• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.1
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• pp.23-32
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• 2022

Pyroprocessing is a promising technology for managing spent nuclear fuel. The nuclear material accounting of feed material is a challenging issue in safeguarding pyroprocessing facilities. The input material in pyroprocessing is in a solid-state, unlike the solution state in an input accountability tank used in conventional wet-type reprocessing. To reduce the uncertainty of the input material accounting, a double-stage homogenization process is proposed in considering the process throughput, remote controllability, and remote maintenance of an engineering-scale pyroprocessing facility. This study tests two types of mixing equipment in the proposed double-stage homogenization process using surrogate materials. The expected heterogeneity and accounting uncertainty of Pu are calculated based on the surrogate test results. The heterogeneity of Pu was 0.584% obtained from Pressurized Water Reactor (PWR) spent fuel of 59 WGd/tU when the relative standard deviation of the mass ratio, tested from the surrogate powder, is 1%. The uncertainty of the Pu accounting can be lower than 1% when the uncertainty of the spent fuel mass charged into the first mixers is 2%, and the uncertainty of the first sampling mass is 5%.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.749-755
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• 2023

A new approximation method was proposed for treating the non-resonant spatial self-shielding effects of double heterogeneous region such as the double heterogeneous effect of VHTR fuel compact in the thermal energy range and that of BP compact with BISO. The method was developed based on the effective homogenization method and a spherical unit cell model with explicit coated layers and a matrix layer. The self-shielding factor was derived from the relation between the collision probabilities for a double heterogeneous compact and the effective cross section for the homogenized compact. First, the collision probabilities and transmission probabilities for all layers of the spherical model were calculated using conventional collision probability solver. Then, the effective cross section for the homogenized sphere cell representing the homogenized compact was obtained from the transmission probability calculated using the probability density function of a chord length. The verification calculations revealed that the proposed method can predict the self-shielding factor with a maximum error of 2.3% and the double heterogeneous effect with a maximum error of 200 pcm in the typical VHTR problems with various packing fractions and BP compact sizes.

• Nuclear Engineering and Technology
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• v.52 no.3
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• pp.461-468
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• 2020

The improvements of the DeCART/MUSAD code system for uncertainty analysis of HTGR neutronic parameters are presented in this paper. The function for quantifying an uncertainty of critical-spectrumweighted few group cross section was implemented using the generalized adjoint B₁ equation solver. Though the changes between the infinite and critical spectra cause a considerable difference in the contribution by the graphite scattering cross section, it does not significantly affect the total uncertainty. To reduce the number of iterations of the generalized adjoint transport equation solver, the generalized adjoint B₁ solution was used as the initial value for it and the number of iterations decreased to 50%. To reflect the implicit uncertainty, the correction factor was derived with the resonance integral. Moreover, an additional correction factor for the double heterogeneity was derived with the effective cross section of the DH region and it reduces the difference from the complete uncertainty. The code system was examined with the MHTGR-350 Ex.II-2 3D core benchmark. The k_eff uncertainty for Ex.II-2a with only the fresh fuel block was similar to that of the block and the uncertainty for Ex.II-2b with the fresh fuel and the burnt fuel blocks was smaller than that of the fresh fuel block.

• Tunnel and Underground Space
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• v.13 no.6
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• pp.444-454
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• 2003

Rock fragmentation technique by cutter penetration has widely been used in the mechanical tunnel excavation. Microcracks propagate and interact because of locally concentrated high stress induced by cutter penetration. which is caused by heterogeneity of rocks. In this study Weibull distribution function and degradation index are used to consider the strength heterogeneity of a rock and the degradation of rock properties after failure. Through the numerical analyses, it is shown that the lateral pressure has an important influence on the rock fragmentation. In the single cutter penetration, large chips are formed as lateral pressure increase. The cutter spacing is also an important factor that affects the rock fragmentation in the double cutter penetration. The fragmentation efficiency of the double cutter penetration is better when cutter spacing is 70 mm than 40 mm and 100 mm. From the results, it is expected that this study can be applied to a TBM tunnel design by understanding of chipping process and mechanism of rock due to cutter penetration.

