Sharif Digital Repository

The promise of cell therapy has been augmented by introducing biomaterials, where intricate scaffold shapes are fabricated to accommodate the cells within. In this review, we first discuss cell encapsulation and the promising potential of biomaterials to overcome challenges associated with cell therapy, particularly cellular function and longevity. More specifically, cell therapies in the context of autoimmune disorders, neurodegenerative diseases, and cancer are reviewed from the perspectives of preclinical findings as well as available clinical data. Next, techniques to fabricate cell-biomaterials constructs, focusing on emerging 3D bioprinting technologies, will be reviewed. 3D... 

Climate change leads to more severe floods, which needs to be modeled properly. This study uses two hydraulic models including Hydrologic Engineering Center River Analysis System (HEC-RAS) and LISFLOOD-FP to simulate floods in two basins (Kashkan and Missouri) with different topographies (mountain and plain terrain). The impacts of different parameters like input resolutions, Digital Elevation Models (DEMs), roughness coefficient, and modeling techniques on flood simulation are examined. Results indicate that the performance of the models varies based on topography, input resolutions, and modeling approach. Indeed, the 2D modeling of both models in different topography types leads to better... 

Let GS be a graph with loops obtained from a graph G of order n and loops at S⊆ V(G). In this paper, we establish a neccesary and sufficient condition on the bipartititeness of a connected graph G and the spectrum Spec (GS) and Spec (GV(G)S). We also prove that for every S⊆ V(G) , E(GS) ≥ E(G) when G is bipartite. Moreover, we provide an identification of the spectrum of complete graphs Kn and complete bipartite graphs Km,n with loops. We characterize any graphs with loops of order n whose eigenvalues are all positive or non-negative, and also any graphs with a few distinct eigenvalues. Finally, we provide some bounds related to GS. © 2023, The Author(s), under exclusive licence to Malaysian... 

One of the challenges of building complex and functional tissues and organs in tissue engineering is transporting nutrients and oxygen to the tissue. The use of oxygen-releasing materials is one solution to overcome this challenge. In this study, alginate (Alg) 4% (w/v) was used as the main material for the scaffold, and calcium peroxide (CPO) was used to release oxygen. CPO can react with water and finally release oxygen, which leads to the elimination of hypoxia and effective distribution of oxygen in the scaffold. Multiple tests, including the oxygen release profile, degradability, swelling, porosity, and SEM images, performed on the bulk of the material showed that increasing the... 

Energy communities are one of the vital puzzle pieces of future smart cities. This paper proposes a novel structure for a sustainable smart city by integrating energy communities in a multi-carrier energy network. Each energy community has a manager; the so-called Energy Community Managers (ECM), who trades energy with the upstream Multi-Carrier Network Operator (MCNO). On the other hand, MCNO participates in the upstream energy markets to satisfy the demands of energy communities by maximizing its own profit. Therefore, ECMs and MCNO should solve a bilevel optimization problem associated with some common variables at both levels such as: energy carrier price and the amount of energy carrier... 

In this paper, the experimental investigation of the performance of a concentrated hybrid photovoltaic thermal solar system is sought. Accordingly, there is a parabolic trough concentrator receiver that consists of three components: a triangular duct, photovoltaic cells covering the duct, and a three-turn PHP. The PHP cools down the photovoltaic cells efficiently and regenerates waste heat. The duct is filled with a heat transfer fluid surrounding the PHP's evaporator. The condensation section of the PHP is located outside the solar concentrator. Using a one-axis polar mechanism, the concentrator tracks the sun from east to west. The system experiment setup was fabricated and tested outdoors... 

Purpose: Environmental issues and lack of drinking water have forced researchers to find some alternatives to wastewater treatment. Because dyes are used in a variety of industrial applications such as textile and pharmaceutical, wastewater of these factories leads to several environmental problems. Using catalysis under ultraviolet-irradiation (photocatalysis) is one of the cases that is used in wastewater treatment. The purpose of this work is the photocatalytic degradation of dye (Reactive Red 198) and pharmaceutical (tetracycline) using MIL-53(Fe) and MIL-100(Fe). Design/methodology/approach: In this work, Reactive Red 198 (RR198), an anionic dye and tetracycline as a pharmaceutical are... 

Perovskite solar cell (PSC) technology experiences a remarkably rapid growth toward commercialization with certified efficiency of over 25%, along with the outstanding breakthrough in the development of SnO2. Owing to the wide bandgap, high electron mobility, chemical stability, and low photocatalytic activity, SnO2 has been the rising star to serve as electron transporting layer (ETL). More importantly, the low-temperature fabrication process (<200 °C) enables SnO2 a promising candidate for the industry, making it compatible with the plastic substrates and large-scale production, which is crucial for the flexible and scalable devices fabrication. In this review, the processing methods... 

Land subsidence associated with using natural groundwater resources for serving the growing population needs has been receiving extensive research attention in the literature over the past few decades. The water content fluctuation in the of subsurface soil layers significantly impacts the land subsidence. The key objective of this study is to predict changes in water content profiles in soil layers over a long period of time using a deep learning-based approach. A convolution neural network algorithm that is commonly used in Artificial Intelligence (AI) applications is modified in the present study for processing in-situ measurement water content profiles. The approach used in the proposed... 

Uncertainty of kidney exchange programs (KEP) is one of the main challenges that cause failure in most planned transplants to proceed to surgery. Unfortunately, this challenge usually decreases KEP performance in the real world. To face this challenge, we develop an efficient approach, consisting of scheduling methodology and recourse actions, to recover failing pairs and improve the number of successful transplants in KEPs. The developed policy can be implemented in two different schemes. The first scheme receives an optimal matching as an input and determines recourse actions and the sequence of disjoint cycles and chains for the given optimal matching. However, the second scheme does not... 

