bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neurotrophin receptor expression in human primary retinoblastomas and retinoblastoma cell lines
Authors: Stephan Harald , Zakrzewski Johannes L. , Bölöni Réka , Grasemann Corinna , Lohmann Dietmar R. , Eggert Angelika 
Published: October 2007

AbstractBackgroundNeurotrophin receptor signaling regulates proliferation, differentiation and death of neuronal cells. Expression of Trk receptors has been implicated in the pathogenesis and prognosis of embryonal tumors, including neuroblastoma, nephroblastoma, and medulloblastoma.ProcedureWe analyzed TrkA, TrkB, TrkC, and p75 expression using semi‐quantitative RT‐PCR in 23 retinoblastomas and 8 retinoblastoma cell lines. Comparison of mRNA expression with clinical variables as well as the proliferation (PI) and apoptotic index (AI) of the tumor, was performed by Pearson correlation analysis and two‐sample t‐test.ResultsAlmost all tumor samples and cell lines demonstrated high expression of all Trk receptors. Expression of TrkB and its ligand, BDNF, was most pronounced, suggesting TrkB to be the major Trk receptor involved in retinoblastoma biology. In contrast, p75 expression was substantially reduced in a subset of tumors and cell lines, in particular compared to its expression in normal retina. Tumors with infiltrative growth demonstrated significantly lower relative levels of TrkC expression than localized tumors (P = 0.004). High expression of TrkA was associated with a higher AI (P = 0.04), and high expression of TrkC was associated with a younger age of the patients (P = 0.03). Inhibition of Trk signaling by K252a resulted in marked growth inhibition of retinoblastoma cells in vitro.ConclusionsOur findings suggest a role for neurotrophin signaling in the biology of retinoblastoma. General Trk inhibitors are effective in decreasing growth rates of retinoblastoma cells in vitro, and should be evaluated in in vivo studies. Pediatr Blood Cancer 2008;50:218–222. © 2007 Wiley‐Liss, Inc.
Role of total skin electron beam therapy for leukemia cutis in pediatric patients
Authors: Pepek Joseph M. , Paulino Arnold C. , Briones Michael A. , Marcus Robert B. , Esiashvili Natia 
Published: October 2007

AbstractThe role of radiation therapy for those with leukemia cutis, particularly pediatric patients, remains unclear. This report describes the first two cases of disseminated leukemia cutis in adolescents treated with total skin electron beam therapy. Both patients had resolution of their skin disease and significant palliation of symptoms. Total skin electron irradiation is an option for adolescents suffering from significant extramedullary leukemia involving the skin. While it is uncertain if this treatment has any improvement in disease‐free survival, the benefits of total skin electron therapy for symptom palliation should be considered. Pediatr Blood Cancer 2008;50:1054–1055. © 2007 Wiley‐Liss, Inc.
Effect of the 1BL.1RS translocation on the wheat endosperm, as revealed by proteomic analysis
Authors: Gobaa Samy , Bancel Emmanuelle , Kleijer Geert , Stamp Peter , Branlard Gérard 
Published: October 2007

AbstractThe introduction of the 1RS chromosome of rye into wheat made wheat more resistant to several pathogens. Today, this resistance has been overcome but the 1BL.1RS translocation remains interesting because of the improved yield and despite the lower rheological properties it produces. Nothing has been reported yet on the impact of rye chromatin introgression on the grain proteome of wheat. The comparison of the 2‐DE profiles of 16 doubled haploid lines, with or without the 1BL.1RS translocation, revealed quantitative and qualitative proteic variations in prolamins and other endosperm proteins. Eight spots were found specifically in lines having the 1BL.1RS translocation; 16 other spots disappeared from the same lines. Twelve spots, present in both genotypes, met the criteria for up‐ or down‐regulated spots. In translocated genotypes, a highly overexpressed spot, identified as a γ‐gliadin with nine cysteine residues, suggests that the lack of LMW‐GS induced by 1BL.1RS is counterbalanced by an overexpression of a relatively similar prolamin. Moreover, a spot that was absent from 1BL.1RS genotypes was identified as a dimeric alpha‐amylase inhibitor. It was considered to be a valuable candidate to explain the sticky dough associated with translocated cultivars.
“Living”/controlled free radical polymerization of MMA in the presence of cobalt(II) 2‐ethylhexanoate: A switch from RAFT to ATRP mechanism
Authors: Zhang Zhengbiao , Zhang Wei , Zhu Xiulin , Cheng Zhenping , Zhu Jian 
Published: October 2007

