bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reactivities of acridine compounds in hydride transfer reactions
Authors: Lee In‐Sook Han , Kil Hyun Joo , Ji Young Ran 
Published: May 2007

AbstractReactivities of acridine derivatives (10‐benzylacridinium ion, 1a+, 10‐methylacridinium ion, 1b+, and 10‐methyl‐9‐phenylacridinium ion, 1c+) have been compared quantitatively for hydride transfer reactions with 1,3‐dimethyl‐2‐substituted phenylbenzimidazoline compounds, 2Ha–h. Reactions were monitored spectrophotometrically in a solvent consisting of four parts of 2‐propanol to one part of water by volume at 25 ± 0.1 °C. Reduction potentials have been estimated for acridine derivatives by assuming that the equilibrium constants for the reductions of 1a+–c+ by 2Hb would be the same in aqueous solution and accepting −361 mV as the reduction potential of the 1‐benzyl‐3‐carbamoylpyridinium ion. The resulting reduction potentials, E, are −47 mV for 1a+, −79 mV for 1b+, and −86 mV for 1c+. Each of acridine derivatives gives a linear Brønsted plot for hydride transfer reactions. The experimental slopes were compared with those obtained by Marcus theory. This comparison shows that the kinetic data are consistent with a one‐step mechanism involving no high‐energy intermediates. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis and characterization of graft copolymers containing poly(p‐phenylene) main chains and mesogen‐jacketed liquid‐crystalline polystyrene side chains
Authors: Sun Li‐Mei , Fan Xing‐He , Chen Xiao‐Fang , Liu Xiang‐Feng , Zhou Qi‐Feng 
Published: May 2007

AbstractA series of novel comblike mesogen‐jacketed liquid‐crystalline graft copolymers, poly(p‐phenylene)‐g‐poly{2,5‐bis[(4‐methoxyphenyl)oxycarbonyl]styrene} (PPP‐g‐PMPCS) copolymers, have been designed and successfully synthesized by a Yamamoto coupling reaction and subsequent atom transfer radical polymerization (ATRP). 1H NMR spectroscopy, ultraviolet–visible spectra, and gel permeation chromatography (GPC) have been used to confirm the molecular structure of the macroinitiator and the copolymers. A study of the polymerization kinetics of ATRP has shown that the molecular weight of the copolymer increases linearly with the conversion of the monomer, whereas the polydispersity remains narrow (≤1.28), indicating that the ATRP of 2,5‐bis[(4‐methoxyphenyl)oxycarbonyl]styrene is well controlled. Thermogravimetric analysis and differential scanning calorimetry (DSC) measurements have indicated that the PPP‐g‐PMPCS copolymers have better thermal stabilities than the macroinitiator, and their thermal stabilities increase with increasing molecular weight. The liquid‐crystalline behavior has been examined with polarized optical microscopy, DSC, one‐dimensional wide‐angle X‐ray diffraction (1D WAXD), and two‐dimensional wide‐angle X‐ray diffraction (2D WAXD). The results show that all the comblike copolymers exhibit obvious liquid‐crystalline behaviors, even though the GPC molecular weight of the segments of poly{2,5‐bis[(4‐methoxyphenyl)oxycarbonyl]styrene} (PMPCS) have been determined to be far less than the critical value of linear PMPCS. Moreover, 1D WAXD measurements show that the temperature at which the comblike mesogen‐jacketed liquid‐crystalline copolymers can transform into a liquid‐crystalline phase is low; about 20 °C in comparison with the linear ones. 2D WAXD analysis has revealed that these comblike copolymers should be assigned to a hexatic columnar nematic (ΦHN) phase. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2543–2555, 2007
End‐functional poly(methyl methacrylate)s via group transfer polymerization
Authors: Gnaneshwar Rudhramyna , Sivaram Swaminathan 
Published: May 2007

AbstractHydroxyl‐, amine‐, and lactone‐end‐functional poly(methyl methacrylate)s (PMMA) were prepared with controlled molecular weights and Mw/Mn = 1.06–1.19 via group transfer polymerization. This was achieved by the electrophilic termination of silyl ketene acetal ended PMMAs with benzaldehyde, N‐trimethylsilyl benzaldimine, and 5,6‐dihydro‐2H‐pyran‐2‐one, respectively. The number‐average degree of functionalization, as determined by NMR/SEC, was in the range of 0.70–0.85. A Lewis acid was used for terminating silyl ketene acetal ended PMMA with N‐trimethylsilyl benzaldimine, whereas tetra‐n‐butyl ammonium bibenzoate was used in the case of benzaldehyde and 5,6‐dihydro‐2H‐pyran‐2‐one. MALDI‐TOF MS analysis of the end‐functional polymers indicated the competing formation of cyclic end groups due to a back‐biting reaction along with end‐functional PMMAs. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2514–2531, 2007
Quantitative approaches to particle cavitation, shear yielding, and crazing in rubber‐toughened polymers
Authors: Bucknall C. B. 
Published: May 2007

