Observation of Flat Electron Temperature Profiles in the Lithium Tokamak Experiment.

It has been predicted for over a decade that low-recycling plasma-facing components in fusion devices would allow high edge temperatures and flat or nearly flat temperature profiles. In recent experiments with lithium wall coatings in the Lithium Tokamak Experiment (LTX), a hot edge (>200 eV) and flat electron temperature profiles have been measured following the termination of external fueling. Reduced recycling was demonstrated by retention of ∼60% of the injected hydrogen in the walls following the discharge. Electron energy confinement followed typical Ohmic confinement scaling during fueling, but did not decrease with density after fueling terminated, ultimately exceeding the scaling by ∼200%. Achievement of the low-recycling, hot edge regime has been an important goal of LTX and lithium plasma-facing component research in general, as it has potentially significant implications for the operation, design, and cost of fusion devices.

Molecular diagnosis on tissues and cells: how it affects training and will affect practice in the future.

On 25th November 2011, a symposium organized by the Royal College of Pathologists, entitled 'Molecular diagnosis on tissues and cells', took place in London. As trainees in histopathology and cytopathology, we were stimulated to consider the role that molecular biology is likely to play in future practice and how this is addressed by our own training. The symposium provided a basis for this article. Routine samples requiring molecular analysis are equally relevant to histopathologists and cytopathologists, and molecular biology laboratories are now using cytological as well as histological material for diagnostic testing, allowing different specimen types to be used as and when they are most appropriate. The most widely used types of molecular analysis in routine cellular pathology are EGFR testing in lung cancer, molecular testing of thyroid nodules, fluorescence in situ hybridization testing of urine samples, clonality analysis in lymphoma testing, HER2 testing in breast and gastric cancer, KRAS testing in colorectal cancer, intraoperative assessment of breast cancer sentinel nodes, molecular testing of gastrointestinal stromal tumours and mismatch repair protein analysis. Of these, the majority in the UK are carried out on histopathology samples, although many are applicable to cytological samples if adequate material is obtained. We are particularly encouraged by the potential of molecular diagnostic cytology in traditionally difficult areas, such as intraoperative assessment. We believe that increasing reliance on molecular diagnostic techniques will also herald changes in training.

Feasibility study of a high spatial and time resolution beam emission spectroscopy diagnostic for localized density fluctuation measurements in Lithium Tokamak eXperiment-ß (LTX-ß).

Trapped electron mode (TEM) is the main source of turbulence predicted for the unique operation regime of a flat temperature profile under low-recycling conditions in the LTX-ß tokamak, while ion temperature gradient driven turbulence may also occur with gas fueling from the edge. To investigate mainly TEM scale density fluctuations, a high spatial and time resolution 2D beam emission spectroscopy (BES) diagnostic is being developed. Apart from spatially localized density turbulence measurement, BES can provide turbulence flow and flow shear dynamics. This BES system will be realized using an avalanche photodiode-based camera and narrow band interference filter. The system can acquire data at 2 MHz. Simulations with the Simulation of Spectra (SOS) code indicate that a high signal to noise ratio can be achieved with the proposed system. This will enable sampling the density fluctuations at this high time resolution. The design considerations and system optimization using the SOS code are presented.

Continuous improvement of H-mode discharge performance with progressively increasing lithium coatings in the National Spherical Torus Experiment.

Lithium wall coatings have been shown to reduce recycling, improve energy confinement, and suppress edge localized modes in the National Spherical Torus Experiment. Here, we show that these effects depend continuously on the amount of predischarge lithium evaporation. We observed a nearly monotonic reduction in recycling, decrease in electron transport, and modification of the edge profiles and stability with increasing lithium. These correlations challenge basic expectations, given that even the smallest coatings exceeded that needed for a nominal thickness of the order of the implantation range.

A simple vacuum suitcase for enabling plasma facing component characterization in fusion devices.

