bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nano/Micro Particle Hybrid Composites for Scratch and Abrasion Resistant Polyacrylate Coatings
Authors: Bauer Frank , Flyunt Roman , Czihal Konstanze , Buchmeiser Michael R. , Langguth Helmut , Mehnert Reiner 
Published: May 2006

AbstractSummary: UV curable acrylate formulations with a high content of fumed, nano‐sized silica were prepared to improve their application for abrasion and scratch resistant top coats. Grafting of trialkoxysilanes onto the surface of nanoparticles facilitated their embedding in the formulation and alleviated the effect of undesired increase in viscosity and dilatancy. Modified nanoparticles were obtained from several organosilanes and characterized by a multitechnique approach. To avoid problems during redispersion, in situ modification of nano‐sized silica was performed using the liquid acrylate formulation as a diluting and deagglomerating agent. These nanocomposite materials exhibit markedly improved properties as compared to neat acrylate coatings, e.g. heat, scratch, and abrasion resistance. However, a much better abrasion resistance was obtained for coatings containing both silica nanoparticles and corundum microparticles. By using various grades of corundum, a synergetic effect of nano/micro hybrid composite materials has been studied for parquet and flooring applications.Pictures of neat polyacrylate coating (on the left) and nano/micro hybrid composite material (18 wt.‐% silica +15 wt.‐% corundum) on parquet substrate after Taber Abraser Test.imagePictures of neat polyacrylate coating (on the left) and nano/micro hybrid composite material (18 wt.‐% silica +15 wt.‐% corundum) on parquet substrate after Taber Abraser Test.
Augmented cancer resistance and DNA damage response phenotypes in PPM1D null mice
Authors: Nannenga Bonnie , Lu Xiongbin , Dumble Melissa , Van Maanen Marc , Nguyen Thuy‐Ai , Sutton Richard , Kumar T. Rajendra , Donehower Lawrence A. 
Published: May 2006

AbstractThe p53‐induced serine/threonine phosphatase, protein phosphatase 1D magnesium‐dependent, delta isoform (PPM1D) (or wild‐type p53‐induced phosphatase 1 (Wip1)), exhibits oncogenic activity in vitro and in vivo. It behaves as an oncogene in rodent fibroblast transformation assays and is amplified and overexpressed in several human tumor types. It may contribute to oncogenesis through functional inactivation of p53. Here, we show that the oncogenic function of PPM1D is associated with its phosphatase activity. While overexpressed PPM1D may be oncogenic,PPM1Dnull mice are resistant to spontaneous tumors over their entire lifespan. This cancer resistance may be based in part on an augmented stress response following DNA damage.PPM1Dnull mice treated with ionizing radiation display increased p53 protein levels and increased phosphorylation of p38 MAP kinase, p53, checkpoint kinase 1 (Chk1), and checkpoint kinase 2 (Chk2) in their tissues compared to their wild‐type (WT) counterparts. MalePPM1Dnull mice show a modest reduction in longevity, reduced serum insulin‐like growth factor 1 (IGF‐1) levels, and reduced body weight compared to WT mice. ThePPM1Dnull mouse phenotypes indicate that PPM1D has a homeostatic role in abrogating the DNA damage response and may regulate aspects of male longevity. © 2006 Wiley‐Liss, Inc.
Targeting carcinogenesis: A role for the prolyl isomerase Pin1?
Authors: Lu Kun Ping , Suizu Futoshi , Zhou Xiao Zhen , Finn Greg , Lam Prudence , Wulf Gerburg 
Published: May 2006

AbstractPhosphorylation of proteins on serine or threonine residues that immediately precede proline (pSer/Thr‐Pro) is a central signaling mechanism in cell proliferation and transformation. Recent studies indicate that certain pSer/Thr‐Pro motifs in native proteins exist in two completely distinct conformations, cis and trans, whose conversion is markedly slowed down upon phosphorylation, but specifically catalyzed by the peptidyl‐prolyl cis/trans isomerase Pin1. Importantly, such Pin1‐catalyzed conformational changes can have profound effects on the function of many phosphorylation signaling pathways, thereby playing an important role in various cellular processes. Moreover, increasing evidence indicates that aberrant Pin1 function plays an important role in the pathogenesis of some human diseases. Notably, Pin1 is not only overexpressed in a large number of human cancers, but also is an excellent prognostic marker in some cancers. Furthermore, Pin1 overexpression can function as a critical catalyst that amplifies multiple oncogenic signaling pathways during oncogenesis. Moreover, Pin1 overexpression causes cell transformation, centrosome amplification, genomic instability, and tumor development. In contrast, Pin1 knockout in mice prevents certain oncogenes from inducing tumors and Pin1 inhibition in cancer cells suppresses their cell proliferation, transformed phenotype and tumorigenicity in nude mice as well as increases the response to other anticancer agents. These results suggest that Pin1‐mediated postphosphorylation regulation may provide a unique opportunity for disrupting oncogenic pathways, and thereby represent an appealing target for novel anticancer therapies. © 2006 Wiley‐Liss, Inc.
Roles of reactive oxygen species in hepatocarcinogenesis and drug resistance gene expression in liver cancers
Authors: Tien Kuo M. , Savaraj Niramol 
Published: May 2006

