Sharif Digital Repository

Investigation and analysis of circulating tumor cells (CTCs) have been valuable resources for detecting and diagnosing cancer in its early stages. Recently, enumeration and separation of CTCs via microfluidic devices have attracted significant attention due to their low cost and easy setup. In this study, novel microfluidic devices based on size-dependent cell-sorting with a trapezoidal cross-section and elliptic spiral configurations were proposed to reach label-free, ultra-fast CTCs enrichment. Firstly, the possibility and quality of separation in the devices were evaluated via a numerical simulation. Subsequently, these devices were fabricated to investigate the effects of the altering... 

Microfluidic assembly of nanoparticles (NPs) is advantageous in various fields, such as drug delivery and synthesis of photonic crystals and catalysts. The present study uses a flow-focusing microfluidic device to encapsulate silica NPs as water-in-oil (W/O) emulsions. Hence, water-based nanofluids with silica NPs are prepared, and nanofluid droplets are generated at different capillary numbers, flow rate ratios, and nanoparticle concentrations. Although most previous studies neglect the effect of the rheology of nanofluids on droplet formation, this study reveals its significance for determining droplet formation regimes as well as the size and production rates of droplets. As the nanofluid... 

Achieving high efficiency and throughput in droplet-based mixing over a small characteristic length, such as microfluidic channels, is one of the crucial parameters in Lab-on-a-Chip (LOC) applications. One solution to achieve efficient mixing is to use active mixers in which an external power source is utilized to mix two fluids. One of these active methods is magnetic micromixers using ferrofluid. In this technique, magnetic nanoparticles are used to make one phase responsive to magnetic force, and then by applying a magnetic field, two fluid phases, one of which is magneto-responsive, will sufficiently mix. In this study, we investigated the effect of the magnetic field’s characteristics... 

In this paper a complete design of a high speed optical motion analyzer system has been described. The main core of the image processing unit has been implemented by the differential algorithm procedure. Some intelligent and conservative procedures that facilitate the search algorithm have also been proposed and implemented for the processing of human motions. Moreover, an optimized modified direct linear transformation (MDLT) method has been used to reconstruct 3D markers positions which are used for deriving kinematic characteristics of the motion. Consequently, a set of complete tests using some simple mechanical devices were conducted to verify the system outputs. Considering the system... 

Background: The use of functional knee braces for returning to sports or during demanding activities following anterior cruciate ligament rupture is common; yet despite being commonly prescribed, its mechanism of action remains unknown. Objectives: To examine the effect of functional knee braces on mean muscle activity when performing lunge exercises. Study design: Pre-/post-test (within-subject research design). Methods: A total of 10 male participants with unilateral isolated anterior cruciate ligament deficiency participated. Electromyographic activities of six muscles around the knee were recorded during lunge exercises, with and without wearing a custom functional knee brace. The lunge... 

Today, organizations try to decline academically expenses using humans and resources in addition to rising managers and operators' satisfaction. Meantime, a very important step in the process of decision is the assignment of human resources, particularly in connection with research and development (R&D) projects in which the system is highly dependent on the capabilities of human resources. In this study, we tried all the assumptions that come true in the real world, considered a model for applied R&D projects to reduce costs and increase the efficiency of projects. Therefore, an integrated multiproject scheduling and multiskill human resource assignment model under uncertainty has developed... 

This paper investigates a multi-cluster Wireless Powered Communication Network (WPCN) where user clusters cooperate with a Cluster Head (CH) and a Hybrid Access Point (HAP). Employing beamforming, the HAP supplies energy in the downlink phase, while users transmit signals to the HAP and CHs in the uplink phase. We optimize the Energy Beamforming (EB) matrix, user transmit covariance matrices, and time slot allocation to enhance both max-min and sum network throughput. To tackle the non-convexity of the optimization problems, we decompose them into two subproblems and reformulate each as convex Second Order Cone Programming (SOCP) and Quadratic Constraint Quadratic Programming (QCQP) for the... 

This paper is a counterfactual analysis investigating the consequences of the formation of a currency union for Canada and the USA: whether outputs increase and prices decrease if these countries form a currency union. We use a two-country cointegrated model to conduct the counterfactual analysis, where the conditional forecasts are generated based on the Gaussian assumption. To deal with structural breaks and model uncertainty, conditional forecasts are generated from different models/estimation windows and the model-averaging technique is used to combine the forecasts. We also examine the robustness of our results to parameter uncertainty using the wild bootstrap method. The results show...