bluuebunny/crossref_metadata_2025 huggingface dataset:
Bimodal actions of reactive oxygen species in the differentiation and bone‐resorbing functions of osteoclasts
Authors: Kim Hyunsoo , Kim Ick Young , Lee Soo Young , Jeong Daewon
Published: September 2006

In order to demonstrate that cellular redox status undergoes decreased reduction during osteoclast differentiation and further decreased reduction during osteoclastic bone resorption, we analyzed γ‐glutamylcysteinyl synthetase activity, a glutathione synthesis rate‐limiting enzyme, and total glutathione and thiol groups. Moderate and severe redox shifts towards a more oxidizing environment induced gradual increases and decreases in osteoclastogenesis. Moreover, while severe glutathione depletion inhibited bone resorption, moderate glutathione repletion enhanced bone resorption. In summary, our observations suggest that there is a threshold for redox status, representing biphasic patterns in osteoclast differentiation and function.
The dynamics of autocratic coercion after the Cold War
Authors: Way Lucan A. , Levitsky Steven
Published: September 2006

This article examines coercive capacity and its impact on autocratic regime stability in the context of post-Soviet Armenia, Belarus, Georgia, and Ukraine. In the post-Cold War era, different types of coercive acts require different types of state power. First, high intensity and risky measures – such as firing on large crowds or stealing elections – necessitate high degrees of cohesion or compliance within the state apparatus. Second, effective low intensity measures – including the surveillance and infiltration of opposition, and various forms of less visible police harassment – require extensive state scope or a well-trained state apparatus that penetrates large parts of society.

Coercive state capacity, rooted in cohesion and scope, has often been more important than opposition strength in determining whether autocrats fall or remain in power. Thus, the regime in Armenia that was backed by a highly cohesive state with extensive scope was able to maintain power in the face of highly mobilized opposition challenges. By contrast, regimes in Georgia where the state lacked cohesion and scope fell in the face of even weakly mobilized opposition. Relatively high scope but only moderate cohesion in Belarus and Ukraine has made autocratic regimes in these countries generally more effective at low intensity coercion to prevent the emergence of opposition than at high intensity coercion necessary to face down serious opposition challenges.
La revendication du titre “indien” par les Métis du Manitoba, 1860–1870
Authors: O'Toole Darren
Published: September 2006

Résumé.Après plus de deux décennies, un tribunal manitobain a fixé une date pour entendre l'affaireFMMqui touche à la concession des terres aux Métis selon l'art. 31 de laLoi de 1870 sur le Manitoba. Le politologue Thomas Flanagan répète inlassablement que les Métis ne se sontjamaisdécrits comme peuple aborigène ayant des droits fonciers spéciaux pendant la résistance de 1869–70. Puisqu'il est fort probable que la Couronne se serve encore une fois de la recherche de Flanagan dans l'affaireFMM, le moment est opportun pour réexaminer les arguments de Flanagan. Dans ce but, l'auteur examine ici de plus près certaines des prétentions de Flanagan, notamment celles qui veulent que : 1) les Métis n'aientjamaisrevendiqué le statut de peuple autochtone ou des droits autochtones pendant les événements de 1869–70; 2) les listes de droits ne contiennent aucune référence aux droits aborigènes des Métis; et 3) l'abbé Ritchot i) n'ait eu aucun mandat de négocier l'extinction du titre aborigène des Métis et une concession de terres; ii) n'ait été qu'un délégué parmi trois.

Abstract.After more than two decades, a Manitoban court has set a date to hear of theMMFcase which touches on the Métis land grant in s. 31 of theManitoba Act, 1870. Political scientist Thomas Flanagan has continually repeated that the Métisneverdescribed themselves as an Aboriginal people with special land rights during the resistance of 1869–70. As it is quite probable that the Crown will use Flanagan's research in theMMFcase, it is timely to reexamine it. To this end, the author takes a closer look at some of Flanagan's conclusions, most notably those that claim that: 1) the Métisneverclaimed status as an Aboriginal people during the events of 1869–70; 2) the various Bills of Rights contain no reference to the aboriginal rights of the Métis; 3) the abbot Ritchot : i) had no mandate to negotiate the extinction of Métis aboriginal rights and a land grant; ii) was but one of three delegates.
The Forging of Institutional Autonomy: A Comparative Study of Electoral Management Commissions in Africa
Authors: Gazibo Mamoudou
Published: September 2006

Abstract.Building upon the theoretical framework of new-institutionalism, this article concentrates on electoral management commissions (EMCs), which, though theraison d'êtreof political battles in many African countries, have attracted very little analysis in academic literature. The sample includes seven countries and I concentrate on the issue of forging institutional autonomy. I propose five modes of institutional forging that produce different levels of autonomy. At the same time, I argue that autonomy refers less to legal provisions than to the empiricalself-reinforcingandlock-inprocesses, which may or may not take place depending onpower relationsin the political arena. In turn, however, these differences may explain the contrasting trajectories African states have takenvis-à-visdemocratization.