AbstractHepatocellular carcinoma (HCC) has traditionally been an attractive system for cancer research because many animal HCC models are available. It is well known that liver tumors in animals can be induced by many different protocols, such as chronic hepatitis viral infections, carcinogens, toxins, steroid hormones, and dietary intervention. Although these different inducers have different cellular targets and modes of cytotoxic effects, their common denominator is the formation of reactive oxygen species (ROS). In this review, we present compelling evidence to support the hypothesis that ROS play important roles in hepatocarcinogenesis and the associated upregulation of drug resistance gene expression. © 2006 Wiley‐Liss, Inc.
Cerebral plasticity in crossed C7 grafts of the brachial plexus: An fMRI study
Authors: Beaulieu Jean‐Yves , Blustajn Jerry , Teboul Frederic , Baud Patrice , De Schonen Scania , Thiebaud Jean‐Baptiste , Oberlin Christophe 
Published: May 2006

AbstractIn order to rescue elbow flexion after complete accidental avulsion of one brachial plexus, seven patients underwent a neurotization of the biceps with fibers from the contralateral C7 root. The C7 fibers used for the graft belonged to the pyramidal pathway, which descends from the cerebral hemisphere ipsilateral to the damaged plexus, and which controls extension and abduction of the contralateral arm. After several months of reeducation, a functional magentic resonance imaging study was performed with a 1.5 tesla clinical magnetic resonance scan system, in order to investigate the central neural networks involved in the recovery of elbow flexion. Functional brain images were acquired under four conditions: flexion of each of the two elbows, and imagined flexion of each elbow. Results show that flexion of the neurotized arm is associated with a bilateral network activity. The contralateral cortex originally involved in control of the rescued arm still participates in the elaboration and control of the task through the bilateral premotor and primary motor cortex. The location of the ipsilateral clusters in the primary motor, premotor, supplementary motor area, and posterior parietal areas is similar among patients. The location of contralateral activations within the same areas differs across patients. © 2006 Wiley‐Liss, Inc. Microsurgery, 2006.
Metabolism of Maillard reaction products by the human gut microbiota – implications for health
Authors: Tuohy Kieran M. , Hinton Davinia J. S. , Davies Sarah J. , Crabbe M. James C. , Gibson Glenn R. , Ames Jennifer M. 
Published: May 2006

AbstractThe human colonic microbiota imparts metabolic versatility on the colon, interacts at many levels in healthy intestinal and systemic metabolism, and plays protective roles in chronic disease and acute infection. Colonic bacterial metabolism is largely dependant on dietary residues from the upper gut. Carbohydrates, resistant to digestion, drive colonic bacterial fermentation and the resulting end products are considered beneficial. Many colonic species ferment proteins but the end products are not always beneficial and include toxic compounds, such as amines and phenols. Most components of a typical Western diet are heat processed. The Maillard reaction, involving food protein and sugar, is a complex network of reactions occurring during thermal processing. The resultant modified protein resists digestion in the small intestine but is available for colonic bacterial fermentation. Little is known about the fate of the modified protein but some Maillard reaction products (MRP) are biologically active by, e. g. altering bacterial population levels within the colon or, upon absorption, interacting with human disease mechanisms by induction of inflammatory responses. This review presents current understanding of the interactions between MRP and intestinal bacteria. Recent scientific advances offering the possibility of elucidating the consequences of microbe‐MRP interactions within the gut are discussed.
Controlled polymerizations as tools for the design of star‐like and dendrimer‐like polymers
Authors: Taton Daniel , Gnanou Yves , Matmour Rachid , Angot Stéphanie , Hou Sijian , Francis Raju , Lepoittevin Bénédicte , Moinard Delphine , Babin Jérôme 
Published: May 2006

