76 research outputs found

    Measurement of the Background Activities of a 100Mo-enriched powder sample for AMoRE crystal material using a single high purity germanium detector

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    The Advanced Molybdenum-based Rare process Experiment (AMoRE) searches for neutrino-less double-beta (0{\nu}\b{eta}\b{eta}) decay of 100Mo in enriched molybdate crystals. The AMoRE crystals must have low levels of radioactive contamination to achieve low background signals with energies near the Q-value of the 100Mo 0{\nu}\b{eta}\b{eta} decay. To produce low-activity crystals, radioactive contaminants in the raw materials used to form the crystals must be controlled and quantified. 100EnrMoO3 powder, which is enriched in the 100Mo isotope, is of particular interest as it is the source of 100Mo in the crystals. A high-purity germanium detector having 100% relative efficiency, named CC1, is being operated in the Yangyang underground laboratory. Using CC1, we collected a gamma spectrum from a 1.6-kg 100EnrMoO3 powder sample enriched to 96.4% in 100Mo. Activities were analyzed for the isotopes 228Ac, 228Th, 226Ra, and 40K. They are long-lived naturally occurring isotopes that can produce background signals in the region of interest for AMoRE. Activities of both 228Ac and 228Th were < 1.0 mBq/kg at 90% confidence level (C.L.). The activity of 226Ra was measured to be 5.1 \pm 0.4 (stat) \pm 2.2 (syst) mBq/kg. The 40K activity was found as < 16.4 mBq/kg at 90% C.L.Comment: 20 pages, 6 figures, 5 table

    Measurement of the Background Activities of a 100Mo-enriched Powder Sample for an AMoRE Crystal Material by using Fourteen High-Purity Germanium Detectors

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    The Advanced Molybdenum-based Rare process Experiment in its second phase (AMoRE-II) will search for neutrinoless double-beta (0{\nu}\b{eta}\b{eta}) decay of 100Mo in 200 kg of molybdate crystals. To achieve the zero-background level in the energy range of the double-beta decay Q-value of 100Mo, the radioactive contamination levels in AMoRE crystals should be low. 100EnrMoO3 powder, which is enriched in the 100Mo isotope, is used to grow the AMoRE crystals. A shielded array of fourteen high-purity germanium detectors with 70% relative efficiency each was used for the measurement of background activities in a sample of 9.6-kg powder. The detector system named CAGe located at the Yangyang underground laboratory was designed for measuring low levels of radioactivity from natural radioisotopes or cosmogenic nuclides such as 228Ac, 228Th, 226Ra, 88Y, and 40K. The activities of 228Ac and 228Th in the powder sample were 0.88 \pm 0.12 mBq/kg and 0.669 \pm 0.087 mBq/kg, respectively. The activity of 226Ra was measured to be 1.50 \pm 0.23 mBq/kg. The activity of 88Y was 0.101 \pm 0.016 mBq/kg. The activity of 40K was found as 36.0 \pm 4.1 mBq/kg.Comment: 24 pages, 10 figures, 5 table

    Development and validation of the VitaL CLASS score to predict mortality in stage IV solid cancer patients with septic shock in the emergency department: a multi-center, prospective cohort study

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    Background Clinical decision-making of invasive high-intensity care for critically ill stage IV cancer patients in the emergency department (ED) is challenging. A reliable and clinically available prognostic score for advanced cancer patients with septic shock presented at ED is essential to improve the quality of intensive care unit care. This study aimed to develop a new prognostic score for advanced solid cancer patients with septic shock available early in the ED and to compare the performance to the previous severity scores. Methods This multi-center, prospective cohort study included consecutive adult septic shock patients with stage IV solid cancer. A new scoring system for 28-day mortality was developed and validated using the data of development (January 2016 to December 2017; n = 469) and validation sets (January 2018 to June 2019; n = 428). The developed scores performance was compared to that of the previous severity scores. Results New scoring system for 28-day mortality was based on six variables (score range, 0–8): vital signs at ED presentation (respiratory rate, body temperature, and altered mentation), lung cancer type, and two laboratory values (lactate and albumin) in septic shock (VitaL CLASS). The C-statistic of the VitaL CLASS score was 0.808 in the development set and 0.736 in the validation set, that is superior to that of the Sequential Organ Failure Assessment score (0.656, p = 0.01) and similar to that of the Acute Physiology and Chronic Health Evaluation II score (0.682, p = 0.08). This score could identify 41% of patients with a low-risk group (observed 28-day mortality, 10.3%) and 7% of patients with a high-risk group (observed 28-day mortality, 73.3%). Conclusions The VitaL CLASS score could be used for both risk stratification and as part of a shared clinical decision-making strategy for stage IV solid cancer patients with septic shock admitting at ED within several hours

