bluuebunny/crossref_metadata_2025 huggingface dataset:
IntraerythrocyticPlasmodium falciparumutilize a broad range of serum-derived fatty acids with limited modification for their growth
Authors: MI-ICHI F. , KITA K. , MITAMURA T.
Published: June 2006

Plasmodium falciparumcauses the most severe form of malaria. Utilization of fatty acids in serum is thought to be necessary for survival of this parasite in erythrocytes, and thus characterization of the parasite fatty acid metabolism is important in developing a new strategy for controlling malaria. Here, we examined which combinations of fatty acids present in human serum support the continuous culture ofP.falciparumin serum-free medium. Metabolic labelling and gas chromatography analyses revealed that, despite the need for particular fatty acids for the growth of intraerythrocyticP.falciparum, it can metabolize a broad range of serum-derived fatty acids into the major lipid species of their membranes and lipid bodies. In addition, these analyses showed that the parasite's overall fatty acid composition reflects that of the medium, although the parasite has a limited capacity to desaturate and elongate serum-derived fatty acids. These results indicate that thePlasmodiumparasite is distinct from most cells, which maintain their fatty acid composition by coordinatingde novobiosynthesis, scavenging, and modification (desaturation and elongation).
Time-series analysis of the risk factors for haemorrhagic fever with renal syndrome: comparison of statistical models
Authors: HU W. , MENGERSEN K. , BI P. , TONG S.
Published: June 2006

Three conventional regression models were compared using the time-series data of the occurrence of haemorrhagic fever with renal syndrome (HFRS) and several key climatic and occupational variables collected in low-lying land, Anhui Province, China. Model I was a linear time series with normally distributed residuals; model II was a generalized linear model with Poisson-distributed residuals and a log link; and model III was a generalized additive model with the same distributional features as model II. Model I was fitted using least squares whereas models II and III were fitted using maximum likelihood. The results show that the correlations between the HFRS incidence and the independent variables measured (i.e. difference in water level, autumn crop production and density of Apodemus agrarius) ranged from −0·40 to 0·89. The HFRS incidence was positively associated with density of A. agrarius and crop production, but was inversely associated with difference in water level. The residual analyses and the examination of the accuracy of the models indicate that model III may be the most suitable in the assessment of the relationship between the incidence of HFRS and the independent variables.
Simulation of CFCs in the North Atlantic Ocean using an adiabatically corrected ocean circulation model
Authors: Zhao Jun , Sheng Jinyu , Greatbatch Richard J. , Azetsu‐Scott Kumiko , Jones E. Peter
Published: June 2006

A three‐dimensional ocean circulation model is used to examine the uptake, spreading and interannual variability of chlorofluorocarbons (CFCs) in the North Atlantic Ocean during the 50‐year period from 1948 to 1997. The model is forced by climatological and North Atlantic Oscillation (NAO) related monthly mean surface forcing, and a realistic, time‐varying air‐sea flux of CFCs. Different from previous studies, the model uses the modified semiprognostic method to correct for systematic bias, leading to improvements in the modeled ocean circulation near the western boundary. Comparisons are made between simulated concentrations and observations made along three World Ocean Circulation Experiment transects, and between the simulated inventory of CFCs in the Labrador Sea and estimates based on observations. The model reproduces the general structure of the observed concentrations, including the concentration maxima associated with Labrador Sea Water (LSW) near the western boundary, although quantitative comparisons indicate that the model CFC concentrations associated with LSW are generally too high. The equatorward spreading rate of LSW is estimated from CFC effective age and found to be about 1.3 cm s−1, in agreement with observational estimates. We also discuss the close relationship between the NAO and interannual variability in the uptake and inventory of CFCs in the Labrador Sea, and the spreading of CFCs along the western boundary.
Arctic decadal variability from an idealized atmosphere‐ice‐ocean model: 2. Simulation of decadal oscillations
Authors: Dukhovskoy Dmitry , Johnson Mark , Proshutinsky Andrey
Published: June 2006

A simple model of the Arctic Ocean and Greenland Sea, coupled to a thermodynamic sea ice model and an atmospheric model, has been used to study decadal variability of the Arctic ice‐ocean‐atmosphere climate system. The motivating hypothesis is that the behavior of the modeled and ultimately the real climate system is auto‐oscillatory with a quasi‐decadal periodicity. This system oscillates between two circulation regimes: the Anticyclonic Circulation Regime (ACCR) and the Cyclonic Circulation Regime (CCR). The regimes are controlled by the atmospheric heat flux from the Greenland Sea and the freshwater flux from the Arctic Ocean. A switch regulating the intensity of the fluxes between the Arctic Ocean and Greenland Sea that depends on the interbasin gradient of dynamic height is implemented as a delay mechanism in the model. This mechanism allows the model system to accumulate the “perturbation” over several years. After the perturbation has been released, the system returns to its initial state. Solutions obtained from numerical simulations with seasonally varying forcing, for scenarios with high and low interaction between the regions, reproduced the major anomalies in the ocean thermohaline structure, sea ice volume, and freshwater fluxes attributed to the ACCR and CCR.
Incoherent scatter spectrum theory for modes propagating perpendicular to the geomagnetic field
Authors: Kudeki Erhan , Milla Marco
Published: June 2006

