MCNP simulation and experimental study in situ low-grade copper analysis based on PGNAA.

A prompt gamma neutron activation analysis (PGNAA) facility utilizing 252Cf source has been developed for in situ analysis of copper samples. Monte Carlo simulation is employed to determine optimal sizes for neutron moderator, gamma-ray shielding material, and thermal neutron absorber. Subsequently, based on the parameters optimized by MCNP, the PGNAA facility was constructed. Five sets of experimental samples containing low-grade copper concentration of 0 %, 0.5 %, 1 %, 1.5 % and 2 % are measured with the PGNAA facility. The results show that the minimum detectable concentration of copper is 0.218 %. The maximum relative deviation of copper is 8.53 %.

Culture expansion of primary human nasal epithelial cells (NEC) isolated with a nasal scraping spoon.

OBJECTIVE: To obtain high-purity nasal epithelial cells (NEC) while avoiding the irritation experienced by patients during nasal biopsies. METHODS: This prospective, observational study enrolled patients undergoing surgical treatment for nasal septum deviation. After general anaesthesia, a novel nasal scraping spoon was used to collect epithelial cells from the mid-part of the inferior turbinate. The cells were evenly plated on six-well plates coated with rat tail collagen. The morphology and growth of the cells were observed at different time-points using an inverted phase-contrast microscope. Immunofluorescent staining of cytokeratin 18 was used to identify NEC. Ki67 staining was used to check cell viability. RESULTS: This study collected samples from 19 patients during a short procedure. No postoperative complications were observed. Cell samples ranging from 8.31 × 105 to 2.04 × 106 cells/sample were obtained. The culture model was suitable for primary NEC culture as demonstrated by the faster proliferation (5-7 days). There was no fungal or bacterial contamination. Immunofluorescent staining confirmed the presence and proliferative activity of NEC in the cultures. CONCLUSION: A novel nasal scraping spoon provided an easy sampling method, avoided nasal injuries and psychological barriers to sampling and sufficient viable NEC to establish primary cultures.