bluuebunny/crossref_metadata_2025 huggingface dataset:
Egg size manipulation in the migrant skipper, Parnara guttata guttata (Lepidoptera: Hesperiidae), in response to different host plants
Authors: Mizumoto Makoto , Nakasuji Fusao
Published: February 2007

Female adults of the migrant skipper, Parnara guttata guttata, lay different‐sized eggs on different host plants in different generations. Moreover, P. g. guttata maintains large egg size variation either in the population or in the individual. Why such phenotypic plasticity in egg size is maintained has not been clarified. In the present study we performed a series of experiments to verify whether or not females of P. g. guttata discriminate between the different host plants, i.e., rice plant Oriza sativa in the first and second generations and cogon grass Imperata cylindrica in the third (overwintering) generation and manipulate egg size accordingly on these host plants. When a caged female was allowed to lay eggs alternatively on soft‐leafed rice plant and tough‐leafed cogon grass, the size of the eggs laid on cogon grass was significantly larger than that on rice plant. When a caged female was allowed to lay eggs on the two host plants that were supplied on alternate days, the size of eggs laid on cogon grass was also significantly larger than that on rice plant. A preliminary experiment using crude extract from the plants suggested that females did not manipulate egg size in response to chemical stimulants alone. The skipper female was able to lay different‐sized eggs instantaneously after assessing the host plant. However, the reaction norm to different host plants differed among females. Eggs of various sizes were matured in each ovariole, and egg size variation at the lowest part of the ovariole ranged from the size of the larger eggs laid on cogon grass to that of the smaller eggs laid on rice plant, although how the female chose the appropriate‐sized egg at each occasion is unknown.
Influence of consumer mutual interference on the stabilization of a three‐level trophic system
Authors: Zhang Fengpan , Li Zi‐zhen , Zhang Xinfeng , Gao Meng
Published: February 2007

In this paper, we present a three‐level (food–prey–predator) trophic food chain which includes consumer mutual interference (MIF). In contrast with other analyses, we consider the effect of both prey and predator MIF on the dynamics of a three‐level trophic system. MIF is generally considered to exert a stabilizing effect on population dynamics based on the predator–prey model. However, results from analytical and numerical simulations utilizing a simple three‐species food chain model suggest that while the addition of prey MIF to the model provides a stabilizing influence, as the chaotic dynamics collapse to a stable steady state, adding only predator MIF to the model can only stabilize the system at intermediate MIF values. The three‐species trophic food chain is also stabilized when combination of both prey and predator MIF is added to the model. Our work serves to provide insight into the effects of MIF in the real world.
Variation in male mating success in the paternal nest brooder, Rhinogobius goby, along a river course
Authors: Tamada Kazuaki
Published: February 2007

Rhinogobius sp. CB (cross band type) is an amphidromous freshwater goby which receives paternal nest care under stones on river beds. This goby is known to migrate to the upper reaches of rivers as it grows. In the present study, the relationships among male mating success of Rhinogobius sp. CB, male body size, the size frequency distribution of river bed stones and the presence of the sympatric goby Tridentigerbrevispinis (which uses nest sites similar to those of Rhinogobius sp. CB) were investigated along the course of the Aizu River, Wakayama Prefecture, Japan. In the lower reach, where T.brevispinis was present and large stones were scarce, the sizes of the nest stones and the egg clusters of male Rhinogobius sp. CB were smaller than those of T.brevispinis. In the middle and the upper reaches, where T.brevispinis was absent and large stones were abundant, males of Rhinogobius sp. CB used larger nest stones than in the lower reach. In both gobies, there were positive correlations among male body size, nest size and egg cluster size in all reaches. Nest‐choice experiments carried out in the laboratory, with or without a rival, showed that males of both gobies preferentially used large nest sites and that large males had an advantage in male‐male competition for large nest sites. These results indicate that large male body size can increase male mating success and that male mating success increases in the upper reach in this goby. The migration pattern of Rhinogobius sp. CB was also discussed in relation to these findings.
Expression of CYP2S1 in human hepatic stellate cells
Authors: Marek Carylyn J. , Tucker Steven J. , Koruth Matthew , Wallace Karen , Wright Matthew C.
Published: February 2007

Activated stellate cells are myofibroblast‐like cells associated with the generation of fibrotic scaring in chronically damaged liver. Gene chip analysis was performed on cultured fibrotic stellate cells. Of the 51 human CYP genes known, 13 CYP and 5 CYP reduction‐related genes were detected with 4 CYPs (CYP1A1, CYP2E1, CY2S1 and CYP4F3) consistently present in stellate cells isolated from three individuals. Quantitative RT‐PCR indicated that CYP2S1 was a major expressed CYP mRNA transcript. The presence of a CYP2A‐related protein and testosterone metabolism in stellate cell cultures suggest that stellate cells express specific functional isoforms of CYP of which a major form is CYP2S1.
Ether stress‐induced Alzheimer‐like tau phosphorylation in the normal mouse brain
Authors: Ikeda Yoshiko , Ishiguro Koichi , Fujita Shinobu C.
Published: February 2007

