Biological dosimetry dose-response curves for residents living near nuclear power plants in South Korea.

The purpose of this study was to establish the dose-response curves for biological dosimetry of the Dong Nam Institute of Radiological and Medical Sciences to monitor radiation exposure of local residents in the vicinity of the nuclear power plant. The blood samples of five healthy volunteers were irradiated with gamma ray, and each sample was divided equally for analysis of chromosomal aberrations by Giemsa staining and three-color fluorescence in situ hybridization painting of the triplet (chromosomes #1, #2, and #4). The results of chromosomal aberrations followed the Poisson distribution in all individual and averaged data which include inter-individual variation in radiation susceptibility. Cytogenetics Dose Estimate Software version 5.2 was used to fit the dose-response curve and to determine the coefficients of linear-quadratic equations. The goodness of fit of the curves and statistical significance of fitted α and ß-coefficients were confirmed in both Giemsa-based dicentric analysis and FISH-based translocation analysis. The coefficients calculated from the five-donor average data were almost identical in both of the analyses. We also present the results that the dose-response curve for dicentric chromosomes plus fragments could be more effective for dose estimation following low-dose radiation accidents.

Dicentric chromosome assay using a deep learning-based automated system.

The dicentric chromosome assay is the "gold standard" in biodosimetry for estimating radiation exposure. However, its large-scale deployment is limited owing to its time-consuming nature and requirement for expert reviewers. Therefore, a recently developed automated system was evaluated for the dicentric chromosome assay. A previously constructed deep learning-based automatic dose-estimation system (DLADES) was used to construct dose curves and calculate estimated doses. Blood samples from two donors were exposed to cobalt-60 gamma rays (0-4 Gy, 0.8 Gy/min). The DLADES efficiently identified monocentric and dicentric chromosomes but showed impaired recognition of complete cells with 46 chromosomes. We estimated the chromosome number of each "Accepted" sample in the DLADES and sorted similar-quality images by removing outliers using the 1.5IQR method. Eleven of the 12 data points followed Poisson distribution. Blind samples were prepared for each dose to verify the accuracy of the estimated dose generated by the curve. The estimated dose was calculated using Merkle's method. The actual dose for each sample was within the 95% confidence limits of the estimated dose. Sorting similar-quality images using chromosome numbers is crucial for the automated dicentric chromosome assay. We successfully constructed a dose-response curve and determined the estimated dose using the DLADES.

Unravelling the Nature of the Intrinsic Complex Structure of Binary-Phase Na-Layered Oxides.

The layered sodium transition metal oxide, NaTMO2 (TM = transition metal), with a binary or ternary phases has displayed outstanding electrochemical performance as a new class of strategy cathode materials for sodium-ion batteries (SIBs). Herein, an in-depth phase analysis of developed Na1-x TMO2 cathode materials, Na0.76 Ni0.20 Fe0.40 Mn0.40 O2 with P2- and O3-type phases (NFMO-P2/O3) is offered. Structural visualization on an atomic scale is also provided and the following findings are unveiled: i) the existence of a mixed-phase intergrowth layer distribution and unequal distribution of P2 and O3 phases along two different crystal plane indices and ii) a complete reversible charge/discharge process for the initial two cycles that displays a simple phase transformation, which is unprecedented. Moreover, first-principles calculations support the evidence of the formation of a binary NFMO-P2/O3 compound, over the proposed hypothetical monophasic structures (O3, P3, O'3, and P2 phases). As a result, the synergetic effect of the simultaneous existence of P- and O-type phases with their unique structures allows an extraordinary level of capacity retention in a wide range of voltage (1.5-4.5 V). It is believed that the insightful understanding of the proposed materials can introduce new perspectives for the development of high-voltage cathode materials for SIBs.

Protective effect of fermented aloe extract on glutamate-induced cytotoxicity in HT22 cells.

Excessive glutamate can cause oxidative stress in neuronal cells and this can significantly contribute to the etiology of neurodegenerative disease. The present study mainly aims to investigate that aloe extract (AE) and fermented aloe extract (FAE) could protect against glutamate-induced cytotoxicity by modulating oxidative stress. In this study, both AE and FAE showed potent neuroprotective activity by inhibiting ROS and Ca2+ concentration, increasing mitochondria membrane potential, and activating glutathione-related enzymes against glutamate-insulted neurotoxicity in HT22 cells. In addition, the neuroprotective activity of FAE was more potent than that of AE. HPLC analysis reveals that the chemical composition of FAE is different from that of AE. Especially, the contents of aloin A, aloin B and aloenin were higher in FAE than in AE. In conclusion, this study indicates that both AE and FAE may have effective neuroprotective activity in glutamate-insulted pathological conditions such as Alzheimer's disease by managing oxidative stress.

Minimising oxygen contamination through a liquid copper-aided group IV metal production process.

