bluuebunny/crossref_metadata_2025 huggingface dataset:
Site symmetries of vanadium ions in La3Ga5.5Ta0.5O14 single crystals
Authors: Fuks H. , Kaczmarek S. M. , Berkowski M.
Published: September 2006

Vanadium‐doped La3Ga5.5Ta0.5O14 single crystal (0.05 mol% in the melt with respect to Ga) grown by the Czochralski method has been investigated using electron paramagnetic resonance (EPR) and optical absorption measurements. The optical energy gap of pure La3Ga5.5Ta0.5O14 single crystal is equal to 4.94 eV, while the value for vanadium‐doped La3Ga5.5Ta0.5O14 single crystal is 3.44 eV. Optical absorption measurements have revealed 444 nm, 700 nm and 1100 nm bands arising mainly from V3+ ions at octahedral sites. Moreover, V4+ ions were found at octahedral sites (525 nm band) for the “as‐grown” crystals and at tetrahedral positions (380 nm CT band and 600‐ and 800 nm dd transitions) for crystals irradiated with γ‐quanta with a dose of 1.2 × 105 Gy. The X‐band EPR measurements have been done at room temperature while rotating the single‐crystal sample around a, b * and c crystal axes. For each rotation direction the observed spectra consist of an intense multiline signal centred at ∼340 mT and a second, weak one at ∼150 mT. The dominant signal can be ascribed to the V4+ ions (S = 1/2, I = 7/2) occupying the Ga1, Ta octahedral positions, with an axial D 3 point symmetry. The principal tensor values are determined as g ∥ = 1.925(5), g ⊥ = 1.958(5), A ∥ = 17.0(5) mT and A ⊥ = 5.8(5) mT. Each principal axis of the vanadium paramagnetic centres indeed reveals three different orientations in La3Ga5.5Ta0.5O14 crystal with respect to the space orientation of the Ga3 tetrahedra connected with the Ga1 octahedron. The low‐field resonance signal could neither be ascribed to iron impurities nor to the V4+ ions (S = 1/2, I = 7/2) occupying other (tetrahedral) positions simultaneously creating the vacancy state. This signal was too weak to perform detailed analysis. There are also presented low‐temperature EPR spectra that did not reveal any new lines. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of acceptor and donor dopants on ferroelectric and piezoelectric properties of lead zirconate titanate ceramics
Authors: Ramam Koduri , Lopez Marta
Published: September 2006

Dielectric, ferroelectric and piezoelectric properties of Pb1−x Lax (Zry Ti1−y )1−(x /4)−(3/4)z Fez O3 ceramics for z = 0 to 6 mol% prepared by a mixed oxide method were investigated. Fe substitution in lead lanthanum zirconate titanate (PLZT) compositions resulted in a phase transformation from coexisting phases (ferroelectric rhombohedral (FERH) and ferroelectric tetragonal (FETET)) to intensified tetragonal phase. Grain size and apparent density increased with increasing acceptor (Fe) content up to 3 mol% in the PLZT system. The optimum dielectric properties (ϵ RT, ϵ Tc and tan δ) were observed in 3 mol% Fe‐doped PLZT composition and then decreased thereafter. Acceptor (Fe) substitution in the PLZT system influenced the ferroelectric remanent polarization (P r) and spontaneous (P s) polarization, reaching saturation at 6 mol% Fe, while the coercive field (E c) increased up to 3 mol% Fe‐doped PLZT composition. The piezoelectric properties are sensitive to acceptor (Fe) modification in the PLZT system which was proved by the decreasing trend of piezoelectric charge coefficient (d 33) up to 3 mol% Fe and then increasing to 6 mol% Fe while the piezoelectric planar coupling coefficient (k p) showed a continuous decreasing trend throughout the series. Dielectric, ferroelectric and piezoelectric properties were characterized as a function of acceptor (Fe) concentration in the PLZT system for possible sensor and actuator applications. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of exchange–correlation potential on the plasmon dispersions in a doped symmetrical double quantum well
Authors: Şenadım Tüzemen E. , Turkoglu A. , Ergun Y. , Sokmen I. , Tanatar B.
Published: September 2006

We have calculated the plasmon dispersion relations in a doped double quantum well with and without exchange–correlation potential added to the effective potential of the system. The calculations were done for high and low doping densities by solving the Schrödinger and Poisson equations self‐consistently. Our numerical results show that the exchange–correlation potential is quite important at high doping densities of donor impurities for plasmon dispersions at large wave vectors. On the other hand, the ratio of subband populations ni to donor density ND is more affected at low densities. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic structure and physicochemical properties of selected penicillins
Authors: Soriano‐Correa Catalina , Sánchez Ruiz Juan F. , Raya A. , Esquivel Rodolfo O.
Published: September 2006

