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Among the pharmacological agents employed in cancer therapy, doxorubicin holds a prominent place due to its widespread use and potent cytotoxic effects and doxorubicin offers considerable promise in combating cancer, its administration requires careful consideration of the delicate balance between therapeutic benefit and potential harm, highlighting the intricate landscape of cancer treatment. Molecular dynamics simulation was used in this research to evaluate the effect of pH on the transfer and release kinetics of doxorubicin via carbon nanotubes within the capillary network surrounding cancer tumors. Upon examination of the acquired data, it became evident that following a duration of 10 ns, the temperature of the scrutinized structure stabilized at 310 K. Additionally, the analysis revealed that over the same period, the potential energy of examined structure reached a convergence point of 5.68 kcal/mol. Moreover, as the pH level increased from 3 to 11, a notable reduction in the maximum velocity of particle motion was detected, diminishing from 0.0028 to 0.0021 Å/fs. This elevation in pH led to a decline in the interaction between the vessel and solute, decreasing from 0.57 to 0.42 kcal/mol. Similarly, the interaction between the vessel and tumor experienced a decline, escalating from 6.95 to 6.05 kcal/mol with the pH increased from 3 to 11. Lastly, the pH elevation resulted in a marked reduction in the rate of drug release, decreasing from 84 to 46 %. This work concluded that MD simulations greatly enhanced the progress of pH-responsive CNT-based drug delivery systems. By offering comprehensive understanding of their behavior in acidic tumor environments, these simulations optimized these systems for targeted cancer treatment.

In this research, the changes of wall shear stress (WSS) of flow blood affected by stenosis and grafted vessels are studied. For the simulation of non-Newtonian fluid, blood in this paper, the Carreau fluid model is used. The severity of the stenosis is considered to reduce the internal cross-sectional area of the host vessel by 30 %. In this paper, simulations are performed on the human body in sports, which are classified into anemia (LHD), normal (NHD) and high blood pressure (HHD). Results are presented in three sections including after stenosis region, transplantation section, and after transplantation region by calculating wall shear stress (WSS). It is reported that wall shear stress is increased after stenosis location due to immediate variation in the cross-section area when blood flows. To explain, Stenosis reduces the cross-section area of the vessel which causes flow contraction. Consequently, this phenomenon increases flow velocity in the central region of blood flow whereas, after passing from stenosis, blood flow is exposed to an abrupt expansion which causes flow back from the central region to wall vicinity in lateral regions of the vessel. Maximum amounts of wall shear stress are achieved at 280 Pa, 350 Pa, and 550 Pa for anemia, normal, and hypertensive individuals in order. However, the consequence of the mentioned phenomenon in hypertensive individuals is more severe than that of anemic ones. Therefore, the geometry of veins is very important in medical surgeries to prevent vessel failure, especially in stressful points of transplantation.