AbstractThis paper highlights our recent efforts to engineer polymer chains in star‐like and dendrimer‐like architectures using atom‐transfer radical polymerization (ATRP) and anionic ring‐opening polymerization (AROP) of ethylene oxide as synthetic tools. The scope and limitations of ATRP are first discussed when this method of controlled radical polymerization is applied to multifunctional initiators for the synthesis of star polymers by the core‐first approach. The switch from ATRP to AROP of ethylene oxide and vice versa allows access to branched amphiphilic block copolymers exhibiting core–shell structures. Stress is also put on the methodologies for the selective branching of polymeric chain‐ends, with a view to introducing ω‐geminal functionalities from which further polymer branches can be grown. When linear polymer precursors are used, such a strategy leads to asymmetric and mikto‐arm stars but the same can be applied to multi‐arm stars so as to generate so‐called ‘dendrimer‐like (co)polymers’ that are dendrimers with true macromolecular generations. Copyright © 2006 Society of Chemical Industry
Study on hyperbranched polyesters as rheological modifier for Spandex spinning solution
Authors: Han Keqing , Li Wenjiang , Wu Chengxun , Yu Muhuo 
Published: May 2006

AbstractThe rheological behavior of polyurethane (PU)/N,N‐dimethylformamide (DMF) spinning solutions with various contents of hyperbranched polyesters was studied using a RS150L‐controlled stress rotational rheometer. The results showed that the viscosity of the spinning solutions could be greatly reduced by adding hyperbranched polyesters even at 0.5 wt% loading. The zero‐shear viscosity of solutions with hyperbranched polyesters was much lower than that of pure PU/DMF solution, which indicated a lower degree of entanglement when solutions were in a static state. The apparent activation energy of viscous flow and the critical shear rate for shear thinning of solutions with hyperbranched polyesters were much lower than that for pure PU/DMF solution, which indicated a weaker entanglement structure formed. In addition, the effect of hyperbranched polyesters on the mechanical properties of Spandex fiber was discussed. Copyright © 2006 Society of Chemical Industry
Styrene–substituted‐styrene copolymerization using diphenylzinc–metallocene–methylaluminoxane systems
Authors: Rabagliati Franco M , Rodríguez Francisco J , Alla Abdel , Muñoz‐Guerra Sebastián 
Published: May 2006

AbstractHomopolymerization of disubstituted styrenes (2,4‐ and 2,5‐dimethylstyrene) and trisubstituted styrene (2,4,6‐trimethylstyrene) and their copolymerization with styrene were carried out using diphenylzinc–metallocene–methylaluminoxane initiator systems for metallocene (n‐BuCp)2TiCl2 and for half‐metallocene CpTiCl3. The studied comonomers were found to be less reactive than p‐tertbutylstyrene, p‐methylstyrene and styrene. The results indicate that, even though the methyl group has I+ inductive effect, di‐ and tri‐methylstyrenes are reluctant to undergo either homopolymerization or copolymerization. This behavior suggests that the reactivity is regulated not only by the inductive effect of the alkyl group but also by the steric impediment caused by the crowding of the substituents on the benzene ring. Copyright © 2006 Society of Chemical Industry
Preparation and characterization of ultrafine electrospun polyacrylonitrile fibers and their subsequent pyrolysis to carbon fibers
Authors: Sutasinpromprae Juthawan , Jitjaicham Sujinda , Nithitanakul Manit , Meechaisue Chidchanok , Supaphol Pitt 
Published: May 2006

AbstractThe present contribution reports the fabrication and characterization of ultrafine polyacrylonitrile (PAN) fibers by electrospinning and further development of the as‐spun PAN fibers into ultrafine carbon fibers. The effects of solution conditions (i.e., solution concentration, viscosity, conductivity, and surface tension) and process parameters (i.e., applied electrostatic field strength, emitting electrode polarity, nozzle diameter, and take‐up speed of a rotating‐drum collector) on morphological appearance and average diameter of the as‐spun PAN fibers were investigated by optical scanning (OS) and scanning electron microscopy (SEM). The concentration, and hence the viscosity, of the spinning solutions significantly affected the morphology and diameters of the as‐spun PAN fibers. The applied electrostatic field strength and nozzle diameter slightly affected the diameters of the as‐spun fibers, while the emitting electrode polarity did not show any influence over the morphology and size of the as‐spun fibers. Utilization of the rotating‐drum collector enhanced the alignment of the as‐spun fibers. Within the investigated concentration range, the average diameter of the fibers ranged between 80 and 725 nm. Finally, heat treatment of the as‐spun fibers with their average diameter of about 450 nm was carried out at 230 and 1000 °C, respectively. Various characterization techniques revealed successful conversion into carbon fibers with an average diameter of about 250 nm. Copyright © 2006 Society of Chemical Industry
Mutation of Phe102 to Ser in the carboxyl terminal helix of Escherichia coli thioredoxin affects the stability and processivity of T7 DNA polymerase
Authors: Chiu Joyce , Tillett Daniel , March Paul E. 
Published: May 2006

