bluuebunny/crossref_metadata_2025 huggingface dataset:
Heuristic modeling of spectral plasma emission for laser-induced breakdown spectroscopy
Authors: Wester Rolf , Noll Reinhard
Published: December 2009

A heuristic model was developed to describe the spectral emission of laser-induced plasmas generated for laser-induced breakdown spectroscopy under the assumption that the composition of the plasma and the plasma state is known. The plasma is described by a stationary spherical shell model surrounded by an ambient gas, which partially absorbs the emitted radiation. The radiation transport equation is used to calculate the spectrum emitted by the plasma. Simulations of a multiline iron spectrum and a self-reversed Al line are compared with experimental spectra. For the iron spectrum, the degree of congruence is moderate to good, which may be attributed to a lack of precise atomic and Stark broadening data as well as a simplified plasma model. The line profile of the Al resonance line with self reversal can be simulated with a high degree of agreement. Simulated spectra of a steel sample in the vacuum ultraviolet spectral range demonstrate the strong influence of the ambient atmosphere in the spectral range between 178 and 194 nm. The number of free parameters of the plasma model of 8 can be further reduced down to 3, taking into account the integral parameters of the plasma that are accessible experimentally.
Influence of impurities on the α to ω phase transition in zirconium under dynamic loading conditions
Authors: Rigg P. A. , Greeff C. W. , Knudson M. D. , Gray G. T. , Hixson R. S.
Published: December 2009

Experiments have been carried out to investigate the α to ω phase transition in polycrystalline zirconium (Zr) metal. Samples with three levels of impurities were shock loaded using both gas-driven and powder-driven guns and ramp loaded using magnetic drive to investigate the effects of impurities on the properties of this solid-solid phase transition. Samples were backed by either sapphire or LiF windows and data were obtained using a VISAR to record the particle velocity at the sample/window interface. The results of these experiments showed significant differences in both the transition stress and kinetics for samples with different impurity levels demonstrating that impurities play an important role in the transformation mechanism in zirconium.
Magnetic phase coupled to an electric memory state in d oxide ZrO2 films
Authors: Jo Y. , Hwang I. R. , Park B. H. , Lee K. J. , Lee S. I. , Jung M. H.
Published: December 2009

It is quite interesting to develop a multifunctional device using a single material with a simple structure. One of the possible candidates could be multiferroics, which are both ferroelectric and magnetic. By taking advantage of the strong spin-charge coupling, the electric field can control the magnetic polarization and the magnetic field can control the electric polarization. However, these multiferroics are not yet attractive for practical applications because none of the existing materials combine large and robust electric and magnetic polarizations at room temperature. Here, we report an unusual functional material showing a magnetic phase strongly coupled to an electric memory state at room temperature. An oxygen-vacant ZrO2 thin film generates bistable resistive switching between high-resistance (HR) and low-resistance (LR) states by applying external voltage, and it is ferromagnetic at the HR state but nonmagnetic at the LR state. This unique feature is applicable to unusual functional devices, such as electric-field-controlled magnetic data storage devices.
High performance nanocomposite thin film transistors with bilayer carbon nanotube-polythiophene active channel by ink-jet printing
Authors: Hsieh Gen-Wen , Li Flora M. , Beecher Paul , Nathan Arokia , Wu Yiliang , Ong Beng S. , Milne William I.
Published: December 2009

Nanocomposite thin film transistors (TFTs) based on nonpercolating networks of single-walled carbon nanotubes (CNTs) and polythiophene semiconductor [poly[5,5′-bis(3-dodecyl-2-thienyl)-2,2′-bithiophene] (PQT-12)] thin film hosts are demonstrated by ink-jet printing. A systematic study on the effect of CNT loading on the transistor performance and channel morphology is conducted. With an appropriate loading of CNTs into the active channel, ink-jet printed composite transistors show an effective hole mobility of 0.23 cm2 V−1 s−1, which is an enhancement of more than a factor of 7 over ink-jet printed pristine PQT-12 TFTs. In addition, these devices display reasonable on/off current ratio of 105–106, low off currents of the order of 10 pA, and a sharp subthreshold slope (<0.8 V dec−1). The work presented here furthers our understanding of the interaction between polythiophene polymers and nonpercolating CNTs, where the CNT density in the bilayer structure substantially influences the morphology and transistor performance of polythiophene. Therefore, optimized loading of ink-jet printed CNTs is crucial to achieve device performance enhancement. High performance ink-jet printed nanocomposite TFTs can present a promising alternative to organic TFTs in printed electronic applications, including displays, sensors, radio-frequency identification (RFID) tags, and disposable electronics.
Charge transport and trapping in InN nanowires investigated by scanning probe microscopy
Authors: Liu Jie , Cai Zhihua , Koley Goutam
Published: December 2009

Charge transport and trapping in InN nanowires (NWs) and their networks have been investigated using scanning current voltage microscopy (SIVM) and scanning gate microscopy (SGM). SIVM maps indicate highly conducting NWs and nanojunctions as well as significant variation in surface barrier height along the NWs, which are strongly affected by deformations. SIVM measurements were used to determine the electrical conductivity and carrier mobility of individual NWs exploiting the unusually large probe current under reverse bias, arising out of possible type II heterostructure band alignment. Strong correlation between surface barrier change and electrical conductivity of the NW was observed, which can be explained by considering a high density of electron accumulation at the NW surface. SGM measurements performed on NW field effect transistors reveal large scale trapping of carriers under reverse bias, while cyclic drain current-probe voltage measurements indicate both trapping and detrapping rates to be strongly dependent on the magnitude of the reverse bias. Application of a negative probe bias pulse resulted in a drain current recovery transient with time constant of tens of seconds indicating large activation energy for the traps whose density is estimated to be in excess of 2×1013 cm−2.
Analysis of the influence of stress signal frequency on fatigue of ferroelectric thin films
Authors: Poullain G. , Cibert C. , Bouregba R.
Published: December 2009

