Use of plutonium isotope activity ratios in dating recent sediments. [/sup 238/Pu//sup 239/Pu + /sup 240/Pu]

Graphic determination of isotope activity ratios in simultaneous assay of tritium and carbon-14

Analytical Biochemistry ◽

10.1016/0003-2697(67)90073-5 ◽

1967 ◽

Vol 18 (1) ◽

pp. 185-190 ◽

Cited By ~ 4

Author(s):

David P. Aikman ◽

Brian D. Patterson

Keyword(s):

Carbon 14 ◽

Activity Ratios ◽

Isotope Activity Ratios ◽

Graphic Determination

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Perspectives on the relationship between otolith growth and the conversion of isotope activity ratios to fish ages

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f95-820 ◽

1995 ◽

Vol 52 (10) ◽

pp. 2296-2303 ◽

Cited By ~ 9

Author(s):

Daniel K. Kimura ◽

Craig R. Kastelle

Keyword(s):

Growth Model ◽

Linear Growth ◽

Age Determination ◽

Growth Curves ◽

Otolith Growth ◽

Daunting Task ◽

Activity Ratios ◽

Linear Growth Model ◽

Isotope Activity Ratios ◽

The Relationship

Ageing of fish otoliths using radiometric methods is now becoming widely accepted. Using this methodology, one has the choice of extracting otolith cores or modeling otolith mass growth. Modeling otolith growth forgoes the difficult work of extracting cores, but one is left with the nearly equally daunting task of selecting and validating an otolith growth model and deriving the corresponding decay equations. We note that the mathematical aspects of this problem appear to have been satisfactorily resolved. However, problems of interpretation remain, and it is not clear whether practitioners fully appreciate the sensitivity of their results to growth model selection and interpretation. We note that the two-stage linear growth model appears to be generally misapplied in the literature. Also, we present evidence that the process of using otolith growth curves estimated from annular ring counts to validate the method of counting annular rings can constitute circular reasoning. Although tedious work, extracting otolith cores seems the most valid way to avoid some serious problems in radiometric age determination work.

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SEM study of quartz grains from recent sediments: Western Iraq

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010017743x ◽

1990 ◽

Vol 48 (4) ◽

pp. 860-861

Author(s):

F. Al-Kufaishi

Keyword(s):

Factor Loading ◽

Fault System ◽

Clay Material ◽

Crustal Material ◽

Factor Analyses ◽

Five Factors ◽

Sem Study ◽

Recent Sediments ◽

Quartz Grains ◽

Positive Factor

Two localities (Al-Marij and Laik) were selected to investigate the type of Quartz Grains from crustal material formed by evaporation of waters discharged by springs in Hit area, western Iraq, Previous studies on the crustal material (1,2) showed that the water discharged by these springs are associated with Abu-Jir fault system which run parallel to the Euphrates river,Factor analyses of the crustal and soil materials (50 samples analysed for 16 variables)(2) showed five factors; the first factor includes SiO2, Al2O3 and TiO2 with positive factor loading, and CaO, L.O.I. with negative loading and hence lead to the conclusion that the distribution of these variables is a reflection of transported clay material.This study concentrates on the use of SEM to investigate the contribution of Quartz grains found in the crustal material on two selected sites.

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Evaluation of 99mTc-Label led Vitamin K4 as an Agent for Testicular Imaging

Nuklearmedizin ◽

10.1055/s-0038-1629552 ◽

1991 ◽

Vol 30 (01) ◽

pp. 35-39 ◽

Cited By ~ 1

Author(s):

H. S. Durak ◽

M. Kitapgi ◽

B. E. Caner ◽

R. Senekowitsch ◽

M. T. Ercan

Keyword(s):

Soft Tissue ◽

Room Temperature ◽

Normal Subjects ◽

Left Testis ◽

Wide Range ◽

Activity Ratios ◽

The Right ◽

Radioactivity Levels

Vitamin K4 was labelled with 99mTc with an efficiency higher than 97%. The compound was stable up to 24 h at room temperature, and its biodistribution in NMRI mice indicated its in vivo stability. Blood radioactivity levels were high over a wide range. 10% of the injected activity remained in blood after 24 h. Excretion was mostly via kidneys. Only the liver and kidneys concentrated appreciable amounts of radioactivity. Testis/soft tissue ratios were 1.4 and 1.57 at 6 and 24 h, respectively. Testis/blood ratios were lower than 1. In vitro studies with mouse blood indicated that 33.9 ±9.6% of the radioactivity was associated with RBCs; it was washed out almost completely with saline. Protein binding was 28.7 ±6.3% as determined by TCA precipitation. Blood clearance of 99mTc-l<4 in normal subjects showed a slow decrease of radioactivity, reaching a plateau after 16 h at 20% of the injected activity. In scintigraphic images in men the testes could be well visualized. The right/left testis ratio was 1.08 ±0.13. Testis/soft tissue and testis/blood activity ratios were highest at 3 h. These ratios were higher than those obtained with pertechnetate at 20 min post injection.99mTc-l<4 appears to be a promising radiopharmaceutical for the scintigraphic visualization of testes.

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