Tau is reversibly hyperphosphorylated in the mouse brain by starvation or cold water swimming. Here, we report tau phosphorylation in the hippocampus of normal mouse after ether anesthesia, known to trigger typical stress reactions. Robust phosphorylation of tau was observed immediately and 10 min after ether vapor exposure at Ser202/Thr205 and Thr231/Ser235, sites typically phosphorylated in Alzheimer brains. The phosphorylation levels returned to baseline by 1 h. The most conspicuous and consistent change in the protein kinases studied was the inactivating phosphorylation of Ser9 of TPKI/GSK3β in close correspondence with tau phosphorylation. These findings show that tau phosphorylation is a rapid physiological process integral to stress response system, and suggest involvement therein of TPKI/GSK3β.
Simulation of cavitation bubbles in a convergent–divergent nozzle water jet
Authors: QIN Z. , BREMHORST K. , ALEHOSSEIN H. , MEYER T.
Published: February 2007

A model for simulating the process of growth, collapse and rebound of a cavitation bubble travelling along the flow through a convergent–divergent nozzle producing a cavitating water jet is established. The model is based on the Rayleigh–Plesset bubble dynamics equation using as inputs ambient pressure and velocity profiles calculated with the aid of computational fluid dynamics (CFD) flow modelling. A variable time-step technique is applied to solve the highly nonlinear second-order differential equation. This technique successfully solves the Rayleigh–Plesset equation for wide ranges of pressure variation and bubble original size and saves considerable computing time. Inputs for this model are the pressure and velocity data from CFD calculation. To simulate accurately the process of bubble growth, collapse and rebound, a heat transfer model, which includes the effects of conduction plus radiation, is developed to describe the thermodynamics of the incondensable gas inside the bubble. This heat transfer model matches previously published experimental data well. Assuming that single bubble behaviour also applies to bubble clouds, the calculated distance from the nozzle exit travelled by the bubble to the point where the bubble size becomes invisible is taken to be equal to the bubble cloud length observed. The predictions are compared with experiments carried out in a cavitation cell and show good agreement for different nozzles operating at different pressure conditions.
Marine ice-sheet dynamics. Part 1. The case of rapid sliding
Authors: SCHOOF CHRISTIAN
Published: February 2007

Marine ice sheets are continental ice masses resting on bedrock below sea level. Their dynamics are similar to those of land-based ice sheets except that they must couple with the surrounding floating ice shelves at the grounding line, where the ice reaches a critical flotation thickness. In order to predict the evolution of the grounding line as a free boundary, two boundary conditions are required for the diffusion equation describing the evolution of the grounded-ice thickness. By analogy with Stefan problems, one of these conditions imposes a prescribed ice thickness at the grounding line and arises from the fact that the ice becomes afloat. The other condition must be determined by coupling the ice sheet to the surrounding ice shelves. Here we employ matched asymptotic expansions to study the transition from ice-sheet to ice-shelf flow for the case of rapidly sliding ice sheets. Our principal results are that the ice flux at the grounding line in a two-dimensional ice sheet is an increasing function of the depth of the sea floor there, and that ice thicknesses at the grounding line must be small compared with ice thicknesses inland. These results indicate that marine ice sheets have a discrete set of steady surface profiles (if they have any at all) and that the stability of these steady profiles depends on the slope of the sea floor at the grounding line.
Hydrodynamic interaction between two identical capsules in simple shear flow
Authors: LAC ETIENNE , MOREL ARNAUD , BARTHÈS-BIESEL DOMINIQUE
Published: February 2007

We present a numerical model of the hydrodynamic interactions between two capsules freely suspended in a simple shear flow. The capsules are identical and each consists of a liquid droplet enclosed by a thin hyperelastic membrane, devoid of bending resistance and obeying a neo-Hookean constitutive law. The two capsules are slightly prestressed with a given inflation ratio in order to avoid the small deformation instability due to compression observed for a single capsule in simple shear flow. The viscosity ratio between the interior and exterior fluids of the capsule is taken to be unity and creeping flow conditions are assumed to prevail. The boundary-element method is used with bi-cubic B-splines as basis functions on a structured mesh in order to discretize the capsule surface. A new method using two grids with initially orthogonal pole axes is developed to eliminate polar singularities in the load calculation and to allow for long computation times. Two capsules suspended in simple shear flow usually have different velocities and thus eventually pass each other. We study this crossing process as a function of flow strength and initial particle separation. We find that hydrodynamic interactions during crossing lead to large shape alterations, elevated elastic tensions in the membrane and result in an irreversible trajectory shift of the capsules. Furthermore, a tendency towards buckling is observed, particularly during the separation phase where large pressure differences occur. Our results are in qualitative agreement with those obtained for a pair of interacting liquid droplets but show the specific role played by the membrane of capsules.
Instability modes and transition of pulsatile stenotic flow: pulse-period dependence
Authors: BLACKBURN H. M. , SHERWIN S. J.
Published: February 2007

