bluuebunny/crossref_metadata_2025 huggingface dataset:
Distinct efficacy of pre‐differentiated versus intact fetal mesencephalon‐derived human neural progenitor cells in alleviating rat model of Parkinson's disease
Authors: Wang Xuan , Lu Yanyan , Zhang Huanqing , Wang Kun , He Qihua , Wang Yue , Liu Xianyu , Li Linsong , Wang Xiaomin
Published: July 2004

Neural progenitor cells have shown the effectiveness in the treatment of Parkinson's disease, but the therapeutic efficacy remains variable. One of important factors that determine the efficacy is the necessity of pre‐differentiation of progenitor cells into dopaminergic neurons before transplantation. This study therefore investigated the therapeutic efficacy of mesencephalon‐derived human neural progenitor cells with or without the pre‐differentiation in alleviating a rat model of Parkinson's disease. We found that a combination of 50 ng/ml fibroblast growth factor 8, 10 ng/ml glial cell line‐derived neurotrophic factor and 10 μM forskolin facilitated the differentiation of human fetal mesencephalic progenitor cells into dopaminergic neurons in vitro. More importantly, after transplanted into the striatum of parkinsonian rats, only pre‐differentiated grafts resulted in an elevated production of dopamine in the transplanted site and the amelioration of behavioral impairments of the parkinsonian rats. Unlike pre‐differentiated progenitors, grafted intact progenitors rarely differentiated into dopaminergic neurons in vivo and emigrated actively away from the transplanted site.

These data demonstrates the importance of pre‐differentiation of human progenitor cells before transplantation in enhancing therapeutic potency for Parkinson's disease.
Chronic Finger Joint Instability Reconstructed With Bone–Ligament–Bone Graft from the Iliac Crest
Authors: WU W. C. , WONG T. C. , YIP T. H.
Published: July 2004

Five patients with chronic instability of digital joints presented with instability and functional disability. Two patients had ulnar collateral ligament damage of the thumb metacarpophalangeal joint and another had chronic multidirectional instability due to radial collateral ligament, dorsal capsule and palmar plate laxity of the metacarpophalangeal joint of the thumb. The fourth patient had a lax radial collateral ligament and palmar plate of the proximal interphalangeal joint of the little finger and the fifth had chronic laxity of the ulnar collateral ligament of the interphalangeal joint of the thumb. All were reconstructed with bone–ligament–bone graft harvested from the iliac crest. The graft was fixed with screws and joint stability was achieved intra-operatively in all patients. All patients achieved a stable joint with improved functional performance at final followup.
Evidence for differential control of tibial position in perturbed unilateral stance after acute ACL rupture
Authors: Chmielewski T. L. , Ramsey D. K. , Snyder‐Mackler L.
Published: July 2004

Functional outcomes in anterior cruciate ligament‐deficient “potential copers” and “non‐copers” may be related to their knee stabilization strategies. Therefore, the purpose of this study was to differentiate dynamic knee stabilization strategies of potential copers and non‐copers through analysis of sagittal plane knee angle and tibia position during disturbed and undisturbed unilateral standing. Ten uninjured potential coper and non‐coper subjects stood in unilateral stance on a platform that translated anteriorly, posteriorly and laterally. Knee angle and tibia position with reference to the femur were calculated before and after platform movement. During perturbation trials, potential copers maintained kinematics that were similar to uninjured subjects across conditions. Conversely, non‐copers stood with greater knee flexion than uninjured subjects and a tibia position that was more posterior than the other groups. Both non‐copers and potential copers demonstrated small changes in tibia position following platform movement, but direction of movement was not similar. The similarities between the knee kinematics of potential copers and uninjured subjects suggest that potential copers compensated well from their injury by utilizing analogous dynamic knee stabilization strategies. In comparison to the other groups, by keeping the knee in greater flexion and the tibia in a more posterior position, non‐copers appear to constrain the tibia in response to a challenging task, which is consistent with a “stiffening strategy”. Based on the poor functional outcomes of non‐copers, a stiffening strategy does not lead to dynamic knee stability, and the strategy may increase compressive forces which could contribute to or exacerbate articular cartilage degeneration. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
THE RULE OF LAW AND A CHANGE IN THE CONSTITUTION
Authors: Woolf Lord
Published: July 2004

Very substantial constitutional changes have been introduced or announced by the present Government. The article discusses these critically from the point of view of the senior judiciary.
ELIMINATING OBSTACLES TO FREEDOM OF ESTABLISHMENT: THE COMPETITIVE EDGE OF UK COMPANY LAW
Authors: Lowry John
Published: July 2004

This article examines the implications of the E.C.J.'s decisions in Überseering and Inspire Art against the background of the principal competing theories relating to lex societatis. It considers the tension between freedom of establishment (EC Treaty, arts 43 and 48) and the protective objectives of national corporate law regimes aimed at defeating the so-called Delaware effect. It goes on to argue that significant issues remain unresolved. More particularly, it questions whether creditor protection mechanisms contained in national insolvency laws will, in future, be viewed as obstacles to freedom of establishment.
‘BUSHVELD MAGIC’ AND ‘MIRACLE DOCTORS’–AN EXPLORATION OF EUGÈNE MARAIS AND C. LOUIS LEIPOLDT'S EXPERIENCES IN THE WATERBERG, SOUTH AFRICA, c. 1906–1917
Authors: SWART SANDRA
Published: July 2004

