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Previously, we have reported that ginsenoside Rg3 has typical activities for neuroprotection and Aβ42 clearance by modulating microglia. In this study, we determined the pivotal role of ginsenoside Rg3 in microglia and neuronal cells. In human microglia, Rg3 and its stereoisomers significantly restored inflammatory M1 to normal M0 state and promoted M2 activation by up-regulating acute cytokines such as interleukin-10 and Arginase 1. Moreover, scavenger receptor type A (SRA) was significantly elevated in the presence of ginsenoside Rg3 and 20(S)-Rg3. This indicated that ginsenoside Rg3 could play a crucial role in Aβ uptake and clearance under activated M2 state. We also observed that soluble amyloid precursor protein-alpha (sAPPα) and ADAM10 levels were increased in APP swe-transfected Nuro-2a neuronal cells, whereas sAPPβ was not processed, suggesting that ginsenoside Rg3 was involved in non-amyloidogenic processing. In immunocytochemistry, SRA and a disintegrin and metalloproteinase 10 (desintegrin and metalloproteinase-containing protein 10, ADAM10) were coincidently upregulated in the presence of ginsenoside Rg3 and its stereoisomers compared to those in normal control. Taken together, these results suggested that ginsenoside Rg3 could boost acute activation of microglia, promote Aβ uptake, and elevate the sAPPα processing under activated M2 state. Although in vivo studies need to be performed, it is certain that ginsenoside Rg3 is highly involved in ameliorating the pathogenesis of neurodegeneration and can be a promising candidate for treating Alzheimer's disease as a new therapeutic intervention.

Gamma-rays are an important mutagenic agent that can induce new, useful genetic variations in plants. However, γ-irradiation can also cause damage that negatively affects the use of such mutagens in plant breeding. The aim of the present study was to investigate the effects and damage caused by γ-radiation in a Cymbidium hybrid, RB001. The relative growth rate of protocorm-like bodies (PLBs) was reduced by 50% at a γ-ray dose of approximately 40 Gy. Malondialdehyde concentrations increased significantly with increasing radiation dose. However, almost no difference was observed between untreated control PLBs and PLBs treated with 200 Gy 8 weeks after γ-irradiation. The activities of several antioxidant defence enzymes increased gradually with increasing γ-ray dose, 24 h after irradiation. These enzymes showed different responses between 1 and 4 weeks, but no difference 8 weeks after irradiation. The ‘comet assay’ and flow cytometry were performed. Clear differences in radiation-induced damage were ...

The paper presents methodologies and results concerning one- and two-dimensional numerical modeling of radio frequency oscillations in a coaxial transmission line fed with a short pulse of electric current. The line is partially filled with a ferrite material, magnetized longitudinally close to saturation. The 2D model has permitted analyzing, for the first time in the art, the spatial structure and dynamics of the wave field within the radially non-uniform cross-section planes of the non-linear and dispersive guiding structure. This opens ways for optimizing size parameters of the line and the extent to which it is filled with the ferromagnetic material, thus increasing the line’s electric strength and intensity of the r.f. oscillations.

Comparative genomic hybridization (CGH) is a powerful tool used to analyze changes in copy number, polymorphisms, and structural variations in the genome. Gene copy number variation (CNV) is a common form of natural diversity in the genome, which can create new genes and alter gene structure. Thus, CNVs may influence phenotypic variation and gene expression. In this study, to detect CNVs, we irradiated rice seeds with gamma rays (300 Gy) and selected two dwarf mutagenized plants, GA-III-189 and -1052, in the M3 generation. These plants were subjected to CGH analysis using Agilent's RICE CGH array. Most of the CNVs identified were less than 10 kb in length. We detected 90 amplified and 18 deleted regions in GA-III-189, and 99 amplified and 11 deleted regions in GA-III-1052. Of note, CNVs were located on chromosome 12 in both GA-III-189 and -1052, which contained 39 commonly amplified regions in 29 genes. The commonly amplified genes included six genes encoding F-box domain-containing proteins. Alterations in these F-box domain-containing genes were confirmed by quantitative RT-PCR. Integration of CGH and gene expression data identified copy number aberrations and novel genes potentially involved in the dwarf phenotype. These CGH and gene expression data may be useful for uncovering the mechanisms underlying the dwarf phenotype.

Steady-state visual evoked potential (SSVEP) has been widely used in electroencephalogram (EEG)-based brain-computer interfaces (BCIs) due to its high information transfer rate (ITR) and short training time. Current methods usually measure SSVEP from electrodes on the scalp, which is an uncomfortable and time-consuming method. Furthermore, most research relies on expensive and non-portable EEG devices. To utilise BCIs in daily life, however, these are critical issues to address. Hence, a wearable EEG device for in-ear SSVEP detection is proposed. The system is 40 × 21 × 10.5 mm 3 and weighs 14.2 g, thus being light weight and wearable. Moreover, the system has a noise level of 0.11 μVrms, which is comparable with commercial EEG systems. Six subjects participated in an offline BCI experiment that consisted of six visual targets using the developed in-the-ear EEG system. The results showed a highest ITR of 11.03±4.18bits/min with an accuracy of 79.9 ± 13.1%, and the experiments demonstrated that the system can be utilised for unobtrusive monitoring of SSVEP in BCI applications.

There has been a huge acceleration in our technical ability to detect variation in the human genome in recent years, and there has been a corresponding effort in clinical diagnostic laboratories to take advantage of this progress for the benefit of patients. There has, however, not been an equivalent increase in our understanding of human genetics and disease, not for lack of effort but due to the far greater complexity of understanding variation than the difficulties of detecting it. This chapter describes how software tools can be used to target clinical genetic diagnostic testing in order to exploit technical and scientific advances both efficiently and cost-effectively, while maximizing clinical utility.