Traditionally, penicillins have been used as antibacterial agents due to their characteristics and widespread applications with few collateral effects, which have motivated several theoretical and experimental studies. Despite the latter, their mechanism of biological action has not been completely elucidated. We present a theoretical study at the Hartree–Fock and density functional theory (DFT) levels of theory of a selected group of penicillins such as the penicillin‐G, amoxicillin, ampicillin, dicloxacillin, and carbenicillin molecules, to systematically determine the electron structure of full β‐lactam antibiotics. Our results allow us to analyze the electronic properties of the pharmacophore group, the aminoacyl side‐chain, and the influence of the substituents (R and X) attached to the aminoacyl side‐chain at 6′ (in contrast with previous studies focused at the 3′ substituents), and to corroborate the results of previous studies performed at the semiempirical level, solely on the β‐lactam ring of penicillins. Besides, several density descriptors are determined with the purpose of analyzing their link to the antibacterial activity of these penicillin compounds. Our results for the atomic charges (fitted to the electrostatic potential), the bond orders, and several global reactivity descriptors, such as the dipole moments, ionization potential, hardness, and the electrophilicity index, led us to characterize: the active sites, the effect of the electron‐attracting substituent properties and their physicochemical features, which altogether, might be important to understand the biological activity of these type of molecules. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Characterization of typical chemical background interferences in atmospheric pressure ionization liquid chromatography‐mass spectrometry
Authors: Guo Xinghua , Bruins Andries P. , Covey Thomas R.
Published: September 2006

The structures and origins of typical chemical background noise ions in positive atmospheric pressure ionization liquid chromatography/mass spectrometry (API LC/MS) are investigated and summarized in this study. This was done by classifying chemical background ions using precursor and product ion scans on most abundant background ions to draw a family tree of the commonly occurring chemical background ions. The possible structures and the origins of the major chemical background noise are clearly revealed in the family trees. In agreement with some suggestions in the literature, the chemical background ions studied so far can be classified mainly as either ions of contaminants (or their degradation fragments) or cluster‐related ones. A significant contribution from the contaminants (airborne, from tubing and/or solvents) from plasticizer additives (phthalates, phenyl phosphates, sebacates and adipates, etc.) and silicones is concluded. These ions of contaminants can also serve as nuclei for the clustering of HPLC solvent or additives, such as water and acetic acid, thereby leading to a second family of background ions. This study explains the persistence of some chemical background noise even under fairly strong declustering conditions in API LC/MS. One of the other interesting conclusions is that there is a clear difference in structures between the chemical background ions and the protonated analytes generated under atmospheric pressure ionization. This conclusion will contribute to the on‐going research efforts to exclusively remove or reduce the interference of chemical background noise in API LC/MS. Copyright © 2006 John Wiley & Sons, Ltd.
Experimental evaluation of fishway modifications on the passage behaviour of adult Chinook salmon and steelhead at Lower Granite Dam, Snake River, USA
Authors: Naughton George P. , Caudill Christopher C. , Peery Christopher A. , Clabough Tami S. , Jepson Michael A. , Bjornn Theodore C. , Stuehrenberg Lowell C.
Published: September 2006

Previous studies of Pacific salmonid passage over Snake River dams indicated slowed passage at transition pools, the transition area between the fishway entrance and the fish ladder. In 2001 and 2002, we conducted an experiment to determine if modified weirs affected adult salmon and steelhead passage times and route selection through the Lower Granite Dam transition pool. Fish attraction flows through the lower ladder weirs were experimentally increased using removable panels. During the experiment we monitored radio‐tagged adult Chinook salmon and steelhead to determine passage routes and times through the transition pool. The weir treatment increased the number of spring–summer Chinook salmon passing straight through the transition pool compared to those exiting the transition pool to the collection channel or tailrace. Mean passage times through the transition pool differed among routes and were significantly lower during treatment periods for the exit‐to‐collection channel route in spring‐summer Chinook salmon, but not for other routes. Passage times among routes differed in steelhead, but there was no evidence of treatment effects on route use or passage time. Fall Chinook exhibited similar trends in route use and passage time to spring–summer Chinook, but differences were not significant, perhaps because of relatively small sample size. Total dam passage times did not differ by treatment or route for any run. Fish depth during passage of the transition pool suggested that most fish passed through submerged orifices and supported the hypothesis that increased water velocity through these orifices caused the increase in straight‐through passage in spring–summer Chinook. Collectively, the results suggested the weir modifications provided improvement to passage through the transition pool for spring–summer Chinook and no evidence of negative effects on other runs. The results from this study were used to develop new design criteria and modifications of the Lower Granite Dam fishway. Copyright © 2006 John Wiley & Sons, Ltd.
Bivariate random effect model using skew‐normal distribution with application to HIV‐RNA
Authors: Ghosh Pulak , Branco Marcia D. , Chakraborty Hrishikesh
Published: September 2006

Correlated data arise in a longitudinal studies from epidemiological and clinical research. Random effects models are commonly used to model correlated data. Mostly in the longitudinal data setting we assume that the random effects and within subject errors are normally distributed. However, the normality assumption may not always give robust results, particularly if the data exhibit skewness. In this paper, we develop a Bayesian approach to bivariate mixed model and relax the normality assumption by using a multivariate skew‐normal distribution. Specifically, we compare various potential models and illustrate the procedure using a real data set from HIV study. Copyright © 2006 John Wiley & Sons, Ltd.
TGF‐β/Smad‐signaling in liver cells: Target genes and inhibitors of two parallel pathways
Authors: Breitkopf Katja , Weng Honglei , Dooley Steven
Published: September 2006

