bluuebunny/crossref_metadata_2025 huggingface dataset:
Markers of Inflammation and Fat Distribution Following Weight Loss in African‐American and White Women
Authors: Fisher Gordon , Hyatt Tanya C. , Hunter Gary R. , Oster Robert A. , Desmond Renee A. , Gower Barbara A.
Published: April 2011

Changes in markers of inflammation (MOI) and fat distribution with weight loss between African‐American (AA) and white (W) women have yet to be characterized. The purpose of this study was to examine potential ethnic differences in MOI and regional fat distribution with weight loss, and identify the associations between these markers and changes in regional fat distribution with weight loss among AA and W women. Subjects were 126 healthy, premenopausal women, BMI 27–30 kg/m2. They were placed on a weight‐loss intervention consisting of diet and/or exercise until a BMI <25 was achieved. Fat distribution was measured with computed tomography, and body composition with dual‐energy X‐ray absorptiometry. Serum concentrations of tumor necrosis factor‐α (TNF‐α), soluble TNF receptor‐I (sTNFR‐I), sTNFR‐II, C‐reactive protein (CRP), and interleukin‐6 (IL‐6) were assessed. All MOI and adiposity measures significantly decreased with weight loss. Significant ethnic differences with weight loss were observed for fat mass, body fat, intra‐abdominal adipose tissue (IAAT), sTNFR‐I, and sTNFR‐II. Mixed‐model analysis indicated that adjusting for change in IAAT explained ethnic differences in change in TNF‐α and the decrease in TNF‐α with weight loss, while total fat mass only explained the decrease in sTNFR‐I and sTNFR‐II with weight loss. In conclusion, all MOI decreased following weight loss among W, whereas only IL‐6 and CRP decreased following weight loss in AA. The most distinct phenotypic difference observed was a greater impact of weight loss on TNF‐α in W compared to AA, which was directly associated with IAAT in W.
Elevated Serum 25(OH)D Concentrations, Vitamin D, and Calcium Intakes Are Associated With Reduced Adipocyte Size in Women
Authors: Caron‐Jobin Maude , Morisset Anne‐Sophie , Tremblay Angelo , Huot Céline , Légaré Denis , Tchernof André
Published: April 2011

Recent studies have suggested a beneficial effect of vitamin D and calcium on adipocyte metabolism and the metabolic profile. Our objective was to examine associations of vitamin D intake, calcium and dairy products as well as serum 25(OH)D concentration with adiposity measures and adipocyte size in women. Omental and subcutaneous adipose tissue samples were obtained from 43 women undergoing gynecological surgeries. Adipocyte size was measured using adipocyte suspensions from collagenase‐digested fat tissues. Total and visceral adiposity were assessed by dual‐energy X‐ray absorptiometry and computed tomography, respectively. Serum 25(OH)D was measured by radioimmmunoassay. Dietary intakes were assessed using a food frequency questionnaire. Women consuming two or more dairy product portions daily had smaller adipocytes in the omental depot compared to women consuming less than two portions daily (79 ± 12 vs. 94 ± 16 µm, P ≤ 0.01). Dietary intakes of calcium (r = −0.55) and vitamin D (r = −0.43) as well as serum 25(OH)D (r = −0.35) were also inversely and significantly associated with omental adipocyte size (P ≤ 0.05 for all). Dietary vitamin D intake was inversely associated with visceral adipose tissue area (r = −0.34, P ≤ 0.05). Serum 25(OH)D was also inversely associated with visceral adipose tissue area (r = −0.32) as well as with total adipose tissue area (r = −0.44), subcutaneous adipose tissue area (r = −0.36), BMI (r =−0.43) and total body fat mass (r = −0.41, P ≤ 0.05 for all). In conclusion, elevated dietary vitamin D intake and serum 25(OH)D values are related to lower visceral adiposity and omental adipocyte size in women.
Statistical optoacoustic image reconstruction using a-priori knowledge on the location of acoustic distortions
Authors: Deán-Ben X. Luís , Ntziachristos Vasilis , Razansky Daniel
Published: April 2011

Strong reflection and scattering effects, arising at the boundaries of acoustically mismatched areas in living organisms, such as bones, lungs, and other air cavities, may introduce severe image artifacts into optoacoustic reconstructions. Yet, in many cases, an a priori knowledge on the location of strongly mismatched areas is available, either based on general anatomical knowledge or using other imaging modalities. In this letter, we suggest a statistical optoacoustic image reconstruction method, which uses a priori knowledge on the location of acoustic distortions in order to improve image quality and quantification. Significant improvements are showcased experimentally on tissue mimicking phantoms of different complexities.
Numerical studies of ablated-plasma dynamics and precursor current of wire-array Z-pinches
Authors: Huang Jun , Sun Shun-Kai , Ding Ning , Ning Cheng , Xiao De-Long , Zhang Yang , Xue Chuang
Published: April 2011