We have demonstrated a vacuum suitcase to transport samples in vacuo to a surface analysis station for characterization of tokamak plasma facing components (PFCs). This technique enables surface analysis at powerful, dedicated stations that are not encumbered by design constraints imposed on them by a tokamak. The vacuum suitcase is an alternative solution to characterizing PFCs using diagnostics that are designed and built around a tokamak. The vacuum suitcase, called the Sample Exposure Probe (SEP), features mobile ultra-high vacuum pumping. Active pumping under high vacuum enables sample transfer between the Lithium Tokamak eXperiment-ß (LTX-ß) and a high resolution X-ray Photoelectron Spectroscopy (XPS) system that is situated close by. A thermocouple inserted in the back of the sample head measures heat flux from the plasma during exposure, and together with a button heater, allows the sample to match the LTX-ß PFCs in high temperature operations. As vacuum conditions are better during transfer and analysis than in the tokamak, less contamination is introduced to the samples. XPS scans on a dedicated analysis station enable peak identification due to higher resolution and signal to noise ratio. A similar probe could be implemented for other fusion devices. The SEP is the first vacuum suitcase implementation for fusion applications that incorporates active pumping.

The charge exchange recombination spectroscopy diagnostic on the upgraded Lithium Tokamak eXperiment (LTX-ß).

The Lithium Tokamak eXperiment has undergone an upgrade to LTX-ß, a major part of which is the addition of neutral beam injection (NBI). NBI has allowed for a new charge exchange recombination spectroscopy (CHERS) system to be installed in order to measure impurity concentrations, ion temperature, and toroidal velocity. Previously on LTX measuring these parameters relied on passive spectroscopy and inversion techniques and had large uncertainty. The CHERS system has 52 total views, split into four groups of 13, half facing toward the beam and half symmetrically facing away from the beam, so the background non-beam related emission can be simultaneously subtracted. Both sets of views sample a major radius of 27-59 cm, with resolution through the beam of 1.5-2.5 cm. LTX-ß is expected to have its magnetic axis near 35 cm, with minor radii of 18-23 cm. Three separate spectrometers will be used for the diagnostic, giving the system great flexibility to simultaneously measure emission from multiple impurity lines. The viewing optics are f/1.8, allowing all of the spectrometers to be fully illuminated. Design and calibration of the system as well as the advantages of various configurations of the spectrometers will be highlighted.

Magnetic perturbation diagnostics in the high-temperature lithiated environment of LTX-ß.

Magnetic perturbation measurements will be invaluable for characterizing Lithium Tokamak Experiment Beta (LTX-ß) plasmas due to the time-evolving 3D nature of the magnetic fields generated by eddy currents in the vessel and copper shell segments, as well as enhanced MHD instability drive due to newly introduced neutral beam heating. The LTX-ß upgrade includes two new arrays of Mirnov coils: a shell eddy sensor array of two-axis coils distributed over the back surface of one shell segment and a toroidal array of poloidal field coils at the low-field side midplane gap. Evaporative lithium wall-coating and the high temperatures required for liquid lithium wall operation both complicate the implementation of in-vessel diagnostics. While the shell array is protected from lithium exposure, the shell segment to which it is mounted will at times exceed 300 °C. The toroidal array, however, will experience direct line-of-sight exposure to the lithium evaporator as well as close proximity to the hot shell and may also be subject to poorly confined beam-driven fast ions. We describe how the two new Mirnov coil arrays meet these environmental challenges and enhance the LTX-ß diagnostic suite.

Millimeter-wave interferometry and far-forward scattering for density fluctuation measurements on LTX-ß.

The λ ≈ 1 mm (f = 288 GHz) interferometer for the Lithium Tokamak Experiment-ß (LTX-ß) will use a chirped-frequency source and a centerstack-mounted retro-reflector mirror to provide electron line density measurements along a single radial chord at the midplane. The interferometer is unique in the use of a single source (narrow-band chirped-frequency interferometry) and a single beam splitter for separating and recombining the probe and reference beams. The current work provides a documentation of the interferometry hardware and evaluates the capabilities of the system as a far-forward collective scattering diagnostic. As such, the current optical setup is estimated to have a detection range of 0.4 ≲ k ⊥ ≲ 1.7 cm-1, while an improved layout will extend the upper k ⊥ limit to ∼3 cm-1. Measurements with the diagnostic on LTX are presented, showing interferometry results and scattered signal data. These diagnostics are expected to provide routine measurements on LTX-ß for high frequency coherent density oscillations (e.g., Alfvénic modes during neutral beam injection) as well as for broadband turbulence.