• Atmosphere
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• v.26 no.3
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• pp.473-482
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• 2016

An accurate determination of turbulent fluxes over an urban area is a challenging task due to its morphological diversity and associated flow complexity. In this study, an eddy covariance (EC) method is applied over a highly heterogeneous urban area in a small city (Gongju), South Korea to investigate the quantitative influence of 'coordinate tilt' in determining the turbulent fluxes of sensible heat, latent heat, momentum, and carbon dioxide mass. Two widely-used coordinate transform methods are adopted and applied to eight directional sections centered on the site to analyze a 1-year period EC measurement obtained from the urban site: double rotation (DR) and planar fit (PF) transform. The results show that mean streamline planes determined by the PF method are distinguished from the sections, representing morphological heterogeneity of the site. The sectional pitch angles determined by the DR method also compare well with those in the PF method. Both the PF and DR methods show large variabilities in the determined streamline planes at each directional section, implying that flow patterns may form in a complicate way due to the surface heterogeneity. Resulting relative differences of the turbulent fluxes, defined by $(F_{DR}-F_{PF})/F_{DR}$, are found on average +13% in sensible heat flux, +21% in latent heat flux, +37% in momentum flux, and +26% in carbon dioxide mass flux, which are larger values than those reported previously for fairly homogeneous natural sites. The fractional differences depend significantly on wind direction, showing larger differences in northerly winds at the measurement site. It is also found that the relative fractional differences are negatively correlated with the mean wind speed at both stable/unstable atmospheric conditions. These results imply that EC turbulent fluxes determined over heterogeneous urban areas should be carefully interpreted with considering the uncertainty due to 'coordinate tilt' effect in their applications.

• BMB Reports
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• v.56 no.5
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• pp.302-307
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• 2023

Lyn, a tyrosine kinase that is activated by double-stranded DNA-damaging agents, is involved in various signaling pathways, such as proliferation, apoptosis, and DNA repair. Ribosomal protein S3 (RpS3) is involved in protein biosynthesis as a component of the ribosome complex and possesses endonuclease activity to repair damaged DNA. Herein, we demonstrated that rpS3 and Lyn interact with each other, and the phosphorylation of rpS3 by Lyn, causing ribosome heterogeneity, upregulates the translation of p-glycoprotein, which is a gene product of multidrug resistance gene 1. In addition, we found that two different regions of the rpS3 protein are associated with the SH1 and SH3 domains of Lyn. An in vitro immunocomplex kinase assay indicated that the rpS3 protein acts as a substrate for Lyn, which phosphorylates the Y167 residue of rpS3. Furthermore, by adding various kinase inhibitors, we confirmed that the phosphorylation status of rpS3 was regulated by both Lyn and doxorubicin, and the phosphorylation of rpS3 by Lyn increased drug resistance in cells by upregulating p-glycoprotein translation.

• Clinical and Experimental Pediatrics
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• v.49 no.2
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• pp.136-143
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• 2006

The relationship between H. pylori(Hp) infection and recurrent abdominal pain(RAP) in children is not clear. Current data in the literature regarding a causal relationship between Hp infection and childhood RAP are conflicting. However, meta-analysis and most of the recently published studies have not supported an association between Hp infection and an increased prevalence of abdominal pain. Most published studies have some problems and have been criticized on methodological grounds. Most of the existing studies have not been designed to include double-blind placebo controls. And, because of the low incidence of Hp infection in children, they have a problem of obtaining sufficient numbers of the Hp infected children. There is also a concern about the heterogeneity of testing methodology in the studies and diagnostic accuracy problems of the non-invasive tests such as low sensitivity of the serology tests and false positive results of the UBT in children. And conflicting results may be explained, in part, by the poor definition of RAP or dyspepsia for the study subjects. To date, no consensus exists for the treatment of Hp-infected children with RAP. Some authors suggest the clinical efficacy of Hp. But others suggest that eradication of Hp is not associated with improvement of RAP. The problem of the most treatment studies is that they had usually no control groups and the number of the subjects was small. In order to make reasonable decisions about treatment of Hp infection in children with RAP, long-term, randomized, double blind, well controlled studies in large numbers of children will be required.