Transforming growth factor (TGF)‐β is a major mediator of fibrosis in diverse organs/tissues, including liver, due to its gene regulatory properties that lead to high expression and secretion of extracellular matrix components. Whereas the canonical Smad pathway seems to be very simple, TGF‐β turns out to be a multiplicity factor with a highly cell type specific outcome and therefore, no universally valid plan of its signal transduction can be formulated. In the present review, we will summarize information about the Smad dependent and Smad independent TGF‐β signaling network in hepatic stellate cells (HSCs) and hepatocytes, with emphasis on its role in chronic liver disease. In addition, current state of the art anti‐TGF‐β strategies for liver fibrosis treatment are discussed.
Legislative Resources for the United States
Authors: Bird Ruth
Published: September 2006

Ruth Bird of the Bodleian Law Library identifies useful resources for US legislative research. The Bodleian Law Library (BLL) has extensive, current holdings of the majority of these resources in its collection, which are identified in the course of the paper. References to online locations for the titles and resources are also included.
Going Global, Acting Local: Multi-Site Management in US Law Firms
Authors: Maynard Linda
Published: September 2006

Over-paid, over-worked, and over here? From a trickle of firms arriving in the UK 50 years or so ago, US law firms are now a noisy presence in the London and wider European legal marketplace. They are expected by some estimates to commandeer 10% of the UK legal market within the next couple of years. Linda Maynard examines what it is like working in such a firm, in particular, looking at multi-site law firm management from the fringes rather than the centre.
Online Subscription Contract Checklist
Authors: Durrant Fiona
Published: September 2006

This is the latest article in our Checklist series and has been written by Fiona Durrant. It consists of a methodical list of questions to aid reading of a contract for an online subscription.
SLS/BIALL Academic Law Library Survey 2004/2005
Authors: Clinch Peter
Published: September 2006

This is the latest report analysing the results of the Society of Legal Scholars and BIALL Survey. It has been compiled by Peter Clinch, Information Specialist – Law, Cardiff University.
THE ORIGINS OF FEMINISM AND THE LIMITS OF ENLIGHTENMENT
Authors: BLOCH RUTH H.
Published: September 2006

The publication of the collection of essays Women, Gender and Enlightenment (ed. Sarah Knott and Barbara Taylor, Houndsmills: Palgrave MacMillan, 2005) affords an unusual opportunity to confront a myriad of interrelated issues, at once definitional and ideological, that face intellectual historians of seventeenth- and eighteenth-century Europe and America. The 768-page work came out of a highly unusual collaborative research project conducted from 1998 to 2001, “Feminism and Enlightenment, 1650–1850: A Comparative History,” a series of colloquia, conferences, and Internet exchanges enlisting the participation of over a hundred historians in Europe, North America, and Australia. The product of this extensive interaction showcases the contributions of thirty-eight authors, not only covering a broad array of topics but, still more remarkable, displaying a large degree of consensus about issues of interpretative concern. While dozens of books and articles have anticipated pieces of the arguments made in this volume, never has so extensive an attempt been made to pull them together into a cohesive whole.
THE CANVAS AND THE COLOR: TOCQUEVILLE'S “PHILOSOPHICAL HISTORY” AND WHY IT MATTERS NOW
Authors: KLOPPENBERG JAMES T.
Published: September 2006

In December of 1850, exhausted by his role in French politics and recuperating from tuberculosis, Alexis de Tocqueville retreated to the Amalfi coast to think, write, and recover. To his best friend Louis de Kergolay, Tocqueville wrote about completing his memoir on the 1848 revolution and his plans to undertake a comprehensive account of French history that would explain the turmoil of the past century. The appeal was powerful, he explained to Kergolay, but “the difficulties are immense. The one that most troubles my mind comes from the mixture of history properly so called with historical philosophy. I still do not see how to mix these two things,” he conceded, “and yet, they must be mixed, for one could say that the first is the canvas and the second the color, and that it is necessary to have both at the same time in order to do the picture.” Tocqueville feared “that the one is harmful to the other, and that I lack the infinite art that would be necessary in order to choose properly the facts that must, so to speak, support the ideas.
THE BEGINNING, THE MIDDLE AND THE END OF CLASSICAL MUSIC
Authors: SUSCHITZKY ANYA
Published: September 2006

Richard Taruskin, The Oxford History of Western Music, 6 vols. (Oxford and New York: Oxford University Press, 2005)

Until recently, serious students of music did not read sweeping histories of music. In a time of increasing specialization, we do not expect to find new ideas in such work. This has changed with the publication of Richard Taruskin's History of Western Music. Monumental in its scope and original in its approach but informal in its prose and always engagingly direct, it offers a provocative perspective on the whole of music's history and sets fresh agendas for anyone interested in music and its relation to the history of ideas, politics and culture. Taruskin's History differs from all previous projects of its kind in that it does not principally survey famous works by famous composers. Focusing instead on particular issues within a chronological framework (his chapter titles refer, amongst other things, to feudalism, humanism, enlightenment, virtuosos, transcendentalism and totalitarianism), and selecting composers whose music contributes to the consideration of those issues (sometimes omitting well-known figures or placing familiar works in radically new contexts), he sets out quite simply to explain why music has been composed as it has, and to show how its existence has relied not on composers in isolation but on a whole musical culture of composers, patrons, performers, critics and many others. Rather than relegating historical events and ideas to the status of context or calling them extra-musical, he places them at the centre of his narrative and in intricate dialogue with music; so while his close analyses of music will mean most to those with musical training, they are part of an argument about history that will be suggestive and illuminating to any reader.
IN MEMORIAM: KENNETH CMIEL
Authors: Hollinger David A.
Published: September 2006

