324 research outputs found
Detection of mechanical resonance of a single-electron transistor by direct current
We have suspended an Al based single-electron transistor whose island can
resonate freely between the source and drain leads forming the clamps. In
addition to the regular side gate, a bottom gate with a larger capacitance to
the SET island is placed underneath to increase the SET coupling to mechanical
motion. The device can be considered as a doubly clamped Al beam that can
transduce mechanical vibrations into variations of the SET current. Our
simulations based on the orthodox model, with the SET parameters estimated from
the experiment, reproduce the observed transport characteristics in detail.Comment: 4 pages, 3 figure
A study of turbofan-engine compressor noise suppression techniques
Nacelle design for turbofan engine compressor noise suppression on Douglas DC-8 aircraf
Impacts of good practice policies on regional and global greenhouse gas emissions
The report looks at the impact of "good practice"emission reduction policies in nine different areas globally and across six countries: China, Brazil, India, the US, Russia and Japan.
These include renewable energy, a variety of energy efficiency standards (buildings, car fuel efficiecy, appliances and lighting, industry), hydrofluorocarbons (HFC.s), emissions from fossil fuel production, electric cars and forestry.
The authors looked at the most ambitious "good practice" policies around the world that are being implemented now, and calculated the difference these would make if everybody were to apply them.
If all governments follow those governments that currently adopt the best climate policies in just nin different areas, they could reduce emissions close to the levels needed to stay on track to hold global warming below 2 degrees C.
The implementation of good practice policies is projected to stabilise greenhouse gas emissions at 49-50 GtCO2e by 2020, and decrease to 44- 47 GtCO2e by 2030- close to the 2 degrees C emissions range (30-44 GtCO2e) by 2030.
Direct replication of good practice policies is projected to halt emissions growth in most regions sinificantly before 2030. In contrast, current policies are expected to see emissions to increase to around 54 GtCO2e by 2020 and 59-60 GtCO2e by 2030
The Search for the QGP: A Critical Appraisal
Over the past 15 years, an extensive program of high energy nuclear
collisions at BNL and CERN has been devoted to the experimental search for the
quark-gluon plasma predicted by QCD. The start of RHIC this year will increase
the highest available collision energy by a factor 10. This seems a good time
for a critical assessment: what have we learned so far and what can we hope to
learn in the coming years?Comment: 20 pages, 20 figure
Assessment of tumor redox status through (S)-4-(3-[18F]fluoropropyl)-L-glutamic acid positron emission tomography imaging of system xc- activity
The cell's endogenous antioxidant system is vital to maintenance of redox homeostasis. Despite its central role in normal and pathophysiology, no non-invasive tools exist to measure this system in patients. The cystine/glutamate antiporter system xc- maintains the balance between intracellular reactive oxygen species and antioxidant production through the provision of cystine, a key precursor in glutathione biosynthesis. Here we show that tumor cell retention of a system xc--specific positron emission tomography radiotracer, (S)-4-(3-[18F]fluoropropyl)-L-glutamic acid ([18F]FSPG), decreases in proportion to levels of oxidative stress following treatment with a range of redox-active compounds. The decrease in [18F]FSPG retention correlated with a depletion of intracellular cystine resulting from increased de novo glutathione biosynthesis, shown through [U-13C6, U-15N2]cystine isotopic tracing. In vivo, treatment with the chemotherapeutic doxorubicin decreased [18F]FSPG tumor uptake in a mouse model of ovarian cancer, coinciding with markers of oxidative stress but preceding tumor shrinkage and decreased glucose utilization. Having already been used in pilot clinical trials, [18F]FSPG PET could be rapidly translated to the clinic as an early redox indicator of tumor response to treatment
NPHP4, a cilia-associated protein, negatively regulates the Hippo pathway
The cilia-associated protein NPHP4 is a negative regulator of Hippo signaling that modulates cell proliferation in mammals
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