This paper demonstrates for the first time the fabrication of Zr-Cu alloy ingots from a Hf- free ZrO2 precursor in a molten CaCl2 medium to recover nuclear-grade Zr. The reduction of ZrO2 in the presence of CaO was accelerated by the formation of Ca metal in the intermediate stage of the process. Tests conducted with various amounts of ZrO2 indicate that the ZrO2 was reduced to the metallic form at low potentials applied at the cathode, and the main part of the zirconium was converted to a CuZr alloy with a different composition. The maximum oxygen content values in the CuZr alloy and Zr samples upon using liquid Cu were less than 300 and 891 ppm, respectively. However, Al contamination was observed in the CuZr during the electroreduction process. In order to solve the Al contamination problem, the fabrication process of CuZr was performed using the metallothermic reduction process, and the produced CuZr was used for electrorefining. The CuZr alloy was further purified by a molten salt electrorefining process to recover pure nuclear-grade Zr in a LiF-Ba2ZrF8-based molten salt, the latter of which was fabricated from a waste pickling acid of a Zr clad tube. After the electrorefining process, the recovered Zr metal was fabricated into nuclear-grade Zr buttons through arc melting following a salt distillation process. The results suggest that the removal of oxygen from the reduction product is a key reason for the use of a liquid CaCu reduction agent.

Discrimination of the cultivar, growing region, and geographical origin of rice (Oryza sativa) using a mass spectrometer-based electronic nose.

The objective of this study was to discrimination the cultivar, growing region, and geographical origin of rice (Oryza sativa) using a mass spectrometry-based electronic nose (MSE-nose). The inside-needle dynamic extraction (INDEX) system was used to concentrate the samples for MSEnose, following which the ion fragment data obtained were used to perform discriminant function analysis. Discriminant functions 1 and 2 readily separated all 16 cultivars of rice sampled. It was also confirmed that MSE-nose could distinguish the region in which rice cv. Chucheong and Koshihikari were grown, likely due to variation in environmental factors, such as soil and climate. Finally, it was confirmed that MSE-nose could be used to detect the geographical origin of rice, discrimination Korea rice from Japanese rice. Therefore, this simple and rapid technique is of value for discriminating the cultivar, growing region, and geographical origin of rice.

Screening DNA chip and event-specific multiplex PCR detection methods for biotech crops.

BACKGROUND: There are about 80 biotech crop events that have been approved by safety assessment in Korea. They have been controlled by genetically modified organism (GMO) and living modified organism (LMO) labeling systems. The DNA-based detection method has been used as an efficient scientific management tool. Recently, the multiplex polymerase chain reaction (PCR) and DNA chip have been developed as simultaneous detection methods for several biotech crops' events. RESULTS: The event-specific multiplex PCR method was developed to detect five biotech maize events: MIR604, Event 3272, LY 038, MON 88017 and DAS-59122-7. The specificity was confirmed and the sensitivity was 0.5%. The screening DNA chip was developed from four endogenous genes of soybean, maize, cotton and canola respectively along with two regulatory elements and seven genes: P35S, tNOS, pat, bar, epsps1, epsps2, pmi, cry1Ac and cry3B. The specificity was confirmed and the sensitivity was 0.5% for four crops' 12 events: one soybean, six maize, three cotton and two canola events. CONCLUSION: The multiplex PCR and DNA chip can be available for screening, gene-specific and event-specific analysis of biotech crops as efficient detection methods by saving on workload and time. © 2014 Society of Chemical Industry.

Simplex and duplex event-specific analytical methods for functional biotech maize.

Analytical methods are very important in the control of genetically modified organism (GMO) labeling systems or living modified organism (LMO) management for biotech crops. Event-specific primers and probes were developed for qualitative and quantitative analysis for biotech maize event 3272 and LY 038 on the basis of the 3' flanking regions, respectively. The qualitative primers confirmed the specificity by a single PCR product and sensitivity to 0.05% as a limit of detection (LOD). Simplex and duplex quantitative methods were also developed using TaqMan real-time PCR. One synthetic plasmid was constructed from two taxon-specific DNA sequences of maize and two event-specific 3' flanking DNA sequences of event 3272 and LY 038 as reference molecules. In-house validation of the quantitative methods was performed using six levels of mixing samples, from 0.1 to 10.0%. As a result, the biases from the true value and the relative deviations were all within the range of +/-30%. Limits of quantitation (LOQs) of the quantitative methods were all 0.1% for simplex real-time PCRs of event 3272 and LY 038 and 0.5% for duplex real-time PCR of LY 038. This study reports that event-specific analytical methods were applicable for qualitative and quantitative analysis for biotech maize event 3272 and LY 038.

Detection methods for biotech cotton MON 15985 and MON 88913 by PCR.