The dynamics of ablated plasmas of wire-array Z-pinches are studied numerically in (r,θ) geometry by using the magnetohydrodynamic (MHD) simulation model in which the mass injection boundary conditions are presented, and two-dimensional spatio-temporal distributions of magnetic field and precursor current during the ablation phase are obtained. The ablated-plasma dynamics contains four processes: drifting toward the axis, arriving at the axis and forming the precursor column, and contraction and expansion of the precursor column. The relationship among the maximum inward velocity of ablated plasma streams and the initial wire array parameters is analyzed and it is found that this velocity is relatively sensitive to the change of inter-wire separation but weakly depends on the original array radius. The results are in reasonable agreement with the experiments on MAGPIE facility. The origin of the current flow in the precursor plasmas is analyzed from the point of view of the B-field convection in (r,θ) plane. The dynamics of ablation streams determine the distribution of magnetic field and the current density Jz inside the wire array. The precursor current can be approximately calculated by the integral of Jz inside the region of a radius near to the column. In this model, the fraction of precursor current is less than 10% of the total current, which is close to the experimental results. When the current waveform is fixed, the increase of the inter-wire gap or decrease of the initial radius will lead to the increase of the precursor current.
Modulational instability and nonlinear evolution of two-dimensional electrostatic wave packets in ultra-relativistic degenerate dense plasmas
Authors: Misra Amar Prasad , Shukla Padma Kant
Published: April 2011

We consider the nonlinear propagation of electrostatic wave packets in an ultra-relativistic (UR) degenerate dense electron–ion plasma, whose dynamics is governed by the nonlocal two-dimensional nonlinear Schrödinger-like equations. The coupled set of equations is then used to study the modulational instability (MI) of a uniform wave train to an infinitesimal perturbation of multidimensional form. The condition for the MI is obtained, and it is shown that the nondimensional parameter, β∝λCn01/3 (where λC is the reduced Compton wavelength and n0 is the particle number density) associated with the UR pressure of degenerate electrons, shifts the stable (unstable) regions at n0~1030cm-3 to unstable (stable) ones at higher densities, i.e., n0>̃7×1033. It is also found that the higher the values of n0, the lower is the growth rate of MI with cut-offs at lower wave numbers of modulation. Furthermore, the dynamical evolution of the wave packets is studied numerically. We show that either they disperse away or they blowup in a finite time, when the wave action is below or above the threshold. The results could be useful for understanding the properties of modulated wave packets and their multidimensional evolution in UR degenerate dense plasmas, such as those in the interior of white dwarfs and/or pre-Supernova stars.
Three-dimensional mapping of nickel oxidation states using full field x-ray absorption near edge structure nanotomography
Authors: Nelson George J. , Harris William M. , Izzo John R. , Grew Kyle N. , Chiu Wilson K. S. , Chu Yong S. , Yi Jaemock , Andrews Joy C. , Liu Yijin , Pianetta Piero
Published: April 2011

The reduction-oxidation cycling of the nickel-based oxides in composite solid oxide fuel cells and battery electrodes is directly related to cell performance. A greater understanding of nickel redox mechanisms at the microstructural level can be achieved in part using transmission x-ray microscopy (TXM) to explore material oxidation states. X-ray nanotomography combined with x-ray absorption near edge structure (XANES) spectroscopy has been applied to study samples containing distinct regions of nickel and nickel oxide (NiO) compositions. Digitally processed images obtained using TXM demonstrate the three-dimensional chemical mapping and microstructural distribution capabilities of full-field XANES nanotomography.
Two dimensional cylindrical fast magnetoacoustic solitary waves in a dust plasma
Authors: Liu Hai-Feng , Wang Shi-Qing , Wang Zhan-He , Li Chang-Zheng , Yao Liu , Yang Fa-Zhan
Published: April 2011

The nonlinear fast magnetoacoustic solitary waves in a dust plasma with the combined effects of bounded cylindrical geometry and transverse perturbation are investigated in a new equation. In this regard, cylindrical Kadomtsev–Petviashvili (CKP) equation is derived using the small amplitude perturbation expansion method. Under a suitable coordinate transformation, the CKP equation can be solved analytically. It is shown that the dust cylindrical fast magnetoacoustic solitary waves can exist in the CKP equation. The present investigation may have relevance in the study of nonlinear electromagnetic soliton waves both in laboratory and astrophysical plasmas.
Negative differential velocity in ultradilute GaAs1−xNx alloys
Authors: Vogiatzis N. , Rorison J. M.
Published: April 2011

We present theoretical results on steady state characteristics in bulk GaAs1−xNx alloys (x ≤ 0.2) using the single electron Monte-Carlo method. Two approaches have been used; the first assumes a GaAs band with a strong nitrogen scattering resonance and the second uses the band anti-crossing model, in which the localized N level interacts with the GaAs band strongly perturbing the conduction band. In the first model we observe two negative differential velocity peaks, the lower one associated with nitrogen scattering while the higher one with polar optical phonon emission accounting for the nonparabolicity effect. In the second model one negative differential velocity peak is observed associated with polar optical phonon emission. Good agreement with experimental low field mobility is obtained from the first model. We also comment on the results from both Models when the intervalley Г → L transfer is accounted for.
Controlling the betatron oscillations of a wakefield-accelerated electron beam by temporally asymmetric laser pulses
Authors: Nam Inhyuk , Hur Min Sup , Uhm Han Sup , Hafz Nasr A. M. , Suk Hyyong
Published: April 2011

