bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photo‐Fries Rearrangement in Polymeric Media: An Investigation on Fully Aromatic Esters Containing the Naphthyl Chromophore
Authors: Höfler Thomas , Grießer Thomas , Gruber Mandana , Jakopic Georg , Trimmel Gregor , Kern Wolfgang 
Published: January 2008

AbstractThe present paper deals with the photo‐Fries rearrangement of fully aromatic esters in polymeric media. Low molecular weight aryl esters bearing the 1‐naphthyl chromophore were investigated with respect to their photochemical reactivity and the yield of hydroxyketones as the photo‐Fries rearrangement product. In particular, the phenyl, 4‐methylphenyl and 1‐naphthyl ester of 1‐naphthoic acid, as well as benzoic acid, 1‐naphthyl ester were dissolved in a polysiloxane matrix and exposed to 313 nm UV light. The progress of the photoreaction was assessed by quantitative FT‐IR spectroscopy. Both 1‐naphthoic acid, phenyl ester and benzoic acid, 1‐naphthyl ester underwent the photoreaction upon 313 nm irradiation. This indicates that in these fully aromatic esters, the initial CO bond scission also occurs upon selective photoexcitation of the acyl unit in the molecule. It was found that phenyl and 4‐methylphenyl esters of 1‐naphthoic acid gave the highest yields of hydroxyketone when irradiated in polymer matrix. Based upon these results, a photoreactive monomer was designed which contains naphthoic acid, phenyl ester units attached to a norbornene ring. This monomer was then polymerized by ring opening metathesis polymerization (ROMP). The polymer showed a high yield in the photo‐Fries reaction upon 313 nm illumination. Moreover, a large increase in the refractive index (Δn up to +0.043 at λ = 370 nm) was observed which makes this polymer interesting for optical applications (e.g., waveguiding and diffractive optics).magnified image
Preparation of Hybrid Nanocomposite Particles via in situ Miniemulsion Polymerization and the Sol‐Gel Process
Authors: Jia Guangwei , Xu Yongshen , Qian Jun , Xu Jiaxing 
Published: January 2008

AbstractIn this paper, the preparation of polymer/silica nanocomposite particles in a convenient one‐step process, via in situ miniemulsion polymerization and the sol‐gel technique, is described. The products were characterized using differential scanning calorimetry, transmission electron microscopy, and dynamic light scattering. Moreover, the effects of various reaction parameters, including the content of silica and the concentrations of sodium dodecyl sulfate and potassium persulfate, on the particle size and size distribution were also investigated. It is shown that polymer/silica hybrid nanocomposite particles were successfully synthesized in one step by this novel technique.magnified image
Efficient Oxygen‐Induced Molar‐Mass Control of Poly(p‐phenylene vinylenes) Synthesized via the Gilch Route
Authors: Schwalm Thorsten , Rehahn Matthias 
Published: January 2008

AbstractOxygen is shown to act as an efficient molar‐mass regulating agent in Gilch syntheses of PPV. As a scavenger, it undergoes instantaneous recombination with the initiating diradicals as soon as they appear in the system. Regular polymer formation can only start when all oxygen has been used, proceeding predominantly as chain‐growth polymerization of the p‐quinodimethane monomers. Since all radical species involved in this Gilch process are diradicals, some polyrecombination events occur in parallel. Therefore the initially formed peroxy diradicals are also incorporated into the resulting chains. Later, they break under very mild conditions, thereby causing a systematic decrease of the final molar mass of PPV.magnified image
Facile Fabrication of pH‐Responsive and Size‐Controllable Polymer Vesicles From a Commercially Available Hyperbranched Polyester
Authors: Shi Zengqian , Zhou Yongfeng , Yan Deyue 
Published: January 2008

AbstractA novel pH‐responsive polymer vesicle obtained by the aqueous self‐assembly of carboxy‐terminated hyperbranched polyesters is reported. The synthesis is very simple, just a one‐step esterification of the commercially available hydroxy‐terminated hyperbranched polyester of Boltorn Hx (x = 20, 30, 40) with succinic anhydride. The vesicle size can be controlled from 200 nm to 10 µm by simply adjusting the solution pH as well as the degrees of branching (or generation).magnified image
Polyelectrolyte Multilayer‐Mediated Growth of Gold Nanoparticle Films with Tunable Loading Density and Nanoparticle Shape
Authors: Koo Hye Young , Choi Won San , Park Jeong‐Ho , Kim Dong‐Yu 
Published: January 2008

