94 research outputs found
Field Effect Transistors for Terahertz Detection: Physics and First Imaging Applications
Resonant frequencies of the two-dimensional plasma in FETs increase with the
reduction of the channel dimensions and can reach the THz range for sub-micron
gate lengths. Nonlinear properties of the electron plasma in the transistor
channel can be used for the detection and mixing of THz frequencies. At
cryogenic temperatures resonant and gate voltage tunable detection related to
plasma waves resonances, is observed. At room temperature, when plasma
oscillations are overdamped, the FET can operate as an efficient broadband THz
detector. We present the main theoretical and experimental results on THz
detection by FETs in the context of their possible application for THz imaging.Comment: 22 pages, 12 figures, review pape
miR-17-5p regulates endocytic trafficking through targeting TBC1D2/ Armus
miRNA cluster miR-17-92 is known as oncomir-1 due to its potent oncogenic function. miR-17-92 is a polycistronic cluster that encodes 6 miRNAs, and can both facilitate and inhibit cell proliferation. Known targets of miRNAs encoded by this cluster are largely regulators of cell cycle progression and apoptosis. Here, we show that miRNAs encoded by this cluster and sharing the seed sequence of miR-17 exert their influence on one of the most essential cellular processes – endocytic trafficking. By mRNA expression analysis we identified that regulation of endocytic trafficking by miR-17 can potentially be achieved by targeting of a number of trafficking regulators. We have thoroughly validated TBC1D2/Armus, a GAP of Rab7 GTPase, as a novel target of miR-17. Our study reveals regulation of endocytic trafficking as a novel function of miR-17, which might act cooperatively with other functions of miR-17 and related miRNAs in health and disease
Low frequency 1/f noise in doped manganite grain-boundary junctions
We have performed a systematic analysis of the low frequency 1/f-noise in
single grain boundary junctions in the colossal magnetoresistance material
La_{2/3}Ca_{1/3}MnO_{3-delta}. The grain boundary junctions were formed in
epitaxial La_{2/3}Ca_{1/3}MnO_{3-delta} films deposited on SrTiO_3 bicrystal
substrates and show a large tunneling magnetoresistance of up to 300% at 4.2 K
as well as ideal, rectangular shaped resistance versus applied magnetic field
curves. Below the Curie temperature T_C the measured 1/f noise is dominated by
the grain boundary. The dependence of the noise on bias current, temperature
and applied magnetic field gives clear evidence that the large amount of low
frequency noise is caused by localized sites with fluctuating magnetic moments
in a heavily disordered grain boundary region. At 4.2 K additional temporally
unstable Lorentzian components show up in the noise spectra that are most
likely caused by fluctuating clusters of interacting magnetic moments. Noise
due to fluctuating domains in the junction electrodes is found to play no
significant role.Comment: 9 pages, 7 figure
Real-Time Analysis Of THz Quantum-Cascade Laser Signals Using A Field Effect Transistor Array
Diastolic time – frequency relation in the stress echo lab: filling timing and flow at different heart rates
A cutaneous force-frequency relation recording system based on first heart sound amplitude vibrations has been recently validated. Second heart sound can be simultaneously recorded in order to quantify both systole and diastole duration
YIP1 family member 4 (YIPF4) is a novel cellular binding partner of the papillomavirus E5 proteins
E5 proteins are amongst the least understood of the Human Papillomavirus (HPV) encoded gene products. They are small, membrane-integrated proteins known to modulate a number of critical host pathways associated with pathogenesis including growth factor receptor signaling and immune evasion. Their role in the virus life cycle is less clear, indicating a role in the productive stages of the life cycle. However, a mechanism for this is currently lacking. Here we describe the identification of a novel binding partner of E5, YIPF4 using yeast two-hybrid analysis. YIPF4 is also a poorly characterized membrane spanning protein. Mutagenesis studies implicated the transmembrane regions of each protein as important for their interaction. Binding to YIPF4 was found for all E5 proteins tested suggesting that this interaction may mediate a conserved E5 function. In normal human keratinocytes YIPF4 expression was down-regulated upon differentiation and this reduction was partially rescued in cells harbouring HPV. Despite the conserved nature of the interaction with E5, siRNA mediated depletion of YIPF4 failed to impede two well-characterized functions of E5, namely EGFR trafficking or HLA class I presentation. Continued studies of YIPF4 are warranted to determine its role in the PV life cycle
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