bluuebunny/crossref_metadata_2025 huggingface dataset:
Arabic Medicine: Continuation of Greek Tradition and Innovation
Authors: Strohmaier Gotthard
Published: September 2012

An ‘International Institute of Islamic Thought and Civilization’ in Kuala Lumpur, Malaysia, has earned the merit of editing an interesting tract by Abū Bakr Muḥammad ibn Zakarīyā’ al-Rāzī, in Latin tradition known as Rhazes (854–925 or 935), with the title ‘Doubts on Galen’.1This sounds programmatic, but it is confined to minor details, and the author confesses that he feels very uneasy when criticizing a man whom he reveres as his most benevolent master in the medical art, but he is compelled to comply with the principle ‘magis amica veritas’ as Galen himself has always done in his time. The edition is intended to be the start of a series with the title ‘Islamic Thought’, and the director of the institute, Syed Muhammad Naquib al-Attas,2announces in his foreword its aim ‘to formulate an Islamic philosophy of science’, which he further specifies with the following words: ‘In order to learn from the past and be able to equip ourselves spiritually and intellectually for the future, we must return to the early masters of the religious and intellectual tradition of Islam, which was established upon the sacred foundation of the Holy Qur’an and the Tradition of the Holy Prophet.’ (Ref. 1, p. 3). But here we feel obliged to add that Rhazes was not the right man to inaugurate such a series, as he showed himself in his philosophical writings as an outright apostate who deemed all prophets of the revealed religions to be frauds and had even chosen as his spiritual leader, his imam, none else than Socrates.3
The impact of pricing and patent expiration on demand for pharmaceuticals: an examination of the use of broad-spectrum antimicrobials
Authors: Kaier Klaus
Published: September 2012

The aim of the analysis was to determine whether demand in Germany for specific antimicrobial agents is driven by prices that drop considerably when generic substitutes become available. A time-series approach was therefore carried out to explore price elasticities of demand for two different classes of broad-spectrum antimicrobials (fluoroquinolones and cephalosporins) using data on ambulatory antibiotics prescribed on the German statutory health insurance scheme and data on in-hospital antibiotic use in a German teaching hospital. In short, we attempted to explain demand for different antibiotics based on changes in price and hospital-wide morbidity. The data indicate that patent expiration is followed by substantial decreases in the price of antibiotics. In the outpatient sector, all antibiotics included in the analysis showed significant negative own-price elasticities of demand. However, in the hospital settings, significant own-price elasticities were only determined for some antibiotics, although price decreases were stronger than in the outpatient sector. We conclude that price dependence of demand for antimicrobials is present both in the ambulatory and the hospital setting. However, this is especially surprising in the hospital setting because price differences among the antibiotics observed are particularly small compared with the overall cost of hospitalisation.
On Behaviorism in the Cognitive Revolution: Myth and Reactions
Authors: Watrin João Paulo , Darwich Rosângela
Published: September 2012

For a long time, psychology was a discipline devoted to the study of mind. Behaviorism represented a rupture in that tradition, redefining psychology as the study of behavior. The rupture, however, would not have been everlasting. When the cognitive revolution broke out in the 1950s, the study of mental life was renewed in the form of cognitivism. Since then, it is usually told that the cognitive revolution displaced behaviorism, causing the latter's decline or even its death. Nonetheless, at that same time, behaviorism saw the growth of behavior analysis, which remained until today as a living behaviorist field. This article analyzes how behaviorism is depicted in the story of the cognitive revolution, as well as some of the reactions that portrayal generated within behavior analysis. It is argued that the story of the cognitive revolution affirms the importance of cognitivism and consolidates its historical identity but fosters the movement at the expense of behaviorism's depiction. At the same time, behavior analysts’ reactions often contradict the revolution's story and, consequently, offer an alternative but disarticulated version of history. As a result, each side tells a different story, and the case would be illustrative of how such kind of stories can favor one position while distorting some notions.
Minimal conformational plasticity enables TCR cross-reactivity to different MHC class II heterodimers
Authors: Holland Christopher J. , Rizkallah Pierre J. , Vollers Sabrina , Calvo-Calle J. Mauricio , Madura Florian , Fuller Anna , Sewell Andrew K. , Stern Lawrence J. , Godkin Andrew , Cole David K.
Published: September 2012

Successful immunity requires that a limited pool of αβ T-cell receptors (TCRs) provide cover for a vast number of potential foreign peptide antigens presented by ‘self’ major histocompatibility complex (pMHC) molecules. Structures of unligated and ligated MHC class-I-restricted TCRs with different ligands, supplemented with biophysical analyses, have revealed a number of important mechanisms that govern TCR mediated antigen recognition. HA1.7 TCR binding to the influenza hemagglutinin antigen (HA306–318) presented by HLA-DR1 or HLA-DR4 represents an ideal system for interrogating pMHC-II antigen recognition. Accordingly, we solved the structure of the unligated HA1.7 TCR and compared it to both complex structures. Despite a relatively rigid binding mode, HA1.7 T-cells could tolerate mutations in key contact residues within the peptide epitope. Thermodynamic analysis revealed that limited plasticity and extreme favorable entropy underpinned the ability of the HA1.7 T-cell clone to cross-react with HA306–318 presented by multiple MHC-II alleles.
2-APB-potentiated channels amplify CatSper-induced Ca2+ signals in human sperm
Authors: Lefièvre Linda , Nash Katherine , Mansell Steven , Costello Sarah , Punt Emma , Correia Joao , Morris Jennifer , Kirkman-Brown Jackson , Wilson Stuart M. , Barratt Christopher L. R. , Publicover Stephen
Published: September 2012

