Neutron collimator design of neutron radiography based on the BNCT facility

Abstract

For the research of CCD neutron radiography, a neutron collimator was designed based on the exit of thermal neutron of the Boron Neutron Capture Therapy (BNCT) reactor. Based on the Geant4 simulations, the preliminary choice of the size of the collimator was determined. The materials were selected according to the literature data. Then, a collimator was constructed and tested on site. The results of experiment and simulation show that the thermal neutron flux at the end of the neutron collimator is greater than 1.0 × 10 6 n/cm 2 /s, the maximum collimation ratio (L/D) is 58, the Cd-ratio(Mn) is 160 and the diameter of collimator end is 10 cm. This neutron collimator is considered to be applicable for neutron radiography.

Role of Protein Tyrosine Phosphatase Receptor Type E (PTPRE) in Chemoresistant Retinoblastoma

“…It has been shown that PTPRE expression in murine mammary glands leads to massive hyperplasia and associated tumorigenesis [9] and high PTPRE expression in thyroid cancer correlates with tumor size [30]. In accordance with these findings, in our study presented, PTPRE depleted, etoposide resistant RB cells developed significantly smaller tumors in ovo than control cells, supporting the notion of PTPRE being an oncogene rather than a tumor suppressor in RB.…”

“…Overexpression of PTPRE was likewise reported for all stages of renal cell carcinoma [14]. Besides, PTPRE is highly expressed in thyroid cancer clinical samples and cell lines and overexpression correlates with TNM stage [30]. Fittingly, in the study presented, we likewise observed increased PTPRE expression levels in etoposide resistant compared to chemosensitive RB cell lines as well as in RB patient tumors compared to the healthy human retina.…”

“…As PTPs in general and PTPRE in particular have been controversially discussed as tumor suppressors or oncogenes [7,11,12,19], in the study presented we set out to investigate the functional effects of a PTPRE knockdown in etoposide resistant RB cell lines. Upregulated PTPRE has been shown to promote cell proliferation, whereas PTPRE KD resulted in the opposite effect indicating an oncogenic function in thyroid carcinoma [30]. Moreover, cells isolated from mammary tumors induced by Neu in mice genetically lacking PTPRE proliferated less than corresponding mammary tumor cells isolated from mice expressing the phosphatase [9].…”

“…Previous studies suggested an involvement of ERK1/2 in PTPRE downstream signaling [18,23,30]. The serotonin-tyrosine kinase ERK, phosphorylated and thereby activated by MEK, primarily plays a role in promoting cell proliferation and anti-apoptotic effects (for review see: [27]).…”

Non-destructive inspection of water or high-pressure hydrogen gas in metal pipes by the flash of neutrons and x rays generated by laser

“…Note that these images are snapshots in a single laser shot with a moderated neutron pulse of few μs and x ray with a width of ps. The spatial resolution is ∼0.2 cm, and it can be improved by using a collimator 34 in front of the samples. Due to low transmittances of thermal and epithermal neutrons for hydrogen, we can distinguish whether there is water in the pipe in the neutron image.…”