AbstractProcessivity of T7 DNA polymerase relies on the coupling of its cofactor Escherichia coli thioredoxin (Trx) to gene 5 protein (gp5) at 1:1 stoichiometry. We designed a coexpression system for gp5 and Trx that allows in vivo reconstitution of subunits into a functional enzyme. The properties of this enzyme were compared with the activity of commercial T7 DNA polymerase. Examination of purified enzymes by sodium dodecyl sulfate–polyacrylamide gel electrophoresis revealed that the thioredoxin subunit of the two enzymes did not comigrate. To our surprise, we identified a mutation (Phe102 to Ser) in the Trx component from the commercial T7 DNA polymerase (gp5/TrxS102) that was not in the enzyme from the coexpression system (wild type gp5/Trx). A comparison of polymerase activity of the T7 DNA polymerases shows that both enzymes possessed similar specific activity but they were different in their residual activity at 37°C. The half‐life of gp5/TrxS102 was 7 min at 37°C and 12 min for gp5/Trx. gp5/TrxS102 polymerase activity was reduced by fourfold with 3′–5′ exonuclease activity as the prominent activity detected after 10 min of heat inactivation at 37°C. Supplementation of reaction mixtures containing gp5/TrxS102 with exogenous nonmutant thioredoxin restored the enzyme activity levels. Pulse proteolysis was used to demonstrate that TrxS102 unfolded at lower urea concentrations than wild type thioredoxin. Thus, Ser substitution at position 102 affected the structural stability of thioredoxin resulting in a reduced binding affinity for gp5 and loss of processivity. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Transport properties of some rare‐earth mono and bilayer manganite films
Authors: Taran Subhrangsu , Karmakar S. , Chou H. , Chaudhuri B. K. 
Published: May 2006

AbstractWe report the transport properties of both single‐layer (SL) La0.67Sr0.33MnO3 (SL1), La0.67Ca0.33MnO3 (SL2) and La0.67Sr1.33MnO4 (SL3) each of thickness 135 nm and bilayers (BL) SL1/SL3 (BL1) and SL2/SL3 (BL2) each of thickness 270 nm. All the films are deposited on SrTiO3(001) substrates by the off‐axis RF sputtering process. Compared to SL films, a large enhancement of magnetoresistance (MR) at 1.2 T field is observed in the BL films. Except for the antiferromagnetic (AF) SL3 film, two ferromagnetic (FM) films SL1 and SL2 showed metallic transitions, respectively, at T MI = 248 and 365 K. For the BL films, T MI shifts largely towards a lower temperature than the corresponding T MI of the corresponding SL films due to the increase of disorder and strain effect at the junction of the films. Temperature‐dependent resistivity (ρ ) curves, above T MI, are best fitted by the adiabatic small‐polaron hopping model, i.e. ρ = ρ 0T exp (E a/k BT ) with activation energy E a (BL) > E a(SL). Within the temperature range T D/2 < T < T MI (T D being the Debye temperature), the resistivity curves are well fitted with the variable range hopping (VRH) with effective number of carriers at the Fermi level [N (E F)], being different for BL and SL films. In the SL films, spin ordering completes below a critical temperature (T *, say) and a changeover of the transport mechanism dominated by the electron–electron scattering regime (T < T *) to an electron–magnon‐dominated scattering regime (T > T *) is observed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A two‐degree‐of‐freedomℋ︁∞control design method for robust model matching
Authors: Dehghani Arvin , Lanzon Alexander , D. O. Anderson Brian 
Published: May 2006

AbstractWe propose anℋ︁∞controller design method which achieves a closed‐loop transfer function equal or otherwise sensibly close to a desired transfer function, viz. a model reference design. The proposed controller design method inherits the model reference feature of the internal model control design method and incorporates the weighting scheme of theℋ︁∞loop‐shaping. It utilizes Youla–Kucera parameterization in a two‐degree‐of‐freedom scheme to achieve robust model reference and high performance design while ensuring a sensible robust stability margin, and can be readily applied to the generic class of LTI systems (SISO, MIMO, stable, unstable). Copyright © 2006 John Wiley & Sons, Ltd.
Explicit robust model predictive control using recursive closed‐loop prediction
Authors: Chu Danlei , Chen Tongwen , Marquez Horacio J. 
Published: May 2006

