Assuming a standard Maxwellian for the WIMP velocity distribution, we obtain the bounds from null WIMP search results of 59.5 days of COSINE-100 data on the DAMA/LIBRA-phase2 modulation effect within ...the context of the non-relativistic effective theory of WIMP-nucleus scattering. Here, we systematically assume that one of the effective operators allowed by Galilean invariance dominates in the effective Hamiltonian of a spin-1/2 dark matter (DM) particle. We find that, although DAMA/LIBRA and COSINE-100 use the same sodium-iodide target, the comparison of the two results still depends on the particle-physics model. This is mainly due to two reasons: i) the WIMP signal spectral shape; ii) the expected modulation fractions, when the upper bound on the time-averaged rate in COSINE-100 is converted into a constraint on the annual modulation component in DAMA/LIBRA . We find that the latter effect is the dominant one. For several effective operators the expected modulation fractions are larger than in the standard spin-independent or spin-dependent interaction cases. As a consequence, compatibility between the modulation effect observed in DAMA/LIBRA and the null result from COSINE-100 is still possible for several non-relativistic operators. At low WIMP masses such relatively high values of the modulation fractions arise because COSINE-100 is mainly sensitive to WIMP-sodium scattering events, due to the higher threshold compared to DAMA/LIBRA . A next COSINE analysis is expected to have a full sensitivity for the 5 σ region of DAMA/LIBRA.
Purpose The aim of the present study was to correlate the staging of bisphosphonate-related osteonecrosis of the jaws (BRONJ) with serum C-terminal cross-linking telopeptide of type I collagen (CTX), ...which is under debate as an index of risk prediction. Stage I BRONJ was defined as asymptomatic osteonecrotic bone. Stage II BRONJ includes infection, and stage III includes additional complications such as fracture or extraoral fistulas. Patients and Methods The serum CTX values of 18 patients (mean age 74 years) who were diagnosed with osteonecrosis of the jaws caused by oral bisphosphonate were investigated. Results The serum CTX values ranged from 10 to 262 pg/mL (mean 112 ± 76.1). The mean duration of bisphosphonate therapy was 3.9 years, and 17 of the 18 patients had received once weekly 70 mg aldendronate and 1 patient once weekly 35 mg risedronate. The risk assessment was rated according to the CTX values of the individual patient (minimal risk, more than 150 pg/mL; moderate, 100 to 150 pg/mL; and high, less than 100 pg/mL). Next, the BRONJ scores were calculated according to the number of the BRONJ lesions and their stage. The risk assessment and BRONJ scores were correlated. The result was statistically significant ( P = .019). Conclusions BRONJ is relatively rare but has been increasingly recognized in our clinic. The usefulness of the serum CTX value as an index of risk prediction continues to be debated. Considering the staging of lesions and the number of lesions, we found a significant correlation between the disease severity and the risk assessment using serum CTX.
The fast neutron rates are compared at the site of the NEOS (Neutrino Experiment Oscillation Short baseline) experiment, a short-baseline neutrino experiment located in a tendon gallery of a ...commercial nuclear power plant using a 0.78-liter liquid scintillator detector. A pulse shape discrimination technique is used to identify neutron signals. The measurements are performed during the nuclear reactor-on and -off periods, and the fast neutron rates are found to be consistent with each other. The fast neutron rate is also measured at an overground site with a negligible overburden and is found to be ~ 100 times higher than that at the site of the NEOS experiment.
Construction and properties of acrylic vessels in the RENO detector Park, K.S.; Park, J.S.; Kim, B.C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2012, Letnik:
686
Journal Article
Recenzirano
The aim of the RENO (Reactor Experiment for Neutrino Oscillation) is to measure the smallest neutrino mixing angle, θ13. The RENO detector consists of four concentric cylindrical layers: the target, ...γ-catcher, buffer and veto. Acrylic is used for the target and γ-catcher vessels, both of which contain liquid scintillator. Acrylic was chosen because it has good transmittance in the wavelength range of 400–430nm and also does not react with liquid-scintillating solvents. In order to reduce systematic uncertainties, the target volume should be identical to a level of less than 0.1% between the near and far detectors. Furthermore, the acrylic vessel should not have any leaks. In this paper, we investigate the optical properties, design and construction of the acrylic vessels used in the RENO detector.
Scintillation crystals are commonly used for direct detection of weakly interacting massive particles (WIMPs), which are suitable candidates for a particle dark matter. It is well known that the ...scintillation light yields are different for electron recoil and nuclear recoil. To calibrate the energies of WIMP-induced nuclear recoil signals, the quenching factor (QF) needs to be measured, which is the light yield ratio of the nuclear recoil to electron recoil. Measurements of the QFs for Na and I recoils in a small (2 cm × 2 cm × 1.5 cm) NaI(Tl) crystal are performed with 2.43-MeV mono-energetic neutrons generated by deuteron-deuteron fusion. Depending on the scattering angle of the neutrons, the energies of the recoiled ions vary in the range of 9–152 keV for Na and 19–75 keV for I. The QFs of Na are measured at 9 points with values in the range of 10–23% while those of I are measured at 4 points with values in the range of 4–6%.
Gastric
adenocarcinoma is one of the most common malignancies in the world, and
yet little is known about its molecular process of development and
progression. Recent studies have suggested that ...ingestion of nonsteroid
anti-inflammatory drugs reduces the risk of colon cancer, presumably by
inhibiting the cyclooxygenase (COX) enzyme. COX-2, one isoform of the
COX enzyme, is the rate-limiting enzyme in prostaglandin synthesis, and
the function of this enzyme is thought to relate to inflammatory
processes and carcinogenesis. To understand the role of COX enzyme in
gastric cancer, we measured COX-2 expression in 104 human gastric
carcinoma tissues by immunohistochemical analysis. We obtained tissue
specimens from 104 surgically resected gastric adenocarcinoma patients.