AbstractModels for rubber particle cavitation, shear yielding, and crazing are reviewed, and their ability to predict the large‐strain deformation behavior of toughened polymers is discussed. An existing model for void initiation and expansion in rubber particles correctly predicts the observed trends: cavitation resistance increases when either the shear modulus or the surface energy of the rubber is increased, or the particle size is reduced. However, further work is needed to improve quantitative modeling of the thermally‐ and stress‐activated void nucleation step. Shear yielding, which is also a rate process, is much better understood; here, the main problems in modeling relate to the formation and evolution of porous shear bands. Craze growth and failure are also reasonably well understood, but previous attempts at modeling have been hampered by uncertainties about craze initiation. To overcome these difficulties, a new theory of crazing is proposed, which treats initiation as a fracture process, and defines a new materials property, Gnasc, the energy required to form unit area of nascent craze. Because nascent crazes are ∼20 nm thick, Gnasc is low: calculations give values <0.5 J m−2 for polystyrene. A new criterion incorporating a plasticity factor fits the data of Sternstein and coworkers on crazing under biaxial loading. In combination with theories of particle cavitation and shear yielding, the fracture mechanics model explains why the balance between crazing and shear yielding is governed by particle size, for example in ABS. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1399–1409, 2007
The effect of oxytocin on cell proliferation in the human prostate is modulated by gonadal steroids: implications for benign prostatic hyperplasia and carcinoma of the prostate
Authors: Whittington Kate , Connors Belinda , King Keith , Assinder Steve , Hogarth Karole , Nicholson Helen 
Published: May 2007

AbstractBACKGROUNDOxytocin (OT) is implicated in regulating prostate growth. OT concentrations are increased in benign, and decreased in malignant prostate disease. This study investigated whether the altered concentrations of OT present in prostate disease affect the proliferation of malignant and non‐malignant human prostate cells.METHODSThe effects of varying concentrations of OT and gonadal steroids on cell proliferation of non‐malignant prostatic epithelial (PrEC) and stromal (PrSC) cells and androgen dependent (LNCaP) and independent (PC‐3) malignant cell lines were assessed.RESULTSOT (>0.5 nmol · L−1) had no effect on PrEC proliferation when cells were cultured alone. When co‐cultured with PrSC and gonadal steroids, OT inhibited epithelial cell proliferation. OT inhibited PrSC proliferation, when cells were cultured alone. When PrSC were co‐cultured in the presence of estrogen physiological concentrations of OT were inhibitory. No effect on cell proliferation was observed with higher concentrations of OT. OT did not affect the proliferation of malignant cell lines in the absence of androgens but, in the presence of testosterone, low concentrations of OT (<1 nmol · L−1) stimulated proliferation of PC‐3 cells. Disruption of caveolae in the plasma membrane removed the inhibitory effect of OT on PrSC proliferation but did not affect the stimulatory effect of OT on PC‐3 cells cultured in the presence of androgens.CONCLUSIONSChanges in prostatic concentrations of OT that occur with aging and malignant disease may act to facilitate cell proliferation. The localization of the OT receptor within the plasma membrane modulates OT's proliferative response in the prostate. Prostate 67: 1132–1142, 2007. © 2007 Wiley‐Liss, Inc.
Molecular properties of two proteins homologous to PduO‐type ATP:cob(I)alamin adenosyltransferase from Sulfolobus tokodaii
Authors: Tanaka Yoshikazu , Sasaki Takashi , Kumagai Izumi , Yasutake Yoshiaki , Yao Min , Tanaka Isao , Tsumoto Kouhei 
Published: May 2007