Ca2+i signalling is pivotal to sperm function. Progesterone, the best-characterized agonist of human sperm Ca2+i signalling, stimulates a biphasic [Ca2+]i rise, comprising a transient and subsequent sustained phase. In accordance with recent reports that progesterone directly activates CatSper, the [Ca2+]i transient was detectable in the anterior flagellum (where CatSper is expressed) 1–2 s before responses in the head and neck. Pre-treatment with 5 μM 2-APB (2-aminoethoxydiphenyl borate), which enhances activity of store-operated channel proteins (Orai) by facilitating interaction with their activator [STIM (stromal interaction molecule)] ‘amplified’ progesterone-induced [Ca2+]i transients at the sperm neck/midpiece without modifying kinetics. The flagellar [Ca2+]i response was unchanged. 2-APB (5 μM) also enhanced the sustained response in the midpiece, possibly reflecting mitochondrial Ca2+ accumulation downstream of the potentiated [Ca2+]i transient. Pre-treatment with 50–100 μM 2-APB failed to potentiate the transient and suppressed sustained [Ca2+]i elevation. When applied during the [Ca2+]i plateau, 50–100 μM 2-APB caused a transient fall in [Ca2+]i, which then recovered despite the continued presence of 2-APB. Loperamide (a chemically different store-operated channel agonist) enhanced the progesterone-induced [Ca2+]i signal and potentiated progesterone-induced hyperactivated motility. Neither 2-APB nor loperamide raised pHi (which would activate CatSper) and both compounds inhibited CatSper currents. STIM and Orai were detected and localized primarily to the neck/midpiece and acrosome where Ca2+ stores are present and the effects of 2-APB are focussed, but store-operated currents could not be detected in human sperm. We propose that 2-APB-sensitive channels amplify [Ca2+]i elevation induced by progesterone (and other CatSper agonists), amplifying, propagating and providing spatio-temporal complexity in [Ca2+]i signals of human sperm.
Defining the boundaries of species specificity for the Saccharomyces cerevisiae glycosylphosphatidylinositol transamidase using a quantitative in vivo assay
Authors: Morissette Rachel , Varma Yug , Hendrickson Tamara L.
Published: September 2012

In eukaryotes, GPI (glycosylphosphatidylinositol) lipid anchoring of proteins is an abundant post-translational modification. The attachment of the GPI anchor is mediated by GPI-T (GPI transamidase), a multimeric, membrane-bound enzyme located in the ER (endoplasmic reticulum). Upon modification, GPI-anchored proteins enter the secretory pathway and ultimately become tethered to the cell surface by association with the plasma membrane and, in yeast, by covalent attachment to the outer glucan layer. This work demonstrates a novel in vivo assay for GPI-T. Saccharomyces cerevisiae INV (invertase), a soluble secreted protein, was converted into a substrate for GPI-T by appending the C-terminal 21 amino acid GPI-T signal sequence from the S. cerevisiae Yapsin 2 [Mkc7p (Y21)] on to the C-terminus of INV. Using a colorimetric assay and biochemical partitioning, extracellular presentation of GPI-anchored INV was shown. Two human GPI-T signal sequences were also tested and each showed diminished extracellular INV activity, consistent with lower levels of GPI anchoring and species specificity. Human/fungal chimaeric signal sequences identified a small region of five amino acids that was predominantly responsible for this species specificity.
Introgression of Brown Norway CYP4A genes on to the Dahl salt-sensitive background restores vascular function in SS-5BN consomic rats
Authors: Lukaszewicz Kathleen M. , Falck John R. , Manthati Vijaya L. , Lombard Julian H.
Published: September 2012

The present study tested the hypothesis that the Dahl SS (salt-sensitive) rat has vascular dysfunction due, in part, to the up-regulation of the CYP4A/20-HETE (cytochrome P450 ω-hydroxylase 4A)/20-hydroxyeicosatetraenoic acid) system. To assess the role of vascular 20-HETE, SS rats were compared with SS-5BN consomic rats, carrying CYP4A alleles on chromosome 5 from the normotensive BN (Brown Norway) introgressed on to the SS genetic background. Cerebral arteries from SS-5BN rats had less CYP4A protein than arteries from SS rats fed either NS (normal-salt, 0.4% NaCl) or HS (high-salt, 4.0% NaCl) diet. ACh (acetylcholine)-induced dilation of MCAs (middle cerebral arteries) from SS and SS-5BN rats was present in SS-5BN rats fed on either an NS or HS diet, but absent in SS rats. In SS rats fed on either diet, ACh-induced dilation was restored by acute treatment with the CYP4A inhibitor DDMS (N-methyl-sulfonyl-12,12-dibromododec-11-enamide) or the 20-HETE antagonist 20-HEDE [20-hydroxyeicosa-6(Z),15(Z)-dienoic acid]. The restored response to ACh in DDMS-treated SS rats was inhibited by L-NAME (NGnitro-L-arginine methyl ester) and unaffected by indomethacin or MS-PPOH [N-methylsulfonyl-6-(2-propargyloxyphenyl)hexanamide]. Vascular relaxation responses to the NO donor C5FeN6Na2O were intact in both SS and SS-5BN rats and unaffected by the acute addition of DDMS, indicating that the vascular dysfunction of the SS rat is due to a reduced bioavailability of NO instead of failure of the VSMCs (vascular smooth muscle cells) to respond to the vasodilator. Superoxide levels in cerebral arteries of SS-5BN rats [evaluated semi-quantitatively by DHE (dihydroethidium) fluorescence] were lower than those in the arteries of SS rats. These findings indicate that SS rats have an up-regulation of the CYP4A/20-HETE pathway resulting in elevated ROS (reactive oxygen species) and reduced NO bioavailability causing vascular dysfunction.
Extraction d’une incisive mandibulaire en orthodontie :
indication, plan de traitement et gestion clinique pour différentes malocclusions
Authors: Chaqués Asensi José
Published: September 2012

