In HL-2A and J-TEXT ohmic confinement regimes, an electrostatic turbulence with quasi-coherent characteristics in spectra of density fluctuations was observed by multi-channel microwave reflectometers. These quasi-coherent modes (QCMs) were detectable in a large plasma region (r/a∼0.3−0.8). The characteristic frequencies of QCMs were in the range of 30–140 kHz. The mode is rotated in the electron diamagnetic direction. In the plasmas with QCMs, trapped electron mode (TEM) was predicted to be unstable by gyrokinetic simulations. The combined experimental results show that the TEM is survived in the linear ohmic confinement regime of plasmas. The quasi-coherent TEM was replaced by broad-band fluctuations when the plasma transits from linear to saturated ohmic confinement regime. The observation was strongly related to the turbulence transition from TEM to ion temperature gradient mode. A critical gradient threshold for TEM excitation in electron temperature gradient was directly found. The effect of TEM on density profile peaking was presented.
To meet experimental requirements, the J-TEXT electron cyclotron emission (ECE) diagnostic is being upgraded. The front end antenna and transmission line have been modified and a new 8-channel W-band detecting unit has been developed. The improved ECE system will extend the frequency range from 94.5-124.5 GHz to 80.5-124.5 GHz. This will enable the system to cover the most plasma in the radius direction for B = 1.8-2.2 T, and it even can cover almost the whole plasma range ρ = - 0.8-0.9 (minus means the high field side) at B = 1.8 T. A new auxiliary channel bank with 8 narrow band, tunable yttrium iron garnet filters is planned to add to the ECE system. Due to observations along a major radius, perpendicular to B, and relatively low electron temperature, Doppler and relativistic broadening are minimal and thus high spatial resolution measurements can be made at variable locations with these tunable channels.
Although there are currently 62 mutants of Cx43 (connexin43) that can cause ODDD (oculodentodigital dysplasia), only two mutants have also been reported to cause palmar plantar hyperkeratosis. To determine how mutants of Cx43 can lead to this skin disease, REKs (rat epidermal keratinocytes) were engineered to express an ODDD-associated Cx43 mutant always linked to skin disease (fs260), an ODDD-linked Cx43 mutant which has been reported to sometimes cause skin disease (fs230), Cx43 mutants which cause ODDD only (G21R, G138R), a mouse Cx43 mutant linked to ODDD (G60S), a non-disease-linked truncated Cx43 mutant that is trapped in the endoplasmic reticulum (Δ244*) or full-length Cx43. When grown in organotypic cultures, of all the mutants investigated, only the fs260-expressing REKs consistently developed a thinner stratum corneum and expressed lower levels of Cx43, Cx26 and loricrin in comparison with REKs overexpressing wild-type Cx43. REKs expressing the fs260 mutant also developed a larger organotypic vital layer after acetone-induced injury and exhibited characteristics of parakeratosis. Collectively, our results suggest that the increased skin disease burden exhibited in ODDD patients harbouring the fs260 mutant is probably due to multiple additive effects cause by the mutant during epidermal differentiation.
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