Application of Industrial Standard Methods for Detection of Horse- and Donkey-Derived Ingredients for Detecting Mule Meat

Both horse- and donkey-derived ingredients have been detected in mule meat by real-time polymerase chain reaction (PCR) as described in China’s industry standards for detection of horse (SN/T 3730.5-2013) and donkey (SN/T 3730.4-2013) ingredients in food and feed, respectively. This contradicts the theory of strict maternal inheritance of mitochondrial DNA (mtDNA). Therefore, in this study, 3 horse meat samples, 3 donkey meat samples and 3 mule meat samples were detected by mitochondrial gene and nuclear gene sequencing based on PCR and the China’s industry standard methods for horse and donkey ingredients, respectively, and the results of the SN/T 3730.4-2013 method for mule meat were analyzed. According to the results of mitochondrial gene and nuclear gene sequencing, all 3 mule meat samples were derived from mules. Both donkey and horse ingredients were detected in the 3 mule meat samples by the SN/T 3730.4-2013 and SN/T 3730.5-2013 methods. The cycle threshold (Ct) of the SN/T 3730.5-2013 method for horse ingredient was in the range of ≤ 20.00, and that of the SN/T 3730.4-2013 method for donkey ingredient were in the range of 25.00-35.00. The sequencing results of PCR products using the primers described in the SN/T 3730.4-2013 method showed that the 3 mule meat samples had no homology with horse or donkey meat. This might be because the SN/T 3730.4-2013 target sequence appeared in the form of nuclear mitochondrial DNA segments in low repeat numbers in the mule nuclear genome, and some base insertions and deletions occurred. The possibility that mule ingredient may be present should be considered when the Ct value of the SN/T 3730.4-2013 is ≤ 20.00, while the Ct value of the SN/T 3730.5-2013 is in the range of 25.00-35.00 for horse and donkey ingredients in known samples of single animal-derived ingredients, respectively

Development and evaluation of a real-time recombinase-aid amplification assay for rapid detection of Pseudomonas aeruginosa

Objective To establish a real-time recombinase-aid amplification (RAA) method for rapid detection of Pseudomonas aeruginosa. Methods Specific primers and exo probes based on ecfX gene of P. aeruginosa were designed in this study, and the validity of the method was evaluated by sensitivity, specificity and suspected strains detection. Results Real-time RAA was performed successfully at 39℃ for 20 min. Only the P. aeruginosa strains but not other bacteria were amplified, showing the good specificity. The limit of detection was 3.0×103 fg genomic DNA per reaction, and 1.0×103 CFU P. aeruginosa pure culture per reaction. The developed real-time RAA was further evaluated on 36 suspected of P. aeruginosa, which were identified successfully to be P. aeruginosa.The detection result were the same with those of a real-time PCR assay and the VITEK 2 Compact. Conclusion The developed real-time RAA assay is a rapid, simple and reliable tool for accurate detection of P. aeruginosa of diverse origins

Stress analysis of aspherical TRISO-coated particle with X-ray computed tomography

The failure probability of TRISO-coated particle is directly dependent on the asphericity and the layer thickness. Local asphericity of the SiC layer will contribute to the concentrated stress region, increasing failure probability of the particle. In this paper, we utilized micro X-ray computed tomography (CT) to obtain the 3D volume rendering of the SiC layer with the real geometric shape before irradiation. The stress distribution of the aspherical reconstructed SiC was then simulated with finite element method (FEM) based on the pressure vessel model. The maximum and mean principle stress were compared between the analytical methods and FEM simulation. The maximum deviation between the SiC principle stress with the real shape and ideal shape is 64.56 % for the inner gas pressure 17 MPa. The preliminary failure probability using the aforementioned stress was calculated and compared with the analytical solution. There is obvious increment with the maximum principle stress. The local stress concentration of the acquired aspherical model is 1.86. The stress discrepancy between the FEM simulation and the theoretical calculation increases with the inner gas pressure. The SiC asphericity measured with X-ray CT will contribute to a higher failure probability under irradiation

Three-Dimensional Measurement of TRISO Coated Particle Using Micro Computed Tomography