AbstractA facile method for preparing gold nanoparticle (AuNP) films with a high loading density based on the seed‐mediated growth of AuNPs on a polyelectrolyte multilayer (PEM) is reported. Use of PEMs as a base layer for gold seed adsorption confers controllability on the loading density of the AuNP film and size of the resulting AuNPs. In addition, the shape of the final AuNPs could be varied by adapting various species of polyelectrolytes. The optical response of the AuNP films is stable, because of the relatively uniform distribution of the AuNPs over a large area. The AuNP film has been used as a substrate for surface‐enhanced Raman scattering (SERS), and it shows stable and reproducible enhancement in the range from 105 to 107 depending on the fabrication condition.magnified image
Fabrication of Fullerene‐Containing Hybrid Vesicles via Supramolecular Self‐Assembly of a Well‐Defined Amphiphilic Block Copolymer Incorporated with a Single C60 Moiety at the Diblock Junction Point
Authors: Wang Xiaofeng , Zhang Yanfeng , Zhu Zhiyuan , Liu Shiyong 
Published: January 2008

AbstractA well‐defined amphiphilic block copolymer bearing a reactive azide group at the interface of two blocks, poly(ethylene oxide)(‐azido)‐block‐polystyrene (PEO(‐N3)‐b‐PS), has been successfully synthesized via a combination of end group transformation and atom transfer radical polymerization (ATRP). The subsequent [3 + 2] cycloaddition reaction between PEO(‐N3)‐b‐PS and C60 led to the facile preparation of PEO(‐C60)‐b‐PS, in which a single C60 moiety was located at the diblock junction point. Fullerene‐containing hybrid vesicles were then fabricated for the first time via the supramolecular self‐assembly of PEO45(‐C60)‐b‐PS380 in aqueous solution using 1,4‐dioxane as the cosolvent. The current example augurs well for tunable spatial ordering of desired moieties (fullerene or other functional nanoparticles) by employing block copolymers as self‐organizing templates.magnified image
A mesenchymal perspective of müllerian duct differentiation and regression in Amhr2‐lacZ mice
Authors: Arango Nelson A. , Kobayashi Akio , Wang Ying , Jamin Soazik P. , Lee Hu‐Hui , Orvis Grant D. , Behringer Richard R. 
Published: January 2008

AbstractThe Müllerian ducts give rise to the female reproductive tract, including the Fallopian tubes, uterus, cervix, and anterior vagina. In male embryos, the Müllerian ducts regress, preventing the formation of female organs. We introduced the bacterial lacZ gene, encoding β‐galactosidase (β‐gal), into the AMHR‐II locus (Amhr2) by gene targeting in mouse embryonic stem (ES) cells to mark Müllerian duct differentiation and regression. We show that Amhr2‐lacZ heterozygotes express β‐gal activity in an Amhr2‐specific pattern. In the gonads, β‐gal activity was detected in Sertoli cells of the testes from 2 weeks after birth, and fetal ovaries and granulosa cells of the adult ovary. β‐gal activity was first detected in the rostral mesenchyme of the Müllerian ducts at 12.5 days post coitus (dpc) in both sexes but soon thereafter expression was found along the entire length of the Müllerian ducts with higher levels initially found in males. In females, β‐gal activity was restricted to one side of the ductal mesoepithelium, whereas in males β‐gal expression encircled the duct. β‐gal activity was also detected in the coelomic epithelium at 13.5 and 14.5 dpc. In male embryos, mesenchymal β‐gal activity permitted the visualization of the temporal and spatial pattern of Müllerian duct regression. This pattern was similar to that observed using a Müllerian duct mesoepithelium lacZ reporter, indicating a coordinated loss of Müllerian duct mesoepithelium and Amhr2‐expressing mesenchyme. Mol. Reprod. Dev. 75: 1154–1162, 2008. © 2008 Wiley‐Liss, Inc.
Differential regulation of the Oct‐3/4 gene in cell culture model systems that parallel different stages of mammalian development
Authors: Mallanna Sunil Kumar , Boer Brian , Desler Michelle , Rizzino Angie 
Published: January 2008