AbstractIn the thermophilic archaeon Sulfolobus tokodaii, there are two genes homologous to PduO‐type ATP:cob(I)alamin adenosyltransferase, ST1454 and ST2180. To address the structure and function of these two sequence‐related proteins from one organism, we prepared them by using the Escherichia coli expression system and analyzed them by immunoblotting, matrix‐assisted laser desorption ionization‐time‐of‐flight mass spectroscopy, circular dichroism spectrometry, ATP:cobalamin adenosyltransferase assay, and X‐ray crystallography. Immunoblotting and matrix‐assisted laser desorption ionization‐time‐of‐flight mass spectroscopy analyses showed that both these proteins are expressed in S. tokodaii cells as soluble proteins and are spontaneously digested at the N‐terminal region. ATP:cob(I)alamin adenosyltransferase activity was detected for ST1454 but not for ST2180. ST2180 reduced the concentration of cob(I)alamin, suggesting that ST2180 might recognize cob(I)alamin as a ligand. The secondary structure of ST1454 was retained even in 7 M guanidine hydrochroride, whereas that of ST2180 was melted in 4.5 M guanidine hydrochloride. The X‐ray crystal structural analysis revealed that the proteins shared a common structure: a trimer of five‐helix bundles with a clockwise kink. There is a pocket surrounded by highly conserved residues, in which a polypropylene glycol 400 in the crystal structure of ST1454 was captured, suggesting that it is an active site. Structural comparison between these two proteins showed the difference in the number of ion pairs around the proposed active site. On the basis of these results, we propose that ST1454 and ST2180 have related but distinct functions. Proteins 2007. © 2007 Wiley‐Liss, Inc.
Second‐order sliding mode control of underactuated mechanical systems I: Local stabilization with application to an inverted pendulum
Authors: Riachy Samer , Orlov Yuri , Floquet Thierry , Santiesteban Raul , Richard Jean‐Pierre 
Published: May 2007

AbstractSecond‐order sliding mode control synthesis is developed for underactuated mechanical systems, operating under uncertainty conditions. In order to locally stabilize an underactuated system around an unstable equilibrium, an output is specified in such a way that the corresponding zero dynamics is locally asymptotically stable. Then, the desired stability property of the closed‐loop system is provided by applying a quasihomogeneous second‐order sliding mode controller, driving the system to the zero dynamics manifold in finite time. Although the present synthesis exhibits an infinite number of switches on a finite time interval, it does not rely on the generation of first‐order sliding modes, while providing robustness features similar to those possessed by their standard sliding mode counterparts. A second‐order sliding mode appears on the zero dynamics manifold which is of co‐dimension greater than the control space dimension. Performance issues of the proposed synthesis are illustrated in numerical and experimental studies of a cart–pendulum system. Copyright © 2007 John Wiley & Sons, Ltd.
Decentralized MPC of nonlinear systems: An input‐to‐state stability approach
Authors: Raimondo D.M. , Magni L. , Scattolini R. 
Published: May 2007

AbstractThis paper presents stabilizing decentralized model predictive control (MPC) algorithms for discrete‐time nonlinear systems. The overall system under control is composed by a number of subsystems, each one locally controlled with an MPC algorithm guaranteeing the input‐to‐state stability (ISS) property. Then, the main stability result is derived by considering the effect of interconnections as perturbation terms and by showing that also the overall system is ISS. Both open‐loop and closed‐loop min–max formulations of robust MPC are considered. Copyright © 2007 John Wiley & Sons, Ltd.
Simultaneous ℋ︁2/ℋ︁∞ control of uncertain jump systems with functional time‐delays
Authors: Mahmoud Magdi S. , Shi Peng , Boukas El Kebir , Jain Lakhim 
Published: May 2007

AbstractThis paper presents new results pertaining to the control design of a class of linear uncertain systems with Markovian jump parameters. An integral part of the system dynamics is a delayed state in which the time‐delays are mode dependent. The jumping parameters are modelled as a continuous‐time, discrete‐state Markov process and the uncertainties are norm‐bounded. We construct an appropriate Lyapunov–Krasovskii functional and design a simultaneous ℋ︁2/ℋ︁∞ controller which minimizes a quadratic ℋ︁2 performance measure while satisfying a prescribed ℋ︁∞‐norm bound on the closed‐loop system. It is established that sufficient conditions for the existence of the simultaneous ℋ︁2/ℋ︁∞ controller and the associated performance upper bound are cast in the form of linear matrix inequalities. Simulation results are provided and extension to the case where the jumping rates are subject to uncertainties is presented. Copyright © 2007 John Wiley & Sons, Ltd.
Biomimetic Models of the Actin Cytoskeleton
Authors: Mohrdieck Camilla , Dalmas Florent , Arzt Eduard , Tharmann Rainer , Claessens Mireille M. A. E. , Bausch Andreas R. , Roth Alexander , Sackmann Erich , Schmitz Christian H. J. , Curtis Jennifer , Roos Wouter , Schulz Simon , Uhrig Kai , Spatz Joachim P. 
Published: May 2007

