Tracer-Encapsulated Solid Pellet (TESPEL) injection system for Wendelstein 7-X.

Impurity confinement in fusion plasmas is mainly determined by transport mechanisms in the core region. For the Wendelstein 7-X stellarator, its island divertor is expected to screen effectively external impurity sources in the scrape-off layer at higher densities. However, the unique feature of Tracer-Encapsulated Solid Pellet (TESPEL) injection, releasing impurities at a well-localized radial position directly in the core plasma, enables investigating such transport mechanisms. This paper reports on the detailed design of a completely new TESPEL injection system, which has been designed by the National Institute for Fusion Science, Toki, Japan, and is currently being installed at Max-Planck-Institut für Plasmaphysik, Greifswald, Germany, for the Wendelstein 7-X. This injector consists of a storage and injection unit, attached to a system of guiding tubes which run through 3 successive differential pumping stages. A light-gate system and an optical observation system are used to determine the location of the deposited tracers. Laboratory tests carried out by shooting TESPELs onto a sample foil showed good performance after careful realignment of the guiding tubes.

Plasma impurities observed by a pulse height analysis diagnostic during the divertor campaign of the Wendelstein 7-X stellarator.

The paper reports on the optimization process of the soft X-ray pulse height analyzer installed on the Wendelstein 7-X (W7-X) stellarator. It is a 3-channel system that records X-ray spectra in the range from 0.6 to 19.6 keV. X-ray spectra, with a temporal and spatial resolution of 100 ms and 2.5 cm (depending on selected slit sizes), respectively, are line integrated along a line-of-sight that crosses near to the plasma center. In the second W7-X operation phase with a carbon test divertor unit, light impurities, e.g., carbon and oxygen, were observed as well as mid- to high-Z elements, e.g., sulfur, chlorine, chromium, manganese, iron, and nickel. In addition, X-ray lines from several tracer elements have been observed after the laser blow-off injection of different impurities, e.g., silicon, titanium, and iron, and during discharges with prefill or a gas puff of neon or argon. These measurements were achieved by optimizing light absorber-foil selection, which defines the detected energy range, and remotely controlled pinhole size, which defines photon flux. The identification of X-ray lines was confirmed by other spectroscopic diagnostics, e.g., by the High-Efficiency XUV Overview Spectrometer, HEXOS, and high-resolution X-ray imaging spectrometer, HR-XIS.

Observation of Oscillatory Radial Electric Field Relaxation in a Helical Plasma.

Measurements of the relaxation of a zonal electrostatic potential perturbation in a nonaxisymmetric magnetically confined plasma are presented. A sudden perturbation of the plasma equilibrium is induced by the injection of a cryogenic hydrogen pellet in the TJ-II stellarator, which is observed to be followed by a damped oscillation in the electrostatic potential. The waveform of the relaxation is consistent with theoretical calculations of zonal potential relaxation in a nonaxisymmetric magnetic geometry. The turbulent transport properties of a magnetic confinement configuration are expected to depend on the features of the collisionless damping of zonal flows, of which the present Letter is the first direct observation.

Tracer-Encapsulated Solid Pellet (TESPEL) injection system for the TJ-II stellarator.

A tracer-encapsulated solid pellet (TESPEL) injection system for the TJ-II stellarator was recently developed. In order to reduce the time and cost for the development, we combined a TESPEL injector provided by National Institute for Fusion Science with an existing TJ-II cryogenic pellet injection system. Consequently, the TESPEL injection into the TJ-II plasma was successfully achieved, which was confirmed by several pellet diagnostics including a normal-incidence spectrometer for monitoring a tracer impurity behavior.

Upgrade of the neutral particle analyzers for the TJ-II stellarator.

The TJ-II stellarator, a magnetically confined plasma device, is equipped with a broad range of diagnostics for plasma characterization. These include 4 neutral particle analyzers (NPAs), consisting of two Acord-12's, to perform poloidal measurements, plus a compact NPA, and an Acord-24, these in tangential viewing positions. The Acord-12's were originally equipped with two rows of 6 channels each, one for hydrogen neutrals and the other for deuterium neutrals but were changed to a single row of 12 detectors for hydrogen, the principal working gas in TJ-II. With this upgrade the resultant improved energy resolution spectrum has allowed more reliable ion temperature estimates to be obtained. Here we present the upgrades undertaken and present results to demonstrate the improved performance of this diagnostic.