Extraire une incisive mandibulaire est une approche thérapeutique qui fait débat, depuis
quelques dizaines d’années, dans le monde de l’orthodontie. Publiés récemment, différents
travaux ont apporté des informations substantielles et structurées qui pourraient nous
aider à réaliser ce type de traitement dans des contextes choisis, en obtenant de bons
résultats, de manière prévisible. Cet article se fixe pour objectif de résumer les
informations disponibles pour structurer le diagnostic et quantifier les paramètres qui
peuvent être mesurés, ceci pour orienter le clinicien dans la prise de décision concernant
l’indication et l’utilisation de cette alternative de traitement. Il s’agit de mettre en
place un cadre clinique clair qui pourrait être utilisé par l’orthodontiste comme une
ligne de référence dans la pratique quotidienne. Quatre cas illustrent l’indication de ce
type de plan de traitement dans différentes situations cliniques.
Les cellules souches de la pulpe dentaire : caractéristiques,
cryopréservation et potentialités thérapeutiques
Authors: Collart Dutilleul Pierre-Yves , Thonat Catherine , Jacquemart Pierre , Cuisinier Frédéric , Levallois Bernard , Chaubron Franck
Published: September 2012

La découverte des cellules souches et de leurs potentialités a fait émerger de nouvelles
formes de thérapies avec le développement de méthodes de bio-ingénierie cellulaire et
tissulaire qui sous-tendent la médecine de demain. La disponibilité de cellules souches et
leur conservation deviennent de ce fait un enjeu pour la santé de chacun. Parmi les
différentes sources de cellules souches, celles de la pulpe dentaire présentent les
avantages d’être pluripotentes, de pouvoir être cryopréservées et conservées durant de
longues périodes sans perdre leur capacité de multiplication et de différenciation et
enfin elles sont facilement accessibles. Les dents de sagesse ou les dents de lait
extraites pour des raisons médicales sont une opportunité pour chacun de conserver des
cellules souches pour un usage autologue. Des biobanques autorisées et spécialisées dans
la préparation et la conservation des cellules souches pulpaires ouvrent l’accès à la
médecine régénérative autologue de l’avenir.
Reconstitutions totales des articulations temporo-mandibulaires
par des implants alloplastiques combinées à un traitement d’orthodontie dans un cas de
résorption condylienne idiopathique
Authors: Chung Chooryung J. , Choi Yoon-Jeong , Kim In-Sil , Huh Jong-Ki , Kim Hyung-Gon , Kim Kyung-Ho
Published: September 2012

Ce rapport de cas montre le traitement réussi d’un adulte présentant une classe II
squelettique avec une béance secondaire à la résorption idiopathique des condyles
mandibulaires. La reconstruction totale des articulations temporo-mandibulaires par des
implants alloplastiques et la rotation dans le sens anti-horaire du complexe
maxillo-mandibulaire, associées à un traitement d’orthodontie, ont permis d’obtenir un
résultat satisfaisant avec une amélioration esthétique et fonctionnelle maximale.
Complex network classification using partially self-avoiding deterministic walks
Authors: Gonçalves Wesley Nunes , Martinez Alexandre Souto , Bruno Odemir Martinez
Published: September 2012

Complex networks have attracted increasing interest from various fields of science. It has been demonstrated that each complex network model presents specific topological structures which characterize its connectivity and dynamics. Complex network classification relies on the use of representative measurements that describe topological structures. Although there are a large number of measurements, most of them are correlated. To overcome this limitation, this paper presents a new measurement for complex network classification based on partially self-avoiding walks. We validate the measurement on a data set composed by 40000 complex networks of four well-known models. Our results indicate that the proposed measurement improves correct classification of networks compared to the traditional ones.
High-resolution spectroscopy used to measure inertial confinement fusion neutron spectra on Omega (invited)
Authors: Forrest C. J. , Radha P. B. , Glebov V. Yu. , Goncharov V. N. , Knauer J. P. , Pruyne A. , Romanofsky M. , Sangster T. C. , Shoup M. J. , Stoeckl C. , Casey D. T. , Gatu-Johnson M. , Gardner S.
Published: September 2012