AbstractA metal complex, cobalt(II) 2‐ethylhexanoate (CEH), was added to the system of thermal‐initiated reversible addition‐fragmentation chain transfer (RAFT) polymerization of methyl methacrylate (MMA) with 2‐cyanoprop‐2‐yl 1‐dithionaphthalate (CPDN) as the RAFT agent at 115 °C. The polymerization rate was remarkably enhanced in the presence of CEH in comparison with that in the absence of CEH, and the increase of the CPDN concentration also accelerated the rate of polymerization. The polymerization in the concurrence of CPDN and CEH demonstrated the characters of “living”/controlled free radical polymerization: the number‐average molecular weights (Mn) increasing linearly with monomer conversion, narrow molecular weight distributions (Mw/Mn) and obtained PMMA end‐capped with the CPDN moieties. Meanwhile, CEH can also accelerate the rate of RAFT polymerization of MMA using the PMMA as macro‐RAFT agent instead of CPDN. Similar polymerization profiles were obtained when copper (I) bromide (CuBr)/N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine was used instead of CEH. Extensive experiments in the presence of butyl methacrylate, bis(cyclopentadienyl) cobalt(II) and cumyl dithionaphthalenoate were also conducted; similar results as those of MMA/CPDN/CEH system were obtained. A transition of the polymerization mechanism, from RAFT process without CEH addition to atom transfer radical polymerization in the presence of CEH, was possibly responsible for polymerization profiles. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5722–5730, 2007
Synthesis of poly(4‐vinylpyridine) by reverse atom transfer radical polymerization
Authors: Lewis Gregory T. , Nguyen Van , Cohen Yoram 
Published: October 2007

AbstractControlled radical polymerization of 4‐vinylpyridine (4VP) was achieved in a 50 vol % 1‐methyl‐2‐pyrrolidone/water solvent mixture using a 2,2′‐azobis(2,4‐dimethylpentanitrile) initiator and a CuCl2/2,2′‐bipyridine catalyst–ligand complex, for an initial monomer concentration of [M]0 = 2.32–3.24 M and a temperature range of 70–80 °C. Radical polymerization control was achieved at catalyst to initiator molar ratios in the range of 1.3:1 to 1.6:1. First‐order kinetics of the rate of polymerization (with respect to the monomer), linear increase of the number–average degree of polymerization with monomer conversion, and a polydispersity index in the range of 1.29–1.35 were indicative of controlled radical polymerization. The highest number–average degree of polymerization of 247 (number–average molecular weight = 26,000 g/mol) was achieved at a temperature of 70 °C, [M]0 = 3.24 M and a catalyst to initiator molar ratio of 1.6:1. Over the temperature range studied (70–80 °C), the initiator efficiency increased from 50 to 64% whereas the apparent polymerization rate constant increased by about 60%. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5748–5758, 2007
Synthesis of PS and PDMAEMA mixed polymer brushes on the surface of layered silicate and their application in pickering suspension polymerization
Authors: Yang Yongfang , Zhang Jian , Liu Li , Li Chenxi , Zhao Hanying 
Published: October 2007