Based on two-dimensional particle-in-cell simulations, we investigated the electron beam’s transverse oscillations by temporally asymmetric laser pulses in laser wakefield acceleration. Of particular interest in this article are the effects of ultrashort laser pulses having sharp rising and slow falling time scales. In this situation, the accelerated electron beam interacts directly with the laser field and undergoes transverse oscillations due to a phase-slip with the laser field. This oscillation can be matched with the betatron oscillation due to the focusing force of the ions, which can lead to a large transverse oscillation amplitude due to the resonance between them. Furthermore, in this case, the electron beam can be microbunched at the laser wavelength, which may provide the possibility for generation of a coherent synchrotron radiation.
Interaction of Cu and plastic plasmas as a method of forming laser produced Cu plasma streams with a narrow jet or pipe geometry
Authors: Kasperczuk A. , Pisarczyk T. , Chodukowski T. , Kalinowska Z. , Parys P. , Ullschmied J. , Krousky E. , Pfeifer M. , Skala J. , Klir D. , Kravarik J. , Kubes P. , Rezac K. , Pisarczyk P.
Published: April 2011

This brief communication is aimed at investigations of interaction of axially symmetrical light (plastic) plasma with heavy (copper) plasma. The use of axially symmetrical target compositions consisting of materials with low and high atomic numbers makes it possible to create different plasma stream configurations (e.g., very narrow jet or pipe). In the paper certain their applications are suggested.
Large acoustic solitons and double layers in plasmas with two positive ion species
Authors: Verheest Frank , Hellberg Manfred A. , Saini Nareshpal Singh , Kourakis Ioannis
Published: April 2011

Large nonlinear acoustic waves are discussed in a plasma made up of cold supersonic and adiabatic subsonic positive ions, in the presence of hot isothermal electrons, with the help of Sagdeev pseudopotential theory. In this model, no solitons are found at the acoustic speed, and no compositional parameter ranges exist where solutions of opposite polarities can coexist. All nonlinear modes are thus super-acoustic, but polarity changes are possible. The upper limits on admissible structure velocities come from different physical arguments, in a strict order when the fractional cool ion density is increased: infinite cold ion compression, warm ion sonic point, positive double layers, negative double layers, and finally, positive double layers again. However, not all ranges exist for all mass and temperature ratios. Whereas the cold and warm ion sonic point limitations are always present over a wide range of mass and temperature ratios, and thus positive polarity solutions can easily be obtained, double layers have a more restricted existence range, specially if polarity changes are sought.
Nanoscale silicon-on-insulator deformation induced by stressed liner structures
Authors: Murray Conal E. , Ying A. , Polvino S. M. , Noyan I. C. , Holt M. , Maser J.
Published: April 2011

Rotation and strain fields were mapped across silicon-on-insulator (SOI) regions induced by overlying stressed Si3N4 features using x-ray nanobeam diffraction. The distribution in SOI tilt exhibited an antisymmetric distribution with a maximum magnitude of 7.9 milliradians, representing one of the first direct measurements of the lattice tilt conducted in situ within buried layers using a spot size of less than 100 nm. The measured rotation distribution corresponds to simulated values generated by boundary element method modeling, indicating that the strain transfer into the underlying SOI primarily induces elastic deformation.
The Bañados, Teitelboim, and Zanelli spacetime as an algebraic embedding
Authors: Willison Steven
Published: April 2011

A simple algebraic global isometric embedding is presented for the nonrotating Bañados, Teitelboim, and Zanelli black hole and its counterpart of Euclidean signature. The image of the embedding, in Minkowski space of two extra dimensions, is the intersection of two quadric hypersurfaces. Furthermore an embedding into AdS4 or H4 is also obtained, showing that the spacetime is of embedding class one with respect to maximally symmetric space of negative curvature. The rotating solution of Euclidean signature is also shown to admit a quadratic algebraic embedding, but seemingly requires more than two extra dimensions.
Erratum: “New trace formulae for a quadratic pencil of the Schrödinger operator” [J. Math. Phys. 51, 033506 (2010)]
Authors: Yang Chuan Fu
Published: April 2011

In this note we correct a mistake made in my paper [J. Math. Phys. 51, 033506 (2010)]. Using the contour integration method we shall obtain a new regularized trace formula for Schrödinger operator with energy-dependent potential.
Tensile fracture criterion of metallic glass
Authors: Qu R. T. , Eckert J. , Zhang Z. F.
Published: April 2011

The fracture criterion of metallic glass (MG) is still under debate so far. On the issue of describing the normal stress effect on the tensile fracture behaviors of MGs, there are two fracture criteria: the Mohr-Coulomb (M-C) criterion and the Ellipse criterion. In this study, the normal stress acting on the tensile fracture planes was controlled and varied in a wide range by introducing inclined notches with different inclination angles to a series of Zr-based MG specimens. Based on the experimental results, both the Ellipse criterion and the M-C criterion are compared and analyzed. The experimental results reveal that the Ellipse criterion gives a better prediction than the M-C criterion for the tensile fracture behavior of the investigated Zr-based MG in a wide normal stress range. Moreover, the pressure and normal stress effects were separately considered and some other criteria were further discussed. It is found that under tensile loading, the pressure effect is weak while the normal stress effect is strong. Combined with previously reported results for a variety of MGs, the Ellipse criterion is found to have the capability to describe all the different contributions of the normal stress effect and thus may be suitable as a unified tensile fracture criterion for all MGs with different fracture behaviors.
Friedel oscillation effects on the elastic collision in degenerate quantum collisional plasmas
Authors: Ki Dae-Han , Jung Young-Dae
Published: April 2011

