[en] Digital Radiography (DR) is an effective method for nuclear facility security inspection. However, most of traditional DR systems employ one radiation source and one set of detectors, which can only obtain a projection image from one view of the object and possibly lose key information from other views. Most recently, dual-projection digital radiography inspection system has been developed to improve the ability of nuclear facility security to find dangerous materials, such as hidden nuclear waste and explosive of entry-exit vehicles. The attenuation coefficient is an important property to distinguish these dangerous materials, which can be obtained by a DR system under some conditions. Thus in this paper, we proposed a gradient descent iteration algorithm to reconstruct the shape and attenuation coefficient of the objects using two projection images from two different views under a certain constraint. The constraint requires that the cross section (geometry) in the ray plane of the object should be a convex polygon. The feasibility of the method has been proved by simulation experiments, while the application experiments based on the dual-projection digital radiography vehicle inspection system have also been taken. The Experiments show that the proposed method can effectively distinguish polycarbonate, graphite, aluminum, and water, of which the relative error of the attenuation coefficient and density can be less than 10%. (author)

[en] Advanced High Temperature Reactor (AHTR) is a type of the innovative Molten Salt Reactor (MSR) types which shows several promising characteristics such as high efficiency of thermal-electric conversion, high discharge burn-up and atmospheric pressure operation. However, due to the utilization of fuel assemblies with single enrichment, the power peaking factor (PPF) reaches to 2.09 with a radial PPF is more than 1.56, the high PPF is detrimental to the safety and economy of the reactor. We used a home-made AHTR-GATS code to minimize the PPF by radially varying the enrichment of fuel assemblies while keeping the FA average U-235 enrichment equal to the pre-design. To prevent the early convergence and obtain a better response, a novel hybrid algorithm which combines genetic algorithm (GA) with tabu search (TS) was developed to search for the best configuration corresponding to the desired patterns. The results indicated that compared with the pre-design the effective multiplication factor, k-inf of the optimized reactors were slightly improved and corresponding PPF were greatly reduced, and the temperature coefficient of reactivity were still negative throughout its lifespan. Moreover, the performance evaluation results of HAGATS show that it has strong robustness, high search efficiency and is suitable for loading pattern optimization. (author)

[en] [Background] As one of the important directions of machine learning, classification learning has great potential in industrial digital radiography, which can fully exploit different types of data features. Classification learning requires a large amount of labeled training data to train the prediction models. In view of the complex conditions of industrial digital radiography, obtaining complete training set samples by practical experiments is expensive and inefficient. [Purpose] This study aims to obtain complete training set data accurately and quickly by using simulation data. [Methods] First of all, numerical method was used to generate simulation data in corresponding scene. Then the training set for classification learning was established to be trained by using prediction model based on the Bagging Trees method and the KNN method. Finally, some of simulation data were assigned as test data set, and real industrial digital radiography data were used as verification data set to evaluate prediction models. [Results] The prediction accuracy of bagging trees method for the test set and verification set data is 99.6% and 81.25% respectively whilst KNN method for the test set and verification set data is 89.1% and 50% respectively. [Conclusion] The results show that the bagging trees method has a good effect on classification learning of radiography imaging based on simulation data. (authors)

[en] Objective: To study the clinical value of 64-slices spiral CTA with DSA comparatively in diagnosis of lower extremity arterial occlusive diseases. Methods: 31 patients with lower extremity arterial occlusive diseases underwent 64-slice spiral CT angiography of lower extremity arteries and they also underwent digital subtraction angiography (DSA)two weeks later. Reconstruction by maximum intensity projection (MIP), volume render (VR)and multiplanar reformatting (MPR)in working-station was undertaken comparing with the bolus chase DSA and traditional DSA for diagnostic accuracy. Results: The 216 arterial segments of lower extremity were selected, including 157 segments with consistent results in demonstrating degree of stenosis by both examinations. On CT angiography, 5 segmental stenosis were overestimated and 9 were underestimated. When stenosis of detected segments is more than 50%, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of CTA were 98.21%, 96.15%, 97.22%, 96.49%, and 98.04%, respectively. Conclusion: 64-slices spiral CT angiography is an effective and reliable method for evaluating the lower extremity arterial occlusive diseases and may provide precious information for planning interventional therapy. (authors)

No abstract available

[en] Purpose: This study was designed to evaluate the antitumorigenic efficiency of Endostar (an antiangiogenic agent) arterially administrated combined with transcatheter arterial chemoembolization (TACE) on liver tumor, and validation of perfusion CT for quantitative measurements of the results.Experimental DesignThirty rabbits bearing VX2 liver tumors were randomly and equally distributed into three groups. One of the following treatment protocols was performed in each group: 1) group 1 was treated with TACE and simultaneously arterially administrated Endostar; 2) group 2 with TACE alone, and 3) a control group that had saline injected through hepatic artery. Routine CT scan was performed before treatment, and perfusion CT imaging was performed 2 weeks after treatment. Immunohistochemical biomarkers of microvascular density (MVD) and the expression of vascular endothelial growth factor (VEGF) were measured for assessments of angiogenesis. Results: We observed a statistically significant reduction from the control in the volume, growth rate, and size of the tumor 2 weeks after treatment with both TACE plus Endostar and with TACE alone (P < 0.01). Although there was no statistically significant difference in tumor size between the group with TACE plus Endostar and the group with TACE alone (P > 0.05), MVD and VEGF were significantly less expressed in the TACE plus Endostar group than both groups with TACE alone and the control group (P < 0.01). Blood flow (BF), blood volume (BV), and permeability-surface area products (PS) in the group with TACE plus Endostar on perfusion CT were significantly higher than other two groups (P < 0.05), which were positively correlated with the MVD and VEGF values (P < 0.05). Conclusions: TACE with arterial administration of Endostar simultaneously significantly inhibited the angiogenesis biomarkers associated with TACE in a rabbit model bearing VX2 liver tumor, which indicates that the combined treatment protocol may have potential synergistic effects on liver cancer. It also is suggested that perfusion CT may be useful for monitoring antiangiogenic/antivascular treatment in the liver tumors.