This study evaluated the chemical and genetic diversity of high-seed-yield sorghum germplasms from Korea, the United States, and South Africa. We identified significant differences in the chemical contents of whole plants at the heading stage in all cultivars, including differences in crude protein, fat, fiber, ash, neutral detergent fiber, acid detergent fiber, mineral, and fatty acid contents. Our results suggest that Banwoldang is the most appropriate cultivar for roughage because of its high protein yield. We identified significant differences in the tannin, flavonoid, amylose, mineral, crude fat, fatty acid, and 3-deoxyanthocyanin contents in the whole grain from all cultivars, but not in the mineral or crude fat contents. Tannin levels were generally low. IS645 contained the highest levels of flavonoids and linolenic acid compounds, and Moktak had the highest amylose and deoxyanthocyanidin content in the grain. To assess genetic diversity, we used 10 simple sequence repeat (SSR) primer sets to identify 38 alleles with 3-8 alleles per locus. Based on phylogenetic analysis of the SSR markers, the sorghum cultivars were divided into three major groups. Comparison of clusters based on chemical compositions with those based on SSRs showed that the groups formed by the three native Korean cultivars clustered similarly in molecular dendrograms. Association analysis was conducted for the 10 SSR marker; 48 chemical and growth traits were present for two marker traits (seed color and whole plant fatty acid content) with significant marker-trait associations. These markers could be used to select sorghum cultivars for breeding programs.

Under certain circumstances, transposable elements (TE) can create or reverse mutations and alter the genome size of a cell. Sorghum (Sorghum bicolor L.) is promising for plant transposon tagging due to its small genome size and its low content of repetitive DNA. We developed a marker system based on targeted region amplification polymorphisms (TE-TRAP) that uses the terminal inverted repeats (TIRs) of transposons. A total of 3816 class 2 transposons belonging to the PIF/Harbinger family were identified from the whole sorghum genome that produced five primers, including eight types of TIRs. To define the applicability and utilization of TE-TRAP, we used 21 individuals that had been bred after ɤ-ray irradiation. In total, 31 TE-TRAP, 16 TD, and 21 AFLP primer combinations generated 1133, 223, and 555 amplicons, respectively. The percent polymorphic marker was 62.8, 51.1, and 59.3% for the TE-TRAP, TD, and AFLP markers, respectively. Phylogenetic and principal component analyses revealed that TE-TRAP divided the 21 individuals into three groups. Analysis of molecular variance suggested that TE-TRAP had a higher level of genetic diversity than the other two marker systems. After verifying the efficiency of TE-TRAP, 189 sorghum individuals were used to investigate the associations between the markers and the ɤ-ray doses. Two significant associations were found among the polymorphic markers. This TE-based method provides a useful marker resource for mutation breeding research.

Filamentary structures are observed in the scrape-off layer of the National Spherical Torus Experiment during ELMs. While the primary filaments correspond to a direct result of the ELM event, the ‘secondary’ filaments which occur generally later but still within 1 ms of the ELM onset are observed to have the same characteristics as inter-ELM filaments (or blobs): poloidal auto-correlation lengths of ∼4 cm, broadband frequency and poloidal wave number spectra and radial velocities of 1–2 km/s. At the same time, no MHD modes are observed during the phase in which secondary filaments are present.

The dependence of various SOL widths on the line-averaged density ({ovr n}{sub e}) and plasma current (l{sub p}) for the quiescent H-mode plasmas with Type-V ELMs in the National Spherical Torus Experiment (NSTX) was investigated. It is found that the heat flux SOL width ({lambda}{sub q}), measured by the IR camera, is virtually insensitive to {ovr n}{sub e} and has a strong negative dependence on l{sub p}. This insensitivity of {lambda}{sub q} to {ovr n}{sub e} is consistent with the scaling law from JET H-mode plasmas that shows a very weak dependence on the upstream density. The electron temperature, ion saturation current density, electron density, and electron pressure decay lengths ({lambda}{sub Te}, {lambda}{sub jsat}, {lambda}{sub ne}, and {lambda}{sub pe}, respectively) measured by the probe showed that {lambda}{sub Te} and {lambda}{sub jsat} have strong negative dependence on l{sub p}, whereas {lambda}{sub ne} and {lambda}{sub pe} revealed only a little or no dependence. The dependence of {lambda}{sub Te} on l{sub p} is consistent with the scaling law in the literature while {lambda}{sub ne} and {lambda}{sub pe} dependence shows a different trend.

A new data-set of outboard mid-plane scrape-off layer (SOL) heat flux widths, Δh, has been constructed for L-mode plasmas in the MAST spherical tokamak (ST). The scaling with key plasma parameters such as density, toroidal magnetic field, parallel connection length in the SOL and surface heat flux at the separatrix is investigated. An empirical scaling is developed for the Δh data-set, which exhibits a strong positive dependence on both the connection length (or edge safety factor) and density and weak or moderate inverse dependences on the surface heat flux and magnetic field, respectively. The empirical scaling is compared with earlier results for a range of tokamaks with conventional geometry, which show weaker dependence on the density and edge safety factor. Importantly, however, the weak negative dependence on the surface heat flux (and thus heating power) is common in both conventional and ST geometries. The experimental data are also used to test a number of dimensionally correct Δh scalings developed from theoretical models for perpendicular transport in the SOL coupled with classical transport parallel to the magnetic field. A scaling based on perpendicular transport driven by resistive MHD interchange provides the best fit, although several models are close. A subset of the better fitting theoretical scalings are used to extrapolate for Δh in one design for a future burning ST machine and finally to predict the peak heat loading on the outboard divertor target plate.