The Friedel oscillation effects on the elastic electron–ion collisions are investigated in degenerate quantum collisional plasmas. The eikonal analysis and effective interaction model including the far-field terms caused by the quantum screening and Kohn singularities are employed to obtain the eikonal scattering phase shift and eikonal cross section as functions of the collision energy, impact parameter, collision frequency, Fermi wave number, and collision energy. The results show that the amplitude of the eikonal phase shift decreases with an increase of the collision frequency. It is found that the Friedel oscillation causes the oscillatory behavior of the differential cross section in the small-frequency domain. It is also found that the quantum oscillating behavior suddenly vanishes with an increase of the collision frequency. In addition, the collision effect of the differential cross section decreases with increasing impact parameter. It is also found that the oscillating amplitude of the differential cross section decreases with an increase of the Fermi wave number.
Heating of solar chromosphere by electromagnetic wave absorption in a plasma slab model
Authors: Tsiklauri D. , Pechhacker R.
Published: April 2011

The heating of solar chromospheric internetwork regions by means of the absorption of electromagnetic (EM) waves that originate from the photospheric blackbody radiation is studied in the framework of a plasma slab model. The absorption is provided by the electron-neutral collisions in which electrons oscillate in the EM wave field and electron-neutral collisions damp the EM wave. Given the uncertain nature of the collision cross-section due to the plasma microturbulence, it is shown that for plausible physical parameters, the heating flux produced by the absorption of EM waves in the chromosphere is between 20% and 45% of the chromospheric radiative loss flux requirement. It is also established that there is an optimal value for the collision cross-section, 5×10-18 m2, which produces the maximal heating flux of 1990 W m−2.
Two dielectric relaxation mechanisms observed in lanthanum doped barium strontium titanate glass ceramics
Authors: Zhang Yong , Ma Tao , Wang Xiangrong , Yuan Zongbao , Zhang Qian
Published: April 2011

The dielectric relaxation at temperatures ranging from 100 °C to 550 °C in lanthanum-doped barium strontium titanate glass ceramics has been investigated by measurements of both dielectric temperature curve and complex impedance spectroscopy. The temperature dependence of dielectric properties reveals two regimes. In the first regime, at temperatures lower than 350 °C, the charge carrier contributed to interfacial polarization is conduction electrons. In contrast, in the second regime, at temperatures higher than 350 °C, the dielectric relaxation was attributed to the thermally activated movement of oxygen vacancies. Thus, two relaxation mechanisms could be explained on the basis of defect chemistry and impedance analysis.
Intrinsic and doped coupled quantum dots created by local modulation of implantation in a silicon nanowire
Authors: Pierre M. , Roche B. , Wacquez R. , Jehl X. , Sanquer M. , Vinet M.
Published: April 2011

We present a systematic study of various ways (top gates, local doping, substrate bias) to fabricate and tune multi-dot structures in silicon nanowire multigate metal-oxide-semiconductor field-effect transistors. The carrier concentration profile of the silicon nanowire is a key parameter to control the formation of tunnel barriers and single-electron islands. It is determined both by the doping profile of the nanowire and by the voltages applied to the top gates and to the substrate. Local doping is achieved with the realization of up to two arsenic implantation steps in combination with gates and nitride spacers acting as a mask. We compare nominally identical devices with different implantations and different voltages applied to the substrate, leading to the realization of both intrinsic and doped coupled dot structures. We demonstrate devices in which all the tunnel resistances toward the electrodes and between the dots can be independently tuned with the control top gates wrapping the silicon nanowire.
Experimental and theoretical study for InAs quantum dashes-in-a-step-well structure on (001)-oriented InP substrate
Authors: Kong J. X. , Zhu Q. S. , Xu B. , Wang Z. G.
Published: April 2011

An InAs/In0.73Ga0.27As/In0.53Ga0.47As/In0.53Al0.235Ga0.235As quantum dashes-in-a-step-well (QDSWELL) structure grown via molecular beam epitaxy has been studied. It is observed that the photoluminescence (PL) emission wavelength of such a structure can be as long as 2.12 μm at room temperature (RT). This is the longest emission wavelength of InAs QDashes to be realized at RT. The electron and hole energy levels of the InAs/In0.73Ga0.27As/In0.53Ga0.47As/In0.53Al0.235Ga0.235As QDSWELL structure have been calculated using effective-mass envelope-function theory. The calculated transition energy EE1-HH1 (from the first electron energy level E1 to the first heavy-hole energy level HH1) agrees with the measured PL emission peak position quite well. It is found that QDSWELL is an alternative structure for realizing lasers with wavelengths beyond 2 μm at RT.
Focusing of the lowest antisymmetric Lamb wave in a gradient-index phononic crystal plate
Authors: Wu Tsung-Tsong , Chen Yan-Ting , Sun Jia-Hong , Lin Sz-Chin Steven , Huang Tony Jun
Published: April 2011

In this letter, we numerically demonstrate focusing of the lowest antisymmetric Lamb wave in a gradient-index phononic crystal (PC) silicon plate and its application as a beam-width compressor for compressing Lamb wave into a stubbed phononic tungsten/silicon plate waveguide. The results show that beam width of the lowest antisymmetric Lamb wave in the PC thin plate can be compressed efficiently and fitted into tungsten/silicon PC plate waveguide over a wide range of frequency.
Self-assembled ordered arrays of nanoscale germanium Esaki tunnel diodes
Authors: Zhu Kaigui , Wang Wu , Shao Qingyi , Zhao Dongning , Lu Yongfeng , Ianno Natale
Published: April 2011