The fatigue properties of (111) oriented PbZr0.6Ti0.4O3 thin films have been studied as a function of stress signal frequency (f). The results were analyzed in the framework of the model based on trapping and releasing of carriers in band gap states located at the surfaces between electrodes and ferroelectric film (“surface state model”). The time constants of trapping and releasing of carriers, which govern the variation of the remnant polarization (Pr) as a function of the cycle number (N), were determined in agreement with classical results obtained in characterization of metal-oxide semiconductors structures. In spite of the wide variety in the shapes of Pr(N) curves obtained as a function of the frequency, experimental data have been well fitted by the model. These results confirm the soundness of the surface state model for the description of fatigue in ferroelectric thin films.
Probing diagonal laser transitions in InGaAs/AlInAs/InP quantum cascade lasers
Authors: Soulby M. R. , Revin D. G. , Commin J. P. , Krysa A. B. , Roberts J. S. , Cockburn J. W.
Published: December 2009

We report on the midinfrared broadband transmission spectroscopy measurements of a λ∼4.3 μm strain compensated In0.64Ga0.36As/Al0.58In0.42As/InP quantum cascade laser. A detailed experimental analysis of the electronic distribution for bias values below the laser threshold is presented, highlighting the effects of the design with strongly diagonal laser transition. A marked voltage induced Stark shift is observed for the diagonal laser transition while the vertical intersubband transitions involved higher energy levels remained nearly bias independent. We also demonstrate the direct observation of intersubband transitions originating from the ground level of the injector miniband to the level confined above the AlInAs barriers.
Nanopolar structures and local ferroelectricity of Sr0.61Ba0.39Nb2O6 relaxor crystal across Curie temperature by piezoresponse force microscopy
Authors: Liu X. Y. , Liu Y. M. , Takekawa S. , Kitamura K. , Ohuchi F. S. , Li J. Y.
Published: December 2009

Nanopolar structures and local ferroelectricity of Sr0.61Ba0.39Nb2O6 relaxor crystal across Curie temperature have been investigated using piezoresponse force microscopy (PFM). The short-range nanopolar clusters are dominated by long-range ferroelectric order at room temperature, but exhibit themselves at higher temperature through the morphology change in written ferroelectric domains and persisting piezoresponse beyond Curie point. A maximum piezoresponse is observed at 80 °C, which is attributed to the peak in the dielectric permittivity near the ferroelectric phase transition. Substantial asymmetry in PFM hysteresis emerges above Curie temperature, indicating an internal bias field that becomes notable in the absence of long-range ferroelectric order.
Charge trapping and detrapping in polymeric materials
Authors: Chen George , Xu Zhiqiang
Published: December 2009

Space charge formation in polymeric materials can cause some serious concern for design engineers as the electric field may severely be distorted, leading to part of the material being overstressed. At the worst, this may result in material degradation and possibly premature failure. It is therefore important to understand charge generation, trapping, and detrapping processes in the material. In the present paper, the characteristics of charge trapping and detrapping in low density polyethylene under dc electric field have been investigated using the pulsed electroacoustic technique. It has been found that the charge decay shows very different characteristics for the sample with different periods of electric field application. To explain the results a simple trapping and detrapping model based on two trapping levels has been proposed. Qualitative analysis revealed the similar features to those observed experimentally.
Quantum transport in alkane molecular wires: Effects of binding modes and anchoring groups
Authors: Sheng W. , Li Z. Y. , Ning Z. Y. , Zhang Z. H. , Yang Z. Q. , Guo H.
Published: December 2009

Effects of binding modes and anchoring groups on nonequilibrium electronic transport properties of alkane molecular wires are investigated from atomic first-principles based on density functional theory and nonequilibrium Green’s function formalism. Four typical binding modes, top, bridge, hcp-hollow, and fcc-hollow, are considered at one of the two contacts. For wires with three different anchoring groups, dithiol, diamine, or dicarboxylic acid, the low bias conductances resulting from the four binding modes are all found to have either a high or a low value, well consistent with recent experimental observations. The trend can be rationalized by the behavior of electrode-induced gap states at small bias. When bias increases to higher values, states from the anchoring groups enter into the bias window and contribute significantly to the tunneling process so that transport properties become more complicated for the four binding modes. Other low bias behaviors including the values of the inverse length scale for tunneling characteristic, contact resistance, and the ratios of the high/low conductance values are also calculated and compared to experimental results. The conducting capabilities of the three anchoring groups are found to decrease from dithiol, diamine to dicarboxylic-acid, largely owing to a decrease in binding strength to the electrodes. Our results give a clear microscopic picture to the transport physics and provide reasonable qualitative explanations for the corresponding experimental data.
Competition between current-induced excitation and bath-induced decoherence in molecular junctions
Authors: Jorn Ryan , Seideman Tamar
Published: December 2009

