95 research outputs found
Short-term efficacy and safety of second generation bipolar transurethral vaporization of the prostate (B-TUVP) for large benign prostate enlargement: Results from a retrospective feasibility study
BackgroundTo investigate the efficacy and safety of a second-generation bipolar transurethral electro vaporization of the prostate (B-TUVP) with the new oval-shaped electrode for large benign prostatic enlargement (BPE) with prostate volume (PV) â„100ml.Materials and methods100 patients who underwent second-generation B-TUVP with the oval-shaped electrode for male lower urinary tract symptom (LUTS) or urinary retention between July 2018 and July 2020 were enrolled in this study. The patientsâ characteristics and treatment outcome were retrospectively compared between patients with PV <100ml and â„100ml.Results17/41 (41.5%) cases of PV â„100ml and 24/59 cases (40.7%) of PV <100ml were catheterised due to urinary retention. The duration of post-operative catheter placement and hospital-stay of PV â„100ml (3.1±1.3 and 5.6±2.3 days) were not different from PV <100ml (2.7±1.2 and 5.0±2.4 days). In uncatheterised patients (N = 59), post-void residual urine volume (PVR) significantly decreased after surgery in both groups, however, maximum uroflow rate (Qmax) significantly increased after surgery only in PV <100ml but not in PV â„100ml. Voiding symptoms and patientsâ QoL derived from International Prostate Symptom Score (IPSS), IPSS-QoL (IPSS Quality of Life Index) and BPH Impact Index (BII) scores, significantly improved after B-TUVP in both groups. Catheter free status after final B-TUVP among patients with preoperative urinary retention was achieved in 18/24 (75.0%) and 14/17 (82.1%) cases in patient with <100ml and â„100ml, respectively. There was no significant difference in post-operative Hb after B-TUVP, which was 97.0±5.4% of baseline for PV <100ml and 96.9±6.1% for PV â„100ml and no TUR syndrome was observed.ConclusionsThis is the first study investigating short-term efficacy and safety of second-generation B-TUVP with the oval-shaped electrode on large BPE. B-TUVP appears to be effective and safe for treating moderate-to-severe lower urinary tract symptoms and urinary retention in patients with large BPE
Search for Cosmic-ray Boosted Sub-GeV Dark Matter using Recoil Protons at Super-Kamiokande
We report a search for cosmic-ray boosted dark matter with protons using the
0.37 megatonyears data collected at Super-Kamiokande experiment during
the 1996-2018 period (SKI-IV phase). We searched for an excess of proton
recoils above the atmospheric neutrino background from the vicinity of the
Galactic Center. No such excess is observed, and limits are calculated for two
reference models of dark matter with either a constant interaction
cross-section or through a scalar mediator. This is the first experimental
search for boosted dark matter with hadrons using directional information. The
results present the most stringent limits on cosmic-ray boosted dark matter and
exclude the dark matter-nucleon elastic scattering cross-section between
and for dark matter mass
from 10 MeV/ to 1 GeV/.Comment: With 1-page appendi
Search for Periodic Time Variations of the Solar B Neutrino Flux Between 1996 and 2018 in Super-Kamiokande
We report a search for time variations of the solar B neutrino flux using
5,804 live days of Super-Kamiokande data collected between May 31, 1996, and
May 30, 2018. Super-Kamiokande measured the precise time of each solar neutrino
interaction over 22 calendar years to search for solar neutrino flux
modulations with unprecedented precision. Periodic modulations are searched for
in a data set comprised of five-day interval solar neutrino flux measurements
with a maximum likelihood method. We also applied the Lomb-Scargle method to
this data set to compare it with previous reports. The only significant
modulation found is due to the elliptic orbit of the Earth around the Sun. The
observed modulation is consistent with astronomical data: we measured an
eccentricity of (1.530.35)\,\%, and a perihelion shift is
(1.513.5)\,days.Comment: 8 pages, 5 figures, 2 tables, and data file:
"sksolartimevariation5804d.txt
Measurement of the cosmogenic neutron yield in Super-Kamiokande with gadolinium loaded water
Cosmic-ray muons that enter the Super-Kamiokande detector cause hadronic
showers due to spallation in water, producing neutrons and radioactive
isotopes. Those are a major background source for studies of MeV-scale
neutrinos and searches for rare events. Since 2020, gadolinium was introduced
in the ultra-pure water in the Super-Kamiokande detector to improve the