We have self-assembled regimented arrays of vertical ∼100 nm diameter Ge Esaki tunnel diodes using nanosphere lithography. Measurements of the current-voltage characteristics of individual nanodiodes using conductive atomic force microscopy at room temperature reveal pronounced negative differential resistance under forward bias, with a peak to valley ratio of 2–4. These diode arrays could constitute a neuromorphic circuit architecture exhibiting collective computational activity.
Resistance switching and white-light photovoltaic effects in BiFeO3/Nb–SrTiO3 heterojunctions
Authors: Qu T. L. , Zhao Y. G. , Xie D. , Shi J. P. , Chen Q. P. , Ren T. L.
Published: April 2011

BiFeO 3 / Nb – SrTiO 3 heterojunctions with room-temperature resistance switching (RS) and white-light photovoltaic (PV) effects were fabricated by pulsed laser deposition. The current-voltage characteristics of these heterojunctions show a good rectifying property with a large rectifying ratio of 104. Nonvolatile bipolar RS effect was observed with an ON/OFF-state current ratio of about 102. The heterojunctions also exhibit a substantial white-light PV effect. Both the RS and PV behaviors can be modulated by additional pulsed voltages, which control the electric polarization of the heterojunctions. This letter is helpful for exploring the multifunctional heterojunctions and their applications in memory devices and solar cells.
Enhancement of nonreciprocal phase shift by magneto-optical slot waveguide with a compensation wall
Authors: Zhang Wenfu , Mu Jian-Wei , Huang Wei-Ping , Zhao Wei
Published: April 2011

We demonstrated that the nonreciprocal phase shift (NPS) can be efficiently enhanced by introducing a low-index magneto-optical (MO) slot with a compensation wall (CW) in a high-index non-MO waveguide. The proposed structure has been examined by a perturbation theory and it is found that by adjusting the slot width and waveguide height, more than 20 times enhancement of NPS comparing with the rib waveguide with a CW can be realized.
Note: Design and characterization of an optical light source based on mixture of white and near-ultraviolet light emitting diode spectra
Authors: Sametoglu Ferhat , Celikel Oguz
Published: April 2011

An optical light source based on a solid-state lighting technology is designed. Main components of the light source are a phosphor-converted white and a near-ultraviolet (near-UV) light emitting diodes (LEDs), the spectral power distributions (SPDs) of which are mixed using a fiber optic combiner. The near-UV LED is used for improving insufficient SPDs of the white LED at shorter wavelengths of the visible radiation. Stable direct current power supplies are also designed and used to operate each of the LED separately. Three steps of the driving current can be selected by means of serial resistors altered with a commutator at nominal current values of ∼40%, ∼50%, and ∼69%. The light source can be used for many characteristic measurements within the scope of photometry and colorimetry.
High speed nano-metrology
Authors: Humphris Andrew D. L. , Zhao Bin , Catto David , Howard-Knight Jeremy P. , Kohli Priyanka , Hobbs Jamie K.
Published: April 2011

For manufacturing at the nanometre scale a method for rapid and accurate measurement of the resultant functional devices is required. Although atomic force microscopy (AFM) has the requisite spatial resolution, it is severely limited in scan speed, the resolution and repeatability of vertical and lateral measurements being degraded when speed is increased. Here we present a new approach to AFM that makes a direct and feedback-independent measurement of surface height using a laser interferometer focused onto the back of the AFM tip. Combining this direct height measurement with a passive, feedback-free method for maintaining tip-sample contact removes the constraint on scan speed that comes from the bandwidth of the z-feedback loop. Conventional laser reflection detection is used for feedback control, which now plays the role of minimising tip-sample forces, rather than producing the sample topography. Using the system in conjunction with a rapid scanner, true height images are obtained with areas up to (36 × 36) μm2 at 1 image/second, suitable for in-line applications.
Partitioning spatial and temporal variability of tropical near-shore macrobenthic assemblages affected by natural and anthropogenic disturbances
Authors: Rodríguez-Pliego P. , Hernández-Arana H. A. , Ardisson P.-L.
Published: April 2011

Coastal zones throughout the world are subject to natural and anthropogenic disturbances that modify the natural assemblages. The present study determined the response of the assemblage of macrobenthic invertebrates to the presence of a pier and natural climatic variations. Two analytical models were considered; one was an asymmetric model that permitted the comparison of the sector closest to the pier (impact) with the average of the sectors located further away (controls); the other was a three-way model that enabled the three sectors within the area to be analysed. With both models, the differences were compared among the sampling periods and the scale at which the variation in the data was greatest. No differences were detected among individual sectors or between the control and impact sectors. However, significant differences were found among the four periods. The zone closest to the pier presented greater temporal variability. This relationship suggests that the pier affecting the assemblage and the impact may be increased by the climatic conditions prevalent in the zone. It is necessary to establish a broader temporal analysis and a more detailed analysis of the structure and composition of the benthic assemblage to elucidate this temporal and spatial variability.
The removal of colloidal lead during estuarine mixing: seasonal variations and importance of iron oxides and humic substances
Authors: Tanguy Virginie , Waeles Matthieu , Gigault Julien , Cabon Jean-Yves , Quentel François , Riso Ricardo D.
Published: April 2011

