bluuebunny/crossref_metadata_2025_split huggingface dataset:
First indication of Storegga tsunami deposits from East Greenland
Authors: Wagner Bernd , Bennike Ole , Klug Martin , Cremer Holger 
Published: December 2006

AbstractA 2.73 m long sediment sequence from Loon Lake, located at 18 m a.s.l. on outer Geographical Society Ø, East Greenland, was investigated for its chronology and changes in physical and biogeochemical properties, macrofossils, and grain‐size distribution. The predominance of marine fossils throughout the sequence, dated by 14C AMS to between 8630 and 7535 cal. yr BP, shows that the Loon Lake at that time was a marine basin, which according to existing sea‐level curves was about 15–35 m deep. The sequence mainly consists of fine grained homogeneous sediments, which are interrupted by a 0.72 m thick sandy horizon with erosive basis and distinct fluctuations in the grain‐size distribution and in the physical and biogeochemical properties. According to the radiocarbon dates, this sandy horizon was deposited after 8500–8300 cal. yr BP and is interpreted as originating from the Storegga tsunami. The record from Loon Lake provides the first indication of Storegga tsunami deposits from East Greenland. Copyright © 2006 John Wiley & Sons, Ltd.
Pulse shaping control of alignment dynamics in N2
Authors: de Nalda R. , Horn C. , Wollenhaupt M. , Krug M. , Bañares L. , Baumert T. 
Published: December 2006

AbstractControl on the alignment transients of impulsively aligned ensembles of N2 molecules has been demonstrated by the use of laser pulses shaped by a spatial light modulator. An alignment experiment has been inserted in the feedback loop of an evolutionary algorithm that found optimum pulse shapes for a set of criteria. Optimum pulse shapes for the maximization of total alignment and for the control of certain aspects of the revival structures are given. The physical mechanisms responsible for the control are analysed with the help of single‐parameter control schemes and numerical simulations, which allowed us to explore the low‐temperature region. This approach sheds light on the role played by different control mechanisms for the alignment dynamics of a molecular ensemble. Copyright © 2006 John Wiley & Sons, Ltd.
Uniform convergence for elliptic problems on varying domains
Authors: Arendt Wolfgang , Daners Daniel 
Published: December 2006

AbstractLet Ω ⊂ ℝNbe (Wiener) regular. Forλ> 0 andf∈L∞(ℝN) there is a unique bounded, continuous functionu: ℝN→ ℝ solvingλu– Ωu=f in 𝔻(Ω)′,  u= 0 on ℝN\ Ω.Given open sets Ωnwe introduce the notion ofregular convergenceof Ωnto Ω asn→ ∞. It implies that the solutionsunof (P) converge (locally) uniformly touon ℝN. WhereasL2‐convergence has been treated in the literature, our criteria for uniform convergence are new. The notion of regular convergence is very general. For instance the sequence of open sets obtained by cutting into a ball converges regularly. Other examples show that uniform convergence is possible even if the measure of Ωn\ Ω stays larger than a positive constant for alln∈ ℕ. Applications to spectral theory, parabolic equations and nonlinear equations are given. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the complex moment problem
Authors: Berezansky Yurij M. , Dudkin Mykola E. 
Published: December 2006

AbstractThe article is devoted to the solution of the infinite‐dimensional variant of the complex moment problem, and to the uniqueness of the solution. The main approach is illustrated for the best explanation on the one‐dimensional case. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐differentiability points of Cantor functions
Authors: Li Wenxia 
Published: December 2006

AbstractLet the Cantor set C in ℝ be defined by C = ∪r j =0 hj (C) with a disjoint union, where the hj 's are similitude mappings with ratios 0 < aj < 1. Let μ be the self‐similar Borel probability measure on C corresponding to the probability vector (p 0, p 1, …, pr). Let S be the set of points at which the probability distribution function F (x) of μ has no derivative, finite or infinite. For the case where pi > ai we determine the packing and box dimensions of S and give an approach to calculate the Hausdorff dimension of S. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterizations of weighted Besov spaces
Authors: Pradolini G. , Viviani B. 
Published: December 2006

AbstractWe define a class of weighted Besov spaces and we obtain a characterization of this class by means of an appropriate class of weighted Lipschitz ϕ spaces. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interior regularity criterion via pressure on weak solutions to the Navier–Stokes equations
Authors: Suzuki Tomoyuki 
Published: December 2006

