bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and evaluation of liquid amine‐terminated polybutadiene rubber and its role in epoxy toughening
Authors: Kar Sritama , Banthia Ajit K. 
Published: April 2005

AbstractEpoxy resin is widely used for coatings, adhesives, castings, electrical insulation materials, and other applications. However, unsolved problems still remain in its applications. The main problem is low toughness: cured epoxy resin is rather brittle, with poor resistance to the propagation of cracks derived from the internal stress generated by shrinkage in the cooling process from cure temperature to room temperature. The objective of this study was to improve the flexibility and toughness of diglycidyl ether of bisphenol A based epoxy resin with a liquid rubber. For this purpose, amine‐terminated polybutadiene (ATPB) was synthesized. The product was characterized by Fourier transform infrared and NMR spectroscopy and elemental analysis. ATPB‐modified epoxy networks were made by curing with an ambient‐temperature curing agent, triethylene tetramine. We varied the epoxy/liquid rubber compositions to study the effect of toughener concentration on the impact and thermal properties. Higher mechanical properties were obtained for epoxy resins toughened with 1 phr ATPB. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2446–2453, 2005
A concise peer into the background, initial thoughts and practices of human gene therapy
Authors: Gonçalves Manuel A.F.V. 
Published: April 2005

AbstractThe concept of human gene therapy came on the heels of fundamental discoveries on the nature and working of the gene. However, realistic prospects to correct the underlying cause of recessive genetic disorders through the transfer of wild‐type alleles of defective genes had to wait for the arrival of recombinant DNA technology. These techniques permitted the isolation and insertion of genes into the first recombinant delivery systems. The realization that viruses are natural gene carriers provided inspiration for gene therapy and, as engineered vectors, viruses became prominent gene delivery vehicles. Nonetheless, when put in the context of human and non‐human primate studies, all vectors fell short of success regardless of their viral or non‐viral origin. Recognition of issues such as inefficient gene transfer and short‐lived or scant expression in the relevant cell type(s) prompted researchers to refine and develop several gene delivery systems, in particular those based on retroviruses, adeno‐associated viruses and adenoviruses. Concomitantly, available technology was deployed to tackle disorders that require few genetically corrected cells to attain therapy. BioEssays 27: 506–517, 2005. © 2005 Wiley periodicals, Inc.
Suicidal genetically engineered microorganisms for bioremediation: Need and perspectives
Authors: Paul Debarati , Pandey Gunjan , Jain Rakesh K. 
Published: April 2005

AbstractIn the past few decades, increased awareness of environmental pollution has led to the exploitation of microbial metabolic potential in the construction of several genetically engineered microorganisms (GEMs) for bioremediation purposes. At the same time, environmental concerns and regulatory constraints have limited the in situ application of GEMs, the ultimate objective behind their development. In order to address the anticipated risks due to the uncontrolled survival/dispersal of GEMs or recombinant plasmids into the environment, some attempts have been made to construct systems that would contain the released organisms. This article discusses the designing of safer genetically engineered organisms for environmental release with specific emphasis on the use of bacterial plasmid addiction systems to limit their survival thus minimizing the anticipated risk. We also conceptualize a novel strategy to construct “Suicidal Genetically Engineered Microorganisms (SGEMs)” by exploring/combining the knowledge of different plasmid addiction systems (such as antisense RNA‐regulated plasmid addiction, proteic plasmid addiction etc.) and inducible degradative operons of bacteria. BioEssays 27:563–573, 2005. © 2005 Wiley Periodicals, Inc.
The three‐sided romance of the lateral line: Glia love axons love precursors love glia
Authors: Ghysen Alain , Dambly‐Chaudière Christine 
Published: April 2005

AbstractThe lateral line system of fish and amphibians is closely related to the inner ear in terms of evolution, morphology and physiology. Several recent papers have shed new light on the postembryonic development of this system, and have revealed an unexpected triangular relationship where migrating sensory precursors guide axons, axons guide glia and glia, in turn, control the formation of sensory organs. They have also revealed the crucial importance of controlled cell migration not only for patterning the system, but also for determining polarity (and therefore directional sensitivity) of the mechanosensory hair cells. The remarkable accessibility of the lateral line system may allow a detailed analysis of cell migration and polarization, and may help us better understand the complex interactions between sensory precursor cells, neurons and glia during development. BioEssays 27:488–494, 2005. © 2005 Wiley Periodicals, Inc.
A metabolic enzyme doing double duty as a transcription factor
Authors: Bhardwaj Anjana , Wilkinson Miles F. 
Published: April 2005

