa , Macdonald Peter , Denyer Gareth , dos Remedios Cristobal 
Published: November 2004

AbstractSee original http://dx.doi.org/10.1002/pmic.200300756
Block copolymers of acrylic acid and butyl acrylate prepared by reversible addition–fragmentation chain transfer polymerization: Synthesis, characterization, and use in emulsion polymerization
Authors: Gaillard Nicolas , Guyot Alain , Claverie Jerome 
Published: November 2004

AbstractAmphiphilic block copolymers of poly(acrylic acid‐b‐butyl acrylate) were prepared by reversible addition–fragmentation chain transfer polymerization in a one‐pot reaction. These copolymers were characterized by NMR, static and dynamic light scattering, tensiometry, and size exclusion chromatography. The aggregation characteristics of the copolymers corresponded to those theoretically predicted for a star micelle. In a butyl acrylate and methyl methacrylate emulsion polymerization, low amounts of these copolymers could stabilize latices with solid contents up to 50%. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 684–698, 2003
Real‐time Fourier transform infrared study of free‐radical UV‐induced polymerization of hybrid sol–gel. I. Effect of silicate backbone on photopolymerization kinetics
Authors: Soppera O. , Croutxé‐Barghorn C. 
Published: November 2004

AbstractFree‐radical photocurable hybrid sol–gel materials have gained special interest. They are becoming more and more widely used for applications in coatings, optics, sensors, catalysis, and so forth. The photochemical step is a fundamental step in the elaboration of this kind of hybrid sol–gel. However, little is known about the specifics of the photochemistry in this material. The relation between the organic and the inorganic part is investigated. Hydrolysis and condensation reactions were characterized by 29Si NMR. A precise description of the material before irradiation is of paramount importance to understand photoinduced phenomena. Real‐time Fourier transform infrared spectroscopy was used to examine the photopolymerization of hybrid sol–gel under UV irradiation. UV photopolymerization occurred efficiently in hybrid sol–gel although inhibition of free‐radical polymerization by molecular oxygen was pronounced. Important structural modifications during irradiation were also measured. They concern both inorganic and organic parts of the hybrid material. The condensation state of the silicate network was of crucial importance. The presence of the silicate backbone did not limit the final conversion ratio. On the contrary, photopolymerization occurred more efficiently for systems with a higher degree of condensation. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 716–724, 2003
Synthesis and thermal behavior of phenylethynyl‐terminated linear and hyperbranched polyphenylquinoxalines
Authors: Baek Jong‐Beom , Harris Frank W. 
Published: November 2004

AbstractA phenylquinoxaline (PQ) AB monomer mixture was treated with monofunctional and difunctional end‐capping agents and with and without a coupling agent to afford phenylethynyl‐terminated linear PQ oligomers. The resulting PQ oligomers were soluble in common organic solvents and had intrinsic viscosities (IVs) of 0.21–0.30 dL/g. The glass‐transition temperature (Tg) of the diphenylethynyl‐end‐capped PQ oligomer on both sides increased the most, from 215 °C (before curing) to 251 °C (after curing). The PQ AB2 monomer, which acted as both a coupling agent and a monomer for the hyperbranched polymer, was treated with an AB monomer and end‐capping agents to afford phenylethynyl‐terminated hyperbranched polyphenylquinoxalines (PPQs). They were also soluble in common organic solvents, had IVs of 1.00–1.65 dL/g and Tg's of 251–253 °C, and underwent exothermic cure with maxima around 412–442 °C. The Tg's of the cured hyperbranched PPQs ranged from 258 to 261 °C, depending on the number of phenylethynyl groups on the surface. After further curing, they displayed a Tg of 316 °C in one sample and turned into a fully crosslinked network. The dynamic melt viscosities of a linear oligomer (IV = 0.21 dL/g), a hyperbranched sample (IV = 1.00 dL/g), and a linear reference PPQ (IV = 1.29 dL/g) were compared with respect to the processing temperature. The PQ oligomer and hyperbranched PPQ had low melt viscosities. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 6318–6330, 2004
Thianthrene as an activating group for the synthesis of poly(aryl ether thianthrene)s by nucleophilic aromatic substitution
Authors: Edson Joseph B. , Knauss Daniel M. 
Published: November 2004

