Browsing by Author "Mostafa, Loghman"

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Citation Count: 0
Epoxy/phenolic nanocomposite based adhesives: Non-isothermal cure kinetic study
(Elsevier, 2024) Deriszadeh, Abbas; Shahraki, Farhad; Mostafa, Loghman; Ali, Ali B. M.; Mohebbi-Kalhori, Davod; Salahshour, Soheil; Alizad, A.
The curing behavior of an epoxy/phenolic-based system containing graphene oxide (GO), and rubber powder as a toughening agent has been studied using differential scanning calorimetry (DSC) under non-isothermal conditions at a temperature from 0 to 200 degrees C. So, to better dispersion of GO nanoplates in the resin media, the surface of the GOs was modified by 1,12-diaminododecane and subsequently aforementioned reaction was confirmed by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric techniques (TGA). DSC results show that rubber powders despite toughening properties prohibited resin-curing reactions. On the other hand, modified GO led to the promotion of curing reactions. The results of differential and integral isoconversional approaches indicated low activation energy for nanocomposite containing modified GO. Furthermore, thermal stability results reveal that the maximum decomposition temperature and char yield values of samples were increased gradually by the addition of GO and rubber powder to the system.
Citation Count: 0
Investigating the effect of constant heat flux on the adsorption of doxorubicin by bio-MOF-11 biocarrier using molecular dynamics simulation
(Pergamon-elsevier Science Ltd, 2024) Liu, Zhiming; Salahshour, Soheıl; Mostafa, Loghman; Jasim, Dheyaa J.; Hammoodi, Karrar A.; Salahshour, Soheil; Sabetvand, Rozbeh
This study aimed to investigate the effect of constant heat flux on the adsorption of doxorubicin by bio-MOF-11 biocarrier using molecular dynamics simulation. The research explores the behavior of drug molecule and carrier under different thermal conditions to understand the underlying mechanisms of adsorption. The modeled samples were made of bio-MOF-11 structure, trisodium phosphate buffer (as a drug), and aqueous environment in the presence of NaCl. Technically, the atomic interaction among various atoms inside a computational box was described using a Universal Force Field. The findings of this study could contribute to the development of more effective drug delivery systems and advance the understanding of the adsorption process in carriers. The present outputs predicted the external heat flux was an important parameter in the atomic evolution of the drug-MOF system. The 0.3 W/m2 value of heat flux was optimum for drug diffusion into the MOF sample. Numerically, the number of diffused drug particles and diffusion coefficient converged to 335 and 73.19 nm2/ns (respectively) in the optimum value of heat flux. So, it was concluded that heat flux implementation to the drug-MOF system and changing this external parameter manipulated the drug adsorption (drug delivery) procedure in the designed system for various clinical applications.
Citation Count: 0
Investigating the effect of pH on the swelling process, mechanical and thermal attributes of polyacrylamide hydrogel structure: A molecular dynamics study
(Elsevier, 2024) Liu, Zhiming; Salahshour, Soheıl; Mostafa, Loghman; Jasim, Dheyaa J.; Al-Rubaye, Ameer H.; Salahshour, Soheil; Esmaeili, Shadi
Stimuli-responsive hydrogels are a class of hydrogels that undergo reversible changes in their physical or chemical properties in response to specific external stimuli. The pH is a critical environmental stimulus for stimuli-responsive hydrogels. When the pH of the surrounding environment changes, it can lead to significant alterations in the properties of the hydrogel, such as swelling behavior, mechanical strength, etc. So, understanding how pH affects the swelling behavior and mechanical properties of these hydrogels is crucial to optimize their performance in biomedical applications. Therefore, in the present study, the effect of pH on the swelling process, mechanical and thermal attributes of polyacrylamide hydrogel structure were studied using molecular dynamics simulation and LAMMPS software. The results reveal that as the pH increased from 2 to 11, the structural volume increased from 342,583 to & Aring;3. The increase in the volume of the structure was in terms of the increase in atomic fluctuations by increasing the pH, and consequently, it led to more swelling. The mechanical properties show that the ultimate strength and Young's modulus of the sample increase from 0.0298 to 0.0007 to 0.0359 and 0.0012 MPa, respectively. The reason for the increase in these parameters was that by increasing the pH, the attraction force among different components of the PAM hydrogel structure increased. This issue led to an increase in the stability of the nanostructure. Finally, the thermal properties showed that thermal conductivity increased from 0.51 to 0.62 W/m K by increasing pH to 11. The findings may lead to the development of pH-responsive hydrogels with enhanced properties, offering more effective and tailored solutions for biomedical applications.