Application of Volumetric Modulated Arc Therapy and Simultaneous Integrated Boost Techniques to Prepare "Safe Margin" in the Rabbit VX2 Limb Tumor Model.

Background: In this study, we aimed to establish the rabbit VX2 limb tumor model, and then prepare a "necrotic zone" as a safe margin by volumetric modulated arc therapy and simultaneous integrated boost (VMAT-SIB) technique applied in the areas where the tumor is located adjacent to the bone (GTVboost area).

Material And Methods: Rabbits in the control group (n=10) were not treated, while those in the test group (n=10) were treated with the SIB schedule delivering a dose of 40Gy, 35Gy, 30Gy, and 25Gy to the GTVboost, GTV (gross tumor volume), CTV (clinical target volume), and PTV (planning target volume) in 10 fractions. Magnetic resonance diffusion-weighted imaging (MRDWI), 3-dimensional power Doppler angiography (3D-PDA), and histological changes were observed after radiotherapy.

[Effects of nitrogen application rate and post-anthesis soil moisture content on the flag leaf senescence and kernel weight of wheat].

A rain-proof pool culture experiment was conducted to study the effects of nitrogen (N) application rate and post-anthesis soil moisture content on the flag leaf senescence and kernel weight of wheat. The results indicated that in all N fertilization treatments, the flag leaf SPAD value, soluble protein content, SOD and CAT activities, and photosynthetic rate decreased in the order of 60% -70% > 80%-90% >40%-50% post-anthesis soil moisture content, while the MDA content decreased in reverse order, suggesting that over high or low post-anthesis soil moisture content could cause the early senescence of flag leaves, impact grain filling, and decrease kernel weight. Under the same post-anthesis soil moisture content, the SPAD value, soluble protein content, SOD and CAT activity, and photosynthetic rate increased, while the MDA content decreased with increasing N application rate, indicating that increased N fertilization could postpone the senescence of wheat flag leaves.