AbstractA method for the preparation of poly(aryl ether thianthrene)s has been developed in which the aryl ether linkage is generated in the polymer‐forming reaction. The thianthrene heterocycle is sufficiently electron‐withdrawing to allow fluoro displacement with phenoxides by nucleophilic aromatic substitution. The monomer for this reaction, 2,7‐difluorothianthrene, can be synthesized in a moderate yield by a simple reaction sequence. Semiempirical calculations at the PM3 level suggest that 2,7‐difluorothianthrene is sufficiently activated, whereas NMR spectroscopy (1H and 13C) indicates that the monomer is only slightly activated or (19F) not sufficiently activated for nucleophilic aromatic substitution. Model reactions with p‐cresol have demonstrated that the fluorine atoms on 2,7‐difluorothianthrene are readily displaced by phenoxides in high yields, and the process has been deemed suitable for polymer‐forming reactions. High‐molecular‐weight polymers have been produced from bisphenol A, bisphenol AF, and 4,4′‐biphenol. The polymers have been characterized with gel permeation chromatography, NMR spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. The glass‐transition temperatures for the polymers of different compositions and molecular weights range from 138 to 181 °C, and all the polymers have shown high thermooxidative stability, with 5% weight loss values in an air environment approaching 500 °C. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 6353–6363, 2004
Controlled polymerization of N‐isopropylacrylamide with an activated methacrylic ester
Authors: Savariar Elamprakash N. , Thayumanavan S. 
Published: November 2004

AbstractA copolymer of N‐isopropylacrylamide with the N‐hydroxysuccinimide ester of methacrylic acid has found use in a variety of applications. Here we report our efforts to gain control over the molecular weight distribution of this copolymer with controlled radical polymerization methods, such as atom transfer radical polymerization, reversible addition–fragmentation transfer (RAFT), and nitroxide‐mediated polymerization. We have found that RAFT is capable of affording these copolymers with a polydispersity index of 1.1–1.2. Our results for all three polymerizations are reported. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 6340–6345, 2004
Brominated poly(isobutylene‐co‐para‐methylstyrene) (BIMS)‐clay nanocomposites: Synthesis and characterization
Authors: Maiti Madhuchhanda , Sadhu Susmita , Bhowmick Anil K. 
Published: November 2004

AbstractIn this work, preparation and properties of different nanoclays modified by organic amines (octadecyl amine, a primary amine, and hexadecyltrimethylammonium bromide, a tertiary amine) and brominated polyisobutylene‐co‐paramethylstyrene (BIMS)‐clay nanocomposites are reported. The clays and the rubber nanocomposites have been characterized with the help of Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X‐ray diffraction (XRD). The X‐ray diffraction peaks observed in the range of 3 °–10 ° for the modified clays disappear in the rubber nanocomposites. TEM photographs show predominantly exfoliation of the clays in the range of 12 ± 4 nm in the BIMS. In the FTIR spectra of the nanocomposites, there are common peaks of virgin rubber as well as those of the clays. Excellent improvement in mechanical properties like tensile strength, elongation at break, and modulus is observed on incorporation of the nanoclays in the BIMS. Structure‐property correlation in the above nanocomposites is attempted. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4489–4502, 2004
Poly(methyl silsesquioxane)/amphiphilic block copolymer hybrids and their porous derivatives: Poly(styrene‐block‐acrylic acid) and poly(styrene‐block‐3‐trimethoxysilylpropyl methacrylate)
Authors: Chang Yung , Chen Ching‐Yi , Chen Wen‐Chang 
Published: November 2004