The instability modes arising within simple non-reversing pulsatile flows in a circular tube with a smooth axisymmetric constriction are examined using global Floquet stability analysis and direct numerical simulation. The sectionally averaged pulsatile flow is represented with one harmonic component superimposed on a time-mean flow. We have previously identified a period-doubling global instability mechanism associated with alternating tilting of the vortex rings that are ejected out of the stenosis throat with each pulse. Here we show that while alternating tilting of vortex rings is the primary instability mode for comparatively larger reduced velocities associated with long pulse periods (or low Womersley numbers), for lower reduced velocities that are associated with shorter pulse periods the primary instability typically manifests as azimuthal waves (Widnall instability modes) of low wavenumber that grow on each vortex ring. Convective shear-layer instabilities are also supported by the types of flow considered. To provide an insight into the comparative role of these types of instability, which have still shorter temporal periods, we also introduce high-frequency low-amplitude perturbations to the base flows of the above global instabilities. For the range of parameters considered, we observe that the dominant features of the primary Floquet instability persist, but that the additional presence of the convective instability can have a destabilizing effect, especially for long pulse periods.
Proper orthogonal decomposition and low-dimensional modelling of thermally driven two-dimensional flow in a horizontal rotating cylinder
Authors: HASAN NADEEM , SANGHI SANJEEV
Published: February 2007

A proper orthogonal decomposition (POD) analysis and low-dimensional modelling of thermally driven two-dimensional flow of air in a horizontal rotating cylinder, subject to the Boussinesq approximation, is considered. The problem is unsteady due to the harmonic nature of the gravitational buoyancy force with respect to the rotating observer and is characterized by four dimensionless numbers: gravitational Rayleigh number (Rag), the rotational Rayleigh number (RaΩ), the Taylor number (Ta) and Prandtl number (Pr). The data for the POD analysis are obtained by numerical integration of the governing equations of mass, momentum and energy. The POD is applied to the computational data for RaΩ varying in the range 102–106 while Rag and Pr are fixed at 105 and 0.71 respectively. The ratio of Ta to RaΩ is fixed at 100 so that the results apply to physically realistic situations. A new criterion, in the form of appropriately defined error norms, for assessing the truncation error of the POD expansion is proposed. It is shown that these error norms reflect the accuracy of the POD-based reconstructions of a given data ensemble better than the widely employed average energy criterion. The translational symmetry in both space and time of the pair of modes having degenerate (equal) eigenvalues confirms the presence of travelling waves in the flow for several different RaΩ values. The shifts in space and time of the structure of the degenerate modes are utilized to estimate the wave speeds in a given direction. The governing equations for the fluctuations are derived and low-dimensional models are constructed by employing a Galerkin procedure. For each of the five values of RaΩ, the low-dimensional models yield accurate qualitative as well as quantitative behaviour of the system. Sufficient modes are included in the low-dimensional models so that the modelling of the unresolved scales of motion is not needed to stabilize their solution. Not more than 20 modes are required in the low-dimensional models to accurately model the system dynamics. The ability of low-dimensional models to accurately predict the system behaviour for a set of parameters different from those from which they were constructed is also examined.
Vortices in oscillating spin-up
Authors: WELLS M. G. , CLERCX H. J. H. , VAN HEIJST G. J. F.
Published: February 2007

Laboratory experiments and numerical simulations of oscillating spin-up in a square tank have been conducted to investigate the production of small-scale vorticity near the no-slip sidewalls of the container and the formation and subsequent decay of wall-generated quasi-two-dimensional vortices. The flow is made quasi-two-dimensional by a steady background rotation, and a small sinusoidal perturbation to the background rotation leads to the periodic formation of eddies in the corners of the tank by the roll-up of vorticity generated along the sidewalls. When the oscillation period is greater than the time scale required to advect a full-grown corner vortex to approximately halfway along the sidewall, dipole structures are observed to form. These dipoles migrate away from the walls, and the interior of the tank is continually filled with new vortices. The average size of these vortices appears to be largely controlled by the initial formation mechanism. Their vorticity decays from interactions with other stronger vortices that strip off filaments of vorticity, and by Ekman pumping at the bottom of the tank. Subsequent interactions between the weaker ‘old’ vortices and the ‘young’ vortices result in the straining, and finally the destruction, of older vortices. This inhibits the formation of large-scale vortices with diameters comparable to the size of the container.

The laboratory experiments revealed a k−5/3 power law of the energy spectrum for small-to-intermediate wavenumbers. Measurements of the intensity spectrum of a passive scalar were consistent with the Batchelor prediction of a k−1 power law at large wavenumbers. Two-dimensional numerical simulations, under similar conditions to those in the experiments (with weak Ekman decay), were also performed and the simultaneous presence of a k−5/3 and k−3−ζ (with 0 < ζ « 1) power spectrum is observed, with the transition occurring at the wavenumber at which vorticity is injected from the viscous boundary layer into the interior. For higher Ekman decay rates, steeper spectra are obtained for the large wavenumber range, with ζ = O(1) and proportional to the Ekman decay rate. Movies are available with the online version of the paper.
Amplification of three-dimensional perturbations during parallel vortex–cylinder interaction
Authors: LIU X. , MARSHALL J. S.
Published: February 2007

