Microwave ablation zones are larger than they macroscopically appear - Reevaluation based on NADH vitality staining ex vivo

Abstract

BACKGROUND: Animal liver is established as an ex vivo model for studies on hepatic microwave ablation (MWA). Macroscopically visible color changes in the ablation zone are used to assess cell destruction and confirm successful ablation ex vivo. OBJECTIVE: Macroscopy and histology of MWA zones regarding cell viability in ex vivo porcine livers were compared in this study. METHODS: Six MWA were performed in porcine livers post mortem. A 14-G antenna and microwave generator (928 MHz; 9.0 kJ) were used. MWA were cut at the maximum cross section in vertical alignment to the antenna. NADH-diaphorase staining determined cell vitality. Macroscopic and microscopic ablation zones were statistically analyzed. RESULTS: Histology showed two distinct ablation zones: central white zone (WZH) with no cell viability and peripheral red zone (RZH) with partial cell viability. However, the macroscopically visible WZM was significantly smaller than the microscopic WZH with an area difference of 43.1% (p < 0.05) and a radius difference of 21.2% (1.6 mm; p < 0.05). Macroscopy and histology showed a very high correlation for the complete lesion area (WZH/M+RZH/M; r = 0.9; p = 0.001). CONCLUSIONS:The avital central zone is significantly larger as the macroscopically visible WZ which is commonly used to assess successful ablation in MWA ex vivo studies. Irreversible cell destruction can be underestimated in macroscopic evaluation.

Supersymmetric S-matrices from the worldsheet in 10 & 11d

“…Reductions to other theories in d < 10, for example to the recent 6d superamplitudes of [15,[25][26][27], can be obtained [18]. Other directions include making contact with the semi-pure spinors of [1], the pure spinor framework in 10d and to extend the formulae to include brane degrees of freedom [19].…”

“…In the spinorial model, we expect that criticality requires a spinorial version of the integrand, similar to the reduced determinant of a matrix H ij forming the integrand in 4d and 6d [15]. We can indeed define an analogue of H ij in d = 10, 11, where each entry is now a matrix, H ab ij = ǫ a ia ǫ ab j , with the integrand a reduced quasi-determinant, [18].…”

“…In these, gravity amplitudes arise as a double copy of Yang-Mills amplitudes. Thus our integrands I n in (15) are constructed from reduced Pfaffians or determinants of the CHY matrix M in (18) or of the submatrix A, as well as the supersymmetric factors e F , Super Yang-Mills:…”

“…where ǫ a ia is the polarization data for the ith particle. It is a key fact that for each solution to the scattering equations k i · P (σ i ) = 0, there exists a unique λ aα satisfying (8) and (11), [18]. Briefly, this follows from a degree count of the subbundle E ⊂ S a where S a is the trivial bundle of spinors over CP 1 and E the subbundle that is annihilated by P m γ ab m .…”

“…Here the Z A α are worldsheet spinors, A αβ M are (0, 1)-form gauge fields on the worldsheet, and Γ M AB are the SO(13) gamma matrices. The A αβ M are Lagrange multipliers for the 13d semi-purity constraints Γ M AB Z A α Z B β = 0 that follow from the existence of (x µ , θ a , P µ ) such that the incidence relations (21) hold [18].…”