AbstractOct‐3/4 is an essential transcription factor that regulates stem cell fate during embryogenesis. Previous reports have shown that the Oct‐3/4 gene utilizes different enhancers to regulate its expression as development proceeds. However, the cis‐elements contributing to the differential activity of these enhancers require further study. Here, we investigated the function of the HMG/POU cassette and LRH‐1 site present in the distal enhancer (DE) and the proximal enhancer, respectively. F9 and P19 EC cells were the focus of this study because their differential utilization of Oct‐3/4 enhancers parallels the use of these enhancers during different stages of development. We determined that the LRH‐1 site functions as a positive and a negative cis‐regulatory element in P19 and F9 EC cells, respectively. Furthermore, we determined that the HMG/POU cassette in the DE strongly activates the Oct‐3/4 promoter in F9 cells, but is a much weaker positive regulatory element in P19 cells. Given that HMG/POU cassettes play key roles in the regulation of at least seven essential genes, the Oct‐3/4 HMG/POU cassette was examined more closely by focusing on Sox2, which can bind to HMG/POU cassettes. Although chromatin immunoprecipitation demonstrated that Sox2 binds to the Oct‐3/4 gene equally well in both EC cell lines, tethering Sox2 to the region of the HMG/POU cassette only activated the Oct‐3/4 promoter in F9 EC cells. These and other findings suggest that the differential activity of the HMG/POU cassette of the Oct‐3/4 gene in EC cells is due to differential action of Sox2 and its associated co‐factors. Mol. Reprod. Dev. 75: 1247–1257, 2008. © 2008 Wiley‐Liss, Inc.
Dye removal by a novel hydrogel‐clay nanocomposite with enhanced swelling properties
Authors: Kaşgöz Hasine , Durmus Ali 
Published: January 2008

AbstractAcrylamide (AAm)‐2‐acrylamide‐2‐methylpropanesulfonic acid sodium salt (AMPSNa) hydrogel and AAm‐AMPSNa/clay hydrogel nanocomposite having 10 w% clay was prepared by in situ copolymerization in aqueous solution in the presence of a crosslinking agent (N,N′‐methylenebisacrylamide (NMBA)). Swelling properties and kinetics of the hydrogel samples were investigated in water and aqueous solutions of the Safranine‐T (ST) and Brilliant Cresyl Blue (BCB) dyes. The swelling and diffusion parameters were also calculated in water and dye solutions. It was observed that the AAm‐AMPSNa/clay hydrogel nanocomposite exhibits improved swelling capacity compared with the AAm‐AMPSNa hydrogel. It was also found that the diffusion mechanisms show non‐Fickian character. Adsorption properties of the hydrogel samples in the aqueous solution of ST and BCB dyes were also investigated. Clay incorporation into the hydrogel structure increased not only the adsorption capacity but also the adsorption rate. Adsorption capacity values of the hydrogel nanocomposite were found to be 484.2 and 494.2 mg g−1 for the ST and BCB dyes, respectively. It was seen that the adsorption of dyes by the hydrogel nanocomposite completed in 10 min while the AAm‐AMPSNa hydrogel adsorbed dyes approximately in 90 min. Adsorption data of the samples were modelled by the pseudo‐first‐order and pseudo‐second‐order kinetic equations in order to investigate dye adsorption mechanism. It was found that the adsorption kinetics of hydrogel nanocomposite followed a pseudo‐second‐order model. Equilibrium isotherms were analyzed using the Langmuir and Freundlich isotherms. It was seen that the Langmuir model fits the adsorption data better than the Freundlich model. Copyright © 2008 John Wiley & Sons, Ltd.
Treatment of B‐cell lymphoma with LMB modified protocols in Africa—report of the French‐African Pediatric Oncology Group (GFAOP)
Authors: Harif Mhamed , Barsaoui Sihem , Benchekroun Said , Bouhas Rachid , Doumbé Pierre , Khattab Mohammed , Ladjaj Yasmina , Moreira Claude , Msefer‐Alaoui Fouzia , Patte Catherine , Rakotonirina Gervais , Raphael Martine , Raquin Marie‐Anne , Lemerle Jean 
Published: January 2008

AbstractBackgroundThe French African Paediatric Oncology Group (GFAOP) was set up in October 2000 to improve the quality of care of children with cancer in Africa. Eight pediatric oncology units from Algeria, Cameroon, Madagascar, Morocco, Tunisia, and Senegal have been involved.MethodsPatients less than 18 years with cytology or histology proven B‐cell non‐Hodgkin lymphoma were included. Two LMB89 modified regimens were proposed (MAT and GFA).ResultsFrom April 2001 to April 2004, 343 cases were registered. Thirty seven patients were excluded. Thirteen patients were stage I, 26 stage II, 209 stage III and 50 stage IV including 8 L3 acute lymphoblastic leukemia (ALL3) cases. Three year OS of the whole population of patients is 61%. In GFA group 36 months OS is 63.6% in stages I/II, 51.6% in stage III and 35.8% in stage IV. In MAT group, the OS is 84.4% in stages I/II, 76.2% in stage III and 55.6% in stage IV. Seventy one patients died during treatment, 32 at pre‐induction phase, 27 at induction and 12 at consolidation. Treatment related mortality decreased during the 3‐year inclusion period (first year: 25.7%, second year: 19.1%, third year: 11.6%). The improvement of supportive care translated into an increase of the overall survival rates from 54% in the first year to 73% in the third year.ConclusionThese data demonstrate the feasibility of prospective multicentric studies in Africa. An improvement of quality of care has been noticed during the 3 first years. Pediatr Blood Cancer 2008;50:1138–1142. © 2008 Wiley‐Liss, Inc.
Neural cell adhesion molecule (NCAM) isoform expression is associated with neuroblastoma differentiation status
Authors: Winter Cynthia , Pawel Bruce , Seiser Eric , Zhao Huaqing , Raabe Eric , Wang Qun , Judkins Alex R. , Attiyeh Edward , Maris John M. 
Published: January 2008

