bluuebunny/crossref_metadata_2025 huggingface dataset:
BI-D1870 is a specific inhibitor of the p90 RSK (ribosomal S6 kinase) isoformsin vitroandin vivo
Authors: Sapkota Gopal P. , Cummings Lorna , Newell Felicity S. , Armstrong Christopher , Bain Jennifer , Frodin Morten , Grauert Matthias , Hoffmann Matthias , Schnapp Gisela , Steegmaier Martin , Cohen Philip , Alessi Dario R.
Published: December 2006

Hormones and growth factors induce the activation of a number of protein kinases that belong to the AGC subfamily, including isoforms of PKA, protein kinase B (also known as Akt), PKC, S6K p70 (ribosomal S6 kinase), RSK (p90 ribosomal S6 kinase) and MSK (mitogen- and stress-activated protein kinase), which then mediate many of the physiological processes that are regulated by these extracellular agonists. It can be difficult to assess the individual functions of each AGC kinase because their substrate specificities are similar. Here we describe the small molecule BI-D1870, which inhibits RSK1, RSK2, RSK3 and RSK4 in vitro with an IC50 of 10–30 nM, but does not signi-ficantly inhibit ten other AGC kinase members and over 40 other protein kinases tested at 100-fold higher concentrations. BI-D1870 is cell permeant and prevents the RSK-mediated phorbol ester- and EGF (epidermal growth factor)-induced phosphoryl-ation of glycogen synthase kinase-3β and LKB1 in human embry-onic kidney 293 cells and Rat-2 cells. In contrast, BI-D1870 does not affect the agonist-triggered phosphorylation of substrates for six other AGC kinases. Moreover, BI-D1870 does not suppress the phorbol ester- or EGF-induced phosphorylation of CREB (cAMP-response-element-binding protein), consistent with the genetic evidence indicating that MSK, and not RSK, isoforms mediate the mitogen-induced phosphorylation of this transcription factor.
Studies on the activity of the hypoxia-inducible-factor hydroxylases using an oxygen consumption assay
Authors: Ehrismann Dominic , Flashman Emily , Genn David N. , Mathioudakis Nicolas , Hewitson Kirsty S. , Ratcliffe Peter J. , Schofield Christopher J.
Published: December 2006

The activity and levels of the metazoan HIF (hypoxia-inducible factor) are regulated by its hydroxylation, catalysed by 2OG (2-oxoglutarate)- and Fe(II)-dependent dioxygenases. An oxygen consumption assay was developed and used to study the relationship between HIF hydroxylase activity and oxygen concentration for recombinant forms of two human HIF hydroxylases, PHD2 (prolyl hydroxylase domain-containing protein 2) and FIH (factor inhibiting HIF), and compared with two other 2OG-dependent dioxygenases. Although there are caveats on the absolute values, the apparent Km (oxygen) values for PHD2 and FIH were within the range observed for other 2OG oxygenases. Recombinant protein substrates were found to have lower apparent Km (oxygen) values compared with shorter synthetic peptides of HIF. The analyses also suggest that human PHD2 is selective for fragments of the C-terminal over the N-terminal oxygen-dependent degradation domain of HIF-1α. The present results, albeit obtained under non-physiological conditions, imply that the apparent Km (oxygen) values of the HIF hydroxylases enable them to act as oxygen sensors providing their in vivo capacity is appropriately matched to a hydroxylation-sensitive signalling pathway.
Effect of aging and obesity on the expression of dyslipidaemia in children from families with familial combined hyperlipidaemia
Authors: ter Avest Ewoud , Sniderman Allan D. , Bredie Sebastian J. H. , Wiegman Albert , Stalenhoef Anton F. H. , de Graaf Jacqueline
Published: December 2006

The aim of the present study was to delineate the mechanism(s) responsible for the increased secretion of VLDL (very-low-density lipoprotein) particles in patients with FCH (familial combined hyperlipidaemia). In 194 young adults (<25 years of age) recruited from families with FCH, we investigated how plasma lipids, (apo)lipoproteins and BMI (body mass index) varied with age. Furthermore, we performed a 5-year follow-up study of clinical and biochemical characteristics of a subset of this population (n=85) stratified by apoB (apolipoprotein B) levels (below or above the 75th percentile adjusted for age and gender). Plasma apoB concentration (r=0.45, P<0.0001), triacylglycerol (triglyceride) concentration (r=0.45, P<0.0001), LDL (low-density lipoprotein) subfraction profile (r=−0.46, P<0.0001) and BMI (r=0.51, P<0.0001) were significantly associated with age. Plasma apoB concentration in the hyperapoB group was already elevated at a young age, whereas other characteristics of FCH, as observed in adults, including triacylglycerol levels >1.5 mmol/l and/or small-dense LDL, were observed only sporadically. After the 5-year follow-up, BMI increased in both groups, and this increase was associated with changes in apoB (r=0.27, P<0.05), triacylglycerol (r=0.30, P<0.01), VLDL cholesterol (r=0.22, P<0.05), VLDL triacylglycerol (r=0.25, P<0.05) and high-density lipoprotein cholesterol (r=−0.27, P<0.05). In conclusion, we have found indirect evidence of a primary, presumably genetically determined, increase in plasma apoB concentration occurring early in life of offspring from families with FCH. However, aging-related post-maturation increases in adipose tissue mass also appear to contribute to an aggravation and/or modulation of this genetically determined apoB overproduction.
Calculation of the electric field in arrangements of intersecting spheres
Authors: Techaumnat B. , Takuma T.
Published: December 2006