We performed immunohistochemical stain for human COX-2 with polyclonal
antibody in gastric carcinoma. After curative resection and extensive
lymph node dissection, all patients received adjuvant chemotherapy
containing 5-fluorouracil. Expression of COX-2 showed cytoplasmic
staining, not only in cancer cells but also in precancerous lesions
such as metaplastic and adenomatous cells. We confirmed up-regulation
of COX-2 in gastric cancer tissues compared with normal paired mucosa
using Western blot analysis. There was no correlation between
clinicopathological characteristics of gastric cancer patients and
intensity of COX-2 protein expression. This study indicates that COX-2
protein overexpression may contribute to an early event of gastric
cancer development, and it further suggests that selective inhibition
of COX-2 may provide a chemopreventive effect against gastric
carcinogenesis.
We have studied channeling effects in a cesium iodide (CsI) crystal that is similar in composition to the ones being used in a search for Weakly Interacting Massive Particles (WIMPs) dark matter ...candidates, and measured its energy-dependent quenching factor, the relative scintillation yield for electron and nuclear recoils. The experimental results are reproduced with a GEANT4 simulation that includes a model of the scintillation efficiency as a function of electronic stopping power. We present the measured and simulated quenching factors and the estimated effects of channeling.
ZnO epitaxial layers with treated low-temperature (LT) ZnO buffer layers were grown by plasma-assisted molecular beam epitaxy (PA-MBE) on p-type Si (1
0
0) substrates. The LT-ZnO buffer layers were ...treated by thermal annealing in O
2 plasma with various radio frequency (RF) power ranging from 100 to 300
W before the ZnO epilayers growth. Atomic force microscopy (AFM), high-resolution X-ray diffraction (HR-XRD), and room-temperature (RT) photoluminescence (PL) were carried out to investigate their structural and optical properties. The surface roughness measured by AFM was improved from 2.71 to 0.59
nm. The full-width at half-maximum (FWHM) of the rocking curve observed for ZnO (0
0
2) XRD and photoluminescence of the ZnO epilayers was decreased from 0.24° to 0.18° and from 232 to 133
meV, respectively. The intensity of the XRD rocking curve and the PL emission peak were increased. The XRD intensity ratio of the ZnO (0
0
2) to Si substrates and PL intensity ratio of the near-band edge emissions (NBEE) to the deep-level emissions (DLE) as a function of the RF power was increased from 0.166 to 0.467 and from 2.54 to 4.01, respectively. These results imply that the structural and optical properties of ZnO epilayers were improved by the treatment process.
Asymmetric dimethylarginine (ADMA) is an inhibitor of nitric oxide synthase and a risk factor for cardiovascular events. We have developed a new derivatization method to enable baseline separation of ...the regio‐isomers, ADMA, and symmetric dimethylarginine (SDMA), within 15 min on a C18 reverse phase column. Reacting naphthalene‐2,3‐dicarboxaldehyde with ADMA and SDMA in the presence of 2‐mercaptoethanol produces corresponding 2,3‐dihydro‐benzofisoindol‐1‐ones that are more stable than previously reported ortho‐phthaldialdehyde and 2‐mercaptoethanol derivatives. LC‐MS/MS quantitation of these derivatives can be used to determine ADMA and SDMA concentrations in the plasma of patients to receive on‐pump coronary artery bypass grafting (CABG) surgery. The LOD, LOQ and lower LOQ (LLOQ) of this method were determined to be 2.6, 8.7, and 25 nM for ADMA, and 2.5, 8.3, and 25 nM for SDMA, respectively, with consumption of only 50 μL of plasma. The relative standard deviations and relative errors of the intraday and interday determinations, as measurements of reproducibility and accuracy, are all within 15%. The ADMA and SDMA concentrations in patient plasma are 298.1 ± 11.2 nM (mean ± S.E.M., n = 123) and 457.7 ± 19.8 nM (mean ± S.E.M., n = 123), respectively. Upon unblinding of our clinical trial, these predetermined values might explain patient clinical outcomes associated with on‐pump CABG surgery, as ADMA is known to inhibit nitric oxide production. Furthermore, this derivatization reaction in conjunction with LC‐MS/MS analysis may open a venue to explore alternative chemical labeling modes for LC‐MS/MS applications, such as analysis of other amino acids, metabolites, and peptides containing primary amine group(s).
For the newly isolated chemoheterotrophic bacterium
Citrobacter amalonaticus Y19, anaerobic glucose metabolism and hydrogen
(
H
2
)
production pathway were studied using batch cultivation and an
in ...silico metabolic-flux analysis. Batch cultivation was conducted under varying initial glucose concentration between 1.5 and 9.5
g/L with quantitative measurement of major metabolites to obtain accurate carbon material balance. The metabolic flux of Y19 was analyzed using a metabolic-pathway model which was constructed from 81 biochemical reactions. The linear optimization program MetaFluxNet was employed for the analysis. When the specific growth rate of cells was chosen as an objective function, the model described the batch culture characteristics of
Ci. amalonaticus Y19 reasonably well. When the specific
H
2
production rate was selected as an objective function, on the other hand, the achievable maximal
H
2
production yield (
8.7
mol
H
2
/
mol
glucose) and the metabolic pathway enabling the high
H
2
yield were identified. The pathway involved non-native NAD(P)-linked hydrogenase and
H
2
production from NAD(P)H which were supplied at a high rate from glucose degradation through the pentose phosphate pathway.
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