Résumé.Alors qu'elles sont au cœur des luttes politiques dans plusieurs pays africains, les commissions électorales sont peu étudiées dans la littérature sur la démocratisation. Cet article utilise un cadre théorique néo-institutionnel pour analyser les commissions de sept pays en se concentrant spécifiquement sur la question de l'autonomie institutionnelle. Il met à jour cinq modes de création institutionnelle correspondant à différents niveaux d'autonomie qui, en retour, expliquent les trajectoires divergentes des pays en matière de démocratisation. L'autonomie est à rechercher moins dans les prérogatives juridiques que dans les rapports de forces entre acteurs au moment de l'émergence de l'institution et dans les processus subséquents d'autoreproduction institutionnelle.
Quebec: State and Society, 3rd Edition
Authors: Hayday Matthew
Published: September 2006

Quebec: State and Society, 3rdEdition, Alain-G. Gagnon, ed., Peterborough: Broadview Press,
2004, pp. 500.

Alain-G. Gagnon's compilation Quebec: State and Society
has been a very popular staple of political science course syllabi over
the past two decades. Now in its third edition, Gagnon has compiled a
selection of twenty-two original articles by leading scholars in the
social sciences to examine the diverse facets of modern Quebec society and
politics. English-speaking students will benefit greatly from the fact
that fifteen of the essays have been translated from the original French,
which will broaden their exposure to top-level francophone scholarship
(although in some cases the translation is imprecise and contains a number
of Gallicisms). This collection includes some extremely strong
contributions, and a diverse array of perspectives on modern Quebec. Yet
in other respects, particularly in terms of the overall structure of the
book, it suffers from some serious weaknesses that might make it of
questionable suitability for teaching purposes.
Les systèmes électoraux et les modes de scrutin,
3e édition
Authors: Dubé Sébastien
Published: September 2006

Les systèmes électoraux et les modes de scrutin,
3eédition, Pierre Martin, Paris
: Montchrestien, 2006, 156 pages.

Dans la troisième édition de son ouvrage Les
systèmes électoraux et les modes de scrutin, Pierre
Martin avance deux idées principales. La première est que
les modes de scrutin sont les produits des systèmes politiques
“ et vice versa ” (p. 10). Par cette position, l'auteur
rejette le déterminisme sous-jacent à certaines
études sur les modes de scrutin qui tendent à “
surestimer leur effet ” (p. 135). Après tout, analyse-t-il,
“ [l]eur influence sur la structuration des
systèmes partisans et la répartition des votes des
électeurs entre les partis est faible et absolument pas
décisive. ” La deuxième idée,
complémentaire de la précédente, soutient que “
les systèmes partisans résultent principalement de
l'influence de la sociologie et de l'histoire ” (p.
113).
Political Writings
Authors: Wright Joanne H.
Published: September 2006

Political Writings, Margaret Cavendish (Susan James, ed.),
New York: Cambridge University Press, 2003, pp. xxxix, 298.

The publication of Margaret Cavendish's Political
Writings is part of a recent effort to make Cavendish's
seventeenth-century works more accessible to students and scholars alike.
Political Writings is a particularly significant addition to this
effort in that it contains two of Cavendish's most explicitly
political texts, A Description of a New World called the Blazing
World (1666), Cavendish's best-known endeavour in utopian
fiction, along with the first modern edition of Orations of Divers
Sorts (1662). Combined with a concise introduction by the
volume's editor, philosopher Susan James, who expertly navigates
Cavendish's many influences and references—ancient and
modern—the book effectively puts Cavendish on the map as a political
thinker. Although the most published Englishwoman of her period, and now
the subject of a veritable growth industry in the fields of early modern
literary and gender history, Margaret Cavendish has received virtually no
attention in the field of political thought. With her inclusion in the
Cambridge Texts in the History of Political Thought series, there is hope
that Cavendish will now be treated and analyzed, not just as the prolific
writer of drama, poetry and natural philosophy that she was, but as an
incisive thinker who engaged with, and published on, the most vital
political questions facing Civil War and Restoration England.
La démocratie : histoire des idées.
Authors: Breaugh Martin
Published: September 2006

La démocratie : histoire des idées., Boris
DeWiel, Québec : Les Presses de l'Université Laval,
coll. Zêtêsis, 2005, 270p.

“ Ensemble de procédures ”, “ régime
” au sens large du terme, forme de “ sociabilité
humaine ”: la nature de la démocratie demeure l'objet
d'une discussion théorique et pratique d'une importance
primordiale, car il s'agit d'élucider les tenants et les
aboutissants de cet “ horizon indépassable ” de la
politique contemporaine qu'est la démocratie. La
démocratie: histoire des idées s'inscrit
précisément dans ce débat portant sur la nature et
les finalités de la démocratie. Sous couvert d'une
reconstitution intellectuelle de ses principaux enjeux, Boris DeWiel
procède à un plaidoyer en faveur d'une conception de la
démocratie en tant que régime qui accueille le conflit
insoluble des valeurs. S'inscrivant explicitement dans la mouvance
issue de la pensée d'Isaiah Berlin, l'auteur soutient
qu'une compréhension véritable de la démocratie
passe par une reconnaissance du “ pluralisme des valeurs ”,
entendu comme “ la théorie embarrassante selon laquelle le
bien n'est pas monolithique, nos intérêts communs
entrent en conflit les uns avec les autres et, quand ils finissent par se
heurter mutuellement, il n'y a plus de réponses universelles
” (2).
The press and the palace: the two-way relationship between Abdülhamid II and the press, 1876–1908
Authors: BOYAR EBRU
Published: September 2006

While Abdülhamid is usually represented as an extreme example of a ‘censorship sultan’, this article seeks to redress the balance and to present a more nuanced picture of Abdülhamid's relationship with the press. Based largely on archival material from Istanbul, the article investigates how press magnates sought to use their relationship with the palace in order to ensure their survival and to gain the concessions they wanted, and how, in turn, the sultan manipulated the press and used it to cultivate his own image and to present the empire and his sultanate in the way he wished, both to his own subjects and to other states outside the Ottoman frontier.
Managing external risks to health technology assessment programs
Authors: Hailey David , Juzwishin Don
Published: September 2006

Objectives: The aim of this study was to develop a guide to identifying and managing risks for health technology assessment (HTA) programs and to obtain opinions on this topic from HTA agencies.