The application of the method of images to the calculation of electric field in arrangements of intersecting conducting spheres is presented. The multipole re-expansions are utilized to determine the multipole images and the potential coefficients. The method is applicable for cases of electrically floating, grounded, or energized conducting spheres that intersect each other. Examples are given for two grounded intersecting spheres of equal radii and those of different radii, respectively, under an external uniform field. The results for the spheres of equal radii agree well with the analytical solutions for the case of completely overlapped spheres and touching spheres, respectively. For the spheres of different radii, the numerical results show that the method may also be used when the degree of intersection is not too high.
Constructal dendritic geometry and the existence of asymmetric bifurcation
Authors: Wechsatol W. , Ordonez J. C. , Kosaraju S.
Published: December 2006

This paper considers the fundamental question of whether the optimal geometry of dendritic tree networks is symmetric or asymmetric. Asymmetry of dendritic networks is a result of the relation between flow resistance and flow fraction at each bifurcation node. Asymmetry of bifurcation (asymmetry of Y-shaped assemblies) appears when the flow fraction at each bifurcation node is not equal to one-half. Asymmetric bifurcation provides lower flow resistance than symmetric bifurcation. Murray’s law of bifurcation (Di+1∕Di=2−1∕3) is valid only when the flow fraction at every bifurcation node in dendritic networks is one-half and the networks are symmetric. General rules to construct asymmetric trees are developed and reported in this paper. It is shown that even through pressure drops across round and square cross-sectional shape channels are different; their flow resistances can be expressed by similar relations.
Ultrasonic and spectroscopic studies on photoactivation of euglena
Authors: Saito Mitsunori , Morita Shin
Published: December 2006

We studied the effect of the irradiation wavelength on the activity of photosynthetic euglena. The ultrasonic manipulation technique was used for both the activity evaluation and the movement restriction in the spectral measurements. Euglenas that had been preserved in darkness became inactive, and accordingly most of them were trapped by the ultrasonic standing wave (0.8mW∕mm2). However, when they were exposed to light of 500 or 700nm wavelength (0.13W∕m2), they became active enough to escape from the trapping. By contrast, irradiation at 550, 600, or 650nm wavelength had no effect on their activity. Spectroscopic measurements, which used to be difficult for locomotive microorganisms, were conducted successfully by trapping euglena at a node of the ultrasonic standing wave. The absorption bands were observed at around 500 or 700nm, which corresponded to the irradiation wavelengths that activated euglena.
Inhomogeneous luminance in organic light emitting diodes related to electrode resistivity
Authors: Neyts Kristiaan , Marescaux Matthias , Nieto Angel Ullan , Elschner Andreas , Lövenich Wilfried , Fehse Karsten , Huang Qiang , Walzer Karsten , Leo Karl
Published: December 2006

In organic light emitting diodes (OLEDs) with transparent electrodes, the luminance usually becomes inhomogeneous if the size of the pixel increases above 10mm. A theoretical model for inhomogeneous voltage and luminance in OLEDs is provided together with an approximate analytical solution for the problem in case of cylindrical symmetry. Experimental observations of inhomogeneous luminance are compared with numerical simulations based on the theoretical model, proving the applicability of the approximations made in the theoretical model.
Uncertainty principle for Gabor systems and the Zak transform
Authors: Czaja Wojciech , Zienkiewicz Jacek
Published: December 2006

We show that if g∊L2(R) is a generator of a Gabor orthonormal basis with the lattice Z×Z, then its Zak transform Z(g) satisfies ∇Z(g)∉L2([0,1)2). This is a generalization and extension of the Balian-Low uncertainty principle.
Self-excitation of the plasma series resonance in radio-frequency discharges: An analytical description
Authors: Czarnetzki U. , Mussenbrock T. , Brinkmann R. P.
Published: December 2006

Self-excited plasma series resonances (PSR) are observed in capacitve discharges as high-frequency oscillations superimposed on the normal rf current. This high-frequency contribution to the current is generated by a series resonance between the capacitive sheath and the inductive and ohmic bulk of the plasma. The nonlinearity of the sheath leads to a complex dynamic. The effect is applied, e.g., as a diagnostic technique in commercial etch reactors where analysis is performed by a numerical model. Here a simple analytical investigation is introduced. In order to solve the nonlinear equations analytically, a series of approximation is necessary. Nevertheless, the basic physics is conserved and excellent agreement with numerical solutions is found. The model provides explicit and simple formula for the current waveform and the spectral range of the oscillations. In particular, the dependence on the discharge parameters is shown. Further, the model gives insight into an additional dissipation channel opened by the high-frequency oscillations. With decreasing pressure, the ohmic resistance of the bulk decreases as well, while the amplitude of the PSR oscillations grows. This results in substantially higher power dissipation that exceeds the contribution of classical stochastic heating.
Thermoacoustic waves near the liquid-vapor critical point
Authors: Carlès Pierre
Published: December 2006