The collisional incoherent scatter spectral theory of Woodman is extended to the Te/Ti > 1 case by using its equivalent electron‐ and ion‐Gordeyev integrals in existing collisionless spectral models. A collisional spectral model for Te/Ti > 1 is needed in the interpretation of F region incoherent scatter returns obtained at small magnetic aspect angles.
Huygens entry emission: Observation campaign, results, and lessons learned
Authors: Lorenz Ralph D. , Witasse Olivier , Lebreton Jean‐Pierre , Blancquaert Thierry , de Pater Imke , Mazoue Franck , Roe Henry , Lemmon Mark T. , Burratti Bonnie J. , Holmes Shadrian , Noll Keith
Published: June 2006

An attempt was made to observe from Earth the emission from the shock layer and “meteor trail” formed during the Huygens probe's hypersonic entry into Titan's atmosphere. Although many observations were wiped out by weather or in‐orbit failure, two observations constrain the emission from the entry. Several important lessons for future observations of spacecraft and other entries can be drawn.
Using chemical tracers in hillslope soils to estimate the importance of chemical denudation under conditions of downslope sediment transport
Authors: Mudd Simon Marius , Furbish David Jon
Published: June 2006

We present a model of hillslope soils that couples the evolution of topography, soil thickness, and the concentration of constituent soil phases, defined as unique components of the soil with collective mass equal to the total soil mass. The model includes both sediment transport and chemical denudation. A simplified two‐phase model is developed; the two phases are a chemically immobile phase, which has far lower solubility than the bulk soil and is not removed through chemical weathering (for example, zircon grains), and a chemically mobile phase that may be removed from the system through chemical weathering. Chemical denudation rates in hillslope soils can be measured using the concentration of immobile elements, but the enrichment of these immobile elements is influenced by spatial variations in chemical denudation rates and spatial variations in the chemical composition of a soil's parent material. These considerations cloud the use of elemental depletion factors and cosmogenic nuclide‐based total denudation rates used to identify the relationship between physical erosion and chemical weathering if these techniques do not account for downslope sediment transport. On hillslopes where chemical denudation rates vary in space, estimates of chemical denudation using techniques that do not account for downslope sediment transport and spatial variations in chemical denudation rates may be adequate where the chemical denudation rate is a significant fraction of the total denudation rate but are inadequate in regions where chemical weathering rates are small compared to the total denudation rate. We also examine relationships between transient mechanical and chemical denudation rates. Soil particle residence times may affect chemical weathering rates, and the relationship between total landscape‐lowering rates and soil particle residence times can thus be quantified.
Sensitivity of the thermohaline circulation to Arctic Ocean runoff
Authors: Rennermalm Asa K. , Wood Eric F. , Déry Stephen J. , Weaver Andrew J. , Eby Michael
Published: June 2006

Arctic Ocean river runoff increases over the 20th century raise concerns of the potential impact it may have on the thermohaline circulation (THC) and thus global climate. This study investigates how changes in Arctic river discharge may control THC by a series of experiments with an intermediate complexity global climate model. The experiments show an inverse relationship between THC strength and changes to riverine freshwater discharge, similar to the response of THC to surface freshening of the North Atlantic. Arctic Ocean freshwater export and volume were more sensitive to river runoff than sea ice export. A strong linear relationship between the THC strength and the steric height gradient (depth integrated density anomaly and an important driver for the western boundary current) suggests that the Arctic freshwater pools and fluxes are very effective in translating changes in runoff to THC strength by regulating the ocean water density in the North Atlantic.
Novel therapeutic strategies for reducing arterial stiffness
Authors: McEniery Carmel M
Published: June 2006

British Journal of Pharmacology (2006) 148, 881–883. doi:10.1038/sj.bjp.0706805
Adenosine A2Areceptors play a role in the pathogenesis of hepatic cirrhosis
Authors: Chan Edwin S L , Montesinos Maria Carmen , Fernandez Patricia , Desai Avani , Delano David L , Yee Herman , Reiss Allison B , Pillinger Michael H , Chen Jiang‐Fan , Schwarzschild Michael A , Friedman Scott L , Cronstein Bruce N
Published: June 2006

Adenosine is a potent endogenous regulator of inflammation and tissue repair. Adenosine, which is released from injured and hypoxic tissue or in response to toxins and medications, may induce pulmonary fibrosis in mice, presumablyviainteraction with a specific adenosine receptor. We therefore determined whether adenosine and its receptors contribute to the pathogenesis of hepatic fibrosis.

As in other tissues and cell types, adenosine is releasedin vitroin response to the fibrogenic stimuli ethanol (40 mg dl−1) and methotrexate (100 nM).

Adenosine A2Areceptors are expressed on rat and human hepatic stellate cell lines and adenosine A2Areceptor occupancy promotes collagen production by these cells. Liver sections from mice treated with the hepatotoxins carbon tetrachloride (CCl4) (0.05 ml in oil, 50 : 50 v : v, subcutaneously) and thioacetamide (100 mg kg−1in PBS, intraperitoneally) released more adenosine than those from untreated mice when culturedex vivo.

Adenosine A2Areceptor‐deficient, but not wild‐type or A3receptor‐deficient, mice are protected from development of hepatic fibrosis following CCl4or thioacetamide exposure.

Similarly, caffeine (50 mg kg−1 day−1, po), a nonselective adenosine receptor antagonist, and ZM241385 (25 mg kg−1bid), a more selective antagonist of the adenosine A2Areceptor, diminished hepatic fibrosis in wild‐type mice exposed to either CCl4or thioacetamide.