The strength evolution during the processing/cycling of the metal matrix composite through accumulative roll bonding (ARB) as a severe plastic deformation method is studied by performing a twofold model. It is shown that the strength evolution during cycling consists of two parts: monolithic-like behavior and composite-like behavior. The contribution of each behavior is obtained. The particle effectiveness is at the lowest value at the beginning of the cycling and reaches its highest during the final cycles. It is shown that there is a critical strain at which monolithic-like behavior initiates to decline. The process also shows a minimum strain at which composite-like behavior dominates. ©... 

Shallow landslides triggered by heavy rainfalls have caused casualties and economic losses to domestic infrastructures and industries worldwide. Rainfall mainly reduces the soil matric suction and the shear resistance, resulting in shallow landslides. Vegetation is an eco-friendly and cost-effective method for stabilizing slopes prone to shallow landslides. This research aims to investigate the hydrological and mechanical effects of vegetation on slope stability through a numerical study approach. Vegetated and bare slopes were subjected to a recorded climate condition and two rainfall scenarios of high intensity (HI) and low intensity (LI). Matric suction and factor of safety of vegetated... 

Titanium alloys have been used extensively as implants. However, they generally suffer from low biocompatibility as well as antibacterial activity. To date, several strategies have been proposed to address these issues. It is of practical interest to synergistically increase both cellular adhesion and antimicrobial activity in titanium-based implants. Here, Ti–6Al–4V alloys were surface-modified by Nd:YAG laser with different scanning speeds ranging from 1 to 5 mm s−1 and subsequently coated by drug-loaded polymer nanofibers for prolonged drug release. The laser-modified samples were both physically and metallurgically characterized through XRD, OM, AFM, FESEM, hardness, and wettability... 

This paper proposes a risk analysis framework for substation structures based on reliability methods. Even though several risk assessment approaches have been developed for buildings, detailed risk analysis procedures for infrastructure components have been lacking in prior studies. The proposed framework is showcased by its application to a system of interconnected structures at a power substation in Tehran. Finite element models of structures are developed and validated in accordance with previous experiments. The uncertainties in the material, mass, and geometric properties of structures are described by random variables that are input to the finite element model. An artificial ground... 

The aim of this paper is to examine the characteristics and conduct of boards in non-financial Malaysian firms, with a particular emphasis on the companies’ financial leverage, using panel data spanning from 2012 to 2018. Overall, the study reveals that the relationship between board attributes and a firm’s financial leverage is significant, but mixed. Notably, we find that extremely small or large boards are ineffective in maintaining the optimal financial leverage level that benefits all stakeholders. Our study concludes that board independence is negatively correlated with financial leverage, whereas the tenure of board members is negatively associated with financial leverage.... 

A tailings dam is normally constructed through self-consolidation with minimum compaction effort. Accordingly, special attention to the ultimate limit design in assessing the tailings dam instability condition is of primary importance. Furthermore, the existence of pore fluid chemical contaminants with high concentrations makes soil hydraulic and shear resistance properties subject to considerable changes.Therefore, this study aims to investigate the stability of a tailing dam using saturated-unsaturated flow analysis under 0.2 and 0.6 M sodium chloride solutions and pure water as a benchmark. To make the analyses as realistic as possible, recently developed solute-dependent hydraulic... 

In this paper, we investigate the processes of evaporation and accretion of primordial black holes during the radiation-dominated era and the matter-dominated era. This subject is very important since usually these two processes are considered independent of each other. In other words, previous works consider them in such a way that they do not have a direct effect on each other, and as a result, their effects on the mass of primordial black holes are calculated separately. The calculations of this paper indicate that assuming these two processes independent of each other will lead to wrong results that only give correct answers within certain limits. In fact, in general, it is a mistake to... 

This paper investigates the dynamic interactions between large-scale PV plants and nearby synchronous generators. To this end, a comprehensive model of a PV plant, including the PV arrays characteristic and their voltage controller, DC/DC converter, DC-link dynamic, DC/AC inverter controllers, and output filter, is obtained. Then, the eigenvalues of the PV plant model are calculated, and it is revealed that the PV plant has a dynamic mode in the sub-synchronous oscillations (SSOs) range. Furthermore, the modal analysis method is employed, and it is shown that the inductance of the DC/DC converter and the DC-link capacitor significantly contribute to the PV sub-synchronous mode. Also, it is... 

Magnesium oxide nanoparticles (MgO NPs) have emerged as potential materials for various biomedical applications due to their unique physicochemical properties, including biodegradability, biocompatibility, cationic capacity, high stability and redox properties. MgO NPs have become an attractive platform to combat microbes and may be a promising alternative to overcome challenges associated with eliminating microbial biofilms and antibiotic resistance. Hence, due to the increasing use of MgO NPs in biomedicine, new synthetic strategies for MgO NPs are necessary. MgO NPs synthesised using green methods are non-toxic, eco-friendly and have high stability for a wide range of biological, medical... 

This paper deals with defining the concept of agent-based time delay margin and computing its value in multi-agent systems controlled by event-triggered based controllers. The agent-based time delay margin specifying the time delay tolerance of each agent for ensuring consensus in event-triggered controlled multi-agent systems can be considered as complementary for the concept of (network) time delay margin, which has been previously introduced in some literature. In this paper, an event-triggered control method for achieving consensus in multi-agent systems with time delay is considered. It is shown that the Zeno behavior is excluded by applying this method. Then, in a multi-agent system...