Low aspect ratio plasmas in devices such as the mega ampere spherical tokamak (MAST) are characterized by strong toroidicity, strong shaping and self fields, low magnetic field, high beta, large plasma flow and high intrinsic E × B flow shear. These characteristics have important effects on plasma behaviour, provide a stringent test of theories and scaling laws and offer new insight into underlying physical processes, often through the amplification of effects present in conventional tokamaks (e.g. impact of fuelling source and magnetic geometry on H-mode access). The enhancement of neoclassical effects makes MAST ideal for the study of particle pinch processes and neoclassical resistivity corrections, which can be assessed with unique accuracy. MAST data have an important influence on scaling laws for confinement and H-mode threshold power, exerting strong leverage on the form of these scaling laws (e.g. scaling with aspect ratio, beta, magnetic field, etc). The high intrinsic flow shear is conducive to transport barrier formation by turbulence suppression. Internal transport barriers are readily formed in MAST with both co- and counter-NBI, and electron and ion thermal diffusivities have been reduced to the ion neoclassical level. The strong variation in toroidal field (~ × 5 in MAST) between the inboard and outboard plasma edges, provides a useful test of edge models prompting, for example, a comparison of inboard and outboard scrape-off-layer transport to highlight magnetic field effects. Low aspect ratio plasmas are also an ideal testing ground for plasma instabilities, such as neoclassical tearing modes, edge localized modes (ELMs) and Alfven eigenmodes, which are readily generated due to the supra-Alfvenic ion population. Examples of how MAST is providing new insights into such instabilities (e.g. ELM structure) are described.

The outboard mid-plane values of electron density (ne) and temperature (Te) in the scrape-off-layer (SOL) of MAST are derived from target Langmuir probe measurements using OSM2-EIRENE and also using a simple two-point model. The values are compared with mid-plane measurements of ne and Te from a reciprocating probe and a Thomson scattering system for Ohmic, L- and H-modes single-null divertor (SND) discharges. The cross-field heat (χ⊥) diffusion coefficient at the low field side of SND discharges is derived both using the OSM2-EIRENE model and a two-point model coupled with a simple theory. The results are found to be similar within the errors. Typically χ⊥ values are found to lie in the range 0.5–2.0 m2 s−1 for L-mode and 0.1–0.5 m2 s−1 for H-mode. A comparison is made of the transport coefficients derived at the low and high field sides for a set of connected double-null discharges. These results are used to make preliminary observations of the effect of magnetic fields on SOL transport in MAST.

Integrated modelling of important plasma physics issues related to the design of a steady-state spherical tokamak (ST) fusion power plant is described. The key is a steady-state current drive, and 92% of this is provided by a combination of bootstrap and diamagnetic currents, both of which have a substantial toroidal component in a ST. The remaining current is to be provided by either neutral beam injection or radio-frequency waves, and various schemes for providing this are discussed and quantified. The desire to achieve a high bootstrap current drives the design to high plasma pressure, ? (normalized to the magnetic field pressure), and high elongation. Both these requirements have implications for ideal magneto-hydrodynamic instability which are discussed. Confinement is addressed both through comparison with the recent scaling laws developed from the conventional tokamak database and self-consistent one-dimensional modelling of the transport processes. This modelling shows that the power required for the current drive (~50?MW) is sufficient to heat the plasma to a regime where more than 3?GW of fusion power is produced, taking into account the dilution due to He ash and prompt ?-particle losses, which are small. A preliminary study of the micro-instabilities, which may be responsible for the turbulent transport is provided. Given assumptions about the particle confinement, we make estimates of the fuelling requirements to maintain the steady state. Finally, the power loading due to the exhaust is derived using theory-based scalings for the scrape-off layer width.

Edge localized mode (ELM) characteristics in a large spherical tokamak (ST) with significant auxiliary heating are explored. High confinement is achieved in mega ampere spherical tokamak (MAST) at low ELM frequencies even though the ELMs exhibit many type III characteristics. These ELMs are associated with a reduction in the pedestal density but no significant change in the pedestal temperature or temperature profile, indicating that energy is convected from the pedestal region into the scrape-off layer. Power to the targets during an ELM arrives predominantly at the low field outboard side. ELM effluxes are observed up to 20 cm from the plasma edge at the outboard mid-plane and are associated with the radial motion of a feature at an average velocity of 0.75 km s−1. The target balance observed in MAST is potentially rather favourable for the ST since H-mode access is facilitated in a regime where ELM losses flow mostly to the large wetted area, outboard targets and, in addition, the target heat loads are reduced by an even distribution of power between the upper and lower targets.

Note: Proc. 19th IAEA Fusion Energy Conference, Lyon, France, October 2002, IAEA-CN-94/EX/OV2-3 Reference CRPP-CONF-2002-068 Record created on 2008-05-13, modified on 2017-05-12