These results demonstrate that hepatic adenosine A2Areceptors play an active role in the pathogenesis of hepatic fibrosis, and suggest a novel therapeutic target in the treatment and prevention of hepatic cirrhosis.

British Journal of Pharmacology(2006)148, 1144–1155. doi:10.1038/sj.bjp.0706812
Tolerance to cannabinoid response on the myenteric plexus of guinea‐pig ileum and human small intestinal strips
Authors: Guagnini Fabio , Cogliati Paola , Mukenge Sylvain , Ferla Gianfranco , Croci Tiziano
Published: June 2006

We studied tolerance to cannabinoid agonist action by comparing the in vitro inhibition of electrically evoked contractions of longitudinal muscle from small intestine of human and guinea‐pig (myenteric plexus preparations) after 48‐h incubation with the synthetic agonist (+) WIN 55,212‐2. We also investigated the intrinsic response to the selective cannabinoid CB1 receptor antagonist rimonabant in control and tolerant strips.

(+) WIN 55,212‐2 inhibited guinea‐pig (IC50 4.8 nM) and human small intestine (56 nM) contractions with similar potency before or after 48‐h incubation in drug‐free conditions; this effect was competitively antagonized by rimonabant (pA2, 8.4, 8.2). A 48‐h preincubation with (+) WIN 55,212‐2, but not with (−) WIN 55,212‐3, completely abolished the acute agonist response in both tissue preparations. The opiate K‐receptor agonist U69593 inhibited human small intestine contractions with a similar potency in control and strips tolerant to (+) WIN 55,212‐2, IC50 39 and 43 nM.

Unlike human tissue, in guinea‐pig small intestine, which has a high level of endocannabinoids, rimonabant alone increased the twitches induced by the electrical field stimulation (EC50 100 nM) with a maximal effect of 123%.

In strips tolerant to (+) WIN 55,212‐2, rimonabant markedly increased (155%) the electrical twitches in human ileum and in guinea‐pig myenteric plexus smooth muscle (133%).

This study shows tolerance can be induced to the cannabinoids' action in intestinal strips of human and guinea‐pig by long in vitro incubation with the agonist (+) WIN 55,212‐2.

British Journal of Pharmacology (2006) 148, 1165–1173. doi:10.1038/sj.bjp.0706813
Smectic order induced at homeotropically aligned nematic surfaces: A neutron reflection study
Authors: Lau Y. G. J. , Richardson Robert M. , Cubitt R.
Published: June 2006

Neutron reflection was used to measure the buildup of layers at a solid surface as the smectic phase is approached from higher temperatures in a nematic liquid crystal. The liquid crystal was 4-octyl-4′-cyanobiphenyl (8CB), and the solid was silicon with one of five different surface treatments that induce homeotropic alignment: (i) silicon oxide; (ii) a cetyltrimethylammonium bromide coating; (iii) an octadecyltrichlorosilane monolayer; (iv) an n-n-dimethyl-n-octadecyl-3- aminopropyltrimethyloxysilyl chloride monolayer; and (v) a lecithin coating. The development of surface smectic layers in the nematic phase of 8CB was followed by measuring specular reflectivity and monitoring the pseudo-Bragg peak from the layers. The scattering data were processed to remove the scattering from short-ranged smecticlike fluctuations in the bulk nematic phase from the specular reflection. The pseudo-Bragg peak at scattering vector Q∼0.2Å−1 therefore corresponded to the formation of long-range smectic layers at the surface. The amplitude of the smectic density wave decayed with increasing distance from the surface, and the characteristic thickness of this smectic region diverged as the transition temperature was approached. It was found that the characteristic thickness for some of the surface treatments was greater than the correlation length in the bulk nematic. The different surfaces gave different values of the smectic order parameter at the surface. This suggests that the interaction with the surface is significantly different from a “hard wall” which would give the same values of the smectic order parameter and penetration depths similar to the bulk correlation length. Comparison of the different surfaces also suggested that the strength and range of the surface smectic ordering may be varied independently.
Real-time detection of ambient aerosols using photothermal interferometry: Folded Jamin interferometer
Authors: Sedlacek Arthur J.
Published: June 2006

Work in our laboratory has been directed at the development of a new class of instrumentation that can directly measure ambient aerosol absorption through photothermal interferometry. The hallmark of this approach is its ability to directly measure aerosol absorption without interference from aerosol scattering since the signal originates from the thermal dissipation of the spectrally absorbed energy. While the principle of the photothermal technique for the detection of aerosols was demonstrated in the mid-1980s, this interferometric technique remains a laboratory technique largely due to sensitivity to mechanical vibrations and other environmental factors that result in unwanted signal interference and commensurate reduction in detection sensitivity. In order to realize its application outside the laboratory, a folded Jamin interferometer design has replaced both the traditional Mach-Zehnder and unfolded Jamin configurations. The folded Jamin affords many advantages, which include high degree of common mode noise rejection, insensitivity to rotation and translation of optical components, inherent double pass configuration, and compact size. In this article, we report on the performance of this optical configuration and present representative data for both absorbing and nonabsorbing aerosols.
Oxygen plasma treatment of gate metal in organic thin-film transistors
Authors: Han Keon-kook , Lee S. Woon , Lee Hong H.
Published: June 2006