This article contributes to the critique of a particular historiographical construction of the rural socio-intellectual world of the Afrikaner, which portrays that world as narrowly Calvinist and culturally circumscribed, with rigidly patrolled racial borders. This challenge is effected through an investigation into the world of the Bushveld Boer through the work of Eugène Marais (1871–1936) and Christiaan Frederick Louis Leipoldt (1880–1947). The article seeks to show that the practical workings of agrarian race relations allowed for a certain measure of cultural osmosis, facilitating Afrikaner interest in African and traditional healing practices. Afrikaner interest in the paranormal and psychic, with an emphasis on European trends, is also investigated, to demonstrate that the image of intellectual isolation has been exaggerated. This is a contribution to the ongoing project of historians interested in Afrikaner identity, who probe the image of a monolithic, Calvinist past and stress variety and often secular thinking.
THE NATURE OF POWER: CAPE ENVIRONMENTAL HISTORY, THE HISTORY OF IDEAS AND NEOLIBERAL HISTORIOGRAPHY The Rise of Conservation in South Africa: Settlers, Livestock and the Environment, 1770–1950. By WILLIAM BEINART. Oxford: Oxford University Press, 2003. Pp. xxiii+402. £65 (ISBN 0-19-926151-2). Social History and African Environments. Edited by WILLIAM BEINART and JOANN MCGREGOR. Oxford: James Currey; Athens: Ohio University Press; Cape Town: David Philip, 2003. Pp. xii+275. £45 (ISBN 0-85255-951-8); £18.95, paperback (ISBN 0-85255-950-X). Environment, Power and Injustice: A South African History. By NANCY J. JACOBS. Cambridge: Cambridge University Press, 2003. Pp. xxi+300. £45; $65 (ISBN 0-521-81191-0); £16.95; $24, paperback (ISBN 0-521-01070-5).
Authors: VAN SITTERT LANCE
Published: July 2004

For a region purportedly a backwater of South African environmental history at the close of the twentieth century,1 the Cape has moved rapidly toward centre stage at the start of the new millennium. It now boasts a wealth of literature in international journals and last year saw the publication of the first book-length environmental histories of the region, with the promise of still more to come, not least from a strong crop of recently or nearly completed doctoral dissertations in academies round the north Atlantic rim.2 The Cape owes this distinction to being the oldest region of British missionary and imperial endeavour in the subcontinent, guaranteeing extensive archives in the northern hemisphere and explaining both the bias in the current scholarship towards the pre-1910 period and lack of a comparable scholarship on any other part of southern Africa.3 This anomalous florescence can also be read for likely future trends in a national historiography otherwise unanimously deemed moribund if not actually in decline for the past decade.4 What it reveals are two contending trajectories: the first a shift away from political economy to the history of ideas and the other a fidelity to the late twentieth-century radical social history tradition and its core theme of the social relations of production.
György Ligeti and the Rhetoric of Autonomy
Authors: WILSON CHARLES
Published: July 2004

Composers’ self-representations – in articles, programme notes, and interviews – have exerted a significant influence on twentieth-century music scholarship, shaping not only the reception of particular outputs but also wider historiographical conceptions of the recent past. This article traces one particular mode of discourse through the published statements of György Ligeti – a ‘rhetoric of autonomy’, which tends to disavow allegiances to ‘schools’ or institutions and underplay stylistic or aesthetic commonalities with the work of other composers. This type of rhetoric, together with the image it promotes of an artistic culture created out of the polarized activities of individuals, colludes naturally with the now familiar pluralist paradigm of late-twentieth-century culture, a paradigm that much postmodern theory, despite its putative deconstruction of the ‘ideology of the unique self’ (Jameson), has left largely unchallenged. Except that, for an artist such as Ligeti, the rhetoric of autonomy may no longer accomplish its objective purpose. Within a cultural sphere increasingly subsumed by the commercial, the image of the radically autonomous creator, once powerfully symbolic of a refusal of the mass market, becomes inescapably caught up in its mechanisms as an explicitly promotional tool.
(Ac)cumulative Form in Pop-Rock Music
Authors: SPICER MARK
Published: July 2004

This article examines a variety of compositional procedures that give rise to what the author defines as ‘accumulative’ and ‘cumulative’ forms in pop-rock music, formal processes which are directly linked to the rapid advances in recording technology that occurred mainly from the late 1960s to the 1980s. The article includes detailed transcriptions and analyses of pop-rock music across a wide range of styles and genres, from progressive rock to post-punk to techno.
Stalin and the Art of Boredom
Authors: FROLOVA-WALKER MARINA
Published: July 2004

Socialist Realist ceremonial art has generally been viewed in the West as a form of high art, because of its air of monumentality and references to classics. Judged by high-art standards, such works are invariably failures, and Western commentators have accordingly treated Socialist Realism as something exotic or inexplicable. This approach is inadequate: firstly, because it does not examine Stalin-era art on its own terms, and secondly, because it refuses to acknowledge any similarities in Western culture.