A combination of recently installed state-of-the-art imaging and profile diagnostics, together with established plasma simulation codes, are providing for the first time on Mega Ampere Spherical Tokamak (MAST) the tools required for studying confinement and transport, from the core through to the plasma edge and scrape-off-layer (SOL). The H-mode edge transport barrier is now routinely turned on and off using a combination of poloidally localized fuelling and fine balancing of the X-points. Theory, supported by experiment, indicates that the edge radial electric field and toroidal flow velocity (thought to play an important role in H-mode access) are largest if gas fuelling is concentrated at the inboard side. H-mode plasmas show predominantly type III ELM characteristics, with confinement HH factor (w.r.t. scaling law IPB98[y, 2]) around ~1.0. Combining MAST H-mode data with the International Tokamak Physics Activities (ITPA) analyses, results in an L–H power threshold scaling proportional to plasma surface area (rather than PLH ~ R2). In addition, MAST favours an inverse aspect ratio scaling PLH ~ e0.5. Similarly, the introduction of type III ELMing H-mode data to the pedestal energy regression analysis introduces a scaling Wped ~ e−2.13 and modifies the exponents on R, BT and κ. Preliminary TRANSP simulations indicate that ion and electron thermal diffusivities in ELMing H-mode approach the ion-neoclassical level in the half-radius region of the plasma with momentum diffusivity a few times lower. Linear flux-tube ITG and ETG microstability calculations using GS2 offer explanations for the near-neoclassical ion diffusivity and significantly anomalous electron diffusivity seen on MAST. To complement the baseline quasi-steady-state H-mode, newly developed advanced regimes are being explored. In particular, 'broad' internal transport barriers (ITBs) have been formed using techniques developed at conventional aspect ratio. Electron and ion energy diffusivities are reduced towards the ion-neoclassical level in the ITB region of both co- and counter-injection NBI heated plasmas, with momentum diffusivity up to 10 times lower. Moving out to the edge and SOL, OSM2/EIRENE modelling is being used to extract edge perpendicular particle and heat diffusivities, results being consistent with the ballooning nature of power-flow seen in L-mode and reduction in outboard turbulence seen in ELM-free and inter-ELM H-mode. Modelling of parallel SOL transport requires the inclusion of the mirror force (~10 times higher in MAST than at the conventional aspect ratio) and B2SOLPS5.0 simulations show the edge electric field to be well modelled by neoclassical theory. Transient edge transport phenomena are being studied in detail using a variety of techniques (e.g. probability density function (PDF) and power spectrum analysis, differencing and rescaling methods). Intermittent transport is associated with a radial efflux at up to a tenth of the sound speed and up to 30 cm from the separatrix. Arguably, the most dramatic edge events seen in the plasma periphery are the ELMs. Recent results using fast, high-resolution visible imaging confirm the hypothesis that ELMs have both poloidal and toroidal structures (n ~ 10 at q = 4), consistent with recent theories of the non-linear evolution of ballooning modes.

The scrape-off layer (SOL) and divertor target plasma of a large spherical tokamak (ST) are characterized in detail for the first time. Scalings for the SOL heat flux width in MAST are developed and compared with conventional tokamaks. Modelling reveals the significance of the mirror force to the ST SOL. Core energy losses, including during ELMs, in MAST arrive predominantly (>80%) at the outboard targets in all geometries. Convective transport dominates energy losses during ELMs, and MHD analysis suggests ELMs in MAST are Type III even at auxiliary heating powers well above the L–H threshold. ELMs are associated with a poloidally and/or toroidally localized radial efflux at ~1 km s−1 well into the far SOL but not with any broadening of the target heat flux width. Toroidally asymmetric divertor biasing experiments have been conducted in an attempt to broaden the target heat flux width, with promising results. During vertical displacement events, the maximum product of the toroidal peaking factor and halo current fraction remains below 0.3, around half the ITER design limit. Evidence is presented to demonstrate that the resistance of the halo current path may have an impact on the distribution of the halo current.

The hydraulic design optimization and performance analysis of a mixed-flow pump for marine waterjet propulsion has been carried out using mean streamline analysis and three-dimensional computational fluid dynamics (CFD) code. In the present study, conceptual design optimization has been formulated with a nonlinear objective function to minimize fluid dynamic losses and then a commercial CFD code was incorporated to allow for detailed flow dynamic phenomena in the pump system. The newly designed mixedflow model pump has been tested in the laboratory. Predicted performance curves by the CFD code agree fairly well with experimental data for a newly designed mixed-flow pump over the normal operating conditions. The design and prediction methods presented herein can be used efficiently as a unified hydraulic design process of mixed-flow pumps for marine waterjet propulsion.

Interpretative modelling of the SOL plasma in conventional (JET) and tight (MAST) aspect ratio devices has been performed using OSM2/EIRENE. A detailed comparison has been made of the solutions of the fluid equations and one key issue uncovered by this modelling is the significance of the mirror force for the spherical tokamak (ST) SOL. This force is proportional to ∇∥B/B, which is typically a factor 10 larger in an ST due to the low aspect ratio. This term leads to changes in the charged particle velocity distributions near regions with large V∥B/B representing an effective, upstream particle and momentum source. The modelling performed in this paper indicates that exclusion of the ∇∥B/B term may lead to incorrect conclusions on, for example, the upstream density, especially in STs.

ELM characteristics in a large spherical tokamak with significant auxiliary heating are explored. Access to H-mode is significantly easier when the plasma magnetic configuration is near to a connected double null. The change in ELM frequency with core density and/or auxiliary heating power is broadly similar to conventional devices of a similar size in the type III regime. Power at the targets during an ELM arrives predominantly at the outboard side, irrespective of ELM frequency. The data are consistent with transport into the scrape-off layer being driven predominantly by diffusive processes in quiescent periods between ELMs, and thus being distributed roughly according to the 4:1 ratio of outboard to inboard separatrix surface areas. In L-mode and during ELMs themselves, however, the transport is augmented by turbulent processes, which are more prominent at the outboard side, where the field is very low and where the magnetic surfaces have bad curvature.