AbstractPorous poly(methyl silsesquioxane) (PMSSQ) films were prepared from PMSSQ/amphiphilic block copolymer (ABC) hybrids, and this was followed by spin coating and multistep baking. The ABCs were poly(styrene‐block‐acrylic acid) (PS‐b‐PAA) and poly(styrene‐block‐3‐trimethoxysilylpropyl methacrylate) (PS‐b‐PMSMA), which were synthesized by living polymerization. The chemical bonding between the ABCs and PMSSQ resulted in significant differences in the morphologies and properties of the hybrids and their porous derivatives. Both intramolecular and intermolecular hydrogen bonding existed in the PMSSQ/PS‐b‐PAA hybrid and led to macrophase separation. Through the modification of the chemical structure from the poly(acrylic acid) segment to PMSMA, covalent bonding between PMSSQ and PMSMA occurred and prevented the macrophase separation and initial pyrolysis of the ABC. Modulated differential scanning calorimetry results also suggested a significant difference in the miscibility of the two hybrid systems. The chemical bonding resulted in higher retardation of the symmetry‐to‐nonsymmetry SiOSi structural transformation for PMSSQ/PS‐b‐PMSMA than for PMSSQ/PS‐b‐PAA according to Fourier transform infrared studies. The pore size of the nanoporous thin film from the PMSSQ/PS‐b‐PMSMA hybrid was estimated by transmission electron microscopy to be less than 15 nm. The refractive index and dielectric constant of the prepared porous films decreased from 1.354 to 1.226 and from 2.603 to 1.843 as the PS‐b‐PMSMA loading increased from 0 to 50 wt %, respectively. This study suggests that chemical bonding in hybrid materials plays a significant role in the preparation of low‐dielectric‐constant nanoporous films. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4466–4477, 2004
Evaluating relief valve reliability when extending the test and maintenance interval
Authors: Urbanik Stanley A. 
Published: November 2004

AbstractPresently, more and more programs appear that provide processes for evaluating and extending the time between major process shutdowns and maintenance. RBI (risk‐based inspections) and Six Sigma processes are two examples of methods currently in use to help drive shutdown extension programs. The relief valves on these processes often go along with the shutdown extension programs without a thorough understanding of the impact on relief valve reliability. Using an analysis for a “stand‐by system,” the change in PFD (probability of failure on demand) of the relief system as a function of change in test interval is shown. Human error is another factor that compromises relief valve reliability. Some arguments are offered that suggest reduced inspections increase reliability because there are fewer opportunities for human error. This study addresses the human error question and shows that the human error contribution is constant while the relief valve is in service. Finally, the increase in PFD when increasing the test interval is discussed in terms of the potential increase in risk. The increased risk as a percentage change should be communicated and understood by those deciding to extend shutdown intervals. © 2004 American Institute of Chemical Engineers Process Saf Prog 23: 191–196, 2004
Protection Survivability Importance in Systems with Multilevel Protection
Authors: Levitin Gregory 
Published: November 2004

AbstractThis paper considers systems that can have different states corresponding to different combinations of available elements constituting the system. Each state can be characterized by a performance rate, which is the quantitative measure of a system's ability to perform its task. Both the impact of external factors (attack) and internal causes (failures) affect system survivability, which is determined as the probability of meeting a given demand. In order to increase the system's survivability a multilevel protection is applied to its subsystems. This means that a subsystem and its inner level of protection are in turn protected by the protection of an outer level. This double‐protected subsystem has its outer protection and so forth. In such systems, the protected subsystems can be destroyed only if all of the levels of their protection are destroyed. Each level of protection can be destroyed only if all of the outer levels of protection are destroyed. In such systems, different protections play different roles in providing for the system's survivability. The evaluation of the relative influence of the protections' survivability on the survivability of the entire system provides useful information about the importance of these protections. The protection survivability importance index is introduced in order to evaluate this influence and an algorithm for evaluating the index is presented. The relevancy of protection is also considered. Illustrative examples are presented. Copyright © 2004 John Wiley & Sons, Ltd.
Calculation of some Reliability Measures for Redundancy Systems with Different Types of Failures
Authors: Rosenhaus M. B. , Zarudny V. I. 
Published: November 2004

AbstractThe methods developed to determine some reliability measures such as mean operating time to failure, the reliability and availability functions of duplicated systems with n types of failures are discussed. These methods enable the reliability measures to be obtained directly from the state graph without solving a system of algebraic or differential equations. Copyright © 2004 John Wiley & Sons, Ltd.
Reliability Model for Polyimide–Metal Interconnect Shorts in GaAs ASICs
Authors: Strifas N. , Yalamanchili P. , Christou A. 
Published: November 2004

