Detection of iron atoms by emission spectroscopy and laser-induced fluorescence in solid propellant flames.

Planar laser-induced fluorescence on atomic iron is investigated in this paper, and a measurement strategy is proposed to monitor the fluorescence of iron atoms with good sensitivity. A model is proposed to fit the experimental fluorescence spectra, and good agreement is found between simulated and experimental spectra. Emission and laser-induced fluorescence measurements are performed in the flames of ammonium perchlorate composite propellants containing iron-based catalysts. A fluorescence signal from iron atoms after excitation at 248 nm is observed for the first time in propellant flames. Images of the spatial distribution of iron atoms are recorded in the flame in which turbulent structures are generated. Iron fluorescence is detected up to 1.0 MPa, which opens the way to application in propellant combustion.

Histological study of stem-like cells in human colon adenocarcinoma at different stages of the disease.

The presence of stem-like cells in tumors reflects the invasive character of the disease; however, their identification is controversial. We investigated the distribution of CD133, CD44 and CD24 using histological sections and tissue microarrays (TMAs) of human colon adenocarcinoma obtained from patients with and without lymph node metastases and/or liver metastases. Immunohistochemical staining was combined with nuclear staining and evaluated quantitatively using image analysis software. Sections of normal colon mucosa, the primary tumor, lymph node, and liver also were analyzed qualitatively and compared to the quantitative method, which was more accurate. In most tissues, the expression of CD44 and CD24 was relatively low compared to CD133, with some variations. CD133 also was expressed in the normal colon mucosa and to a lesser degree in normal hepatic parenchyma. Liver metastases exhibited significantly greater CD133 staining compared to normal colon mucosa, primary tumor and lymph node metastases. Moreover, lymph node metastases obtained from patients with liver metastases expressed significantly greater CD133 staining than those obtained from patients without liver metastasis. Our data suggest that CD133 expression in lymph node metastases may be of value for prognosis of the disease.