AbstractThe cytoskeleton is a complex polymer network that plays an essential role in the functionality of eukaryotic cells. It endows cells with mechanical stability, adaptability, and motility. To identify and understand the mechanisms underlying this large variety of capabilities and to possibly transfer them to engineered networks makes it necessary to have in vitro and in silico model systems of the cytoskeleton. These models must be realistic representatives of the cellular network and at the same time be controllable and reproducible. Here, an approach to design complementary experimental and numerical model systems of the actin cytoskeleton is presented and some of their properties discussed.
Install or invoke?: The optimal trade‐off between performance and cost in the design of multi‐standard reconfigurable radios
Authors: Rodriguez Virgilio , Moy Christophe , Palicot Jacques 
Published: May 2007

AbstractWe approach the design of multi‐standard reconfigurable radio as a choice between two extremes: (a) installing complex, self‐contained dedicated components that provide high performance at a high cost (‘Velcro approach’), versus (b) supporting all targeted standards through primitive lower level components, which reduces cost but maximises latency. To find the optimal trade‐off between performance and cost, we build a mathematical model, in which we represent the design choices through a graph of progressively simpler functional modules. We illustrate our approach through a simple but realistic design example. Additionally, we show that this optimisation can be reformulated as a version of the well‐known network‐design problem, which opens the door to a wealth of results, algorithms and experience, already available in the scientific literature. We identify some specific algorithms that can help us find the optimal design and discuss limitations and future directions of our research program. Copyright © 2007 John Wiley & Sons, Ltd.
On channel adaptive energy management with available bandwidth estimation in wireless sensor networks
Authors: Lin Xiao‐Hui , Kwok Yu‐Kwong , Wang Hui 
Published: May 2007

AbstractTo enhance the lifetime of a sensor network which consists of hundreds or even thousands of resource‐limited devices, energy efficient communication is mandatory. Despite that a plethora of work has been done in designing energy efficient protocols for sensor networks, the time‐varying nature of wireless channel is largely unexplored. Indeed, we believe that a cross‐layer design on power aware communication is necessary to further optimize energy usage. In this paper, we propose a new channel adaptive power aware protocol, called CAEM, which works by dynamically adjusting the data throughput under different channel conditions with the help of an adaptive channel coding and modulation facility. Each sensor device judiciously accesses the wireless medium in that communication activity is reduced for devices under poor channel conditions. Simulation results indicate that the proposed CAEM protocol can lead to energy conservation by as much as 30 per cent. Furthermore, CAEM is also efficient in channel utilization as it generates a higher data throughput even under heavy traffic load. Copyright © 2007 John Wiley & Sons, Ltd.
When are ant‐attractant devices a worthwhile investment?Vicia fabaextrafloral nectaries andLasius nigerants
Authors: Oliver Thomas H. , Cook James M. , Leather Simon R. 
Published: May 2007

AbstractMost studies aiming to determine the beneficial effect of ants on plants simply consider the effects of the presence or exclusion of ants on plant yield. This approach is often inadequate, however, as ants interact with both non‐tended herbivores and tended Homoptera. Moreover, the interaction with these groups of organisms is dependent on ant density, and these functional relationships are likely to be non‐linear. A model is presented here that segregates plant herbivores into two categories depending on the sign of their numerical response to ants (myrmecophiles increase with ants, non‐tended herbivores decline). The changes in these two components of herbivores with increasing ant density and the resulting implications for ant‐plant mutualisms are considered. It emerges that a wide range of ant densities needs to be considered as the interaction sign (mutualism or parasitism) and strength is likely to change with ant density. The model is used to interpret the results of an experimental study that varied levels ofAphis fabaeinfestation andLasius nigerant attendance onVicia fababean plants. Increasing ant density consistently reduced plant fitness and thus, in this location, the interaction between the ants and the plant can be considered parasitic. In theVicia fabasystem, these costs of ants are unlikely to be offset by other beneficial agents (e.g., parasitoids), which also visit extrafloral nectaries.
Comparing Subcutaneous Adipose Tissue in Beef and Muskox with Emphasis on trans 18:1 and Conjugated Linoleic Acids
Authors: Dugan Michael E. R. , Kramer John K. G. , Robertson Wayne M. , Meadus William J. , Aldai Noelia , Rolland David C. 
Published: May 2007