The thermal relaxation in a fixed-volume cell of a near-critical fluid is governed by the rapid expansion of thermal boundary layers, which drive a series of thermoacoustic waves in the bulk fluid. The long-term cumulative effect of these waves is to increase the pressure in the cell, which in turn leads to a global temperature increase (a process called the “piston effect”). Recently, and for the first time, the thermoacoustic waves produced by the Piston Effect have been measured experimentally using interferometric methods [Y. Miura et al., Phys. Rev. E 74, 010101(R) (2006)]. In the present work, we use asymptotic methods in order to derive a complete theoretical model of the piston-effect-driven acoustic waves, applicable to real fluid equations of state and to arbitrary reduced temperatures. The predictions of this model are compared to the above-mentioned experimental data, and an excellent agreement is observed without any fitting parameter. This result confirms the high precision of the data in question and shows that asymptotic models such as ours can be a powerful tool for analyzing the results of such experiments.
Magnetic field generation by the Weibel instability at temperature gradients in collisionless plasmas
Authors: Fujita Yutaka , Kato Tsunehiko N. , Okabe Nobuhiro
Published: December 2006

The Weibel instability could be responsible for the generation of magnetic fields in various objects such as gamma-ray bursts, jets from active galactic nuclei, and clusters of galaxies. Using numerical simulations, the development of the Weibel instability at a temperature gradient is studied. It is found that current sheets are first generated at the gradient, and then they are rounded off and turn into current filaments. During this process, return currents are generated around the filaments and they prevent filaments from the merger. The magnetic fields around the filaments persist at least until t∼8000∕ωp, where ωp is the plasma frequency, and it is very likely that they survive for a much longer time.
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laser induced temperature profiles in n-GaAs: An analytical model probed with the Seebeck effect
Authors: Stiens J. , Vandermeiren W. , De Tandt C. , Vounckx R. , Shkerdin G. , Kotov V.
Published: December 2006

An analytic model describing the distribution of the electron temperature created by absorption of an optical beam with a cylindrical symmetry in a layered structure was developed. Main attention was paid to the contribution of the lattice heating in the stationary and nonstationary regimes. It was shown that both the spatial distribution of the incident stationary beam and the temporal distribution of the incident pulses can be retrieved from the spatial and temporal electron temperature dependences near the illuminated surface. Electron temperature distributions can be measured using the thermoelectric effect. Experimental results of the spatial and temporal measurements of the thermoelectric voltage were compared with the theoretical calculations and a satisfactory agreement between experimental and theoretical results was found near the incident beam center for the quasistationary regime. The experimentally derived Seebeck detector’s responsivity equals 17.5μV∕Wcm−2.
New multisymplectic self-adjoint scheme and its composition scheme for the time-domain Maxwell’s equations
Authors: Cai Jiaxiang , Wang Yushun , Wang Bin , Jiang Bin
Published: December 2006

In this paper, we investigate Euler-box scheme for Bridges’ multisymplectic form of Maxwell’s equations. A new multisymplectic scheme is derived for Maxwell’s equations. We prove that it is also a self-adjoint scheme in time direction. The multisymplecticity of composition schemes based on the new scheme is also discussed. Two numerical examples are proposed to indicate that the derived multisymplectic schemes are effective when used to integrate the 2+1 dimensional Maxwell’s equations.
Relationship between mechanical and magnetic properties in cold rolled low carbon steel
Authors: Takahashi S. , Kobayashi S. , Kikuchi H. , Kamada Y.
Published: December 2006

Structure-sensitive properties of minor hysteresis loops have been compared with Vickers hardness and ductile-brittle transition temperature (DBTT) obtained by Charpy impact test for cold rolled low carbon steel. Minor loops were measured with increasing magnetic field amplitude, step by step, and were analyzed in connection with the rolling reduction. We found that minor-loop coefficients deduced from relations between minor-loop parameters increase with increasing rolling reduction and have a simple relationship with both mechanical properties, Vickers hardness, and DBTT. We also found that these coefficients have a linear relation with coercive force obtained by the major loop. The present analysis method using minor loops is highly effective for nondestructive evaluation of ductile-brittle transition, in terms of the high sensitivity to lattice defects as well as low measurement field.
In situ investigation of the microstructure evolution in nanocrystalline copper electrodeposits at room temperature
Authors: Pantleon Karen , Somers Marcel A. J.
Published: December 2006

The microstructure evolution in copper electrodeposits at room temperature (self-annealing) was investigated by means of x-ray diffraction analysis and simultaneous measurements of the electrical resistivity as a function of time. In situ studies were started immediately after deposition of the various thick layers and continued with a unique time resolution until stabilization of the recorded data occurred. Independent of the copper layer thickness, the as-deposited microstructure consisted of nanocrystalline grains with orientation dependent crystallite sizes. Orientation dependent grain growth, crystallographic texture changes by multiple twinning, and a decrease of the electrical resistivity occurred as a function of time at room temperature. The kinetics of self-annealing is strongly affected by the layer thickness: the thinner the layer, the slower the microstructure evolution is, and self-annealing is suppressed completely for a thin layer with 0.4μm. The preferred crystallographic orientation of the as-deposited crystallites is suggested to cause the observed thickness dependence of the self-annealing kinetics.
Microstructural anisotropy at the ion-induced rippled amorphous-crystalline interface of silicon
Authors: Grigorian S. , Pietsch U. , Grenzer J. , Datta D. P. , Chini T. K. , Hazra S. , Sanyal M. K.
Published: December 2006