AbstractAn ammonium free radical initiator was ion exchanged onto the surface of clay layers. Polystyrene (PS) and poly(2‐(dimethylamino)ethyl methacrylate) (PDMAEMA) mixed polymer brushes on the surface of clay layers were prepared by in situ free radical polymerization. PS colloid particles armored by clay layers with mixed polymer brushes were prepared by Pickering suspension polymerization. Transmission electron microscopy (TEM), atomic force microscopy (AFM), and scanning electron microscopy (SEM) were used to characterize the structure and morphology of the colloid particles. Clay layers on the surface of PS colloid particles can be observed. Because of the cationic nature of the PDMAEMA brushes the colloid particles have positive zeta potentials at low pH values. X‐ray photoelectron spectroscopy (XPS) was used to analyze the surface of the colloid particles. N1s binding energy of PDMAEMA chains on the surface of clay layers was detected by XPS. The two peaks of the N1s binding energy indicate two different nitrogen environments on the surface of clay layers. The peak with a lower binding energy is characteristic of neutral nitrogen on PDMAEMA chains, and the peak with a higher binding energy is attributed to protonated nitrogen on PDMAEMA chains. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5759–5769, 2007
Fluorinated bio‐acceptable polymers via an ATRP macroinitiator approach
Authors: Hansen Natanya M. L. , Haddleton David M. , Hvilsted Søren 
Published: October 2007

AbstractPolymers derived from bio‐acceptable poly(methyl methacrylate) (PMMA), poly(2‐methoxyethyl acrylate) (PMEA), and poly(oligo(ethylene glycol) methyl ether methacrylate) (PPEGMA) have been prepared via atom transfer radical polymerization (ATRP) utilizing an initiator prepared from a fluoroalkoxy‐terminated oligoethylene glycol. Polymerizations are controlled as seen by both linear first‐order kinetics and molecular weight evolution coupled with low polydispersities (<1.25) with respect to conversion. A range of ligands have been used depending upon the nature of the monomer: N‐(n‐propyl)‐2‐pyridyl‐methanimine with the methacrylates MMA and PEGMA and 1,1,4,7,10,10‐hexamethyltriethylene tetramine (HMTETA) with MEA. In all cases the use of the fluorinated initiator results in a lower apparent rate of propagation (kpapp) as compared with the more conventional and nonfluorinated initiator, ethyl 2‐bromoisobutyrate. The initiator generally also serves as an internal plasticizer lowering the glass transition temperature from the parent polymers. The surface characteristics of the fluoroinitiator containing polymers are altered compared with the nonfluorinated analogues. This is reflected in a significant increase in the advancing water contact angles of all fluoro‐containing polymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5770–5780, 2007
Nanopore microspheres prepared by a cationic surfmer in the miniemulsion polymerization of styrene
Authors: Cao Nana , Wang Xinbo , Song Lingyong , Zhang Zhi Cheng 
Published: October 2007

AbstractA polymerizable cationic quaternary ammonium surfactant (CQAS) based on 2‐(dimethylamino)ethyl methacrylate (DMAEMA) was successfully synthesized via quaternization reaction. The product was characterized by FTIR and 1H NMR spectroscopy, and its critical micelle concentration (CMC) was obtained by surface tension measurement. The surfmer acted well as comonomer and surfactant to stabilize monomer droplets during miniemulsion polymerization. To identify whether this system undergoes miniemulsion nucleation mechanism, surface tension, particle size, and Ndroplet/Nparticle of the system were also measured. The effect of concentration and counter‐ion of the surfmer, and pH value of the system were systematically investigated by kinetic analysis and dynamic light scattering (DLS). The resulting nanopore microspheres were observed by transmission electron micrograph (TEM) and field emission scanning electron micrograph (FESEM) and showed the nanopore morphology with reasonable stability. Another cationic surfactant cetyltrimethylammonium bromide (CTAB) was used for comparative studies. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5800–5810, 2007
Science and technology of perfluorocyclobutyl aryl ether polymers
Authors: Iacono Scott T. , Budy Stephen M. , Jin Jianyong , Smith, Dennis W. 
Published: October 2007

AbstractThis article highlights the preparation of perfluorocyclobutyl (PFCB) aryl ether polymers for a multitude of commercial technologies that are of academic and commercial global interest. In this account, the synthesis of various aryl trifluorovinyl ether (TFVE) monomers tailored for specific applications is discussed. The preparation of PFCB aryl ether polymers and their properties is then presented. Topics of PFCB aryl ether polymers and their applications include photonics, polymer light emitting diodes (PLEDs), proton exchange membranes (PEMs) for fuel cells, atomic oxygen (AO) resistant coatings, and hybrid composites. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5705–5721, 2007
Polymer nanocomposites
Authors: Krishnamoorti Ramanan , Vaia Richard A. 
Published: October 2007

