A ²³⁵U mass measurement method for UO₂ rod assembly based on the n/γ joint measurement system

Yang, Jianqing,Zhang, Quanhu,Su, Xianghua,Li, Sufen,Zhuang, Lin,Hou, Suxia,Huo, Yonggang,Zhou, Hao,Liu, Guorong Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.5

Fast-Neutron Multiplicity Counter based on Liquid Scintillator Detector can directly measure the fast neutron multiplicity emitted by UO₂ rod. HPGe gamma spectrometer; which has superior energy resolution; is routinely used for the gamma energy spectrum measurement. Combing Fast-Neutron Multiplicity Counter and HPGe γ-spectrometer, the n/γ joint measurement system is developed. The fast neutron multiplicity and gamma energy spectrum of UO₂ rod assemblies under different conditions are measured by the n/γ joint measurement system. The induced fission rate and the ²³⁵U abundance, thereby the ²³⁵U mass; can be obtained for UO₂ rod assemblies. The ²³⁵U mass deviation of the measured value from the reference value is less than 5%. The results show that the n/γ joint measurement system is effective and applicable in the measurement of the ²³⁵U mass in samples.

Efficiency calculation of the ⁿMCP with ¹⁰B doping based on mathematical models

Yang, Jianqing,Zhou, Jianrong,Zhang, Lianjun,Tan, Jinhao,Jiang, Xingfen,Zhou, Jianjin,Zhou, Xiaojuan,Hou, Linjun,Song, Yushou,Sun, XinLi,Zhang, Quanhu,Sun, Zhijia,Chen, Yuanbo Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.7

The ⁿMCP (Neutron sensitive microchannel plate) combined with advanced readout electronics is widely used in energy selective neutron imaging because of its good spatial and timing resolution. Neutron detection efficiency is a crucial parameter for the ⁿMCP. In this paper, a mathematical model based on the oblique cylindrical channel and elliptical pore was established to calculate the neutron absorption probability, the escape probability of charged particles and overall detection efficiency of ⁿMCP and analyze the effects of neutron incident position, pore diameter, wall thickness and bias angle. It was shown that when the doping concentration of the ⁿMCP was 10 mol%, the thickness of ⁿMCP was 0.6 mm, the detection efficiency could reach maximum value, about 24% for thermal neutrons if the pore diameter was 6 ㎛, the wall thickness was 2 ㎛ and the bias angle was 3 or 6°. The calculated results are of great significance for evaluating the detection efficiency of the ⁿMCP. In a subsequent companion paper, the mathematical model would be extended to the case of the spatial resolution and detection efficiency optimization of the coating ⁿMCP.

Study on the neutron imaging detector with high spatial resolution at China spallation neutron source

Jiang, Xingfen,Xiu, Qinglei,Zhou, Jianrong,Yang, Jianqing,Tan, Jinhao,Yang, Wenqin,Zhang, Lianjun,Xia, Yuanguang,Zhou, Xiaojuan,Zhou, Jianjin,Zhu, Lin,Teng, Haiyun,Yang, Gui-an,Song, Yushou,Sun, Zhiji Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.6

Gadolinium oxysulfide (GOS) is regarded as a novel scintillator for the realization of ultra-high spatial resolution in neutron imaging. Monte Carlo simulations of GOS scintillator show that the capability of its spatial resolution is towards the micron level. Through the time-of-flight method, the light output of a GOS scintillator was measured to be 217 photons per captured neutron, ~100 times lower than that of a ZnS/LiF:Ag scintillator. A detector prototype has been developed to evaluate the imaging solution with the GOS scintillator by neutron beam tests. The measured spatial resolution is ~36 ㎛ (28 line pairs/mm) at the modulation transfer function (MTF) of 10%, mainly limited by the low experimental collimation ratio of the beamline. The weak light output of the GOS scintillator requires an enormous increase in the neutron flux to reduce the exposure time for practical applications.