The Mega Ampere Spherical Tokamak (MAST) is now accessing regimes with high normalized confinement relative to international scalings, HH(IPB98(y, 2))>~1 at high normalized density, e>60% of the Greenwald density. Data from MAST H-modes suggest that the aspect ratio dependency of international confinement and L–H threshold scalings may need to be modified to improve predictions for ITER. Access to H-mode on MAST is strongly affected by both the divertor magnetic geometry and fuelling location, with the formation of an edge transport barrier being facilitated by operation near the symmetric, connected double-null configuration and with poloidally localized inboard gas puffing. The ELMs on MAST appear to be Type III in nature, even in the highest performance plasmas and with the maximum available auxiliary heating power. ELM energy losses are less than 4% of stored energy in all regimes so far explored. These Type III ELMs are associated with a reduction in the pedestal density but no significant change in the pedestal temperature or temperature profile, indicating that energy is convected from the pedestal region into the scrape-off layer. Analysis of the energy observed to arrive at the divertor targets indicates that ELM losses are predominantly on the low field side. ELM effluxes are observed up to 20 cm from the plasma edge at the outboard mid-plane and are associated with the radial motion of a feature at an average velocity of 1.2 km s−1.

Spontaneous transitions from the low “L-mode” to high “H-mode” of tokamak plasma confinement, first observed during neutral beam heating experiments on ASDEX, are now routinely achieved in many tokamak experiments. The H-mode regime is attractive as it offers the possibility of enhanced confinement, and thus a route towards a more “compact” and cost-efficient fusion power-plant. Transition to H-mode is now routinely achievable in the Mega-Amp Spherical Tokamak (MAST) [A. C. Darke et al., Fusion Technology 1994 (Elsevier, Amsterdam, 1995), Vol. 1, p. 799] for both Ohmically and neutral beam injection (NBI) heated plasmas (PNBI∼0.5–1.7 MW). H-mode plasmas can be either center stack limited or X-point diverted, exhibiting regular Type III edge localized modes (ELMs). Global confinement in H-mode with low frequency ELMs is consistent with the international IPB(y,2) scaling and exceeds the scaling by a factor ∼1.5–2.0 for high performance discharges. Confinement degrades with increasing ELM frequency (which in...

The boundary and divertor plasma of a large spherical tokamak (ST), with significant auxilliary heating, is explored in detail for the first time. The extreme geometry of the ST is found to play a key role, giving rise to strong asymmetries in the transport of heat and particle fluxes (including those during ELMs) towards the outer divertor targets. Preliminary modelling reveals the very significant contribution of magnetic flux expansion to the particle flux balance of the ST scrape-off layer. Divertor detachment at the inboard targets is observed in L-mode at moderate core densities for plasmas with up to 1 MW of auxilliary heating.

Fast-wave heating will be a major heating scheme on ITER, as it can heat ions directly and is relatively unaffected by the large machine size unlike neutral beams. However, fast-wave interactions with the plasma edge can lead to deleterious effects such as, in the case of the high-harmonic fast-wave (HHFW) system on NSTX, large losses of fast-wave power in the scrape off layer (SOL) under certain conditions. In such scenarios, a large fraction of the lost HHFW power is deposited on the upper and lower divertors in bright spiral shapes. The responsible mechanism(s) has not yet been identified but may include fast-wave propagation in the scrape off layer, parametric decay instability, and RF currents driven by the antenna reactive fields. Understanding and mitigating these losses is important not only for improving the heating and current-drive on NSTX-Upgrade but also for understanding fast-wave propagation across the SOL in any fast-wave system. This talk summarizes experimental results demonstrating that the flow of lost HHFW power to the divertor regions largely follows the open SOL magnetic field lines. This lost power flux is relatively large close to both the antenna and the last closed flux surface with a reduced level in between, so the loss mechanism cannot be localized to the antenna. At the same time, significant losses also occur along field lines connected to the inboard edge of the bottom antenna plate. The power lost within the spirals is roughly estimated, showing that these field-aligned losses to the divertor are significant but may not account for the total HHFW loss. To elucidate the role of the onset layer for perpendicular fast-wave propagation with regards to fast-wave propagation in the SOL, a cylindrical cold-plasma model is being developed. This model, in addition to advanced RF codes such as TORIC and AORSA, is aimed at identifying the underlying mechanism(s) behind these SOL losses, to minimize their effects in NSTX-U, and to predict their importance in ITER.

Field-aligned losses of HHFW power in the SOL of NSTX have been studied with IR cameras and probes, but the interpretation of the data depends somewhat on the magnetic equilibrium reconstruction. Both EFIT02 and LRDFIT04 magnetic equilibria have been used with the SPIRAL code to provide field mappings in the scrape off layer (SOL) on NSTX from the midplane SOL in front of the HHFW antenna to the divertor regions, where the heat deposition spirals are measured. The field-line mapping spiral produced at the divertor plate with LRDFIT04 matches the HHFW-produced heat deposition best, in general. An independent method for comparing the field-line strike patterns on the outer divertor for the two equilibria is provided by measuring Langmuir probe characteristics in the vicinity of the outer vessel strike radius (OVSR) and observing the effect on floating potential, saturation current, and zero-probe-voltage current (IV=0) with the crossing of the OVSR over the probe. Interestingly, these comparisons also reveal that LRDFIT04 gives the more accurate location of the predicted OVSR, and confirm that the RF power flow in the SOL is essentially along the magnetic field lines. Also, the probe characteristics and IV=0 data indicate that current flows under the OVSR in the divertor tiles in most cases studied.