The areal density (ρR) of cryogenic DT implosions on Omega is inferred by measuring the spectrum of neutrons that elastically scatter off the dense deuterium (D) and tritium (T) fuel. Neutron time-of-flight (nTOF) techniques are used to measure the energy spectrum with high resolution. High signal-to-background data has been recorded on cryogenic DT implosions using a well-collimated 13.4-m line of sight and an nTOF detector with an advanced liquid scintillator compound. An innovative method to analyze the elastically scattered neutron spectra was developed using well-known cross sections of the DT nuclear reactions. The estimated areal densities are consistent with alternative ρR measurements and 1-D simulations.
Piezoresponse force microscopy studies on the domain structures and local switching behavior of Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals
Authors: Li Qian , Liu Yun , Withers Ray L. , Wan Yuhui , Li Zhenrong , Xu Zhuo
Published: September 2012

The static domain structures and local switching behavior of relaxor ferroelectric 0.29Pb(In1/2Nb1/2)O3-0.44Pb(Mg1/3Nb2/3)O3-0.27PbTiO3 single crystals at three crystal orientations are studied using piezoresponse force microscopy (PFM). PFM domain imaging shows that both the [001] and [111] oriented crystals exhibit a labyrinth-like surface domain pattern while at the [110] crystal orientation the domains are preferentially aligned along 〈110〉 directions. Vertical and lateral PFM images are used in combination to discuss the polarization vector alignment underlying the observed domain behaviour. Piezoresponse hysteresis loops acquired from these crystals indicate that the [111] crystal orientation has distinct local switching characteristics from the other two orientations in terms of, e.g., coercive voltage. Moreover, we investigate the tip-induced domain growth kinetics on an externally poled [001] crystal, the results of which exemplify an important role of extrinsic factors, e.g., the charge injection effect, in the domain patterning process.
Piezoresponse force microscopy characterization of high aspect ratio ferroelectric nanostructures
Authors: Bernal Ashley , Bassiri-Gharb Nazanin
Published: September 2012

Band-excitation piezoresponse force microscopy is used to characterize the piezoelectric and ferroelectric response of high aspect ratio PbZr0.52Ti0.48O3 (PZT) nanostructures. It is found that the resonance contact frequency of the system (cantilever and sample) changed by more than 60 kHz across the sample due to variations in mechanical contact with the piezoelectrically active and inactive materials, as well as the large height variations. Probed locations on the PZT nanotubes showed enhanced intrinsic piezoelectric response and saturated piezoresponse hysteresis loops compared to off-tube locations.
Domain growth kinetics in La0.89Sr0.11MnO3 single crystal studied by piezoresponse force microscopy
Authors: Panwar Neeraj , Bdikin Igor K. , Morozovska Anna N. , Kholkin Andrei L.
Published: September 2012

Ferroelectric-like nanodomains have been written by applying voltage pulse of different durations to the surface of La0.89Sr0.11MnO3 manganite single crystals and subsequently examined by the piezoresponse force microscope (PFM) technique. The domain wall velocity was then calculated based on conventional PFM procedure. A transition from the non-activated to the activated type domain wall motion has been observed due to the inhomogeneous spatial variation of the tip-induced electric field. The maximum domain size that can develop in a non-activated motion process has been found to be ∼170 nm. The formation of these ferroelectric-like nano domains at room temperature by PFM has been rationalized within phenomenological model based on Landau-Ginzburg formalism. Written domains are sufficiently stable and are attractive for device applications in nonvolatile random-access memories and development of metamaterials.
Structural, dielectric, ferroelectric and piezoresponse force microscopy characterizations of bilayered Bi0.9Dy0.1FeO3/K0.5Na0.5NbO3 lead-free multiferroic films
Authors: Chen Ling , Ren Wei , Ye Zuo-Guang , Tian Aifen , Wu Xiaoqing , Shi Peng
Published: September 2012

The structure, dielectric and ferroelectric properties of the bilayered Bi0.9Dy0.1FeO3/K0.5Na0.5NbO3 (BDF/KNN) lead-free thin films deposited on the Pt/TiO2/SiO2/Si substrates by pulsed laser deposition with different thickness ratios have been characterized. It is found that the introduction of the bottom KNN layer can effectively reduce the leakage current of the composite film, allowing the high polarization of the BDF layer to be displayed. The bilayered film with KNN to BDF thickness ratio of 1.2 exhibits the best dielectric and ferroelectric properties, with a remanent polarization 2Pr = 16.3 μC/cm2. The polar domain structure of that film has been imaged by means of piezoresponse force microscopy (PFM) and the switching of the polarization has been realized under an applied electric field of ±12 V, confirming the ferroelectricity in the BDF/KNN composite film.
Electronically induced surface reactions: Evolution, concepts, and perspectives
Authors: Menzel Dietrich
Published: September 2012

This is a personal account of the development of the title subject which is the broader field encompassing surface photochemistry. It describes the early times when the main interest centered on desorption induced by slow electrons, follows its evolution in experiment (use of synchrotron radiation and connections to electron spectroscopies; use of lasers) and mechanisms, and briefly mentions the many different subfields that have evolved. It discusses some practically important aspects and applications and ends with an account of an evolving new subfield, the application to photochemistry on nanoparticles.
Surface aligned reaction
Authors: Ning Zhanyu , Polanyi John C.
Published: September 2012

This paper reflects on three decades during which the study of surface aligned reaction (SAR) has advanced. The objective in SAR, which in considerable part still lies ahead, is the simultaneous control of atomic and molecular “collision energies, collision angles, and impact parameter.” Following a discussion of the benefits of such an approach we review the progress made, and, as a stimulus to experiment, present new calculations of SAR dynamics for bimolecular reaction at a metal surface. It seems reasonable to suppose that we are now entering a decade in which a combination of scanning tunneling microscopy and femtosecond laser spectroscopy will bring the full realisation of SAR.
Computational studies of ionic liquids: Size does matter and time too
Authors: Gabl Sonja , Schröder Christian , Steinhauser Othmar
Published: September 2012