Oxygen plasma treatment of metal gate surface is introduced as an effective method for improving the performance of the organic thin-film transistors with polymer dielectrics. The treatment results in about an order of magnitude increase in the on-off current ratio, bringing the ratio to the level of 106, and enabling a reduction in the threshold voltage. The treatment leads to the formation of an ultrathin metal oxide layer (<4.0nm) and a more wettable gate surface for subsequent polymer coating, both of which contribute to the enhancement in the device performance.
Light emission efficiency and dynamics in silicon-rich silicon nitride films
Authors: Dal Negro L. , Yi J. H. , Michel J. , Kimerling L. C. , Chang T.-W. F. , Sukhovatkin V. , Sargent E. H.
Published: June 2006

Light-emitting Si-rich silicon nitride (SRN) films were fabricated by plasma enhanced chemical vapor deposition followed by thermal annealing and the SRN external quantum efficiency was measured. The SRN light emission temperature dependence and recombination dynamics were also studied. Small emission thermal quenching from 4to330K with wavelength dependent, nanosecond recombination lifetime was observed. Light emission from SRN systems can provide alternative routes towards the fabrication of efficient Si-based optical devices.
Localized formation of InAs quantum dots on shallow-patterned GaAs(100)
Authors: Wang Zh. M. , Lee J. H. , Liang B. L. , Black W. T. , Kunets Vas. P. , Mazur Yu. I. , Salamo G. J.
Published: June 2006

Selective formation of InAs quantum dots on the sidewalls of mesa strips along both [01−1] and [011] directions of a GaAs(100) surface is demonstrated. This result is in sharp contrast to observations on traditionally deep-patterned substrates, where quantum dots are formed on top mesas and at bottom trenches. This distinction is explained kinetically and energetically. These results may encourage application of organized arrays of quantum dots.
Antiferromagnetic-coupling-induced magnetoresistance enhancement in Fex(TiO2)1−x films
Authors: Liu Hui , Mi W. B. , Li Z. Q. , Zhang D. X. , Wang Y. X. , Bai H. L. , Zheng R. K. , Ringer S. P.
Published: June 2006

Fe-incorporated amorphous TiO2 films with different Fe volume fractions of 0.46⩽x⩽0.76 were deposited by cosputtering iron and Ti targets in an Ar+O2 mixture. X-ray diffraction and x-ray photoelectron spectroscopy analyses give a structure of nanosized Fe particles embedded in amorphous TiO2 matrix for the Fex(TiO2)1−x films. Magnetic measurements show antiferromagnetic coupling between nanoscaled Fe granules when x<0.60. The magnetoresistance of Fe0.46(TiO2)0.54 is about −7.6% at room temperature, which increases dramatically with decreasing temperature below ∼100K and reaches −29.3% at 3K. This significant enhancement of magnetoresistance can be qualitatively explained by antiferromagnetic coupling between Fe granules.
Fully digital frequency stabilization of IR fiber-coupled laser
Authors: Jedlička Petr , Lazar Josef , Číp Ondřej
Published: June 2006

We present a stabilized semiconductor laser system designed to operate as a fiber-optic front-end master oscillator of a pulsed high-power iodine laser Prague Asterix Laser System (PALS). The replacement of the PALS master oscillator is a part of a broader effort to rebuild PALS into a laser generating shorter pulses with higher pulse power by the technique of optical parametric chirped pulse amplification. With an operating wavelength of 1315.15nm the stabilized laser master oscillator is based on a telecommunication single-frequency distributed feedback diode. The frequency stabilization is derived from transitions in thermally dissociated iodine. Locking to the selected transition is fully automatic and the control system employs a unique combination of control loops derived from temperature and absorption to overcome the problem of narrow locking range of a single absorption line.
Electronic structure and energetics of the quaternary hydride Li4BN3H10
Authors: Herbst J. F. , Hector L. G.
Published: June 2006

Li 4 B N 3 H 10 has been synthesized recently from LiNH2∕LiBH4 mixtures and its crystal structure determined. We have calculated the electronic structure of this complex hydride and investigated its thermodynamic stability and decomposition energetics. We find that its enthalpy of formation is −708kJ∕mole with respect to the elemental constituents and −8kJ∕mole relative to a 3:1 molar LiNH2∕LiBH4 mixture, in qualitative agreement with experiment. Reaction enthalpies computed for several decomposition pathways suggest Li4BN3H10→Li3BN2+12Li2NH+12NH3+4H2 as the likely dehydriding route.
Nd
3
+
-doped yttrium aluminum garnet crystal as a near-infrared pressure sensor for diamond anvil cells
Authors: Kobyakov S. , Kamińska A. , Suchocki A. , Galanciak D. , Malinowski M.
Published: June 2006

Pressure-induced shift of various luminescence lines of Nd3+-doped yttrium aluminum garnet crystal in the pressure range of 0–120kbars and temperatures between 10 and 300K is reported. Spectral positions of all these lines in the region of 900–960nm shift linearly towards lower energies with the pressure coefficient values from −0.01to−0.99cm−1∕kbar in the examined pressure range. Two of these lines have similar pressure coefficients than those of the R lines of Cr3+ in ruby. Therefore, they can be readily used for pressure calibration in diamond anvil cells.
Improvement of resistive memory switching in NiO using IrO2
Authors: Kim D. C. , Lee M. J. , Ahn S. E. , Seo S. , Park J. C. , Yoo I. K. , Baek I. G. , Kim H. J. , Yim E. K. , Lee J. E. , Park S. O. , Kim H. S. , Chung U-In , Moon J. T. , Ryu B. I.
Published: June 2006

