Publications by authors named "Daryoosh Vashaee"

Angiogenesis is a crucial and challenging requirement for the regeneration and repair of damaged tissues, particularly for critical-sized ones. To address this challenge, in this study, we fabricated a cell-communicating gelatin methacryloyl (GelMA) hydrogel using core-shell silica nanoparticles conjugated with roxadustat (FG-4592) and a VEGF-mimetic aptamer (Apt02). This hydrogel promotes tube formation and prevascularization synergistically through both extracellular and intracellular pathways in human umbilical vein endothelial cells (HUVEC), with FG-4592 acting via the extracellular pathway and Apt02 via the intracellular pathway.

View Article and Find Full Text PDF

The present work investigates the interfacial and atomic layer-dependent mechanical properties, SOC-entailing phonon band structure, and comprehensive electron-topological-elastic integration of ZrTe and NiTe. The anisotropy of Young's modulus, Poisson's ratio, and shear modulus are analyzed using density functional theory with the TB-mBJ approximation. NiTe has higher mechanical property values and greater anisotropy than ZrTe.

View Article and Find Full Text PDF

Addressing a critical challenge in current tissue-engineering practices, this study aims to enhance vascularization in 3D porous scaffolds by incorporating bioceramics laden with pro-angiogenic ions. Specifically, freeze-dried gelatin-based scaffolds were infused with sol-gel-derived powders of Cu-doped akermanite (CaMgSi2O) and bredigite (CaMgSiO) at various concentrations (10, 20, and 30 wt%). The scaffolds were initially characterized for their structural integrity, biodegradability, swelling behavior, impact on physiological pH, and cytocompatibility with human umbilical vein endothelial cells (HUVECs).

View Article and Find Full Text PDF
Article Synopsis
  • This paper focuses on improving the electrical conductivity and dopant distribution of n-type doped GaSb, a semiconductor material, using techniques like AC impedance spectroscopy for detailed characterization.
  • The study identifies challenges like uneven dopant distribution and incomplete activation, proposing the use of specific alloying elements like bismuth and microwave annealing to enhance material properties and reduce issues such as diffusion.
  • The findings emphasize the complexity of achieving optimal doping in GaSb, suggesting that simple grain size reduction isn't effective and highlighting the need for innovative approaches in synthesis and optimization for better thermoelectric performance.
View Article and Find Full Text PDF

Two-dimensional (2D) topological insulators (TIs) hold great promise for future quantum information technologies. Among the 2D-TIs, the TiNI monolayer has recently been proposed as an ideal material for achieving the quantum spin Hall effect at room temperature. Theoretical predictions suggest a sizable bandgap due to the spin-orbit coupling (SOC) of the electrons at and near the Fermi level with a nontrivial  topology of the electronic states, which is robust under external strain.

View Article and Find Full Text PDF

Bismuth telluride-based alloys possess the highest efficiencies for the low-temperature-range (<500 K) applications among thermoelectric materials. Despite significant advances in the efficiency of p-type BiTe-based materials through engineering the electronic band structure by convergence of multiple bands, the ntype pair still suffers from poor efficiency due to a lower number of electron pockets near the conduction band edge than the valence band. To overcome the persistent low efficiency of n-type BiTe-based materials, we have fabricated multiphase pseudobinary BiTe-BiS compounds to take advantages of phonon scattering and energy filtering at interfaces, enhancing the efficiency of these materials.

View Article and Find Full Text PDF

In this study, we investigate the enhancement of exchange bias in core/shell/shell structures by synthesizing single inverted core/shell (Co-oxide/Co) and core/shell/shell (Co-oxide/Co/Co-oxide) nanostructures through a two-step reduction and oxidation method. We evaluate the magnetic properties of the structures and study the effect of shell thickness on the exchange bias by synthesizing various shell thicknesses of Co-oxide/Co/Co-oxide nanostructures. The extra exchange coupling formed at the shell-shell interface in the core/shell/shell structure leads to a remarkable increase in the coercivity and the strength of the exchange bias by three and four orders, respectively.

View Article and Find Full Text PDF

Bismuth telluride-based thin films have been investigated as the active material in flexible and micro thermoelectric generators (TEGs) for near room-temperature energy harvesting applications. The latter is a class of compact printed circuit board compatible devices conceptualized for operation at low-temperature gradients to generate power for wireless sensor nodes (WSNs), the fundamental units of the Internet-of-Things (IoT). CMOS and MEMS compatible micro-TEGs require thin films that can be integrated into the fabrication flow without compromising their thermoelectric properties.

View Article and Find Full Text PDF

We report the topological phase and thermoelectric properties of bialkali bismuthide compounds (Na, K)RbBi, as yet hypothetical. The topological phase transitions of these compounds under hydrostatic pressure are investigated. The calculated topological surface states andtopological index confirm the nontrivial topological phase.

View Article and Find Full Text PDF

Thermal fluctuation of local magnetization intercoupled with charge carriers and phonons offers a path to enhance thermoelectric performance. Thermopower enhancement by spin fluctuations (SF) has been observed before. However, the crucial evidence for enhancing thermoelectric-figure-of-merit (zT) by SF has not been reported until now.

View Article and Find Full Text PDF

Using first-principles calculations, we predict highly stable cubic bialkali bismuthides Cs(Na, K)Bi with several technologically important mechanical and anisotropic elastic properties. We investigate the mechanical and anisotropic elastic properties under hydrostatic tension and compression. At zero pressure, CsKBi is characterized by elastic anisotropy with maximum and minimum stiffness along the directions of [111] and [100], respectively.