A computational study has been performed to examine the amplification of three-dimensional flow features as a vortex with small-amplitude helical perturbations impinges on a circular cylinder whose axis is parallel to the nominal vortex axis. For sufficiently weak vortices with sufficiently small core radius in an inviscid flow, three-dimensional perturbations on the vortex core are indefinitely amplified as the vortex wraps around the cylinder front surface. The paper focuses on the effect of viscosity in regulating amplification of three-dimensional disturbances and on assessing the ability of two-dimensional computations to accurately model parallel vortex–cylinder interaction problems. The computations are performed using a multi-block structured finite-volume method for an incompressible flow, with periodic boundary conditions along the cylinder axis. Growth of three-dimensional flow features is examined using a proper-orthogonal decomposition of the Fourier-transformed vorticity field in the azimuthal and axial directions. The interaction is examined for different axial wavelengths and amplitudes of the initial helical vortex waves and for three different Reynolds numbers.
An epidemiological investigation of affective disorders with a population-based cohort of 1023 adults with intellectual disabilities
Authors: COOPER SALLY-ANN , SMILEY ELITA , MORRISON JILLIAN , WILLIAMSON ANDREW , ALLAN LINDA
Published: February 2007

Background. Intellectual disabilities (ID) are common and lifelong. People with ID have health inequalities compared with the general population, but little is known about the epidemiology of affective disorders in this population. This study was undertaken to determine the point prevalence of affective disorders, and to investigate factors associated with depression.

Method. This population-based study (n=1023) included comprehensive individual assessments with each person. A two-stage process was used for diagnosis of affective disorders. Factors independently associated with depression were investigated through logistic regression analysis.

Results. The point prevalence was higher than that reported previously for the general population; DC-LD yielded 3·8% for depression and 0·6% for mania. Additionally, 1·0% had bipolar disorder currently in remission, and 0·1% first episode of mania currently in remission. Similar to general population findings, depression was associated with female gender, smoking, number of preceding family physician appointments, and preceding life events. Important differences were the association of not having a hearing impairment, and the trends for not living in deprived areas, and being married. Unlike general population findings, not having daytime occupation and obesity were not independently associated; nor was previous long-stay hospital residence, severity of ID, or sensory impairments.

Conclusions. This study has found a high point prevalence of affective disorders in adults with ID. The factors associated with depression have differences to general population findings. An understanding of this is important in order to develop appropriate interventions, public strategy and policy, to reduce existing health inequalities.
Identification and treatment of anaemia in older patients
Authors: Osborne WL , Pemberton LC , Hanley JP
Published: February 2007

The World Health Organization's definition of anaemia is a haemoglobin level of less than 13g/dL for men and less than 12g/dL for women. Haemoglobin levels have been shown to decline with age, making anaemia a relatively common problem among older people. Because of this fall in haemoglobin with age, there has been some debate about whether an age-related reference range should be used. However, most clinicians believe that, because of the association between anaemia and increased risk of morbidity, mortality and hospitalization, the normal haemoglobin range should not be lowered for older people.
Incident in Arles: Regionalism, Resistance and the Case of the Statue of Frédéric Mistral
Authors: FREEMAN KIRRILY
Published: February 2007

On 11 October 1941 the Vichy government passed legislation mandating the dismantling and smelting of French bronze statues and monuments in the public domain. Crippled by copper shortages and bound by the terms of the Franco-German armistice, the etat français sought to ‘mobilise’ all potential sources of non-ferrous metals, including public statuary. The statue of Mistral in Arles was one of the monuments that were dismantled. The destruction of this tribute to the Provençal poet and founder of the Félibrige sparked considerable protest and opposition, but from an unusual quarter – supporters of Pétain's National Revolution. The case of the destruction of the statue of Mistral in Arles reveals the intersection of regionalism and resistance in wartime France and challenges many of our perceptions about both these movements.

Ame de Mon PaysAme éternellement renaissanteAme joyeuse, fière et viveQui hennis dans le bruit du Rhône et de son vent!Ame des bois pleins d'harmonieEt des calanques pleines de soleilDe la patrie, âme pieuseJe t'appelle! Incarne-toi dans mes vers provençaux!1
A Flight of Fantasy? Portugal and the First Attempt to Enlarge the European Economic Community, 1961–1963
Authors: LEITÃO NICOLAU ANDRESEN
Published: February 2007

This article explains the position of Portugal during the first attempt to enlarge the European Economic Community in 1961–3. It first makes clear the motives behind the Portuguese government's policy option in favour of EEC associate membership and future entry. Next, it analyses the attitude of the EEC members and Portugal's EFTA partners to this policy option. The article concludes that such a policy was condemned to failure, due to the authoritarian nature of the Portuguese regime and the country's colonial policy, and that, had the negotiations progressed, Lisbon would probably have had to opt in favour of a provisional agreement.
REDUCING THE RISKS OF A VACUUM DELIVERY
Authors: VACCA ALDO
Published: February 2007

Evidence-based reviews and practice guidelines have identified a number of risk factors associated with vacuum assisted delivery (VAD) that may result in adverse effects on the newborn infant, injuries to the mother's genital tract, and difficulty or failure of the procedure. In addition, clinical circumstances that predispose to increased risk, such as the use of the vacuum extractor for rotational and mid-cavity procedures, have been highlighted as possible avoidable factors. Although there is general agreement that success of vacuum delivery depends on the knowledge, experience and skill of the operator, system analyses of adverse outcomes often reveal inadequate training as a major contributing factor. It is beyond the scope of this review to present the detailed knowledge and technical skills required for correct use of the vacuum extractor. A variety of teaching resources is available for this purpose and practitioners who wish to obtain more information are referred to them.
Ensemble‐mean dynamics of the ENSO recharge oscillator under state‐dependent stochastic forcing
Authors: Jin Fei‐Fei , Lin L. , Timmermann A. , Zhao J.
Published: February 2007

