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Benign Neoplasms
Published in Ayşe Serap Karadağ, Lawrence Charles Parish, Jordan V. Wang, Roxburgh's Common Skin Diseases, 2022
Abdullah Demirbaş, Ömer Faruk Elmas, Necmettin Akdeniz
Prognosis: Although lesions are benign tumors, secondary tumors, such as Bowen disease, BCC, SCC, keratoacanthoma, or malignant melanoma may infrequently occur within or adjacent to the lesion. This is called the “collision theory,” and it is seen when two different neoplasia occur in the same area, separate from each other.
Interactions of Charged Particles with Matter
Published in W. P. M. Mayles, A. E. Nahum, J.-C. Rosenwald, Handbook of Radiotherapy Physics, 2021
Using classical (non-relativistic) collision theory, Bohr showed that, combining Newton's second law (i.e. the change in momentum is equal to the impulse [the time integral of the force]) and the Coulomb law for the force between charged particles, the energy transfer Q is given by:
Dissolution of Silver Nanoparticles
Published in Huiliang Cao, Silver Nanoparticles for Antibacterial Devices, 2017
Erchao Meng, Qingbo Zhang, Feng Li, Tanya S. Peretyazhko
Zhang et al. (2011) applied hard sphere collision theory to describe kinetics of Ag nanoparticle dissolution in aqueous environments. The theory approximated molecules and atoms as hard spheres and chemical reaction as a collision between the hard spheres. Dissolution kinetics was described by the first order (Equation 6.4), and experimental and fitting results are shown in Figure 6.2. Modelling revealed that dissolution depended on the nanoparticle size and increased with the decrease in size (Figure 6.2).
Manganese-containing polydopamine nanoparticles as theranostic agents for magnetic resonance imaging and photothermal/chemodynamic combined ferroptosis therapy treating gastric cancer
Published in Drug Delivery, 2022
Zhian Chen, Zhenhao Li, Chuangji Li, Huilin Huang, Yingxin Ren, Zhenyuan Li, Yanfeng Hu, Weihong Guo
Although the CDT promotes ferroptosis and has a considerable anti-tumor effect, it is still far from satisfactory. In recent years, studies have demonstrated that the combination of CDT and PTT has improved anti-tumor effect with broad prospects (Jia et al., 2020; Jiang et al., 2021). According to the classical thermodynamic molecular collision theory, the catalytic efficiency of the Fenton reaction is temperature-regulated, thus increasing the temperature may enhance the efficiency of the Fenton reaction. Min et al. (2020) developed a graphene oxide-based iron sponge exhibiting enhanced anti-tumor effects through PTT and Fenton chemistry. The graphene oxide-based DDS previously developed by our team produces excessive ROS after near-infrared (NIR) radiation and induces significant anti-tumor effects in GC through a combination of chemical/photothermal/photodynamic therapy (Guo et al., 2021).
Core/shell multicellular spheroids on chitosan as in vitro 3D coculture tumor models
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Ching-Wen Tsai, Jyh-Horng Wang, Tai-Horng Young
Considering the collision theory, the cell distribution of spheroids in the medium is determined by the cell collision rate and the significant adhesion among cells. The former can be controlled by the cell ratio and the latter is dependent on the intercellular binding ability. In this study, the change in cell ratio, without manipulating the interaction between cells, would not modify the spheroid structure (Figure 4(C)). More importantly, the cell distribution of core/shell structure was not seeding order dependent (Figure 4(A,B)). These results indicate the formation of cell aggregates was not controlled by cell–cell collision as they could not adhere efficiently during cell collision. The cell distribution of core/shell spheroids was determined by the cell–cell interaction.
Locally advanced carcinosarcoma of the pancreas
Published in Baylor University Medical Center Proceedings, 2018
Sasha A. Still, Carlos R. Becerra, Stacia E. Clement-Kruzel, Keith M. Cavaness
Carcinosarcoma is best characterized by IHC staining. The origin of these mixed tumors has been controversial. Three histogenic theories have been proposed to explain the mechanism behind their development: collision, combination, and conversion.2 In the collision theory, carcinomatous and sarcomatous elements arise independently, whereas the combination theory suggests that both cellular components develop from a single progenitor cell. In the conversion theory, the mesenchymal (sarcomatous) component evolves from its epithelial (carcinomatous) counterparts. Current literature supports the conversion theory as the developmental basis of carcinosarcoma tumors, because most cases appear to represent cancers of monoclonal epithelial origin.2