The knowledge about a seed's optical parameters is of great relevance in the seed technology practice. Such parameters provide information about its absorption and reflectance, which in turn is related to its color, quality, and health condition. The objective of the present study was to determine the optical absorption coefficient β for maize seeds (Zea mays L.) by means of the photoacoustic spectroscopy (PAS). Untreated seeds (I) and seeds dyed with methyl red (II) were used in this investigation. In addition, conventional reflectance measurements (obtained with the integrating sphere) were performed to validate PAS absorption measurements. The results show that the absorption spectra and reflection data of the seed samples are complementary. When used with thermally thick and optically opaque seeds, PAS may be considered as a potential diagnostic tool for the characterization of the seeds.
The gene encoding thymidine kinase 1 from tomato (toTK1) has in combination with azidothymidine (AZT) recently been proposed as a powerful suicide gene for anticancer gene therapy. The toTK1/AZT combination has been demonstrated to have several advantages for the treatment of glioblastomas because AZT can easily penetrate the blood-brain barrier and toTK1 can efficiently phosphorylate AZT and also AZT-monophosphate. In a pursuit to further understand the properties of toTK1, we examined the oligomerization properties of recombinant toTK1 and its effect on enzyme kinetics. Previously, it has been shown that human TK1 is a dimer in the absence of ATP and a tetramer if preincubated with ATP. However, we show here that ATP preincubation did not result in a structural shift from dimer to tetramer in toTK1. For human TK1 pretreated with ATP, the K(m) value decreased 20-fold, but toTK1's K(m) value did not show a dependence on the presence or absence of ATP. Furthermore, toTK1 was always found in a highly active form.
Se analiza la incidencia del tipo de cáncer y sus principales manifestaciones en la etapa terminal mediante la minería de datos. Se analizaron 288 datos de 22 pacientes, los cuales proporcionó la unidad de cuidados paliativos del Hospital Regional 1° de Octubre. Las variables evaluadas fueron género, año, edad, diagnóstico y síntoma. Para la clasificación se utilizó el algoritmo J48 correspondiente al algoritmo C4.5. La mayor incidencia de mortalidad, de acuerdo con el tipo de cáncer, se da en el de pulmón, colon, recto, mama y el de próstata. En cuanto al dolor, se presenta en mayor medida en pacientes jóvenes, mientras que en pacientes de 65 años o menos 39% y sólo en 23% de los restantes.
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