In this paper, the conceptual recharge oscillator model for the El Niño‐Southern Oscillation phenomenon (ENSO) is utilized to study the influence of fast variability such as that associated with westerly wind bursts (WWB) on dynamics of ENSO and predictability. The ENSO‐WWB interaction is simply represented by stochastic forcing modulated by ENSO‐related sea surface temperature (SST) anomalies. An analytical framework is developed to describe the ensemble‐mean dynamics of ENSO under the stochastic forcing. Numerical ensemble simulations verify the main results derived from the analytical ensemble‐mean theory: the state‐dependent stochastic forcing enhances the instability of ENSO and its ensemble spread, generates asymmetry in the predictability of the onsets of cold and warm phases of ENSO, and leads to an ensemble‐mean bias that may eventually contribute to a climate mean state bias.
Imaging slow failure in triaxially deformed Etna basalt using 3D acoustic‐emission location and X‐ray computed tomography
Authors: Benson Philip M. , Thompson Ben D. , Meredith Philip G. , Vinciguerra Sergio , Young R. Paul
Published: February 2007

We have deformed basalt from Mount Etna (Italy) in triaxial compression tests under an effective confining pressure representative of conditions under a volcanic edifice (40 MPa), and at a constant strain rate of 5 × 10−6 s−1. Despite containing a high level of pre‐existing microcrack damage, Etna basalt retains a high strength of 475 MPa. We have monitored the complete deformation cycle through contemporaneous measurements of axial strain, pore volume change, compressional wave velocity change and acoustic emission (AE) output. We have been able to follow the complete evolution of the throughgoing shear fault without recourse to any artificial means of slowing the deformation. Locations of AE events over time yields an estimate of the fault propagation velocity of between 2 and 4 mm.s−1. We also find excellent agreement between AE locations and post‐test images from X‐ray microtomography scanning that delineates deformation zone architecture.
Incremental accretion of a sandy reef island over the past 3000 years indicated by component‐specific radiocarbon dating
Authors: Woodroffe Colin D. , Samosorn Bongkoch , Hua Quan , Hart Deirdre E.
Published: February 2007

Low‐lying reef islands appear particularly threatened by anticipated sea‐level rise, and determining how they formed and whether they are continuing to accumulate sediment is essential for their sustainable management. Depositional chronology of Warraber Island, a small sand cay in Torres Strait, Australia, is re‐examined based on AMS radiocarbon dating of specific skeletal components. Whereas radiometric dating of bulk sand samples indicated one or more discrete phases of mid‐late Holocene deposition, component‐specific AMS radiocarbon dating of sand grains indicates sustained incremental growth over the past 3000 years. Ages on gastropods that lived on the reef flat around the island indicate continuing sediment production and island progradation, in contrast to bulk ages and other components produced at greater distances. Growth of sand cays depends on the rate and pattern of sediment supply, which are functions of the local ecology of the surrounding reef and reef flat, and hydrodynamic constraints.
Negative inotropic effects of tumour necrosis factor‐α and interleukin‐1β are ameliorated by alfentanil in rat ventricular myocytes
Authors: Duncan D J , Hopkins P M , Harrison S M
Published: February 2007

Background and purpose:

Serum levels of tumour necrosis factor‐α (TNF‐α) and interleukin‐1β (IL‐1β) increase during an inflammatory response and have been reported to induce a negative inotropic effect on the myocardium. Alfentanil, an opioid analgesic often used in the critical care of patients with sepsis, has been shown to enhance ventricular contractility. This study characterised the effects of TNF‐α and IL‐1β on contraction and the Ca2+ transient and investigated whether depressed ventricular function was ameliorated by alfentanil.

Experimental approach:

Isolated rat ventricular myocytes were loaded with fura‐2 and electrically stimulated at 1 Hz. Contraction and Ca2+ transients were measured after 60, 120 and 180 min incubations in TNF‐α (0.05 ng ml−1) and IL‐1β (2 ng ml−1). The effects of 10 μM alfentanil on contractility and Ca2+ transients of TNF‐α and IL‐1β treated cells were determined.

Key results:

After 180 min of TNF‐α and IL‐1β treatment, the amplitude of contraction, the Ca2+ transient and sarcoplasmic reticulum (SR) Ca2+ content were significantly reduced. Alfentanil significantly increased contraction of TNF‐α and IL‐1β treated cells via a small increase in the Ca2+ transient and a larger increase in myofilament Ca2+ sensitivity, effects that were not blocked by 10 μM naloxone, a broad spectrum opioid receptor antagonist.

Conclusions and implications:

TNF‐α and IL‐1β induce a significant negative inotropic effect on ventricular myocytes in a time dependent manner through disruption of SR Ca2+ handling and the Ca2+ transient. This negative inotropic effect was ameliorated by alfentanil, but this response may not be mediated via opioid receptors.