detection efficiency of neutrons. In this study, the cosmogenic neutron yield
was measured using data acquired during the period after the gadolinium
loading. The yield was found to be at
259 GeV of average muon energy at the Super-Kamiokande detector.Comment: 10 pages, 10 figures, 3 table
Search for astrophysical electron antineutrinos in Super-Kamiokande with 0.01wt% gadolinium-loaded water
We report the first search result for the flux of astrophysical electron
antineutrinos for energies O(10) MeV in the gadolinium-loaded Super-Kamiokande
(SK) detector. In June 2020, gadolinium was introduced to the ultra-pure water
of the SK detector in order to detect neutrons more efficiently. In this new
experimental phase, SK-Gd, we can search for electron antineutrinos via inverse
beta decay with efficient background rejection and higher signal efficiency
thanks to the high efficiency of the neutron tagging technique. In this paper,
we report the result for the initial stage of SK-Gd with a exposure at 0.01% Gd mass concentration. No significant excess
over the expected background in the observed events is found for the neutrino
energies below 31.3 MeV. Thus, the flux upper limits are placed at the 90%
confidence level. The limits and sensitivities are already comparable with the
previous SK result with pure-water () owing
to the enhanced neutron tagging
Diffuse supernova neutrino background search at Super-Kamiokande
A new search for the diffuse supernova neutrino background (DSNB) flux has
been conducted at Super-Kamiokande (SK), with a -ktonday
exposure from its fourth operational phase IV. The new analysis improves on the
existing background reduction techniques and systematic uncertainties and takes
advantage of an improved neutron tagging algorithm to lower the energy
threshold compared to the previous phases of SK. This allows for setting the
world's most stringent upper limit on the extraterrestrial flux,
for neutrino energies below 31.3 MeV. The SK-IV results are combined with the
ones from the first three phases of SK to perform a joint analysis using
ktondays of data. This analysis has the world's best
sensitivity to the DSNB flux, comparable to the predictions from
various models. For neutrino energies larger than 17.3 MeV, the new combined
C.L. upper limits on the DSNB flux lie around
cm, strongly disfavoring the most optimistic
predictions. Finally, potentialities of the gadolinium phase of SK and the
future Hyper-Kamiokande experiment are discussed.Comment: 42 pages, 37 figures, 14 table
Searching for supernova bursts in Super-Kamiokande IV
Super-Kamiokande has been searching for neutrino bursts characteristic of core-collapse supernovae continuously, in real time, since the start of operations in 1996. The present work focuses on detecting more distant supernovae whose event rate may be too small to trigger in real time, but may be identified using an offline approach. The analysis of data collected from 2008 to 2018 found no evidence of distant supernovae bursts. This establishes an upper limit of 0.29 yrâ1 on the rate of core-collapse supernovae out to 100 kpc at 90% C.L. For supernovae that fail to explode and collapse directly to black holes the limit reaches to 300 kpc
Search for neutrinos in coincidence with gravitational wave events from the LIGOâVirgo O3a observing run with the Super-Kamiokande detector
The Super-Kamiokande detector can be used to search for neutrinos in time coincidence with gravitational waves detected by the LIGOâVirgo Collaboration (LVC). Both low-energy (7â100 MeV) and high-energy (0.1â105 GeV) samples were analyzed in order to cover a very wide neutrino spectrum. Follow-ups of 36 (out of 39) gravitational waves reported in the GWTC-2 catalog were examined; no significant excess above the background was observed, with 10 (24) observed neutrinos compared with 4.8 (25.0) expected events in the high-energy (low-energy) samples. A statistical approach was used to compute the significance of potential coincidences. For each observation, p-values were estimated using neutrino direction and LVC sky map; the most significant event (GW190602_175927) is associated with a post-trial p-value of 7.8% (1.4Ï). Additionally, flux limits were computed independently for each sample and by combining the samples. The energy emitted as neutrinos by the identified gravitational wave sources was constrained, both for given flavors and for all flavors assuming equipartition between the different flavors, independently for each trigger and by combining sources of the same nature
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