In the present study, seven colloidal fractions of lead (Pb) were analysed along the mixing zone of the Penzé estuary over the Year 2009, with the aim to provide some insight into the mechanism that removes the metal from the <0.45-µm fraction. According to our results, Pb was generally found as large colloids (>300 kDa) and was removed in the salinity range 0–10 from all of the size fractions where it was significantly found. Because the colloidal fractionation of Pb was strongly linked to that of iron (Fe) and humic substances (HS), the removal of Pb in the mixing area must occur under flocculation of organomineral complexes. A key period corresponding to the first strong autumnal precipitations was also revealed in the present work. At this time of the year, the mobilisation of Pb (and Fe) from catchment soils is enhanced by the mobilisation of HS and the metal is associated with smaller colloids (30–300 kDa).
Comparing food-web impacts of a native invertebrate and an invasive fish as predators in small floodplain wetlands
Authors: Ho Susie S. , Bond Nick R. , Lake P. Sam
Published: April 2011

Gambusia holbrooki is an invasive predatory poeciliid fish in wetlands of south-eastern Australia, where it coexists with the native waterbug Anisops thienemanni (Notonectidae). Gambusia has been shown to produce trophic cascades, leading to increased algal biomass following invasion, whereas these effects relative to the often-dominant invertebrate predator Anisops are unknown. Given its flexible diet, we predicted that Gambusia would feed more broadly than Anisops, thereby reducing the abundance of zooplankton grazers, and increasing chlorophyll a. We tested this hypothesis in experimental 110-L wetland mesocosms, using Gambusia and Anisops alone and in combination, in addition to no-predator treatments. We ran two experiments lasting 91 and 35 days, respectively. Both fish and macroinvertebrates generated weak trophic cascades, resulting in minor increases in chlorophyll a above concentrations in control treatments. Gambusia, in lowering total zooplankton abundances, triggered a larger, although still relatively small, algal response relative to Anisops. Impacts of both predators on dominant invertebrate grazers (e.g. Simocephalus spp., copepod nauplii) were similar, although Anisops was associated with an increase in ostracod (Newnhamia sp.) numbers. The similar trophic role of the two predators on algae was unexpected, given their different effects on planktonic communities and their very different taxonomic positions and zoogeographic origins.
Ecological roles of the parasitic phytomyxids (plasmodiophorids) in marine ecosystems - a review
Authors: Neuhauser Sigrid , Kirchmair Martin , Gleason Frank H.
Published: April 2011

Phytomyxea (plasmodiophorids) is an enigmatic group of obligate biotrophic parasites. Most of the known 41 species are associated with terrestrial and freshwater ecosystems. However, the potential of phytomyxean species to influence marine ecosystems either directly by causing diseases of their hosts or indirectly as vectors of viruses is enormous, although still unexplored. In all, 20% of the currently described phytomyxean species are parasites of some of the key primary producers in the ocean, such as seagrasses, brown algae and diatoms; however, information on their distribution, abundance and biodiversity is either incomplete or lacking. Phytomyxean species influence fitness by altering the metabolism and/or the reproductive success of their hosts. The resulting changes can (1) have an impact on the biodiversity within host populations, and (2) influence microbial food webs because of altered availability of nutrients (e.g. changed metabolic status of host, transfer of organic matter). Also, phytomyxean species may affect their host populations indirectly by transmitting viruses. The majority of the currently known single-stranded RNA marine viruses structurally resemble the viruses transmitted by phytomyxean species to crops in agricultural environments. Here, we explore possible ecological roles of these parasites in marine habitats; however, only the inclusion of Phytomyxea in marine biodiversity studies will allow estimation of the true impact of these species on global primary production in the oceans.
Topology of surface diagrams of smooth 4-manifolds
Authors: Williams Jonathan D.
Published: April 2011

Surface diagrams are a new way to specify any smooth closed orientable 4-manifold by an orientable surface decorated with simple closed curves. These curves are cyclically indexed, and each curve has a unique transverse intersection with the next. The aim of this paper is to announce a uniqueness theorem for these objects (within a fixed homotopy class) that turns out to be similar to the Reidemeister-Singer theorem for Heegaard splittings of 3-manifolds.
Equivalence of Heegaard Floer homology and embedded contact homology via open book decompositions
Authors: Colin Vincent , Ghiggini Paolo , Honda Ko
Published: April 2011

We sketch the proof of the equivalence between the hat versions of Heegaard Floer homology and embedded contact homology (ECH). The key point is to express these two Floer homology theories in terms of an open book decomposition of the ambient manifold.
Feed-forward mechanism of converting biochemical cooperativity to mitotic processes at the kinetochore plate
Authors: Park Jung-Eun , Erikson Raymond L. , Lee Kyung S.
Published: April 2011