Impurity temperature correction factors for the transmission grating spectrometer in the TJ-II stellarator.

Impurity ion temperature and velocity profiles are obtained across plasmas in the TJ-II stellarator by performing charge-exchange recombination spectroscopy with a diagnostic neutral beam injector. For this, a tridirectional (toroidal plus two poloidal opposing views) multichannel spectroscopic diagnostic, incorporating 12-way fiber arrays, a compact f/1.8 spectrograph, and a back-illuminated CCD, permits Doppler line shifts and widths (of the C VI line at 529.05 nm) to be determined with 1-2 cm spatial resolution. For good photon counting statistics under Li-coated wall conditions, 600 µm diameter fibers collect and transmit light to curved 100 µm wide input slits. When calibrated with a neon pencil lamp this entrance slit width results in a non-Gaussian instrumental function that, if not handled correctly, can result in systematically underestimated impurity temperatures. Here we develop and present correction factors for this effect for a range of conditions.

The response of a radiation resistant ceramic scintillator (Al2O3:Cr) to low energy ions (0-60 keV).

This work extends a previous study on ionoluminescence of a radiation-hard ceramic scintillator, Al(2)O(3):Cr, to ions accelerated to keV energies [K. J. McCarthy et al., J. Nucl. Mater. 321, 78 (2003)]. It is motivated by the identification of this material as a promising candidate for use in the fast-ion-loss detector for ITER [for the range of thermal (low energy) and suprathermal ions]. In the paper we quantify and compare its ionoluminescence with that of some common luminescent materials (YAG:Ce and ruby) when irradiated by H(+) ions accelerated to < or = 60 keV using a purpose built laboratory setup. Next, studies are made on the ceramic to quantify its response as a function of incident ion mass, i.e., to He(+). For this, the absolute luminosities of the material are estimated in terms of the number of photons emitted per incident ion as a function of energy. Moreover, the radiation hardness and postirradiation recovery of the ceramic are investigated. Finally, from the studies it can be concluded that the ceramic ruby is a good candidate for detecting low energy ions as long as its temporal response (approximately several milliseconds) is not a constraint for specific ion measurements.

A compact flexible pellet injector for the TJ-II stellarator.

A compact pellet injector is being built for the TJ-II stellarator. It is an upgraded version of the "pellet injector in a suitcase" developed at Oak Ridge National Laboratory and installed on the Madison Symmetric Torus where it continues to be used in many plasma experiments. The design aim is to provide maximum flexibility at minimal cost, while allowing for future upgrades. It is a four-barrel system equipped with a cryogenic refrigerator for in situ hydrogen pellet formation, a combined mechanical punch/propellant valve system, pellet diagnostics, and an injection line, destined for use as an active diagnostic and for fueling. In order to fulfill both objectives it will be sufficiently flexible to permit pellets, with diameters from 0.4 to 1 mm, to be fabricated and accelerated to velocities from 150 to approximately 1000 m s(-1).

Leprecan distribution in the developing and adult kidney.

The temporal and spatial deposition of extracellular matrix proteins is critical for nephrogenesis and glomerular maturation. We previously characterized leprecan as a novel chondroitin sulfate proteoglycan which has been recently shown to have prolyl hydroxylase activity. In this study, we examine the distribution of leprecan during nephrogenesis and after a hypertrophic stimulus to the adult kidney. During development, leprecan was localized to mesenchymal aggregates, early comma- and S-phase structures as determined by immunohistochemistry and in situ hybridization. Leprecan mRNA was increased in cells around the vascular cleft of the S- and comma-phase glomeruli. Expression was found in podocytes, mesangial cells, and parietal epithelial cells of loop-phase glomeruli. Leprecan mRNA was substantially decreased in the glomeruli of the adult kidney compared to the developing kidney with a uniform distribution between the glomeruli and the tubules. Within adult glomeruli, leprecan was found in the mesangium mesangial matrix, podocytes, and in Bowman's capsule. In response to glomerular hypertrophy, produced by unilateral nephrectomy, leprecan synthesis was increased in the adult kidney. We suggest that the regulated expression of leprecan during glomerular development or hypertrophy coupled with its reported prolyl hydroxylase activity plays a role during basement membrane assembly.

The growth of chondrocytes into a fibronectin-coated biodegradable scaffold.