Initial target plasma parameters have been obtained using Langmuir probe arrays in MAST DND plasmas. A clear in–out asymmetry was observed in the target parameters. All plasma parameter scale lengths were significantly elongated on the outboard side due to strong poloidal flux expansion. The electron temperature scale length λTe is typically 5–8 times broader than the density scale length λne, suggesting a significant difference between heat and particle diffusivities in the SOL. A rough estimation of the SOL collisionality indicates that the inner SOL may be collisional (ν*∼50) whereas the outer SOL is marginally collisional (ν*∼7). The peak power density is about 4–5 times higher (∼1 MW m −2 ) on the inboard side, which has a SOL power density scale length ∼10 times narrower (∼0.5 cm) than the outboard. The total power flow was approximately up–down symmetric, whilst the in–out power asymmetry was observed to be Pin:Pout∼1:6.5, exceeding the ratio of ∼1:3 for the inboard and outboard separatrix surface areas. A total of about 2/3 of the power entering the SOL reached the strike points (300 kW out of P SOL ∼450 kW ).

Spark gaps are widely used switches for the development of high power pulser systems because of their simplicity and fast switching capability. We have already developed a pulser system using a single microplasma-assisted spark gap to generate short electrical pulses at the load with a repetition rate of 1 MHz. The single spark gap pulser system undergoes a few drawbacks such as low breakdown voltage and charging efficiency etc. The breakthrough of this problem is achieved by a parallel operation of two similar spark gaps in the pulser system by reducing the repetition rate, thereby increasing the voltage recovery of each spark gap. The operation of the pulser system with optimized charging circuit and spark gap parameters exhibited improved breakdown voltage and charging efficiency. Finally, the pulser system is extended for the parallel operation of four spark gaps system.

A damped sinusoidal (DS) oscillator system has been designed and fabricated in our laboratory. The system consists of a primary power source, a Marx generator, a transmission line oscillator, and a helical antenna. A Marx generator is used to feed 300kV high voltage pulse to the DS oscillator. The designed characteristic impedance and average switching voltage of the DS oscillator is 6.3 ohm and 300kV respectively. The axial mode helical antenna is designed to operate at a frequency around 250MHz. The whole DS oscillator system has been simulated using FEMM, Pspice and CST MWS. The measured maximum horizontal electric field is 18kV/m at a range of 10m when the transmission line oscillator is charged with 230kV. This paper describes works performed in initial design stage, computer simulation stage, and test results of our manufactured DS system.

Annual Target: Conduct experiments on major fusion facilities to improve understanding of the heat transport in the tokamak scrape-off layer (SOL) plasma, strengthening the basis for projecting divertor conditions in ITER. The divertor heat flux profiles and plasma characteristics in the tokamak scrape-off layer will be measured in multiple devices to investigate the underlying thermal transport processes. The unique characteristics of C-Mod, DIII-D, and NSTX will enable collection of data over a broad range of SOL and divertor parameters (e.g., collisionality ν*, beta β, parallel heat flux q||, and divertor geometry). Coordinated experiments using common analysis methods will generate a data set that will be compared with theory and simulation.

ELMs reduce the stored energy achieved with HHFW heating compared with the ELM free case as also occurs for NBI heating alone. This reduction can be attributed both to direct ELM ejection of stored energy and to an increase in edge density with ELMs that exceeds the onset density for perpendicular wave propagation near the antenna [1,2], and leads to significantly more edge RF power deposition. This latter effect causes a more intense RF “hot” zone in the lower divertor scrape off region due to an increase in edge RF power propagating to the divertor from the antenna region along the magnetic field lines. Fast IR measurements of the direct ELM heat deposition at the lower divertor shows it to be peaked in the vicinity of the outer strike radius and to fall off strongly as the “hot” zone is approached, indicating little direct ELM effect on the “hot” zone heating. Physics studies of the “hot” zone have begun with sweeping the RF “hot” zone spiral over Rogowski instrumented divertor region tiles to show tha...

Total knee arthroplasty is a reliable procedure for the treatment of severely damaged knee joints in patients with osteoarthritis or rheumatoid arthritis. Despite good long-term results, the ultimate failure mode of TKA is osteolysis caused by wear debris from polyethylene. The osteolysis tends to cause aseptic loosening and instability of components, which leads to pain and revision [8,17]. Certainly, in case of elderly patients with lower activity levels, even total knee prostheses with conventional design and materials have achieved excellent long-term results. Over the past 10 years, however, greater demands are recently placed on total knee arthroplasties for younger, more active patients [24]. Therefore, in an attempt to minimize such PE wear, several modifications of the traditional approach to TKR have been introduced. Implant design and surgical instruments are continuously developing, including the use of more conforming articular surfaces [7]. Improvements in manufacturing quality, elimination of sterilization by gamma irradiation in air and cross-linking have reduced the PE wear [16,64]. However, wear and mechanical failures of gamma inert sterilized and highly cross-linked polyethylene have been observed [11,12].

In the general area of confinement improvement and concept advancement, recent results in the Madison Symmetric Torus (MST) reversed-field pinch (RFP) include good confinement of both thermal and large-orbit ions and near doubling of total beta to 26% with deuterium pellet injection. Current profile control enables MST to reduce stochastic transport and achieve tokamak-like confinement. In standard RFP operation, substantial MHD tearing mode activity results in stochastic transport and an energy confinement time of about 1 ms in MST. Application of inductive current profile control reduces MHD activity and accompanying stochasticity, improving confinement by about a factor of ten. Previous work concentrated on electron confinement in improved-confinement RFP operation. Recent work confirms that ions are also well confined, and that high beta and improved confinement can be achieved simultaneously. PACS numbers: 52.55.Hc, 52.55.Dy (Some figures in this article are in colour only in the electronic version)

The MAST (Mega-Amp Spherical Tokamak) experiment has been operational since Jan 2000. Results from MAST are important both in evaluating the potential of future ST fusion devices, and in developing understanding of processes relevant to conventional aspect ratio tokamaks. In this paper methods of initiating, ramping up, and sustaining the high plasma currents associated with ST fusion devices are discussed. New physics results, including the effectiveness of inboard gas puffing, the threshold power required for the L-H transition, and the 'natural' divertor configuration are given. Plans for improvements during 2002 are outlined.