Using grazing-incidence x-ray scattering technique the authors have investigated the evolution of the damage profile of the transition layer between the ion-induced ripplelike pattern on top surface and the ripples at buried crystalline interface in silicon created after irradiation with 60keV Ar+ ions under 60°. The transition layer consists of a defect-rich crystalline part and a complete amorphous part. The crystalline regions are highly strained but relaxed for low dose and high dose irradiations, respectively. The appearance of texture in both cases shows that the damage of the initial crystalline structure by the ion bombardment takes place along particular crystallographic directions.
Coherent optical phonons in diamond
Authors: Ishioka Kunie , Hase Muneaki , Kitajima Masahiro , Petek Hrvoje
Published: December 2006

The authors report femtosecond dynamics of the coherent optical phonon of single crystal diamond. Sub-10fs, 395nm laser pulses excite 40THz coherent phonons with an extremely small damping rate (0.15ps−1). Linear power dependence of the phonon amplitude under off-resonant excitation condition gives a direct evidence for an eletric-field-driven generation mechanism. The coherent phonon generation is noticeably suppressed by doping with nitrogen impurities, in spite of their absorption in the near ultraviolet. The present study demonstrates that a simple pump-probe technique can be a powerful tool for evaluating the ultrafast coherent electronic and lattice dynamics of diamond materials.
Structural characteristics of GaSb∕GaAs nanowire heterostructures grown by metal-organic chemical vapor deposition
Authors: Guo Y. N. , Zou J. , Paladugu M. , Wang H. , Gao Q. , Tan H. H. , Jagadish C.
Published: December 2006

Highly lattice mismatched (7.8%) GaAs∕GaSb nanowire heterostructures were grown by metal-organic chemical vapor deposition and their detailed structural characteristics were determined by electron microscopy. The facts that (i) no defects have been found in GaSb and its interfaces with GaAs and (ii) the lattice mismatch between GaSb∕GaAs was fully relaxed suggest that the growth of GaSb nanowires is purely governed by the thermodynamics. The authors believe that the low growth rate of GaSb nanowires leads to the equilibrium growth.
Simultaneous determination of indium and nitrogen contents of InGaAsN quantum wells by optical in situ monitoring
Authors: Reentilä O. , Mattila M. , Sopanen M. , Lipsanen H.
Published: December 2006

In situ monitoring of metal-organic vapor phase epitaxial growth of InGaAsN∕GaAs multiquantum wells is studied. The complex refractive index of InGaAsN is determined for several indium and nitrogen contents based on the fits to the reflectance curve. Taking advantage of the different effects caused by the incorporation of indium and nitrogen on the complex refractive index of InGaAsN, the InGaAsN quantum well nitrogen and indium contents are simultaneously determined in situ.
Enhanced stability of the second order optical properties of high-Tg fluorinated electro-optic copolymer
Authors: Belardini A. , Dominici L. , Larciprete M. C. , Michelotti F. , Rousseau A. , Ratsimihety A.
Published: December 2006

In this work the authors investigated the second order nonlinear optical properties of a group of Disperse Red 1 based electro-optic fluorinated copolymers, synthesized with two fluorinated monomers: the α-fluoroacrylate monomer bearing an adamantane side group and the α-fluoroacrylate monomer bearing the Disperse Red 1 chromophore. By means of nonlinear ellipsometry at λ=1550nm, the poling induced electro-optic tensor main component r33 was determined. The polymer’s thermostability was investigated by means of the temperature scanning and isothermal relaxation techniques, leading to the determination of the depolarization temperature Tdep=136°C, corresponding to an activation energy for the relaxation of the orientational distribution of the active chromophores EA=105kcal∕mol. The increased thermostability of the copolymer, given by the adamantane side group, is then compared with that of other two groups of fluorinated copolymers.
Fabrication and magnetic properties of Fe∕Pt multilayered nanowires
Authors: Wang Huixin , Wu Yu Cheng , Zhang Lide , Hu Xiaoye
Published: December 2006

Fe ∕ Pt multilayered nanowires with well-defined interfaces and layer thicknesses were fabricated by a pulse-plating technique in nanoporous anodic alumina templates. The structure, surface morphology, and magnetic properties of the multilayered nanowire arrays have been characterized by x-ray diffractometer, field emission scanning electron microscope, transmission electron microscopy, and superconducting quantum interference device magnetometer. It is found that after being annealed at temperatures of 300°C, FePt ordered phase with high magnetic anisotropy is formed. This can be explained by rapid diffusion at Fe∕Pt interface.
Effect of high annealing temperature on giant tunnel magnetoresistance ratio of CoFeB∕MgO∕CoFeB magnetic tunnel junctions
Authors: Hayakawa J. , Ikeda S. , Lee Y. M. , Matsukura F. , Ohno H.
Published: December 2006