The fuel safety and performance of high-temperature gas-cooled reactor (HTGR) are dependent on the integrity and geometric parameter of Tri-structural Isotropic (TRISO) coated particle. Micro X-ray computed tomography (CT) was used for nondestructive testing and three-dimensional measurement of the particle components which are composed of kernel, buffer layer, inner pyrolytic carbon layer (IPyC), silicon carbide (SiC) layer, and outer pyrolytic carbon (OPyC) layer. The thickness distribution and volume of kernel and coating layers are obtained by constructing 3D volume rendering of TRISO particle. Mean thickness of each layer is calculated for comparison with design value. A comparison between two-dimensional and three-dimensional measurement results is also made. It is found that the thickness distribution of all layers approximately obeys Gaussian distribution. Deviation of the thickness of kernel and coating layers between 3D measurement result and design value is 7.88%, -25.63%, -45.50%, 13.87%, and 14.73%, respectively. The deviation will affect the failure probability of TRISO particle. Obvious difference of the OPyC mean thickness between 3D measurement and 2D measurement is found, which proves that the proposed 3D measurement provides comprehensive information of the particle. However, 2D and 3D measured thickness of the kernel and IPyC layer tend to be similar

3D Proton Bragg Peak Visualization and Spot Shape Measurement with Polymer Gel Dosimeters

Proton pencil beam scanning is a dynamic beam delivery technique with excellent conformability to the tumor volume. The accuracy of spot size and scanning positions will have a significant effect on the delivered dose distribution. We employed polymer gel dosimeters to measure the spot size and the scanning positions for the Shanghai Advanced Proton Therapy facility (SAPT). Polymer gel dosimeters (MAGAT-f and PAGAT) were utilized to measure the full width at half maximum (FWHM) of the beam spot at various depths on the basis of their MRI readouts. The correlation between the spot FWHM and standard deviation (σ) was analyzed at different depths. The measured Bragg peak range was compared with the Monte Carlo (MC) simulation. Three-dimensional volume rendering of the Bragg peak was reconstructed for the 3D visualization to measure the spot size three-dimensionally. The R2 dose–response curve was investigated with polymer gel dosimeters. The deviations of the Bragg peak ranging between measurement and simulation were 0.13% and −0.53% for MAGAT-f and PAGAT, respectively. Our results ascertain the feasibility of a polymer gel dosimeter to measure the spot size and positions of a proton pencil beam

Dose-Area Product Determination and Beam Monitor Calibration for the Fixed Beam of the Shanghai Advanced Proton Therapy Facility

Research conducted to-date, makes use of the IBA-Lynx scintillating screen and radiochromic film to analyze the proton field uniformity for dose-area product (DAP) determination. In this paper, the machine log file based reconstruction is proposed to calculate the field uniformity to simplify the measurement. In order to calculate the field uniformity, the dose distribution is reconstructed based on the machine log file with matRad (an open source software for analytical dose calculation in MATLAB). After acquisition of the dose distribution, the field flatness and symmetry are calculated automatically for different proton energies. A comprehensive comparison of DAP determined with Bragg peak chamber (BPC) and Markus chamber (MC) is presented. The actual delivered dose is reconstructed with the log file to analyze the lateral dose distribution of the scanned field. DAP of different energies are calculated ranging from 70.6 MeV to 235 MeV. The percentage difference is calculated, illustrating the DAP discrepancy between the MC and BPC to the mean value. The percentage difference ranges from −0.19% to 1.26%. The variation between DAP measured with the BPC and MC peaks at −2.5%. The log file based reconstruction to calculate field uniformity can be an alternative for DAP determination. The direct method using a large-area Bragg peak chamber is investigated. The two methods to determine DAP and calibrate beam monitor illustrate consistent results

18F-FDG PET/CT-based metabolic metrics in recurrent tumors of ovarian clear cell carcinoma and their prognostic implications