The feed-forward mechanism is observed in some of the intracellular events, such as metabolic and transcriptional regulatory networks, but not in dynamic mitotic processes. Mammalian polo-like kinase 1 (Plk1) rapidly accumulates at centrosomes and kinetochores as cells enter mitosis. Plk1 function is spatially regulated through the targeting activity of the polo-box domain (PBD) that binds to a phosphoepitope generated by either cyclin dependent kinase 1 (Cdk1) (non-self-priming) or Plk1 itself (self-priming). “Non-self-priming and binding” is thought to ensure the orderly execution of cell cycle events. The physiological significance of the “self-priming and binding” is unknown. Using a pair of ELISA, here we demonstrated that mutations of the self-priming site of a kinetochore component, PBIP1/MLF1IP/KLIP1/CENP-50/CENP-U (PBIP1), to a Cdk1-dependent non-self-priming site abolished product-activated cooperativity in the formation of the Plk1–PBIP1 complex. Both PBD-dependent “two-dimensional” interaction with surface-restricted PBIP1 and subsequent phosphorylation of PBIP1 by anchored Plk1 were crucial to cooperatively generate the Plk1–PBIP1 complex. Highlighting the importance of this mechanism, failure in this process resulted in improper Plk1 recruitment to kinetochores, mitotic arrest, chromosome missegregation, and apoptosis. Thus, Plk1 PBD-dependent biochemical cooperativity is tightly coupled to mitotic events at the kinetochore plate through a product-activated, feed-forward mechanism. Given the critical role of self-priming and binding in the recruitment of Plk1 to surface-confined structures, such as centrosomes, kinetochores, and midbody, we propose that the observed feed-forward mechanism serves as a fundamental biochemical process that ensures dynamic nature of Plk1 localization to and delocalization from these subcellular locations.
TAAR1 activation modulates monoaminergic neurotransmission, preventing hyperdopaminergic and hypoglutamatergic activity
Authors: Revel Florent G. , Moreau Jean-Luc , Gainetdinov Raul R. , Bradaia Amyaouch , Sotnikova Tatyana D. , Mory Roland , Durkin Sean , Zbinden Katrin Groebke , Norcross Roger , Meyer Claas A. , Metzler Veit , Chaboz Sylvie , Ozmen Laurence , Trube Gerhard , Pouzet Bruno , Bettler Bernhard , Caron Marc G. , Wettstein Joseph G. , Hoener Marius C.
Published: April 2011

The trace amine-associated receptor 1 (TAAR1), activated by endogenous metabolites of amino acids like the trace amines p-tyramine and β-phenylethylamine, has proven to be an important modulator of the dopaminergic system and is considered a promising target for the treatment of neuropsychiatric disorders. To decipher the brain functions of TAAR1, a selective TAAR1 agonist, RO5166017, was engineered. RO5166017 showed high affinity and potent functional activity at mouse, rat, cynomolgus monkey, and human TAAR1 stably expressed in HEK293 cells as well as high selectivity vs. other targets. In mouse brain slices, RO5166017 inhibited the firing frequency of dopaminergic and serotonergic neurons in regions whereTaar1is expressed (i.e., the ventral tegmental area and dorsal raphe nucleus, respectively). In contrast, RO5166017 did not change the firing frequency of noradrenergic neurons in the locus coeruleus, an area devoid ofTaar1expression. Furthermore, modulation of TAAR1 activity altered the desensitization rate and agonist potency at 5-HT1Areceptors in the dorsal raphe, suggesting that TAAR1 modulates not only dopaminergic but also serotonergic neurotransmission. In WT but notTaar1−/−mice, RO5166017 prevented stress-induced hyperthermia and blocked dopamine-dependent hyperlocomotion in cocaine-treated and dopamine transporter knockout mice as well as hyperactivity induced by an NMDA antagonist. These results tie TAAR1 to the control of monoamine-driven behaviors and suggest anxiolytic- and antipsychotic-like properties for agonists such as RO5166017, opening treatment opportunities for psychiatric disorders.
Colour Correspondence Effects between Controlled Objects and Targets
Authors: Miles James D. , Proctor Robert W.
Published: April 2011

It is increasingly popular to use movement trajectories as a measure of mental processes related to task performance. Often this is accomplished by moving a cursor to a target on a computer screen. However, the relation between features of the cursor and the targets is rarely, if at all, considered. In five experiments, we examined whether moving a cursor to a target was affected by the relation between their colours, even when this relation was task irrelevant. In Experiments 1–3, a mouse-controlled cursor was moved to one of two coloured targets. Results showed colour correspondence effects in latency to initiate a response, duration of movement times, and movement trajectories when the relationship between cursor and target colours was task relevant (Experiment 1) and when only the cursor colour was task relevant (Experiment 2), but not when only the target was task relevant (Experiment 3). Follow-up experiments using single targets showed that colour correspondence effects occurred as long as attention was dedicated to the colour of the cursor, even when neither the cursor nor the target colour was relevant to selecting the correct movement (Experiments 4 and 5). Furthermore, when the relation between cursor and target colours is task irrelevant, colour correspondence effects for response initiation times are uncorrelated with those for movement times and movement trajectories. We interpret the observed correspondence effect in terms of response coding, although attention cueing may also play a role, and suggest that greater consideration of cursor features is needed when examining movement trajectories in choice reaction tasks.
Production of hydrogen via conversion of hydrocarbons using a microwave plasma
Authors: Jasiński Mariusz , Dors Mirosław , Nowakowska Helena , Nichipor Gerietta V , Mizeraczyk Jerzy
Published: April 2011

