518 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
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
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
Intrinsically Stretchable Three Primary Light-Emitting Films Enabled By Elastomer Blend For Polymer Light-Emitting Diodes
Intrinsically stretchable light-emitting materials are crucial for skin-like wearable displays; however, their color range has been limited to green-like yellow lights owing to the restricted stretchable light-emitting materials (super yellow series materials). To develop skin-like full-color displays, three intrinsically stretchable primary light-emitting materials [red, green, and blue (RGB)] are essential. In this study, we report three highly stretchable primary light-emitting films made from a polymer blend of conventional RGB light-emitting polymers and a nonpolar elastomer. The blend films consist of multidimensional nanodomains of light-emitting polymers that are interconnected in an elastomer matrix for efficient light-emitting under strain. The RGB blend films exhibited over 1000 cd/m2 luminance with low turn-on voltage (Von) and the selectively stretched blend films on rigid substrate maintained stable light-emitting performance up to 100% strain even after 1000 multiple stretching cycles
Immunomodulatory effects of canine mesenchymal stem cells in an experimental atopic dermatitis model
Mesenchymal stem cells (MSCs) have the potential to differentiate into multi-lineage cells, suggesting their future applicability in regenerative medicine and biotechnology. The immunomodulatory properties of MSCs make them a promising replacement therapy in various fields of animal research including in canine atopic dermatitis (AD), a skin disease with 10–15% prevalence. We investigated the immunomodulatory effects of MSCs in an experimental canine AD model induced by Dermatophagoides farinae extract ointment. Canine adipose tissue-derived MSCs (cAT-MSCs) were differentiated into mesodermal cell lineages at the third passage. Alterations in immunomodulatory factors in control, AD, and MSC-treated AD groups were evaluated using flow cytometric analysis, enzyme-linked immunosorbent assay, and quantitative reverse transcription PCR. In the MSC-treated AD group, the number of eosinophils decreased, and the number of regulatory T cells (Tregs) increased compared to those in the AD group. In addition, the immunoglobulin E (IgE) and prostaglandin E2 levels were reduced in the MSC-treated AD group compared to those in the AD group. Furthermore, the filaggrin, vascular endothelial growth factor, and interleukin-5 gene expression levels were relatively higher in the MSC-treated AD group than in the AD group, however, not significantly. cAT-MSCs exerted immunomodulatory effects in an AD canine model via a rebalancing of type-1 and -2 T helper cells that correlated with increased levels of Tregs, IgE, and various cytokines
Bidirectional Association Between Parkinson’s Disease and Obstructive Sleep Apnea: A Cohort Study
STUDY OBJECTIVES: Chronic intermittent hypoxia due to obstructive sleep apnea (OSA) causes oxidative stress, which may contribute to the pathophysiology of Parkinson\u27s disease (PD). However, the bidirectional relationship between PD and OSA has not been satisfactorily established. The objective of this study was to try to estimate whether there is a bidirectional relationship between PD and OSA through a retrospective cohort study in the South Korean population.
METHODS: This study used data from the Korean National Health Information Database of the National Health Insurance Service, which contains data from 3.5 million individuals evenly distributed. In study 1, patients with OSA were matched in a 1:2 ratio with non-OSA controls. In study 2, patients with PD were matched in a 1:2 ratio with non-PD controls. A stratified Cox proportional hazards model was used to calculate hazard ratios.
RESULTS: In study 1, which included 6,396 patients with OSA and 12,792 non-OSA controls, the incidence of PD per 10,000 person-years was 11.59 in the OSA group and 8.46 in the non-OSA group. The OSA group demonstrated a 1.54-fold higher incidence of PD than the non-OSA group (95% confidence interval, 1.14-2.07;
CONCLUSIONS: This study supports a possible bidirectional relationship between PD and OSA.
CITATION: Jeon S-H, Hwang YS, Oh S-Y, et al. Bidirectional association between Parkinson\u27s disease and obstructive sleep apnea: a cohort study
Amniotic fluid embolism that took place during an emergent Cesarean section -A case report-
Amniotic fluid embolism (AFE) is a rare but fatal obstetric emergency, characterized by sudden cardiovascular collapse, dyspnea or respiratory arrest and altered mentality, disseminated intravascular coagulation (DIC). It can lead to severe maternal morbidity and mortality, but the prediction of its occurrence and treatment are very difficult. We experienced a case of AFE during emergent Cesarean section in a 40+6 weeks healthy pregnant woman, age 33. Sudden dyspnea, hypotension, signs of pulmonary edema and DIC were developed during Cesarean section, and cardiac arrest followed after these events. The course of these events was so rapid and catastrophic, which was consistent with AFE. Thus, we report this case precisely and review pathophysiology, diagnosis, treatment of AFE by referring to up-to-date literatures
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Caspase-4 is essential for saikosaponin a-induced apoptosis acting upstream of caspase-2 and γ-H2AX in colon cancer cells
Saikosaponin a (SSa), a bioactive phytochemical from Bupleurum, triggers sequential caspase-2 and caspase-8 activation, and thereby induces caspase-mediated apoptosis in human colon carcinoma (HCC) cells. However, the upstream mechanism of caspase-2 activation remains unknown. Therefore, we investigated the signaling mechanisms underlying SSa-induced caspase activation and apoptosis in HCC cells. SSa treatment triggered marked antitumor effects, especially in HCC cells, in a cell culture model and a mouse xenograft model. SSa also induced the activation of several endoplasmic reticulum (ER) stress signals. Specifically, caspase-4, a critical regulator of ER stress-induced apoptosis, was activated significantly after SSa treatment. Mechanistically, selective inhibition of caspase-4 suppressed SSa-induced apoptosis, colony inhibition, and the activation of caspase-3, -8, and -2, but not vice versa. Consistent with the important role of caspase-2 in the DNA damage response, SSa induced DNA damage, as evidenced by a cytokinesis-block micronucleus assay, single-cell gel electrophoresis, and an increase in the levels of γ-H2AX, a DNA damage marker. Moreover, inhibition of caspase-4 activation inhibited SSa-induced histone H2AX phosphorylation. Taken together, these results suggest that caspase-4 is an upstream regulator of SSa-induced DNA damage and caspase activation in HCC cells. Given that SSa-induced apoptosis appeared to be specific to certain cell types including HCC cells, SSa may be a promising cancer therapy agent in certain types of cancer
Massive Left Atrial Calcification Associated with Mitral Valve Replacement
Calcification of the left atrium can be observed in patients with a long-lasting rheumatic heart disease. However, massive calcification of the atrial wall, so called porcelain or coconut atrium is very rare and has been generally reported only as incidental radiographic findings. We report a case of massive and firm calcifications at the left atrium in patient who underwent mitral valve replacement
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