Socialist Realism was a discipline placed upon artists to provide a suitably dignified backdrop to state ritual. In this sense, it was a species of religious art, in which blandness, anonymity and tedium were by no means vices. This article compares the relatively smooth passage of Myaskovsky into Socialist Realism with the troubled homecoming of Prokofiev, who only mastered the discipline just before the end of his life.
Postmodern Musicology in Combined Development: a Review of Judy Lochhead and Joseph Auner, eds, Postmodern Music / Postmodern Thought (New York and London: Routledge, 2002), ISBN 0815338198 (hb), 0815338201 (pb)
Authors: Krims Adam
Published: July 2004

In Trotsky’s classic theory of uneven development, ‘combined development’ designates how some regions may graft characteristics of new production relations onto older formations: examples might include the information economies of Guangzhou and Lagos, integrated to early capitalist, or even older, social orders. ‘Combined development’ provides a handy metaphor for Postmodern Music / Postmodern Thought, suggesting the grafting of post-Marxist ‘postmodern theory’ onto a musicological field that never substantively encountered Marxism, instead embracing ideologies that had already repudiated it.
On the Risk of Extinction for a Population Subject to a Random Markov Evolution with Jumps
Authors: Abundo Mario
Published: July 2004

We consider a one-dimensional population whose evolution is described by a jump-diffusion equation and we study the effects of changing the coefficients of the equation on the extinction time, that is the instant at which the population becomes arbitrarily small. It is shown that, under the same diffusion coefficient, if one reduces the drift and the size of jumps, the speed of extinction increases; moreover, the probability of reaching a higher population state than the present one before reaching a lower population size decreases. If the diffusion coefficient is state-independent, the speed of extinction increases with it. Furthermore, if no jumps are allowed (i.e. for a simple-diffusion equation), then under certain conditions on the coefficients of the equation both large and small values of the diffusion coefficient result in a higher extinction risk.
A Variational Ecological-Type Optimization of Some Thermal-Engine Models
Authors: Arias-Hernández L. A. , de Parga G. Ares , Angulo-Brown F.
Published: July 2004

In a recent work [23] we have analyzed a nonendoreversible thermal engine model under two maximization criteria: the maximum power regime and the so-called ecological criterion. In the present work, we extend the study of the same class of nonendoreversible models, but by using the so-named generalized ecological criterion [15]. This criterion is based on a family of ecological-type functions depending on a parameter associated to the particular heat transfer law used in the engine model. By means of this criterion we find a simplification of some of the results obtained in [23] by using both conventional and variational calculus. Besides, we propose a simple procedure to calculate the parameter involved in the generalized ecological function.
Entropy Based Approach to Data Loss Reparation Through the Indeterminate Fine-Grained Parallel Computation
Authors: Nemenchinskaya Ekaterina O. , Kondratenko Yuri V. , Sadovsky Michael G.
Published: July 2004

The new method of a gap recovery in symbol sequences is presented. A covering is combined from the suitable reasonably short strings of the parts of a sequence available for observation. Two criteria are introduced to choose the best covering. It must yield the maximum of entropy of a frequency dictionary developed over the sequence obtained due to the recovery, if an overlapping combined from the copies of strings from the available parts of the sequence exists. The second criterion identifies the best covering in case when one has to use any string to cover the gap; here the best covering must yield the minimum of specific entropy of the frequency dictionary developed over the available parts of the sequence against the one developed over the entire sequence obtained due to the recovery. Kirdin kinetic machine which is the ideal finegrained structureless computer has been used to resolve the problem of the reconstruction of a gap in symbol sequence.
Protein and solvent dynamics: How strongly are they coupled?
Authors: Caliskan G. , Mechtani D. , Roh J. H. , Kisliuk A. , Sokolov A. P. , Azzam S. , Cicerone M. T. , Lin-Gibson S. , Peral I.
Published: July 2004

Analysis of Raman and neutron scattering spectra of lysozyme demonstrates that the protein dynamics follow the dynamics of the solvents glycerol and trehalose over the entire temperature range measured 100–350 K. The protein’s fast conformational fluctuations and low-frequency vibrations and their temperature variations are very sensitive to behavior of the solvents. Our results give insight into previous counterintuitive observations that protein relaxation is stronger in solid trehalose than in liquid glycerol. They also provide insight into the effectiveness of glycerol as a biological cryopreservant.
Theoretical investigation of substituted anthraquinone dyes
Authors: Jacquemin Denis , Preat Julien , Charlot Magali , Wathelet Valérie , André Jean-Marie , Perpète Eric A.
Published: July 2004

We have investigated with computational chemistry techniques the visible spectra of substituted anthraquinones. A wide panel of theoretical methods has been used, with various basis sets and density functional theory (DFT) functionals, in order to assess a level of theory that would lead to converged excitation energies. It turns out that the hybrid Becke-Lee-Yang-Parr and Perdew-Burke-Erzenrhof functionals with the 6-31G (d,p) atomic basis set provide reliable λmax when the solvent effects are included in the model. Combining the results of both DFT schemes allows the prediction of λmax with a standard deviation limited to 13 nm.
Molecular electronics, negative differential resistance, and resonant tunneling in a poled molecular layer on Al∕LiF electrodes having a sharp density of states
Authors: Lu Z. H. , Khangura R. S. , Dharma-wardana M. W.C. , Zgierski Marek Z. , Ritchie Douglas
Published: July 2004

Density-functional calculations clarify the role of an ultrathin LiF layer on Al electrodes used in molecular electronics. The LiF layer creates a sharp density of states (DOS), as in a scanning-tunneling microscope (STM) tip. The sharp DOS, coupled with the DOS of the molecule leads to negative differential resistance. Electron transfer between oriented molecules occurs via resonant tunneling. The I–V characteristic for a thin-film of tris (8-hydroxyquinoline)-aluminum (AIQ) molecules, oriented using electric-field poling, is in excellent agreement with theory. This molecular is a robust, simple alternative to STM or mechanical break-junction structures.
Intermolecular interaction in an open-shell π-bound cationic complex: IR spectrum and coupled cluster calculations for C2H2+-Ar
Authors: Dopfer Otto , Olkhov Rouslan V. , Mladenović Mirjana , Botschwina Peter
Published: July 2004