Methods: The risks and approaches to their management were compiled, drawing on experiences from HTA programs and the risk assessment literature. Opinion on this classification was obtained from members of the International Network of Agencies for Health Technology Assessment (INAHTA).

Results: Twenty-one risks for HTA programs were identified under the categories Formulation of HTA Questions, Preparation of the HTA Product, Dissemination, and Contracting. For each risk area, potential consequences and suggested management approaches were outlined. Responses from ten HTA programs indicated substantial agreement regarding the risks that had been identified and on the importance of risk management for their own operations.

Conclusions: Prudent management of HTA programs should take into account the risks related to external factors.
Disseminating evidence from health technology assessment: The case of tobacco prevention
Authors: Axelsson Susanna , Helgason Ásgeir R. , Lund Karl E. , Adolfsson Jan
Published: September 2006

Objectives: The aims of the present study were to investigate the awareness among dentists and dental hygienists of evidence-based reports and guidelines on tobacco cessation activities and the impact these publications had on clinical practice.

Methods: A questionnaire was mailed to dental hygienists and dentists in Stockholm County, Sweden, and the results were compared with a previous investigation.

Results: Among the respondents, awareness of a popular science version of a systematic review on smoking and its effect on oral health was reported by 90 percent of the hygienists and 66 percent of the dentists. The information was used in clinical work by 34 percent of the dentists and 54 percent of the hygienists. Reported changes in patterns of practice were more frequent recommendations to use nicotine replacement therapy and a more widespread use of setting quit dates. Approximately one quarter of the dental professionals reported that they had increased tobacco cessation consultation because of the results from the reports.

Conclusions: Changes in patterns of practice were observed after dissemination of evidence-based information on tobacco cessation. Methods that were proven to be effective in the evidence-based report such as discussing quit dates and recommending nicotine replacement therapy were more commonly used after the publication of the report. Short, popular versions of extensive systematic reviews seem to be useful for implementing evidence-based knowledge and changing clinical practice.
Quantification Problems in Depth Profiling of PWR Steels Using
Ar+ Ion Sputtering and XPS Analysis
Authors: Ignatova Velislava A. , Van Den Berghe Sven , Van Dyck Steven , Popok Vladimir N.
Published: September 2006

The oxide scales of AISI 304 formed in boric acid solutions at
300°C and pH = 4.5 have been studied using X-ray photoelectron
spectroscopy (XPS) depth profiling. The present focus is depth profile
quantification both in depth and chemical composition on a molecular
level. The roughness of the samples is studied by atomic force microscopy
before and after sputtering, and the erosion rate is determined by
measuring the crater depth with a surface profilometer and vertical
scanning interferometry. The resulting roughness (20–30 nm), being
an order of magnitude lower than the crater depth (0.2–0.5 μm),
allows layer-by-layer profiling, although the ion-induced effects result
in an uncertainty of the depth calibration of a factor of 2. The XPS
spectrum deconvolution and data evaluation applying target factor analysis
allows chemical speciation on a molecular level. The elemental
distribution as a function of the sputtering time is obtained, and the
formation of two layers is observed—one hydroxide (mainly
iron–nickel based) on top and a second one deeper, mainly consisting
of iron–chromium oxides.
Editorial
Authors: Lyman Charles E.
Published: September 2006

On September 1, 2006, the Microscopy and Microanalysis
electronic submission and review website went live. Our publisher,
Cambridge University Press, has teamed with ScholarOne to provide this
service. From now on all manuscript submissions to this journal must be
made electronically through the following website:

http://mc.manuscriptcentral.com/mam
Effects of nonlinearity on the structure of PSBL beamlets
Authors: Zelenyi L. M. , Dolgonosov M. S. , Peroomian V. , Ashour‐Abdalla M.
Published: September 2006

We investigate the nonlinear influence of the cross‐tail currents carried by beamlets (substructures of PSBL ion beams) on the topology of the magnetic field, and, correspondingly, on the dispersion properties of these substructures self‐consistently generated in this field. We found that some of the peculiarities of beamlet shapes found recently in CLUSTER data could be explained by taking into account the nonlinearity of the system. This model explains the steepening of local beamlets dispersion in comparison with the global dispersion of the enveloping VDIS structure. At the same time we found that velocity filter effects operating during beamlets propagation toward the Earth prevent the sign's reversal of this local dispersion.
Ground deformation associated with the precursory unrest and early phases of the January 2006 eruption of Augustine Volcano, Alaska
Authors: Cervelli P. F. , Fournier T. , Freymueller J. , Power J. A.
Published: September 2006