“I am an American, Chicago born,” runs the first line of a famous novel by Saul Bellow. Anyone who knew the historian Kenneth Cmiel, who died on 4 February 2006, will recognize how this blunt affirmation of Chicago identity could serve Ken as well as it served Augie March. Not that Ken played the identity game pretentiously. A capacity to live a particular persona without being captured by it was one of his countless endearing traits. But being a Chicago person, by birth and by doctorate and by a style that never left him in Iowa City or Berkeley, meant a lot to Ken, and it gave a certain tone to his skeptical, yet sensitive, responses to the conceits and aspirations of his colleagues and friends.
Air concentrations of submerged and unsubmerged hydraulic jumps in a bedrock step‐pool channel
Authors: Vallé Brett L. , Pasternack Gregory B.
Published: September 2006

The classical hydraulic jump, which is a hydraulic jump formed in a horizontal, smooth, and prismatic laboratory flume, has often been used for estimating hydraulic and morphologic characteristics of mountain river channels. However, most studies utilizing classical hydraulic jump relationships have neglected the role of aerated flows and jump types prevalent in natural systems. By developing a methodology to survey, digitize, and visualize air concentrations for jumps in bedrock rivers, we present new data for submerged jumps and sloping jumps in a bedrock step‐pool channel. As with laboratory research, our results indicated peak, mean, and local air concentrations of natural jumps were skewed by submergence of the jump roller beneath the free surface. However, unlike laboratory research, cross‐stream variations were significant for both jumps, varying up to 20% across the jump width. Traces through each jump thalweg also indicated the classical hydraulic jump was a poor analogue for estimating surficial air concentrations.
Origin and geochemical evolution of the Madeira‐Tore Rise (eastern North Atlantic)
Authors: Geldmacher Jörg , Hoernle Kaj , Klügel Andreas , Bogaard Paul v. d. , Wombacher Frank , Berning Björn
Published: September 2006

The Madeira‐Tore Rise, located ∼700 km off the NW African coast, forms a prominent ridge in the east Atlantic. The age and origin of the rise are controversial. This study presents major and trace element, Sr, Nd, Pb, Hf isotope and 40Ar/39Ar age determinations from volcanic rocks dredged from different sites along the rise. In addition, isotopic compositions of rock samples from Great Meteor Seamount in the central Atlantic are presented. The new radiometric and paleontologically constrained ages identify two major episodes of volcanism: The first is the base of the rise (circa 80 to >95 Ma) and the second is seamounts on the rise (0.5–16 Ma). It is proposed that interaction of the Canary hot spot with the Mid‐Atlantic spreading center formed the deep basement of the Madeira‐Tore Rise and the J‐Anomaly Ridge west of the Atlantic spreading center in the Mid‐Cretaceous. Age and geochemical data and plate tectonic reconstructions suggest, however, that the recovered Late Cretaceous volcanic rocks represent late stage volcanism from the time when the Madeira‐Tore Rise was still close to the Canary hot spot. Long after moving away from the influence of the Canary hot spot, the Madeira‐Tore Rise was overprinted by late Cenozoic volcanism. Miocene to Pleistocene volcanism at the northern end of the rise can be best explained by decompression mantle melting beneath extensional sectors of the Azores‐Gibraltar Fracture Zone (African‐Eurasian plate boundary). The geochemical compositions of these volcanic rocks suggest that the magmas were variably contaminated by enriched material within or derived by melting of enriched material underplated at the base of the lithosphere, possibly originating from the Cretaceous Canary plume. Alternatively, these late Cenozoic volcanic rocks may have derived from decompression melting of enriched pyroxenitic/eclogitic material in the upper mantle. Isotopically more depleted Pliocene to Pleistocene volcanism at the southern end of the Madeira‐Tore Rise may be related to the nearby Madeira hot spot.
Temporal variation of aerosol properties at a rural continental site and study of aerosol evolution through growth law analysis
Authors: Wang Jian , Collins Don , Covert David , Elleman Robert , Ferrare Richard A. , Gasparini Roberto , Jonsson Haflidi , Ogren John , Sheridan Patrick , Tsay Si‐Chee
Published: September 2006