A general framework is presented to describe a resonant inelastic current inducing dynamics in the nuclear degrees of freedom of a molecule embedded between two electrodes. This approach makes use of the scattering theory of density matrices to account for the interaction between the scattering charge and the molecular modes to all orders and reduces in appropriate limits to both the standard master equation treatment for vibrational heating and the Landauer formalism for purely elastic transport. While the method presented here is equivalent to these approaches in limiting cases, it also goes well beyond their restrictions by incorporating the full quantum dynamics in the vibrational subspace in the presence of tunneling current. By application to the Au–C60–Au junction, it is shown that inclusion of vibrational coherences, which were previously neglected, is crucial to accurately predict the dynamics induced by current in molecular devices. Interaction with a bath of phonon modes is incorporated within the Bloch model and the competition between the bath-induced relaxation processes and the current-induced excitation is studied in detail over a range of temperatures.
Rayleigh surface wave in a piezoelectric wafer with subsurface damage
Authors: Cao Xiaoshan , Jin Feng , Jeon Insu
Published: December 2009

An analytical study is carried out on the propagation of Rayleigh surface waves in a piezoelectric wafer with subsurface damage. The region of subsurface damage is considered to be a functionally graded piezoelectric thin film. The findings show the influence of the gradient parameter, thickness of the region of subsurface damage, and three different types of damage on the properties of surface-wave propagation, including the phase velocity and electromechanical coupling factor. They can provide theoretical guidance in nondestructive evaluation for the analysis of the reliability and durability of electronic devices made of piezoelectric wafers.
Influence of gravity on collisions of monodispersed droplets in homogeneous isotropic turbulence
Authors: Onishi Ryo , Takahashi Keiko , Komori Satoru
Published: December 2009

This paper studies the gravity influence on collisions of monodispersed droplets in homogeneous isotropic turbulence by means of direct numerical simulations (DNSs). The DNS results show that, in certain Stokes and Reynolds regimes, collision frequencies are significantly reduced in the presence of gravity. Those decreases are mainly attributable to the decrease in the droplet relative velocity, since the change in radial distribution function—often referred to preferential concentration—is small. Further analysis of the results reveals that droplet sedimentation due to gravity shortens the droplet-fluid interaction time, consequently weakening the relative motions between droplets. These observations lead to an analytical model that can be used to estimate the velocity fluctuations of sedimenting particles under gravity. Utilizing this model, we constructed a further analytical model for estimating the gravitational influence on collisions. Given flow and particle parameters, the model calculates the ratio of collision frequencies with and without the effect of gravity. Past studies simply noted that the gravitational influence is negligible when the droplet sedimenting velocity is much smaller than the flow velocity fluctuations. Our analytical model further suggests that the gravitational influence on collisions of monodispersed cloud droplets with non-negligible sedimentation rates stays negligibly small even in high Reynolds number flows, such as those typically found in convective clouds.
Resistance to edge recombination in GaAs-based dots-in-a-well solar cells
Authors: Gu Tingyi , El-Emawy Mohamed A. , Yang Kai , Stintz Andreas , Lester Luke F.
Published: December 2009

Insensitivity to edge recombination is observed in GaAs-based InAs/InGaAs quantum dots-in-a-well (DWELL) solar cells by comparing its current-voltage (IV) plot to GaAs control samples. The edge recombination current component is extracted by analyzing devices of different areas and then compared to DWELL cells of comparable dimensions. The results demonstrate that GaAs-based solar cells incorporating a DWELL design are relatively insensitive to edge recombination by suppressing lateral diffusion of carriers in the intrinsic layer, and thus promising for applications that require small area devices such as concentration or flexible surfaces.
Probing of carrier behavior in organic electroluminescent diode using electric field induced optical second-harmonic generation measurement
Authors: Taguchi Dai , Weis Martin , Manaka Takaaki , Iwamoto Mitsumasa
Published: December 2009

By using the electric field induced optical second-harmonic generation (EFISHG) measurements, we probed the transient electric field in a double-layer indium zinc oxide (IZO)/N, N′-di-[(1-naphthyl)-N,N′-diphenyl]-(1,1′-biphenyl)-4, 4′-diamine(α-NPD)/tris(8-hydroxy-quinolinato)aluminum(III) (Alq3)/Al electroluminescent (EL) diode. Results evidently showed that EL was initiated by the injected hole transport across α-NPD layer, and holes accumulated at the α-NPD/Alq3 interface while EL was enhanced. Analysis based on the Maxwell–Wagner effect model well accounted for the hole accumulation. EFISHG measurement is useful as a tool for probing carrier behavior in organic EL devices.
Analysis of anisotropic local field in sum frequency generation spectroscopy with the charge response kernel water model
Authors: Ishiyama Tatsuya , Morita Akihiro
Published: December 2009

A new flexible and polarizable water model based on the charge response kernel (CRK) theory is developed for the analysis of sum frequency generation (SFG) spectroscopy. The CRK model well describes several bulk water properties and SFG spectrum by molecular dynamics (MD) calculations. While the flexible and polarizable MD simulation generally adopts the short-range damping of intermolecular interaction, it is found that the same procedure is not adequate for the calculation of transition dipole in strongly hydrogen bonding environment. Accordingly, the improved calculation of the nonlinear susceptibility of water surface results in the positive imaginary part in the 3000–3200 cm−1 region, which is consistent with recent phase-sensitive experiments. The mechanism of the positive region is attributed to the anisotropic local field effect induced by the orientational correlation of surface water.
Enhancement in transition temperature and upper critical field of CeO0.8F0.2FeAs by yttrium doping
Authors: Prakash J. , Singh S. J. , Banerjee A. , Patnaik S. , Ganguli A. K.
Published: December 2009