The authors report tunnel magnetoresistance (TMR) ratios as high as 472% at room temperature and 804% at 5K in pseudo-spin-valve (PSV) CoFeB∕MgO∕CoFeB magnetic tunnel junctions (MTJs) annealed at 450°C, which is approaching the theoretically predicted value. By contrast, the TMR ratios for exchange-biased (EB) SV MTJs with a MnIr antiferromagnetic layer are found to drop when they are annealed at 450°C. Energy dispersive x-ray analysis shows that annealing at 450°C induces interdiffusion of Mn and Ru atoms into the MgO barrier and ferromagnetic layers in EB-SV MTJs. Mechanisms behind the different annealing behaviors are discussed.
Investigation of capillary adhesion between the microcantilever and the substrate with electronic speckle pattern interferometry
Authors: Li Xide , Peng Yun
Published: December 2006

In this letter, the authors present an experimental study of the capillary adhesion of microcantilevers and substrate using electronic speckle pattern interferometry. The transient deformation of a microcantilever caused by the capillary force was measured and the energy function of the adhesion system was constructed based on the independent parameters of adhesion length and volume fraction of the adhesion medium. Therefore, the capillary force could be theoretically determined by the minimum energy function, and the deformation of the microcantilever at the equilibrium state could be calculated and compared with the experimental result.
Surface effects on the diffraction of plane compressional waves by a nanosized circular hole
Authors: Wang G. F. , Wang T. J. , Feng X. Q.
Published: December 2006

In the present letter, the authors consider the diffraction of plane harmonic compressional wave (P wave) by a nanosized circular hole. The surface elasticity theory is employed to incorporate the surface effects. The results show that once the radius of hole reduces to nanometers, surface energy significantly affects the diffraction of elastic waves. For incident waves with different frequencies, the influences of surface elasticity on dynamic stress concentration are discussed in details.
Low temperature chemical vapor deposition of Si-based compounds via SiH3SiH2SiH3: Metastable SiSn∕GeSn∕Si(100) heteroepitaxial structures
Authors: Tolle J. , Chizmeshya A. V. G. , Fang Y.-Y. , Kouvetakis J. , D’Costa V. R. , Hu C.-W. , Menéndez J. , Tsong I. S. T.
Published: December 2006

Growth of Si1−xSnx alloys on Ge1−ySny-buffered Si(100) was achieved via reactions of SnD4 and SiH3SiH2SiH3 at 275°C. Kinetic studies indicate that unprecedented low growth temperatures are made possible by the highly reactive SiH2 groups. The authors obtain supersaturated metastable compositions (y∼25%) near the indirect to direct band gap crossover predicted by first principles simulations. Extensive characterizations of composition, structure, and morphology show that the SiSn∕GeSn films grow lattice matched via a “compositional pinning” mechanism. The initial Raman observations of Si–Sn bond vibrations in a condensed phase are discussed in the context of simulated bond distributions in the alloys.
Haeckelites: A promising anode material for lithium batteries application. An ab initio and molecular dynamics theoretical study
Authors: Mpourmpakis Giannis , Froudakis George E. , Tylianakis Emmanuel
Published: December 2006

Using both ab initio and molecular dynamics calculations, the authors have investigated the lithium interaction with carbon nanotubes and the recently reported haeckelite nanotubes. Their results show that lithium metals interact preferably with the pentagonal and heptagonal rings of the haeckelite rather than the hexagonal of the carbon nanotube. The structural and electronic differences between the carbon and haeckelite nanotubes result in different binding energies of lithium metals. Thus, haeckelites are more promising materials for lithium storage applications than carbon nanotubes. They report that this carbon material can store Li metals with a density of LiC1.6.
Theoretical interpretation of Grimme’s spin-component-scaled second order Møller-Plesset theory
Authors: Szabados Ágnes
Published: December 2006

It is shown that spin-component-scaled second order Møller-Plesset theory proposed by Grimme [J. Chem. Phys. 118, 9095 (2003)] can be interpreted as a two-parameter scaling of the zero order Hamiltonian, a generalization of the approach reported by Feenberg [Phys. Rev. 103, 1116 (1956)].
Laser emission from dye-doped polymer film in opal photonic crystal cavity
Authors: Jin Feng , Li Chun-Fang , Dong Xian-Zi , Chen Wei-Qiang , Duan Xuan-Ming
Published: December 2006

The authors demonstrated the lasing emission of the cavity constructed by the allyl derivative of fluorescein doped dendrimer/polymer film and two opal photonic crystals. A dendrimer encapsulated the structure modified laser dye and increased its concentration up to 5.3wt% in the polymer film with high optical gain. Laser emission of the cavity was observed, which is located at 589nm with a full width at half maximum of 1.7nm above the lasing threshold of 15μJ∕pulse. The lasing output was observed at an unordinary angle owing to the superprism effect of opal photonic crystals.
Fuel loads, fire regimes, and post-fire fuel dynamics in Florida Keys pine forests
Authors: Sah Jay P. , Ross Michael S. , Snyder James R. , Koptur Suzanne , Cooley Hillary C.
Published: December 2006

