Induction and recovery of estrogenic effects after short-term 17ß-estradiol exposure in juvenile rainbow trout (Oncorhynchus mykiss).

Estrogenic compounds found in the aquatic environment include natural and synthetic estrogen hormones as well as other less potent estrogenic xenobiotics. In this study, a comprehensive approach was used to examine effects on fish endocrine system endpoints during a short-term xenoestrogen exposure as well as after post-exposure recovery. Rainbow trout (Oncorhynchus mykiss) were exposed to an aqueous 17ß-estradiol (E2) concentration of 0.473 µg l(-1) for 2 and 7 days (d) followed by a 14-d recovery period. At d2 and d7, plasma E2 concentrations in treated fish were 458- and 205-fold higher than in control fish and 23- and 16-fold higher than the exposure water concentration. E2 treatment resulted in significant increases in hepatosomatic index (HSI), plasma vitellogenin (VTG) protein concentrations, and liver VTG and estrogen receptor alpha mRNA levels. All of these parameters, with the exception of plasma VTG protein, returned to baseline values during the recovery period. Plasma cortisol concentrations were unaffected by treatment. This research shows varied time frames of the estrogen-responsive molecular-, biochemical-, and tissue-level alterations, as well as their persistence, in juvenile rainbow trout treated with aqueous E2. These results have implications for feral rainbow trout exposed to xenoestrogens and indicate the importance of evaluating a comprehensive suite of endpoints in assessing the impact of this type of environmental contaminant.

Elevation angle alignment of quasi optical receiver mirrors of collective Thomson scattering diagnostic by sawtooth measurements.

Localized measurements of the fast ion velocity distribution function and the plasma composition measurements are of significant interest for the fusion community. Collective Thomson scattering (CTS) diagnostics allow such measurements with spatial and temporal resolution. Localized measurements require a good alignment of the optical path in the transmission line. Monitoring the alignment during the experiment greatly benefits the confidence in the CTS measurements. An in situ technique for the assessment of the elevation angle alignment of the receiver is developed. Using the CTS diagnostic on TEXTOR without a source of probing radiation in discharges with sawtooth oscillations, an elevation angle misalignment of 0.9° was found with an accuracy of 0.25°.

Effects of the veterinary pharmaceutical salinomycin and its formulation on the plant Brassica rapa.

Veterinary pharmaceuticals are emerging contaminants found throughout the environment, and their presence and effects are a matter of concern. The purpose of this study was to compare the phytotoxicity of salinomycin (pure compound = 96 %) and Sacox 120 (formulated product = 120 g salinomycin/kg) to the plant species Brassica rapa as well as to investigate salinomycin persistence in soil. Calculated EC/IC(50) values for salinomycin and Sacox 120 were 1.10 and 2.88 and 2.19 and 18.03 mg/kg, respectively, based on salinomycin concentration. For exposure of B. rapa to salinomycin, significant adverse effects were observed for growth end points at the greater concentrations. For the reproduction end point (i.e., number of buds), as well as root length and wet mass, significant differences were observed at the lower concentrations (stimulating growth) and adverse effects at the greater concentrations. This study confirmed that the toxic effects of Sacox 120 are attributable to the active ingredient salinomycin. Liquid chromatography-electrospray ionization-mass spectrometry analyses confirmed that exposure concentrations of salinomycin were 90 and 83 % of the nominal concentrations, respectively, in the soils amended with either pure or formulated product. At the end of the experiment, after 14 days, salinomycin concentrations for both tests (salinomycin and Sacox 120) decreased to 6.2 and 5.8 % of the nominal exposure concentrations, respectively. Detected salinomycin concentrations in plant shoots ranged from 3.47 to 41.0 ng/g dry shoot. This study shows the importance of using plants as tools to evaluate environmental risk and as a bridge to relate environment and human health risks.

Design and performance of the collective Thomson scattering receiver at ASDEX Upgrade.

Here we present the design of the fast-ion collective Thomson scattering receiver for millimeter wave radiation installed at ASDEX Upgrade, a tokamak for fusion plasma experiments. The receiver can detect spectral power densities of a few eV against the electron cyclotron emission background on the order of 100 eV under presence of gyrotron stray radiation that is several orders of magnitude stronger than the signal to be detected. The receiver down converts the frequencies of scattered radiation (100-110 GHz) to intermediate frequencies (IF) (4.5-14.5 GHz) by heterodyning. The IF signal is divided into 50 IF channels tightly spaced in frequency space. The channels are terminated by square-law detector diodes that convert the signal power into DC voltages. We present measurements of the transmission characteristics and performance of the main receiver components operating at mm-wave frequencies (notch, bandpass, and lowpass filters, a voltage-controlled variable attenuator, and an isolator), the down-converter unit, and the IF components (amplifiers, bandpass filters, and detector diodes). Furthermore, we determine the performance of the receiver as a unit through spectral response measurements and find reasonable agreement with the expectation based on the individual component measurements.