We report significant enhancement in superconducting properties of yttrium substituted Ce1−xYxOFFeAs superconductors. The polycrystalline samples were prepared by two step solid state reaction technique. X-ray diffraction confirmed tetragonal ZrCuSiAs structure with decrease in both a and c lattice parameters on increasing yttrium substitution (with fixed F content). With smaller ion Y in place of Ce, the transition temperature increased by 6 K. Yttrium doping also lead to higher critical fields as well as broader magnetization loops, particularly at elevated temperature.
Changes in VO2 band structure induced by charge localization and surface segregation
Authors: Chen Changhong , Fan Zhaoyang
Published: December 2009

Vanadium vacancies introduce acceptor doping with hole localization, while oxygen vacancies cause electron localization and donor doping. As deposition temperature increases, donor concentration stays constant, whereas acceptor concentration significantly increases, leading to enhanced (011) lattice-plane compression and surface segregation. Localized charges result in shifts of O 1s and V4+ 2p core levels toward higher binding energies, and O 2p and V4+ 3d valence bands toward the Fermi level, but egπ bands lifting and a1g bands splitting energies are both insensitive to charge localization. Particularly, band-gap energy decreases with increasing V–V pair distance, and is significantly reduced by band tailing.
Capacitance-voltage and current-voltage characteristics of graphite oxide thin films patterned by ultraviolet photolithography
Authors: Lee In-yeal , Kannan E. S. , Kim Gil-Ho
Published: December 2009

Electrical characteristics of graphite oxide (GO) thin films deposited on a p-type silicon substrate were investigated to explore its potential application as a dielectric material in organic field effect transistors. Channel current in the GO films exhibited linear response with the applied bias in the positive voltage regime and increased exponentially for negative source-drain bias. This rectifying behavior arises due to the Coulombic interaction between the electrons emitted from the metal contact and the space charge region in the GO film. A clockwise hysteresis loop was observed in the capacitance-voltage characteristics due to the presence of traps at the interface.
Nanoscale phase separation of a binary molecular system of copper phthalocyanine and di-indenoperylene on Ag(111)
Authors: Huang Han , Huang Yuli , Pflaum Jens , Wee Andrew Thye Shen , Chen Wei
Published: December 2009

Alternating copper phthalocyanine (CuPc) and di-indenoperylene (DIP) molecular chain arrays have been fabricated via nanoscale phase separation of this CuPc:DIP binary molecular system on Ag(111). In situ low-temperature scanning tunneling microscopy has been used to investigate the molecular self-assembling processes on surface and the structural property of the well-ordered nanostructure arrays. The results show that the formation of these supramolecular structures is governed by the noncovalent molecule-molecule interactions.
Iloprost, a prostacyclin analogue, stimulates meiotic maturation and early embryonic development in pigs
Authors: Kim Ji-Su , Chae Jung-Il , Song Bong-Seok , Lee Kyu-Sun , Choo Young-Kug , Chang Kyu-Tae , Park Humdai , Koo Deog-Bon
Published: January 2010

Oviduct fluid contains various cytokines and growth factors that enhance the embryo development during the preimplantation period. In hatched embryos, prostacyclin (PGI2) improves implantation, but its role during oocyte maturation and early embryo development remains contentious. Therefore, in the present study, we examined the effects of a PGI2 analogue (iloprost) on meiotic maturation and early embryonic development in pigs, as well on the structural integrity, mitochondrial membrane potential and apoptosis in blastocysts. First, meiotic maturation in pig oocytes was examined in the presence of increasing concentrations of iloprost (1, 5 and 10 μM). After IVM, a higher proportion of iloprost-treated compared with untreated oocytes was in MII (90.0% v. 65.7%, respectively; P < 0.05). In addition, protein kinase A activity increased in iloprost-treated oocytes, indicating increased intracellular cAMP concentrations. After 22 h iloprost treatment (44 h total incubation time), western blotting demonstrated increased expression of extracellular signal-regulated kinase (ERK) 1/2, phosphorylated (p-) ERK1/2, cAMP response element-binding protein (CREB), p-CREB and cyclo-oxygenase-2, indicating activation of the mitogen-activated protein kinase and PGI2 pathways. In addition, the frequency of polyspermy decreased in iloprost-treated oocytes (19.9%) compared with control (35.8%), whereas the rate of blastocyst formation increased (P < 0.05). Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) showed that the number of nuclei containing fragmented DNA at the blastocyst stage decreased in the iloprost-treated group compared with control (1.2% v. 3.6%, respectively). In conclusion, iloprost appears to play a direct role in porcine oocyte maturation by enhancing blastocyst structure and survival.
Suppression of keratin 18 gene expression in bovine blastocysts by RNA interference
Authors: Goossens Karen , Tesfaye Dawit , Rings Franca , Schellander Karl , Hölker Michael , Van Poucke Mario , Van Zeveren Alex , Lemahieu Isabel , Van Soom Ann , Peelman Luc J.
Published: January 2010