Aerosol size distributions were measured by a Scanning Mobility Particle Sizer (SMPS) on board the CIRPAS Twin Otter aircraft during 16 flights at the Southern Great Plains (SGP) site in northern central Oklahoma as part of the Aerosol Intensive Operation period in May 2003. During the same period a second SMPS was deployed at a surface station and provided continuous measurements. Combined with trace gas measurements at the SGP site and back trajectory analysis, the aerosol size distributions provided insights into the sources of aerosols observed at the SGP site. High particle concentrations, observed mostly during daytime, were well correlated with the sulfur dioxide (SO2) mixing ratios, suggesting nucleation involving sulfuric acid is likely the main source of newly formed particles at the SGP. Aerosols within plumes originating from wildfires in Central America were measured at the surface site. Vertically compact aerosol layers, which can be traced back to forest fires in East Asia, were intercepted at altitudes over 3000 m. Analyses of size‐dependent particle growth rates for four periods during which high cloud coverage was observed indicate growth dominated by volume controlled reactions. Sulfate accounts for 50% to 72% of the increase in aerosol volume concentration; the rest of the volume concentration increase was likely due to secondary organic species. The growth law analyses and meteorological conditions indicate that the sulfate was produced mainly through aqueous oxidation of SO2 in clouds droplets and hydrated aerosol particles.
Global influence of the Northern Hemisphere second mode of the zonal average of the zonal wind
Authors: Song Jie , Zhou Wen , Pan Jing , Li Chongyin
Published: September 2006

The authors examine the impact of two zonal wind modes in the northern hemisphere (Northern Annular Mode, NAM, and the second zonal wind mode) on the global domain during the normal (non‐El Niño/Southern Oscillation, ENSO) northern winter from 1981–2002. It is found that both modes are in association with tropical zonal wind anomalies, but only the second zonal wind mode has significant linkage with the Southern Annular Mode (SAM), particularly leading about 6–19 days. This kind of linkage can also be found in extended datasets but only evident since 1974.
Consumer Trust in Internet Shopping in Ireland: Towards the Development of a More Effective Trust Measurement Instrument
Authors: Connolly Regina , Bannister Frank
Published: September 2006

Trust is a complex phenomenon that pervades human relations. It is essential for the success of business-to-consumer electronic commerce, where many of the tools that can be used in its absence (contracts, advance payments, insurance, etc.) may not be available. However, research as to how consumer trust can be built in an online environment is limited and varies considerably in terms of the dimensions of the problem that are examined. Consequently, much of our understanding of the antecedents of trust in online shopping context remains fragmented. This study uses a previously validated measurement instrument to investigate, in an Irish context, the existence and importance of specific perceptions and factors that are thought to predict the generation of consumer trust in Internet shopping. The research results provide evidence that Irish consumers’ perception of vendor trustworthiness is the result of specific factors that it is possible for vendors to manage. A modified model that addresses the key dimensions of consumer trust in Internet shopping in Ireland is proposed.
The Urban Creative-Food Economy: Producing Food for the Urban Elite or Social Inclusion Opportunity?
Authors: Donald Betsy , Blay-Palmer Alison
Published: September 2006

The food industry has always been a major generator of economic activity in the Greater Toronto Area. However, recently the innovative and creative elements of the industry have changed. Since the mid-1990s, the fastest growing segment within the industry has been small and medium-sized enterprises (SMEs). The specialty, ethnic, and organic SMEs (hereinafter referred to as the ‘creative-food’ industry) appear to be particularly innovative as they respond to consumer demand for local, fresh, ethnic, and fusion cuisine. On the basis of sixty-five interviews with food producers, processors, restaurateurs, food media, non-government organizations, government, and private sector agencies, it is suggested that this creative-food sector is thriving despite existing public policies that bias toward large-scale, industrialized agri-food firms in the region. As such, a disconnect currently exists between, on the one hand, the traditional agrifood paradigm that the government regulatory environment is promoting and, on the other hand, the locally consumer-driven food cluster that is emerging. Public policies of multiculturalism and education have done more to facilitate the unprecedented growth of this creative subcomponent of the food sector than have explicit public food-policy initiatives. However, there is still room for policy initiatives that advance the development of this dynamic sector, especially in the area of supportive infrastructure, access to health-based ethnically appropriate food, food education, and fair labour standards. Contrary to a widely held view, the creative-food industry is not just about promoting exclusive foods for the pleasure of urban elite. Rather, it offers an opportunity for a more socially inclusive and sustainable urban development model. The findings also have implications for multilevel governance in cluster formation and policy, future research on food, as well as for theories on innovation, urban creativity, and governance.
Quorum signal molecules as biosurfactants affecting swarming in
Rhizobium etli
Authors: Daniels Ruth , Reynaert Sven , Hoekstra Hans , Verreth Christel , Janssens Joost , Braeken Kristien , Fauvart Maarten , Beullens Serge , Heusdens Christophe , Lambrichts Ivo , De Vos Dirk E. , Vanderleyden Jos , Vermant Jan , Michiels Jan
Published: September 2006

Swarming motility is suggested to be a social phenomenon that enables groups of bacteria to coordinately and rapidly move atop solid surfaces. This multicellular behavior, during which the apparently organized bacterial populations are embedded in an extracellular slime layer, has previously been linked with biofilm formation and virulence. Many population density-controlled activities involve the activation of complex signaling pathways using small diffusible molecules, also known as autoinducers. In Gram-negative bacteria, quorum sensing (QS) is achieved primarily by means of
N
-acylhomoserine lactones (AHLs). Here, we report on a dual function of AHL molecules in controlling swarming behavior of
Rhizobium etli
, the bacterial symbiotic partner of the common bean plant. The major swarming regulator of
R. etli
is the
cinIR
QS system, which is specifically activated in swarming cells by its cognate AHL and other long-chain AHLs. This signaling role of long-chain AHLs is required for high-level expression of the
cin
and
rai
QS systems. Besides this signaling function, the long-chain AHLs also have a direct role in surface movement of swarmer cells as these molecules possess significant surface activity and induce liquid flows, known as Marangoni flows, as a result of gradients in surface tension at biologically relevant concentrations. These results point to an as-yet-undisclosed direct role of long-chain AHL molecules as biosurfactants.
A Trojan horse transition state analogue generated by MgF
3
−
formation in an enzyme active site
Authors: Baxter Nicola J. , Olguin Luis F. , Goličnik Marko , Feng Guoqiang , Hounslow Andrea M. , Bermel Wolfgang , Blackburn G. Michael , Hollfelder Florian , Waltho Jonathan P. , Williams Nicholas H.
Published: September 2006