Measurements of intrinsic ion Bernstein waves in a tokamak by collective Thomson scattering.

In this Letter we report measurements of collective Thomson scattering (CTS) spectra with clear signatures of ion Bernstein waves and ion cyclotron motion in tokamak plasmas. The measured spectra are in accordance with theoretical predictions and show clear sensitivity to variation in the density ratio of the main ion species in the plasma. Measurements with this novel diagnostic demonstrate that CTS can be used as a fuel ion ratio diagnostic in burning fusion plasma devices.

Development of novel fuel ion ratio diagnostic techniques.

To overcome the challenge of measuring the fuel ion ratio in the core (ρ<0.3) of ITER, a coordinated effort aiming at developing diagnostic techniques has been initiated. The investigated techniques are novel uses or further development of existing methods such as charge exchange recombination spectrometry, neutron spectrometry, and collective Thomson scattering. An overview of the work on the three diagnostic techniques is presented.

Collective Thomson scattering measurements with high frequency resolution at TEXTOR.

We discuss the development and first results of a receiver system for the collective Thomson scattering (CTS) diagnostic at TEXTOR with frequency resolution in the megahertz range or better. The improved frequency resolution expands the diagnostic range and utility of CTS measurements in general and is a prerequisite for measurements of ion Bernstein wave signatures in CTS spectra. The first results from the new acquisition system are shown to be consistent with theory and with simultaneous measurements by the standard receiver system.

Broadband notch filter design for millimeter-wave plasma diagnostics.

Notch filters are integrated in plasma diagnostic systems to protect millimeter-wave receivers from intensive stray radiation. Here we present a design of a notch filter with a center frequency of 140 GHz, a rejection bandwidth of ∼900 MHz, and a typical insertion loss below 2 dB in the passband of ±9 GHz. The design is based on a fundamental rectangular waveguide with eight cylindrical cavities coupled by T-junction apertures formed as thin slits. Parameters that affect the notch performance such as physical lengths and conductor materials are discussed. The excited resonance mode in the cylindrical cavities is the fundamental TE(11). The performance of the constructed filter is measured using a vector network analyzer monitoring a total bandwidth of 30 GHz. We compare the measurements with numerical simulations.

Veterinary pharmaceuticals and antibiotic resistance of Escherichia coli isolates in poultry litter from commercial farms and controlled feeding trials.

Veterinary pharmaceuticals are commonly used in poultry farming to prevent and treat microbial infections as well as to increase feed efficiency, but their use has created public and environmental health concerns. Poultry litter contains antimicrobial residues and resistant bacteria; when applied as fertilizer, the level and effects of these pharmaceuticals and antimicrobial-resistant bacteria in the environment are of concern. The purpose of this study was to investigate poultry litter for veterinary pharmaceuticals and resistance patterns of Escherichia coli. Litter samples were collected from controlled feeding trials and from commercial farms. Feed additives bacitracin, chlortetracycline, monensin, narasin, nicarbazin, penicillin, salinomycin, and virginiamycin, which were present in the feed on commercial farms and added to the feed in the controlled trials, were extracted in methanol and analyzed by liquid chromatography-mass spectrometry techniques. Sixty-nine E. coli were isolated and identified by API 20E. The susceptibility of the isolates to antibiotics was determined using Avian plates and the Sensititer automated system. This study confirmed the presence of antimicrobial residues in broiler litter from controlled environments as well as commercial farms, ranging from 0.07 to 66 mg/L depending on the compound. Concentrations of individual residues were higher in litter from controlled feeding trials than those from commercial farms. All E. coli isolates from commercial farms were multiresistant to at least 7 antibiotics. Resistance to beta-lactam antibiotics (amoxicillin, ceftiofur), tetracyclines, and sulfonamides was the most prevalent. This study concluded that broiler litter is a source of antimicrobial residues and represents a reservoir of multiple antibiotic-resistant E. coli.

Antenna design for fast ion collective Thomson scattering diagnostic for the international thermonuclear experimental reactor.

Fast ion physics will play an important role for the international thermonuclear experimental reactor (ITER), where confined alpha particles will affect and be affected by plasma dynamics and thereby have impacts on the overall confinement. A fast ion collective Thomson scattering (CTS) diagnostic using gyrotrons operated at 60 GHz will meet the requirements for spatially and temporally resolved measurements of the velocity distributions of confined fast alphas in ITER by evaluating the scattered radiation (CTS signal). While a receiver antenna on the low field side of the tokamak, resolving near perpendicular (to the magnetic field) velocity components, has been enabled, an additional antenna on the high field side (HFS) would enable measurements of near parallel (to the magnetic field) velocity components. A compact design solution for the proposed mirror system on the HFS is presented. The HFS CTS antenna is located behind the blankets and views the plasma through the gap between two blanket modules. The viewing gap has been modified to dimensions 30x500 mm(2) to optimize the CTS signal. A 1:1 mock-up of the HFS mirror system was built. Measurements of the beam characteristics for millimeter-waves at 60 GHz used in the mock-up agree well with the modeling.