For the development of resistive memory devices using NiO, improvements of several memory switching properties are required. In NiO memory cells with noble metal electrodes, broad dispersions of memory switching parameters are generally observed with continuous memory switchings. We report the improvements in minimizing the dispersions of all memory switching parameters using thin IrO2 layers between NiO and electrodes. The role of thin IrO2 layers on NiO growth and memory switching stabilization are discussed.
Ambipolar rubrene thin film transistors
Authors: Seo Soonjoo , Park Byoung-Nam , Evans Paul G.
Published: June 2006

We report ambipolar field-effect transistors fabricated from rubrene thin films on SiO2∕Si substrates. The mobilities of both holes and electrons were extremely low, ranging from 2.2×10−6to8.0×10−6cm2∕Vs, due to disorder in the films. Rubrene forms three-dimensional circular islands even at extremely low coverages and x-ray diffraction observations suggest that the film is amorphous. The formation of the conducting channel of the transistor follows the geometric percolation of rubrene islands.
Formation of oriented nanofibers using electrospinning
Authors: Kim GeunHyung , Kim WanDoo
Published: June 2006

This letter reports on a simple, easy method for generating suspended nanofibers on a dielectric substrate using various target electrodes. By controlling the electrostatic field between the target electrodes, the nanofibers can be oriented to the electric field direction at the electrodes. The alignment of nanofibers was dependent on the applied frequency, field strength, and shape of the electrode.
Static model for organic field-effect transistors including both gate-voltage-dependent mobility and depletion effect
Authors: Schliewe R. R. , Yildirim F. A. , von Emden W. , Witte R. , Bauhofer W. , Krautschneider W.
Published: June 2006

Physics-based models of organic field-effect transistors (OFETs) which can be used for computer-aided simulation of organic integrated circuits were investigated. For this purpose hybrid OFETs with poly(3-hexylthiophene-2,5-diyl) as the semiconductor were fabricated and characterized. The differential drain-source resistance reveals the need for a unified consideration of a gate-voltage-dependent mobility and of the depletion effect. We avoid neglecting the capacitance of the insulator and the semiconductor which would have otherwise introduced restrictions. The analytic modeling yields a compact static equivalent circuit diagram.
Single mode cw operation of 658nm AlGaInP lasers based on longitudinal photonic band gap crystal
Authors: Novikov I. I. , Karachinsky L. Ya. , Maximov M. V. , Shernyakov Yu. M. , Kuznetsov S. M. , Gordeev N. Yu. , Shchukin V. A. , Kop’ev P. S. , Ledentsov N. N. , Ben-Ami U. , Kalosha V. P. , Sharon A. , Kettler T. , Posilovic K. , Bimberg D. , Mikhelashvili V. , Eisenstein G.
Published: June 2006

GaInP–AlGaInP lasers with broad waveguide based on a longitudinal photonic band gap crystal have been studied. Lasers with 10μm stripe width exhibit single transverse mode operation. The vertical beam divergence is about 8° and is insensitive to the drive current. The aspect ratio is ∼2:1. The quality factor for the lateral beam M2 is less than 2 in single mode regime under pulsed excitation. The total maximum continuous wave output power in the single mode regime at 20°C is more than 115mW (for high reflection/antireflection facet coatings), indicating a dramatic reduction in the catastrophic optical mirror damage problem.
Crossover of magnetoresistance from negative to positive in the heterojunction composed of La0.82Ca0.18MnO3 and 0.5wt% Nb-doped SrTiO3
Authors: Zhou T. F. , Li G. , Wang N. Y. , Wang B. M. , Li X. G. , Chen Y.
Published: June 2006

We report the magnetotransport properties of the heterojunction composed of La0.82Ca0.18MnO3 (LCMO) and 0.5wt% Nb-doped SrTiO3 (SNTO). At temperature below 120K, the heterojunction only exhibits a negative magnetoresistance (MR) independent of bias current. At temperatures above 120K, with increasing bias current a crossover of MR from negative to positive is observed. This intriguing crossover of MR can be ascribed to the dominant spin character changing from the majority spin carriers to the minority spin carriers at the LCMO-SNTO interface due to their occupation in the complicated bands of La0.82Ca0.18MnO3.
Effect of electron beam treatment on adhesion of Ta/polymeric low-k interface
Authors: Gan Zhenghao , Chen Zhong , Mhaisalkar S. G. , Damayanti M. , Chen Zhe , Prasad K. , Zhang Sam , Ning Jiang
Published: June 2006

Reliability of the Cu/low-k structure is a serious concern since the metal/dielectric interface is generally weak. The adhesion of the Ta/polyarylene ether interfaces with and without electron beam (EB) treatment was investigated by four-point bending test, x-ray photoelectron spectroscopy, and density functional theory. Higher adhesion energy (Gc) was achieved with low-dose EB treatment, attributed to the strong Ta-arene interaction. However, high-dose EB breaks the aromatic rings partially, resulting in fewer available sites for Ta-arene bonding, leading to lower adhesion. It is suggested that the amount of carbon atoms involved in bonding with the metal is the key to improve the Ta/polymer adhesion.
Pulsed mode operation of strained microelectromechanical resonators in air
Authors: Cimalla V. , Foerster Ch. , Will F. , Tonisch K. , Brueckner K. , Stephan R. , Hein M. E. , Ambacher O. , Aperathitis E.
Published: June 2006