In forests, the effects of different life forms on fire behavior may vary depending on their contributions to total fuel loads. We examined the distribution of fuel components before fire, their effects on fire behavior, and the effects of fire on subsequent fuel recovery in pine forests within the National Key Deer Refuge in the Florida Keys. We conducted a burning experiment in six blocks, within each of which we assigned 1-ha plots to three treatments: control, summer, and winter burn. Owing to logistical constraints, we burned only 11 plots, three in winter and eight in summer, over a 4-year period from 1998 to 2001. We used path analysis to model the effects of fuel type and char height, an indicator of fire intensity, on fuel consumption. Fire intensity increased with surface fuel loads, but was negatively related to the quantity of hardwood shrub fuels, probably because these fuels are associated with a moist microenvironment within hardwood patches, and therefore tend to resist fire. Winter fires were milder than summer fires, and were less effective at inhibiting shrub encroachment. A mixed seasonal approach is suggested for fire management, with burns applied opportunistically under a range of winter and summer conditions, but more frequently than that prevalent in the recent past.
Measurements of moisture in smoldering smoke and implications for fog
Authors: Achtemeier Gary L.
Published: December 2006

Smoke from wildland burning in association with fog has been implicated as a visibility hazard over roadways in the southern United States. A project began in 2002 to determine whether moisture released during the smoldering phases of southern prescribed burns could contribute to fog formation. Temperature and relative humidity measurements were taken from 27 smoldering ‘smokes’ during 2002 and 2003. These data were converted to a measure of the mass of water vapor present to the mass of dry air containing the vapor (smoke mixing ratio). Some smokes were dry with almost no moisture beyond ambient. Other smokes were moist with moisture excesses as large as 39 g kg–1. Calculations show that ground-level smoke moisture excesses have no impact on ambient relative humidity during the day. However, the impact at night can be large enough to increase the ambient relative humidity to 100%. Therefore smoke moisture may be a contributing factor to the location and timing of fog formation.
Soil heating and germination: investigations using leaf scorch on graminoids and experimental seed burial
Authors: Tozer Mark G. , Auld Tony D.
Published: December 2006

Burns conducted to reduce fuels are usually carried out under mild weather conditions. This introduces a risk that soil heating will be insufficient to trigger germination in species with a heat-shock requirement. Resprouting graminoids with leaves or culms arising from subterranean meristems can be used to estimate soil heating because the leaf is burnt to soil level and the subterranean tissue is killed to a depth dependent on the level of soil heating. Provided the meristem survives, the length of dead tissue is exposed following subsequent growth. We sought to determine whether the length of dead tissue (scorch length) was correlated with the post-fire recovery of Acacia suaveolens, a fire-sensitive shrub with seed germination dependent on heat shock. The peak emergence depth for this species varies as a function of soil heating: temperatures above 100°C induce seed death whereas temperatures below 60°C do not break dormancy. We found that average scorch length was correlated with average seedling emergence depth. However, experimental burial of scarified (i.e. non-dormant) seeds showed that the peak emergence depth was similar for seeds sown before, after or in the absence of fire. This suggests that post-germination mortality is also depth-dependent, with seedling survival reduced at depths from 0 to 20 mm. The results suggest that survival of seedlings will be enhanced if soil heating is sufficient to promote germination of seeds buried at least 20 mm deep. Scorch lengths on graminoid leaves provide an indication of whether this condition is met.
Direct evidence for a prefrontal contribution to the control of proactive interference in verbal working memory
Authors: Feredoes Eva , Tononi Giulio , Postle Bradley R.
Published: December 2006

Controlling the effects of proactive interference (PI), the deleterious effect of prior mental activity on current memory representations, is believed to be a key function of the prefrontal cortex. This view is supported by neuroimaging evidence for a correlation between the longer reaction times caused by high PI conditions of a working memory task and increased activity in left inferior frontal gyrus (IFG) of the prefrontal cortex. An alternative that has never been ruled out, however, is that this left IFG effect may merely reflect sensitivity to such nonspecific factors as difficulty and/or time on task. To resolve this confound, we applied the interference methodology of repetitive transcranial magnetic stimulation (rTMS) to the left IFG and two control regions while subjects performed delayed letter recognition. rTMS was guided with high-resolution magnetic resonance images and was time-locked to the onset of the memory probe. The effect of rTMS, a disruption of accuracy restricted to high-PI probes, was specific to the left IFG. These results demonstrate that unpredictable, phasic disruption of the left IFG selectively disrupts control of responses to high-conflict verbal working memory probes, and they conclusively reject nonspecific alternative accounts.
Muslim Brotherhood in Egypt & Sudan
Authors: Zahid Mohammed , Medley Michael
Published: December 2006

This article compares the evidence from two related movements: the contemporary Muslim Brotherhood in Egypt, and the cluster of organisations that have been closely associated with Hasan al-Turabi in Sudan, in order to query the extent to which Islamism is compatible with liberal democratic politics. The answers suggested are, in the Egyptian case, hopeful, but for Sudan decidedly pessimistic. However, there are complexities within both stories. The comparison indicates ways in which the outcomes are related to the framing circumstances, but also points out the limitations of the information currently available in the academic literature.
Improving motivation and goal setting for return to work in a population on sick leave: A controlled study
Authors: Drews Birgit , Nielsen Claus V. , Rasmussen Mette S. , Hjort Jakob , Bonde Jens P.
Published: December 2006