AbstractConsider the nonstationary Navier–Stokes equations in Ω × (0, T), where Ω is a bounded domain in ℝ3. We prove interior regularity for suitable weak solutions under some condition on the pressure in the class of scaling invariance. The notion of suitable weak solutions makes it possible to obtain better information around the singularities. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fundamental Aspects of Measuring Copolymerization Reactivity Ratios Using Real‐Time FTIR Monitoring
Authors: Puskas Judit E. , McAuley Kimberley B. , Chan S. W. Polly 
Published: December 2006

AbstractReal‐time FTIR is a powerful tool to obtain copolymerization reactivity ratios because it allows simultaneous monitoring of individual monomer consumption rates. Based on the Mayo‐Lewis equation we showed that in reactivity ratios can be defined as the ratios of apparent rate constants of monomer consumption. The validity and limitations on this new method are discussed in the isobutylene‐isoprene and isobutylene‐styrene carbocationic copolymerization systems.
Kinetic Modeling of Non‐Linear Polymerization
Authors: Costa Mário Rui P. F. N. , Dias Rolando C. S. 
Published: December 2006

AbstractRecent developments of a method based upon population balances of generating functions of polymer chain length distributions (CLD) are presented. The calculation of the CLD and how to take into account chain length dependent reactivity are discussed. Prediction of polymer properties is also possible but only easily done for the average molecular radius of gyration; some results are presented for a radical polymerization including transfer to polymer and propagation with terminal double bonds.
Monte Carlo Simulation of Ethylene Copolymers: A Look into the Monomer Sequence Distribution
Authors: Al‐Saleh Mohammad A. , Simon Leonardo C. 
Published: December 2006

AbstractA comprehensive mathematical model was developed using Monte Carlo simulation to describe the mechanism of ethylene and α‐olefin copolymerization. The model studies the polymerization mechanism using coordination catalysts and is able to predict molecular weight and detailed chemical composition distributions. This work is considered to be a useful tool that enables us to understand and described the monomer sequence distribution as a function of chain length in semi‐batch polymerization reactors.
Population Balance Model for Emulsion Polymerisation Under Pseudo‐Bulk Conditions: Combined Particle Size Distribution and Molecular Weight Distribution
Authors: Sweetman Stephen J. , Immanuel Charles D. , Malik Tahir , Emmett Simon , Williams Neal 
Published: December 2006

AbstractA comprehensive model for emulsion polymerisation is presented, accounting for particle size distribution (PSD) and molecular weight distribution (MWD). The PSD information is incorporated through a population balance framework. A mechanistic formulation is adopted in modelling the average number of radicals/particle under pseudo‐bulk compartmentalisation conditions. The method of moments is adopted to simplify the MWD equations over each discrete size class. The impact of the pseudo‐bulk assumption on the PSD and MWD results is assessed. An identification of potential manipulated variables for control of PSD and MWD is done through sensitivity analysis.
Estimation of Free Radical Polymerization Rate Coefficients Using Computational Chemistry
Authors: Bebe Siziwe , Yu Xinrui , Hutchinson Robin A. , Broadbelt Linda J. 
Published: December 2006

AbstractThis study explores the application of computational chemistry to estimate free radical polymerization rate coefficients. The Evans‐Polanyi relationship is combined with computed heats of polymerization to estimate copolymerization reactivity ratios for many vinyl monomer pairs, focusing on acrylates, methacrylates and styrene, with accuracy assessed by comparison to experimental values. The effect of different optimization approaches on the values of thermodynamic properties is explored, and it is concluded that a combination of conventional optimization and relaxed potential energy scans was most effective at identifying global minima. The difference between thermodynamic properties calculated using the harmonic oscillator treatment and a hindered rotor model is evaluated for methyl methacrylate polymerization.
Synthesis of Poly(Vinyl Alcohol) and/or Poly(Vinyl Acetate) Particles with Spherical Morphology and Core‐Shell Structure and its Use in Vascular Embolization
Authors: Peixoto Luciana S. , Silva Fabricio M. , Niemeyer Mariana A. L. , Espinosa Gaudencio , Melo Príamo A. , Nele Márcio , Pinto José Carlos 
Published: December 2006