On January 11, 2006 Augustine Volcano erupted after nearly 20 years of quiescence. Global Positioning System (GPS) instrumentation at Augustine, consisting of six continuously recording, telemetered receivers, measured clear precursory deformation consistent with a source of inflation or pressurization beneath the volcano's summit at a depth of around sea level. Deformation began in early summer 2005, and was preceded by a subtle, but distinct, increase in seismicity, which began in May 2005. After remaining more or less constant, deformation rates accelerated on at least three stations beginning in late November 2005. After this date, GPS data suggest the upward propagation of a small dike into the edifice, which, based on the style of deformation and high levels of gas emission, appears to have ascended to shallow levels by mid‐December 2005, about four weeks before the eruption began.
A search for seismic radiation from late slip for the December 26, 2004 Sumatra‐Andaman (Mw = 9.15) earthquake
Authors: Velasco Aaron A. , Ammon Charles J. , Lay Thorne
Published: September 2006

The great 2004 Sumatra‐Andaman (Mw = 9.15) earthquake ruptured a 1300‐km‐long segment of the Sumatra‐Andaman Islands subduction zone in about nine minutes. The possibility of continued fault slip after the primary rupture has been raised by tsunami excitation models and by discrepancies between seismic slip models and geodetic observations. We examine the global seismic wavefield to identify any late seismic radiation that occurred during the first hour after the main rupture using stacking of deconvolutions and cross correlations of complete ground motion observations and point‐source responses (Green's functions). We find no evidence for delayed seismic radiation larger than Mw = 7.5. Any major slip within an hour after the main sliding with mechanism similar to the main shock involved deformation so slow that it radiated no detectable seismic waves in the body wave or surface wave passband for periods less than ∼500 s.
Topological characterization of crystallization of gold nanoclusters
Authors: Chui Yu Hang , Rees Robert J. , Snook Ian K. , O’Malley B. , Russo Salvy P.
Published: September 2006

In this study we use a new topological structure measure to analyze the local environment of 923 atom gold clusters quenched from the melt, at various quench rates, by molecular dynamics. The crystallization and geometrical rearrangements of the core atoms upon freezing can be clearly observed using our structure measure which is based on planar graphs. Our results support the hypothesis that crystallization is initiated from the surface and proceeds into the cluster core.
Torsion-vibration coupling in methanol: The adiabatic approximation and intramolecular vibrational redistribution scaling
Authors: Clasp Trocia N. , Perry David S.
Published: September 2006

The four-dimensional model Hamiltonian of Wang and Perry [J. Chem. Phys. 109, 10795 (1998)] is used to compare the approximate adiabatic separation of the torsion and CH stretches in methanol to an exact solution of the same Hamiltonian. The adiabatic approximation accounts for the pattern of the energy levels in the lowest torsional states, including the inverted tunneling splittings, but does not account for the pattern of systematic two- and four-fold near degeneracies at high torsional excitation. In the adiabatic basis, the nonadiabatic couplings mix the torsional and vibrational degrees of freedom and hence are a source for intramolecular vibrational redistribution (IVR). These IVR matrix elements are found to decrease by only a factor of 2 or 3 with each higher coupling order, in agreement with the results of Pearman and Gruebele [Z. Phys. Chem. Munich 214, 1439 (2000)]. This gentle scaling behavior, which contrasts with a steeper falloff with coupling order in more rigid molecules, points to a more important role for direct high-order couplings in torsional molecules. In this model, the scaling behavior derives from a single coupling term that is low order in the torsional angular momentum in combination with one-dimensional torsional functions that include contributions from many torsional angular momenta.
Controlling and characterizing the coagulation of liquid aerosol droplets
Authors: Buajarern Jariya , Mitchem Laura , Ward Andrew D. , Nahler N. Hendrik , McGloin David , Reid Jonathan P.
Published: September 2006

We demonstrate that optical tweezers can be used to control and characterize the coagulation and mixing state of aerosols. Liquid aerosol droplets of 2–14μm in diameter are optically trapped and characterized by spontaneous and stimulated Raman scatterings, which together provide a unique signature of droplet size and composition. From the conventional bright field image, the size of the trapped droplet can be estimated and compared with that determined from stimulated Raman scattering, and the motion of the particle within the trapping plane can be recorded. A maximum of four droplets can be manipulated in tandem by forming multiple optical traps through rapid beam steering. The coagulation of two droplets can be studied directly by controlling two droplets. The limiting conditions under which optical forces and capillary forces dominate the aerosol coagulation event are explored by varying the relative optical trap strengths and characterizing the coagulation of different droplet sizes. Finally, we demonstrate that the coagulation of different aerosol components can be compared and the mixing state of the final coagulated droplet can be investigated. In particular, we compare the outcome of the coagulation of an aqueous sodium chloride aerosol droplet with a second aqueous droplet, with an ethanol droplet or with a decane droplet.
The microwave spectrum of a two-top peptide mimetic: The N-acetyl alanine methyl ester molecule
Authors: Plusquellic David F. , Kleiner Isabelle , Demaison Jean , Suenram Richard D. , Lavrich Richard J. , Lovas Frank J. , Fraser Gerald T. , Ilyushin Vadim V.
Published: September 2006