Aim: Limited knowledge precludes evidence-based interventions targeting return to work among employees on sick leave. The objective of this study was to examine the vocational effect of an intervention focused on motivation, goal setting, and planning of return to work. Design and methods: A total of 2,795 people, across 6 municipalities, on sick leave for at least 21 days received a questionnaire; 1,256 with a self-assessed poor prognosis for fast return to work were eligible for the study. An examination by a specialist in social medicine, followed by additional counselling by a social worker, was offered to 510 residents in two municipalities and accepted by 264 (52%). The goal was to enhance motivation, goal setting, and planning of return to work. Residents in the remaining municipalities (n=746) received the standard case management offered by the municipalities; 845 (67%) persons completed a follow-up questionnaire gathering data on general health and employment status. The duration of the sick leave was analysed by Cox regression, and the chance of being gainfully employed was analysed by logistic regression analysis, both adjusted for several covariates. Results: The intervention neither shortened sick leave periods nor increased the likelihood of gainful employment after one year (OR 0.76; 95% CI 0.45—1.28). Conclusions: A low-cost counselling programme addressing motivation, goal setting, and planning of return to work did not improve vocational outcomes or reduce the duration of sick leave.
Examining the ``Matthew Effect'' on the motivation and ability to make lifestyle changes in 217 heart rehabilitation patients
Authors: Mildestvedt Thomas , Meland Eivind
Published: December 2006

Aims: Those who are socioeconomically disadvantaged and people with emotional problems have a poorer prognosis for cardiovascular disease. The authors wanted to examine: (1) what effect household income, emotional status, high-risk smoking status, and severity of heart disease had on the ability of individuals to make dietary and exercise improvements after heart disease and (2) to what extent unfavourable lifestyle outcomes among disadvantaged people were mediated by motivational problems. Methods: A two-year follow-up study of the combined cohorts of a randomized controlled trial. Level of exercise and present dietary habits were measured at inclusion and after 6 and 24 months. Different motivational factors and emotional distress were measured during rehabilitation. Results: Autonomous self-regulation was lowest among smokers (b=-0.31, p=0.02) and female participants (b=0.39, p=0.004). Participants with high scores of emotional distress predicted lower motivation for all the measures. We found no association between socioeconomic status (household income) and the ability to perform lifestyle changes. Current smoking status predicted lower ability to obtain lifestyle changes on all measures. Emotional distress was related to lower ability to increase physical activity at 6 months' but not at 24 months' follow-up. The mediating effects of motivational factors were insignificant. Conclusions: The results of this study do not support the suspicion that preventive efforts accentuate the socioeconomic differences in cardiovascular health. Health-promotive efforts after heart disease should safeguard that high-risk groups such as smokers are not discouraged from improving their lifestyle in other areas.
Prevalence of Atopic Dermatitis Among Children Under 19 in an East‐Hungarian Agricultural County
Authors: Kuhnyar Agnes , Egyud Katalin , Szabo Imre , Hunyadi Janos , Kosa Lajos
Published: December 2006

The prevalence of atopic dermatitis has significantly increased in developed countries during the past several decades. Surveys performed in Hungary also show a growing number of atopic dermatitis (AD) cases, although, a carefully designed case‐controlled studies have not been performed. Therefore, we investigated the prevalence of AD in individuals under 19 years of age within the agricultural area of East‐Hungary. Combined data obtained with Schultz‐Larsen questionnaire on 1158 children were analyzed, and 25% of the index persons were examined by dermatologist. The mean prevalence of AD determined by questionnaires appeared to be 17.5% in the entire study population. Result of dermatological examination verified the validity and sensitivity of the questionnaire. A negative correlation was found between the severity of the disease and the length of breast feeding period. (Spearman′s correlation coefficient = − 0.2247, p = 0.034). The prevalence of AD in an East‐Hungarian agricultural area is nearly as high as that reported for populations residing in industrially developed countries, with a higher prevalence during childhood. Data suggest that premature abruption of breast feeding maybe one of the major factors among other environmental factors that is contributing to the development of AD.
Current Perspectives on Primary Immunodeficiency Diseases
Authors: Kumar Arvind , Teuber Suzanne S. , Gershwin M. Eric
Published: December 2006

Since the original description of X‐linked agammaglobulinemia in 1952, the number of independent primary immunodeficiency diseases (PIDs) has expanded to more than 100 entities. By definition, a PID is a genetically determined disorder resulting in enhanced susceptibility to infectious disease. Despite the heritable nature of these diseases, some PIDs are clinically manifested only after prerequisite environmental exposures but they often have associated malignant, allergic, or autoimmune manifestations. PIDs must be distinguished from secondary or acquired immunodeficiencies, which are far more common. In this review, we will place these immunodeficiencies in the context of both clinical and laboratory presentations as well as highlight the known genetic basis.
Cure of Chronic Viral Infection and Virus‐Induced Type 1 Diabetes by Neutralizing Antibodies
Authors: Ejrnaes Mette , von Herrath Matthias G. , Christen Urs
Published: December 2006

