Sharif Digital Repository

In the present study, a hybrid microsphere/hydrogel system, consisting of polyvinyl alcohol (PVA)/sodium alginate (SA) hydrogel incorporating PCL microspheres is introduced as a skin scaffold to accelerate wound healing. The hydrogel substrate was developed using the freeze-thawing method, and the proportion of the involved polymers in its structure was optimized based on the in-vitro assessments. The bFGF-encapsulated PCL microspheres were also fabricated utilizing the double-emulsion solvent evaporation technique. The achieved freeze-dried hybrid system was then characterized by in-vitro and in-vivo experiments. The results obtained from the optimization of the hydrogel showed that... 

Total knee replacement (TKR) surgery is one of the most successful and cost-effective procedures for treating knee injuries performed in orthopedics. However, the knee replacement revision surgery will probably be required after some years. Wear at the contact area between femoral metal component and the polyethylene inserts in TKR is recognized as one of the foremost causes of prosthesis failure and necessity of revision surgery. In the present study, focusing on the patellofemoral joint (PFJ), the wear at the contact area between the patellar and femoral components has been simulated employing the explicit finite element modeling. In this regard, common types of patellar component surface... 

Using the skin tissue engineering approach is a way to help the body to recover its lost skin in cases that the spontaneous healing process is either impossible or inadequate, such as severe wounds or burns. In the present study, chitosan/gelatin-based scaffolds containing 0.25, 0.5, 0.75, and 1% allantoin were created to improve the wounds’ healing process. EDC and NHS were used to cross-link the samples, which were further freeze-dried. Different in-vitro methods were utilized to characterize the specimens, including SEM imaging, PBS absorption and degradation tests, mechanical experiments, allantoin release profile assessment, antibacterial assay, and cell viability and adhesion tests.... 

Co-Mo/Graphene composite synthesized for the first time through the spray pyrolysis method and applied as an HDS catalyst to produce a sulfur free Naphtha feed. The major advantage of the spray pyrolysis technique was its concurrent capability of the in-situ and simultaneous Co-Mo deposition upon the graphene. The produced material was characterized through the XRD, BET-BJH, FTIR and Raman spectroscopy as well as; the NH3-TPD, TPR, TEM and FESEM techniques. The prepared catalyst showed unique properties such as; high degree of total acidity of 5.1 (vs. the usual 0.2–2.0) mmole NH3/g-cat and a relatively high surface area of 705 vs. 189 m2/g of the commercial material. Furthermore, the... 

Developing extremely efficient electrocatalysts for oxygen evolution reactions (OER) is a decisive step toward the progression of rechargeable metal-oxygen batteries, CO2 reduction, and water-splitting. Nanoporous high-entropy transition-metal sulfides (np-HETMS) represent a new generation of promising OER catalysts by virtue of their exceptional catalytic activity. However, their synthesis maintains to be a challenge by reason of the thermodynamic immiscibility of the constituting multi-principal metallic elements in the sulfide structure. Herein, for the first time, the np-HETMS ((CoFeNiMnCu)S2) nanoparticles with pyrite-phase was synthesized via a facile and easy adaptable... 

Sustainability is a key issue in developing stable and efficient catalysts for solar-catalyzed CO2 conversion. The concept of structural stabilization by quenching the Gibbs free energy, which is achieved by increasing the configurational entropy level of the system, introduced high-entropy materials. However, because alloying immiscible multimetallic atoms into a unit system is still an arduous process, the potential of high-entropy materials has not yet been fully exploited. Surprisingly, although metal sulfide photocatalysts have an enviable reputation for CO2 photoreduction (CO2-PR) owing to their optical/electronic merits and more negative redox potential than other materials, the... 

Multi-shelled configurations of mixed bimetallic oxides, which are well-known candidates for CO2 photoreduction, were prepared via the calcination of rigid spheres of the self-template glycerate-assisted metal-organic structure. However, the fabrication of highly efficient, stable constructions is still a significant challenge. The effectiveness of this strategy is restricted by the questionable stability of the structure, which collapses under harsh calcination conditions. Herein, we focused our attention on manipulating the initial solvothermal reaction, through which MnCo2O4 yolk-in-double-shell hollow spheres (YDSHS-MCO) were engineered via the formation of two sequential yolk-shells,... 

Although the physiochemical merits of g-C3N4-based photocatalysts have garnered increasing interest in the fields of energy and environmental science, insufficient layer detachment has created a gap between fundamental research and practical applications. To unlock the intrinsic potential of g-C3N4, a bio-transformation of the ZnMn2O4 ((6)ZM) gel was employed to introduce highly-ordered modulation caused by steric hindrance during melamine pyrolysis. Phytomediated (6)ZM reorganized traditional carbon nitride into crossed C3N4 (CCN) monolayers, simultaneously engineering an auspicious Z-schematic system ((6)ZM/CCN). Phytoconverted (6)ZM retained the crystalline-amorphous configuration for...