The intermolecular potential energy surface (PES) of Ar interacting with the acetylene cation in its Πu2 ground electronic state is characterized by infrared photodissociation (IRPD) spectroscopy and quantum chemical calculations. In agreement with the theoretical predictions, the rovibrational analysis of the IRPD spectrum of C2H2+-Ar recorded in the vicinity of the antisymmetric CH stretching fundamental (ν3) is consistent with a vibrationally averaged T-shaped structure and a ground-state center-of-mass separation of Rc.m.=2.86±0.09 Å. The ν3 band experiences a blueshift of 16.7 cm−1 upon complexation, indicating that vibrational excitation slightly reduces the interaction strength. The two-dimensional intermolecular PES of C2H2+-Ar, obtained from coupled cluster calculations with a large basis set, features strong angular-radial coupling and supports in addition to a global π-bound minimum also two shallow side wells with linear H-bound geometries. Bound state rovibrational energy level calculations are carried out for rotational angular momentum J=0–10 (both parities) employing a discrete variable representation–distributed Gaussian basis method. Effective spectroscopic constants are determined for the vibrational ground state by fitting the calculated rotational energies to the standard Watson A-type Hamiltonian for a slightly asymmetric prolate top.
Intramolecular vibrational energy redistribution in bridged azulene-anthracene compounds: Ballistic energy transport through molecular chains
Authors: Schwarzer D. , Kutne P. , Schröder C. , Troe J.
Published: July 2004

Intramolecular vibrational energy flow in excited bridged azulene-anthracene compounds is investigated by time-resolved pump-probe laser spectroscopy. The bridges consist of molecular chains and are of the type (CH2)m with m up to 6 as well as (CH2OCH2)n (n=1,2) and CH2SCH2. After light absorption into the azulene S1 band and subsequent fast internal conversion, excited molecules are formed where the vibrational energy is localized at the azulene side. The vibrational energy transfer through the molecular bridge to the anthracene side and, finally, to the surrounding medium is followed by probing the red edge of the azulene S3 absorption band at 300 nm and/or the anthracene S1 absorption band at 400 nm. In order to separate the time scales for intramolecular and intermolecular energy transfer, most of the experiments were performed in supercritical xenon where vibrational energy transfer to the bath is comparably slow. The intramolecular equilibration proceeds in two steps. About 15%–20% of the excitation energy leaves the azulene side within a short period of 300 fs. This component accompanies the intramolecular vibrational energy redistribution (IVR) within the azulene chromophore and it is caused by dephasing of normal modes contributing to the initial local excitation of the azulene side and extending over large parts of the molecule. Later, IVR in the whole molecule takes place transferring vibrational energy from the azulene through the bridge to the anthracene side and thereby leading to microcanonical equilibrium. The corresponding time constants τIVR for short bridges increase with the chain length. For longer bridges consisting of more than three elements, however, τIVR is constant at around 4–5 ps. Comparison with molecular dynamics simulations suggests that the coupling of these chains to the two chromophores limits the rate of intramolecular vibrational energy transfer. Inside the bridges the energy transport is essentially ballistic and, therefore, τIVR is independent on the length.
Thermal conductivity, thermal effusivity, and specific heat capacity near the lower critical point of the binary liquid mixture n-butoxyethanol–water
Authors: Pittois S. , Van Roie B. , Glorieux C. , Thoen J.
Published: July 2004

Experimental investigations on binary liquid mixtures near the critical mixing point are presently leading to a controversy about the anomaly in the thermal conductivity. A photopyroelectric technique is used to determine the thermal conductivity and the effusivity of the binary liquid mixture n-butoxyethanol–water at its critical concentration near the critical mixing point. It is proven that, contrary to previous reports, there is no critical enhancement in the thermal conductivity. The specific heat capacity is calculated from these results and compared with the results from measurements performed by adiabatic scanning calorimetry.
Dissociation of the ground state vinoxy radical and its photolytic precursor chloroacetaldehyde: Electronic nonadiabaticity and the suppression of the H+ketene channel
Authors: Miller Johanna L. , McCunn Laura R. , Krisch Maria J. , Butler Laurie J. , Shu Jinian
Published: July 2004

This work is a study of the competition between the two unimolecular reaction channels available to the vinoxy radical (CH2CHO), C–H fission to form H+ketene, and isomerization to the acetyl radical (CH3CO) followed by C–C fission to form CH3+CO. Chloroacetaldehyde (CH2ClCHO) was used as a photolytic precursor to the vinoxy radical in its ground state; photodissociation of chloroacetaldehyde at 193 nm produces vinoxy radicals with internal energies spanning the G3//B3LYP calculated barriers to the two available unimolecular reaction channels. The onset of the CH3+CO channel, via isomerization to the acetyl radical, was found to occur at an internal energy of 41±2 kcal/mol, agreeing well with our calculated isomerization barrier of 40.8 kcal/mol. Branching to the H+ketene channel was too small to be detected; we conclude that the branching to the H+ketene channel must be at least a factor of 200 lower than what is predicted by a RRKM analysis based on our electronic structure calculations. This dramatic result may be explained in part by the presence of a conical intersection at planar geometries along the reaction coordinate leading to H+ketene, which results in electronically nonadiabatic recrossing of the transition state.
Franck-Condon simulation of the single-vibronic-level emission spectra of HPCl/DPCl and the chemiluminescence spectrum of HPCl, including anharmonicity
Authors: Chau Foo-tim , Mok Daniel K. W. , Lee Edmond P. F. , Dyke John M.
Published: July 2004