Identifying how enzymes stabilize high-energy species along the reaction pathway is central to explaining their enormous rate acceleration. β-Phosphoglucomutase catalyses the isomerization of β-glucose-1-phosphate to β-glucose-6-phosphate and appeared to be unique in its ability to stabilize a high-energy pentacoordinate phosphorane intermediate sufficiently to be directly observable in the enzyme active site. Using
19
F-NMR and kinetic analysis, we report that the complex that forms is not the postulated high-energy reaction intermediate, but a deceptively similar transition state analogue in which MgF
3
−
mimics the transferring PO
3
−
moiety. Here we present a detailed characterization of the metal ion–fluoride complex bound to the enzyme active site in solution, which reveals the molecular mechanism for fluoride inhibition of β-phosphoglucomutase. This NMR methodology has a general application in identifying specific interactions between fluoride complexes and proteins and resolving structural assignments that are indistinguishable by x-ray crystallography.
An extensive repertoire of type III secretion effectors in
Escherichia coli
O157 and the role of lambdoid phages in their dissemination
Authors: Tobe Toru , Beatson Scott A. , Taniguchi Hisaaki , Abe Hiroyuki , Bailey Christopher M. , Fivian Amanda , Younis Rasha , Matthews Sophie , Marches Olivier , Frankel Gad , Hayashi Tetsuya , Pallen Mark J.
Published: September 2006

Several pathogenic strains of
Escherichia coli
exploit type III secretion to inject “effector proteins” into human cells, which then subvert eukaryotic cell biology to the bacterium's advantage. We have exploited bioinformatics and experimental approaches to establish that the effector repertoire in the Sakai strain of enterohemorrhagic
E. coli
(EHEC) O157:H7 is much larger than previously thought. Homology searches led to the identification of >60 putative effector genes. Thirteen of these were judged to be likely pseudogenes, whereas 49 were judged to be potentially functional. In total, 39 proteins were confirmed experimentally as effectors: 31 through proteomics and 28 through translocation assays. At the protein level, the EHEC effector sequences fall into >20 families. The largest family, the NleG family, contains 14 members in the Sakai strain alone. EHEC also harbors functional homologs of effectors from plant pathogens (HopPtoH, HopW, AvrA) and from
Shigella
(OspD, OspE, OspG), and two additional members of the Map/IpgB family. Genes encoding proven or predicted effectors occur in >20 exchangeable effector loci scattered throughout the chromosome. Crucially, the majority of functional effector genes are encoded by nine exchangeable effector loci that lie within lambdoid prophages. Thus, type III secretion in
E. coli
is linked to a vast phage “metagenome,” acting as a crucible for the evolution of pathogenicity.
S100A4 accelerates tumorigenesis and invasion of human prostate cancer through the transcriptional regulation of matrix metalloproteinase 9
Authors: Saleem Mohammad , Kweon Mee-Hyang , Johnson Jeremy James , Adhami Vaqar Mustafa , Elcheva Irina , Khan Naghma , Bin Hafeez Bilal , Bhat Kumar M. R. , Sarfaraz Sami , Reagan-Shaw Shannon , Spiegelman Vladimir S. , Setaluri Vijayasaradhi , Mukhtar Hasan
Published: September 2006

We previously showed that the calcium-binding protein S100A4 is overexpressed during the progression of prostate cancer (CaP) in humans and in the TRAMP (transgenic adenocarcinoma of the mouse prostate) mouse model. We tested a hypothesis that the S100A4 gene plays a role in the invasiveness of human CaP and may be associated with its metastatic spread. We observed that siRNA-mediated suppression of the S100A4 gene significantly reduced the proliferative and invasive capability of the highly invasive CaP cells PC-3. We evaluated the mechanism through which the S100A4 gene controls invasiveness of cells by using a macroarray containing 96 well characterized metastatic genes. We found that matrix metalloproteinase 9 (MMP-9) and its tissue inhibitor (TIMP-1) were highly responsive to S100A4 gene suppression. Furthermore, S100A4 suppression significantly reduced the expression and proteolytic activity of MMP-9. By employing an MMP-9-promoter reporter, we observed a significant reduction in the transcriptional activation of the MMP-9 gene in S100A4-siRNA-transfected cells. Cells overexpressing the S100A4 gene (when transfected with pcDNA3.1-S100A4 plasmid) also significantly expressed MMP-9 and TIMP-1 genes with increased proteolytic activity of MMP-9 concomitant to increased transcriptional activation of the MMP-9 gene. S100A4-siRNA-transfected cells exhibited a reduced rate of tumor growth underin vivoconditions. Our data demonstrate that the S100A4 gene controls the invasive potential of human CaP cells through regulation of MMP-9 and that this association may contribute to metastasis of CaP cells. We suggest that S100A4 could be used as a biomarker for CaP progression and a novel therapeutic or chemopreventive target for human CaP treatment.
The Era of Sadat
Authors: Kenney Jeffrey T.
Published: September 2006