AbstractMany kinds of multifunctional regulatory proteins have been identified that perform distinct biochemical functions in the nucleus, the cytoplasm, or both. Here we describe the recent discovery by Hall et al. (2004)1 of a new type of multifunctional protein: a metabolic enzyme that doubles as a transcription factor. This enzyme, Arg5,6, functions as a catalytic enzyme in ornithine biosynthesis and also binds and regulates the promoters of nuclear and mitochondrial genes. It may also regulate precursor mRNA metabolism. We discuss how proteins that serve as both metabolic enzymes and transcription factors might have evolved. BioEssays 27:467–471, 2005. © 2005 Wiley Periodicals, Inc.
Helix packing motif common to the crystal structures of two undecapeptides containing dehydrophenylalanine residues: Implications for the de novo design of helical bundle super secondary structural modules
Authors: Rudresh  , Gupta Madhvi , Ramakumar Suryanarayanarao , Chauhan Virander S. 
Published: April 2005

AbstractDe novo designed peptide based super secondary structures are expected to provide scaffolds for the incorporation of functional sites as in proteins. Self‐association of peptide helices of similar screw sense, mediated by weak interactions, has been probed by the crystal structure determination of two closely related peptides: Ac–Gly1–Ala2–Δ Phe3–Leu4–Val5–ΔPhe6–Leu7–Val8–ΔPhe9–Ala10–Gly11–NH2 (I) and Ac–Gly1–Ala2–ΔPhe3–Leu4–Ala5–ΔPhe6–Leu7–Ala8–ΔPhe9–Ala10–Gly11–NH2 (II). The crystal structures determined to atomic resolution and refined to R factors 8.12 and 4.01%, respectively, reveal right‐handed 310‐helical conformations for both peptides. CD has also revealed the preferential formation of right‐handed 310‐helical conformations for both molecules. Our aim was to critically analyze the packing of the helices in the solid state with a view to elicit clues for the design of super secondary structural motifs such as two, three, and four helical bundles based on helix–helix interactions. An important finding is that a packing motif could be identified common to both the structures, in which a given peptide helix is surrounded by six other helices reminiscent of transmembrane seven helical bundles. The outer helices are oriented either parallel or antiparallel to the central helix. The helices interact laterally through a combination of NH · · · O, CH · · · O, and CH · · · π hydrogen bonds. Layers of interacting leucine residues are seen in both peptide crystal structures. The packing of the peptide helices in the solid state appears to provide valuable leads for the design of super secondary structural modules such as two, three, or four helix bundles by connecting adjacent antiparallel helices through suitable linkers such as tetraglycine segments. © 2005 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 80: 617–627, 2005This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Adsorption of 6‐mercaptopurine and 6‐mercaptopurine‐ribosideon silver colloid: A pH‐dependent surface‐enhanced Raman spectroscopy and density functional theory study. II. 6‐mercaptopurine‐riboside
Authors: Szeghalmi A. V. , Leopold L. , Pînzaru S. , Chis V. , Silaghi‐Dumitrescu I. , Schmitt M. , Popp J. , Kiefer W. 
Published: April 2005

AbstractSurface‐enhanced Raman spectroscopy (SERS) has been applied to characterize the interaction of 6‐mercaptopurine‐ribose (6MPR), an active drug used in chemotherapy of acute lymphoblastic leukemia, with a model biological substrate at therapeutic concentrations and as function of the pH value. Therefore, a detailed vibrational analysis of crystalline and solvated (6MPR) based on Density Functional Theory (DFT) calculations of the thion and thiol tautomers has been performed. 6MPR adopts the thion tautomeric form in the polycrystalline state. The SERS spectra of 6MPR and 6‐mercaptopurine (6MP) recorded on silver colloid provided evidence that the ribose derivative shows different adsorption behavior compared with the free base. Under acidic conditions, the adsorption of 6MPR on the metal surface via the N7 and possibly S atoms was proposed to have a perpendicular orientation, while 6MP is probably adsorbed through the N9 and N3 atoms. Under basic conditions both molecules are adsorbed through the N1 and possibly S atoms, but 6MP has a more tilted orientation on the silver colloidal surface while 6MPR adopts a perpendicular orientation. The reorientation of the 6MPR molecule on the surface starts at pH 8 while in the case of 6MP the reorientation starts around pH 6. Under basic conditions, the presence of the anionic molecular species for both molecules is suggested. The deprotonation of 6MP is completed at pH 8 while the deprotonation of the riboside is finished at pH 10. For low drug concentrations under neutral conditions and for pH values 8 and 9, 6MPR interacts with the substrate through both N7 and N1 atoms, possibly forming two differently adsorbed species, while for 6MP only one species adsorbed via N1 was evidenced. © 2005 Wiley Periodicals, Inc. Biopolymers 78: 298–310, 2005This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Design, Synthesis, and Photodegradation of Silicon‐Containing Polyureas
Authors: Hwu Jih Ru , King Ke Yung 
Published: April 2005