In this paper, results of hydrogen production from hydrocarbons in an atmospheric pressure microwave plasma are presented. As sources of hydrogen, both methane CH4 and tetrafluoroethane C2H2F4 were tested. A new waveguide-based nozzleless cylinder-type microwave plasma source was used to convert hydrocarbons into hydrogen. The processed gaseous hydrocarbons were introduced into the plasma by four gas ducts which formed a swirl flow in the plasma reactor. The absorbed microwave power was up to 5 kW. The gas flow rate was up to 212 L min−1. The hydrogen mass yield rate and the corresponding energetic hydrogen mass yield were up to 866 g[H2] h−1 and 577 g [H2] kWh−1 of microwave energy absorbed by the plasma, respectively. These parameters are better than our previous results when nitrogen was used as a swirl gas and much better than those typical for other plasma methods of hydrogen production (electron beam, gliding arc, plasmatron).
3D static and time-dependent modelling of a dc transferred arc twin torch system
Authors: Colombo V , Ghedini E , Boselli M , Sanibondi P , Concetti A
Published: April 2011

The transferred arc plasma torch device consists of two electrodes generating a plasma arc sustained by means of an electric current flowing through the body of the discharge. Modelling works investigating transferred electric arc discharges generated between two suspended metallic electrodes, in the so-called twin torch configuration, are scarce. The discharge generated by this particular plasma source configuration is characterized by a complex shape and fluid dynamics and needs a 3D description in order to be realistically predicted. The extended discharge length that goes from the tungsten pencil cathode to the flat copper anode without any particular confinement wall and the fluid dynamics and magnetic forces acting on the arc may induce an unsteady behaviour. In order to capture the dynamic behaviour of a twin torch discharge, a 3D time-dependent plasma arc model has been developed using a customized commercial code FLUENT form in both local thermodynamic equilibrium (LTE) and non-LTE. A two temperature (2T) model has been developed taking into account only the thermal non-equilibrium effects in argon plasma. The main differences between LTE and 2T models' results concern the increased extension of the horizontal section of the discharge and the predicted reduced (of about 60–80 V) voltage drop between the electrodes when using a 2T model.
A finite volume model for multi-component diffusion in magnetically confined plasmas
Authors: Peerenboom K S C , van Dijk J , Goedheer W J , Degrez G , van der Mullen J J A M
Published: April 2011

In partially ionized, magnetically confined plasmas, the diffusive fluxes of different species are coupled. Additionally, the fluxes are directionally coupled due to the Lorentz force. The challenge in the modelling of multi-component, magnetized plasmas is to take care of this coupling in the numerical method. In this paper, a complex form of the Stefan–Maxwell equations is used to account for the coupling between the flow directions. To handle the coupling between the species fluxes in the finite volume method, a generalized, coupled form of the exponential scheme is used. The presented numerical method is applied to a magnetically confined hydrogen jet. The results show that the numerical method is capable of describing typical characteristics of magnetized plasmas, such as anisotropic diffusion and the presence of a pressure gradient sustained by the Lorentz force.
Manufacturing nanostructured YSZ coatings by suspension plasma spraying (SPS): effect of injection parameters
Authors: Meillot E , Vert R , Caruyer C , Damiani D , Vardelle M
Published: April 2011

The suspension plasma spraying process is investigated using shadow imaging techniques to appreciate the different trajectories of the liquid jet interacting with a dc high-energy plasma flow. Then, the modelling of different liquid injections (isolated droplet, train of droplets and continuous jet) helps us to determine which injection type must be preferred. From that, coating depositions have been carried out with yttria zirconia suspension. Trajectory deviations at impact have been measured depending on the injection pressure and injection location. Coatings have been realized under the same operating investigations and their microstructures and mechanical properties have been characterized.
Innovative and emerging processes in plasma spraying: from micro- to nano-structured coatings
Authors: Fauchais P , Vardelle A
Published: April 2011

In the context of nanometre-sized structured materials and the perspectives of their technological applications, plasma spray technology is developing to master the coating microstructure at a nanometre scale level. This paper is an attempt to describe (i) the latest advances in the control of the conventional plasma spray process that requires the monitoring of both the plasma jet fluctuation level and particle processing and (ii) the innovative plasma spray processes that have recently emerged. The latter can be ranked in two classes: the processes that use a liquid feedstock where coatings are essentially formed by the impact of molten particles and droplets; and the processes that generally use a powder feedstock where coatings are generated by the condensation of a vapour with possible inclusion of nanometre-sized particles. Their potential applications are briefly presented and it is concluded that they should develop into viable technologies in the near future.
Improvements of radiative transfer calculation for SF6 thermal plasmas
Authors: Randrianandraina H Z , Cressault Y , Gleizes A
Published: April 2011

We present a comparison between an exact calculation of radiative transfer in SF6 thermal plasma based on a fine description of the spectrum with 300 000 spectral points for each temperature value, for simplified conditions (1D and 2D geometries with imposed symmetrical temperature profiles and local thermodynamic equilibrium) and two kinds of approximated calculations. The first is the classical net emission coefficient largely used in arc modelling. The second one is based on a very simplified spectral description with only seven intervals assuming a grey body condition within each interval and using the Planck and the Rosseland averaging for deducing the mean absorption coefficient (MAC). At high temperature the use of the Rosseland averaging is not satisfactory. The other two approximated methods (net emission and the Planck averaging) are acceptable but the radiative flux is in general not very accurate. The radiative transfer calculation can be improved following three ways: a better knowledge of the basic processes and in particular of the absorption coefficients for diatomic and polyatomic molecules, the use of different definitions of MACs (Planck averaging at high temperature and mean natural value at low temperature) and a careful choice of the spectral intervals.