This chapter covers the political discourse on Islamist extremism during the Sadat years. Sadat established his reputation as president by steering a course away from the policies of his predecessor. His distinctive legacy was his economic and political opening to the West, which was preceded by an opening up of Egyptian society. Discourse on extremism during this period bears the distinct markings of the political negotiations underway between Islamists and the state; and the Kharijites were a tool for the claims of both the authorities and Islamists.
Introduction
Authors: Kenney Jeffrey T.
Published: September 2006

This introductory chapter begins with a study of the mythical image of the Kharijites created by medieval thinkers in the context of the political and cultural world of mid-20th-century Egypt. It explains the relevance of Islam's mythic history, including the Kharijites, to the development of modern Egypt. It argues that reinvented Kharijism in Egypt has, at different times, fitted the assessments offered by both proponents and critics. An overview of the succeeding chapters is presented.
The Child‐Scientist Theory
Authors: Goldman Alvin I.
Published: September 2006

Early childhood failures on false-belief tasks and related tasks lead many developmental psychologists to conclude that children (like scientists) undergo a succession of changes in their mental-state theories, especially changes from a non-representational to a representational theory. Early errors in belief attribution are viewed as the product of a “conceptual deficit” rather than performance limitations. Other evidence, however, suggests that performance factors like memory and inhibitory control problems are at least partly responsible. Recent experiments with reduced task demands enabled children as young as 15 months to show understanding of false belief. Child-scientist advocates usually hold that theoretical inference is used for both first-person and third-person mindreading, but there is evidence that undercuts first-person/third-person parallelism.
Simulation in Low‐Level Mindreading
Authors: Goldman Alvin I.
Published: September 2006

People have a primitive and largely automatic ability to recognize emotions in faces, an ability best explained by simulation, more specifically, mirror processes. In lesion studies of fear, disgust, and anger, paired selective deficits have been found in experiencing and recognizing these emotions. A patient with insula and basal ganglia damage, for example, scored very low on a questionnaire for experiencing disgust and was also significantly and selectively impaired in recognizing disgust in facial expressions. Such findings are best explained by simulation theory, which predicts that damage to a neural system responsible for undergoing a certain emotion would also yield impairment in recognizing it. Mirror processes involve matching neural activation in both a subject and an observer of a specific mental state, and such processes have been identified (via single cell recordings and neuroimaging studies) for motor intention, touch, pain, and the several emotions listed above.
Honest Patriots
Authors: Shriver Donald W.
Published: September 2006

The book records attempts in three countries — Germany, South Africa, and the United States — to educate patriots who are neither loveless critics nor uncritical lovers of their nation, but rather loving critics. How does a national public learn to acknowledge the “dark side” of their country’s history? In the post-1945 years, Germans slowly but surely came to pay public attention to the evils of the Nazi era. In an astonishing accumulation of memorials, museums, films, anniversaries, and high school history books, the country has put its future generations on notice: “Never again”. Post-apartheid South Africa has seen comparable developments, especially in its Truth and Reconciliation Commission, new Constitution, memorials, and radically revised school text books. The United States, with a culture more focused on the future than the past, is undergoing a similar but slower public process. Two great crimes mark its national past: slavery and the fate of the people called Indians. The US is beginning to confront these collective crimes with new realism in new laws, museums, films, memorials, and history books. A political culture grows in its capacity for justice by remembering injustice. For a people not to remember the misdeeds of their past is to risk repeating them. Public memory requires concrete public signs, rituals, memorials, and education. This book seeks to record the attempts of these three countries to give public expression to justice by remembering injustice.
Germany Remembers
Authors: Shriver, Jr. Donald W.
Published: September 2006

Foreigners still wonder if Germans can really be trusted to remember the evils of Nazism. This chapter documents the array of public measures which the country has taken in the past 60 years to educate its upcoming generations of citizens about those evils, with the hope, “Never again”. Documented here are the Holocaust memorials, anniversaries, museums, and school texts that have qualified Germany now as having established a “culture of memory” with few equals elsewhere in the world.
South Africa
Authors: Shriver, Jr. Donald W.
Published: September 2006

South Africa is credited with having achieved one of the great historical non-violent transitions from oppression to democracy. In the 10 years after 1994, its citizens and government have enacted several measures for ensuring that future generations will neither forget the apartheid past nor ever repeat it: new laws, a new constitution, a Truth and Reconciliation Commission, museums, liberation anniversaries, and public memorials to human suffering in the past. This chapter pays special attention to the TRC of 1995-98 and lessons to be learned from its work by other countries.
Old Unpaid Debt
Authors: Shriver, Jr. Donald W.
Published: September 2006