AbstractPolymer nanocomposites are distinguished by the convergence of length scales corresponding to the radius of gyration of the polymer chains, a dimension of the nanoparticle and the mean distance between the nanoparticles. The consequences of this convergence on the physics of the polymer chains are considered, and some of the outstanding issues and their potential consequences on structure—property relations for polymer nanocomposites are highlighted. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3252–3256, 2007
Effects of structural imperfections on the dynamic mechanical response of main‐chain smectic elastomers
Authors: Patil Harshad P. , Hedden Ronald C. 
Published: October 2007

AbstractWe examine the influence of structural imperfections on mechanical damping in polydomain smectic main‐chain liquid crystalline elastomers (MCLCE) subjected to small strain oscillatory shear. The mechanical loss factor tan δ = G″(ω)/G′(ω) exhibits a strong maximum (tan δ ≈ 1.0) near the smectic‐isotropic (clearing) transition. “Optimal” elastomers that exhibit minimal equilibrium swelling in a good solvent are compared with highly swelling “imperfect elastomers” that contain higher concentrations of structural imperfections such as pendant chains. For the imperfect elastomers, tan δ is markedly enhanced in the isotropic state because of relaxation of pendant chains and other imperfections. However, within the smectic state, the magnitude of tan δ and its temperature dependence are similar for optimal and imperfect elastomers at ω = 1 Hz. The prominent loss peak near the clearing transition arises from segment‐level relaxations that are insensitive to the details of chain connectivity. Smectic MCLCE can be tailored for applications as vibration‐damping materials by manipulating the clearing transition temperature through the backbone structure or by deliberate introduction of structural imperfections such as pendant chains. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3267–3276, 2007
Looking inside the entanglement “tube” using molecular dynamics simulations
Authors: Larson Ronald G. 
Published: October 2007

AbstractFor 30 years, the dynamics of entangled polymers have been explained using the phenomenological “tube” model, where the “tube” represents the confining effects of surrounding chains, but the tube properties, such as its length and diameter, could only be inferred indirectly by fitting the tube model to rheological data. Now, however, molecular simulations are allowing these properties to be directly computed. The computational advances in molecular dynamics and related methods that have made this possible are here reviewed. In addition, it is discussed how new findings, such as an apparent time dependence of the tube diameter and direct observation of “hopping” of branch points along the tube, are helping to refine the tube model. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3240–3248, 2007
Modeling the accessible conformations of the intrinsically unstructured transactivation domain of p53
Authors: Lowry David F. , Stancik Amber , Shrestha Ranjay Mann , Daughdrill Gary W. 
Published: October 2007

AbstractInternuclear distances derived from paramagnetic relaxation enhancement (PRE) data were used to restrain molecular dynamics simulations of the intrinsically unstructured transactivation domain of the tumor suppressor protein, p53. About 1000 structures were simulated using ensemble averaging of replicate molecules to compensate for the inherent bias in the PRE‐derived distances. Gyration radii measurements on these structures show that the p53 transactivation domain (p53TAD) is statistically predominantly in a partially collapsed state that is unlike the open structure that is found for p53TAD bound to either the E3 ubiquitin ligase, MDM2, or the 70 kDa subunit of replication protein A, RPA70. Contact regions that potentially mediate the collapse were identified and found to consist of mostly hydrophobic residues. The identified contact regions preferentially place the MDM2 and RPA70 binding regions in close proximity. We show that our simulations thoroughly sample the available range of conformations and that a fraction of the molecules are in an open state that would be competent for binding either MDM2 or RPA70. We also show that the Stokes radius estimated from the average gyration radius of the ensemble is in good agreement with the value determined using size exclusion chromatography. Finally, the presence of a persistent loop localized to a PXP motif was identified. Serine residues flanking the PXP motif become phosphorylated in response to DNA damage, and we postulate that this will perturb the equilibrium population to more open conformations. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Identification of GATC‐ and CCGG‐recognizing Type II REases and their putative specificity‐determining positions using Scan2S—A novel motif scan algorithm with optional secondary structure constraints
Authors: Niv Masha Y. , Skrabanek Lucy , Roberts Richard J. , Scheraga Harold A. , Weinstein Harel 
Published: October 2007