Restricted-spin coupled-cluster single-double plus perturbative triple excitation [RCCSD(T)] potential energy functions (PEFs) were calculated for the X̃ 2A″ and Ã 2A′ states of HPCl employing the augmented correlation-consistent polarized-valence-quadruple-ζ (aug-cc-pVQZ) basis set. Further geometry optimization calculations were carried out on both electronic states of HPCl at the RCCSD(T) level with all electron and quasirelativistic effective core potential basis sets of better than the aug-cc-pVQZ quality, and also including some core electrons, in order to obtain more reliable geometrical parameters and relative electronic energy of the two states. Anharmonic vibrational wave functions of the two states of HPCl and DPCl, and Franck-Condon (FC) factors of the Ã 2A′-X̃ 2A″ transition were computed employing the RCCSD(T)/aug-cc-pVQZ PEFs. Calculated FC factors with allowance for Duschinsky rotation and anharmonicity were used to simulate the single-vibronic-level (SVL) emission spectra of HPCl and DPCl reported by Brandon et al. [J. Chem. Phys. 119, 2037 (2003)] and the chemiluminescence spectrum reported by Bramwell et al. [Chem. Phys. Lett. 331, 483 (2000)]. Comparison between simulated and observed SVL emission spectra gives the experimentally derived equilibrium geometry of the Ã 2A′ state of HPCl of re(PCl)=2.0035±0.0015 Å, θe=116.08±0.60°, and re(HP)=1.4063±0.0015 Å via the iterative Franck-Condon analysis procedure. Comparison between simulated and observed chemiluminescence spectra confirms that the vibrational population distribution of the Ã 2A′ state of HPCl is non-Boltzmann, as proposed by Baraille et al. [Chem. Phys. 289, 263 (2003)].
Anharmonic quantum contribution to vibrational dephasing
Authors: Barik Debashis , Ray Deb Shankar
Published: July 2004

Based on a quantum Langevin equation and its corresponding Hamiltonian within a c-number formalism we calculate the vibrational dephasing rate of a cubic oscillator. It is shown that leading order quantum correction due to anharmonicity of the potential makes a significant contribution to the rate and the frequency shift. We compare our theoretical estimates with those obtained from experiments for small diatomics N2, O2, and CO.
Formation of HXeO in a xenon matrix: Indirect evidence of production, trapping, and mobility of XeO (1 1Σ+) in solid Xe
Authors: Kiviniemi Tiina , Pettersson Mika , Khriachtchev Leonid , Räsänen Markku , Runeberg Nino
Published: July 2004

IR spectroscopy, laser induced fluorescence (LIF), and thermoluminescence (TL) measurements have been combined to monitor trapping, thermal mobility, and reactions of oxygen atoms in solid xenon. HXeO and O3 have been used as IR active species that probe the reactions of oxygen atoms. N2O and H2O have been used as precursors for oxygen atoms by photolysis at 193 nm. Upon annealing of matrices after photolysis, ozone forms at two different temperatures: at 18–24 K from close O⋯O2 pairs and at ∼27 K due to global mobility of oxygen atoms. HXeO forms at ∼30 K reliably at higher temperature than ozone. Both LIF and TL show activation of oxygen atoms around 30 K. Irradiation at 240 nm after the photolysis at 193 nm depletes the oxygen atom emission at 750 nm and reduces the amount of HXeO generated in subsequent annealing. Part of the 750 nm emission can be regenerated by 266 nm and this process increases the yield of HXeO in annealing as well. Thus, we connect oxygen atoms emitting at 750 nm with annealing-induced formation of HXeO radicals. Ab initio calculations at the CCSD(T)/cc-pV5Z level show that XeO (1 1Σ+) is much more deeply bound [De=1.62 eV for XeO→Xe+O(1D)] than previous calculations have predicted. Taking into account the interactions with the medium in an approximate way, it is estimated that XeO (1 1Σ+) has a similar energy in solid xenon as compared with interstitially trapped O (3P) suggesting that both possibly coexist in a low temperature solid. Taking into account the computational results and the behavior of HXeO and O3 in annealing and irradiations, it is suggested that HXeO may be formed from singlet oxygen atoms which are trapped in a solid as XeO (1 1Σ+).
Sign-consistent dynamical couplings between ab initio three-center wave functions
Authors: Errea L. F. , Fernández L. , Macı́as A. , Méndez L. , Rabadán I. , Riera A.
Published: July 2004

We present a method to ensure the sign consistency of dynamical couplings between ab initio three-center wave functions. The method also allows to systematically “diabatize” avoided crossings between two potential energy surfaces, including conical intersections. Illustrations are presented for H3+, LiH2+, and NH25+ quasimolecules.
Calculation of the photodetachment cross sections of the HCN− and HNC− dipole-bound anions as described by a one-electron Drude model
Authors: Sindelka M. , Spirko V. , Jungwirth P. , Wang F. , Mahalakshmi S. , Jordan K. D.
Published: July 2004