Americans live in a culture resistant to much talk about the evils in their past; they prefer to think about the future. But like the descendants of victims of evil in Germany and South Africa, some living Americans are not about to forget the evil past. Prominent among them are African Americans. This chapter explores the stubborn persistence of racism in America, the work of a growing number of citizens to remember the pains of racism past and present, and to express that memory in public ways. Local illustrations of public repentance include Richmond, Virginia; Rosewood, Florida; Tulsa, Oklahoma; Salem, Oregon; and Selma, Alabama. After a “tour” of high school history books of 1960-2000, the chapter ends with some summary answers to the question, “Can the past be repaired?” as well as arguments for and against reparations for slavery.
Unreflected Absences
Authors: Shriver, Jr. Donald W.
Published: September 2006

So many “Indians” died in the onslaughts of European colonization, so many were diverted to reservations, and so little attention is paid Indian history in public schools that Americans generally are profoundly ignorant of who Indians were and are. This chapter documents some hopeful changes in this public cultural ignorance during the past thirty years: museums, films, history writing, high school history teaching, apologies, reparations, and memorials that promise some increase in public acknowledgment of the Indian claim, “We were here, and we still are here”. The author describes his own pilgrimage of learning about the original Powhatan nation of his native Virginia and the Mohicans of New York. The chapter ends with a survey of legal changes that have accorded new political power to members of the 550 surviving Indian nations, along with continuing legal and ethical tensions in the relation of two million Indians to the rest of the country.
Being Human While Being American
Authors: Shriver, Jr. Donald W.
Published: September 2006

This chapter celebrates public occasions and measures in recent years where the American government and citizens’ groups acknowledged national “misdeeds” in international relations, especially in its wars. The chapter begins with the 1998 Pentagon award of three soldiers’ medals to the helicopter crewmen who sought to call the My Lai massacre to a halt. It then describes recent presidential apologies for American failures to curb massacres in Bosnia and Rwanda. The author then nominates some still-to-be-acknowledged occasions for repentance in this country’s recent international affairs: the civilian-bombings of World War II, failures of public leaders to mourn — or even to count — the deaths of enemies in war, and the arrogance of American claims to global “full spectrum dominance”. The chapter concludes with pleas that America listen more carefully to its friendly critics in other countries, especially the two countries with which the book began: Germany and South Africa.
Moral Disagreement
Authors: Gert Bernard , Culver Charles M. , Clouser K. Danner
Published: September 2006

This chapter challenges the view that every moral question has a unique correct answer. The sources of unresolvable moral disagreement are the following four differences: (1) in the rankings of the goods (benefits) and evils (harms); (2) in estimates of the consequences of everyone knowing that violation of a moral rule is allowed in these circumstances; (3) in the interpretation of a moral rule; and (4) about who is protected by the moral rules. Important questions that do not have a unique correct answer are those concerning the best health care delivery system and the moral acceptability of abortion.
Principlism
Authors: Gert Bernard , Culver Charles M. , Clouser K. Danner
Published: September 2006

This chapter compares an account of common morality with the account of morality presented by Beauchamp and Childress in their book, The Principles of Biomedical Ethics. It offers a general critique of principlism, as well as of the first three of their four principles: autonomy, beneficence, nonmaleficence, and justice. It shows the superiority of the account of morality as an informal public system over their account, which uses four freestanding principles not embedded in any system.
What Doctors Must Know about Medical Practice
Authors: Gert Bernard , Culver Charles M. , Clouser K. Danner
Published: September 2006

This chapter shows the importance of recognizing the probabilistic nature of medical diagnosis and treatment. It discusses the possibly serious effects of physicians not understanding Bayes theorem, and hence, not appreciating the importance of knowing the prevalence of a disorder in the population to be treated or screened. It shows the importance of doctors knowing about volume-outcome studies, geographical variation studies, and practice guidelines.
INTRODUCTION
Authors: Code Lorraine
Published: September 2006

Proposing that ecological thinking can effect a revolution in philosophy comparable to Kant’s Copernican revolution, the introduction eschews the abstraction and reductivism of orthodox western epistemology, to relocate inquiry “down on the ground”, in everyday lives and situations. In a series of ecological cautionary tales which display the negative effects of epistemologies of mastery, the introduction argues for mining the untapped resources ecological thinking affords, while warning against ecology’s propensity to romanticize “nature” and to align women and other Others with nature thus romanticized. It indicates why this book cannot be identified as an eco-feminist text, despite productive alliances between ecological thinkers and eco-feminists.
ECOLOGICAL THINKING
Authors: Code Lorraine
Published: September 2006

This chapter shows how ecology, literally and metaphorically, affords a model for rethinking the established theories of knowledge, and relations between humanity and the other-than-human, that characterize the social imaginary of the post-Enlightenment western world. Ecology figures as a study of habitats where people can live well together; of the ethos and habitus enacted in the customs, social organizations, and creative-regulative principles by which they strive or fail to achieve this end. Focusing on a shift in Rachel Carson’s thinking from geographical to ecological, and drawing on Kristin Shrader-Frechette’s analysis of ecological science, the chapter draws a parallel between Carson’s tacit epistemology and that of biologist Karen Messing to develop the working conception of ecology that informs the argument of the book. A reclamation of testimony as a source of evidence is central to the argument.