As quantum coherence times of superconducting circuits have increased from nanoseconds to hundreds of microseconds, they are currently one of the leading platforms for quantum information processing. ...However, coherence needs to further improve by orders of magnitude to reduce the prohibitive hardware overhead of current error correction schemes. Reaching this goal hinges on reducing the density of broken Cooper pairs, so-called quasiparticles. Here, we show that environmental radioactivity is a significant source of nonequilibrium quasiparticles. Moreover, ionizing radiation introduces time-correlated quasiparticle bursts in resonators on the same chip, further complicating quantum error correction. Operating in a deep-underground lead-shielded cryostat decreases the quasiparticle burst rate by a factor fifty and reduces dissipation up to a factor four, showcasing the importance of radiation abatement in future solid-state quantum hardware.
We report on the results obtained with the global CUPID-0 background model, which combines the data collected in the two measurement campaigns for a total exposure of 8.82~kg\(\times\)yr of ...\(^{82}\)Se. We identify with improved precision the background sources within the 3 MeV energy region, where neutrinoless double \(\beta\)-decay of \(^{82}\)Se and \(^{100}\)Mo is expected, making more solid the foundations for the background budget of the next-generation CUPID experiment. Relying on the excellent data reconstruction, we measure the two-neutrino double \(\beta\)-decay half-life of \(^{82}\)Se with unprecedented accuracy: \(T_{1/2}^{2\nu} = 8.69 \pm 0.05 \textrm{(stat.)}~^{+0.09}_{-0.06} \textrm{(syst.)} \times 10^{19}~\textrm{yr}\).
Journal of Physics: Conference Series 2019 Kinetic Inductance Detectors (KIDs) are superconductive low$-$temperature
detectors useful for astrophysics and particle physics. We have developed
arrays ...of lumped elements KIDs (LEKIDs) sensitive to microwave photons,
optimized for the four horn-coupled focal planes of the OLIMPO balloon-borne
telescope, working in the spectral bands centered at 150 GHz, 250 GHz, 350 GHz,
and 460 GHz. This is aimed at measuring the spectrum of the Sunyaev-Zel'dovich
effect for a number of galaxy clusters, and will validate LEKIDs technology in
a space-like environment. Our detectors are optimized for an intermediate
background level, due to the presence of residual atmosphere and
room--temperature optical system and they operate at a temperature of 0.3 K.
The LEKID planar superconducting circuits are designed to resonate between 100
and 600 MHz, and to match the impedance of the feeding waveguides; the measured
quality factors of the resonators are in the $10^{4}-10^{5}$ range, and they
have been tuned to obtain the needed dynamic range. The readout electronics is
composed of a $cold$ $part$, which includes a low noise amplifier, a
dc$-$block, coaxial cables, and power attenuators; and a $room-temperature$
$part$, FPGA$-$based, including up and down-conversion microwave components (IQ
modulator, IQ demodulator, amplifiers, bias tees, attenuators). In this
contribution, we describe the optimization, fabrication, characterization and
validation of the OLIMPO detector system.
Heat shock proteins are intracellular proteins associated with a generalized response of cells to stress. The purpose of this study was to assess RNA levels of heat shock protein 70 and 90 in fed or ...fasted rat livers during ischemia-reperfusion. Northern blot analysis of heat shock proteins was performed. Adenosine triphosphate and glutathione were assessed. In baseline conditions, livers of fasted rats showed a twofold increase in mRNA for both heat shock proteins and 38% and 43% reductions in adenosine triphosphate and glutathione, respectively, when compared with organs from fed rats. After ischemia, livers of fasted rats presented a twofold decrease in heat shock protein mRNA, while no changes were observed in livers of fed rats; reduced glutathione and adenosine triphosphate decreased 55% and 50% in fasted livers and 25% and 20% in fed organs, respectively. After 120 min of reperfusion, heat shock protein mRNA rose threefold in fasted livers, while a slight decrease was observed in the fed group; reduced glutathione and adenosine triphosphate returned to 65% and 70% of baseline values in fasted livers and 85% and 90% in fed organs, respectively. In conclusion, the nutritional status affects heat shock protein expression determined by reperfusion. The reduced antioxidant status leading to increased oxidative stress could be the mechanism underlying the phenomenon.