The rotational spectrum of N-acetyl alanine methyl ester, a derivative of the biomimetic, N-acetyl alanine N′-methyl amide or alanine dipeptide, has been measured using a mini Fourier transform spectrometer between 9 and 25GHz as part of a project undertaken to determine the conformational structures of various peptide mimetics from the torsion-rotation parameters of low-barrier methyl tops. Torsion-rotation splittings from two of the three methyl tops capping the acetyl end of the –NH–C(O)– and the methoxy end of –C(O)–O– groups account for most of the observed lines. In addition to the AA state, two E states have been assigned and include an AE state having a torsional barrier of 396.45(7)cm−1 (methoxy rotor) and an EA state having a barrier of 64.96(4)cm−1 (acetyl rotor). The observed torsional barriers and rotational constants of alanine dipeptide and its methyl ester are compared with predictions from Møller-Plesset second-order perturbation theory (MP2) and density functional theory (DFT) in an effort to explore systematic errors at the two levels of theory. After accounting for zero-point energy differences, the torsional barriers at the MP2/cc-pVTZ level are in excellent agreement with experiment for the acetyl and methoxy groups while DFT predictions range from 8% to 80% too high or low. DFT is found to consistently overestimate the overall molecular size while MP2 methods give structures that are undersized. Structural discrepancies of similar magnitude are evident in previous DFT results of crystalline peptides.
First-principles electronic transport calculations in finite elongated systems: A divide and conquer approach
Authors: Hod Oded , Peralta Juan E. , Scuseria Gustavo E.
Published: September 2006

We present a first-principles method for the evaluation of the transmittance probability and the coherent conductance through elongated systems composed of a repeating molecular unit and terminated at both ends. Our method is based on a divide and conquer approach in which the Hamiltonian of the elongated system can be represented by a block tridiagonal matrix, and therefore can be readily inverted. This allows us to evaluate the transmittance and the conductance using first-principles electronic structure methods without explicitly performing calculations involving the entire system. A proof of concept model based on a trans-polyacetylene chain bridging two aluminum leads indicates that our divide and conquer approach is able to capture all the features appearing in the transmittance probability curves obtained by a full scale calculation.
Size distribution of nuclei in a closed system
Authors: Kožíšek Z. , Demo P. , Sveshnikov A. M.
Published: September 2006

Kinetic equations describing the formation of nuclei from a supersaturated vapor in a closed system are solved numerically to determine the size distribution of nuclei at various times. Depletion of vapor phase during phase transition process is taken into account. Evolution of the size distribution of nuclei is analyzed. Due to the decrease of the supersaturation of the vapor phase, a maximum appears in the size distribution of nuclei, which disappears at sufficiently long time. Supersaturation of the mother phase decreases to a value close to 1.
Magnetic interaction of submicron-sized ferromagnetic rings in one-dimensional array
Authors: Miyawaki T. , Toyoda K. , Kohda M. , Fujita A. , Nitta J.
Published: September 2006

Magnetization characteristics of submicron-sized ferromagnetic rings in a one-dimensional array with various inter-ring distances, lx, were investigated by the magneto-optical Kerr effect and micromagnetic simulation. The onion (vortex)-to-vortex (onion) transition fields were found to be proportional to 1∕lxn with n=1.36 (0.79), instead of being a simple dipole interaction model (n=3). It was demonstrated that the transition mechanism and the inter-ring dependence are governed by the energy gain originating from the deformation of the local vortex. As a result, exchange energy as well as magnetostatic energy play important roles in the magnetization reversal of ring array.
Magnetoelectric effect in Terfenol-D∕Pb(Zr,TiO)3∕μ-metal laminate composites
Authors: Dong Shuxiang , Zhai Jungyi , Li Jie-Fang , Viehland D.
Published: September 2006

The authors have found that the required dc magnetic bias of magnetoelectric (ME) laminates can be significantly altered, by incorporating additional high-permeability μ-metal layers. Investigations have focused on Tb1−xDyxFe2−y∕Pb(Zr1−xTix)O3∕μ-metal laminates. The authors’ results show that laminated μ-metal layers oriented perpendicular to an ac magnetic field concentrate flux in the composite, whereas those parallel to it attenuate flux. This results in (i) a significant decrease in the required dc magnetic bias Hdc, and (ii) an effective enhancement in the ME voltage coefficients at low Hdc, by a factor of up to 7.6.
Transmission characteristics of metallic equilateral triangular nanohole arrays
Authors: Kim Je Hong , Moyer Patrick J.
Published: September 2006

Transmission spectra through arrays of equilateral triangular nanoapertures show significant transmission increases for most conditions when normalized to the area ratio and compared to those of circular and square apertures. Also, the spectral features of the triangular holes are occasionally shifted when viewed with circular and square arrays of the same periodicity. The authors note that for apertures of the same area, the circumference of a triangular hole is about 75% larger than that of a square hole and about 100% larger than that of a circular hole, indicating that the perimeter region of the apertures may play a larger role in the transmission characteristics of nanoholes than has previously been noted. The authors suggest that the corresponding increase in metal surface area inside the apertures leads to a larger role played by the plasmon which is supported inside the apertures. The authors also suggest that the periodicity of the aperture arrays leads to diffraction effects which also affect the complex spectral characteristics of the transmitted light. Finally, for very small holes (less than 100nm in diameter), the significance of the triangular shape is diminished.
Growth and characterization of single crystal ZnO thin films using inductively coupled plasma metal organic chemical vapor deposition
Authors: Park J.-H. , Jang S.-J. , Kim S.-S. , Lee B.-T.
Published: September 2006