The Drude model for treating the interaction of excess electrons with polar molecules is extended to calculate continuum functions and to evaluate photodetachment cross sections. The approach is applied to calculate the cross sections for photodetachment of dipole-bound electrons from HCN− and HNC−. In addition, an adiabatic model separating the angular and radial degrees of freedom of the excess electron is introduced and shown to account in a qualitative manner for the cross sections.
Photonic crystal assembled from nonmagnetic wire split rings
Authors: Liniauskas A. , Brazis R.
Published: July 2004

Monoclinic-symmetry photonic crystals assembled from identically oriented copper wire split rings are found to manifest photon nontransmission bands related to the electric and magnetic dipole excitations of the interacting oscillators. The width and form of the bands are shown to depend on photon polarization and propagation direction with respect to the crystal axes. The single split-ring resonance lines are shown for comparison. The ring diameter and the crystal lattice constant are significantly less than the electromagnetic wavelength. Experimental data are compared to the mean-field model including the series of oscillator functions for electric and magnetic polarization.
Quantum treatment of the Ar-HI photodissociation dynamics
Authors: López-López Sergio , Prosmiti Rita , Garcı́a-Vela Alberto
Published: July 2004

A wave packet simulation of the ultraviolet photolysis dynamics of Ar-HI(v=0) is reported. Cluster photodissociation is started from two different initial states, namely, the ground van der Waals (vdW) and the first excited vdW bending state, associated with the Ar-I-H and Ar-H-I isomeric forms of the system, respectively. Formation of Ar-I radical products is investigated over the energy range of the cluster absorption spectrum. It is found that the yield of bound Ar-I radical complexes is typically 90%–100% and 70%–80% for the initial states associated with the Ar-I-H and Ar-H-I isomers, respectively. This result is in agreement with the experimentally observed time-of-flight spectrum of the hydrogen fragment produced after Ar-HI photodissociation. The high Ar-I yield is explained mainly by the small amount of energy available for the radical that is converted into internal energy in the photofragmentation process, which enhances the Ar-I survival probability. Quantum interference effects manifest themselves in structures in the angular distribution of the hydrogen fragment, and in pronounced rainbow patterns in the rotational distributions of the Ar-I radical.
The density distributions of the counterions and the coions confined in two similarly charged plates
Authors: Li Cuilian , Ma H. R.
Published: July 2004

By using the field-theoretic method, we established a unified systematic formulation of a model of counterions and coions confined in two similarly charged plates, and calculated the density distributions of counterions and coions with various coupling parameters by the two methods: Poisson-Boltzmann (PB) approach and the strong coupling (SC) theory, respectively. We also performed Monte Carlo simulations, and obtained the density distributions of counterions and coions with several different coupling parameters. Comparing our theoretical results with those from Monte Carlo simulation, we find that the PB approach is valid when the coupling parameter Ⅺ is smaller than 1, but, as Ⅺ⩾1, the results by the PB approach deviate from the corresponding Monte Carlo simulation data, and the deviation gets larger with the coupling parameter increasing. This shows that the PB approach is completely invalid when the coupling parameter is equal to 1 or larger than 1. For the latter case, the development trend of the distribution curve calculated by SC theory agrees with that from Monte Carlo simulation as the coupling parameter increases. This demonstrates that the SC theory can give a qualitative available explanation on the density distribution of the counterions in the system in which the coupling parameters are strictly confined.
Exchange-assisted nonlinear bit shift reduction at high linear densities in synthetic ferrimagnetic media
Authors: Ajan Antony , Abarra E. N. , Inomata A. , Shinohara M. , Yamagishi W.
Published: July 2004

Synthetic ferrimagnetic media comprised of two magnetic layers tend to exhibit larger nonlinear transition shift (NLTS) compared to single magnetic layer conventional media. NLTS is reduced by increasing the antiferromagnetic exchange field (Hex) and especially by employing a lower layer with high magnetization and thickness product (Mst). Due to the lower switching field of the stabilization layer, the position of the transition during writing is farther downstream than that of the upper layer. We suggest that, at high densities, the pinning of the lower layer transition below the nearest neighboring upper layer transition leads to a reduction of demagnetizing fields and therefore NLTS.
White beam x-ray waveguide optics
Authors: Jarre A. , Salditt T. , Panzner T. , Pietsch U. , Pfeiffer F.
Published: July 2004

We report a white beam x-ray waveguide (WG) experiment. A resonant beam coupler x-ray waveguide (RBC) is used simultaneously as a broad bandpass (or multibandpass) monochromator and as a beam compressor. We show that, depending on the geometrical properties of the WG, the exiting beam consists of a defined number of wavelengths which can be shifted by changing the angle of incidence of the white x-ray synchrotron beam. The characteristic far-field pattern is recorded as a function of exit angle and energy. This x-ray optical setup may be used to enhance the intensity of coherent x-ray WG beams since the full energetic acceptance of the WG mode is transmitted.
Correlation of the generation-recombination noise with reliability issues of polycrystalline silicon thin-film transistors
Authors: Hastas N. A. , Dimitriadis C. A. , Kamarinos G.
Published: July 2004