View Article and Find Full Text PDF

A detailed theoretical model and experimental study are presented that formulate and prove the existence of a robust ponderomotive force (PMF) near the interfaces in a granular dielectric material under microwave radiation. The model calculations show that the net direction of the PMF is pore angle-dependent. For most of the pore angles, the net force is towards the interface creating a mass transport that fills the interfacial pores and facilitates densification.

View Article and Find Full Text PDF

The purpose of this study was to produce and characterize Hydroxyapatite/Zinc Oxide/Palladium (HA/0.05 wt% ZnO/0.1 wt% Pd) nanocomposite scaffolds and study their mechanical and antibacterial properties, biocompatibility and bioactivity.

View Article and Find Full Text PDF

Magnesium (Mg) alloys are being investigated as a biodegradable metallic biomaterial because of their mechanical property profile, which is similar to the human bone. However, implants based on Mg alloys are corroded quickly in the body before the bone fracture is fully healed. Therefore, we aimed to reduce the corrosion rate of Mg using a double protective layer.

View Article and Find Full Text PDF

Thermoelectric materials could play a crucial role in the future of wearable electronic devices. They can continuously generate electricity from body heat. For efficient operation in wearable systems, in addition to a high thermoelectric figure of merit, , the thermoelectric material must have low thermal conductivity and a high Seebeck coefficient.

View Article and Find Full Text PDF

Objective: Design of bioactive scaffolds with osteogenic capacity is a central challenge in cell-based patient-specific bone tissue engineering. Efficient and spatially uniform seeding of (stem) cells onto such constructs is vital to attain functional tissues. Herein we developed heparin functionalized collagen gels supported by 3D printed bioceramic scaffolds, as bone extracellular matrix (ECM)-mimetic matrices.

View Article and Find Full Text PDF

Nanoporous bimetallic Fe-Ag nanoparticles (NPs) were synthesized using a facile chemical reduction method and used to decorate the surface of multi-walled carbon nanotubes (MWCNTs) for hydrogen sorption and storage. The effect of TiO2 nanoparticles on the hydrogen storage properties of Fe-Ag/CNTs was further studied in detail. For this purpose, several nanocomposites of nanoporous bimetallic Fe-Ag/TiO2 nanoparticles with different amounts of bimetallic Fe-Ag NPs were prepared via a hydrothermal method.

View Article and Find Full Text PDF

Magnesium (Mg) alloys as a new group of biodegradable metal implants are being extensively investigated as a promising selection for biomaterials applications due to their apt mechanical and biological performance. However, as a foremost drawback of Mg alloys, the high degradation in body fluid prevents its clinical applications. In this work, a bioceramic composite coating is developed composed of diopside, bredigite, and fluoridated hydroxyapatite on the AZ91 Mg alloy in order to moderate the degradation rate, while improving its bioactivity, cell compatibility, and mechanical integrity.

View Article and Find Full Text PDF

Early diagnosis of diseases (before they become advanced and incurable) is essential to reduce morbidity and mortality rates. With the advent of novel technologies in clinical laboratory diagnosis, microbead-based arrays have come to be recognized as an efficient approach, that demonstrates useful advantages over traditional assay methods for multiple disease-related biomarkers. Multiplexed microbead assays provide a robust, rapid, specific, and cost-effective approach for high-throughput and simultaneous screening of many different targets.

View Article and Find Full Text PDF

In recent years, there has been growing interest in optically-encoded or tagged functionalized microbeads as a solid support platform to capture proteins or nucleotides which may serve as biomarkers of various diseases. Multiplexing technologies (suspension array or planar array) based on optically encoded microspheres have made possible the observation of relatively minor changes in biomarkers related to specific diseases. The ability to identify these changes at an early stage may allow the diagnosis of serious diseases (e.

View Article and Find Full Text PDF

High performance, low cost, and low toxicity have been the main characteristics associated with magnesium-based thermoelectric materials. Nevertheless, the high volatility of magnesium creates challenges in the synthesis of these materials. In this work, n-type MgGe is synthesized using a solid-state technique, fully characterized, and compared with MgGe fabricated through different processes.

View Article and Find Full Text PDF

Objective: A systematic characterization of hybrid scaffolds, fabricated based on combinatorial additive manufacturing technique and freeze-drying method, is presented as a new platform for osteoblastic differentiation of dental pulp cells (DPCs).

Methods: The scaffolds were consisted of a collagenous matrix embedded in a 3D-printed beta-tricalcium phosphate (β-TCP) as the mineral phase. The developed construct design was intended to achieve mechanical robustness owing to 3D-printed β-TCP scaffold, and biologically active 3D cell culture matrix pertaining to the Collagen extracellular matrix.

View Article and Find Full Text PDF

Significant amount of research efforts have been dedicated to the development of scaffolds for tissue engineering. Although at present most of the studies are focused on non-load bearing scaffolds, many scaffolds have also been investigated for hard tissue repair. In particular, metallic scaffolds are being studied for hard tissue engineering due to their suitable mechanical properties.

View Article and Find Full Text PDF

In this research, a new electrochemical biosensor was constructed for the glucose detection. Iron oxide nanoparticles (FeO) were synthesized through co-precipitation method. Polyvinyl alcohol-FeO nanocomposite was prepared by dispersing synthesized nanoparticles in the polyvinyl alcohol (PVA) solution.

View Article and Find Full Text PDF

A solvent-free microsphere sintering technique was developed to fabricate scaffolds with pore size gradient for tissue engineering applications. Poly(D,L-Lactide) microspheres were fabricated through an emulsification method where TiO nanoparticles were employed both as particulate emulsifier in the preparation procedure and as surface modification agent to improve bioactivity of the scaffolds. A fine-tunable pore size gradient was achieved with a pore volume of 30±2.

View Article and Find Full Text PDF