A novel ceramic GEM used for neutron detection

Zhou, Jianrong,Zhou, Xiaojuan,Zhou, Jianjin,Jiang, Xingfen,Yang, Jianqing,Zhu, Lin,Yang, Wenqin,Yang, Tao,Xu, Hong,Xia, Yuanguang,Yang, Gui-an,Xie, Yuguang,Huang, Chaoqiang,Hu, Bitao,Sun, Zhijia,Chen, Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.6

A novel ceramic Gas Electron Multiplier (GEM) has been developed to meet the demand of high counting rate for the neutron detection which is an alternative to ³He-based detector at China Spallation Neutron Source (CSNS). An experiment was performed to measure the neutron transmittance of ceramic-GEM and FR4-GEM at the small angle neutron scattering (SANS) instrument. The result showed the ceramic-GEM has higher transmittance and less self-scattering especially for cold neutrons. One single ceramic GEM could give a gain of 10²-10⁴ in the mixture gas of Ar and CO₂ (90%:10%) and its energy resolution was about 27.7% by using ⁵⁵Fe X ray of 5.9 keV. A prototype has been developed in order to investigate the performances of the ceramic GEM-based neutron detector. Several neutron beam tests, including detection efficiency, spatial resolution, two-dimensional imaging, and wavelength spectrum, were carried out at CSNS and China Mianyang Research Reactor (CMRR). The results show that the ceramic GEM-based neutron detector is a good candidate to measure the high intensity neutrons.

A novel compound heterozygous mutation of SLC12A3 gene in a pedigree with Gitelman syndrome and literature review

Minglan Yang,Ying Dong,Jianqing Tian,Li Yan,Yawen Chen,Huiying Qiu,Wei Liu,Yaomin Hu 한국유전학회 2020 Genes & Genomics Vol.42 No.9

Background Gitelman syndrome (GS) is a tubulopathy characterized by hypokalemia, hypomagnesemia, hypocalciuria and metabolic alkalosis, which is caused by mutations in SLC12A3 gene. Objective The objective of this study was to investigate the mutation of SLC12A3 gene in a pedigree with GS and analyzed the clinical manifestations. Methods Next-generation sequencing and Sanger sequencing were performed to explore the mutations of SLC12A3 gene in a GS pedigree that included a 59-year-old male GS patient and a total of 11 family members within three generations. Results A novel compound heterozygous mutation of SLC12A3 gene (c.1712T>C in exon14 and c.2986_2987ins GCT in exon26) was identifed by genetic testing in the proband. Moreover, we demonstrated that two brothers shared the same heterozygous mutation with the proband, but only one brother had the GS related symptoms. His nephew was the carrier of one mutation (c.1712T>C), and one of his brother, his sister and niece were carriers of the other (c.2986_2987ins GCT). Conclusions This is the frst study to report the novel pathogenic compound heterozygous mutation of SLC12A3 gene in GS. Our result further supports the lack of phenotype–genotype correlations in GS. Further functional studies are required to investigate pathophysiologic mechanisms of GS.

SP1-induced lncRNA MCF2L-AS1 promotes cisplatin resistance in ovarian cancer by regulating IGF2BP1/IGF2/MEK/ERK axis

Yan Zhu,Lijuan Yang,Jianqing Wang,Yan Li,Youguo Chen 대한부인종양학회 2022 Journal of Gynecologic Oncology Vol.33 No.6

Objective: Cisplatin resistance is a huge problem encountered in ovarian cancer treatment. Our study probed the roles and the underlying mechanisms of lncRNA MCF2L-AS1 in ovarian cancer cisplatin-resistance. Methods: SKOV3 and IGROV-1 cells were subjected to gradually increasing concentrations of cisplatin to construct ovarian cancer cisplatin-resistance cells. Cell proliferation was evaluated by cell counting kit-8 and colony formation assays. Cell apoptosis was assessed using Annexin V and PI staining. The relationships between SP1, MCF2L-AS1 and insulin-like growth factor-2 mRNA binding protein 1 (IGF2BP1) were verified by RNA pull-down, RIP, ChIP and dual- luciferase reporter gene assay, respectively. Tumor xenograft experiment was employed to evaluate the effects of MCF2L-AS1 silencing on ovarian cancer cisplatin-resistance in vivo. TUNEL staining and immunohistochemistry were performed in tumor tissue. Results: MCF2L-AS1 and IGF2BP1 were upregulated in cisplatin-resistant cells. MCF2L-AS1 silencing suppressed cell proliferation of cisplatin-resistant cells, while promoted the apoptosis, suggesting that MCF2L-AS1 knockdown suppressed ovarian cancer cells cisplatin-resistance. Meanwhile, MCF2L-AS1 silencing enhanced cisplatin sensitivity in ovarian cancer parental cells and IGF2BP1 overexpression impaired cisplatin sensitivity of parental cells. MCF2L-AS1 activated IGF2/ MEK/ERK pathway through interacting with IGF2BP1. Transcription factor SP1 activated MCF2L- AS1 expression. MCF2L-AS1 knockdown inhibited ovarian cancer cisplatin-resistance in vivo. Conclusion: SP1-induced MCF2L-AS1 promoted ovarian cancer cisplatin-resistance through activation of IGF2/MEK/ERK pathway via interacting with IGF2BP1.