Plants derived through agricultural biotechnology, or genetically modified organisms (GMOs), may affect human health and ecological environment. A living GMO is also called a living modified organism (LMO). Biotech cotton is a GMO in food or feed and also an LMO in the environment. Recently, two varieties of biotech cotton, MON 15985 and MON 88913, were developed by Monsanto Co. The detection method is an essential element for the GMO labeling system or LMO management of biotech plants. In this paper, two primer pairs and probes were designed for specific amplification of 116 and 120 bp PCR products from MON 15985 and MON 88913, respectively, with no amplification from any other biotech cotton. Limits of detection of the qualitative method were all 0.05% for MON 15985 and MON 88913. The quantitative method was developed using a TaqMan real-time PCR. A synthetic plasmid, as a reference molecule, was constructed from a taxon-specific DNA sequence of cotton and two construct-specific DNA sequences of MON 15985 and MON 88913. The quantitative method was validated using six samples that contained levels of biotech cotton mixed with conventional cotton ranging from 0.1 to 10.0%. As a result, the biases from the true value and the relative deviations were all within the range of +/-20%. Limits of quantitation of the quantitative method were all 0.1%. Consequently, it is reported that the proposed detection methods were applicable for qualitative and quantitative analyses for biotech cotton MON 15985 and MON 88913.

[A case of rectal schwannoma presenting with hematochezia].

Rectal schwannoma is a rare mesenchymal tumor originating from Schwann's cell. We experienced a 61- year-old female patient who complained of blood tinged and narrow calibered stool for several years, and found a 4 cm sized submucosal tumor with a central ulcer on the rectal wall during colonoscopy. She underwent transanal excision. Microscopically, the tumor was composed of fasciculating bundles of spindle cells with benign nuclear atypia and peripheral lymphoid cell cuffing. Tumor cells showed a diffuse strong immunoreactivity to S-100 protein, but not stain for CD 34, desmin and smooth muscle actin. This is the first case report of rectal schwannoma in Korea.

Qualitative and quantitative polymerase chain reaction analysis for genetically modified maize MON863.

Qualitative and quantitative analytical methods were developed for the new event of genetically modified (GM) maize, MON863. One specific primer pair was designed for the qualitative polymerase chain reaction (PCR) method. The specificity and sensitivity of the designed primers were confirmed. PCR was performed on genomic DNAs extracted from MON863, other GM events, and cereal crops. Single PCR product was obtained from MON863 by the designed primer pair. Eight test samples including GM maize MON863 were prepared at 0.01 approximately 10% levels and analyzed by PCR. Limit of detection of the method was 0.01% for GM maize MON863. On the other hand, another specific primer pair and probe were also designed for quantitative method using a real-time polymerase chain reaction. As a reference molecule, a plasmid was constructed from a taxon-specific DNA sequence for maize, a universal sequence for a cauliflower mosaic virus (CaMV) 35S promoter used in most genetically modified organisms, and a construct-specific DNA sequence for the MON863 event. Six test samples of 0.1, 0.5, 1.0, 3.0, 5.0 and 10.0% of GM maize MON863 were quantitated for the validation of this method. At the 3.0% level, the bias (mean vs true value) for MON863 was 3.0%, and its relative standard deviation was 5.5%. Limit of quantitation of the method was 0.5%. These results show that the developed PCR methods can be used to qualitatively and quantitatively detect GM maize MON863.

Clinicopathologic significance of gastric and intestinal phenotypic marker expression in gastric carcinomas.

BACKGROUND: It is well known that both gastric and intestinal phenotypic cell markers are expressed in gastric cancers. This study was aimed at investigating the correlation between gastric and intestinal phenotypic marker expression patterns of tumors and the clinicopathologic characteristics of gastric carcinomas. METHODS: We evaluated phenotypic marker expression by immunohistochemical staining with monoclonal antibodies. All tumors were classified as gastric (G), gastric and intestinal mixed (GI), intestinal (I), or null (N) phenotype. RESULTS: The tumors were phenotypically divided into G-phenotype tumors (33.2%), GI-phenotype tumors (25.7%), I-phenotype tumors (26.8%), and N-phenotype tumors (14.3%). N-phenotype tumors were associated with more corporeal location than GI- and I-phenotype tumors (o=0.009 and p=0.007, respectively), a larger size than I-phenotype tumors (0=0.007), a higher proportion of advanced gastric cancers than G-, GI-, and I-phenotype tumors (0=0.003, p<0.001, and p<0.001, respectively), more perineural invasion than G-, GI-, and I-phenotype tumors (p=0.076, p=0.003, and p=0.003, respectively), and more lymph node metastasis than GI-phenotype tumors (p=0.017). I-phenotype tumors were associated with a higher proportion of intestinal-type tumors than G-, GI-, and N-phenotype tumors (p<0.001, p=0.011, and p<0.001, respectively). CONCLUSION: Our results indicate that the gastric and intestinal phenotypic marker expression pattern of tumors is prognostically useful for patients with gastric carcinoma.