224 research outputs found
Multiplexed readout of kinetic inductance bolometer arrays
Kinetic inductance bolometer (KIB) technology is a candidate for passive
sub-millimeter wave and terahertz imaging systems. Its benefits include
scalability into large 2D arrays and operation with intermediate cryogenics in
the temperature range of 5 -- 10 K. We have previously demonstrated the
scalability in terms of device fabrication, optics integration, and cryogenics.
In this article, we address the last missing ingredient, the readout. The
concept, serial addressed frequency excitation (SAFE), is an alternative to
full frequency-division multiplexing at microwave frequencies conventionally
used to read out kinetic inductance detectors. We introduce the concept, and
analyze the criteria of the multiplexed readout avoiding the degradation of the
signal-to-noise ratio in the presence of a thermal anti-alias filter inherent
to thermal detectors. We present a practical scalable realization of a readout
system integrated into a prototype imager with 8712 detectors. This is used for
demonstrating the noise properties of the readout. Furthermore, we present
practical detection experiments with a stand-off laboratory-scale imager.Comment: 7 pages, 6 figure
Superconducting Nb-film LC resonator
Sputtered Nb thin-film LC resonators for low frequencies at 0.5 MHz have been
fabricated and tested in the temperature range 0.05--1 K in magnetic fields up
to 30 mT. Their Q value increases towards decreasing temperature as sqrt(T) and
reaches 10^3 at 0.05 K. As a function of magnetic field Q is unstable and
displays variations up to 50%, which are reproducible from one field sweep to
the next. These instabilities are attributed to dielectric losses in the plasma
deposited SiO_2 insulation layer, since the thin-film coil alone reaches a Q >
10^5 at 0.05 K.Comment: 6 pages, 7 figures, submitted to Review of Scientific Instrument
Evaluation of NV556, a Novel Cyclophilin Inhibitor, as a Potential Antifibrotic Compound for Liver Fibrosis
Hepatic fibrosis can result as a pathological response to nonalcoholic steatohepatitis (NASH). Cirrhosis, the late stage of fibrosis, has been linked to poor survival and an increased risk of developing hepatocellular carcinoma, with limited treatment options available. Therefore, there is an unmet need for novel effective antifibrotic compounds. Cyclophilins are peptidyl-prolyl cis-trans isomerases that facilitate protein folding and conformational changes affecting the function of the targeted proteins. Due to their activity, cyclophilins have been presented as key factors in several stages of the fibrotic process. In this study, we investigated the antifibrotic effects of NV556, a novel potent sanglifehrin-based cyclophilin inhibitor, in vitro and in vivo. NV556 potential antifibrotic effect was evaluated in two well-established animal models of NASH, STAM, and methionine-choline-deficient (MCD) mice, as well as in an in vitro 3D human liver ECM culture of LX2 cells, a human hepatic stellate cell line. We demonstrate that NV556 decreased liver fibrosis in both STAM and MCD in vivo models and decreased collagen production in TGFβ1-activated hepatic stellate cells in vitro. Taken together, these results present NV556 as a potential candidate for the treatment of liver fibrosis
Analysis of detector performance in a gigahertz clock rate quantum key distribution system
We present a detailed analysis of a gigahertz clock rate environmentally robust phase-encoded quantum key distribution (QKD) system utilizing several different single-photon detectors, including the first implementation of an experimental resonant cavity thin-junction silicon single-photon avalanche diode. The system operates at a wavelength of 850 nm using standard telecommunications optical fibre. A general-purpose theoretical model for the performance of QKD systems is presented with reference to these experimental results before predictions are made about realistic detector developments in this system. We discuss, with reference to the theoretical model, how detector operating parameters can be further optimized to maximize key exchange rates
Vietnam military service history and prostate cancer