A frequency-modulated continuous-wave reflectometer for the Lithium Tokamak Experiment.

The frequency-modulated continuous-wave reflectometer on LTX (Lithium Tokamak Experiment) and the data analysis methods used for determining electron density profiles are described. The diagnostic uses a frequency range of 13.1-33.5 GHz, for covering a density range of 0.21-1.4×1013 cm-3 (in O-mode polarization) with a time resolution down to 8 µs. The design of the diagnostic incorporates the concept of an "optimized" source frequency sweep, which minimizes the large variation in the intermediate frequency signal due to a long dispersive transmission line. The quality of the raw data is dictated by the tuning characteristics of the microwave sources, as well as the group delay ripple in the transmission lines, which can generate higher-order nonlinearities in the frequency sweep. Both effects are evaluated for our diagnostic and best practices are presented for minimizing "artifacts" generated in the signals. The quality of the reconstructed profiles is also improved using two additional data analysis methods. First, the reflectometer data are processed as a radar image, where clutter due to echoes from the wall and backscattering from density fluctuations can be easily identified and removed. Second, a weighed least-squares lamination algorithm POLAN (POLynomial ANalysis) is used to reconstruct the electron density profile. Examples of density profiles in LTX are presented, along with comparisons to measurements from the Thomson scattering and the λ = 1 mm interferometer diagnostics.

High-resolution grazing-incidence grating spectrometer for temperature measurements of low-Z ions emitting in the 100-300 Å spectral band.

We have constructed a high-resolution grazing-incidence spectrometer designed for measuring the ion temperature of low-Z elements, such as Li(+) or Li(2 +), which radiate near 199 Å and 135 Å, respectively. Based on measurements at the Livermore Electron Beam Ion Trap we have shown that the instrumental resolution is better than 48 mÅ at the 200 Å setting and better than 40 mÅ for the 135-Å range. Such a high spectral resolution corresponds to an instrumental limit for line-width based temperature measurements of about 45 eV for the 199 Å Li(+) and 65 eV for the 135 Å Li(2 +) lines. Recently obtained survey spectra from the Lithium Tokamak Experiment at the Princeton Plasma Physics Laboratory show the presence of these lithium emission lines and the expected core ion temperature of approximately 70 eV is sufficiently high to demonstrate the feasibility of utilizing our high-resolution spectrometer as an ion-temperature diagnostic.

Development progress of the Materials Analysis and Particle Probe.

The Materials Analysis and Particle Probe (MAPP) is a compact in vacuo surface science diagnostic, designed to provide in situ surface characterization of plasma facing components in a tokamak environment. MAPP has been implemented for operation on the Lithium Tokamak Experiment at Princeton Plasma Physics Laboratory (PPPL), where all control and analysis systems are currently under development for full remote operation. Control systems include vacuum management, instrument power, and translational/rotational probe drive. Analysis systems include onboard Langmuir probes and all components required for x-ray photoelectron spectroscopy, low-energy ion scattering spectroscopy, direct recoil spectroscopy, and thermal desorption spectroscopy surface analysis techniques.

Spectral emission measurements of lithium on the lithium tokamak experiment.

There has been a long-standing collaboration between ORNL and PPPL on edge and boundary layer physics. As part of this collaboration, ORNL has a large role in the instrumentation and interpretation of edge physics in the lithium tokamak experiment (LTX). In particular, a charge exchange recombination spectroscopy (CHERS) diagnostic is being designed and undergoing staged testing on LTX. Here we present results of passively measured lithium emission at 5166.89 A in LTX in anticipation of active spectroscopy measurements, which will be enabled by the installation of a neutral beam in 2013. Preliminary measurements are made in transient LTX plasmas with plasma current, I(p) < 70 kA, ohmic heating power, P(oh) ∼ 0.3 MW and discharge lifetimes of 10-15 ms. Measurements are made with a short focal length spectrometer and optics similar to the CHERS diagnostics on NSTX [R. E. Bell, Rev. Sci. Instrum. 68(2), 1273-1280 (1997)]. These preliminary measurements suggest that even without the neutral beam for active spectroscopy, there is sufficient passive lithium emission to allow for line-of-sight profile measurements of ion temperature, T(i); toroidal velocity and v(t). Results show peak T(i) = 70 eV and peak v(t) = 45 km/s were reached 10 ms into the discharge.