When we apply an AC current to a superconductor, the Cooper pairs oscillate and acquire kinetic inductance, that can be measured by inserting the superconductor in a LC circuit with high merit ...factor. Interactions in the superconductor can break the Cooper pairs,causing sizable variations in the kinetic inductance and, thus, the response of the LC circuit. This concept is at the basis of Kinetic Inductance Detectors (KIDs). The CALDER project aims to develope high sensitivity, cryogenic light detectors using KIDs in combination with a silicon absorber to cover, via phonon mediation, an area of several cm2 1. This contribution focuses on the development of a low-noise, digital and analogical,electronics for the sensor's readout and on the design and testing of a new geometry for the superconductive resonator to improve detector sensitivity.
We report on the performance of lumped--elements Kinetic Inductance Detector (KID) arrays for mm and sub--mm wavelengths, operated at 0.3K during the stratospheric flight of the OLIMPO payload, at an ...altitude of 37.8 km. We find that the detectors can be tuned in-flight, and their performance is robust against radiative background changes due to varying telescope elevation. We also find that the noise equivalent power of the detectors in flight is significantly reduced with respect to the one measured in the laboratory, and close to photon-noise limited performance. The effect of primary cosmic rays crossing the detector is found to be consistent with the expected ionization energy loss with phonon-mediated energy transfer from the ionization sites to the resonators. In the OLIMPO detector arrays, at float, cosmic ray events affect less than 4% of the detector samplings for all the pixels of all the arrays, and less than 1% of the samplings for most of the pixels. These results are also representative of what one can expect from primary cosmic rays in a satellite mission with similar KIDs and instrument environment.
The events implicated in the early phases of acute ethanol-induced hepatocyte injury and their relation with the nutritional status of the liver are not clearly defined. We aimed to determine the ...effect of ethanol on ATP and cytosolic free Ca2+ in hepatocytes isolated from fed or fasted rats. Cell injury was assessed by LDH release and trypan blue uptake, ATP by 31PNMR spectroscopy, and cytosolic free Ca2+ with aequorin. In control conditions, cells from fasted animals had a lower ATP level (-52%) and a higher cytosolic free Ca2+ (+101%) than did those isolated from fed animals. Ethanol caused a dose-dependent cell injury in both groups. At all ethanol doses, greater, damage occurred when using hepatocytes isolated from fasted rats. In both groups, a dose-dependent decrease in ATP content and a rise in cytosolic free Ca2+ were seen. The magnitude of these changes were significantly greater in the fasted group. In conclusion, these data showed that fasting affects the energy status and cytosolic free calcium level in hepatocytes; ethanol causes a dose-dependent cell injury that occurs in association with a fall in ATP and a rise in cytosolic free Ca2+ levels. The nutritional status of an animals is an important determinant of the severity of ethanol-induced damage to liver cells.
Fetal alcohol syndrome usually implies effects on the offspring of maternal EtOH consumption during gestation, with fewer reports addressing the impact of paternal exposure on the progeny. One ...previous report has dealt with the impact of EtOH exposure on peripubertal male rats as a model of teenage drinking and the deleterious effects on the offspring. We report here findings examining the effect of 2 mo of EtOH feeding on male animals as they progressed through puberty on their ability to impregnate EtOH-naive female rats and characteristics of the subsequent litters. The EtOH-imbibing fathers weighed significantly less than pairfed controls and animals ingesting a non-EtOH liquid diet ad libitum. Nevertheless, they were able to mate successfully, although fecundity was significantly reduced. The number of successful pregnancies, defined as carried to term, was diminished from 92% in controls to 75% in EtOH-fed animals (p < 0.05). There was increased paternal testicular oxidative injury demonstrated by enhanced lipid peroxidation, protein oxidation, and decreased ratio of reduced to oxidized glutathione. The litter size of the EtOH-exposed males was reduced by 46%. The average litter size was 12.4+/-1.5 pups/litter in ad libitum animals, virtually identical to the 12.5+/-0.6 pups/litter in the pair fed controls. This is in sharp contrast to the 6.7+/-0.1 pups/litter from the paternal EtOH matings (p < 0.001). There was an increase in the average individual weight of pup offspring of paternally EtOH-exposed animals (p < 0.01 vs pair-fed controls and p < 0.05 vs ad libitum). Curiously, the male-to-female pup ratio was altered with a higher preponderance of male offspring from EtOH-fed fathers. There were no gross malformations noted among the pups. Insulin-like growth factor-1 levels in the pups at 10 d of age were unaltered between the groups. However, leptin was significantly elevated in the EtOH offspring. It appears that chronic EtOH exposure in the peripubertal fathers subsequently decreases fecundity and that this may be mediated by testicular oxidative injury, perhaps leading to accelerated germ cell apoptosis.