A pulsed mode magnetomotive operation of micro- and nanoelectromechanical devices in air is demonstrated, where viscous damping determines the quality factor of the device. An enhancement of the quality factor by increasing the resonant frequency using strained resonator structures is proposed. Internal strain is the result of the thermal mismatch between heteroepitaxial SiC or AlN layers and the silicon substrates. Comparing unstrained and strained resonators, an increase of the quality factor by one order of magnitude from about 30 to 300 was achieved. This increase will improve the sensing performance of such resonant structures for an operation in ambient environment.
Microscopic structures of MgO barrier layers in single-crystal Fe∕MgO∕Fe magnetic tunnel junctions showing giant tunneling magnetoresistance
Authors: Mizuguchi M. , Suzuki Y. , Nagahama T. , Yuasa S.
Published: June 2006

The microscopic structures of MgO(001) barrier layers in magnetic tunnel junctions showing giant tunneling magnetoresistance were characterized by in situ scanning tunneling microscopy. The MgO thin films formed exceedingly flat surfaces, and their terraces were made even flatter by annealing after deposition. This flattening of MgO surfaces apparently promotes coherent transport of electrons, which should enhance the tunneling magnetoresistance ratio. Local tunneling spectroscopy revealed that an annealed MgO layer has a critical thickness between 3 and 5 ML (monolayer), and a continuous film without pinholes can be formed over the thickness.
Trap levels in tris(8-hydroxyquinoline) aluminum studied by deep-level optical spectroscopy
Authors: Nakano Yoshitaka , Noda Koji , Fujikawa Hisayoshi , Morikawa Takeshi , Ohwaki Takeshi , Taga Yasunori
Published: June 2006

We have investigated band gap states in tris(8-hydroxyquinoline) aluminum on fabricated indium tin oxide∕Alq3∕LiF∕Al devices by using a deep-level optical spectroscopy (DLOS) technique. DLOS measurements after double-carrier injection into the Alq3 layer revealed a discrete trap level located at ∼1.39eV below the lowest unoccupied molecular orbital band. The pronounced 1.39eV level is attributable to an intrinsic nature of Alq3 and can be active as an efficient generation-recombination center that may impact the photophysical properties. Additionally, the effective band gap of the Alq3 layer became narrow from 3.05to2.80eV with increasing double-carrier injection rate.
An endogenous peptide signal in
Arabidopsis
activates components of the innate immune response
Authors: Huffaker Alisa , Pearce Gregory , Ryan Clarence A.
Published: June 2006

Innate immunity is initiated in animals and plants through the recognition of a variety of pathogen-associated molecules that in animals are called pathogen-associated molecular patterns and in plants are called elicitors. Some plant pathogen-derived elicitors have been identified as peptides, but peptide elicitors derived from the plant itself that activate defensive genes against pathogens have not been previously identified. Here, we report the isolation and characterization of a 23-aa peptide from
Arabidopsis
, called
At
Pep1, which activates transcription of the defensive gene
defensin
(
PDF1.2
) and activates the synthesis of H
2
O
2
, both being components of the innate immune response. The peptide is derived from a 92-aa precursor encoded within a small gene that is inducible by wounding, methyl jasmonate, and ethylene. Constitutive expression of the
At
Pep1 precursor gene
PROPEP1
in transgenic
Arabidopsis
plants causes a constitutive transcription of
PDF1.2
. When grown in soil, the transgenic plants exhibited an increased root development compared with WT plants and an enhanced resistance toward the root pathogen
Pythium irregulare
. Six paralogs of
PROPEP1
are present in
Arabidopsis
, and orthologs have been identified in species of several agriculturally important plant families, where they are of interest for their possible use in crop improvement.
Monte Carlo simulation of the new time-of-flight powder diffractometer EXED at the Hahn-Meitner-Institut
Authors: Lieutenant K. , Peters J. , Mezei F.
Published: June 2006

The new diffractometer EXED at HMI designed for high resolution and extreme environments (like very high magnetic fields) has been simulated in detail using the software package VITESS. The simulation includes the beam extraction system, beam splitter, kink, chopper system, sample and detector. Many parameters like coatings, kink angle, etc. were varied to improve the instrument. The chopper system was checked and a focussing guide optimized. Finally, powder diffraction patterns of an aluminium sample show that a resolution of Δd/d < 2 × 10−4 will be feasible at 176° detector angle. The data collection time is estimated on the basis of the simulation results for the flux at sample.
A Distributed Wireless Sensor Network for Radio Scene Analysis
Authors: Gandetto M. , Cattoni A. F. , Regazzoni Carlo S.
Published: June 2006

In this paper, a distributed approach to radio scene analysis is considered. A Wireless Sensor Network, composed by Software Defined and Cognitive terminals, is used to classify air interfaces present in the radio scene. Two modes, namely Frequency Hopping Code Division Multiple Access and Direct Sequence Code Division Multiple Access, are identified, employing a signal processing technique. Time Frequency analysis, and a distributed decision theory. Advantages given by distributed detection are used to improve the performance of a Mode Identification module. Results in terms of error probability are obtained by modelling the probability density function of considered features as Asymmetric Generalized and Generalized Gaussian functions.
Energy Restrained Data Dissemination in Wireless Sensor Networks
Authors: Kimura Naoto , Jolly Vasu , Latifi Shahram
Published: June 2006