Peritoneal stromal endometriosis: a detailed morphological analysis of a large series of cases of a common and under-recognised form of endometriosis.

AIMS: It is generally considered that an unequivocal histological diagnosis of endometriosis requires the presence of endometrioid-type glands and endometrioid-type stroma. However, small nodules or plaques of endometrioid-type stroma without glands have been noticed by the authors in repeated peritoneal biopsies performed for suspected endometriosis. These are often, but not always, accompanied by typical endometriosis with glands. This form of endometriosis has been previously referred to as stromal or micronodular stromal endometriosis. However, there has been little reference to this condition in the literature. METHODS: In this study, there was a review of a large series (n = 274) of peritoneal biopsies with a diagnosis of endometriosis with a view to ascertaining the frequency of stromal endometriosis. RESULTS: Stromal endometriosis, characterised histologically by small microscopic nodules or plaques of endometrioid-type stroma, sometimes with a whorled pattern and prominent vascularity and erythrocyte extravasation, was identified in 44.9% of the biopsies. In 6.6% of the biopsies, stromal endometriosis occurred without typical endometriosis. The foci of stromal endometriosis usually had a superficial location just beneath the mesothelial surface or protruding above this. Associated histological features present in some cases included reactive mesothelial proliferation, inflammation, giant cell or granuloma formation, haemosiderin pigment deposition, microcalcification and decidualisation and myxoid change. CONCLUSIONS: Stromal endometriosis, usually in the form of superficial nodules or plaques, is a relatively common form of endometriosis which typically occurs in association with typical endometriosis but occasionally on its own. Pathologists should be aware of the existence of this form of endometriosis, the morphological features of which may be subtle. The typical location, intimately associated with surface mesothelium, may suggest that stromal endometriosis derives from mesothelial or submesothelial cells via a metaplastic process.

Combined actinomycotic and pseudoactinomycotic radiate granules in the female genital tract: description of a series of cases.

BACKGROUND: Both actinomycotic granules and pseudoactinomycotic radiate granules (PAMRAGs) occur in the female genital tract, most commonly in the endometrium. It is important to distinguish between these since the former may result in pelvic inflammatory disease and require antibiotic treatment while the latter is non-infectious and does not require specific treatment. AIMS: To investigate the coexistence of actinomyces-like organisms and PAMRAGs in the same granules, and describe the presence of PAMRAGs in the cervix and the vulva. METHODS: Six cases with actinomyces-like organisms and PAMRAGs in the same granules (four in the endometrium, one in a tubo-ovarian abscess, and one in both the endometrium and a tubo-ovarian abscess) are reported as well as seven examples of PAMRAGs in the cervix and one in a vulval abscess. RESULTS: The combined granules consisted of central basophilic Gram and silver positive filamentous organisms consistent with actinomyces surrounded by radiating eosinophilic club-like formations which were Gram and silver negative, the latter consistent with PAMRAGs. The PAMRAGs in the cervix and vulva consisted entirely of Gram and silver negative radiating eosinophilic club-like formations. CONCLUSIONS: Although actinomycotic granules and PAMRAGs are distinct lesions which should be distinguished for patient management, they may coexist in the same granules. It is likely in such cases that the PAMRAGs form around the bacterial colonies which act as a nidus. The presence of radiating eosinophilic club-like formations characteristic of PAMRAGs does not preclude the presence of actinomyces. Careful morphological examination plus supportive Gram and silver stains, if necessary, allows the diagnosis of these combined granules. PAMRAGs also occur in the cervix, where it is likely that they form secondary to encrustation of inspissated mucus, and in the vulva.

Toward a measure of caregiver satisfaction with hospice social services.

An evaluation of caregiver satisfaction with social services in a large hospice in a major southeastern city was conducted utilizing an instrument developed for this study. The usual processes for developing an instrument were followed, resulting in a survey questionnaire which was useful in testing the degree of satisfaction of caregivers with the hospice's social services. Results indicated that most caregivers were very satisfied with hospice social services. The development of such an instrument could aid others in the field in evaluating caregiver satisfaction with hospice services.