Prediction of Pressure Drop of Al2O3-Water Nanofluid in Flat Tubes Using CFD and Artificial Neural Networks

In the present study, Computational Fluid Dynamics (CFD) techniques and Artificial Neural Networks (ANN) are used to predict the pressure drop value (Δp ) of Al2O3-water nanofluid in flat tubes. Δp  is predicted taking into account five input variables: tube flattening (H), inlet volumetric flow rate (Qi  ), wall heat flux (qnw  ), nanoparticle volume fraction (Φ) and nanoparticle diameter (dp ). The required output data for training the ANN are taken from the results of numerical simulations. The numerical simulations of nanofluid are performed using two phase mixture model by FORTRAN programming language. The flow regime and the wall boundary conditions are assumed to be laminar and constant heat flux respectively. The ANN results are compared with the numerical simulated one and excellent agreement is observed. To view the accuracy of ANN model, statistical measures R2 , RMSE and MAPE are used and it is seen that the ANN model has high accuracy in predicting the (Δp ) values

Three-dimensional co-culture of human spermatogonial stem cells with Sertoli cells in soft agar culture system supplemented by growth factors and Laminin

Application of a three-dimensional (3D) culture system for in vitro proliferation and differentiation of human spermatogonial stem cells (SSCs) is a useful tool for the investigation of the spermatogenesis process and the management of male infertility particularly in prepubertal cancer patients. The main purpose of this study was to investigate the proliferation of human SSCs co-cultured with Sertoli cells in soft agar culture system (SACS) supplemented by Laminin and growth factors. Testicular cells were isolated from testes of brain-dead patients and cultured in two-dimensional (2D) culture system for 3 weeks. After 3 weeks, functional SSCs were evaluated by xenotransplantation and also identification of cells was assessed by immunocytochemistry, flow cytometry, and RT-PCR. Then, SSCs and Sertoli cells were transferred to the upper layer of SACS for 3 weeks. After 3 weeks, the number of colonies and the expression of specific SSCs and Sertoli cell markers, as well as apoptotic genes were evaluated. Our results showed that transplanted SSCs, migrated into the basement membrane of seminiferous tubules of recipient mice. The expression of PLZF, α6-Integrin, and Vimentin proteins in SSCs and Sertoli cells were observed in 2D and 3D culture systems. The expression rate of PLZF, α6-Integrin, Bcl2, and colony number in SACS supplemented by Laminin and growth factors group were significantly higher than non-supplemented groups (P � 0.01), but the expression rate of c-kit and Bax in supplemented group were significantly lower than non-supplemented groups (P � 0.05). This 3D co-culture system decreased apoptosis and increased propagation of human SSCs. Therefore, this designed system can be utilized to increase the proliferation of human SSCs in prepubertal male cancer and azoospermic men to obtain an adequate SSCs number to outotransplant success and in vitro spermatogenesis. © 202

Three-dimensional co-culture of human spermatogonial stem cells with Sertoli cells in soft agar culture system supplemented by growth factors and Laminin

Application of a three-dimensional (3D) culture system for in vitro proliferation and differentiation of human spermatogonial stem cells (SSCs) is a useful tool for the investigation of the spermatogenesis process and the management of male infertility particularly in prepubertal cancer patients. The main purpose of this study was to investigate the proliferation of human SSCs co-cultured with Sertoli cells in soft agar culture system (SACS) supplemented by Laminin and growth factors. Testicular cells were isolated from testes of brain-dead patients and cultured in two-dimensional (2D) culture system for 3 weeks. After 3 weeks, functional SSCs were evaluated by xenotransplantation and also identification of cells was assessed by immunocytochemistry, flow cytometry, and RT-PCR. Then, SSCs and Sertoli cells were transferred to the upper layer of SACS for 3 weeks. After 3 weeks, the number of colonies and the expression of specific SSCs and Sertoli cell markers, as well as apoptotic genes were evaluated. Our results showed that transplanted SSCs, migrated into the basement membrane of seminiferous tubules of recipient mice. The expression of PLZF, α6-Integrin, and Vimentin proteins in SSCs and Sertoli cells were observed in 2D and 3D culture systems. The expression rate of PLZF, α6-Integrin, Bcl2, and colony number in SACS supplemented by Laminin and growth factors group were significantly higher than non-supplemented groups (P � 0.01), but the expression rate of c-kit and Bax in supplemented group were significantly lower than non-supplemented groups (P � 0.05). This 3D co-culture system decreased apoptosis and increased propagation of human SSCs. Therefore, this designed system can be utilized to increase the proliferation of human SSCs in prepubertal male cancer and azoospermic men to obtain an adequate SSCs number to outotransplant success and in vitro spermatogenesis. © 202