Wireless sensor nodes can be mobile within a chosen area and communicate with neighboring nodes in the bounds of protocol limits. Since communications among all network components in sensor networks are wireless, a peer-to-peer protocol is employed between two nodes. Among many concerns about design of sensor networks are growing bandwidth demands, speed of information retrieval, and transporting bytes over the wireless networks to provide a quality service for the diverse requirements of the users, such as signal processing or multimedia applications. Although traditional routing protocols ignore power management issues for sensor networks, design and implementation of an efficient energy based routing is in the core interest. In this paper, we discuss the current power management protocols, and propose an energy restrained information dissemination scheme. Experimental analysis and comparison with related work show that using the proposed scheme we can save substantial energy as compared to the prior methods.
Protein disulfide isomerase–like proteins play opposing roles during retrotranslocation
Authors: Forster Michele L. , Sivick Kelsey , Park Young-nam , Arvan Peter , Lencer Wayne I. , Tsai Billy
Published: June 2006

Misfolded proteins in the endoplasmic reticulum (ER) are retained in the organelle or retrotranslocated to the cytosol for proteasomal degradation. ER chaperones that guide these opposing processes are largely unknown. We developed a semipermeabilized cell system to study the retrotranslocation of cholera toxin (CT), a toxic agent that crosses the ER membrane to reach the cytosol during intoxication. We found that protein disulfide isomerase (PDI) facilitates CT retrotranslocation, whereas ERp72, a PDI-like protein, mediates its ER retention. In vitro analysis revealed that PDI and ERp72 alter CT's conformation in a manner consistent with their roles in retrotranslocation and ER retention. Moreover, we found that PDI's and ERp72's opposing functions operate on endogenous ER misfolded proteins. Thus, our data identify PDI family proteins that play opposing roles in ER quality control and establish an assay to further delineate the mechanism of CT retrotranslocation.
Larval, prejuvenile and juvenile development of Eucinostomus currani
Authors: Jiménez‐Rosenberg S. P. A. , González‐Navarro E. A. , Saldierna‐Martínez R. J.
Published: June 2006

Larval and juvenile Eucinostomus currani are described based on pigmentation, meristics and morphometric characteristics of 198 specimens collected in Bahía de La Paz and Ensenada de La Paz, B.C.S., Mexico. Diagnostic characteristics are the presence of head melanophores and several punctuate melanophores scattered over the lateral surface of the gut from early stages, a tricolour pigment pattern forming on the dorsal fin in postflexion stage and black stripes on the flanks of prejuveniles and juveniles.
Critical periods in the life cycle and the effects of a severe spate vary markedly between four species of elmid beetles in a small stream
Authors: ELLIOTT J. M.
Published: June 2006

1. The chief objectives were: (i) to describe quantitatively the life cycles of four species of Elmidae,Elmis aenea,Esolus parallelepipedus,Oulimnius tuberculatusandLimnius volkmari; (ii) to use life tables to identify critical periods for survival in the life cycle of each species; (iii) to evaluate the immediate and longer‐term effects of a severe spate on densities of the four species. Monthly samples were taken over 63 months at two contrasting sites in a small stream: one in a deep section with macrophytes abundant, and the other in a shallow stony section.

2. There were five larval instars forO. tuberculatus, seven forL. volkmariand six for the other two species. The life cycle of each species took 1 year from egg hatching (chiefly in June forE. aeneaandO. tuberculatus, and July for the other species) to pupation in the stream bank and a further year before the adults in the stream matured and laid their eggs. Mature adults were present in most months, but were rare or absent in January and February and attained maximum densities in April forO. tuberculatusand May for the other species.

3. Laboratory experiments provided data on egg hatching and pupation periods and the number of eggs laid per female. Life tables compared maximum numbers per square metre for key life‐stages. Within each species, mortality rates between adjacent life‐stages were fairly constant among six cohorts and between sites, in spite of large differences in numbers. The only exception for all species was the high adult, but not larval, mortality during a severe spate.

4. Standardised life tables, starting with 1000 eggs, identified key life‐stages with the highest mortality, namely the early life‐stages forE. aenea(36% mortality), start of the overwintering period to pupation forO. tuberculatus(41%) andL. volkmari(51%), start of pupation to the maximum number of immature adults forE. parallelepipedus(41%) and between the maximum numbers of immature and mature adults forO. tuberculatus(41%). Therefore, critical periods for survival in the life cycle differed between species, presumably because of their different ecological requirements. Similarly, the effects of the spate on adult mortality, and hence egg production, varied between species, being most severe and long‐term forE. aeneaandO. tuberculatus, less severe forE. parallelepipedusand least severe with a rapid recovery forL. volkmari. Possible reasons for these discrepancies are discussed, but more data are required on the food and microhabitat requirements of the elmids before satisfactory explanations can be found.
Improving understanding and rigour through triangulation: an exemplar based on patient participation in interaction
Authors: Jones Aled , Bugge Carol
Published: June 2006

Aim. In this paper, we aim to explore the benefits of triangulation and to expose the positive contribution of using ‘triangulation for completeness’ within a study of a complex concept, namely patient participation during healthcare interaction.

