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Abstract  

The applicability of the14N(p,p’ γ1)14N nuclear reaction in the determination of the absolute abundance of14N, with a 2% uncertainty, was demonstrated at 4.3 MeV bombarding energy. The fact that almost all of the thick target γ-ray yield resulted from a resonance at Ep=4.0 MeV allowed to consider the necessary stopping-power corrections only at the energy of that resonance. Alternatively, the method was used to obtain the stopping power of 4.0 MeV protons in complex biological materials.

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Background: Monitoring the retinal nerve fibre layer thickness (RNFLT) is essential in the diagnosis and treatment of glaucoma. In a previous study we found that a decrease of the polarimetric RNFLT observed in the early period after laser-assisted in situ keratomileusis (LASIK) disappears or tends to disappear by the third post-LASIK month. Purpose: To study the stability of the “recovered” polarimetric retardation values between the third and twelfth month after LASIK. Methods: Scanning laser polarimetry (SLP) with the classic GDx Nerve Fiber Analyzer was performed on 13 consecutive healthy subjects with no eye disease who underwent LASIK for ametropia correction. Measurements were performed preoperatively, then at 3 and 12 months postoperatively. Results: Inferior, temporal and nasal average thickness as well as ellipse average thickness and average thickness showed no difference among the three time points (ANOVA, p ? 0.05). Superior average thickness was significantly smaller both at three months (Sheffe test, p = 0.008) and 12 months (p = 0.006) than before LASIK. However, no difference was seen between the values measured at three months and at 12 months after LASIK (p = 0.997). A statistically significant interaction between treatment type (myopic or hyperopic correction) and the change of retardation was found for the superior average thickness (two-way ANOVA, p = 0.016). In this quadrant the RNFLT values of the myopic eyes decreased between the baseline and the month 3 measurements but became stable after that; the retardation of the hyperopic eyes remained unchanged throughout. Conclusion: RNFLT measured with the classic GDx device after LASIK shows transient changes probably due to the LASIK-induced alteration of the polarization and the healing process. The polarimetric RNFLT values, however, become stable by the third post-LASIK month, and show no further change until the end of the first year after LASIK. Baseline SLP measurements for long-term glaucoma follow-up can be obtained from the third post-LASIK month onwards.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
V. Papassotiriou
,
S. Georgala
,
J. Stratigos
,
N. Panayotakis
,
A. Hadjiantoniou
, and
A. Katsanos

Abstract  

Skin tissue samples from 41 patients suffering from skin epitheliomas were analyzed by the PIXE method. Skin samples from the non-affected areas and blood serum were also analyzed for the same patients. The elements determined were K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, and Pb. Their concentrations in the healthy skin and the serum were normal. The concentrations in the lesions were nearly the same for both basal cell and squamus cell epitheliomas (BCE and SCC) except for higher zinc and lower bromine values in the BCE samples. However, substantial differences were observed between the affected and non-affected skin.

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