AbstractNovel N‐phenyl aromatic polyureas containing bis[(N,N′‐diphenylureylene)methyl]silane units in the skeleton were designed as a new type of photodegradable polymer. These materials were successfully prepared in 88–93 % yields by copolymerization of bis(anilinomethyl)dimethylsilane and dianilino‐p‐xylene with 4,4′‐methylenebis(phenylisocyanate). Their photodegradability was found to be 10.1 times higher than that of polymers of similar structure, but lacking the silyl unit. Furthermore, the photodegradation mechanism of polyureas was elucidated, and involves single‐electron transfer between silyl and carbonyl groups, silyl group migration, and solvolysis. These novel polymers are potential materials of high economic value for use in photolithography and microelectronics.
Selenium‐Catalyzed Reductive Carbonylation of 2‐Nitrophenols to2‐Benzoxazolones
Authors: Wang Xiaofang , Ling Gang , Xue Yan , Lu Shiwei 
Published: April 2005

Abstract2‐Benzoxazolones or 2‐benzimidazolones are synthesized in moderate to good yields in the presence of a base (KOH, NaOH, KOAc, NEt3, DBU) at atmospheric pressure or under a high pressure of CO by one‐pot reductive carbonylation of 2‐nitrophenols or 2‐nitroaniline in the presence of selenium as catalyst. Besides the effect of base, the effects of solvent and temperature on the reaction were investigated at high or atmospheric pressure. Contrasting results were obtained for 2‐benzoxazolones or 2‐benzimidazolone at high and atmospheric pressures. Moreover, phase‐transfer catalysis was exhibited. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Enantioselective Protonation of the Lithium Transient Enolate of2‐Methyltetralone with 2‐Sulfinyl Alcohols
Authors: Gil Jesús , Medio‐Simon Mercedes , Mancha Gisela , Asensio Gregorio 
Published: April 2005

AbstractA new catalytic cycle for the enantioselective protonation of cyclic ketone enolates with sulfinyl alcohols has been developed. An enol trifluoroacetate that can be easily obtained from the corresponding ketone is used for the first time as an enolate precursor of a cyclic ketone enolate. In this method, the achiral alcohol plays two roles: it is involved, as is usual in catalytic asymmetric protonation reactions, in the turnover of the chiral proton source and also in the generation of a transient enolate through the reaction of its corresponding alkoxide with the enol trifluoroacetate precursor. Stereoselectivity is highly dependent on the structure of the achiral alcohol. High levels of stereoselectivity can be achieved with the use of cyclohexanol. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Investigation of Diketopiperazines Containing a Guanidino‐Functionalized Sidechain as Potential Catalysts of Enantioselective Strecker Reactions
Authors: Becker Christian , Hoben Christine , Schollmeyer Dieter , Scherr Günther , Kunz Horst 
Published: April 2005

AbstractDiketopiperazine 1 consisting of L‐(γ‐guanidino‐α‐amino)butyric acid and L‐phenylalanine was synthesized as the hydroacetate and as the hydronitrate. Its structure was confirmed by X‐ray analysis. In contrast to reports in the literature (Lipton et al.), compound 1 does not induce enantioselevtive catalysis of Strecker reactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Removal of Heavy Metals by Waste Tea Leaves from Aqueous Solution
Authors: Ahluwalia S. S. , Goyal D. 
Published: April 2005