Zinc oxide thin films were grown on sapphire substrates by metal organic chemical vapor deposition technique. Single crystal films with flat and smooth surfaces were reproducibly obtained, with application of sample bias and O2 inductively coupled plasma (ICP). At the growth condition of 650°C, 400W ICP power, −94V bias voltage and O∕Zn ratio of 75, full width at half maximum values of room temperature photoluminescence and high-resolution x-ray diffraction were measured to be 126meV and 269arcsec, respectively. It was proposed that application of sample bias provided reactant ions with kinetic energy, which promoted formation of single crystalline films.
Formation of nanowaves in compressive fracture of a less-brittle bulk metallic glass
Authors: Shen J. , Liang W. Z. , Sun J. F.
Published: September 2006

Formation of periodical fracture surface marks in the dynamic fracture can only be observed, mainly in ideally brittle amorphous materials and under mode I loading conditions. Here the authors report on the observation of elastic-wave patterns on nanoscale that form in the compressive fracture process of a Ni-based alloy which is a less-brittle amorphous metal with an appreciable compressive ductility. The formation of nanowaves is evidenced via the creation of microbranching instability as well as the interaction of a crack front with the material inhomogeneities, i.e., microcracks.
Low temperature terahertz spectroscopy of n-InSb through a magnetic field driven metal-insulator transition
Authors: Gao X. P. A. , Sohn J. Y. , Crooker S. A.
Published: September 2006

The authors use fiber-coupled photoconductive emitters and detectors to perform terahertz spectroscopy of lightly doped n-InSb directly in the cryogenic (1.5K) bore of a high-field superconducting magnet. They measure transmission spectra from 0.1to1.1THz as the sample is driven through a metal-to-insulator transition (MIT) by applied magnetic field. In the low-field metallic state, the data directly reveal the plasma edge and magnetoplasmon modes. With increasing field, a surprisingly broad band (0.3–0.8THz) of low transmission appears at the onset of the MIT. This band subsequently collapses and evolves into the sharp 1s→2p− transition of electrons “frozen” onto isolated donors in the insulating state.
Terahertz beating of laser emission from an organic microcavity
Authors: Swoboda M. , Gehlhaar R. , Sudzius M. , Hoffmann M. , Fröb H. , Lyssenko V. G. , Leo K.
Published: September 2006

The authors present time-resolved studies of laser emission from an organic microcavity filled with a guest-host composite of tris(8-hydroxy quinoline) aluminium and 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran. A line splitting of 0.18THz between two perpendicularly polarized lines is observed, resulting from an optical anisotropy in the distributed Bragg reflectors. This particular behavior is attributed to oblique columnar structures shaped by off-axial preparatory conditions. By means of an upconversion setup an oscillation at 5.5ps period time and phase coupling of the modes are observed. A rate-equation-based approach is utilized for modeling the temporal behavior.
Composition dependence of band offsets for (LaAlO3)1−x(Al2O3)x gate dielectrics determined by photoelectron spectroscopy and x-ray absorption spectroscopy
Authors: Yasuhara R. , Komatsu M. , Takahashi H. , Toyoda S. , Okabayashi J. , Kumigashira H. , Oshima M. , Kukuruznyak D. , Chikyow T.
Published: September 2006

Electronic structures of (LaAlO3)1−x(Al2O3)x composite films (x=0, 0.2, 0.33, 0.5, and 1) for large scale integration (LSI) gate dielectrics deposited on p-type Si (100) substrates by a combinatorial pulsed laser deposition method have been analyzed using photoelectron spectroscopy and x-ray absorption spectroscopy. The systematic peak shifts due to chemical shifts were observed for core-level spectra. The conduction-band offset became smaller with increasing ratio of Al2O3, while the valence-band offset became larger. This precise determination of the band diagram revealed that LaAlO3 (x=0) had the optimum band offset for LSI gate dielectrics.
Structure and phase behavior of Widom-Rowlinson model calculated from a nonuniform Ornstein-Zernike equation
Authors: Malijevský Al. , Sokołowski S. , Zientarski T.
Published: September 2006

The second-order integral-equation formalism of [Attard J. Chem. Phys. 91, 3072 (1989); 95, 4471 (1991)], applied previously to one-component hard spheres and Lennard-Jones fluids, as well as to their mixtures, is used to binary Widom-Rowlinson mixtures. Comparison with Monte Carlo simulations of the pair correlation functions and of the demixing phase diagram shows that this method is also quite accurate in the case of highly nonadditive mixtures. Moreover, the results of the second-order theory are compared with previous theoretical predictions. Our interest is also in the calculation of the bridge functions, i.e., parts of the radial distribution functions either not included or simply approximated in the usual theories.
Autophagy-mediated reentry of
Francisella tularensis
into the endocytic compartment after cytoplasmic replication
Authors: Checroun Claire , Wehrly Tara D. , Fischer Elizabeth R. , Hayes Stanley F. , Celli Jean
Published: September 2006

Intracellular bacterial pathogens evade the bactericidal functions of mammalian cells by physical escape from their phagosome and replication into the cytoplasm or through the modulation of phagosome maturation and biogenesis of a membrane-bound replicative organelle. Here, we detail in murine primary macrophages the intracellular life cycle of
Francisella tularensis
, a highly infectious bacterium that survives and replicates within mammalian cells. After transient interactions with the endocytic pathway, bacteria escaped from their phagosome by 1 h after infection and underwent replication in the cytoplasm from 4 to 20 h after infection. Unexpectedly, the majority of bacteria were subsequently found to be enclosed within large, juxtanuclear, LAMP-1-positive vacuoles called
Francisella
-containing vacuoles (FCVs). FCV formation required intracytoplasmic replication of bacteria. Using electron and fluorescence microscopy, we observed that the FCVs contained morphologically intact bacteria, despite fusing with lysosomes. FCVs are multimembranous structures that accumulate monodansylcadaverine and display the autophagy-specific protein LC3 on their membrane. Formation of FCVs was significantly inhibited by 3-methyladenine, confirming a role for the autophagic pathway in the biogenesis of these organelles. Taken together, our results demonstrate that, via autophagy,
F. tularensis
reenters the endocytic pathway after cytoplasmic replication, a process thus far undescribed for intracellular pathogens.
Crystal structure of 12-oxophytodienoate reductase 3 from tomato: Self-inhibition by dimerization
Authors: Breithaupt Constanze , Kurzbauer Robert , Lilie Hauke , Schaller Andreas , Strassner Jochen , Huber Robert , Macheroux Peter , Clausen Tim
Published: September 2006