AbstractPoly(vinyl alcohol), PVA, is the most frequently used material in embolization of tumors, aneurisms and arteriovenous malformations due to its low toxicity, good biocompatibility and desirable physical properties. It is well known that PVA particles cannot be prepared by direct polymerization of vinyl alcohol. Its synthesis is typically performed by the suspension polymerization of vinyl acetate to produce poly(vinyl acetate), PVAc, followed by the saponification of the PVAc particles. This work shows that, using the suspension polymerization technique, it is possible to obtain spherical particles with a core‐shell structure of PVA/PVAc with regular morphology, instead of particles with irregular shapes and sizes, as usually found in many commercial embolization products. Therefore, this work presents the production of PVA/PVAc spherical particles that can be used to occlude blood vessels, eliminating the disadvantages of commercial PVA. In vivo clinical tests with white “New Zealand” rabbits undergoing kidney inflammation reaction have shown that these spherical particles are much more efficient for vascular embolization.
An Integrated Model‐Based Analysis of Polymer Chemistry and Polymerisation Reactors
Authors: Immanuel Charles D. , Steinke Joachim H. G. , Higgins Julia S. 
Published: December 2006

AbstractIn this paper, a simple demonstration is presented on the analysis of the combined effect of polymer chemistry and the polymerisation reactor on the polymer properties. The model would ideally account for the raw material and end‐product characteristics and properties on the one hand; the polymerisation kinetics and reaction engineering on the other hand. This system‐wide model‐driven approach enables the interlinking of the widely disparate facets of polymer science and engineering, and thereby provides a tool for rapid and efficient identification and scale‐up of new polymeric materials that would be exploited in future studies. The ideas are demonstrated with regard to a hyper‐branched polymerisation chemistry.
Formation of Nanostructures in Multi Component Systems Based on Organic Polymer and Coordination Metal Compound
Authors: Kozak Nataly , Nizelskii Yurij , Mnikh Nadya , Shtompel Vladimir , Grischuk Oleg 
Published: December 2006

AbstractStructuring of polyurethane (PU) networks is analyzed under influence of transition metal coordination compounds: mono‐ionic β‐diketonates and polyheteronuclear metal‐organic complexes. Formed in situ nanostructures both organic and inorganic were found in organic polymer modified with coordination metal compound. Influence of coordination junction point spatial symmetry and content of metal ion in modifier on structure and dielectric characteristics of modified PUs is analyzed using X‐ray, EPR, SEM and transmission optical microscopy, DRS and DSC methods.
Synthesis of Bimodal PVC Latexes by Emulsion Polymerization: An Experimental and Modeling Study
Authors: Vale Hugo M. , McKenna Timothy F. 
Published: December 2006

AbstractThe onset and extent of secondary particle formation in the seeded emulsion polymerization of vinyl chloride were investigated by performing a series of seeded polymerizations at different concentrations of seed latex and surfactant. It was found that, in general, both the onset and the extent of secondary particle formation are determined not only by the rate of homogeneous nucleation, but also by the rates of particle coagulation. A comparison of methods to compute the evolution of the particle size distribution in vinyl chloride emulsion polymerization was also carried out. For growth processes, the widely‐used pseudo‐bulk model gives correct answers. For processes involving particle formation, on the other hand, this model cannot be used because it neglects, among others, the effects of nucleation and coagulation on the radical number distribution. To surmount this problem, we propose to use the zero‐one‐two model, for which the full population balance equations are given here.
Polymerization Compounding on the Surface of Zirconia Nanoparticles
Authors: Esmaeili Babak , Chaouki Jamal , Dubois Charles 
Published: December 2006

AbstractZirconia nanoparticles were encapsulated by polyethylene via a polymerization compounding method using a Ziegler‐Natta catalyst. The chemical reaction was carried out in an organic solvent under moderate pressure of ethylene monomer. Transmission electron microscopy (TEM) indicated the presence of a thin layer of polymer, about 6 nm, uniformly applied around the particles. However, the thickness of coating layer can be controlled as a function of time and operating conditions of the process. The morphology study using scanning electron microscopy (SEM) as well as TEM revealed that although the nanoparticles seem to be coated individually, some agglomerates, encapsulated by a polymer film, could be observed. The grafting of the catalyst to the original surface of particles was further confirmed by X‐ray photoelectron spectroscopy (XPS).
A Single‐Gallery Model for the In Situ Production of Polyethylene‐Clay Nanocomposites
Authors: Maneshi Abolfazl , Soares João B. P. , Simon Leonardo C. 
Published: December 2006