BACKGROUND: Three decades after US and Australian forces withdrew from Vietnam, there has been much public interest in the health consequences of service in Vietnam. One controversial question is whether the risk of prostate cancer amongst Vietnam veterans is increased. This paper examines relationships between military history, family history and risk of prostate cancer in a population-based case control study. METHODS: Cases were selected from the Cancer Registry of Western Australia as incident cases of histologically-confirmed prostate cancer, and controls were age-matched and selected from the Western Australian electoral roll. Study participants were asked to report any military service history and details about that service. RESULTS: Between January 2001 and September 2002, 606 cases and 471 controls aged between 40–75 years were recruited. An increased prostate cancer risk was observed in men reporting they were deployed in Vietnam although this was not statistically significant (OR = 2.12; 95% CI 0.88–5.06). An increased risk was also observed in men reporting prostate cancer in fathers (OR = 1.90; 95% CI 1.20–3.00) or brothers (OR = 2.05; 95% CI 1.20–3.50) diagnosed with prostate cancer. CONCLUSION: These findings support a positive association between prostate cancer and military service history in the Vietnam war and a first degree relative family history of prostate cancer
Characterization of a fabrication process for the integration of superconducting qubits and RSFQ circuits
In order to integrate superconducting qubits with rapid-single-flux-quantum
(RSFQ) control circuitry, it is necessary to develop a fabrication process that
fulfills at the same time the requirements of both elements: low critical
current density, very low operating temperature (tens of milliKelvin) and
reduced dissipation on the qubit side; high operation frequency, large
stability margins, low dissipated power on the RSFQ side. For this purpose, VTT
has developed a fabrication process based on Nb trilayer technology, which
allows the on-chip integration of superconducting qubits and RSFQ circuits even
at very low temperature. Here we present the characterization (at 4.2 K) of the
process from the point of view of the Josephson devices and show that they are
suitable to build integrated superconducting qubits
CAG repeat length in the androgen receptor gene is related to age at diagnosis of prostate cancer and response to endocrine therapy, but not to prostate cancer risk
The length of the polymorphic CAG repeat in the N-terminal of the androgen receptor (AR) gene is inversely correlated with the transactivation function of the AR. Some studies have indicated that short CAG repeats are related to higher risk of prostate cancer. We performed a case–control study to investigate relations between CAG repeat length and prostate cancer risk, tumour grade, tumour stage, age at diagnosis and response to endocrine therapy. The study included 190 AR alleles from prostate cancer patients and 186 AR alleles from female control subjects. All were whites from southern Sweden. The frequency distribution of CAG repeat length was strikingly similar for cases and controls, and no significant correlation between CAG repeat length and prostate cancer risk was detected. However, for men with non-hereditary prostate cancer (n = 160), shorter CAG repeats correlated with younger age at diagnosis (P = 0.03). There were also trends toward associations between short CAG repeats and high grade (P = 0.07) and high stage (P = 0.07) disease. Furthermore, we found that patients with long CAG repeats responded better to endocrine therapy, even after adjusting for pretreatment level of prostate-specific antigen and tumour grade and stage (P = 0.05). We conclude that short CAG repeats in the AR gene correlate with young age at diagnosis of prostate cancer, but not with higher risk of the disease. Selection of patients with early onset prostate cancer in case–control studies could therefore lead to an over-estimation of the risk of prostate cancer for men with short CAG repeats. An association between long CAG repeats and good response to endocrine therapy was also found, but the mechanism and clinical relevance are unclear. © 1999 Cancer Research Campaig
Mycobacterium indicus pranii Supernatant Induces Apoptotic Cell Death in Mouse Peritoneal Macrophages In Vitro
Mycobacterium indicus pranii (MIP), also known as Mw, is a saprophytic, non-pathogenic strain of Mycobacterium and is commercially available as a heat-killed vaccine for leprosy and recently tuberculosis (TB) as part of MDT. In this study we provide evidence that cell-free supernatant collected from original MIP suspension induces rapid and enhanced apoptosis in mouse peritoneal macrophages in vitro. It is demonstrated that the MIP cell-free supernatant induced apoptosis is mitochondria-mediated and caspase independent and involves mitochondrial translocation of Bax and subsequent release of AIF and cytochrome c from the mitochondria. Experiments with pharmacological inhibitors suggest a possible role of PKC in mitochondria-mediated apoptosis of macrophages
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