Mathematical modeling of heat transfer in tissues with skin tumor during thermotherapy.

The study of thermal therapy to tumors and the response of living cells to this therapy used to treat tumor is very important due to the complexity of heat transfer in biological tissues. In the past few years, there has been a growing interest among clinicians, mathematicians, and engineers regarding the use of computational and mathematical methods to simulate biological systems. Numerous medical proceedings also employ mathematical modeling and engineering techniques as a means to guarantee their safety and evaluate the associated risks effectively. This manuscript provides an analytical solution used for the first time to study the mechanism of biological thermal response during heat therapy on spheroidal skin tumor. The proposed method used a generalized thermoelasticity model with one relaxation time. The influence of relaxation times on the responses of diseased and healthy tissues is studied and interpreted graphically. Also, the impact of different laser irradiance on the thermal profile of the malignant tumor cells over a period of 2 minutes is interpreted graphically. To investigate the transfer of heat within biological tissues during the thermal therapy, the Laplace transform and inverse Laplace transform methods were applied. A comparison of the present generalized thermoelasticity model and different models based on Pennes bioheat transfer PBT shows that our proposed model yields more realistic and accurate predictions. The current model can be used to explain various therapeutic methods.

Dynamic response of a long cylinder under thermal shock in micropolar thermoelasticity.

In this manuscript, the dynamic response of a long cylinder subjected to an asymmetric thermal shock is investigated within the framework of generalized micropolar thermoelasticity. The displacement and micro-rotation are assumed to vanish at the surface. Laplace transformation techniques are used to solve the problem. The solution is obtained in the transformed field using an innovative direct approach. Furthermore, we obtain the inverse transformations using a numerical method based on Fourier expansion. The obtained results are carefully presented through graphical representations and discussed extensively across different relaxation time values. It is evident that the relaxation time parameter significantly influences all the distributions. The displacement distributions are always continuous, whereas all other functions, including temperature variation, stress distribution, and micro-rotation, exhibit discontinuity at the wave front. The results obtained hold significant importance in various technological applications and in the manufacturing of mechanical components.

Values of using QTc and N-terminal fragment of B-type natriuretic peptide as markers for early detection of acute antipsychotic drugs-induced cardiotoxicity.

We aimed at studying the acute cardiotoxicity of the most commonly used antipsychotics in Egypt using QTc interval and NT-proBNP as markers for the early detection of such cases. Eighty-two admitted patients, at El-Minia PCC (period from 1-7-2005 to 30-6-2010), were classified into 3 groups: I: acute thioridazine overdose (n = 28), II: acute pimozide overdose (n = 23), and III: acute clozapine overdose (n = 31). Patients were investigated for NT-proBNP level and QTc on admission (day 0) and after 24 h (day 1). All the studied drugs had the ability to induce cardiotoxicity in the form of hypotension and dysrhythmias. Thioridazine and pimozide had potentially serious cardiotoxic effects than clozapine. NT-proBNP levels were elevated significantly in all groups on days 0 and 1 when compared with the reference value and a significant decrease in the same parameter on day 1 when compared with that of day 0 within the same group. QTc showed a significant prolongation in all studied groups on days 0 and 1, and there was a significant shortening of QTc on day 1 when compared with that of day 0 within the same group. A significant positive correlation of NT-proBNP level elevation with QTc prolongation was reported in all groups on days 0 and 1. Serious dysrhythmias were associated with QTc prolongation greater than 500 ms. And it was concluded that NT-proBNP, in adjunction with QTc measurement, may be a valuable and sensitive laboratory biomarker to predict cardiotoxicity of antipsychotic overdose. Larger multicenter studies are still needed to verify this possible relationship.