We search for energetic electron recoil signals induced by boosted dark matter (BDM) from the galactic center using the COSINE-100 array of NaI(Tl) crystal detectors at the Yangyang Underground ...Laboratory. The signal would be an excess of events with energies above 4 MeV over the well-understood background. Because no excess of events are observed in a 97.7 kg·yr exposure, we set limits on BDM interactions under a variety of hypotheses. Notably, we explored the dark photon parameter space, leading to competitive limits compared to direct dark photon search experiments, particularly for dark photon masses below 4 MeV and considering the invisible decay mode. Furthermore, by comparing our results with a previous BDM search conducted by the Super-Kamionkande experiment, we found that the COSINE-100 detector has advantages in searching for low-mass dark matter. This analysis demonstrates the potential of the COSINE-100 detector to search for MeV electron recoil signals produced by the dark sector particle interactions.
Abstract
Here, we developed a new approach to synthesize NiCo
2
S
4
thin films for supercapacitor application using the successive ionic layer adsorption and reaction (SILAR) method on Ni mesh with ...different molar ratios of Ni and Co precursors. The five different NiCo
2
S
4
electrodes affect the electrochemical performance of the supercapacitor. The NiCo
2
S
4
thin films demonstrate superior supercapacitance performance with a significantly higher specific capacitance of 1427 F g
−1
at a scan rate of 20 mV s
−1
. These results indicate that ternary NiCo
2
S
4
thin films are more effective electrodes compared to binary metal oxides and metal sulfides.
We have developed ultra-low-background NaI(Tl) crystals to reproduce the DAMA results with the ultimate goal of achieving purity levels that are comparable to or better than those of the DAMA/LIBRA ...crystals. Even though the achieved background level does not approach that of DAMA/LIBRA, it is crucial to have a quantitative understanding of the backgrounds. We have studied background simulations toward a deeper understanding of the backgrounds and developed background models for a 9.16-kg NaI(Tl) crystal used in the test arrangement. In this paper we describe the contributions of background sources quantitatively by performing Geant4 Monte Carlo simulations that are fitted to the measured data to quantify the unknown fractions of the background compositions. In the fitted results, the overall simulated background spectrum well describes the measured data with a 9.16-kg NaI(Tl) crystal and shows that the background sources are dominated by surface
210
Pb and internal
40
K in the 2–6-keV energy interval, which produce 2.4 counts/day/keV/kg (dru) and 0.5 dru, respectively.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A search for inelastic boosted dark matter (IBDM) using the COSINE-100 detector with 59.5 days of data is presented. This relativistic dark matter is theorized to interact with the target material ...through inelastic scattering with electrons, creating a heavier state that subsequently produces standard model particles, such as an electron-positron pair. In this study, we search for this electron-positron pair in coincidence with the initially scattered electron as a signature for an IBDM interaction. No excess over the predicted background event rate is observed. Therefore, we present limits on IBDM interactions under various hypotheses, one of which allows us to explore an area of the dark photon parameter space that has not yet been covered by other experiments. This is the first experimental search for IBDM using a terrestrial detector.
Observation of growing phase space density (PSD) peak in the outer electron radiation belt has been considered evidence for local wave‐driven acceleration as a primary cause of radiation belt ...enhancement. However, recent studies showed that strong substorm‐associated MeV electron injections can also cause significant radiation belt enhancements on fast timescales (∼10s min). Such rapid enhancements pose challenges for determining true spatial PSD profiles. To address this, we conduct a detailed spatiotemporal analysis of electron flux and PSD during an enhancement event, using Van Allen Probes data. Our analysis reveals rapid and intermittent flux enhancements. During these rapid enhancements, inbound spacecraft observed false PSD peaks, due to spacecraft's relatively slow movement. However, we identify time intervals of stable fluxes between enhancements, enabling us to determine quasi‐stationary PSD profiles with no noticeable peaks. This study provides new insights into accurate PSD analysis, critical for understanding the mechanisms underlying radiation belt enhancements.
