Indirect CT-LG with iopamidol may have excellent potential for visualizing breast lymphatic drainage and for preoperative localization of breast sentinel lymph nodes.

Because preoperative CT lymphography-guided SLN mapping provides SLN position with detailed lymphatic anatomy, it may be useful for the direction of breast SLN biopsy.

The mechanism of tungsten (W) blistering under deuterium (D) plasma exposure is still under investigation. To clearly demonstrate the microstructure and nucleation mechanism of blistering on W exposed to D plasma, special recrystallized W disc samples were prepared and electropolished with back-thinned method for TEM observation. D plasma exposure (2.0  ×  1026 D m−2, 573 K) brought it numerous intra-granular blisters and protrusions on W with typical orientation dependence. TEM observation revealed the intra-granular blister microstructure that substantial dislocations were generated on the center and edge of blister via severe plastic deformation of blister cap. Dislocation tangles formed by dislocations from blisters were revealed and supposed to be the nucleation of intra-granular blister. By using the g · b  =  0 and g · b  ×  u  =  0 criterion, 〈0 0 1〉 dislocations with edge component were identified which were generated by 〈1 1 1〉 edge dislocation interaction in dislocation tangles. A {0 0 1}〈0 0 1〉 edge dislocation nucleating and blistering mechanism based on previous works is proposed, and by applying which blistering in recrystallized W could be well explained. Dedicated experiments demonstrated that intra-granular blister formation depends on local dislocation density which validated the mechanism.

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BACKGROUND AND PURPOSE Posterior fossa syndrome is a severe postoperative complication occurring in up to 29% of children undergoing posterior fossa tumor resection; it is most likely caused by bilateral damage to the proximal efferent cerebellar pathways, whose fibers contribute to the triangle of Guillain and Mollaret. When the triangle is disrupted, hypertrophic olivary degeneration develops. We hypothesized that MRI patterns of that reflect patterns of damage to the proximal efferent cerebellar pathways and show association with clinical findings, in particular the presence or absence of posterior fossa syndrome. MATERIALS AND METHODS We performed blinded, randomized longitudinal MRI analyses of the inferior olivary nuclei of 12 children with and 12 without posterior fossa syndrome after surgery for midline intraventricular tumor in the posterior fossa. Fisher’s exact test was performed to investigate the association between posterior fossa syndrome and hypertrophic olivary degeneration on MRI. Sensitivity and specificity of MRI findings of bilateral hypertrophic olivary degeneration for posterior fossa syndrome were measured. RESULTS Of the 12 patients with posterior fossa syndrome, 9 had bilateral inferior olivary nucleus abnormalities. The 12 patients without posterior fossa syndrome had either unilateral or no inferior olivary nucleus abnormalities. The association of posterior fossa syndrome and hypertrophic olivary degeneration was statistically significant (P < .0001). CONCLUSIONS Hypertrophic olivary degeneration may be a surrogate imaging indicator for damage of the contralateral proximal efferent cerebellar pathway. In the appropriate clinical setting, bilateral hypertrophic olivary degeneration may be a sensitive and specific indicator of posterior fossa syndrome.

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Doppler broadening spectroscopy in the positron annihilation technique (DBS-PA) has been employed to investigate the defect properties in argon-damaged tungsten exposed to low-energy and high flux deuterium plasma. Argon ion irradiations with energy 500 keV are performed for tungsten samples with various levels of damage. The remarkable increment of the S parameter in DBS-PA indicates the introduction of vacancy-type defects in argon irradiated tungsten. An increase of ion fluence results in a continuous increase of the S parameter until saturation. Unexpectedly, a much higher fluence leads to a decrease of the S parameter in the near surface, and the (S,W) slope changes greatly. This should be associated with the formation of argon-vacancy complexes in the near surface produced by the excessive implanted argon ions. With deuterium plasma exposure, a significant decrease of the S parameter occurs in the pre-irradiated tungsten, suggesting the sharp reduction of the number and density of the vacancy-type defects. The thermal desorption spectroscopy results demonstrate that the argon-damaged tungsten, compared to the pristine one, exhibits an enhanced low-temperature desorption peak and an additional and broad high-temperature desorption peak, which indicates that deuterium atoms are trapped in both low-energy and high-energy sites. All these observations directly indicate the deuterium occupation of irradiation-induced vacancy defects in damaged tungsten, which is responsible for the remarkable increase of the deuterium retention in comparison with the pristine one.

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