AbstractBackgroundNCAM is a member of the immunoglobulin superfamily of cell adhesion molecules. While highly expressed on neuroblastoma cells, the relative contribution of the three major NCAM isoforms (120, 140, and 180 kDa) to neuroblastoma biology has not been investigated.MethodsNCAM protein expression was measured in a neuroblastic tumor tissue microarray (N = 185) by immunohistochemistry. Relative expression of NCAM mRNA isoforms was measured in a panel of 24 human neuroblastomas and compared to fetal and adult human brain using real‐time quantitative PCR and Western blot analysis. Associations with clinical and tumor biological co‐variates were performed.ResultsNCAM protein was detected on all neuroblastic tumors and was highly expressed in all but 7/167 cases. The mRNA species predicted to encode the 120 kDa protein species was the most abundant isoform in adult brain, ganglioneuromas and ganglioneuroblastomas (P = 0.0007), but the mRNA predicted to encode the 180 kDa species was predominant in neuroblastomas (P = 0.043). Microdissected ganglion and neuroblast cells from human primary tumors confirmed these findings.ConclusionGanglioneuromas and ganglioneuroblastomas express the adhesive 120 kDa NCAM isoform, while neuroblastomas preferentially express the 180 kDa isoform classically involved in cell motility. These data suggest a mechanism for the enhanced metastatic potential of undifferentiated neuroblastomas. Pediatr Blood Cancer 2008;51:10–16. © 2008 Wiley‐Liss, Inc.
Deep venous thrombosis in adolescents due to anatomic causes
Authors: Bruins Benjamin , Masterson Margaret , Drachtman Richard A. , Michaels Lisa A. 
Published: January 2008

AbstractAberrant or anomalous anatomy is an under appreciated risk for venous thromboembolic events (VTE). Five adolescents with VTE and predisposing anatomic abnormalities are presented. In three cases, knowledge of the underlying anatomic abnormalities resulted in changes in treatment and management. In two other cases, failure to consider or correct the underlying defect resulted in recurrent thrombosis or post‐thrombotic complications. Few case reports are found in the pediatric literature, but a MEDLINE search across all age groups suggests these anomalies are frequently found when appropriate radiological imaging is obtained. Pediatr Blood Cancer 2008;51:125–128. © 2008 Wiley‐Liss, Inc.
Statistical analysis of the mechanical properties of natural fibers and their composite materials. II. Composite materials
Authors: Peponi Laura , Biagiotti Jerico , Kenny Josè M. , Mondragòn Iñaki 
Published: January 2008

AbstractIn this study, the tensile behavior of different natural fiber reinforced composite materials were analyzed. The statistical analysis used to study the natural fibers in the first article, has been extended to analyze the behavior of PP‐matrix composites, combining the probability density function estimation of fiber properties with the Halpin‐Tsai equation. In this case, the advanced statistical approach overestimates the mechanical properties of the composites, probably because of the poor matrix‐fiber adhesion between polypropylene and natural fibers in the real system. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Functional polyethylene composites prepared via polymerization of ethylene with opal‐immobilized zirconocene complex
Authors: Xu Hao , Wang Xinwei , Guo Cun‐Yue , Li Qingshan 
Published: January 2008