Low-frequency noise measurements have been carried out in polycrystalline silicon thin-film transistors (polysilicon TFTs) with different interface roughnesses. Independently of the interface roughness, the drain current noise can be ascribed to carrier number fluctuations. In devices with a large interface roughness, a noise overshoot is observed at drain currents around 3μA, attributed to generation-recombination (g-r) centers. The traps responsible for the g-r noise are located within the gate oxide near the interface, created by the carriers injected into the gate oxide by the field enhanced at the rough polysilicon∕SiO2 interface. The g-r noise corresponds to a single trap level of density 3.8×1017cm−3 and time constant 20ms. Devices exhibiting g-r noise degrade more rapidly during electrical stress.
Interface states and depletion-induced threshold voltage instabilityin organic metal-insulator-semiconductor structures
Authors: Torres I. , Taylor D. M. , Itoh E.
Published: July 2004

We present results obtained from a study of the admittance of metal-insulator-semiconductor capacitors formed from regioregular poly(3-hexylthiophene). Data obtained over a range of applied bias and frequency can be explained by the presence of a distribution of trapping states at the insulator∕semiconductor interface as observed in metal-oxide-silicon capacitors. We also observe a depletion-bias instability in the threshold voltage, VT, that is consistent with negative charge trapping at the insulator∕polymer interface. The shift can be relaxed by illumination with bandgap light, λ=550nm, suggesting that the instability arises from an electronic process.
Finite coplanar waveguide width effects in pulsed inductivemicrowave magnetometry
Authors: Schneider M. L. , Kos A. B. , Silva T. J.
Published: July 2004

The effect of finite coplanar waveguide (CPW) width on the measurement of the resonance frequency in thin ferromagnetic films has been characterized for pulsed inductive microwave magnetometry. A shift in resonant frequency is a linear function of the ratio of sample thickness to CPW width. The proportionality constant is experimentally determined to be 0.74±0.1 times the saturation magnetization of the film. The frequency shift may be modeled as arising from an effective magnetic-anisotropy field.
Internal stress storage in shape memory polymer nanocomposites
Authors: Gall Ken , Dunn Martin L. , Liu Yiping , Stefanic Goran , Balzar Davor
Published: July 2004

We examine the storage and release of internal stresses in shape memory polymers reinforced with a dispersion of nanometer-scale SiC particles. A quantitative Rietveld analysis of diffraction peaks was used to measure changes in the lattice parameter of the SiC particles after permanent deformation at 25°C, and subsequent shape recovery induced by heating to 120°C. Under 50% compression of the composite material, the nanoparticles store a finite compressive stress, which is almost completely released during heated strain recovery. The values of the stored internal stresses in the particles are compared to values based on micromechanic calculations.
An algorithm for eigenvalues and eigenvectors of quaternion matrices in quaternionic quantum mechanics
Authors: Jiang Tongsong
Published: July 2004

By means of complex representation and companion vector, this paper studies the problems of eigenvalues and eigenvectors of quaternion matrices, and gives a technique of computing the eigenvalues and eigenvectors of the quaternion matrices in quaternionic quantum mechanics.
Enhancement of low-field magnetoresistance in polycrystalline Sr2FeMoO6 with Al doping
Authors: Sui Y. , Wang X. J. , Qian Z. N. , Cheng J. G. , Liu Z. G. , Miao J. P. , Li Y. , Su W. H. , Ong C. K.
Published: July 2004

Polycrystalline Sr2Fe1−xAlxMoO6 compounds with x=0, 0.05, 0.10, 0.15, and 0.30 were fabricated and their low-field magnetoresistance (LFMR) performance studied. The LFMR was greatly enhanced as x increased from nil to 0.15, and its origin was found to be intragranular spin-dependent scattering. The replacement of Fe by Al weakened the antiferromagnetic exchange in the antiphase boundary arising from the antisite defect and acted as a barrier for electron transport along the Mo–O–Fe–O–Mo–O–Fe chain in the ferromagnetic segregation and weakened the ferromagnetic exchange. When the external magnetic field was applied, the spin in the antiphase boundary appeared to align more easily to the external field after Al doping and the transport of the electron was easier due to the weakening of the double exchange barrier.
Effective-mean-field approach for macroscopic elastic constantsof composites
Authors: Tane Masakazu , Ichitsubo Tetsu
Published: July 2004

We propose an evaluation method for macroscopic elastic constants of composites, which is called the effective-mean-field method. The method is based on Mori–Tanaka’s mean-field (MTMF), and the effective-medium approximation methods, in which complex elastic fields disturbed by many inclusions are replaced by the average fields of a virtually homogenized composite, and the MTMF formulae are utilized in the entire fraction range of inclusion. It is demonstrated for porous samples that the proposed method can reproduce power-law behavior with regard to porosity.
Physical origin of trench formation in Ge∕Si(100) islands
Authors: Sonnet Ph. , Kelires P. C.
Published: July 2004

Monte Carlo simulations of stress buildup and relief shed light onto the physical origin of trench formation in Ge∕Si(100) islands. By monitoring the stress evolution as the island grows layer by layer, we find that a trench is most likely being formed halfway during growth. The primary driving force for this phenomenon is the reduction of the concentrated stress below the edges of the island, but not the need to provide Si into it, as is widely believed. However, once the trench is formed, subsequent intermixing through it is enhanced, and nearly compensates for the stress in the island.
Preparation of thermally stable TiO2-terminated SrTiO3(100) substrate surfaces
Authors: Ohnishi T. , Shibuya K. , Lippmaa M. , Kobayashi D. , Kumigashira H. , Oshima M. , Koinuma H.
Published: July 2004