A novel reconstruction algorithm based on density clustering for cosmic-ray muon scattering inspection

Hou, Linjun,Zhang, Quanhu,Yang, Jianqing,Cai, Xingfu,Yao, Qingxu,Huo, Yonggang,Chen, Qifan Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.7

As a relatively new radiation imaging method, the cosmic-ray muon scattering imaging technology can be used to prevent nuclear smuggling and is of considerable significance to nuclear safety. Proposed in this paper is a new reconstruction algorithm based on density clustering, aiming to improve inspection quality with better performance. Firstly, this new algorithm is introduced in detail. Then in order to eliminate the inequity of the density threshold caused by the heterogeneity of the muon flux in different positions, a new flux correction method is proposed. Finally, three groups of simulation experiments are carried out with the help of Geant4 toolkit to optimize the algorithm parameters, verify the correction method and test the inspection quality under shielded condition, and compare this algorithm with another common inspection algorithm under different conditions. The results show that this algorithm can effectively identify and locate nuclear material with low misjudging and missing rates even when there is shielding and momentum precision is low, and the threshold correcting method is universally effective for density clustering algorithms.

Optimization study of a clustering algorithm for cosmic-ray muon scattering tomography used in fast inspection

Hou, Linjun,Huo, Yonggang,Zuo, Wenming,Yao, Qingxu,Yang, Jianqing,Zhang, Quanhu Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.1

Cosmic-ray muon scattering tomography (MST) technology is a new radiation imaging technology with unique advantages. As the performance of its image reconstruction algorithm has a crucial influence on the imaging quality, researches on this algorithm are of great significance to the development and application of this technology. In this paper, a fast inspection algorithm based on clustering analysis for the identification of the existence of nuclear materials is studied and optimized. Firstly, the principles of MST technology and a binned clustering algorithm were introduced, and then several simulation experiments were carried out using Geant4 toolkit to test the effects of exposure time, algorithm parameter, the size and structure of object on the performance of the algorithm. Based on these, we proposed two optimization methods for the clustering algorithm: the optimization of vertical distance coefficient and the displacement of sub-volumes. Finally, several sets of experiments were designed to validate the optimization effect, and the results showed that these two optimization methods could significantly enhance the distinguishing ability of the algorithm for different materials, help to obtain more details in practical applications, and was therefore of great importance to the development and application of the MST technology.

Cardiac-derived stem cell engineered with constitutively active HIF-1a gene enhances blood perfusion of hindlimb ischemia

Xing Pei,Jiyoung Shin,김희정,Nana Wang,Chaewon Seo,Miyun Yoon,Xiongwen Chen,Jianqing Gao,Victor C. Yang,Huining He,Seungjin Lee 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.105 No.-

Stem cell-based therapeutic approach provides a possible treatment for critical limb ischemia (CLI) byinducing revascularization and regenerating ischemic tissue. However, the clinical benefit is modestdue to low cell survival and limited efficacy after transplantation. Cardiac-derived stem cells (CSCs) mightbe a novel cell source for CLI treatment owing to their superb endothelial differentiation potential andangiogenic paracrine functions. In this study, the angiogenic ability of CSCs was maximized by geneticengineering with constitutively active form of hypoxia-inducible factor-1a (CA-HIF-1a), resistant tooxygen-dependent degradation. CSCs transfected with CA-HIF-1a (CA-HIF-CSCs) promoted supplementaryexpression of proangiogenic factors including VEGF, bFGF, Ang-1 and PDGF-B, along with enhancedangiogenic function including migratory effect, tube formation and endothelial differentiation potential. In the mouse CLI model, CA-HIF-CSCs transplanted into the ischemic region using fibrin gel as cell deliveryvehicle, improved blood perfusion and limb functional recovery with minimal incidence of foot necrosisand limb loss by promoting new vessel formation. Histological evidence further confirmed that CAHIF-CSC/gel treatment markedly alleviated muscle degeneration and fibrosis. CSCs genetically engineeredwith constitutively active HIF-1a provide a novel therapeutic modality in CLI combining stem cell andgene therapy.