Enhanced diagnostics and an expanded operational space in Mega Ampere Spherical Tokamak (MAST) has lead to a wealth of data on the plasma boundary becoming available over the last year of operations and has significantly advanced the understanding of this region in the spherical tokamak and, more generally, is contributing to an improved understanding of the underlying plasma phenomena for this important region of the tokamak. Amongst the observations reported in this paper are that MAST is able to achieve simultaneous high confinement and high density with Type III ELMs for connected double-null discharges in which most (>93%) of the power efflux from the core observed at the targets (including during ELMs) arrives at the large wetted area outboard targets and is evenly distributed between the upper and lower divertor regions. Significant particle fluxes are reported well beyond the outboard separatrix during ELMs (up to 20 cm distant from the plasma) and appear to be associated with the radial expansion of a localised structure at around 1 km s −1 . The result of preliminary experiments to broaden the SOL by asymmetric divertor biasing are also presented which show an encouraging, qualitative agreement with theory and demonstrate clear evidence for both SOL broadening and target power reduction.

Transport and turbulence profiles were directly evaluated using probes for the first time in the edge and scrape-off layer (SOL) of NSTX [Ono et al., Nucl. Fusion 40, 557 (2000)] in low (L) and high (H) confinement, low power (Pin∼ 1.3 MW), beam-heated, lower single-null discharges. Radial turbulent particle fluxes peak near the last closed flux surface (LCFS) at ≈4×1021 s−1 in L-mode and are suppressed to ≈0.2×1021 s−1 in H mode (80%–90% lower) mostly due to a reduction in density fluctuation amplitude and of the phase between density and radial velocity fluctuations. The radial particle fluxes are consistent with particle inventory based on SOLPS fluid modeling. A strong intermittent component is identified. Hot, dense plasma filaments 4–10 cm in diameter, appear first ∼2 cm inside the LCFS at a rate of ∼1×1021 s−1 and leave that region with radial speeds of ∼3–5 km/s, decaying as they travel through the SOL, while voids travel inward toward the core. Profiles of normalized fluctuations feature levels o...

First physics results are presented from MAST (Mega-Amp Spherical Tokamak), one of the new generation of purpose built spherical tokamaks (STs) now commencing operation. Some of these results demonstrate, for the first time, the novel effects of low aspect ratio, for example, the enhancement of resistivity due to neo-classical effects. H-mode is achieved and the transition to H-mode is accompanied by a tenfold steepening of the edge density gradient which may enable the successful application of electron Bernstein wave heating in STs. Studies of halo currents show that these less than expected from conventional tokamak results, and measurements of divertor power loading confirm that most of the power flows to the outer strike points, easing the power handling on the inner points (a critical issue for STs). (C) 2001 American Institute of Physics.

This study was performed to investigate the effect of of transdermal testosterone gel (TTG) on controlled ovarian stimulation (COS) and IVF outcomes and ovarian morphology according to pretreatment duration in poor responders. A total of 120 women were recruited for this pilot study. They were randomized into control, 2 weeks, 3 weeks or 4 weeks TTG treatment groups. For three TTG treatment groups, 12.5 mg TTG was applied daily for 2 weeks, 3 weeks or 4 weeks in preceding period of study stimulation cycle. After 3 weeks of TTG pretreatment, significant increase of antral follicle count (AFC) and significant decreases of mean follicular diameter (MFD) and resistance index (RI) value of ovarian stromal artery were observed (p=0.026, p

The growth-inhibitory activity of Galla Rhois-derived materials towards 17 intestinal bacteria was evaluated using an impregnated paper disc method. The biologically active components of Galla Rhois were characterized as the tannins methyl gallate (MG) and gallic acid (GA) by spectral analysis. The growth responses varied with bacterial strain tested. In the test using 10 mg disc-1, MG and GA produced a clear inhibitory effect on harmful bacteria such as Clostridium perfringens, Cl. paraputrificum, Eubacterium limosum, Bacteroides fragilis, Staphylococcus aureus and Escherichia coli. Methyl gallate showed no growth-inhibitory activity towards Bifidobacterium adolescentis or B. longum whereas the growth of B. bifidum, B. breve, B. infantis, B. animalis, B. thermophilum, Lactobacillus acidophilus, Lact. plantarum and Streptococcus faecalis was slightly affected. However, GA did not adversely affect the growth of the bifidobacteria and lactobacilli. At 5 mg disc-1, MG significantly inhibited the growth of Cl. perfringens and Cl. paraputrificum but did not affect the growth of the bifidobacteria and lactobacilli. At 1 mg disc-1, MG greatly inhibited the growth of Cl. perfringens alone. These results may be an indication of at least one of the pharmacological actions of Galla Rhois.