12-Oxophytodienoate reductase (OPR) 3, a homologue of old yellow enzyme (OYE), catalyzes the reduction of 9
S
,13
S
-12-oxophytodienoate to the corresponding cyclopentanone, which is subsequently converted to the plant hormone jasmonic acid (JA). JA and JA derivatives, as well as 12-oxophytodienoate and related cyclopentenones, are known to regulate gene expression in plant development and defense. Together with other oxygenated fatty acid derivatives, they form the oxylipin signature in plants, which resembles the pool of prostaglandins in animals. Here, we report the crystal structure of OPR3 from tomato and of two OPR3 mutants. Although the catalytic residues of OPR3 and related OYEs are highly conserved, several characteristic differences can be discerned in the substrate-binding regions, explaining the remarkable substrate stereoselectivity of OPR isozymes. Interestingly, OPR3 crystallized as an extraordinary self-inhibited dimer. Mutagenesis studies and biochemical analysis confirmed a weak dimerization of OPR3
in vitro
, which correlated with a loss of enzymatic activity. Based on structural data of OPR3, a putative mechanism for a strong and reversible dimerization of OPR3
in vivo
that involves phosphorylation of OPR3 is suggested. This mechanism could contribute to the shaping of the oxylipin signature, which is critical for fine-tuning gene expression in plants.
K
+
channel selectivity depends on kinetic as well as thermodynamic factors
Authors: Grabe Michael , Bichet Delphine , Qian Xiang , Jan Yuh Nung , Jan Lily Yeh
Published: September 2006

Potassium channels are necessary for a number of essential biological tasks such as the generation of action potentials and setting the resting membrane potential in cells, both of which require that these channels selectively permit the passage of potassium ions while suppressing the flow of other ions. Generally, this selectivity is attributed to a narrow stretch of the channel known as the selectivity filter. Over this stretch ions are dehydrated, and the backbone oxygen atoms of the protein mimic the ion's loss of coordination by water. However, channels are long pores with spatially distinct ion-binding sites that all must be traversed during ion permeation. We have shown that selectivity of mutant Kir3.2 (GIRK2) channels can be substantially amplified by introducing acidic residues into the cavity, a binding site below the selectivity filter. Here, we carry out electrostatic calculations on homology models to quantify the degree of stabilization that these mutations have on ions in the cavity. We then construct a multiion model of ion permeation to calculate the channel's permeability to potassium relative to sodium. This kinetic model uses rates derived from the electrostatic calculations and demonstrates that nonselective electrostatic stabilization of cations in the cavity can amplify channel selectivity independently of the selectivity filter. This nonintuitive result highlights the dependence of channel properties on the entire channel architecture and suggests that selectivity may not be fully understood by focusing solely on thermodynamic considerations of ion dehydration and the energetics of the selectivity filter.
Functional CD8+but not CD4+T cell responses develop independent of thymic epithelial MHC
Authors: Martinic Marianne M. , van den Broek Maries F. , Rülicke Thomas , Huber Christoph , Odermatt Bernhard , Reith Walter , Horvath Edit , Zellweger Raphael , Fink Katja , Recher Mike , Eschli Bruno , Hengartner Hans , Zinkernagel Rolf M.
Published: September 2006

The role of nonthymic epithelial (non-TE) MHC in T cell repertoire selection remains controversial. To analyze the relative roles of thymic epithelial (TE) and non-TE MHC in T cell repertoire selection, we have generated tetraparental aggregation chimeras (B6-nude↔BALB/c and B6↔BALB/c-nude) harboring T and B cells from both parents, whereas TE cells originated exclusively from the non-nude donor. These chimeras mounted protective virus-specific TE and non-TE MHC-restricted T cell responses. To further evaluate whether non-TE MHC alone was sufficient to generate a functional T cell repertoire, we generated tetraparental aggregation chimeras lacking MHC class II (B6-nude↔MHCII−/−) or both MHC molecules (B6-nude↔MHCI−/−II−/−) on TE cells, but not on cells of B6-nude origin. Chimeras with MHC-deficient TE cells mounted functional virus-specific CD8+but not CD4+T cell responses. Thus, maturation of functional CD4+T cell responses required MHC class II on thymic epithelium, whereas CD8+T cells matured in the absence of TE MHC.
p120 catenin is essential for mesenchymal cadherin–mediated regulation of cell motility and invasiveness
Authors: Yanagisawa Masahiro , Anastasiadis Panos Z.
Published: September 2006