Taking the molecular ionic liquid 1-ethyl-3-methylimidazolium triflate as a reference system, the size and time dependence of molecular dynamics simulation studies is analyzed in a systematic way. Based on an all atom force field, trajectories of 70 ns length, covering samples of 8–2000 ion pairs, were generated and analyzed in terms of structure as well as single particle and collective dynamics. Although 50 ion pairs seemed sufficient for structure, at least 500 ion pairs were needed for the correct handling of dynamics. For larger systems a linear regime is found, i.e., the respective dynamical properties are a linear function of the inverse box length. In case of translational diffusion coefficients, this linear relation can be rationalised in hydrodynamic terms. The respective formula is essentially determined by viscosity and the inverse box length. Concerning the time dependence, consistent dynamical properties required a time period of 20–30 ns. Nevertheless, size dependence dominates time dependence and has to be primarily addressed.
Chaotic dynamics in cardiac aggregates induced by potassium channel block
Authors: Quail Thomas , McVicar Nevin , Aguilar Martin , Kim Min-Young , Hodge Alex , Glass Leon , Shrier Alvin
Published: September 2012

Chaotic rhythms in deterministic models can arise as a consequence of changes in model parameters. We carried out experimental studies in which we induced a variety of complex rhythms in aggregates of embryonic chick cardiac cells using E-4031 (1.0–2.5 μM), a drug that blocks the hERG potassium channel. Following the addition of the drug, the regular rhythm evolved to display a spectrum of complex dynamics: irregular rhythms, bursting oscillations, doublets, and accelerated rhythms. The interbeat intervals of the irregular rhythms can be described by one-dimensional return maps consistent with chaotic dynamics. A Hodgkin-Huxley-style cardiac ionic model captured the different types of complex dynamics following blockage of the hERG mediated potassium current.
Sound wave resonances in micro-electro-mechanical systems devices vibrating at high frequencies according to the kinetic theory of gases
Authors: Desvillettes Laurent , Lorenzani Silvia
Published: September 2012

The mechanism leading to gas damping in micro-electro-mechanical systems (MEMS) devices vibrating at high frequencies is investigated by using the linearized Boltzmann equation based on simplified kinetic models and diffuse reflection boundary conditions. Above a certain frequency of oscillation, the sound waves propagating through the gas are trapped in the gaps between the moving elements and the fixed boundaries of the microdevice. In particular, we found a scaling law, valid for all Knudsen numbers Kn (defined as the ratio between the gas mean free path and a characteristic length of the gas flow), that predicts a resonant response of the system. This response enables a minimization of the damping force exerted by the gas on the oscillating wall of the microdevice.
Observation of a 0.5 conductance plateau in asymmetrically biased GaAs quantum point contact
Authors: Bhandari N. , Das P. P. , Cahay M. , Newrock R. S. , Herbert S. T.
Published: September 2012

We report the observation of a robust anomalous conductance plateau near G = 0.5 G0 (G0 = 2e2/h) in asymmetrically biased AlGaAs/GaAs quantum point contacts (QPCs), with in-plane side gates in the presence of lateral spin-orbit coupling. This is interpreted as evidence of spin polarization in the narrow portion of the QPC. The appearance and evolution of the conductance anomaly has been studied at T = 4.2 K as a function of the potential asymmetry between the side gates. Because GaAs is a material with established processing techniques, high mobility, and a relatively high spin coherence length, the observation of spontaneous spin polarization in a side-gated GaAs QPC could eventually lead to the realization of an all-electric spin-valve at tens of degrees Kelvin.
Impact of resonator geometry and its coupling with ground plane on ultrathin metamaterial perfect absorbers
Authors: Huang Li , Chowdhury Dibakar Roy , Ramani Suchitra , Reiten Matthew T. , Luo Sheng-Nian , Azad Abul K. , Taylor Antoinette J. , Chen Hou-Tong
Published: September 2012

We investigate the impact of resonator geometry and its coupling with ground plane on the performance of metamaterial perfect absorbers. Using a cross-resonator as an example structure, we find that the absorber thickness can be further reduced through modifying the geometric dimensions of the resonators. Numerical simulations and theoretical calculations reveal that destructive interference of multiple reflections is responsible for the near-unity absorption. The near-field coupling between the resonator array and ground plane can be significant. When this coupling is taken into account, the theoretical results calculated using the interference model are in excellent agreement with experiments and numerical simulations.
Buried heterostructure vertical-cavity surface-emitting laser with semiconductor mirrors
Authors: Zhao G. , Zhang Y. , Deppe D. G. , Konthasinghe K. , Muller A.
Published: September 2012

We report a buried heterostructure vertical-cavity surface-emitting laser fabricated by epitaxial regrowth over an InGaAs quantum well gain medium. The regrowth technique enables microscale lateral confinement that preserves a high cavity quality factor (loaded Q≈4000) and eliminates parasitic charging effects found in existing approaches. Under optimal spectral overlap between gain medium and cavity mode (achieved here at T = 40 K), lasing was obtained with an incident optical power as low as Pth=10 mW (λp=808 nm). The laser linewidth was found to be ≈3 GHz at Pp≈5 Pth.
Phase-controlled superconducting heat-flux quantum modulator
Authors: Giazotto F. , Martínez-Pérez M. J.
Published: September 2012