    Preparation of low-radioactive high-purity enriched 100MoO3 powder for AMoRE-II experiment

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    This paper describes preparing radiopure molybdenum trioxide powder enriched with Mo-100 isotope for the AMoRE-II experiment. AMoRE-II, the second phase of the AMoRE experiments, will search for the neutrinoless double-beta decay (0νDBD) of the 100Mo isotope using over 100 kg of 100Mo embedded in 200 kg of ultra-pure Li2100MoO4 bolometric crystals. Efficient purification technology was developed and adapted to purify 100MoO3 powder with a 5 kg per month production capacity. Based on the ICP-MS analysis of purified powder, the 232Th and 238U were reduced to &lt;9.4 μBq/kg and &lt;50 μBq/kg, respectively. The concentrations of potassium, transition metals, and heavy metals were lower than 1 ppm. HPGe counting confirmed the reduction of progenies from the 232Th and 238U decay chains, reporting upper limits of &lt;27 μBq/kg for 228Ac and &lt;16 μBq/kg for 228Th. The 226Ra activity was acceptable at 110 ± 30 μBq/kg. In the last 3 years, 100 kg of pure 100MoO3 powder was produced. The production yield for the final purified product was above 90%, while irrecoverable losses were under 1.5%, and all by-products could be recycled further

    Korean Shock Society septic shock registry: a preliminary report

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    Objective To evaluate the clinical characteristics, therapeutic interventions, and outcomes of patients with septic shock admitted to the emergency department (ED). Methods This study was a preliminary, descriptive analysis of a prospective, multi-center, observational registry of the EDs of 10 hospitals participating in the Korean Shock Society. Patients aged 19 years or older who had a suspected or confirmed infection and evidence of refractory hypotension or hypoperfusion were included. Results A total of 468 patients were enrolled (median age, 71.3 years; male, 55.1%; refractory hypotension, 82.9%; hyperlactatemia without hypotension, 17.1%). Respiratory infection was the most common source of infection (31.0%). The median Sepsis-related Organ Failure Assessment score was 7.5. The sepsis bundle compliance was 91.2% for lactate measurement, 70.3% for blood culture, 68.4% for antibiotic administration, 80.3% for fluid resuscitation, 97.8% for vasopressor application, 68.0% for central venous pressure measurement, 22.0% for central venous oxygen saturation measurement, and 59.2% for repeated lactate measurement. Among patients who underwent interventions for source control (n=117, 25.1%), 43 (36.8%) received interventions within 12 hours of ED arrival. The in-hospital, 28-day, and 90-day mortality rates were 22.9%, 21.8%, and 27.1%, respectively. The median ED and hospital lengths of stay were 6.8 hours and 12 days, respectively. Conclusion This preliminary report revealed a mortality of over 20% in patients with septic shock, which suggests that there are areas for improvement in terms of the quality of initial resuscitation and outcomes of septic shock patients in the ED

    Risk of Peptic Ulcer Bleeding Associated with Infection, Nonsteroidal Anti-inflammatory Drugs, and Low-dose Aspirin Therapy in Peptic Ulcer Disease: A Case-control Study

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    Background/Aims The association between Helicobacter pylori infection and nonsteroidal anti-inflammatory drugs (NSAIDs) or low-dose aspirin therapy as a risk factor for peptic ulcer bleeding (PUB) remains unclear. This study investigated the risk of PUB associated with H. pylori infection and NSAID or low-dose aspirin therapy in patients with PUD. Materials and Methods This case-control study investigated 340 patients with PUB between 2012 and 2016. The control group comprised age and sex-matched patients with endoscopically documented non-bleeding ulcers. Using logistic regression analysis, the adjusted odds ratio (AOR) was calculated for the risk of PUB. Results Of the patients investigated, 57.9% in the study group and Results Of the patients investigated, 57.9% in the study group and 51.8% in the control group were diagnosed with H. pylori infection (P=0.106). Logistic regression analysis showed synergistic interaction between H. pylori infection and low-dose aspirin therapy. Multivariate analysis showed that low-dose aspirin (AOR 3.92, P=0.001), NSAIDs (AOR 2.98, P=0.001), warfarin (AOR 14.57, P=0.011), gastric ulcer (compared with duodenal ulcer) (AOR 1.65, P=0.01), and smoking (AOR 1.97, P=0.004) increased the risk of PUB compared with the risk of PUD.Conclusions: Both NSAIDs and aspirin are independent risk factors for bleeding in patients with PUD. Additionally, low-dose aspirin therapy concomitant with H. pylori infection produced a synergistic effect. Therefore, H. pylori eradication may be crucial in aspirin users. Moreover, a proton pump inhibitor should be prescribed in patients with a history of bleeding ulcers who need long-term NSAID treatment
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