During epithelial tumor progression, the loss of E-cadherin expression and inappropriate expression of mesenchymal cadherins coincide with increased invasiveness. Reexpression experiments have established E-cadherin as an invasion suppressor. However, the mechanism by which E-cadherin suppresses invasiveness and the role of mesenchymal cadherins are poorly understood. We show that both p120 catenin and mesenchymal cadherins are required for the invasiveness of E-cadherin–deficient cells. p120 binding promotes the up-regulation of mesenchymal cadherins and the activation of Rac1, which are essential for cell migration and invasiveness. p120 also promotes invasiveness by inhibiting RhoA activity, independently of cadherin association. Furthermore, association of endogenous p120 with E-cadherin is required for E-cadherin–mediated suppression of invasiveness and is accompanied by a reduction in mesenchymal cadherin levels. The data indicate that p120 acts as a rheostat, promoting a sessile cellular phenotype when associated with E-cadherin or a motile phenotype when associated with mesenchymal cadherins.
Nuclear import time and transport efficiency depend on importin β concentration
Authors: Yang Weidong , Musser Siegfried M.
Published: September 2006

Although many components and reaction steps necessary for bidirectional transport across the nuclear envelope (NE) have been characterized, the mechanism and control of cargo migration through nuclear pore complexes (NPCs) remain poorly understood. Single-molecule fluorescence microscopy was used to track the movement of cargos before, during, and after their interactions with NPCs. At low importin β concentrations, about half of the signal-dependent cargos that interacted with an NPC were translocated across the NE, indicating a nuclear import efficiency of ∼50%. At high importin β concentrations, the import efficiency increased to ∼80% and the transit speed increased approximately sevenfold. The transit speed and import efficiency of a signal-independent cargo was also increased by high importin β concentrations. These results demonstrate that maximum nucleocytoplasmic transport velocities can be modulated by at least ∼10-fold by the importin β concentration and therefore suggest a potential mechanism for regulating the speed of cargo traffic across the NE.
HDAC3 is crucial in shear- and VEGF-induced stem cell differentiation toward endothelial cells
Authors: Zeng Lingfang , Xiao Qingzhong , Margariti Andriana , Zhang Zhongyi , Zampetaki Anna , Patel Seema , Capogrossi Maurizio C. , Hu Yanhua , Xu Qingbo
Published: September 2006

Reendothelialization involves endothelial progenitor cell (EPC) homing, proliferation, and differentiation, which may be influenced by fluid shear stress and local flow pattern. This study aims to elucidate the role of laminar flow on embryonic stem (ES) cell differentiation and the underlying mechanism. We demonstrated that laminar flow enhanced ES cell–derived progenitor cell proliferation and differentiation into endothelial cells (ECs). Laminar flow stabilized and activated histone deacetylase 3 (HDAC3) through the Flk-1–PI3K–Akt pathway, which in turn deacetylated p53, leading to p21 activation. A similar signal pathway was detected in vascular endothelial growth factor–induced EC differentiation. HDAC3 and p21 were detected in blood vessels during embryogenesis. Local transfer of ES cell–derived EPC incorporated into injured femoral artery and reduced neointima formation in a mouse model. These data suggest that shear stress is a key regulator for stem cell differentiation into EC, especially in EPC differentiation, which can be used for vascular repair, and that the Flk-1–PI3K–Akt–HDAC3–p53–p21 pathway is crucial in such a process.
Direct optimization and multiple alignment of 28S D2–D3 rDNA sequences: problems with indels on the way to a molecular phylogeny of the cryptine ichneumon waSPS (Insecta: Hymenoptera)
Authors: Laurenne Nina M. , Broad Gavin R. , Quicke Donald L. J.
Published: September 2006

A molecular phylogeny of the Cryptinae based on the D2–D3 region of the 28S rDNA gene, including 176 cryptines representing 139 genera and an additional 77 outgroup genera, is presented. Direct optimization and multiple alignment each with a range of gap/substitution parameters were employed. The informal higher grouping of the ichneumonids were supported, but the relationship of the Ichneumoninae and Cryptinae was not resolved. Cryptinae tribes were supported but many genera formed constant groups that did not follow earlier subtribal divisions. We investigated artifactual placements of, e.g., Agriotypinae and Brachycyrtinae, and showed that they do not possess molecular synapomophies with the Ichenumoninae where direct optimization places them. The sequences of anomalous placed taxa were markedly longer (or in some cases shorter) than those of most other taxa, and this is explained by homoplastic indels at “hot spots” in the absence of large numbers of informative substitutions. We show that multiple alignment generally resulted in taxa with large insertions or deletions being placed in more plausible positions. The relationship of the genusAlomyais also explored.

© The Willi Hennig Society 2006.
Daclizumab, an efficient treatment for steroid‐refractory acute graft‐versus‐host disease
Authors: Bordigoni Pierre , Dimicoli Sophie , Clement Laurence , Baumann Cédric , Salmon Alexandra , Witz Francis , Feugier Pierre
Published: September 2006

In a phase II study, daclizumab was given as single second‐line agent to 62 patients with steroid‐refractory acute graft‐versus‐host disease (aGVHD). Complete resolution of aGVHD was achieved in 68·8% of patients. This response rate was significantly associated with a lower number of involved organs and smaller extent of skin involvement. The 4‐year event‐free survival (EFS) was 54·6%. Grade ≥III aGVHD, ≥2 involved organs at baseline and patient age >18 years were independently associated with lower EFS. Daclizumab could be a suitable alternative treatment for aGVHD, particularly when limited to the skin or gastrointestinal tract.