Plain Language Summary
Radiation belt physics studies the origin and dynamics of high‐energy electrons trapped in the Earth's radiation belts. The radial profiles of these electrons' phase space density (PSD) are essential parameters for investigating their origin and dynamics. Outward‐increasing PSD profiles indicate that electrons have been transported radially (injections) from outside the radiation belt, while locally peaked profiles suggest that they were generated locally within the belt. Obtaining accurate PSD profiles is challenging due to significant temporal changes in electron flux, particularly rapid flux enhancements from injections as observed in recent studies. To examine the impact of rapid flux enhancements on PSD analysis, we closely tracked electron flux changes in space and time during an enhancement event using data from NASA's Van Allen Probes. Our results show that inbound spacecraft can observe falsely peaked PSD profiles during rapid flux enhancements, which are temporal artifacts from relatively slower spacecraft motion. By identifying time intervals of stable electron flux between enhancements, we were able to determine the true spatial PSD profiles, which overall exhibited outward‐increasing trends, consistent with injections. Our findings offer new perspective on accurately determining PSD radial profiles, which is essential for unraveling the origins of high‐energy electrons in the Earth's radiation belts.
Key Points
Rapid and intermittent electron enhancement pattern significantly impacts phase space density (PSD) analysis
Inbound spacecraft can observe a temporal PSD peak during rapid electron enhancements driven by injections
Quasi‐stationary time intervals between enhancements enable accurate determination of PSD radial profiles
The objective of this study was to evaluate the validity and clinical impact of positron emission tomography (PET) or positron emission tomography/computed tomography (PET/CT) using ...18-fluoro-2-deoxy-D-glucose in the posttherapy surveillance of patients with endometrial carcinoma. Eighty-eight patients previously treated for histopathologically diagnosed endometrial adenocarcinoma underwent 99 PET or PET/CT scans at follow-up visits at Asan Medical Center, Seoul, Korea, between 2001 and 2007. The standard of reference for tumor recurrence consisted of histopathologic confirmation or follow-up information at least 6 months after PET or PET/CT. Of the 88 patients, 24 underwent PET (n = 11) and/or PET/CT (n = 14) scans due to suspected disease recurrence. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of PET and/or PET/CT in detecting recurrence in these patients were 100%, 83.3%, 96%, 95%, and 100%, respectively. Especially, PET/CT revealed true-positive findings in three patients with elevated tumor markers but negative CT findings. The remaining 64 patients underwent PET (n = 8) and/or PET/CT (n = 66) as part of routine posttherapy surveillance; these patients were asymptomatic, with no evidence of disease. The sensitivity, specificity, accuracy, PPV, and NPV of PET and/or PET/CT in detecting recurrence in these patients were all 100%. Clinical decisions on treatment were changed in 14 (21.9%) patients by introducing PET or PET/CT into their conventional posttherapy surveillance program. PET and/or PET/CT were highly effective in discriminating true recurrence in patients with suspected recurrence, highly sensitive in detecting recurrence in asymptomatic patients, and had impacts on clinical decisions in a considerable portion of patients.
Abstract Purpose Studies regarding the effects of aesthetic outcomes after breast cancer surgery on quality of life (QoL) have yielded inconsistent results. This study analyzed the aesthetic outcomes ...and QoL of women who underwent breast conserving surgery (BCS) or total mastectomy with immediate reconstruction (TMIR) using objective and validated methods. Patients and methods QoL questionnaires (EORTC QLQ-C30, BR23, and HADs) were administered at least 1 year after surgery and adjuvant therapy to 485 patients who underwent BCS, 46 who underwent TMIR, and 87 who underwent total mastectomy (TM) without reconstruction. Aesthetic results were evaluated using BCCT.core software and by a panel of physicians. Patients' body image perception was assessed using the body image scale (BIS). Results QoL outcomes, including for social and role functioning, fatigue, pain, body image, and arm symptoms, were significantly better in the BCS and TMIR groups than in the TM group (p<0.05 each). BIS was significantly better in the BCS than in the TM or TMIR group (p<0.001 each). In the BCS and TMIR groups, general QoL factors were not significantly associated with objective cosmetic outcomes, except for body image in the QLQ-BR23. In contrast, patients with poorer BIS score reported lower QoL in almost all items of the QLQ-C30, BR23, and HADS (p<0.05 each). Conclusion In conclusion, BCS and TMIR enhanced QoL compared with TM. Among BCS and TMIR patients, objectively measured cosmetic results did not affect general QoL. S elf-perception of body image seems to be more important for QoL after breast cancer surgery.
Summary
This systematic review was performed to compare the diagnostic accuracy of vertebral fracture assessment (VFA) with that of spinal radiography for identification of vertebral fractures (VFs). ...VFA appeared to have moderate sensitivity and high specificity for detecting VFs when compared with spinal radiography.
Introduction
VFs are recognized as the hallmark of osteoporosis, and a previous VF increases the risk of a future fracture. Therefore, the timely detection of VFs is important for prevention of further fractures. This systematic review examined the diagnostic accuracy of VFA using dual X-ray absorptiometry (DXA) to identify VFs.