[en] A growing number of electrochemical oxidation system was employed for the degradation of refractory contaminants. In this study, a boron-doped diamond (BDD) anode/Ti cathode equipped in the differential column batch reactor (DCBR) was utilized for electrochemical oxidation of ciprofloxacin (CIP). The feed solution within the DCBR system was confirmed as a uniform flow state through a computational fluid dynamics (CFD) simulation analysis. The results showed that the BDD anode/Ti cathode electrochemical system was with a high efficiency oxidation performance when treating the CIP contaminant. The CIP was completely degraded within 20 min, and over 50% DOC removed after 120 min. Therefore, two-stage electrochemical oxidation mechanism was proposed. Four major factors, the initial concentration, current density, pH, and electrolyte concentration, on the CIP degradation efficiency were systematically investigated. The CIP degradation curve followed pseudo first-order degradation kinetics. The electric efficiency per order (EE/O) of the electrochemical oxidation system was calculated to determine an optimal operation condition. Moreover, the oxidation intermediates were identified with a mass spectrometry (LC/MS/MS) and the degradation pathways were proposed in this study. The destruction of quinolone moiety and piperazine ring and fluorine substitution were the three possible degradation pathways during BDD anode oxidation process.

[en] The molten salt fast reactor (MSFR) shows great promise with high breeding ratio (BR), large negative temperature coefficient of reactivity, high thermal-electric conversion efficiency, inherent safety, and online reprocessing. Based on an improved MSFR optimized by adding axial fertile salt and a graphite reflector, the influences of ⁷Li enrichment on Th-U breeding are investigated, aiming to provide a feasible selection for the molten salt with high fissile breeding and a relatively low technology requirement for ⁷Li concentration. With the self-developed molten salt reactor reprocessing sequence based on SCALE6.1, the burn-up calculations with online reprocessing are carried out. Parameters are explored including BR, ²³³U production, double time (DT), spectrum, ⁶Li inventory, neutron absorption, and the tritium production. The results show that the ⁷Li enrichment of 99.95% is appropriate in the fast fission reactor. In this case, BR above 1.10 can be achieved for a long time, corresponding to the ²³³U production of 130 kg per year and DT of 36 years. After 80 years' operation, the tritium production for 99.5% is only about 7 kg, and there is no obvious increase compared to that for 99.9995%. (authors)

[en] Proteasomal subunit PSMB4, was recently identified as potential cancer driver genes in several tumors. However, the regulatory mechanism of PSMB4 on carcinogenesis process remains unclear. In this study, we investigated the expression and roles of PSMB4 in multiple myeloma (MM). We found a significant up-regulation of PSMB4 in MM plasma and cell lines. Ectopic overexpression of PSMB4 promoted cell growth and colony forming ability of MM cells, whereas inhibition of PSMB4 led to a decrease of such events. Furthermore, our results demonstrated the up-regulation of miR-21 and a positive correlation between the levels of miR-21 and PSMB4 in MM. Re-expression of miR-21 markedly rescued PSMB4 knockdown-mediated suppression of cell proliferation and clone-formation. Additionally, while enforced expression of PSMB4 profoundly increased NF-κB activity and the level of miR-21, PSMB4 knockdown or NF-κB inhibition suppressed miR-21 expression in MM cells. Taken together, our results demonstrated that PSMB4 regulated MM cell growth in part by activating NF-κB-miR-21 signaling, which may represent promising targets for novel specific therapies. - Highlights: • First reported upregulation of PSMB4 in MM plasma and cell lines. • PSMB4 promoted MM cell growth and colony forming ability. • Further found miR-21 was up-regulated by PSMB4 in MM plasma and cell lines. • PSMB4-induced miR-21 expression was modulated by NF-κB. • PSMB4-NF-κB-miR-21 axis may be potential therapeutic targets of MM

[en] Abstract Background: As the only one of liquid fuel reactor among the six candidate reactors chosen by the Generation IV International Forum (GIF), Molten Salt Reactor (MSR) shows great potential for future nuclear energy and thorium usage, especially for Molten Salt Fast Reactor (MSFR) with characters of high Th-U Breeding Ratio (BR) and large negative Temperature Coefficient of Reactivity (TCR). Purpose: Th-U breeding capacity of MSFR is expected to be further improved for more ²³³U production and shorter Double Time (DT), and burn-up analysis is necessary to demonstrate the breeding characters with time, as well as TCR for safety. Methods: Based on SCALE6.1, three aspects are explored including fertile in radial direction, newly added fertile in axial direction and appended graphite reflector, followed with explanations from the point of nuclide reaction rate. Furthermore, burn-up analysis is carried out with time by using the self-developed code Molten Salt Reactor Reprocessing Sequence (MSR-RS) specifically for on-line reprocessing of MSR. Results: Initial BR of 1.17 is obtained when axial fertile is included, and about 50% of fertile salt is saved with graphite reflector. BR above 1.1 in equilibrium and DT of 36 a are achieved, and the production of ²³³U is about 133 kg·a^-1, while TCR can be kept at about -6 × 10^-5 K^-1. Conclusion: Newly added axial fertile improves the BR obviously, while about half inventory of thorium can be saved with graphite reflector. The self-developed module MSR-RS is suitable for simulating the reprocessing of MSR, and ²³³U production for the optimized geometry increases markedly while TCR is kept negative enough at all the running time for safety. (authors)