We present an improved search for neutrinoless double-beta (0νββ) decay of ^{136}Xe in the KamLAND-Zen experiment. Owing to purification of the xenon-loaded liquid scintillator, we achieved a ...significant reduction of the ^{110m}Ag contaminant identified in previous searches. Combining the results from the first and second phase, we obtain a lower limit for the 0νββ decay half-life of T_{1/2}^{0ν}>1.07×10^{26} yr at 90% C.L., an almost sixfold improvement over previous limits. Using commonly adopted nuclear matrix element calculations, the corresponding upper limits on the effective Majorana neutrino mass are in the range 61-165 meV. For the most optimistic nuclear matrix elements, this limit reaches the bottom of the quasidegenerate neutrino mass region.
ABSTRACT In the late stages of nuclear burning for massive stars (M > 8 M ), the production of neutrino-antineutrino pairs through various processes becomes the dominant stellar cooling mechanism. As ...the star evolves, the energy of these neutrinos increases and in the days preceding the supernova a significant fraction of emitted electron anti-neutrinos exceeds the energy threshold for inverse beta decay on free hydrogen. This is the golden channel for liquid scintillator detectors because the coincidence signature allows for significant reductions in background signals. We find that the kiloton-scale liquid scintillator detector KamLAND can detect these pre-supernova neutrinos from a star with a mass of 25 M at a distance less than 690 pc with 3 significance before the supernova. This limit is dependent on the neutrino mass ordering and background levels. KamLAND takes data continuously and can provide a supernova alert to the community.
We present the results of a search for extraterrestrial electron antineutrinos (v sub(e)'s) in the energy range 8.3 MeV < Ev sub(e) < 31.8 MeV using the KamLAND detector. In an exposure of 4.53 ...kton-year, we identify 25 candidate events. All of the candidate events can be attributed to background, most importantly neutral current atmospheric neutrino interactions, setting an upper limit on the probability of super(8)B solar converting into v sub(e)'s at 5.3 x 10 super(-5) (90% CL), if we assume an undistorted v sub(e) shape. This limit corresponds to a solar v sub(e) flux of 93 cm super(-2) s super(-1) or an event rate of 1.6 events (kton - year) super(-1) above the energy threshold Ev sub(e) > or =, slanted 8.3 MeV. The present data also allows us to set more stringent limits on the diffuse supernova neutrino flux and on the annihilation rates for light dark matter particles.
Strategic planning for coronavirus disease (COVID-19) care has dominated the agenda of medical services, which have been further restricted by the need for minimizing viral transmission. Risk is ...particularly relevant in relation to endoscopy procedures. This study aimed to describe a contingency plan for a tertiary academic cancer center, define a strategy to prioritize and postpone examinations, and evaluate the infection rate among healthcare workers (HCWs) in the endoscopy unit of the Cancer Institute of the State of São Paulo (ICESP).
We created a strategy to balance the risk of acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and to mitigate the effects of postponing endoscopic procedures in oncological patients. A retrospective analysis of prospectively collected data on all endoscopies between March and June 2020 compared with those during the same period in 2019 was carried out. All HCWs were interviewed to obtain clinical data and SARS-CoV-2 test results.
During the COVID-19 outbreak, there was a reduction of 55% in endoscopy cases in total. Colonoscopy was the most affected modality. The total infection rate among all HCWs was 38%. None of the senior digestive endoscopists had COVID-19. However, all bronchoscopists had been infected. One of three fellows had a serological diagnosis of COVID-19. Two-thirds of all nurses were infected, whereas half of all technicians were infected.
In this pandemic scenario, all endoscopy services must prioritize the procedures that will be performed. It was possible to maintain some endoscopic procedures, including those meant to provide nutritional access, tissue diagnosis, and endoscopic resection. Personal protective equipment (PPE) seems effective in preventing transmission of COVID-19 from patients to digestive endoscopists. These measures can be useful in planning, even for pandemics in the future.
Some values of the coincidence search in Section 3 were not correct in the published article. The time differences of the closest event to GW150915, GW151226, and LVT151012 are 1.9 h, 5.7 h, and 1017 ...s, respectively. The energies of the closest event are 2.07 MeV, 2.67 MeV, and 1.41 MeV, respectively. Figures 1, 2, and 3 were not correct in the published article. The corrected figures are provided here.
To examine the effects of instant coffee consumption on cancer risk, we analyzed the oxidative DNA damage levels and the DNA repair and redox systems in the livers of coffee-fed mice. Three-week-old ...male ICR mice were fed with/without 0.1% (w/v) instant coffee solution. At 2, 4, and 8 mo, the levels of 8-hydroxydeoxyguanosine (8-OH-dG), a major form of oxidative DNA damage, and the expression of mouse 8-OH-dG repair-associated genes and redox system-associated genes, the SOD activity, and the LPO level were analyzed. Simultaneously, half of the mice were fed a low vitamin (LV) diet (autoclaved diet) to disturb the defense system against oxidative stresses. As a result, the 8-OH-dG level was increased in the livers of LV diet (+ water)-fed mice for 8 mo, in comparison to those of the 0 M control mice and normal diet (+ water)-fed mice. However, no significant differences between water drinking and coffee drinking were observed, in terms of the 8-OH-dG level. In addition, the 8-OH-dG repair-associated gene expression, the SOD activity, and the LPO level also showed no significant differences between water drinking and coffee drinking in all mouse groups. On the other hand, among the redox system-associated genes, only the expression of GPx1 was changed. These results suggest that instant coffee consumption has little, if any, effect on the risk of liver cancer due to oxidative stresses.
Earthworms and soil pollutants Hirano, Takeshi; Tamae, Kazuyoshi
Sensors,
12/2011, Volume:
11, Issue:
12
Journal Article, Book Review
Peer reviewed
Open access
Although the toxicity of metal contaminated soils has been assessed with various bioassays, more information is needed about the biochemical responses, which may help to elucidate the mechanisms ...involved in metal toxicity. We previously reported that the earthworm, Eisenia fetida, accumulates cadmium in its seminal vesicles. The bio-accumulative ability of earthworms is well known, and thus the earthworm could be a useful living organism for the bio-monitoring of soil pollution. In this short review, we describe recent studies concerning the relationship between earthworms and soil pollutants, and discuss the possibility of using the earthworm as a bio-monitoring organism for soil pollution.
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