British Journal of Pharmacology (2007) 150, 720–726. doi:10.1038/sj.bjp.0707147
The importance of baseline in identifying 8‐OH‐DPAT‐induced effects on prepulse inhibition in rats
Authors: Gogos A , van den Buuse M
Published: February 2007

Background and purpose:

Prepulse inhibition (PPI) of the acoustic startle response is a model of sensorimotor gating which is disrupted in schizophrenia and other mental illnesses. We and others have shown that treatment with the 5‐hydroxytryptamine‐1A (5‐HT1A) receptor agonist, 8‐OH‐DPAT, disrupts PPI in rats. In the present study, we highlight the importance of baseline levels on the effect of 8‐OH‐DPAT on PPI.

Experimental approach:

Adult male and female Sprague‐Dawley rats were gonadectomised. These rats were treated with saline, 0.02 and 0.5 mg kg‐1 of 8‐OH‐DPAT using a random‐sequence, repeated‐measures protocol. The rats were allocated into high and low baseline groups depending on their baseline PPI observed after saline treatment.

Key results:

Treatment with 0.5 mg kg‐1 of 8‐OH‐DPAT significantly disrupted PPI in both male and female rats. In male rats only, 0.02 mg kg‐1 8‐OH‐DPAT caused a small, but significant, increase in PPI. When these male rats were allocated to either a high or low baseline PPI group, 0.5 mg kg‐1 8‐OH‐DPAT disrupted PPI in the high baseline group only. In contrast, treatment with 0.02 mg kg‐1 8‐OH‐DPAT increased PPI only in the low baseline PPI group. There were no changes in the effect of 8‐OH‐DPAT administration in female rats when they were divided into high and low baseline PPI groups.

Conclusions and implications:

The level of baseline PPI is an important variable that can influence the direction of drug effects induced by 8‐OH‐DPAT. The explanation for this phenomenon could be differential activation of pre‐ and postsynaptic 5‐HT1A receptors.

British Journal of Pharmacology (2007) 150, 750–757. doi:10.1038/sj.bjp.0707148
Genetic and pharmacological approaches to evaluate the interaction between the cannabinoid and cholinergic systems in cognitive processes
Authors: Bura S A , Castañé A , Ledent C , Valverde O , Maldonado R
Published: February 2007

Background and purpose:

The objective of this study was to investigate the possible interactions between the cannabinoid and cholinergic systems in memory and learning processes by using genetic and pharmacological approaches in two different behavioural models, the active avoidance and the object recognition test.

Experimental approach:

The effects induced by nicotine, physostigmine and scopolamine were studied in CB1receptor knockout and wild‐type mice in the active avoidance paradigm. In addition, the effects of pretreatment with the CB1receptor antagonist rimonabant were evaluated on the responses induced by nicotine in the active avoidance and the object recognition tasks in wild‐type mice.

Key results:

Nicotine (0.5 mgkg–1s.c.) did not modify the performance of CB1knockout and wild‐type mice in this model, whereas scopolamine (0.5 mgkg–1i.p.) impaired the performance in both genotypes. Physostigmine (0.1 mgkg–1i.p.) increased the active avoidance performance in wild‐type but not in CB1knockout mice. Rimonabant (0.3, 1, 3, and 10 mgkg–1) did not modify the performance in the active avoidance test, given alone or co‐administered with nicotine. In contrast, nicotine enhanced the performance in the object recognition task but this response was attenuated by rimonabant co‐administration.

Conclusions and implications:

The present findings revealed that the cognitive effects of nicotine and physostigmine were attenuated in the absence of CB1receptor activity. Scopolamine effects were independent from CB1receptors.

British Journal of Pharmacology(2007)150, 758–765. doi:10.1038/sj.bjp.0707152
Nuclear Receptors
Authors: Alexander S. P. H. , Mathie A , Peters J. A.
Published: February 2007

ALEXANDER, S.P.H., MATHIE, A. & PETERS, J.A. (2007). Guide to Receptors and Channels (GRAC), 2nd edition (2007 revision). Br. J. Pharmacol., 150 (Suppl. 1), S1–S168.
Enzymes
Authors: Alexander S. P. H. , Mathie A , Peters J. A.
Published: February 2007

ALEXANDER, S.P.H., MATHIE, A. & PETERS, J.A. (2007). Guide to Receptors and Channels (GRAC), 2nd edition (2007 revision). Br. J. Pharmacol., 150 (Suppl. 1), S1–S168.
Study of a colliding laser-produced plasma by analysis of time- and space-resolved image spectra
Authors: Luna H. , Kavanagh K. D. , Costello J. T.
Published: February 2007

The interaction of two counterpropagating laser-produced plasmas was studied using simultaneous imaging and spectroscopic techniques. Spectrally filtered time-gated intensified charge coupled device imaging was used to obtain information about the spatial dynamics and temporal evolution of the collision process, while time-resolved imaging spectroscopy was used to determine the spatial and temporal distributions of electron temperature and density within the interaction region. We examine specifically the interaction of plasmas whose parameters match those typically used in pulsed laser deposition of thin films. These low temperature plasmas are highly collisional leading to the creation of a pronounced stagnation layer in the interaction region.
Joule heating as a technique for obtaining uncoupled soft and hard magnetic phases in a Finemet alloy
Authors: Gupta P. , Gupta A. , Franco V. , Conde A.
Published: February 2007