The expression of the cytoskeleton protein Keratin 18 (KRT18) starts at the onset of bovine blastocyst formation. KRT18 is solely expressed in the trophectoderm and can therefore be used as a marker for trophectodermal differentiation. In the present study, the expression of KRT18 was suppressed by RNA interference to probe its functional importance in bovine blastocyst formation. Microinjection of KRT18 double-stranded RNA into the cytoplasm of zygotes resulted in reduced KRT18 mRNA (76% reduction) and protein expression at the blastocyst stage and a lower developmental competence (41% reduction in the percentage of blastocyst formation) compared with non-injected and phosphate-buffered saline (PBS)-injected controls. KRT18 downregulation was associated with reduced mRNA expression of KRT8, the binding partner of KRT18, but had no effect on the expression of KRT19, CDH1 and DSP, other genes involved in intermediate filament and cytoskeleton formation. The results of the present study demonstrated that KRT18 knockdown in preimplantation embryos results in reduced blastocyst formation, but no further morphological aberrations were observed with regard to the biological function of KRT18. These observations could be due to the function of KRT18 being replaced by that of another gene, the surviving blastocysts expressing the minimum level of KRT18 required for normal blastocyst development or the possibility that further aberrations may occur later in development.
Neuregulin 1 regulates pyramidal neuron activity via ErbB4 in parvalbumin-positive interneurons
Authors: Wen Lei , Lu Yi-Sheng , Zhu Xin-Hong , Li Xiao-Ming , Woo Ran-Sook , Chen Yong-Jun , Yin Dong-Min , Lai Cary , Terry Alvin V. , Vazdarjanova Almira , Xiong Wen-Cheng , Mei Lin
Published: December 2009

Neuregulin 1 (NRG1) is a trophic factor thought to play a role in neural development. Recent studies suggest that it may regulate neurotransmission, mechanisms of which remain elusive. Here we show that NRG1, via stimulating GABA release from interneurons, inhibits pyramidal neurons in the prefrontal cortex (PFC). Ablation of the NRG1 receptor ErbB4 in parvalbumin (PV)-positive interneurons prevented NRG1 from stimulating GABA release and from inhibiting pyramidal neurons. PV-ErbB4
−/−
mice exhibited schizophrenia-relevant phenotypes similar to those observed in NRG1 or ErbB4 null mutant mice, including hyperactivity, impaired working memory, and deficit in prepulse inhibition (PPI) that was ameliorated by diazepam, a GABA enhancer. These results indicate that NRG1 regulates the activity of pyramidal neurons by promoting GABA release from PV-positive interneurons, identifying a critical function of NRG1 in balancing brain activity. Because both NRG1 and ErbB4 are susceptibility genes of schizophrenia, our study provides insight into potential pathogenic mechanisms of schizophrenia and suggests that PV-ErbB4
−/−
mice may serve as a model in the study of this and relevant brain disorders.
Nucleus accumbens dopamine mediates amphetamine-induced impairment of social bonding in a monogamous rodent species
Authors: Liu Yan , Aragona Brandon J. , Young Kimberly A. , Dietz David M. , Kabbaj Mohamed , Mazei-Robison Michelle , Nestler Eric J. , Wang Zuoxin
Published: December 2009

The prairie vole (
Microtus ochrogaster
) is a socially monogamous rodent species that forms pair bonds after mating, a behavior in which central dopamine (DA) has been implicated. Here, we used male prairie voles to examine the effects of drug exposure on pair bonding and related neural circuitry. In our first experiment, amphetamine (AMPH) motivated behavior was examined using a conditioned place preference (CPP) paradigm and was shown to be mediated by activation of D1-like DA receptors. Next, we examined the effects of repeated AMPH exposure on pair bonding. Intact and saline pretreated control males displayed mating-induced partner preferences, whereas males pretreated with AMPH at the doses effective to induce CPP failed to show mating-induced partner preferences. Such AMPH treatment also enhanced D1, but not D2, DA receptor expression in the nucleus accumbens (NAcc). Furthermore, pharmacological blockade of D1-like DA receptors in the NAcc rescued mating-induced partner preferences in AMPH-treated males. Together, our data indicate that repeated AMPH exposure may narrow the behavioral repertoire of male prairie voles via a DA receptor-specific mechanism in the NAcc, resulting in the impairment of pair bond formation.
De l’Achmetis Oneirocriticon au Somniale Danielis français, ou comment la hyène devint truie
Authors: Birrer Larissa
Published: December 2009

L’Achmetis Oneirocriticon, composé en grec à Byzance autour du Xe siècle, est arrivé de manière plus ou moins intacte dans l’Occident du XIIIe/XIVe siècle. Ce sont, dans l’ensemble, presque les mèmes images oniriques, dans un ordre très proche et véhiculant à peu près la même signification qui circulent désormais sous un autre nom, le Somniale Danielis, en latin et en français. La présene contribution se propose d’étudier les modifications qui interviennent au cours de cette transposition géographique et culturelle, à l’aide d’un échantillon de textes pris dans la partie consacrée aux animaux.
Les animaux dans l’Ésope de Julien Macho
Authors: Laneville Charles
Published: December 2009

En 1480, Julien Macho traduit en français la version bilingue latin-allemand des fables d’Ésope faite par Heinrich Steinhöwel quelques années auparavant. L’auteur lyonnais offre ainsi au public français la compilation de fables la plus volumineuse du Moyen Âge français. Ce présent étudie un des éléments constitutifs du genre, les personnages animaliers, en comparant la typologie des animaux à l’oeuvre dans le recueil de Macho à celle des autres traductionsadaptations de la tradition ésopique française, les Isopets. Trois fables sont analysées plus précisément, qui partagent une même situation centrale, celle d’un animal qui prend l’apparence d’un autre mais finit par être démasqué. L’image de l’âne dans les fables est également placée sous un regard nouveau. On remarque alors une grande constance dans les caractéristiques animalières véhiculées à travers les recueils de fables en langue française pendant le Moyen Âge.
L’anguille dans les textes scientifiques et littéraires médiévaux
Authors: Cornec Cécile Le
Published: December 2009