Porous scaffolds made from a biodegradable copolymer of trimethylene carbonate and glycolide were evaluated for tissue-engineered medical products. We examined the scaffold coated with cell adhesion protein and fibronectin and cultured under a dynamic mixing condition to enhance the growth of chondrocytes. Our hypothesis was that the combination of coating and dynamic mixing would be beneficial to the viability of the chondrocytic cells. Fibronectin was selected as the model protein because of its availability and routine assaying methods. Sterile samples of scaffolds of about 1 mm in thickness were coated with fibronectin at 37 degrees C for 1.5 h. Four groups of scaffolds were used: uncoated static or dynamic, and coated static or dynamic. Scaffold samples were placed in either a Petri dish or a spinner flask (static vs. dynamic groups) after inoculation with rat chondrocytes of an initial cell density of 1.29 x 10(5) cell/mL. After 7, 14, 21, and 28 days, each sample was fixed, embedded, and sectioned at 5 micro thickness. The sections were double-label immunostained using antibodies against cellular fibronectin synthesized by adherent cells as a measure of cell viability. A Hoechst 33258 nuclear stain was used to measure the number of cells attached to the scaffold at each time interval. The slides were examined using a fluorescence microscope to determine the cell ingrowth. At least 25 fields/treatment group (except the 7 day group) were measured. The data showed that cell in-growths into the porous scaffolds were higher at all time periods for the coated dynamic group than those for the other three groups.

Troglitazone halts diabetic glomerulosclerosis by blockade of mesangial expansion.

BACKGROUND: Renal complications of long-term, poorly controlled type 2 diabetes mellitus include glomerulosclerosis and interstitial fibrosis. The onset and progression of these complications are influenced by underlying pathophysiologies such as hyperglycemia, hypertriglyceridemia, and hypercholesterolemia. Troglitazone, a thiazolidinedione, has been shown to ameliorate these metabolic defects. However, it was not known whether therapeutic intervention with troglitazone would prevent the onset and progression of glomerulosclerosis. METHODS: Sixty male ZDF/Gmitrade mark rats and 30 age-matched Zucker lean rats were in the study. The ZDF/Gmitrade mark rats were divided into two groups, one in which blood glucose levels were uncontrolled (30 animals) and another (30) in which blood glucose was controlled via dietary administration of troglitazone. Ten animals from each group were sacrificed at one, three, and six months into the study. The kidneys were harvested and processed for immunostaining with BM-CSPG, a marker for mesangial matrix. Images of 200 glomeruli per animal were captured using digital imaging microscopy, and the index of mesangial expansion (total area mesangium/total area of tuft) per glomerular section was measured. RESULTS: The administration of troglitazone ameliorated the metabolic defects associated with type 2 diabetes mellitus. Moreover, the glomeruli from tissue sections of animals given troglitazone showed no mesangial expansion when compared with normoglycemic control animals, whereas the uncontrolled diabetic animals showed significant mesangial expansion at all time intervals. CONCLUSIONS: Therapeutic intervention with the thiazolidinedione troglitazone halts the early onset and progression of mesangial expansion in the ZDF/Gmitrade mark rat, preventing the development of glomerulosclerosis in this animal model of type 2 diabetes mellitus.

Gap junctions in human synovial cells and tissue.

Our objective was to establish the existence of intercellular communication through gap junctions in synovial lining cells and in primary and passaged cultures of human synovial cells. Communication between cells was assessed using the nystatin perforated-patch method, fluorescent dye transfer, immunochemistry, transmission electron microscopy, and immunoblotting. Functional gap junctions were observed in primary and passaged cultures and were based on measurements of the transient current response to a step voltage. The average resistance between cells in small aggregates was 300 +/- 150 MOmega. Gap junctions were also observed between synovial lining cells in tissue explants; the size of the cell network in synovial tissue was estimated to be greater than 40 cells. Intercellular communication between cultured cells and between synovial lining cells was confirmed by dye injection. Punctate fluorescent regions were seen along intercellular contacts between cultured cells and in synovial membranes in cells and tissue immunostained for connexin43. The presence of the protein was verified in immunoblots. Regular 2-nm intermembrane gap separations characteristic of gap junctions were seen in transmission electron micrographs of synovial biopsies. The results showed that formation of gap-junction channels capable of mediating ionic and molecular communication was a regular feature of synovial cells, both in tissue and in cultured cells. The gap junctions contained connexin43 protein and perhaps other proteins. The physiological purpose of gap junctions in synovial cells is unknown, but it is reasonable to anticipate that intercellular communication serves some presently unrecognized function.