A detailed study on the microstructural evolution of the Fe73.9Cu0.9Nb3.1Si13.2B8.9 (Finemet) alloy upon Joule heating and its correlation with the magnetic properties is reported. Mössbauer spectroscopy suggests the coexistence of soft nonstoichiometric Fe3Si and hard iron boride magnetic phases. The uncoupled magnetic character of these phases is evidenced by dc-hysteresis loop measurements. X-ray diffraction results display an excellent agreement with the magnetic characterization. The magnetic contribution of the soft phase has been decreased from 70% to 10% with increasing annealing current and time. The switching field value for the soft magnetic phase is 50A∕m, which is very less as compared to 2000A∕m, for the hard magnetic phase. Existence of uncoupled soft and hard magnetic phases makes these systems suitable for use as magnetic labels.
Analytic determination of n, κ, and d of an absorbing film from polarimetric data in the thin-film limit
Authors: Kim I. K. , Aspnes D. E.
Published: February 2007

We obtain a solution of the three-phase model in the limit d∕λ⪡1, where the complex refractive index ñ=n+iκ and thickness d of an isotropic film on an isotropic substrate are given analytically at any single wavelength λ from polarimetric data Δρ∕ρ and ΔR∕R, where ρ is the complex reflectance ratio and R is either the p- or s-polarized reflectance. We describe several procedures for extending the range of validity of the solution. Analysis of correlations shows that the uncertainty δ(ΔR∕R) of ΔR∕R is significantly more important than the δ(Δρ∕ρ) of Δρ∕ρ, which allows us to obtain an expression for the uncertainties δn, δκ, and δd of n, κ, and d, and to identify conditions that optimize the determination of the layer parameters. We find that the relative uncertainties δn∕n and δd∕d are not equal, as would be expected if they were determined by the optical thickness nd measured by ellipsometry, but that ΔR∕R breaks the connection. We verify our results by measurements of H2O reversibly physisorbed on oxidized GaAs, finding, for example, that for our conditions δκ is determined more accurately than δn, and δn more accurately than δd. These data and model calculations show that fluctuations in parameters, particularly d, are asymmetric, leading in principle to inaccurate average values. However, we show that the importance of the ΔR∕R data together with the remaining high correlation between n and d allows us to define a characteristic curve that can be used to correct the results for this nonlinearity. Finally, we extend our analysis to determine the orthogonal linear combinations of n, κ, and d that the data actually determine, which explains why the data fit the characteristic curve so well. Our results will be useful in various contexts for the analysis of films less than 1nm thick, for example, in applications involving preparation of next-generation electronic and optoelectronic devices with complicated multilayer structures, real-time control of deposition, and the identification of physisorbed and chemisorbed layers on the monolayer scale.
Response to “Comment on ‘Magnetic field effects on gas discharge plasmas’ ” [Phys. Plasmas 13, 063511 (2006)]
Authors: Sternberg Natalia , Godyak Valery , Hoffman Daniel
Published: February 2007

It is well known that the plasma equations, with or without a magnetic field present, have a singularity at the point where the ions reach the ion sound speed. In his comment to our paper, J. E. Allen [Phys. Plasmas 14, 024701 (2007)] tries to explain that phenomenon by claiming that the Boltzmann electron distribution must hold near the boundary even for magnetized plasmas. His claim, however, contradicts the theoretical and numerical results of our paper, the results he seems to agree with.
Fiber-based architectures for organic photovoltaics
Authors: Liu Jiwen , Namboothiry Manoj A. G. , Carroll David L.
Published: February 2007

Using poly(3-hexylthiophene) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 bulk-heterojunction blends as the absorbing material, organic photovoltaic devices have been fabricated onto multimode optical fibers. The behavior of the short circuit current density, filling factor, and open circuit voltage as the angle of the incident light onto the cleaved fiber face is varied suggests that the evanescent field at the interface between the fiber and the transparent contact may play a role in coupling light from the fiber into the device. Further, optical loss into the device increases as the fiber diameter decreases.
Supersymmetric vertex models with domain wall boundary conditions
Authors: Zhao Shao-You , Zhang Yao-Zhong
Published: February 2007

By means of the Drinfeld twists, we derive the determinant representations of the partition functions for the gl(1∣1) and gl(2∣1) supersymmetric vertex models with domain wall boundary conditions. In the homogeneous limit, these determinants degenerate to simple functions.
Transport characterization of the magnetic anisotropy of (Ga,Mn)As
Authors: Pappert K. , Hümpfner S. , Wenisch J. , Brunner K. , Gould C. , Schmidt G. , Molenkamp L. W.
Published: February 2007

The rich magnetic anisotropy of compressively strained (Ga,Mn)As has attracted great interest recently. Here the authors discuss a sensitive method to visualize and quantify the individual components of the magnetic anisotropy using transport. A set of high resolution transport measurements is compiled into color coded resistance polar plots, which constitute a fingerprint of the symmetry components of the anisotropy. As a demonstration of the sensitivity of the method, they show that these typically reveal the presence of both the [1¯10] and the [010] uniaxial magnetic anisotropy component in (Ga,Mn)As layers, even when most other techniques reveal only one of these components.
Deformation potential carrier-phonon scattering in semiconducting carbon nanotube transistors
Authors: Pennington G. , Goldsman N. , Akturk A. , Wickenden A. E.
Published: February 2007