The use of neutralizing antibodies is one of the most successful methods to interfere with receptor‐ligand interactions in vivo. In particular blockade of soluble inflammatory mediators or their corresponding cellular receptors was proven an effective way to regulate inflammation and/or prevent its negative consequences. However, one problem that comes along with an effective neutralization of inflammatory mediators is the general systemic immunomodulatory effect. It is therefore important to design a treatment regimen in a way to strike at the right place and at the right time in order to achieve maximal effects with minimal duration of immunosuppression or hyperactivation. In this review we reflect on two examples of how short time administration of such neutralizing antibodies can block two distinct inflammatory consequences of viral infection. First, we review recent findings that blockade of IL‐10/IL‐10R interaction can resolve chronic viral infection and second, we reflect on how neutralization of the chemokine CXCL10 can abrogate virus‐induced type 1 diabetes.
Immunology and Genetic of Preeclampsia
Authors: Serrano Norma C.
Published: December 2006

Preeclampsia is a disease characterized by hypertension and proteinuria in the third trimester of pregnancy. Preeclampsia is a major cause of maternal mortality, and fetal death, especially in developing countries, but its aetiology remains unclear. Key findings support a causal role of superficial placentation driven by immune mal maladaptation, which then lead to reduced concentrations of angiogenic growth factors and to an increase in placental debris in the maternal circulation resulting in a maternal inflammatory response. Epidemiological research has consistently demonstrated a substantial familial predisposition to preeclampsia. Unfortunately, the conquest of the genes explaining such a individual susceptibility has been proved to be a hard task. However, genetics will also inform us about causality of environmental factors, and then serve as a tool to prioritize therapeutic targets for preventive strategies.
Towards a Vaccine Against Rheumatic Fever
Authors: Guilherme L. , Faé K. C. , Higa F. , Chaves L. , Oshiro S. E. , de Barros S. Freschi , Puschel C. , Juliano M. A. , Tanaka A. C. , Spina G. , Kalil J.
Published: December 2006

Rheumatic fever (RF) is an autoimmune disease which affects more than 20 million children in developing countries. It is triggered by Streptococcus pyogenes throat infection in untreated susceptible individuals. Carditis, the most serious manifestation of the disease, leads to severe and permanent valvular lesions, causing chronic rheumatic heart disease (RHD). We have been studying the mechanisms leading to pathological autoimmunity in RF/RHD for the last 15 years. Our studies allowed us a better understanding of the cellular and molecular pathogenesis of RHD, paving the way for the development of a safe vaccine for a post‐infection autoimmune disease. We have focused on the search for protective T and B cell epitopes by testing 620 human blood samples against overlapping peptides spanning 99 residues of the C‐terminal portion of the M protein, differing by one amino acid residue. We identified T and B cell epitopes with 22 and 25 amino acid residues, respectively. Although these epitopes were from different regions of the C‐terminal portion of the M protein, they showed an identical core of 16 amino acid residues. Antibodies against the B cell epitope inhibited bacterial invasion/adhesion in vitro. Our results strongly indicated that the selected T and B cell epitopes could potentially be protective against S. pyogenes.
Transcriptional Silencing of a Novel hTERT Reporter Locus during In Vitro Differentiation of Mouse Embryonic Stem Cells
Authors: Wang Shuwen , Hu Chunguang , Zhu Jiyue
Published: December 2006

The human telomerase reverse transcriptase hTERT is highly expressed in undifferentiated embryonic cells and silenced in the majority of somatic cells. To investigate the mechanisms of hTERT silencing, we have developed a novel reporter using a bacterial artificial chromosome (BAC) that contained the entire hTERT gene and its neighboring loci, hCRR9 and hXtrp2. Firefly and Renilla luciferases were used to monitor transcription from the hTERT and hCRR9 promoters, respectively. In mouse embryonic stem cells stably integrated with the BAC reporter, both hTERT and hCRR9 promoters were highly expressed. Upon differentiation into embryoid bodies and further into mineral-producing osteogenic cells, the hTERT promoter activity decreased progressively, whereas the hCRR9 promoter remained highly active, both resembling their endogenous counterparts. In fully differentiated cells, the hTERT promoter was completely silenced and adopted a chromatin structure that was similar to its native counterpart in human cells. Inhibition of histone deacetylases led to the opening of the hTERT promoter and partially relieved repression, suggesting that histone deacetylation was necessary but not sufficient for hTERT silencing. Thus, our result demonstrated that developmental silencing of the human TERT locus could be recapitulated in a chromosomal position-independent manner during the differentiation of mouse embryonic stem cells.
Markers improve clustering of CGH data
Authors: Liu Jun , Ranka Sanjay , Kahveci Tamer
Published: December 2006

Motivation: We consider the problem of clustering a population of Comparative Genomic Hybridization (CGH) data samples using similarity based clustering methods. A key requirement for clustering is to avoid using the noisy aberrations in the CGH samples.

Results: We develop a dynamic programming algorithm to identify a small set of important genomic intervals called markers. The advantage of using these markers is that the potentially noisy genomic intervals are excluded during the clustering process. We also develop two clustering strategies using these markers. The first one, prototype-based approach, maximizes the support for the markers. The second one, similarity-based approach, develops a new similarity measure called RSim and refines clusters with the aim of maximizing the RSim measure between the samples in the same cluster. Our results demonstrate that the markers we found represent the aberration patterns of cancer types well and they improve the quality of clustering significantly.

Availability: All software developed in this paper and all the datasets used are available from the authors upon request.

Contact: juliu@cise.ufl.edu