Background. Complex concepts, such as patient participation, are often the focus of nursing research. Triangulation has been proposed as a technique for studying complexity but, although debates about triangulation are becoming more prevalent in the literature, there is little deliberation about the process through which triangulation for completeness, with its claims of forming more comprehensive and rigorous descriptions of concepts through use of multiple data sources, yields it purported benefits.

Methods. A seminar series, held between 2001 and 2003, brought together researchers actively involved in the study of patient participation in healthcare consultations. The group came from diverse methodological traditions and had undertaken research with a range of informants and a range of methods.

Discussion. The various studies used triangulation at different levels: within studies, across studies and across disciplines. Our examples support theoretical arguments that triangulation for completeness can lead to a more holistic understanding of a concept and can improve scientific rigour. Furthermore, we suggest that triangulation can improve research skills for individuals. Our examples suggest that the process through which understanding is enhanced is discursive and centres on discussions of convergent and unique findings; rigour is improved is through challenging findings, being encouraged to explain aspects of your research that may be taken for granted and improving transparency; and individual researcher's skills and abilities are improved is through a process of discussion and reflexivity.

Conclusions. Triangulation for completeness, on various levels, can improve the quality and utility of research about complex concepts through a range of discursive processes. Developing greater opportunity to collaborate at various levels of analysis could be an important development in nursing research.
Thermal conditioning of fifth‐instar Cydia pomonella (Lepidoptera: Tortricidae) affects HSP70 accumulation and insect mortality
Authors: YIN X. , WANG S. , TANG J. , HANSEN J. D. , LURIE S.
Published: June 2006

Abstract Levels of HSP70 protein of fifth‐instar codling moth [Cydia pomonella (L.) (Lepidoptera: Tortricidae)] are determined after conditioning at 35 °C for different times and also after recovery at 22 °C. Protein samples from larvae conditioned for different times are separated by sodium dodecyl sulphate‐polyacrylamide gel electrophoresis electrophoresis. Sub‐lethal thermal conditioning at 35 °C for 40 min, 2, 6 and 18 h induces new protein bands in the extracts from treated codling moth larvae. Immunodetection with an antibody to a heat‐inducible HSP70 indicates a stronger reaction after 35 °C for 2, 6 and 18 h than after 35 °C for 40 min or control and, during the recovery period at 22 °C, the level of heat shock protein decreases. Conditioning of fifth‐instar codling moths at 35 °C also induces thermotolerance in the insects and necessitates longer times at a lethal temperature to ensure mortality. Thermotolerance is correlated with the accumulation of heat inducible HSP70 protein.
Irradiance levels affect growth parameters and carotenoid pigments in kale and spinach grown in a controlled environment
Authors: Lefsrud Mark G. , Kopsell Dean A. , Kopsell David E. , Curran‐Celentano Joanne
Published: June 2006

Carotenoids play critical roles in both light harvesting and energy dissipation for the protection of photosynthetic structures. However, limited research is available on the impact of irradiance on the production of secondary plant compounds, such as carotenoid pigments. Kale (Brassica oleracea L.) and spinach (Spinacia oleracea L.) are two leafy vegetables high in lutein and β‐carotene carotenoids. The objectives of this study were to determine the effects of different irradiance levels on tissue biomass, elemental nutrient concentrations, and lutein β‐carotene and chlorophyll (chl) pigment accumulation in the leaves of kale and spinach. ‘Winterbor’ kale and ‘Melody’ spinach were grown in nutrient solution culture in growth chambers at average irradiance levels of 125, 200, 335, 460, and 620 μmol m−2 s−1. Highest tissue lutein β‐carotene and chls occurred at 335 μmol m−2 s−1 for kale, and 200 μmol m−2 s−1 for spinach. The accumulations of lutein and β‐carotene were significantly different among irradiance levels for kale, but were not significantly different for spinach. However, lutein and β‐carotene accumulation was significant for spinach when computed on a dry mass basis. Identifying effects of irradiance on carotenoid accumulation in kale and spinach is important information for growers producing these crops for dry capsule supplements and fresh markets.
Short‐term drought response of two white clover clones, sensitive and tolerant to O3
Authors: Bermejo Raúl , Irigoyen Juan José , Santamaría Jesús Miguel
Published: June 2006

In order to study observed differences in water status between Trifolium repens L. cv. Regal NC‐R and NC‐S biotypes, tolerant and sensitive to ozone, respectively, and trying to identify possible environmental strains for this widely used ozone biomonitoring system, the response of these two biotypes to a short‐term drought was evaluated. The evolution of both soil and plant water status along with leaf gas exchange parameters, leaf ascorbate peroxidase (EC 1.11.1.11), glutathione reductase (EC 1.8.1.7), superoxide dismutase (EC 1.15.1.11) enzymatic activities and leaf content in total soluble protein, total soluble sugars, proline for an equal number of clones of each biotype under drought and control treatments was registered for 5 days under greenhouse conditions and summer direct sunlight. The results obtained show that the water requirement of sensitive NC‐S clones is higher, as these tend to display higher values of leaf conductance and water use under optimal water availability. What is more, when the short‐term drought is imposed, symptoms of oxidative stress and a negative impact on most of the measured parameters are displayed at an earlier stage in this biotype, proving it to be more sensitive to low water availability. It is therefore suggested that these differences might be linked with the existing variability in ozone sensitivity between the biotypes and that at the same time, they could result in a poorer performance of this biomonitoring system in field assays under conditions of high evapotranspiratory demand, such as those registered during summer time in Southern Europe.