• Journal of Music and Human Behavior
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• v.10 no.2
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• pp.1-33
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• 2013

The aim of this study was to systematically review the latest clinical trials in music medicine and medical music therapy for pediatric patients. Thirteen databases were searched to obtain randomized controlled/crossover design studies published between the year 2000 and 2012 in English language. Out of 1012 articles retrieved in the initial search, fifteen studies were identified based on an exclusion criteria. Overall, selected articles involved children 1 month to 18 years, sample size of 11 to 150, and total participants of 987. Studies were classified and compared as music medicine or music therapy studies through a systematic synthesis assessing general characteristics, methodological quality, measured outcomes, types of interventions and the study results. Seven music medicine and eight music therapy studies measured seven dependent variables using thirty-six different measurement tools with a large heterogeneity in the selection, type, and method of music interventions. Evaluation of the methodological quality revealed that many studies did not provide a full report of the research method, and did not meet some or most methodological standards, such as randomization, allocation concealment, double or partial blinding, and intention to treat analysis. Although overall research results were positive if not significant, poor methodological quality and heterogeneity in design and intervention strategies raise the question of research bias and trustworthiness issues. The systematic review concluded that music may have a valuable clinical effect in addressing the physical and psychosocial needs of hospitalized children, although more rigorous, homogeneous and replicable studies are greatly needed.

• Journal of Veterinary Science
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• v.23 no.1
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• pp.13.1-13.12
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• 2022

Background: Toxoplasma gondii can infect humans and most animals and has a very high infection rate worldwide, including in China. The number of people infected with T. gondii in China increases with the number of cats. Objectives: We investigated the seropositive rate of T. gondii in cats over the last five years and analyzed the risk factors via meta-analysis. Methods: We retrieved 20 studies, with a total of 5,158 cats, published between 2016 and 2020, used the DerSimonian-Laird model and calculated seroprevalence estimates with the variance stabilizing double arcsine transformation. Results: The overall seroprevalence rate after sinusoidal conversion was 19.9% (95% confidence interval [CI], 15.9-23.9; 966/5,158), lower than the domestic report from 1995 to 2015 (24.5%, 95% CI, 20.1-29.0). There was substantial heterogeneity among studies (χ² = 262.32; p < 0.001; I² = 64.6%). Regression analysis of possible heterogeneous causes and subgroup analysis showed that age and whether cats were stray or not have a significant effect on the seropositive rate. Conclusions: Articles published in recent five years suggest that the seroprevalence estimates of Toxoplasma gondii in cats has decreased. Cats, as the final host of T. gondii, are an important cause of the spread of the parasite, and this is an important concern for public health.

• Journal of Dental Anesthesia and Pain Medicine
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• v.21 no.5
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• pp.413-429
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• 2021

Background: Migraine headaches are the second leading cause of disability worldwide and are responsible for significant morbidity, reduction in the quality of life, and loss of productivity on a global scale. The purpose of this systematic review and meta-analysis was to evaluate the efficacy of ketamine on migraines and other primary headache disorders compared to placebo and other active interventions, such as midazolam, metoclopramide/diphenhydramine, and prochlorperazine/diphenhydramine. Methods: An electronic search of databases published up to February 2021, including Medline via PubMed, EMBASE, Web of Science, and Cochrane Library, a hand search of the bibliographies of the included studies, as well as literature and systematic reviews found through the search was conducted to identify randomized controlled trials (RCTs) investigating ketamine in the treatment of migraine/headache disorders compared to the placebo. The authors assessed the risk of bias according to the Cochrane Handbook guidelines. Results: The initial search strategy yielded 398 unduplicated references, which were independently assessed by three review authors. After evaluation, this number was reduced to five RCTs (two unclear risk of bias and three high risk of bias). The total number of patients in all the studies was 193. Due to the high risk of bias, small sample size, heterogeneity of the outcomes reported, and heterogeneity of the comparison groups, the quality of the evidence was very low. One RCT reported that intranasal ketamine was superior to intranasal midazolam in improving the aura attack severity, but not duration, while another reported that intranasal ketamine was not superior to metoclopramide and diphenhydramine in reducing the headache severity. In one trial, subcutaneous ketamine was superior to saline in migraine severity reduction; however, intravenous (I.V.) ketamine was inferior to I.V. prochlorperazine and diphenhydramine in another study. Conclusion: Further double-blind controlled studies are needed to assess the efficacy of ketamine in treating acute and chronic refractory migraines and other primary headaches using intranasal and subcutaneous routes. These studies should include a long-term follow-up and different ketamine dosages in diagnosed patients following international standards for diagnosing headache/migraine.