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Biomedical subjects

F Garcias

Publications and source records attributed to F Garcias.

12 recordsLinked to original sources
PubMed2001

Dissociation of vertical semiconductor diatomic artificial molecules.

We investigate the dissociation of few-electron circular vertical semiconductor double quantum dot artificial molecules at 0 T as a function of interdot distance. A slight mismatch introduced in the fabrication of the artificial molecules from nominally identical constituent quantum wells induces localization by offsetting the energy levels in the quantum dots by up to 2 meV, and this plays a crucial role in the appearance of the addition energy spectra as a function of coupling strength particularly in the weak coupling limit.

Journal Article↗
PubMed2000

Rapid 90Sr/90Y determination in water samples using a sequential injection method

We have developed a semiautomatic procedure based on a sequential injection method for 90Sr/90Y determination that allows their radiochemical separation in about 30 min. The method has been tested using 90Sr/90Y solutions with activities lower than 12 Bq. The source is eluted in a pH = 6.5 medium through a MnO2-impregnated cotton filter, where 9OY is preconcentrated in preference by adsorption. 90Y is extracted from the column with hydroxylamine, some 90Sr in the leached solution has also been found. After the radiochemical separation, the total beta-activity of the leached solution has been determined using a low background alpha-beta proportional counter and, assuming the presence of 90Sr and 90Y at t = 0, the solution of the Bateman equations allows the initial concentration of both isotopes to be obtained. We have verified that the addition of some ions usually found in water samples (Cl-, HCO3-, NO3-, SO4(2-), Ca2+, Mg2+) does not interfere with the yield of the radiochemical process, (90 +/- 10)%. The method has been applied to 90Sr/90Y determination in mineral waters, and even in thermal waters, where the salt concentration can be about 3500 mg/l, the radiochemical yield remains greater than 80%.

Journal Article↗
PubMedDate not supplied

Multisyringe flow injection analysis of stable and radioactive strontium in samples of environmental interest.

A multisyringe flow injection (MSFIA) method for the determination of stable and radioactive strontium, using a solid phase resin (Sr-Resin), has been developed. Strontium concentrations are determined by atomic emission spectroscopy and by a low background proportional counter. The method has been applied to different samples (water, milk and soil) of environmental interest. The LLD of the stable and radioactive Sr were 10 microg/l and 0.01 Bq, respectively. The standard deviation of the separation procedure is 2% (n=10).

Animals↗