L’anguille a dans la culture médiévale un statut ambivalent: les oeuvres scientifiques invitent à s’en méfier, alors que les livres de cuisine la mettent à l’honneur. à l’instar de sa cousine serpentine la lamproie, l’anguille occupe également une place de choix dans la littérature. Elle suscite la convoitise effrénée des gourmands, notamment dans la fameuse branche du Roman de Renart. Dans ce texte, comme dans le fabliau Les Trois Dames qui troverent l’anel, l’anguille apparaît aussi comme l’instrument idéal du piège tendu par un fourbe ingénieux. Que signifie le choix de cette espèce? Nous nous demandons ici comment les pratiques et les représentations médiévales relatives à l’anguille permettent d’éclairer son rôle narratif et symbolique dans ces textes littéraires. De Hildegarde de Bingen aux régimes de santé du xiv
e siècle, en passant par les encyclopédistes dominicains du xiii
e siècle, les savants médiévaux dressent de l’anguille un portrait peu amène: animal hybride, trop lié à la terre pour être un véritable poisson, elle fournit une nourriture malsaine tant que ses propriétés n’ont pas été amendées par l’art culinaire. Dans le fabliau Les Trois Dames qui troverent l’anel, le choix de l’anguille semble obéir surtout à un souci réaliste, même si d’éventuelles connotations sexuelles ne sont pas à exclure. Quant aux anguilles qui servent d’appât à Renart pour piéger Isengrin, elles apparaissent d’abord comme les poissons de la gula, l’aliment “maigre” chéri des goinfres hypocrites.
Aquatic animals in the Catalan Bestiari
Authors: Martín Llúcia
Published: December 2009

Before entering into the main study on aquatic animals included in Catalan bestiary texts, a brief summary is presented on the history of preserved Catalan texts that contain a bestiary: a list of real or imaginary animals with their characteristics and corresponding symbolic reference. The aquatic animals present in the Catalan bestiary are the frog, the sawfish, the whale; we also consider a hybrid, the mermaid, and the crocodile, an animal which is not a fish but is closely linked with the aquatic environment. In many cases we can speak about textual coincidences with different traditions, from Latin Physiologi to medieval European texts. Peculiarities of the Catalan version are studied in connexion with the Tuscan tradition.
The fish section in Engelbert of Admont’s Tractatus de naturis animalium (ca. 1250–1331)
Authors: Schmitz Max
Published: December 2009

Engelbert’s unedited work on animals is delivered to posterity in a limited number of manuscripts. The second part of the treatise that is discussed here closely follows the structure of Isidore of Seville’s encyclopaedia. In order to illustrate Engelbert’s work method and the emphasis of this part, the article focuses on the fourth category (de piscibus) which is an interesting section for a number of reasons. The main sources are specified and the text is compared to similar writings. Finally the edition of ten chapters out of 53 from this section completes the study. Born in Styria in the middle of the 13th century, Engelbert entered the Benedictine abbey of Admont as a teenager. Most facts of his life are related in his autobiographical letter written to his friend Ulric of Vienna. According to the letter he left the abbey for Prague in 1271, where he studied grammar and logic at the cathedral school. Political troubles caused by the election of Rudolph I for Roman king in October 1273, forced him to leave Bohemia one year later. Engelbert then returned to Admont for a short time; then decided to complete his education in Padua. There, he studied the liberal arts for five years (around 1276–1281) followed by theology for four more years at the Dominican monastery of St. Augustine. He then returned to Admont before being elected abbot of St. Peter in Salzbourg. He remained the head of the mother abbey of Admont for eleven years. In 1297, the abbot of Admont, Henri II, was murdered and Engelbert was chosen to replace him. He ruled the abbey for 30 years until 1327, when he resigned and retired. Four years later he died.
Le Roman de Renart et la fable de l’Aigle et du Serpent
Authors: Slerca Anna
Published: December 2009

La fable ésopique du l’Aigle et du Renard trouve son homologue dans une fable mésopostamienne du XVIIe siècle avant notre ère, en caractère cunéiformes. Il s’agit de la fable de l’Aigle et du Serpent, qui fait partie d’un texte d’une certaine ampleur, la légende d’Etana. L’intérêt d’une étude comparative à ce sujet réside dans le fait que la fable en question traite entre autres quelques motifs qui ne se rencontrent pas chez Ésope dans ce cas-ci, mais qui font partie du contenu du Roman de Renart. Dans le texte mésopotamien, en effet, nous voyons que le serpent, pour se venger de l’aigle qui a rompu le pacte d’amitié, obtient du dieu du Soleil de pouvoir dresser une embûche à son rival. L’aigle est pris au piège, et il adresse à son tour une prière à la divinité, qui lui permet de se libérer. Dans le Roman de Renart, le goupil ayant offensé Isengrin, ce dernier fait un appel à l’autorité, et ce motif est relié à une embûche dont Renard est la victime, avec la complicité du chien Roonel. Bien entendu, il n’est pas question d’établir forcément un rapport direct entre le texte français et la fable orientale. Il s’agit plutôt de mettre en évidence l’appartenance possible à un groupe de contes, à une tradition qui n’est pas très éloignée. D’autres fables antiques traitent quelques-uns des motifs en question: en particulier, les fables ésopiques de l’Aigle et de l’Escarbot et de l’Homme et du Serpent.
Hidden compartments in AVMs — A new concept
Authors: Pellettieri L. , Svendsen P. , Wikholm G. , Carlsson C.-A.
Published: January 2010

Purpose: The concept of hidden compartments in cerebral arteriovenous malformations (AVMs), which is hereby launched, offers a new explanation for the neurosurgical and neuroradiological controversies concerning patients with AVMs.

