Deep Inelastic Lepton Scattering in Nuclei at x > 1 and the Nucleon Spectral Function

The nuclear structure function F_2A(x) has been studied in the Bjorken limit for (l, l') scattering on nuclei in the region of x > 1 and was found to be very sensitive to the information contained in the nucleon spectral function in nuclei, particularly the correlations between momenta and energies in the region of large momenta. Calculations were done in a local density approximation using two different spectral functions for nuclear matter. Results are compared to those obtained for a spectral function which has been evaluated directly for the finite nucleus, ^{16}O, under consideration. For values of x around 1.5 and larger the quasiparticle contribution is negligible, thus stressing the sensitivity of the present reaction to the dynamical properties of nuclei beyond the shell model approach. Several approximations which are usually employed in studies of the EMC effect have been analyzed and their inaccuracy in this region is demonstrated. The results stress the fact that the nuclear structure function contains important information on nuclear dynamical correlations. Therefore further measurements of F_2A(x) in that region and for many nuclei would be most welcome.Comment: 24 pages, LaTeX, 11 PostScript figures, final version to appear in Nuclear Physics

Quasielastic Versus Inelastic and Deep Inelastic Lepton Scattering in Nuclei at x > 1

We have made a thorough investigation of the nuclear structure function W_2A in the region of 0.8 < x < 1.5 and Q^2 < 20 GeV^2, separating the quasielastic and inelastic plus deep inelastic contributions. The agreement with present experimental data is good giving support to the results for both channels. Predictions are made in yet unexplored regions of x and Q^2 to assert the weight of the quasielastic or inelastic channels. We find that at Q^2 < 4 GeV^2 the structure function is dominated by the quasielastic contributions for x < 1.5, while for values of Q^2 > 15 GeV^2 and the range of x studied the inelastic channels are over one order of magnitude bigger than the quasielastic one. The potential of the structure function at x > 1 as a source of information on nuclear correlations is stressed once more.Comment: 17 pages, LaTeX, 13 PostScript figures, final version to be published in Nuclear Physics

Oxidative stability and changes in the particle size of liposomes used in the Artemia enrichment

The oxidative stability and the particle size of several types of liposomes were assessed in order to characterize their behaviour when submitted to the aggressive conditions of the Artemia enrichments. Results show that all liposomes tested in this study were much more oxidatively stable than a commercial product based on fish oil emulsion. Whereas the initial thiobarbituric acid reactive substances (TBARS) concentration in the emulsion was only slightly higher than in liposomes, the concentration of TBARS in the emulsion increased up to values three orders of magnitude above those registered by liposomes after 21 h of incubation. Among the different liposome formulations, results indicate that vesicles composed of phospholipids containing long-chain highly unsaturated fatty acids (krill phospholipid extract) were generally less stable than those composed of shorter length-chain and more saturated acyl chains. In regards to the particle size changes during enrichment, all liposomes maintained their original size during the experimental period when incubated without nauplii. In the presence of nauplii, liposomes did not exhibit notable changes in their size, except for unilamellar vesicles prepared by the extrusion methodology and formulated with soybean phosphatidylcholine. The implications of the results on the capability of liposomes to be used in Artemia nauplii enrichments are discussed

Lipid peroxidation of a human hepatoma cell line (HepG2) after incorporation of linoleic acid, arachidonic acid, and docosahexaenoic acid

Lipid peroxidation of human heptoma cell line, HepG2, after incorporation of linoleic acid (LA), arachidonic acid (AA), and docosahexaenoic acid (DHA) was measured with a fluorescent probe and gas chromatography–mass spectrometry (GC–MS) analysis. The analysis with a fluorescent probe showed that incorporation of each polyunsaturated fatty acid (PUFA) enhanced the cellular lipid peroxidation level, but there was little difference in the effect of LA, AA, or DHA on the enhancement of cellular lipid peroxidation. The fluorescent analysis also showed that the addition of H2O2 (0.5 mM) enhanced the cellular lipid peroxidation levels in LA and AA supplemented cells as compared with those without H2O2. However, the enhancement of lipid peroxidation by H2O2 was not observed in DHA-supplemented cells. The same result was obtained in the GC–MS analysis of total amounts of monohydroperoxides (MHP) formed in the cellular phospholipid oxidation. In this case, the main source for MHP was LA in LA-, AA-, and DHA-supplemented cells. A significant amount of AA–MHP and a small amount of DHA–MHP were observed in AA- and DHA-supplemented cells respectively. GC–MS analysis also indicated the specific positional distribution of DHA–MHP isomers. The isomers were formed only by hydrogen abstraction at the C-18 (16-MHP + 20-MHP; 46.5%), C-6 (4-MHP + 8-MHP; 38.5%), and C-12 (10-MHP + 14-MHP; 15.1%) positions, but not at the C-9 or C-15 positions

The number of Japanese radiologic technologists will be increased in 40 years

It is essential to predict the long-term supply and demand for the number of radiologic technologists as medical resources. However, it is difficult to predict the number of Japanese radiologic technologists due to complex and intertwining factors. Our purpose in this study was to predict the future number of radiologic technologists using the concept of system dynamics (SD), and to clarify the effects of relevant factors. In order to estimate the number of Japanese radiologic technologists, we constructed a flow diagram using the concept of SD. We simulated the number of radiologic technologists for the following 4 cases: maintaining the status quo, a change in the pass rate for the national examination, a change in the post-graduate employment rate, and a change in the rate of continuing education. The result for the predicted number of radiologic technologists was 50,509 in 20 years, which is 4,394 (9.5 %) more than the present number, and 50,166 in 40 years, which is 4,051 (8.8 %) more than the present number. For the factors influencing the number of technologists, the influence of the pass rate on the national examination and that of the rate for post-graduate employment was larger than that of the rate of continuing education in graduate school. The number of Japanese radiologic technologists will increase until 2033 and decrease until 2042, and it does not change after 2042 in case of maintaining the status quo. Implementing the concept of SD allowed us easily to clarify the factors influencing the predicted number of radiologic technologists