We have examined the thermal stability of TiO2-terminated SrTiO3(100) surfaces obtained by buffered HF etching and widely used as substrates for oxide film growth. In situ coaxial impact-collision ion scattering spectroscopy was used to measure the composition of the terminating atomic layer at temperatures up to 1000°C, simulating a broad range of thin-film growth conditions. The TiO2 termination of a nonannealed but HF-etched surface was found to start collapsing at temperatures as low as 300°C regardless of atmosphere, showing thermal instability of the chemically cleaved surface. Here, we introduce an alternative way to prepare a stabilized SrTiO3 surface, which maintains a perfect TiO2 termination up to 700°C, ideal for the growth of atomically sharp oxide heterointerfaces.
Three-dimensional patterned media for ultrahigh-density optical memory
Authors: Nakano Masaharu , Kooriya Takaaki , Kuragaito Takashi , Egami Chikara , Kawata Yoshimasa , Tsuchimori Masaaki , Watanabe Osamu
Published: July 2004

We report a recording medium in which a three-dimensional nanoscale structure can be photofabricated for multilayered optical memory using a two-photon process. By fabricating the structures in the medium, we can control the shape of recorded bits and, in effect, their spatial frequency distribution. We succeeded in recording bits with a 0.5μm interval in any particular plane and 2.0μm interval between successive layers. Thus, storage density of 2.0Tbits∕cm3 is achieved.
Third-order optical autocorrelator for time-domain operationat telecommunication wavelengths
Authors: Ramos-Ortiz G. , Cha M. , Thayumanavan S. , Mendez J. C. , Marder S. R. , Kippelen B.
Published: July 2004

We report on amorphous organic thin films that exhibit efficient third-harmonic generation at telecommunication wavelengths. At 1550nm, micrometer-thick samples generate up to 17μW of green light with input power of 250mW delivered by an optical parametric oscillator. This high conversion efficiency is achieved without phase matching or cascading of quadratic nonlinear effects. With these films, we demonstrate a low-cost, sensitive third-order autocorrelator that can be used in the time-frequency domain.
Effects of chemical composition on the optical properties of Zn1−xCdxO thin films
Authors: Lee Sang Yeol , Li Y. , Lee Jang-Sik , Lee J. K. , Nastasi M. , Crooker S. A. , Jia Q. X. , Kang Hong-Seong , Kang Jeong-Seok
Published: July 2004

Zn 1 − x Cd x O thin films were deposited on (0001) sapphire substrates by pulsed-laser deposition. Structural and optical properties of Zn1−xCdxO films were strongly correlated to the processing conditions. The composition of the films varied nonmonotonically as a function of deposition temperatures due to the difference of vapor pressure between Cd and Zn species. The optical energy bandgap of Zn1−xCdxO thin films, measured by photoluminescence and transmittance, changed from 3.249to3.291eV. The change of the optical properties was mainly attributed to the change of the stoichiometry of Zn1−xCdxO, as determined by Rutherford backscattering spectroscopy.
Highly sensitive photoalignment of liquid crystals through polarization preserved triplet energy transfer
Authors: Furumi Seiichi , Ichimura Kunihiro
Published: July 2004

Highly sensitive photoalignment of liquid crystals (LCs) can be realized by the polarization preserved triplet energy transfer from doped sensitizers to cinnamate side chains of a photocrosslinkable polymer. Linearly polarized irradiation of sensitizer-doped polymer films with 365nm light for selective excitation of the triplet photosensitizer gives rise to azimuthal photodichroism of cinnamates as a result of nanometric triplet energy transfer process preserving the polarization state of triplet-excited photosensitizer. This phenomenon is applicable to the surface-assisted orientational photocontrol of nematic LCs with high performance of extremely low exposure energies.
Investigation of intermittency in simulated and experimental turbulence data by wavelet analysis
Authors: Mahdizadeh N. , Ramisch M. , Stroth U. , Lechte C. , Scott B. D.
Published: July 2004

Turbulent transport in magnetized plasmas has an intermittent nature. Peaked probability density functions and a 1/frequency decay of the power spectra have been interpreted as signs of self-organized criticality generated, similar to a sand pile, by the critical gradients of ion- (ITG) or electron-temperature-gradient (ETG) driven instabilities. In order to investigate the degree of intermittency in toroidally confined plasmas in the absence of critical pressure or temperature gradients, data from the drift-Alfvén-wave turbulence code DALF3 [B. Scott, Plasma Phys. Controlled Fusion 39, 1635 (1997)], running with a fixed background pressure gradient, and from a weakly driven low-temperature plasma are analyzed. The intermittency is studied on different temporal scales, which are separated by a wavelet transform. Simulated and experimental data reproduce the results on intermittent transport found in fusion plasmas. It can therefore be expected that in fusion plasmas, too, a substantial fraction of the bursty nature of turbulent transport is not related to avalanches caused by a critical gradient as generated by ITG or ETG turbulence.
Coupled surface plasmon-polariton mediated photoluminescencefrom a top-emitting organic light-emitting structure
Authors: Wedge S. , Wasey J. A. E. , Barnes W. L. , Sage I.
Published: July 2004

We report strong photoluminescence from a top-emitting organic light-emitting structure where emission takes place through a thin (55nm) silver film. We show that this emission is mediated via coupled surface plasmon-polariton modes. Our results show that the addition of a dielectric grating to otherwise planar structures, such as surface-emitting organic light-emitting diodes, may offer a way to increase the external efficiency of top-emitting organic light-emitting diodes.