Methods
We searched for potentially relevant studies using electronic databases, including Ovid-Medline, Ovid-EMBASE, Cochrane library, and four Korean databases, from their inception to May 2013. We compared the diagnostic accuracy of VFA with that of spinal radiography for detection of VFs by analyzing the sensitivity and specificity using a 2 × 2 contingency table. Subgroup analyses were also performed on studies with a low risk of bias and applicability.
Results
Twelve studies were analyzed for the diagnostic accuracy of VFA. The sensitivity and specificity were 0.70–0.93 and 0.95–1.00, respectively, analyzed on a per-vertebra basis, and 0.65–1.00 and 0.74–1.00 on a per-patient basis. The sensitivity and specificity of five studies in subgroups with a low risk of bias in the intervention test were 0.70–0.84 and 0.96–0.99, respectively. In studies with a low risk of bias in the patient selection, those based on a per-vertebra basis in three studies were 0.70–0.93 and 0.96–1.00, respectively.
Conclusions
VFA had moderate sensitivity and high specificity for detecting VF when compared with spinal radiography. However, the present findings are insufficient to assess whether spinal radiography should be replaced by VFA.
Summary
Background
It remains unclear whether initial compact lipiodol uptake after transarterial chemoembolisation (TACE) is associated with improved survival in patients with hepatocellular ...carcinoma (HCC).
Aim
To reveal the clinical relevance of compact lipiodolisation after TACE.
Methods
We studied 490 patients with unresectable HCC who had first been treated with TACE. Compact lipiodolisation was defined as the absence of an arterial enhancing lesion, reflecting complete lipiodol uptake, as assessed by dynamic computed tomography (CT) 1 month after treatment. The rate of initial compact lipiodolisation was analysed according to multiplicity and size of tumour, and survival of patients who achieved compact lipiodolisation was compared to that of patients who did not.
Results
Of the 490 patients, 409 (83.5%) were in Child–Pugh class A and 81 (16.5%) in class B. The rate of initial compact lipiodolisation in single HCCs was higher than that in multinodular HCCs (33.7% vs. 14.6%, P < 0.001). Among single HCCs, the rate of compact lipiodolisation in tumours ≤5, 5–10 and >10 cm was 46.6%, 13.6%, and 0% respectively. The 1‐, 3‐ and 5‐year survival rates of patients with compact uptake were 92.7%, 70.7% and 52.4% compared to 60.8%, 28.0% and 16.9% in patients with noncompact lipiodolisation. Multivariate analysis revealed that Child–Pugh class, alpha‐fetoprotein level, tumour node metastasis stage, portal vein thrombosis and initial compact lipiodolisation were independent predictors of survival.
Conclusions
Initial compact lipiodol uptake after transarterial chemoembolisation is associated with improved survival in patients with unresectable hepatocellular carcinoma. Accordingly, initial complete lipiodolisation should be considered a relevant therapeutic target.
Abstract Background Hyperglycemia occurs frequently after kidney transplantation and may be reversed when the dosage of the immunosuppressive agents is tapered. However, the effect of transient ...post-transplantation hyperglycemia (PTH) on transplantation outcomes is not well described. Methods Kidney transplant recipients without diabetes who underwent kidney transplantation between 2001 and 2012 were enrolled in the study. Transient PTH was defined as recovery from PTH without further antidiabetic therapy and the maintenance of glycated hemoglobin levels <6.5% at 1 year after transplantation. Persistent PTH until 1 year after transplantation was considered to be new-onset diabetes after transplantation (NODAT). The factors associated with increased risk of PTH were analyzed. We compared the development of diabetes mellitus, cardiovascular disease, and other transplantation outcomes among patients with no PTH, transient PTH, and NODAT. Results Among 176 kidney transplant recipients, 106 (60.2%) developed PTH and 58 (54.7%) of 106 patients with PTH had transient PTH. Older age, high body mass index (BMI), and female gender were independent risk factors for transient PTH. The incidence of diabetes was not significantly different between patients with no PTH and those with transient PTH. The incidence of cardiovascular disease was significantly increased in NODAT group compared with that in no PTH and transient PTH groups. However, the incidences of acute rejection, allograft loss, and patient death were comparable among the three groups. Conclusions Transient hyperglycemia after kidney transplantation was found to be associated with older age, high body mass index, and female gender. Transient elevation of blood glucose level did not affect post-transplantation outcomes, including diabetes mellitus and cardiovascular disease. However, patients with NODAT should be carefully monitored for the occurrence of cardiovascular disease.
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