Material and Methods: Three patients who were considered completely cured of their AVMs, subsequently developed new areas of malformed vessels as revealed by later angiograms.

Results: These 3 cases support our hidden compartment hypothesis and are reported on here, illustrated with relevant angiograms. The clinical implications of the hidden compartment concept refer to phenomena such as AVM growth, AVM recurrence after surgical excision, irradiation or embolization as well as per- or postoperative hemorrhage and swelling.

Conclusion: The incidence of hidden compartments in the AVM population is unknown but further studies, particularly in the realm of superselective embolization, could reveal their presence.
An iodinated lipid emulsion for CT of the liver
Authors: Bergman A. , Sundin A. , Magnusson A.
Published: January 2010

Purpose: The iodinated hepatocyte-specific lipid emulsion FP 736-03 for CT of the liver was tested against the conventional water-soluble contrast agent iohexol.

Material and Methods: A nude rat model of experimental multiple hepatic metastases from a human colonic cancer was used. The animals were examined 3 weeks after intraportal tumor cell injection. Native examination, and iohexol- and FP-736-03-enhanced CT were performed. The detection rate was determined on a lesion-by-lesion basis. Metastatic diameters measured on CT images were compared with corresponding macroscopic serial liver specimens.

Results: In a lesion-by-lesion analysis of 140 metastases, the detection rates for 2 viewers were 16.4% and 30.7% for native examination, 12.9% and 17.9% for iohexol-enhanced CT, and 53.6% and 72.1 % for FP-736-03-enhanced CT, respectively. The detection rates tended to increase with lesion diameter.

Conclusion: The hepatocyte-specific contrast medium FP 736-03 improved the detection rate significantly in comparison with both native and iohexol-enhanced CT.
Renal CT after intravenous injection of nonionic dimeric or nonionic monomeric contrast media in healthy volunteers
Authors: Rasmussen F. , Lindequist S. , Nielsen S. Møller , Bjartveit K.
Published: January 2010

Purpose: To establish and compare time-density curves of the aorta, vena cava and renal cortex, medulla and pelvis after injection of the nonionic dimer iodixanol or the nonionic monomer iopromide contrast media.

Material and Methods: In 36 healthy volunteers CT at the renal hilus was performed at regular intervals before and until 30 min after injection of 13.5 g I iodixanol or 15.0 g I iopromide. The density of the renal cortex, medulla, pelvis, aorta and inferior caval vein was measured.

Results: With injection of the 10% lower iodine dose in the iodixanol group, the profiles of the CT time-density curves were similar for all regions except for the renal pelvis. For the renal pelvis, significantly higher density values were obtained for the iodixanol group up to 10 min after injection.

Conclusion: Although the present study shows that a lower iodine dose is needed for a dimeric compared to a monomeric nonionic contrast medium to obtain similar time-density curves, more studies are needed to establish the clinical importance of this for urography.
Addition of methyl cellulose enema to double-contrast barium imaging of sigmoid diverticulosis
Authors: Olsson R. , Adnerhill I. , Björkdahl P. , Ekberg O. , Fork F. T.
Published: January 2010

Double-contrast barium enema has a reduced sensitivity in patients with severe sigmoid diverticulosis. Therefore a carboxy methyl cellulose enema was employed after the conventional double-contrast examination in 15 patients with sigmoid diverticulosis. A significant increase in lumen diameter and a superior removal of barium residue from the diverticulas facilitated the interpretation of the sigmoid loops.

Conclusion: The addition of methyl cellulose enema to double-contrast barium imaging improves diagnostic imaging in diverticulosis by expanding the lumen and emptying the diverticulas.
Association of midoesophageal diverticula with oesophageal motor disorders
Authors: Schima W. , Schober E. , Stacher G. , Franz P. , Uranitsch K. , Pokieser P. , Wenzl E. , Resch A. , Herold C. J.
Published: January 2010

Purpose: To evaluate the prevalence and clinical significance of associated oesophageal motor disorders in patients with midoesophageal diverticula.

Material and Methods: We retrospectively reviewed videofluoroscopic and, if available, manometric studies of 30 patients with midoesophageal diverticula. The type of diverticulum and the presence and nature of oesophageal motor disorders were assessed.

Results: Videofluoroscopy showed that 24 patients had 26 pulsion-type diverticula and 6 patients had 7 traction-type diverticula. Oesophageal motor disorders were demonstrated in 21 of the 24 patients with pulsion-type diverticula and in 3 of the 6 with traction-type diverticula. Nineteen patients had nonspecific motor disorders, 5 had achalasia, and 5 had gastrooesophageal reflux or oesophagitis.

Conclusion: Midoesophageal diverticula are most often of the pulsion-type and tend to be associated with an oesophageal motor disorder. Motor disorders are predominantly nonspecific, but achalasia may be encountered as well.
CT findings at lupus mesenteric vasculitis
Authors: Ko S.F. , Lee T.-Y. , Cheng T.-T. , Ng S.-H. , Lai H.-M. , Cheng Y.-F. , Tsai C.-C.
Published: January 2010

Purpose: To describe the spectrum of early CT findings of lupus mesenteric vasculitis (LMV) and to assess the utility of CT in the management of this uncommon entity.