Basement membrane chondroitin sulfate proteoglycan and vascularization of the developing mammalian limb bud.

We used immunocytochemistry to study the basement membrane-chondroitin sulfate proteoglycan (BM-CSPG) distribution in mammalian limb bud and its relationship to and possible role in limb development. Anti-BM-CSPG immunostaining was examined in the developing limb buds of 24 Sprague-Dawley rats at embryonic days 12 to 14 and 19. BM-CSPG immunostaining was present in 3 regions. The first region was located peripherally in the limb bud ectodermal basement membrane (BM) that separates ectoderm from mesoderm and was present at all embryonic stages examined. The second region was in the mesenchymal extracellular matrix independent of the vascular system. This staining pattern was diffuse, granular, and often homogeneous, except for clustering adjacent to developing vessels, and was observed distally in the limb bud. In the mesenchymal extracellular matrix adjacent to the distal BM this staining pattern formed fibrils that were perpendicular and connected to the limb bud BM and extended into the underlying mesenchyme. The third region was localized to the BM of developing blood vessels of the limb bud. Blood vessel staining allowed analysis of limb bud vessel formation. The early developing blood vessels at the proximal limb bud were organized differently from those located distally. Large central vessels were present proximally, whereas a rich plexus of smaller vascular channels was present at the distal margin. A subectodermal avascular zone was observed at the margin of the limb bud, except beneath the apical ectodermal ridge where immunostained blood vessels extended from the distal vascular plexus toward the apical ectodermal ridge. The formation of central larger vessels occurs proximally, whereas formation of peripheral smaller vessels seems to take place locally and distally under the influence of the apical ectodermal ridge. BM-CSPG plays an important role in blood vessel formation and mammalian limb bud development. (J Hand Surg 2000; 25A:150-158.

A study of the response of Y3Al5O12:Ce phosphor powder screens in the vacuum ultraviolet and soft X-ray regions using synchrotron radiation.

Phosphor screens find application in many fields because of their ability to convert incident radiation to wavelengths that are readily measured by modern detectors. While the response of such screens in the X-ray region has been widely studied, much work still remains to be done regarding their response in the vacuum ultraviolet and soft X-ray regions, where the response is predicted to be non-linear owing to the presence of elemental absorption edges. Here, an experiment using synchrotron radiation to determine the response of thin Y(3)Al(5)O(12):Ce (1-21 mg cm(-2)) and Y(2)O(3):Eu (2.64 mg cm(-2)) powder phosphor screens in the spectral range 20-900 A (13.8-620 eV) is reported. Also, a custom-built camera is described which permits simultaneous collection of the forward- and backward-emitted light and that enables measurements to be made at various positions across the screens and at several screen/incident beam angles. Finally, features in the response spectra are identified, and efficiencies across the spectral range indicated for different screen thicknesses and operating modes are plotted, before a curve of the intrinsic radiant efficiency of Y(3)Al(5)O(12):Ce is produced. The results are discussed in the context of other measurements.

Molecular characterization of a novel basement membrane-associated proteoglycan, leprecan.

A monoclonal antibody was used in early studies to identify a novel chondroitin sulfate proteoglycan, secreted by L-2 cells, the core protein of which was approximately 100 kDa. To characterize this proteoglycan core protein at the molecular level, an L-2 cell cDNA library was probed by expression screening and solution hybridization. Northern blot analysis assigned transcript size to approximately 3.1 kilobases and, after contig assembly, the coding region of the mRNA corresponded to 2.18 kilobases. Immunoassays were performed to confirm the identity of this sequence, using a polyclonal antibody raised against an expressed fusion protein encoded by sequence representing the carboxyl half of the molecule. The antibody recognized the core protein in Western blots after prior digestion of the intact proteoglycan with chondroitinase ABC. Immunostaining tissue sections with the same antibody localized the proteoglycan to basement membranes, and expression of the entire sequence in Chinese hamster ovary K-1 cells showed that the protein encoded by the sequence secreted as a chondroitin sulfate proteoglycan. The core protein not only has motifs permitting glycosylation as a proteoglycan, but also possesses the endoplasmic reticulum retrieval signal, KDEL, which suggests that, in addition to its role as a basement membrane component, it may also participate in the secretory pathway of cells.

Peer reviewed: environmental forensics unraveling site liability.

An interdisciplinary analytical approach can unravel environmental liability at contaminated sites.

Morphogenesis of the glomerular filter: the synchronous assembly and maturation of two distinct extracellular matrices.