AbstractPolyolefin‐clay nanocomposites are finding many new applications because of their improved properties, such as high modulus, elevated scratch resistance and low gas permeability. Currently, these composites are produced by melt blending organically modified clay with polyolefins. The most challenging step in this process is the intercalation and exfoliation of the clay to produce a homogenously dispersed phase at the nanoscale. A promising alternative to melt blending is in‐situ polymerization, where the polymer is produced between the clay layers in the polymerization reactor. In‐situ polymerization of olefins with metallocene catalysts supported on clay can produce nanocomposites using conventional polymerization reactors, provided that the clay can be used as a support for the olefin polymerization catalyst. In this approach, the clay fulfills the functions of catalyst support and dispersed phase in the final nanocomposite. In this work, a mathematical model describing particle growth during in‐situ polymerization of ethylene with a metallocene catalyst supported on clay will be discussed. The model expands the approach of the multi‐grain model used in heterogeneous olefin polymerization to account for the layered structure of clays.
Modulation of UVB‐induced and basal cyclooxygenase‐2 (COX‐2) expression by apigenin in mouse keratinocytes: Role of USF transcription factors
Authors: Van Dross Rukiyah T. , Hong Xiaoman , Essengue Suzanne , Fischer Susan M. , Pelling Jill C. 
Published: December 2006

AbstractApigenin is a bioflavonoid with chemopreventive activity against UV‐ or chemically‐induced mouse skin tumors. To further explore the mechanism of apigenin's chemopreventive activity, we determined whether apigenin inhibited UVB‐mediated induction of cyclooxygenase‐2 (COX‐2) expression in mouse and human keratinocytes. Apigenin suppressed the UVB‐induced increase in COX‐2 protein and mRNA in mouse and human keratinocyte cell lines. UVB radiation of keratinocytes transfected with a mouse COX‐2 promoter/luciferase reporter plasmid resulted in a threefold increase in transcription from the promoter, and apigenin inhibited the UV‐induced promoter activity at doses of 5–50 µM. Transient transfections with COX‐2 promoter deletion constructs and COX‐2 promoter constructs containing mutations in specific enhancer elements indicated that the effects of UVB required intact Ebox and ATF/CRE response elements. Electrophoretic mobility shift assays with supershifting antibodies were used to identify USF‐1, USF‐2, and CREB as proteins binding to the ATF/CRE‐Ebox responsive element of the COX‐2 promoter. Keratinocytes co‐transfected with the COX‐2 luciferase reporter and a USF‐2 expression vector, alone or in combination with a USF‐1 expression vector, exhibited enhanced promoter activity in both UVB‐irradiated and nonirradiated cultures. However, COX‐2 promoter activity was inhibited in keratinocytes co‐transfected with USF‐1 alone. Finally, we present data showing that the suppressive effect of apigenin on COX‐2 expression could be reversed by co‐expression of USF‐1 and USF‐2. These results suggest that one pathway by which apigenin inhibits COX‐2 expression is through modulation of USF transcriptional activity. © 2006 Wiley‐Liss, Inc.
Bone marrow mononuclear cells stimulate angiogenesis when transplanted into surgically induced fibrocollagenous tunnels: Results from a canine ischemic hindlimb model
Authors: Padilla Luis , Krötzsch Edgar , De La Garza Anabel S. , Figueroa Siegfried , Rodriguez‐Trejo Juan , Ávila Gerardo , Schalch Paul , Escotto Ignacio , Glennie Germán , Villegas Fernando , Di Silvio Mauricio 
Published: December 2006

AbstractProgenitor cell transplantation has been considered as a potential angiogenesis therapy for the ischemic hindlimb. In this work we performed an ischemic hindlimb model in dogs. We ligated the middle sacra and the external right iliac arteries. After 7 days, the femoral artery was ligated and removed, and three Silastic® tubes were inserted into the gracilis muscle to create fibrocollagenous tunnels. After Silastic® implantation, we administered saline or granulocyte colony stimulating factor (G‐CSF) subcutaneously daily during 5 days. Fourteen days after device positioning we transplanted bone marrow mononuclear cells (BMMC) into the tunnels previously formed by Silastic® tube reaction. Twenty‐eight days later, contrasted angiographies were performed and angiographic scores were calculated. Also, vessels and endothelial cells and proliferating cells were identified by immunochemistry of muscle sections. Results demonstrated that BMMC transplantation enriched by G‐CSF administration significantly stimulates angiogenesis in the ischemic hindlimb, and more than BMMC transplantation alone. Transplantation of progenitor cells in an appropriate extracellular matrix is a potential therapy for hindlimb ischemia. © 2006 Wiley‐Liss, Inc. Microsurgery, 2007.
Beneficial effects of dithiothreitol on relative levels of glutathione S‐transferase activity and thiols in oocytes, and cell number, DNA fragmentation and allocation at the blastocyst stage in the mouse
Authors: Rausell Francisco , Pertusa José F. , Gómez‐Piquer Vanessa , Hermenegildo Carlos , García‐Pérez Miguel A. , Cano Antonio , Tarín Juan J. 
Published: December 2006