AbstractMuskox (Ovibos moschatus) are ruminant animals native to the far north and little is known about their fatty acid composition. Subcutaneous adipose tissue (backfat) from 16 wild muskox was analyzed and compared to backfat from 16 barley fed beef cattle. Muskox backfat composition differed substantially from beef and the most striking difference was a high content of 18:0 (26.8 vs. 9.77%). This was accompanied by higher levels of most other saturated fatty acids except beef had more 16:0. Muskox backfat also had a lower level of cis‐18:1 and this was related to a lower expression of steroyl‐CoA desaturase mRNA. Beef backfat had a higher level of total trans‐18:1 (4.25 vs. 2.67%). The most prominent trans‐18:1 isomers in beef backfat were 10t‐18:1 (2.13%) and 11t‐18:1 (0.77%) whereas the most prominent isomers in muskox backfat were 11t‐18:1 (1.41%), 13t/14t‐ (0.27%) and 16t‐18:1 (0.23%). The total conjugated linoleic acid (CLA) content was higher in beef backfat than muskox (0.67 vs. 0.50%) with 9c,11t‐18:2 as the most abundant CLA isomer. The second most abundant CLA isomer in beef backfat was 7t,9c‐18:2 (0.10%) whereas in muskox it was 11t13c‐18:2 (0.04%). Muskox backfat had a higher content of 18:3n‐3 and its elongation and desaturation products 20:5n‐3, 22:5n‐3 and 22:6n‐3 and a lower n‐6/n‐3 ratio. Overall, the high forage diet of muskox seemed to produce a healthier fatty acid profile and highlighted the need to develop feeding strategies for intensively raising beef that will not negatively impacting fatty acid composition.
Identifying estrogen receptor target genes
Authors: Welboren Willem-Jan , Stunnenberg Henk G. , Sweep Fred C.G.J. , Span Paul N. 
Published: May 2007

AbstractThe estrogen receptor (ER) is a ligand inducible transcription factor that regulates a large number of target genes. These targets are particularly relevant in breast cancer, where the sensitivity of the tumor to estrogens determines whether the patients can be treated with endocrine therapy such as tamoxifen. Identifying genomic ER targets is a daunting task. Quantifying expression levels of suspected target genes after estradiol stimulation or, more recently, using expression microarrays to this effect will reveal which genes are regulated by estradiol, however, without discriminating between direct and indirect targets. The identification of the palindromic sequence that defines the estrogen responsive element (ERE) allows for the in silico discovery of putative ER targets in the genome. However the ER can also bind imperfect EREs and half sites, and can bind indirectly via other factors. Chromatin immunoprecipitation (ChIP) can yield all ER genomic target sites. Coupling of ChIP with genome‐wide tiling arrays allows for the genome‐wide unbiased identification of direct ER target sequences.
THE ‘OLD’ BRITISH HISTORIES?
Authors: OHLMEYER JANE H. 
Published: May 2007

Protestant war: the ‘British’ of Ireland and the wars of the three kingdoms. By Robert Armstrong. Manchester: Manchester University Press, 2005. Pp. viii+261. ISBN 0-7190-6983-1. £55.00.The origins of sectarianism in early modern Ireland. Edited by Alan Ford and John McCafferty. Cambridge: Cambridge University Press, 2005. Pp. ix+249. ISBN 0-521-83755-3. £50.00.Scottish communities abroad in the early modern period. Edited by Alexia Grosjean and Steve Murdoch. Leiden: Brill Academic Press, 2005. Pp. xxi+417. ISBN 90-04-14306-8. €147.00.Lord Broghill and the Cromwellian union with Ireland and Scotland. By Patrick Little. Woodbridge: Boydell Press, 2004. Pp. xvi+270. ISBN 184383099X. £50.00.The British revolution, 1629–1660. By Allan Macinnes. Houndsmills: Palgrave Macmillan, 2005. Pp. xi+337. ISBN 0-333-59749-4. £59.50.1659: the crisis of the Commonwealth. By Ruth E. Mayers. Woodbridge: Boydell Press, 2004. Pp. xii+306. ISBN 0861932684. £45.00.The English Atlantic in an age of revolution, 1640–1661. By Carla Gardina Pestana. Cambridge, MA: Harvard University Press, 2004. Pp. xiii+342. ISBN 0-674-01502-9. £32.95.Politics and war in the three Stuart kingdoms, 1637–1649. By David Scott. Houndsmills: Palgrave Macmillan, 2004. Pp. xiv+233. ISBN 0-333-65873-6. £52.50.The Irish and British wars, 1637–1654: triumph, tragedy, and failure. By Scott Wheeler. London: Routledge, London, 2002. Pp. x+272. ISBN 0415221315. £32.50.Britain in revolution, 1625–1660. By Austin Woolrych. Oxford: Oxford University Press, 2002. Pp. xi+814. ISBN 0-19-820081-1. £25.00.