Retrospective determination of fallout radionuclides and 236U/238U, 233U/236U and 240Pu/239Pu atom ratios on air filters from Vienna and Salzburg, Austria.

137Cs and 241Pu (via 241Am) concentrations were measured γ-spectrometrically on air filters from the early 1960s (mainly from 1964-66) from Vienna, Austria, and an alpine station in Salzburg, Austria. Accelerator mass spectrometry (AMS) was used to determine 240Pu/239Pu, 236U/238U and 233U/236U atom ratios as well as 236U, 239Pu and 240Pu atom concentrations. The maximum 236U/238U atom ratio of these unique undisturbed global fallout samples was (1.19 ± 0.31) × 10-5 in spring 1964. The 233U/236U atom ratios were found within (0.15-0.49) × 10-2 and indicate that the weapons tests of the early 1960s can be excluded as 233U source. The 236U/239Pu atom ratios were calculated in the range of 0.22-0.48.

Retrospective determination of U and Pu isotopes and atom ratios in lung samples from Vienna, Austria.

Uranium and plutonium isotope concentrations as well as 236U/238U and 240Pu/239Pu atom ratios were measured by AMS in human lung samples from the early 1960s. The 236U concentrations as well as the 236U/238U atom ratios show a maximum in 1964, 239Pu and 240Pu concentrations are increasing continually from 1962 to 1965. 236U/238U atom ratios are lower by two orders of magnitude compared to corresponding aerosol data from Vienna, probably due to older 238U deposited in the lungs, enhanced 238U concentrations in the city air, and activity partition within different particle sizes. The 236U/239Pu atom ratios in lung samples are also lower than expected from the aerosol data, while 240Pu/239Pu atom ratios lie well within the range typical for nuclear bomb fallout.

Laser-assisted management of ectopic eruption of permanent incisors.

Ectopic eruption originates from the malpositioning of a tooth bud ending in the eruption of the tooth in an improper direction. This anomaly is a consequence of ectopic development of the tooth germ. This condition gives rise to significant aesthetic and occlusal issues in the early mixed dentition stage. The most frequently influenced teeth are the maxillary first molars, accompanied by the maxillary cuspids. Ectopic eruption is seldom seen and might derive from traumatic injury. In some cases, hyperplastic and fibrotic gingival tissue may lead to ectopic eruption of a permanent incisor. Managing ectopically erupting teeth generally rests on several reasons including extraction of supernumerary tooth, removal of cyst and excision of hyperplastic tissue and subsequent to orthodontic movement of tooth if necessary. In this case, the use of Er, Cr: YSGG lasers for the correction of hyperplastic soft tissues involving ectopically erupting permanent incisors are depicted considering two cases.