Abstract Background Glucose metabolism has been suggested as a therapeutic target in ovarian clear cell carcinoma (CCC). We attempted to clarify 18F-FDG PET/CT-based metabolic metrics in the recurrent ovarian CCC patients and their prognostic values. Methods Quantitative metabolic parameters included maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV) and total lesion glycolysis (TLG). Two different methods were employed for defining the threshold SUV to delineate MTV: 1) SUV of 2.5 (designated as MTV); 2) a fixed ratio including 40% (MTV40), 50% (MTV50) and 60% (MTV60) of SUVmax. The Kaplan-Meier model and Cox regression were used in survival analysis. Results Among the 35 patients, platinum-resistant recurrence accounted for 34.3% and the median progression-free survival was 13 months (range, 2–135). Fifteen (42.9%) patients presented with single tumor recurrence, while 51 recurrent lesions were identified, with the most common sites in pelvis (29.4%), followed by lymph node metastases (19.6%) and peritoneal carcinomatosis (15.7%). Except four patients with FDG-inavid tumor, the median SUVmax of the 31 patients with high glucose metabolic activity was 7.10 (range, 3.00–20.60). After a median follow-up of 36.5 months (range, 7–155), 22 patients (64.7%) were dead from disease. The median post-relapse survival (PRS) was 17 months (range, 4–126). Platinum-resistant recurrence, peritoneal carcinomatosis and high TLG60 proved to be negative predicators of overall survival after multivariate analysis. Conclusions TLG60, platinum-resistant recurrence and peritoneal carcinomatosis were independent negative predicators of overall survival. Whether patients with higher TLG60 required more aggressive treatment warranted further study

Diaphragmatic Surgery and Related Complications In Primary Cytoreduction for Advanced Ovarian, Tubal, and Peritoneal Carcinoma

Abstract Background To evaluate the procedures and complications of diaphragm peritonectomy (DP) and diaphragm full-thickness resection (DFTR) during primary cytoreduction for advanced stage epithelial ovarian cancer. Methods All the patients with epithelial ovarian carcinoma who underwent diaphragm procedures at our institution between January 2009 and August 2015 were identified. Clinicopathological data were retrospectively collected from the patients’ medical records. Postoperative morbidities were assessed according to the Memorial Sloan-Kettering Cancer Center (MSKCC) grading system. Results A total of 150 patients were included in the study. The majority of the patients had ovarian cancer (96%), stage IIIC disease (76%) and serous histology (89.3%). DP and DFTR were performed in 124 (82.7%) and 26 (17.3%) patients, respectively. A total of 142 upper abdominal procedures in addition to the diaphragmatic surgery were performed in 77 (51.3%) patients. No macroscopic residual disease was observed in 35.3% of the patients, while 84% of the total patient cohort had residual disease ≤1 cm. The overall incidence of at least one major morbidity (MSKCC grades 3–5) was 18.0%, whereas pleural effusions (33.3%), pneumonia (15.3%) and pneumothorax (7.3%) were the most commonly reported morbidities. The rate of postoperative pleural drainage was 14.6% in total, while half the patients in the DFTR group received drainage intraoperatively (11.5%) and postoperatively (38.5%). The incidence of postoperative pleural effusion was associated with stage IV disease (hazard ratio [HR], 17.2; 95% confidence interval [CI]: 4.5–66.7; P < 0.001), DFTR (HR, 4.9; 95% CI: 1.2–19.9; P = 0.028) and a long surgery time (HR, 15.4; 95% CI: 4.3–55.5; P < 0.001). Conclusions Execution of DP and DFTR as part of an extensive upper abdominal procedure resulted in an acceptable morbidity rate. Pleural effusion, pneumonia and pneumothorax were the most common pulmonary morbidities. The pleural drainage rate was not high enough to justify prophylactic chest tube placement for all the patients. However, patients who underwent DFTR merited special consideration for intraoperative prophylactic drainage

Uniformity Assessment of TRISO Fuel Particle Distribution in Spherical HTGR Fuel Element Using Voronoi Tessellation and Delaunay Triangulation

Nonuniform distribution of tri-structural-isotropic (TRISO) fuel particles in a spherical fuel element (SFE) may increase the failure probability of the SFE in the high-temperature gas-cooled reactor, leading to the release of fission products. To evaluate the uniformity of the TRISO particles nondestructively, 3-dimensional cone-beam computed tomography is used to image the SFE, and TRISO particles are segmented. After TRISO particle positions are identified, the Voronoi tessellation and Delaunay triangulation are used to extract several geometric metrics. Results indicate that both the Voronoi volume distribution and the nearest neighbor-distance distribution follow the log-normal distributions, which provide strong evidence that the TRISO particles are approximately randomly uniformly distributed. Further study will be focused on validating the conclusion with more SFE data