We theoretically put forward the concept of a phase-controlled superconducting heat-flux quantum modulator. Its operation relies on phase-dependent heat current predicted to occur in temperature-biased Josephson tunnel junctions. The device behavior is investigated as a function of temperature bias across the junctions, bath temperature, and junctions asymmetry as well. In a realistic Al-based setup the structure could provide temperature modulation amplitudes up to ∼50 mK with flux-to-temperature transfer coefficients exceeding ∼125 mK/Φ0 below 1 K, and temperature modulation frequency of the order of a few MHz. The proposed structure appears as a promising building-block for the implementation of caloritronic devices operating at cryogenic temperatures.
Invited Article: Relation between electric and magnetic field structures and their proton-beam images
Authors: Kugland N. L. , Ryutov D. D. , Plechaty C. , Ross J. S. , Park H.-S.
Published: September 2012

Proton imaging is commonly used to reveal the electric and magnetic fields that are found in high energy density plasmas. Presented here is an analysis of this technique that is directed towards developing additional insight into the underlying physics. This approach considers: formation of images in the limits of weak and strong intensity variations; caustic formation and structure; image inversion to obtain line-integrated field characteristics; direct relations between images and electric or magnetic field structures in a plasma; imaging of sharp features such as Debye sheaths and shocks. Limitations on spatial and temporal resolution are assessed, and similarities with optical shadowgraphy are noted. Synthetic proton images are presented to illustrate the analysis. These results will be useful for quantitatively analyzing experimental proton imaging data and verifying numerical codes.
Analyzing nanotextured transparent conductive oxides for efficient light trapping in silicon thin film solar cells
Authors: Dewan Rahul , Owen Jorj I. , Madzharov Darin , Jovanov Vladislav , Hüpkes Jürgen , Knipp Dietmar
Published: September 2012

Nanotextured contact layers are used in silicon thin film solar cells for increasing the short circuit current and conversion efficiency. We developed an approach to analyze random nanotextured surfaces by atomic force microscopy and image segmentation. It was used to investigate sputtered and wet chemically etched aluminum doped zinc oxide films with various morphologies. The information extracted from the surfaces was correlated with optical simulations of periodically textured thin film solar cells. The results from the surface analysis and optical simulations were also compared with the experimental results obtained for amorphous silicon solar cells prepared on the nanotextured substrates.
1550 nm ErAs:In(Al)GaAs large area photoconductive emitters
Authors: Preu S. , Mittendorff M. , Lu H. , Weber H. B. , Winnerl S. , Gossard A. C.
Published: September 2012

We report on high power terahertz (THz) emission from ErAs-enhanced In0.52Al0.48As-In0.53Ga0.47As superlattices for operation at 1550 nm. ErAs clusters act as efficient recombination centers. The optical power is distributed among a large, microstructured area in order to reduce the local optical intensity. A THz field strength of 0.7 V/cm (1 V/cm peak-to-peak) at 100 mW average optical power has been obtained, with emission up to about 4 THz in air, limited by the detection crystal used in the system.
Degradation and phase noise of InAlN/AlN/GaN heterojunction field effect transistors: Implications for hot electron/phonon effects
Authors: Zhu C. Y. , Wu M. , Kayis C. , Zhang F. , Li X. , Ferreyra R. A. , Matulionis A. , Avrutin V. , Özgür Ü. , Morkoç H.
Published: September 2012

In15.7%Al84.3%N/AlN/GaN heterojunction field effect transistors have been electrically stressed under four different bias conditions: on-state-low-field stress, reverse-gate-bias stress, off-state-high-field stress, and on-state-high-field stress, in an effort to elaborate on hot electron/phonon and thermal effects. DC current and phase noise have been measured before and after the stress. The possible locations of the failures as well as their influence on the electrical properties have been identified. The reverse-gate-bias stress causes trap generation around the gate area near the surface which has indirect influence on the channel. The off-state-high-field stress and the on-state-high-field stress induce deterioration of the channel, reduce drain current and increase phase noise. The channel degradation is ascribed to the hot-electron and hot-phonon effects.
Identification of cortical germ cells in adult ovaries from three phyllostomid bats: Artibeus jamaicensis, Glossophaga soricina and Sturnira lilium
Authors: Antonio-Rubio Nivia Rocio , Porras-Gómez Tania Janeth , Moreno-Mendoza Norma
Published: September 2012

It is generally considered that, in mammals, the ovary is endowed with a finite number of oocytes at the time of birth. However, studies concerning rodents, lemurs and humans suggest the existence of stem cells from the germline that may be involved in germ-cell renewal, maintaining postnatal follicle development. This type of work on wild species is scarce; therefore the objective of this study was to determine ovarian morphology and the presence of progenitor cells from the germline of three species of phyllostomid bats (Artibeus jamaicensis, Glossophaga soricina and Sturnira lilium). The morphological characteristics of the ovaries and the expression of specific markers of germline cells, stem cells and proliferation cells were analysed. The morphology of the ovaries of the three bat species was similar. A polarised ovary with follicles at different stages of development and groups of cortical cells similar to primordial germ cells were observed. Immunofluorescent analysis showed that these cortical cells express germline, stem-cell and proliferative markers, indicating the identification of germ cells that could maintain pluripotency, as well as being mitotically active. This suggests that in the adult ovary of phyllostomid bats there may be a mechanism for the self-renewal of the germline.
The role of hypoxia-induced genes in ovarian angiogenesis
Authors: Meidan Rina , Klipper Eyal , Zalman Yulia , Yalu Ronit
Published: September 2012

