[en] Oxytocin a cyclic peptide whose sequence CYIQNCPLG was the first biologically relevant peptide to be synthesized. Synthesis by Boc strategy using p-methyl benzhydrylamine resin and also by Fmoc using Rink p-methyl benzhydrylamine resin was carried out with high yields. The crude peptide was cycled with 10% dimethylsulfoxide, characterized by mass spectrometry and nuclear magnetic resonance showing the presence of two isomers

[en] In Mexico, breast cancer is a public health problem, but is curable if diagnosed in early stages. For this, mammography is used, which is the early detection technique that has been shown to reduce mortality from this condition when performed with quality. To do this, you must have equipment that works correctly, that produces images with diagnostic quality, optimizing the radiation dose given to the patient. The objective of this work was to carry out quality control tests on two DR type digital mammography systems (E1 and E2). The tests were applied according to the protocols of the American College of Radiology (ACR) and the European Federation of Organizations for Medical Physics (EFOMP) 16 and 13 tests respectively. The results of all the tests are presented, in particular, for image quality according to ACR and EFOMP, both devices meet the mannequin score: fibers 4, micro-calcifications 4 and masses 4 for E1 and 3, 3 and 4 respectively for E2. The signal-to-noise ratio is met by E1 and E2, the contrast-to-noise ratio is met for E2 but not for E1, the images in E1 and E2 do not present artifacts. In relation to the average glandular dose, it is met by E1 and E2 according to ACR (0.95 ± 0.05 and 1.34 ± 0.08 mGy) and EFOMP (1.31 ± 0.07 and 1.16 ± 0.05 mGy) for the reference phantoms of each protocol. From the application of the protocols it can be conclude that the results obtained are similar, however the ACR protocol has more restrictive tolerances. In the ACR protocol it is easier to perform the required calculations and filling out your spreadsheet is simpler. On the other hand, the EFOMP spreadsheet has errors. (author)