AbstractIn this paper, we develop an algorithm to compute robust MPC explicit solutions for constrained MIMO systems with internal uncertainties and external disturbances. Our approach is based on a recursive closed‐loop prediction strategy to realize a finite horizon robust MPC regulator, which has the feature that only one‐step state prediction is sufficient to realize robust MPC with an arbitrary prediction horizon. The paper defines a set of recursive sub‐optimization problems as multiple‐parametric sub‐quadratic programming (mp‐SQP), and shows that the optimal solution to the mp‐SQP problem is piecewise affine functions of states, associated with piece objectives and state critical regions. Asymptotic closed‐loop stability can be guaranteed by a terminal weighting and a terminal feedback gain; also by introducing two tuning variables, the algorithm is capable of adjusting the trade‐off between system performance and robustness. The state admissible set, which is not easily derived from physical vision, is constructed by two methods: a piecewise linear norm of signals, and polyhedral Voronoi sets. Finally, two simulation examples demonstrate that the algorithm is efficient, feasible and flexible, and can be applied to both slow and fast industrial MIMO systems. Copyright © 2006 John Wiley & Sons, Ltd.
Determination of Amylose Content in Different Starches Using Modulated Differential Scanning Calorimetry
Authors: Moorthy Subramoney N. , Andersson Lena , Eliasson Ann‐Charlotte , Santacruz Stalin , Ruales Jenny 
Published: May 2006

AbstractA simple calorimetric method for determination of amylose content in starch is reported. Starches were heated in the presence of two common surfactants, viz., sodium dodecyl sulphate (SDS) and cetyltrimethylammonium bromide (CTAB), and the enthalpies of melting of the amylose‐surfactant complexes were determined using Modulated Differential Scanning Calorimetry (MDSC). A large number of native starches including cereal, root and pea starches were examined. The results were compared with those obtained by iodimetry and gel permeation chromatography (GPC) for all the starches. There was a good correlation between the values from iodimetry and GPC with those obtained using the surfactants. Both surfactants seemed to work equally well, even for those starches with about 40% amylose content. However, in case of SDS higher standard deviations were usually obtained than for CTAB in the determination of transition enthalpies.
Placental volume in twin and triplet pregnancies measured by three‐dimensional ultrasound at 11 + 0 to 13 + 6 weeks of gestation
Authors: Wegrzyn P. , Fabio C. , Peralta A. , Faro C. , Borenstein M. , Nicolaides K. H. 
Published: May 2006

AbstractObjectiveTo compare the placental volume at 11 + 0 to 13 + 6 weeks' gestation between singleton and multiple pregnancies and to examine the possible effect of chorionicity on placental volume.MethodsThe placental volume was measured by three‐dimensional (3D) ultrasound using the Virtual Organ Computer‐aided AnaLysis (VOCAL) technique in 290 consecutive twin and 37 triplet pregnancies at 11 + 0 to 13 + 6 weeks of gestation. For the comparison of twin, triplet and singleton placental volumes each measurement was expressed as a multiple of the median (MoM) for singletons, previously established from the study of 417 normal fetuses at 11 + 0 to 13 + 6 weeks of gestation.ResultsMedian twin and triplet placental volumes were 1.66 and 2.28 MoM for singletons, respectively. In twins the placental volumes increased significantly with gestation from a median of 83.6 mL (5th and 95th centiles: 56.0 mL and 124.9 mL) at 11 + 0 weeks to 149.3 mL (5th and 95th centiles: 100.0 mL and 223.1 mL) at 13 + 6 weeks. The median MoM in monochorionic twins was not significantly different from that in dichorionic twins with fused placentas or dichorionic twins with separate placentas. In triplets the placental volumes increased significantly with gestation from a median of 114.9 mL (5th and 95th centiles: 77.6 mL and 170.1 mL) at 11 weeks to 217.9 mL (5th and 95th centiles: 147.2 mL and 322.5 mL) at 13 + 6 weeks. There were no significant differences in total placental volume between monochorionic and dichorionic triplets, monochorionic and trichorionic triplets, or dichorionic and trichorionic triplets.ConclusionsPlacental volume in multiple pregnancies does not depend on chorionicity, and the rate of placental growth between 11 and 13 + 6 weeks is not significantly different between singletons, twins and triplets. Moreover, for a given gestational age the placental volume corresponding to each fetus in twins and triplets is 83% and 76%, respectively, of the placental volume in singletons. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.