The hypoxic microenvironment that occurs in fast-growing tissue such as the corpus luteum (CL) is a major contributor to its ability to survive via the induction of an intricate vascular network. Cellular responses to hypoxia are mediated by hypoxia-inducible factor-1 (HIF-1), an oxygen-regulated transcriptional activator. HIF-1, a heterodimer consisting of a constitutively-expressed β subunit and an oxygen-regulated α subunit, binds to the hypoxia responsive element (HRE) present in the promoter regions of responsive genes. This review summarises evidence for the involvement of hypoxia and HIF-1α in CL development and function. Special emphasis is given to hypoxia-induced, luteal cell-specific expression of multiple genes (vascular endothelial growth factor A (VEGFA), fibroblast growth factor 2 (FGF-2), prokineticin receptor 2 (PK-R2), stanniocalcin 1 (STC-1) and endothelin 2 (EDN-2) that participate in the angiogenic process during CL formation.
Exposure to bisphenol A results in a decline in mouse spermatogenesis
Authors: Zhang Guo-Liang , Zhang Xi-Feng , Feng Yan-Min , Li Lan , Huynh Evanna , Sun Xiao-Feng , Sun Zhong-Yi , Shen Wei
Published: September 2012

Bisphenol A (BPA), a chemical used in many consumer products, interferes with the endocrine system of mammals, including humans. The aim of the present study was to investigate the effect of BPA on spermatogenesis and semen quality. The objective of this study was to assess the effects of BPA on mouse spermatogenesis. CD1 mice were used in all experiments. Mice were treated with different doses of BPA (0, 20 and 40 μg kg–1 day–1from postnatal Day (PND) 3 to PND21, PND 35 or PND49. After 5 weeks BPA treatment, oestrogen receptor α expression was increased in mouse testis, whereas the meiotic progression of germ cells was slowed. Thus, both the quality and quantity of spermatozoa were decreased in 7-week-old mice. However, BPA had no effect on DNA methylation of imprinted genes such as Igf2, Igf2r, Peg3 and H19, in germ cells. In addition, exposure of male mice to BPA resulted in abnormal offspring that were smaller with a low-quality pelage when they were 35 days old. In conclusion, BPA hampers spermatogenesis and the subsequent development of offspring.
Therapeutic outcomes in the Welsh Government's school‐based counselling strategy: An evaluation
Authors: Cooper Mick , Pybis Joanne , Hill Andy , Jones Sylvia , Cromarty Karen
Published: September 2012

Aims: The purpose of this study was to evaluate the outcomes of school‐based counselling, as delivered in the Welsh Government's School‐based Counselling Strategy, for reducing psychological distress in young people aged 11–18. Method: The study used a quantitative cohort design, comparing levels of distress on either the Young Person's CORE (YP‐CORE) or the Strengths and Difficulties Questionnaire (SDQ) from baseline to endpoint. Data were available on 3613 episodes of counselling, across 42 datasets. Meta‐analytical procedures were used to identify the mean effect size and predictors of outcomes. Results: Within each dataset, counselling was associated with significant reductions in psychological distress, with a mean effect size (d) of 0.93(95% CI = 0.89–0.97) using a fixed effects model and 1.09 (95% CI = 0.97–1.22) using a random effects model. Datasets using the YP‐CORE had larger effect sizes than those using the SDQ, and datasets with more complete response rates had lower outcomes than those with poorer response rates. Conclusion: The results confirm that school‐based counselling, as delivered in the UK, is associated with significant reductions in psychological distress, comparable to adult counselling and psychotherapy services.
New Programmable Electrofishing Device for Use in Aquaculture
Authors: Soto Fulgencio , Jiménez Manuel , Mateo Antonio , Villarejo José A , Jódar Esther , Jiménez Jacinto
Published: September 2012

The new equipment described here was developed in response to a shortcoming in the technology available for electrofishing marine species. The system supplies a need that exists in commercial operations, and also allows research into the effect of the waveform on the quality of the meat. The equipment is capable of generating any kind of waveform, identifying the environment the electrodes are in, and logging the voltage and current values that are applied to kill the fish. Although it has been designed in the context of electrofishing for tuna, it is perfectly compatible with electrofishing in freshwater. The system is composed of two interacting parts: a software section and a hardware section. The software is capable of determining the relationship of each of the electrical wave parameters with the final quality of the meat. The electrical hardware main constituent is a full bridge with an inductor-capacitor (LC) filter. The effectiveness of two different types of control for this kind of converter is compared: one being a “feedback” control, and the other a “feedforward” control. This equipment has been tested under natural conditions using three different waveforms, selected on the basis of our previous tuna electrostunning experience. These are: high-frequency pulsed DC, low-frequency pulsed DC, and low-frequency, decreasing exponential AC. Of the tested waveforms, low-frequency, decreasing exponential AC showed the best results as far as flesh quality was concerned. The system showed, in all cases, a high degree of reliability and safety.
On the asymptotics of Γ_{𝑞}(𝑧) as 𝑞 approaches 1
Authors: Zhang Ruiming
Published: September 2012

