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Co content (x) dependences of cationic distribution and local fields at the tetrahedral A-site and octahedral B-site nuclei in Co ferrites, CoxFe3−xO4 (x = 0–1.0), were investigated by means of hyperfine interaction techniques. A combined investigation by 57Fe transmission and 57Co emission Mössbauer spectroscopies revealed that about 6% of Co2+ ions occupy the A sites for the sample with Co contents of x = 0 and 1.0. This observation evidently suggests that the site selectivity of Co2+ ions is independent of x for samples prepared on the same heat treatment condition. For hyperfine interaction parameters, obvious x dependence was observed for the B-site Fe nuclei, reflecting variation of the atomic ratio of Fe3+/Fe2+ changing with x, whereas for the A-site Fe nuclei, the parameters hardly change along with x. Contrary to the x-independence for the A-site Fe nuclei, however, it was demonstrated by perturbed angular correlation spectroscopy with the nonmagnetic probe 111Cd(←111In) that the hyperfine field at the A site significantly changes along with x. These contradictory results on the A-site fields verify that the nonmagnetic probe can distinguish a subtle change in the local fields with higher sensitivity. [ABSTRACT FROM AUTHOR]

The objective was to build a pelvic lymph node dissection support system using AI, evaluate the performance of the model, and verify whether this model provides an additional effect on physician organ recognition ability. This is a retrospective cohort study. Using image data from 263 cases of pelvic lymphadenectomy from a national multi-center surgical database (111 gynecology, 118 colorectal, 34 urology), totaling 19,301 images, we constructed four organ recognition models (ureter, obturator nerve, external iliac artery/vein) using Feature Pyramid Networks (FPN). Subsequently, total of 1,920 videos were then created, including videos with and without each organ present. Four obstetricians and gynecologists, two colorectal surgeons, two urologists. In the performance evaluation test, the accuracy of each organ was measured as Dice coefficient. In the additional evaluation test, surgeons were tested to determine the presence or absence of the organs and their locations in the videos without AI support. Next, the same test was conducted using videos with AI support. In the performance evaluation test, the Dice coefficients were: ureter 0.700, nerve 0.835, artery 0.864, vein 0.862. In the additional effect test, sensitivity increased significantly for all organs except the artery: ureter +20.0% (43.4% → 63.4%), nerve +7.2% (68.4% → 75.6%), artery +5.9% (69.7% → 75.6%), and vein +11.5% (69.1% → 80.6%). Specificity also improved: ureter +4.4% (86.9% → 91.3%), nerve +7.5% (85.3% → 92.8%), artery +1.9% (93.4% → 95.3%), and vein +7.9% (83.4% → 91.3%), with no decline due to AI support. The AI model showed a notable enhancement in surgeons' organ recognition ability. Future tests will involve surgeons of varying skill levels across three specialties to validate the model. [ABSTRACT FROM AUTHOR]

Magnetite (Fe3O4) was doped with radioactive 111mCd and 111In ions as impurities, and their residence sites and thermal stability were investigated by means of time-differential perturbed angular correlation (TDPAC) spectroscopy. Well-defined TDPAC spectra unequivocally show their sites: Cd ions are stably located only in the tetrahedral A site in all the temperature range of the present observation (77 K-873 K); In ions also specifically occupy the A site at low temperature, but at high temperature part of them select the B site in a reversible fashion. The energy difference between the A and B sites for the accommodation of In was experimentally determined to be 0.119 (9) eV by assuming a Boltzmann distribution for the populations of the 111In probe in the respective sites. The element-dependent thermal stabilities observed for Cd and In were well corroborated by density functional theory calculations. The successful observation of thermally activated site-tosite displacement of impurity In ions in Fe3O4 is reported. [ABSTRACT FROM AUTHOR]