AbstractWe analyzed the effect of in vitro aging of mouse oocytes in the presence of dithiothreitol (DTT) on relative levels of glutathione S‐transferase (GST) activity and thiols in oocytes, and cell number, DNA fragmentation and cellular allocation to the inner cell mass (ICM) and trophectoderm (TE) lineage at the blastocyst stage. Ovulated oocytes from gonadotropin primed hybrid female mice of 6–8 weeks of age were aged in vitro in the presence of 0, 5, 50, or 500 µM DTT for 6 hr prior to insemination. Relative levels of GST activity and thiols in oocytes were determined by confocal laser scanning microscopy, DNA fragmentation using a single‐step TUNEL method, and cell allocation to the ICM and TE lineage by blastocyst staining with propidium iodide and Hoechst 33258. Non‐aged oocytes exhibited higher relative levels of GST activity and thiols when compared to oocytes aged in the presence of 0, 5, and 50 µM DTT. Day 5 blastocysts from the 5, 50, and 500 µM DTT groups exhibited higher total number of cells, number of ICM cells, and ICM/TE ratio, but lower percentage of number of nuclei with DNA fragmentation/number of ICM cells than blastocyst from the 0 µM DTT group. These data show that DTT counteracts the negative effects of a post‐ovulatory aging of mouse oocytes in vitro on relative levels of GST activity and thiols in oocytes, and percentage of number of nuclei with DNA fragmentation/number of ICM cells, total number of cells, number of ICM cells and ICM/TE ratio in Day 5 blastocysts. Mol. Reprod. Dev. 74: 860–869, 2007. © 2006 Wiley‐Liss, Inc.
Impact of cryopreservation and reactive oxygen species on DNA integrity, lipid peroxidation, and functional parameters in ram sperm
Authors: Peris Soliman I. , Bilodeau Jean‐François , Dufour Maurice , Bailey Janice L. 
Published: December 2006

AbstractAssisted reproduction using frozen‐thawed semen has practical advantages, although cryopreservation is detrimental to sperm fertility in most mammals. We examined the influence of cryopreservation and reactive oxygen species (ROS) on ram sperm DNA stability (using SCSA), lipid peroxidation (LPO), chlortetracycline fluorescence (CTC) patterns, motility and viability. In Experiment 1, DNA integrity, LPO, CTC, motility and viability tests were performed on fresh and cryopreserved sperm after 0, 6, and 24 hr in synthetic oviductal fluid (SOF). In Experiment 2, fresh sperm were incubated in serum‐free SOF (SOF‐S; 1, 4, and 24 hr) with 0, 50, 150, or 300 µM H2O2 then assayed. Cryopreservation increased the percentage of sperm with a high DNA fragmentation index (%DFI), decreased the percentages of motile and viable sperm at thawing (0 hr), but did not affect LPO. H2O2 (150 or 300 µM) increased %DFI after 24 hr. LPO or sperm viability were not affected by H2O2, although most motility parameters decreased. H2O2 decreased the percentage of chlortetracycline pattern F sperm at 4 hr and increased the percentage of acrosome‐reacted sperm (pattern AR) after 1 hr. Pooled data of Experiment 2 showed LPO was positively correlated with SCSA (r = 0.29 to r = 0.59; P < 0.05 to P < 0.01), while most motility parameters and the percentage of viable sperm were negatively correlated with LPO (r = −0.30 to r = −0.38; P < 0.05 to P < 0.01). LPO was positively correlated with the percentage of pattern AR sperm (r = 0.33; P < 0.01). Cryopreservation and H2O2 promote DNA instability in ram sperm, though motility is a more sensitive indicator of oxidative stress than the other parameters investigated. Mol. Reprod. Dev. 74: 878–892, 2007. © 2006 Wiley‐Liss, Inc.