OBJECTIVE: To investigate the effect of intravenous immunoglobulin (IVIG) treatment on pregnancy outcome following IVF/ICSI in infertile patients with endometriosis. DESIGN: Prospective, randomized controlled trial. MATERIALS AND METHODS: A total of 120 infertile patients with stage III or IV endometriosis were randomized in a 2:1 ratio to IVIG treatment group or control group. GnRH agonist (GnRH-a) long protocol was used for controlled ovarian stimulation (COS) in all subjects. For the treatment group (n1⁄480), 10 gm of IVIG were administered on the day of oocyte retrieval. One to three embryos were transferred into the uterus on the third day after oocyte retrieval. The primary endpoint was the embryo implantation rate. RESULTS: Patient’s characteristics were comparable in the treatment and control groups. There were also no significant differences with respect to COS and IVF results between the two groups. However, embryo implantation rate was significantly higher in the treatment group of 22.3% (50/ 224) compared with 12.2% (14/115) in control group (P1⁄40.024). Clinical pregnancy rate (CPR) was higher in the treatment group with a borderline significance (P1⁄40.052). In singleton pregnant women following IVF/ICSI, serum b-hCG level on the eleventh day after embryo transfer was significantly higher in the treatment group of 180.2 45.7 mIU/ml compared with 82.8 26.7 mIU/ml in the control group (P

Small, nonaxisymmetric magnetic perturbations generated by external coils have been found to break the axisymmetry of heat and particle flux deposition pattern in the divertor area in the National Spherical Torus Experiment (NSTX). This breaking by the applied 3-D field causes strike point splitting that is represented as local peaks and valleys in the divertor profiles. In case of n = 3 fields application, the broken toroidal symmetry of the divertor profile shows 120° of spatial periodicity while data for n = 1 fields provide a fully nonaxisymmetric heat and particle deposition. Field line tracing showed good agreement with the measured heat and particle flux profiles. Higher toroidal mode number (n = 3) of the applied perturbation produced more and finer striations in the divertor profiles than in the lower mode number (n = 1) case. Following the previous result of the intrinsic strike point splitting by the n = 3 error fields [Nucl. Fusion 50, 045010 (2010); J. Nucl. Mater. (2011), doi:10.1016/j.jnucm...

Reduced model simulations of turbulence in the edge and scrape-off-layer (SOL) region of a spherical torus or tokamak plasma are employed to address the physics of the scrape-off-layer heat-flux width. The simulation model is an electrostatic two-dimensional fluid turbulence model, applied in the plane perpendicular to the magnetic field at the outboard midplane of the torus. The model contains curvature-driven-interchange modes, sheath losses, and both perpendicular turbulent diffusive and convective (blob) transport. These transport processes compete with classical parallel transport to set the SOL width. Midplane SOL profiles of density, temperature, and parallel heat flux are obtained from the simulation and compared with experimental results from the National Spherical Torus Experiment [S. M. Kaye et al., Phys. Plasmas 8, 1977 (2001)] to study the scaling of the heat-flux width with power and plasma current. It is concluded that midplane turbulence is the main contributor to the SOL heat-flux width f...

Steady-state handling of divertor heat flux is a critical issue for ITER and future conventional and spherical tokamaks with compact high-power density divertors. A novel ‘snowflake’ divertor (SFD) configuration was theoretically predicted to have significant magnetic geometry benefits for divertor heat flux mitigation, such as an increased plasma-wetted area and a higher divertor volume available for volumetric power and momentum loss processes, as compared with the standard divertor. Both a significant divertor peak heat flux reduction and impurity screening have been achieved simultaneously with core H-mode confinement in discharges with the SFD using only a minimal set of poloidal field coils.

We have increased substantially the electron and ion temperatures, the electron density, and the total beta in plasmas with improved energy confinement in the Madison Symmetric Torus (MST). The improved confinement is achieved with a well-established current profile control technique for reduction of magnetic tearing and reconnection. A sustained ion temperature >1 keV is achieved with intensified reconnection-based ion heating followed immediately by current profile control. In the same plasmas, the electron temperature reaches 2 keV, and the electron thermal diffusivity drops to about 2 m2 s−1. The global energy confinement time is 12 ms. This and the reported temperatures are the largest values yet achieved in the reversed-field pinch (RFP). These results were attained at a density ∼1019 m−3. By combining pellet injection with current profile control, the density has been quadrupled, and total beta has nearly doubled to a record value of about 26%. The Mercier criterion is exceeded in the plasma core, and both pressure-driven interchange and pressure-driven tearing modes are calculated to be linearly unstable, yet energy confinement is still improved. Transient momentum injection with biased probes reveals that global momentum transport is reduced with current profile control. Magnetic reconnection events drive rapid momentum transport related to large Maxwell and Reynolds stresses. Ion heating during reconnection events occurs globally, locally, or not at all, depending on which tearing modes are involved in the reconnection. To potentially augment inductive current profile control, we are conducting initial tests of current drive with lower-hybrid and electron-Bernstein waves.

Pellet fuelling of improved confinement Madison Symmetric Torus (MST) plasmas has resulted in high density and high plasma beta. The density in improved confinement discharges has been increased fourfold, and a record plasma beta (βtot = 26%) for the improved confinement reversed-field pinch (RFP) has been achieved. At higher β, a new regime for instabilities is accessed in which local interchange and global tearing instabilities are calculated to be linearly unstable, but experimentally, no severe effect, e.g., a disruption, is observed. The tearing instability, normally driven by the current gradient, is driven by the pressure gradient in this case, and there are indications of increased energy transport (as compared with low-density improved confinement). Pellet fuelling is also compared with enhanced edge fuelling of standard confinement RFP discharges for the purpose of searching for a density limit in MST. In standard-confinement discharges, pellet fuelling peaks the density profile where edge fuelling cannot, but transport appears unchanged. For a limited range of plasma current, MST discharges with edge fuelling are constrained to a maximum density corresponding to the Greenwald limit. This limit is surpassed in pellet-fuelled improved confinement discharges.