AbstractRestriction endonucleases (REases) are DNA‐cleaving enzymes that have become indispensable tools in molecular biology. Type II REases are highly divergent in sequence despite their common structural core, function and, in some cases, common specificities towards DNA sequences. This makes it difficult to identify and classify them functionally based on sequence, and has hampered the efforts of specificity‐engineering. Here, we define novel REase sequence motifs, which extend beyond the PD‐(D/E)XK hallmark, and incorporate secondary structure information. The automated search using these motifs is carried out with a newly developed fast regular expression matching algorithm that accommodates long patterns with optional secondary structure constraints. Using this new tool, named Scan2S, motifs derived from REases with specificity towards GATC‐ and CGGG‐containing DNA sequences successfully identify REases of the same specificity. Notably, some of these sequences are not identified by standard sequence detection tools. The new motifs highlight potential specificity‐determining positions that do not fully overlap for the GATC‐ and the CCGG‐recognizing REases and are candidates for specificity re‐engineering. Proteins 2008. © 2007 Wiley‐Liss, Inc.
High‐throughput allelic discrimination of B and Q biotypes of the whitefly, Bemisia tabaci, using TaqMan allele‐selective PCR
Authors: Jones Christopher M , Gorman Kevin , Denholm Ian , Williamson Martin S 
Published: October 2007

AbstractBACKGROUND: B and Q biotypes of the whitefly, Bemisia tabaci (Gennadius), are generally regarded as the most significant given their global distribution and strong resistance to insecticides. Since these biotypes can coexist and differ markedly in their insecticide resistance profiles, a rapid but reliable means of discriminating between them would be a valuable complement to resistance monitoring and management programmes. Recently, PCR‐based methods have been developed to determine the biotype status of B. tabaci populations. However, these require post‐amplification procedures, which increase time and labour.RESULTS: The authors have developed an allelic discrimination real‐time PCR assay using fluorescent dye‐labelled probes to distinguish the B and Q biotypes. The assay targets a single nucleotide polymorphism (SNP) in the mitochondrial cytochrome oxidase I (mtCOI) gene. To evaluate the assay, DNA was extracted from individual whiteflies of six known biotype strains, and all scored correctly as either a B or Q biotype. As further validation, 72 individuals from field samples collected in different parts of the world were also tested by the assay. No failed reactions were observed, with all 72 samples scoring clearly as either the B or Q biotype.CONCLUSION: The development of this rapid and high‐throughput assay has important potential for routine monitoring of B and Q biotypes on ornamental plants and for the screening of B. tabaci populations in countries where these biotypes are not yet established. Copyright © 2007 Society of Chemical Industry
The physical action of three diatomaceous earths against the cuticle of the flour mite Acarus siro L. (Acari: Acaridae)
Authors: Cook Dean A , Wakefield Maureen E , Bryning Gareth P 
Published: October 2007

AbstractExperiments examined the accepted modes of action of the desiccant dust, diatomaceous earth (DE), against the flour mite, Acarus siro (L.) (Astigmata). Adult mites were exposed to three DE products for periods of 3, 18 and 72 h under conditions designed to allow partial desiccation of the mites without causing mortality. After exposure, the DE dust particles were washed off the mite bodies, and both the DE and the mites were examined for presence of cuticular hydrocarbons by gas chromatography–mass spectroscopy (GC‐MS) analysis. GC‐MS identified seven major cuticular lipids of chain length C13C26 that may have a role in the waterproofing of A. siro. After 18 h exposure, n‐tridecane and several different long‐chain fatty acid ethyl esters were detected on one of the DE products. After 72 h, n‐tridecane was detected on all three DE products. Mite samples retained after removal of the DEs were examined by microscopy. Tentative evidence was observed by conventional low‐power microscopy that might indicate uniform removal of the epicuticle. However, a detailed examination by scanning electron microscopy showed no signs of abrasion. © Crown copyright 2007. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.