AbstractIn this paper, tea leaves were shown to be an effective, low‐cost biosorbent. Removal of lead, iron, zinc and nickel from 20 mg/L metal solution by dried biomass of waste tea leaves amounted to 96, 91, 72 and 58 %, respectively, at equilibrium, which followed Langmuir and Freundlich adsorption isotherms. Adsorption of metal was in the order of Pb > Fe > Zn > Ni from 5–100 mg/L of metal solution. From a multi‐metallic mixture, 92.5, 84 and 73.2 % of lead, iron and zinc, respectively, were removed. Fourier transform infrared (FTIR) studies indicated that the carboxyl group was involved in the binding of lead and iron, whereas the amine group was involved in the binding of nickel and zinc. A flow through sorption column packed with dried biomass demonstrated a sorption capacity of 73 mg Pb/g of biomass, indicating its potential in cleaning metal containing wastewater. The metal laden biomass obtained could be disposed off by incineration.
Chromate reduction in wastewater at different pH levels using thin iron wires—A laboratory study
Authors: Chang Li‐Yang 
Published: April 2005

AbstractThe effectiveness of using thin zero‐valent iron (Fe0) wires in the treatment of wastewater generated from a metal cleaning facility and with a pH in the range of 2 to 10 was examined. It was found that (1) when the sample containing low levels of total chromium (≤14 mg/L) was mixed with iron wires at a pH of 3 to 8, 50 to 90% of the total chromium could be reduced in 4 h; (2) the initial reduction efficiency was pH‐dependent: the lower the pH, the higher the reduction rate; (3) variations of solution pH, redox electrical potential, and electrical conductivity (EC) in samples were also pH‐dependent; (4) the adsorption/reduction efficiency was limited by the diffusion of Cr(VI) from wastewater to the iron surface when the test duration was long; (5) when the initial pH = 3, iron corrosion and redox reaction dominated the reduction process; however, with pH = 8 or 10, corrosion, surface passivation, or metal precipitation could compete with reduction; (6) the used iron wires were still effective in chromium removal in new samples at pH = 3; and (7) some desorption of adsorbed chromium was observed in acidic samples when the test duration was long. Scanning electron microscope images and energy‐dispersive X‐ray spectra collected from iron samples also indicate that the efficiency of chromium adsorption/reduction is pH‐dependent. Our results suggest that using zero‐valent iron to polish acidic wastewater containing low contents of chromium and other heavy metals is feasible. © 2005 American Institute of Chemical Engineers Environ Prog, 2005
Testing the unbiased forward exchange rate hypothesis using a Markov switching model and instrumental variables
Authors: Spagnolo Fabio , Psaradakis Zacharias , Sola Martin 
Published: April 2005

AbstractThis paper develops a model for the forward and spot exchange rate which allows for the presence of a Markov switching risk premium in the forward market and considers the issue of testing the unbiased forward exchange rate (UFER) hypothesis. Using US/UK data, it is shown that the UFER hypothesis cannot be rejected, provided that instrumental variables are used to account for within‐regime correlation between explanatory variables and disturbances in the Markov switching model on which the test is based. Copyright © 2005 John Wiley & Sons, Ltd.
Site‐directed mutations (Asp405Ile and Glu124Ile) in cytochrome P450scc: Effect on adrenodoxin binding
Authors: Ghisellini Paola , Paternolli Cristina , Nicolini Claudio 
Published: April 2005

AbstractCytochrome P450scc, mitochondrial adrenodoxin (Adx), and adrenodoxin reductase (AdR) are an essential components in a steroid hydroxylation system. In particular, mytochondrial cytochrome P450scc enzyme catalyses the first step in steroid hormones biosynthesis, represented by the conversion of cholesterol to pregnenolone. In order to study the effect of single mutations on the Adx binding a model of bovine cytochrome P450scc, previously optimized by molecular modeling, was utilized. It was hypothesized by molecular docking that two residues (Asp405 and Glu124) are involved in Adx binding. By site‐directed mutagenesis, two mutants of cytochrome P450scc (Asp405Ile and Glu124Ile) expressed in Escherichia coli, were realized by replacing with isoleucines. The site‐directed mutations effect on Adx binding was evaluated by differential spectral titration. The apparent dissociation constant values for Asp405Ile and Glu124Ile cytochrome P450scc show that the mutated residues seem to be at the interaction domain with Adx or at least close to it, as predicted by molecular modeling study. Finally, the engineered enzymes were characterized by biochemical and biophysical techniques such as circular dichroism (CD), UV/Vis spectroscopy, and electrochemical analysis. © 2005 Wiley‐Liss, Inc.
Biological evaluation of penetration domain and killing domain peptides
Authors: Jarajapu Y. P. R. , Baltunis J. , Knot H. J. , Sullivan S. M. 
Published: April 2005

