The hidden cochlear implant.

OBJECTIVE: The hidden cochlear implant concept has two data transmission methods: Bluetooth low energy and transtympanic optical data transfer systems. This study aimed to present the hidden cochlear implant and compare the test results with the existing fully implanted cochlear implant. METHOD: The Bluetooth low energy module was implanted into the implant bed. For the transtympanic optical data transfer tests, a receiver was passed through the posterior tympanotomy, and the transmitter was placed in the ear canal. RESULTS: The Bluetooth low energy module range was 5.2-17.5 m. Transtympanic optical data transfer reached a rate of 1 Mbit/s and had 99.22 per cent accuracy. Despite various obstacles, the accuracy of the transtympanic optical data transfer was more than 99 per cent with a 250 Kbit/s rate. The average power consumption was 310 mW for the implanted Bluetooth low energy module and 41 mW for the transtympanic optical data transfer receiver. CONCLUSION: Bluetooth low energy is suitable to be used transcutaneously. Transtympanic optical data transfer is an effective and promising technology. Hidden use cochlear implants aim to have the aesthetics of a fully implantable cochlear implant with higher reliability and a magnet-free design with smart device integration.

6-Phosphofructo-2-kinase/fructose-2,6-biphosphatase 4 is essential for p53-null cancer cells.

The bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase-4 (PFKFB4) controls metabolic flux through allosteric regulation of glycolysis. Here we show that p53 regulates the expression of PFKFB4 and that p53-deficient cancer cells are highly dependent on the function of this enzyme. We found that p53 downregulates PFKFB4 expression by binding to its promoter and mediating transcriptional repression via histone deacetylases. Depletion of PFKFB4 from p53-deficient cancer cells increased levels of the allosteric regulator fructose-2,6-bisphosphate, leading to increased glycolytic activity but decreased routing of metabolites through the oxidative arm of the pentose-phosphate pathway. PFKFB4 was also required to support the synthesis and regeneration of nicotinamide adenine dinucleotide phosphate (NADPH) in p53-deficient cancer cells. Moreover, depletion of PFKFB4-attenuated cellular biosynthetic activity and resulted in the accumulation of reactive oxygen species and cell death in the absence of p53. Finally, silencing of PFKFB4-induced apoptosis in p53-deficient cancer cells in vivo and interfered with tumour growth. These results demonstrate that PFKFB4 is essential to support anabolic metabolism in p53-deficient cancer cells and suggest that inhibition of PFKFB4 could be an effective strategy for cancer treatment.

Ultra-fast charge exchange spectroscopy for turbulent ion temperature fluctuation measurements on the DIII-D tokamak (invited).

A novel two-channel, high throughput, high efficiency spectrometer system has been developed to measure impurity ion temperature and toroidal velocity fluctuations associated with long-wavelength turbulence and other plasma instabilities. The spectrometer observes the emission of the n = 8-7 hydrogenic transition of C(+5) ions (λ(air) = 529.06 nm) resulting from charge exchange reactions between deuterium heating beams and intrinsic carbon. Novel features include a large, prism-coupled high-dispersion, volume-phase-holographic transmission grating and high-quantum efficiency, high-gain, low-noise avalanche photodiode detectors that sample emission at 1 MHz. This new diagnostic offers an order-of-magnitude increase in sensitivity compared to earlier ion thermal turbulence measurements. Increased sensitivity is crucial for obtaining enough photon statistics from plasmas with much less impurity content. The irreducible noise floor set by photon statistics sets the ultimate sensitivity to plasma fluctuations. Based on the measured photon flux levels for the entire spectral line, photon noise levels for T̃(i)/T(i) and V(i)/V(i) of ~1% are expected, while statistical averaging over long data records enables reduction in the detectable plasma fluctuation levels to values less than that. Broadband ion temperature fluctuations are observed to near 200 kHz in an L-mode discharge. Cross-correlation with the local beam emission spectroscopy measurements demonstrates a strong coupling of the density and temperature fields, and enables the cross-phase measurements between density and ion temperature fluctuations.

Ultrafast spectroscopy diagnostic to measure localized ion temperature and toroidal velocity fluctuations.

A dual-channel high-efficiency, high-throughput custom spectroscopic system has been designed and implemented at DIII-D to measure localized ion thermal fluctuations associated with drift wave turbulence. A large-area prism-coupled transmission grating and high-throughput collection optics are employed to observe C VI emission centered near λ=529 nm. The diagnostic achieves 0.25 nm resolution over a 2.0 nm spectral band via eight discrete spectral channels. A turbulence-relevant time resolution of 1 µs is achieved using cooled high-speed avalanche photodiodes and ultralow-noise preamplifiers. The system sensitivity is designed to provide measurements of normalized ion temperature fluctuations on the order of δT(i)/T(i)≤1%.

Overview of the beam emission spectroscopy diagnostic system on the National Spherical Torus Experiment.

A beam emission spectroscopy (BES) system has been installed on the National Spherical Torus Experiment (NSTX) to study ion gyroscale fluctuations. The BES system measures D(α) emission from a deuterium neutral heating beam. The system includes two optical views centered at r/a≈0.45 and 0.85 and aligned to magnetic field pitch angles at the neutral beam. f/1.5 collection optics produce 2-3 cm spot sizes at the neutral beam. The initial channel layout includes radial arrays, poloidal arrays, and two-dimensional grids. Radial arrays provide coverage from r/a≈0.1 to beyond the last-closed flux surface. Photodetectors and digital filters provide high-sensitivity, low-noise measurements at frequencies of up to 1 MHz. The BES system will be a valuable tool for investigating ion gyroscale turbulence and Alfvén/energetic particle modes on NSTX.

Low-noise, high-speed detector development for optical turbulence fluctuation measurements for NSTX.

A new beam emission spectroscopy (BES) diagnostic is under development. Photon-noise limited measurements of neutral beam emissions are achieved using photoconductive photodiodes with a novel frequency-compensated broadband preamplifier. The new BES system includes a next-generation preamplifier and upgraded optical coupling system. Notable features of the design are surface-mount components, minimized stray capacitance, a wide angular acceptance photodiode, a differential output line driver, reduced input capacitance, doubling of the frequency range, net reduced electronic noise, and elimination of the need for a cryogenic cooling system. The irreducible photon noise dominates the noise up to 800 kHz for a typical input power of 60 nW. This new assembly is being integrated into an upgraded multichannel optical detector assembly for a new BES system on the NSTX experiment.

Wide-field turbulence imaging with beam emission spectroscopy.

Imaging of the size, shape, time-averaged, and time-resolved dynamics of long-wavelength density turbulence structures is accomplished with an expanded, high-sensitivity, wide-field beam emission spectroscopy (BES) diagnostic on DIII-D. A 64-channel BES system is configured with an 8×8 grid of discrete channels that image an approximately 7×9 cm region at the outboard midplane. The grid covers multiple correlation lengths and each channel shape matches the measured radial-poloidal correlation length asymmetry of turbulent eddies. The wide field 8×8 imaging capability allows for sampling of essentially the full two-dimensional spatial correlation function for typical plasma conditions. The sampled area can be radially scanned over 0.4