In this note we give a derivation of the asymptotic main term for the

q
q

-Gamma function

Γ

q

(
z
)

\Gamma _{q}\left (z\right )

as

q
q

approaches

1
1

. Our formula is valid for all fixed

z
∈

C

z\in \mathbb {C}

except non-positive integers.
JEnsembl: a version-aware Java API to Ensembl data systems
Authors: Paterson Trevor , Law Andy
Published: September 2012

Motivation: The Ensembl Project provides release-specific Perl APIs for efficient high-level programmatic access to data stored in various Ensembl database schema. Although Perl scripts are perfectly suited for processing large volumes of text-based data, Perl is not ideal for developing large-scale software applications nor embedding in graphical interfaces. The provision of a novel Java API would facilitate type-safe, modular, object-orientated development of new Bioinformatics tools with which to access, analyse and visualize Ensembl data.

Results: The JEnsembl API implementation provides basic data retrieval and manipulation functionality from the Core, Compara and Variation databases for all species in Ensembl and EnsemblGenomes and is a platform for the development of a richer API to Ensembl datasources. The JEnsembl architecture uses a text-based configuration module to provide evolving, versioned mappings from database schema to code objects. A single installation of the JEnsembl API can therefore simultaneously and transparently connect to current and previous database instances (such as those in the public archive) thus facilitating better analysis repeatability and allowing ‘through time’ comparative analyses to be performed.

Availability: Project development, released code libraries, Maven repository and documentation are hosted at SourceForge (http://jensembl.sourceforge.net).

Contact:  jensembl-develop@lists.sf.net, andy.law@roslin.ed.ac.uk, trevor.paterson@roslin.ed.ac.uk
Selling Paris: The Real Estate Market and Commercial Culture in the Fin-de-siècle Capital
Authors: Yates Alexia
Published: September 2012

“Selling Paris” explores the cultural, economic, and spatial parameters of private construction in the French capital at the turn of the twentieth century. In contrast to the state-centered accounts that currently characterize our understanding of Paris as a capital of modernity, this project looks to private property owners, real estate brokers, and speculative developers, as well as the moral economy in which their projects took place, in order to understand the elaboration of the built landscape of the modern metropolis. I argue that new classes of market intermediaries—namely estate agents, market-oriented architects, and small-scale joint-stock firms—emerged in this period to build and market residential spaces, establishing apartments and buildings as merchandise and tenants as clients. Focusing on the activities of these commercial actors reveals the existence of a French culture of commerce centered on speculation and risk-taking, a business culture that profoundly affected the production of residential space during of one of the city's greatest periods of expansion. Thus, in contradistinction to scholarly accounts of both French entrepreneurialism and Parisian urban development, this project reconstructs the activities of a dynamic capitalist class whose uncoordinated projects were the main authors of the capital city's urban fabric. Tracing the manner in which housing and property operated as a commercial object during a crucial period of urbanization, moving between and among the economic activities of investment, speculation, production, and consumption, this project seeks to present a research agenda for both the cultural history of markets and the economic history of cities.
Clinical Predictors of Influenza in Young Children: The Limitations of “Influenza-Like Illness”
Authors: Conway Nicholas T. , Wake Zoe V. , Richmond Peter C. , Smith David W. , Keil Anthony D. , Williams Simon , Kelly Heath , Carcione Dale , Effler Paul V. , Blyth Christopher C. ,   on Behalf of the Western Australia Influenza Vaccine Effectiveness (WAIVE) Team
Published: September 2012

Background

Influenza-like illness (ILI) definitions have been infrequently studied in young children. Despite this, clinical definitions of ILI play an important role in influenza surveillance. This study aims to identify clinical predictors of influenza infection in children ≤5 years old from which age-specific ILI definitions are then constructed.

Methods

Children aged 6–59 months with a history of fever and acute respiratory symptoms were recruited in the Western Australia Influenza Vaccine Effectiveness (WAIVE) Study. Clinical data and per-nasal specimens were obtained from all children. Logistic regression identified significant predictors of influenza infection. Different ILI definitions were compared for diagnostic accuracy.

Results

Children were recruited from 2 winter influenza seasons (2008–2009; n = 944). Of 919 eligible children, 179 (19.5%) had laboratory-confirmed influenza infection. Predictors of infection included increasing age, lack of influenza vaccination, lower birth weight, fever, cough, and absence of wheeze. An ILI definition comprising fever ≥38°C, cough, and no wheeze had 58% sensitivity (95% confidence interval [CI], 50–66), 60% specificity (95% CI, 56–64), 26% positive predictive value (95% CI, 21–31), and 86% negative predictive value (95% CI, 82–89). The addition of other symptoms or higher fever thresholds to ILI definition had little impact. The Centers for Disease Control and Prevention definition of ILI (presence of fever [≥37.8°C] and cough and/or sore throat) was sensitive (92%; 95% CI, 86–95), yet lacked specificity (10%; 95% CI, 8–13) in this population.

Conclusions

Influenza-like illness is a poor predictor of laboratory-confirmed influenza infection in young children but can be improved using age-specific data. Incorporating age-specific ILI definitions and/or diagnostic testing into influenza surveillance systems will improve the accuracy of epidemiological data.