The morphogenesis of the glomerular filtration apparatus during pre- and postnatal development in the rodent involves the coordinated assembly of two closely apposed but morphologically different extracellular matrices, the glomerular capillary basement membrane and the mesangial matrix. The cellular origin of these matrices is known to be distinct and complex; however, the mechanisms by which these matrices are assembled during morphogenesis are not entirely understood. It has been shown that in the earliest stages of glomerular morphogenesis the nascent glomerular basement membrane exists as a four-layered structure, the product of both the visceral epithelium and capillary endothelium. During the latter stages of glomerular development, the quadrilaminar structure becomes a trilaminar basement membrane, the event thought to occur by fusion of closely apposed basement membrane layers. In subsequent stages of maturation and throughout the life of the animal, the visceral epithelial cells, which line the periphery of the glomerular capillary, are the primary source of newly synthesized basement membrane material. The mesangial matrix, which lacks the specific organization of a basement membrane, first occurs in the developing glomerulus as a diffuse matrix central to the developing glomerular capillaries. During glomerular maturation the mesangial matrix undergoes a compaction/arborization coincident with the ramification of the vascular histoarchitecture of the glomerular tuft. Recent advances in the cell biology of basement membrane now demonstrate that there is a divergence in isoforms of the molecules that comprise the glomerular capillary basement membrane and mesangial matrices during development, possibly coincidental with functional specialization during the process of glomerular maturation.

A human resource planning model for hospital/medical technologists: an analytic hierarchy process approach.

This paper deals with the development of a human resource planning (HRP) model for hospital laboratory personnel. External and organizational factors impacting the demand and supply of clinical laboratory personnel in an urban academic health center are identified by a Delphi process. These factors are structured into a hierarchy for the application of the Analytic Hierarchy Process (AHP). Computer software, Expert Choice, was used in model hierarchy development and judgmental elicitation process. The model result can be applicable to eliciting the perceptions, insights, and understanding of health-care decision-makers for strategic human resource planning.

The X-Ray CCDs Developed for the Joint European X-Ray Telescope.

The charge coupled devices (CCDs) developed for the Joint European X-ray Telescope (JET-X) are described in detail. A history of the development program and device performance is given. We present results from a comprehensive study to characterize the x-ray response of the flight model focal plane detectors. The goal of the program is to calibrate the efficiency, energy resolution, gain, etc. down to a precision of ~1%. Final calibration data sets will be based on combinations of measurements and calculations. For example, the CCD quantum efficiency will be composed of discrete line measurements made at the University of Leicester test facility and calculation and synchrotron measurements from the Daresbury Synchrotron Radiation Source (SRS). The absolute normalizations will be provided by x-ray long beam pipe measurements at the Max Planck Institut für Extraterrestrische Physik (MPE) Panter test facility in Munich. Using the available data, it is shown that it is possible to calibrate the quantum efficiency, the FWHM energy resolution, and the system gain of the flight devices to better than 1%.

Targeting of transforming growth factor-alpha expression to pituitary lactotrophs in transgenic mice results in selective lactotroph proliferation and adenomas.

The PRL-secreting cells of the pituitary gland normally express transforming growth factor-alpha (TGF alpha). To determine the effect of increasing TGF alpha expression in the pituitary, a transgenic mouse model was created in which overexpression of human TGF alpha was directed to the pituitary lactotrophs using the rat PRL promoter. Of the four gene-positive mouse lines, two expressed the messenger RNA corresponding to the transgenic in the pituitary glands. However, in both these lines, expression could only be detected in the female animals. Expression of the transgenic could be detected as early as 1 month of age, but no pathology or developmental abnormalities were detected until the animals reached 6 months, at which time, hyperplasia of the lactotrophs. By the age of 12 months, all of the homozygous transgenic females had developed pituitary adenomas that were immunopositive for PRL. The other hormone-producing cells of the pituitary showed no obvious pathology. The male transgenics developed neither hyperplasia nor adenomas, nor did the gene-positive transgenic lines that did not express the transgene. In no case was an aggressive pituitary tumor seen. This transgenic mouse model indicates that TGF alpha overexpression by lactotrophs stimulates the growth of these pituitary cells. Furthermore, TGF alpha has a highly localized action in the pituitary gland, resulting only in lactotroph hyperplasia and prolactinomas. These observations suggest that TGF alpha might play a role in the development of prolactinomas.