Noise-immune cavity-enhanced optical heterodyne detection of HO2 in the near-infrared range.

Accurate measurements of the absolute concentrations of radical species present in the atmosphere are invaluable for better understanding atmospheric processes and their impact on Earth systems. One of the most interesting species is HO(2), the hydroperoxyl radical, whose atmospheric daytime levels are on the order of 10 ppt and whose observation therefore requires very sensitive detection techniques. In this work, we demonstrate the first steps toward the application of external-cavity diode-laser-based noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) to the detection of the HO(2) radical in the near-infrared range. Measurements of stable species and of HO(2) were made in a laboratory setting, and the possibilities of extending the sensitivity of the technique to atmospheric conditions are discussed.

Second primary tumors in children and young adults in the North of England (1968-99).

BACKGROUND: This study describes the risk of second malignancy in patients diagnosed with cancer under the age of 25 years, registered on the Northern Region Young Person's Malignant Disease Registry. PROCEDURE: Incidence rates were calculated to describe the occurrence of second malignancies, rate ratios were estimated to compare rates between subgroups. Standardized incidence ratios (SIRs) were calculated for comparison with a reference population. RESULTS: There were 4,072 children and young adults diagnosed with a first malignancy from 1968 to 1999, of whom 68 had a second malignancy (including basal cell carcinomas and meningiomas). The incidence rate of second malignancy is 1.7 per 1,000 survivor person-years (95% CI: 1.4, 2.2), reflecting a four-fold increased risk of malignancy compared with the general population. The rate of second malignancy was non-significantly higher for those diagnosed during young adulthood rather than childhood (RR = 1.2, 95% CI: 0.7, 2.0), significantly higher in females than males (RR = 1.8, 95% CI: 1.1, 3.0) and significantly lower for those diagnosed in more recent years (RR = 0.4, 95% CI: 0.2, 0.8). In contrast, the SIRs indicated that children were at substantial increased risk; whilst males and females, and those diagnosed in earlier and later time periods, were at equivalent risks. CONCLUSIONS: There is evidence of a sustained increased risk of second malignancy in those treated for primary cancer, especially those diagnosed in childhood; with no evidence that this risk is reducing.