AbstractAn opal‐supported zirconocene complex (OC) was prepared and employed to prepare functional polyethylene composite for the first time through in situ polymerization of ethylene. The formation mechanism of anion relating to opal was explained and the values of anions released from pristine opal and that contained in the as‐fabricated polyethylene composites were detected. The OC exhibited high catalytic activities in ethylene polymerization with methylaluminoxane (MAO) the cocatalyst. In addition to higher viscosity‐average molecular weights (Mη), experimental results also showed that the resulting polyethylene composites possessed improved anion‐releasing capacity in comparison with pristine opal in addition to increased tensile strength, Young's modulus, and onset decomposition temperature (Tonset) relative to neat polyethylene due to highly uniform dispersion of opal in polyethylene matrix. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Statistical analysis of the mechanical properties of natural fibers and their composite materials. I. Natural fibers
Authors: Peponi Laura , Biagiotti Jerico , Torre Luigi , Kenny Josè M. , Mondragòn Iñaki 
Published: January 2008

AbstractIn this study, we extended a statistical approach to develop a comparative study on the behavior of different natural fibers such as flax, jute, abaca, and sisal. In particular, the dimensional characterization and mechanical properties of natural fibers were considered. The wide dispersion of fiber properties, which is a well‐known characteristic of natural systems, has been described here by means of a new advanced statistical approach based on neural network algorithms that can provide a more accurate prediction of the behavior of natural fibers. The new statistical model was developed to interpolate the experimental data, using algorithms based on neural networks. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Pattern of adverse drug reactions to anti‐epileptic drugs: a cross‐sectional one‐year survey at a tertiary care hospital
Authors: S Roopa B. , Narayan Sujatha S. , Sharma G. R. K , Rodrigues Rashmi J , Kulkarni Chanda 
Published: January 2008

AbstractPurposeTo investigate pattern and extent of adverse drug reactions (ADRs) associated with AEDs and to identify safer options for treatment of epilepsy.MethodStudy was a retrospective, cross‐sectional survey. Data from patients with epilepsy at the out‐patient and in‐patient of Neurology Department was collected in a specially designed proforma. Causality and severity of ADRs was categorized as per WHO guidelines.ResultsAmong 788 patients with epilepsy, 80 (10.27%) had ADRs. ADRs with AED monotherapy were 9.18% and with polytherapy were 11.56%. ADRs with conventional and newer AED monotherapy was 10.24% and 6.84%, respectively, and were maximum with phenytoin and clobazam (14.28% and 12.5%). ADRs were mild in 4.16%, moderate in 70.83% and severe in 25% patients. Causality was probable in 65.62%, possible in 13.54% and definite in 20.83%. Patients (15/80) were hospitalized due to ADRs. Age and gender distribution showed statistically significant difference in occurrence of ADRs (p < 0.05). Chi‐square test for poly versus monotherapy and conventional versus newer AEDs did not show any significant difference.ConclusionsStudy showed maximum ADRs with AED polytherapy with no significant difference in frequency and severity of ADRs between conventional versus newer AEDs. This finding needs further investigation in larger number of patients to identify safer treatment options for epilepsy. Copyright © 2008 John Wiley & Sons, Ltd.
Model‐based melt flow virtual sensors for filling process of injection molding
Authors: Lin Yu‐Wei , Cheng J.‐W. John 
Published: January 2008

AbstractBased on the model‐based virtual sensing approach, previously proposed by the authors, two melt flow virtual sensors are developed. The virtual sensors estimate the melt front position during the filling process by using easily obtained machine variables, specifically, the injection hydraulic pressure and the screw position and nozzle pressure. Both virtual sensors were theoretically analyzed and experimentally evaluated on a commercial injection molding machine. The theoretical analysis provides step‐by‐step design guidelines for the virtual sensors. Performance evaluation with a twin thin‐plate mold validates the feasibility of the proposed model‐based melt‐flow virtual sensors. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Modeling particle inflation from poly(amic acid) powdered precursors. III. Experimental determination of kinetic parameters
Authors: Cano Camilo I. , Clark Meaghan L. , Kyu Thein , Pipes R. Byron 
Published: January 2008

AbstractSeveral concurrent phenomena occur during the thermal inflation of poly(amic acid) precursor particles leading to polyimide foams as part of the solid‐state powder foaming process. The precursor experiences bubble growth from within while volatiles desorb and the polymer itself increases its molecular weight and changes its backbone structure. These changes affect the transport properties of the material by modifying significantly the effective glass transition temperature, Tg. By studying the chemical transformations that take place during the inflation process (amidation and imidization reactions), a complete understanding of the material's molecular changes can be obtained and corresponding property changes can be followed. This article is the third of a series where the inflation of precursor materials for polyimide foams has been studied. The two previous articles in the series present numerical models that simulate the inflation process from first principles. In this article, the authors discuss the experimental and analytical methodologies employed to accurately characterize and incorporate the changes in material and transport properties as a function of the glass transition temperature. POLYM. ENG SCI., 2008. © 2008 Society of Plastics Engineers