Methods: Abdominal CT was performed within 1–4 days (average 2.2 days) of the onset of severe abdominal pain and tenderness in 15 women with systemic lupus erythematosus. Prompt high-dose i.v. corticosteroid was administered in 11 patients after the CT diagnosis of LMV was made. CT was performed after abdominal symptoms subsided.

Results: Eleven cases revealed CT features suggestive of LMV including conspicuous prominence of mesenteric vessels with palisade pattern or comb-like appearance (CT comb sign) supplying focal or diffuse dilated bowel loops (n=11), ascites with slightly increased peritoneal enhancement (n=11), small bowel wall thickening (n=10) with double halo or target sign (n=8). Follow-up CT before high-dose steroid therapy revealed complete or marked resolution of the abnormal CT findings.

Conclusion: CT is helpful for confirming the diagnosis of LMV, especially the comb sign which may be an early sign. Bowel ischemia due to LMV is less ominous than previously expected, and the abnormal CT findings were reversible when early diagnosis and prompt i.v. steroid therapy could be achieved.
Chronic post-traumatic pseudoaneurysm of the abdominal aorta diagnosed by duplex doppler ultrasonography
Authors: Llorente J. Gonzalez , Gallego M. Galindo , Arnaiz A. Martinez
Published: January 2010

Traumatic pseudoaneurysm of the abdominal aorta is a rare pathology. To date aortography, CT and ultrasonography are the only diagnostic tools available for establishing the diagnosis. We report a case in which the presence of a continuous bidirectional flow in the neck of the pseudoaneurysm, as seen with duplex Doppler ultrasonography, confirmed the diagnosis.
Proliferative response in smooth muscle cells after angioplasty or insertion of self-expanding stents
Authors: Cwikiel W. , Harnek J. , Zoucas E. , Stenram U.
Published: January 2010

Purpose: Evaluation of the early proliferative reaction of smooth muscle cells (SMC) in the media of the artery following percutaneous transluminal angioplasty (PTA), compared with the reaction on insertion of self-expandable stents.

Material and Methods: In 6 healthy pigs, one iliac artery was overdilated with an 8-mm diameter angioplasty balloon. A self-expanding Nitinol stent, OD 8 mm, was inserted into the contralateral iliac artery without previous dilatation. The nuclei of the proliferating SMC in the media of the artery were labelled by intravenous administration of 5-bromo-2-deoxy-uridine and cells in S-phase counted 24 h after the procedure.

Results: The mean number of proliferating nuclei of the SMC increased significantly more after PTA (p<0.05) than after the insertion of a stent.

Conclusion: Early proliferative reaction of the SMC is more pronounced after PTA than after insertion of the self-expanding stent.
An independent software system for the analysis of dynamic MR images
Authors: Torheim G. , Lombardi M. , Rinck P. A.
Published: January 2010

Purpose: A computer system for the manual, semi-automatic, and automatic analysis of dynamic MR images was to be developed on UNIX and personal computer platforms. The system was to offer an integrated and standardized way of performing both image processing and analysis that was independent of the MR unit used.

Material and Methods: The system consists of modules that are easily adaptable to special needs. Data from MR units or other diagnostic imaging equipment in techniques such as CT, ultrasonography, or nuclear medicine can be processed through the ACR-NEMA/DICOM standard file formats. A full set of functions is available, among them cine-loop visual analysis, and generation of time-intensity curves., Parameters such as cross-correlation coefficients, area under the curve, peak/maximum intensity, wash-in and wash-out slopes, time to peak, and relative signal intensity/contrast enhancement can be calculated. Other parameters can be extracted by fitting functions like the gamma-variate function. Region-of-interest data and parametric values can easily be exported.

Results and Conclusion: The system has been successfully tested in animal and patient examinations.
Phase-contrast MR angiography for detection of arteriosclerotic renal artery stenosis
Authors: Duda S. H. , Schick F. , Teufl F. , Müller-Schimpfle M. , Erley C. , Schneider W. , Miller S. , Claussen C. D.
Published: January 2010

Purpose: to compare the accuracy of 3-D phase-contrast (PC) MR imaging with a 2-D time-of-flight (TOF) technique in the detection of arteriosclerotic renal artery stenosis.

Material and Methods: Twenty-two patients with 28 angiographically proven renal artery stenoses were examined in a prospective blinded fashion by using 2-D TOF MR angiography (MRA) with venous saturation (FLASH) and 3-D PC MRA. the renal arteries were subdivided into 3 segments and graded for the presence of stenoses on a scale of 0–4 by 3 radiologists in blind.

Results: the accuracy of TOF and PC imaging in detecting renal artery stenoses was 65% and 77% respectively. Both 2-D TOF and 3-D PC MRA depicted 84% of the stenoses of the proximal renal artery greater than 50% in diameter. Renal artery stenoses greater than 50% and more than 15 mm in distance from the aorta were detected in 40% of cases with the 2-D TOF sequence and in 76% with the 3-D PC technique (p<0.05). the rate of false-negative results was 32%.

Conclusion: PC MRA is better at visualizing stenoses in the middle segment of the renal arteries and supplements conventional TOF techniques with additional information. However, even when the two techniques are combined, the false-negative rate in the MR imaging of stenoses of the renal arteries still needs to be reduced.