AbstractA physical reliability model has been developed to calculate the time to failure of polyimide–metal multilevel interconnected GaAs components due to the shorts between interconnect metallizations through a polyimide interlayer. The failure mechanism for the shorts between neighboring metals through the polyimide is described as a stress‐assisted diffusion process along a polyimide microcrack due to the combination of process defect and high thermal stress concentration. The finite element method has been used to determine the temperature increase during operation and the resulting thermal stress due to the difference in coefficients of thermal expansion (CTEs) of the materials used in the multilevel metallization GaAs module of devices. Numerical methods have been used to solve the partial differential diffusion equations with stress gradients in order to obtain the time to failure of the devices. The time to failure for the shorts between metal level 4 and metal 2 at 123 °C operating temperature was calculated to be 20 h for the conditions analyzed. The activation energy for the failure of the shorts between two level metals was calculated to be 0.48 eV. Copyright © 2004 John Wiley & Sons, Ltd.
A Petri Net Approach to Remote Diagnosis for Failures of Cardiac Pacemakers
Authors: Yang S. K. 
Published: November 2004

AbstractThis paper describes the application of Petri nets to remote diagnosis for failures of cardiac pacemakers. The operations, structures and basic control methods of the different types of cardiac pacemakers are first described. A combined synchronous pacemaker is modeled into a Petri net in this study. Twelve checkpoints are added into the modeled Petri net so as to construct a Petri net for failure diagnosis. A remote mode for failure diagnosis of implanted pacemakers is also designed by the Petri net approach. A low‐power transmitter transmits a checking‐code with 12 digits from the implanted pacemaker to the outside of the patient's body manually or automatically. By observing the markings of the checking code, the working status and the health condition of the pacemaker are clear at a glance. Applications of the Petri net method for failure diagnosis and control optimization are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
A Convenient Solid Phase Synthesis of Disubstituted Guanidines
Authors: Sandanayake Saman , Perera Senake , Ede Nicholas J. 
Published: November 2004

AbstractTMI‐isocyanate SynPhaseTM lanterns have been used in the convenient synthesis of a disubstituted guanidine library. Support‐bound isocyanate was reacted with primary amines and the resulting urea derivatives were dehydrated to yield the corresponding support‐bound carbodiimides. The carbodiimides were reacted with primary, secondary or anilinic amines to form the corresponding guanidines. Convenient traceless cleavage of the products from the solid phase with 25% TFA/DCM gave the corresponding guanidines in good yield and good to excellent purity.
High Capacity Poly(ethylene glycol) Based Amino Polymers for Peptide and Organic Synthesis
Authors: Roice Michael , Johannsen Ib , Meldal Morten 
Published: November 2004

AbstractA beaded, chemically stable, high capacity amino resin for solid phase synthesis under polar and non‐polar conditions is described. By exhaustive reduction of amide carbonyl groups in PEG cross linked poly(ethylene glycol)‐poly(acrylamide) copolymer (PEGA) a significant increase in functional amino groups is obtained. Furthermore, a resin containing 90% PEG which is free of amide carbonyl groups is produced. The polymer was characterized by IR spectroscopy and the macroscopic properties of the beads were analyzed by microscopy. Excellent swelling properties in various solvents ranging from water to DCM were demonstrated. The chemical stability of the polymer in various reagents and solvents was investigated and changes in resin properties monitored by IR spectroscopy. The mechanical stability of the resin was analyzed by measurement of compressive strain. The unique three dimensional structure of the swelled polyethylene glycol network facilitate fast and unhindered diffusion of reagents and the support is excellent for synthesis of peptides or peptide mimetics, which can be produced in high yield/reaction volume. The efficacy of the new resin in solid phase synthesis was demonstrated by synthesizing an α‐MSH peptide fragment. A cyclic peptide mimetic was also synthesized on the new resin by the Cu (1) catalyzed intra molecular cyclo addition of alkyne and azide to form a triazole acting as a disulphide mimetic entity in very high yield and purity.