Commissioning activities and first results from the collective Thomson scattering diagnostic on ASDEX Upgrade (invited).

The collective Thomson scattering (CTS) diagnostic installed on ASDEX Upgrade uses millimeter waves generated by the newly installed 1 MW dual frequency gyrotron as probing radiation at 105 GHz. It measures backscattered radiation with a heterodyne receiver having 50 channels (between 100 and 110 GHz) to resolve the one-dimensional velocity distribution of the confined fast ions. The steerable antennas will allow different scattering geometries to fully explore the anisotropic fast ion distributions at different spatial locations. This paper covers the capabilities and operational limits of the diagnostic. It then describes the commissioning activities carried out to date. These activities include gyrotron studies, transmission line alignment, and beam pattern measurements in the vacuum vessel. Overlap experiments in near perpendicular and near parallel have confirmed the successful alignment of the system. First results in near perpendicular of scattered spectra in a neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH) plasma (minority hydrogen) on ASDEX Upgrade have shown evidence of ICRH heating phase of hydrogen.

Investigation of first mirror heating for the collective Thomson scattering diagnostic in ITER.

Collective Thomson scattering (CTS) has the capabilities to measure phase space densities of fast ion populations in ITER resolved in configuration space, in velocity space, and in time. In the CTS system proposed for ITER, probing radiation at 60 GHz generated by two 1 MW gyrotrons is scattered in the plasma and collected by arrays of receivers. The transmission lines from the gyrotrons to the plasma and from the plasma to the receivers contain several quasioptical mirrors among other components. These are designed to produce astigmatic beam patterns in the plasma where the beam shapes will have a direct impact on the signal strength of the diagnostic, the spatial resolution, and the robustness of probe and receiver beam overlap against density excursions. The first mirror has a line of sight to the plasma and is thus exposed to severe neutron streaming. The present neutronics and thermomechanical modeling of a first mirror on the high field side indicates that the mirror curvature may warp due to heating. This may alter the beam quality, and therefore, thermal effects have to be accounted for during the design of the mirror. The modeling further demonstrates that thin mirrors are superior to thick mirrors from a thermomechanical point of view.

Transport and dynamics of molecules dissolved in maize root cortex membranes.

Translational diffusion of a fluorescent sterol probe was measured in the plasma membranes of protoplasts isolated from cortical cells of the primary root of maize seedlings. The apparent lateral diffusion coefficient was typically observed to be nearly insensitive to temperature, while the mobile fraction increased with increasing temperature. These fluorescence photobleaching recovery (FPR) measurements were compared with the electron paramagnetic resonance (EPR) spectra of the methyl ester of 13-doxyl palmitic acid in membranes of corn root tissue in situ. The complex spectra observed with this probe were analyzed as weighted sums of simpler spectra of various order parameters and rotational correlation times. The reconstituted spectra calculated from the model show that EPR also detects a mobile (less ordered, fluid) fraction, distinguished by the order parameter S = 0.1 to 0.2, which becomes more abundant as temperature increases and is qualitatively comparable to the mobile fraction determined by the FPR method. The observed results on the mobile fractions and the diffusion rates for translational (FPR) as well as rotational (EPR) motions are interpreted in terms of membrane organization, thus providing information on the population and structural patterns of the coexisting domains with a special emphasis on the response of the membrane to temperature changes.

Selective osmotic effect on diffusion of plasma membrane lipids in maize protoplasts.

Osmotic levels in the range typically used during plant protoplast isolation and incubation were investigated with regard to effects on the lateral diffusion of lipid probes in the plasma membrane. The lateral diffusion coefficient of a fluorescent sterol probe in the plasma membrane of maize (Zea mays L.) root protoplasts in a medium containing 0.45 M mannitol was 4 times faster than when the medium contained 0.9 M mannitol. The lateral diffusion coefficient of a fluorescent phospholipid probe, however, did not change over this range of mannitol concentrations. Similar diffusion characteristics were observed when the medium contained trehalose instead of mannitol. Slower lateral diffusion of the sterol probe at higher osmolality was also observed when KCl/CaCl2-based osmotic media were used with protoplasts isolated by a mechanical, rather than by an enzymic, method. Extraction and quantitation of total lipids from protoplasts showed that both the phospholipid and sterol contents per protoplast decreased with increasing osmolality, while the sterol/phospholipid ratio increased. These results demonstrate that osmotic stress induces selective changes in both the composition and biophysical properties of plant membranes.