Theoretical calculations of carrier transport in semiconducting single-walled carbon nanotubes are compared with recent experiments. Considering carrier-phonon scattering, a deformation potential coupling constant of 14eV is determined. Theory predicts the low-field mobility, conductance, and on resistance of field-effect transistors as a function of nanotube diameter and temperature. When the device is in the on state, the mean free path (Lm-on) varies linearly with tube diameter and inversely with temperature. Intersubband scattering is found to strongly decrease Lm-on when a few subbands are occupied.
Unstable amplitude and noisy image induced by tip contamination in dynamic force mode atomic force microscopy
Authors: Nie H.-Y. , McIntyre N. S.
Published: February 2007

Liquid 1-decanethiol was confined on an atomic force microscope (AFM) tip apex and the effect was investigated by measuring amplitude-distance curves in dynamic force mode. Within the working distance in the dynamic force mode AFM, the thiol showed strong interactions bridging between a gold-coated probe tip and a gold-coated Si substrate, resulting in unstable amplitude and noisy AFM images. We show that under such a situation, the amplitude change is dominated by the extra forces induced by the active material loaded on the tip apex, overwhelming the amplitude change caused by the geometry of the sample surface, thus resulting in noise in the image the tip collects. We also show that such a contaminant may be removed from the apex by pushing the tip into a material soft enough to avoid damage to the tip.
Fermi level shift in GaInNAsSb∕GaAs quantum wells upon annealing studied by contactless electroreflectance
Authors: Kudrawiec R. , Yuen H. B. , Bank S. R. , Bae H. P. , Wistey M. A. , Harris James S. , Motyka M. , Misiewicz J.
Published: February 2007

Contactless electroreflectance (CER) spectroscopy has been applied to study band bending in GaInNAsSb∕GaAs quantum well (QW) structures. It has been observed that CER features significantly changes upon annealing: the period of GaAs-related Franz-Keldysh oscillations increases; intensities of excited QW transitions rose compared to the intensity of the fundamental QW transition. The observed changes in CER spectra have been explained by a shift of the Fermi level in the GaInNAsSb layer: the defect states in as-grown GaInNAsSb tend to pin the Fermi level at an energy characteristic for these defects; annealing removes defects from this material and effectively shifts the Fermi level to the conduction band.
Lifetime of anode polymer in magnetically insulated ion diodes for high-intensity pulsed ion beam generation
Authors: Zhu X. P. , Dong Z. H. , Han X. G. , Xin J. P. , Lei M. K.
Published: February 2007

Generation of high-intensity pulsed ion beam (HIPIB) has been studied experimentally using polyethylene as the anode polymer in magnetically insulated ion diodes (MIDs) with an external magnetic field. The HIPIB is extracted from the anode plasma produced during the surface discharging process on polyethylene under the electrical and magnetic fields in MIDs, i.e., high-voltage surface breakdown (flashover) with bombardments by electrons. The surface morphology and the microstructure of the anode polymer are characterized using scanning electron microscopy and differential scanning calorimetry, respectively. The surface roughening of the anode polymer results from the explosive release of trapped gases or newly formed gases under the high-voltage discharging, leaving fractured surfaces with bubble formation. The polyethylene in the surface layer degrades into low-molecular-weight polymers such as polyethylene wax and paraffin under the discharging process. Both the surface roughness and the fraction of low molecular polymers apparently increase as the discharging times are prolonged for multipulse HIPIB generation. The changes in the surface morphology and the composition of anode polymer lead to a noticeable decrease in the output of ion beam intensity, i.e., ion current density and diode voltage, accompanied with an increase in instability of the parameters with the prolonged discharge times. The diode voltage (or surface breakdown voltage of polymer) mainly depends on the surface morphology (or roughness) of anode polymers, and the ion current density on the composition of anode polymers, which account for the two stages of anode polymer degradation observed experimentally, i.e., stage I which has a steady decrease of the two parameters and stage II which shows a slow decrease, but with an enhanced fluctuation of the two parameters with increasing pulses of HIPIB generation.
Nanoanalysis of crystalline properties of GaN thin film using tip-enhanced Raman spectroscopy
Authors: Matsui Ryota , Verma Prabhat , Ichimura Taro , Inouye Yasushi , Kawata Satoshi
Published: February 2007

Nanoscaled variation in crystalline properties was demonstrated through tip-enhanced Raman scattering (TERS) for a thin GaN sample, which apparently showed good and uniform crystalline properties at microscale in conventional micro-Raman scattering. The observation was attributed to the field enhancement and the super-resolution associated with the near-field technique. The enhancement factor of the TERS intensity was assessed to be larger than 2.8×104. Variations in crystalline properties were observed at spatial resolution beyond the diffraction limit of the probing light. The authors propose TERS to be an efficient technique for nanoscale characterization of crystalline properties for the nitride-based semiconductor devices.