AbstractBackgroundCancer gene therapy must impact the majority of cells to be effective. Current gene delivery systems are unable to achieve sufficient transfer efficiency to the tumor cells. Cell killing can be dramatically increased through a bystander effect. Modeling the gene product with synthetic peptides can identify key elements for creating cell killing through a bystander effect.MethodsFluorescent labeled peptides were used for uptake kinetic studies and determination of intracellular localization in human glioblastoma cell lines, rat glioma cells lines and pressurized rat cerebral arteries. The degree of cell killing was assayed using propidium iodide coupled with fluorescence‐activated cell sorting (FACS) analysis.ResultsPeptides derived from HIV Tat and Drosophila antennapedia homeodomain were taken up by all tumor and primary cells. Attachment of an Mdm‐2‐binding domain derived from P14ARF resulted in cell killing and was independent of domain orientation. Uptake kinetics showed rapid uptake for both tumor and primary cells equilibrating with the external media within 10 min. Intraluminal or extraluminal administration of peptides into pressurized cerebral arteries showed a lack of extravasation across the subbasement lamina. Assay of biological activity following intraluminal administration showed selective suppression of response to vasodilation with no effect on response by smooth muscle cells.ConclusionsThe results from these studies identified: (1) a cell trafficking domain and a cytotoxic domain for killing brain tumor cells; (2) that cell killing was independent of the domain orientations with regard to the cell trafficking domain being at the C‐terminus or N‐terminus; and (3) that the dual domain peptide can also be taken up by endothelial cells as shown by the cerebral artery studies. Hence, localized expression of the cytotoxic gene has the potential to not only kill brain tumor cells, but also tumor endothelium, thus further increasing the effectiveness of the therapy. Copyright © 2005 John Wiley & Sons, Ltd.
Some historical and scientific issues related to research on emotional intelligence
Authors: Landy Frank J. 
Published: April 2005

AbstractIn the past decade, the concept of emotional intelligence (EI) has emerged as a potential new construct for explaining behavioral variance not accounted for by traditional measures of general academic intelligence or personality. EI researchers credit E. L. Thorndike as the first to propose such a construct when he suggested that social intelligence is independent of abstract or academic intelligence. The current paper traces the historical roots of social intelligence and the current scientific status of emotional intelligence. It appears that emotional intelligence, as a concept related to occupational success, exists outside the typical scientific domain. Much of the data necessary for demonstrating the unique association between EI and work‐related behavior appears to reside in proprietary databases, preventing rigorous tests of the measurement devices or of their unique predictive value. For those reasons, any claims for the value of EI in the work setting cannot be made under the scientific mantle. Copyright © 2005 John Wiley & Sons, Ltd.
Rumors of the death of emotional intelligence in organizational behavior are vastly exaggerated
Authors: Ashkanasy Neal M. , Daus Catherine S. 
Published: April 2005

AbstractIn the first of two articles presenting the case for emotional intelligence in a point/counterpoint exchange, we present a brief summary of research in the field, and rebut arguments against the construct presented in this issue. We identify three streams of research: (1) a four‐branch abilities test based on the model of emotional intelligence defined in Mayer and Salovey (1997); (2) self‐report instruments based on the Mayer–Salovey model; and (3) commercially available tests that go beyond the Mayer–Salovey definition. In response to the criticisms of the construct, we argue that the protagonists have not distinguished adequately between the streams, and have inappropriately characterized emotional intelligence as a variant of social intelligence. More significantly, two of the critical authors assert incorrectly that emotional intelligence research is driven by a utopian political agenda, rather than scientific interest. We argue, on the contrary, that emotional intelligence research is grounded in recent scientific advances in the study of emotion; specifically regarding the role emotion plays in organizational behavior. We conclude that emotional intelligence is attracting deserved continuing research interest as an individual difference variable in organizational behavior related to the way members perceive, understand, and manage their emotions. Copyright © 2005 John Wiley & Sons, Ltd.