Sharif Digital Repository

Accurate and early detection of anomalies in peripheral white blood cells plays a crucial role in the evaluation of well-being in individuals and the diagnosis and prognosis of hematologic diseases. For example, some blood disorders and immune system-related diseases are diagnosed by the differential count of white blood cells, which is one of the common laboratory tests. Data is one of the most important ingredients in the development and testing of many commercial and successful automatic or semi-automatic systems. To this end, this study introduces a free access dataset of normal peripheral white blood cells called Raabin-WBC containing about 40,000 images of white blood cells and color... 

Cell separation microfluidic devices have evolved into a multitude of biomedical and clinical research. Nonetheless, many critical issues remain in the way of achieving an excellent separation of target cells from a heterogeneous sample. Parallel to the abundant experimental studies related to the hybrid microfluidic methods, it is easy to perceive the lack of numerical investigations in order to optimize the separation process and its accuracy. In this study, for the first time to the best of our knowledge, a hybrid system by integrating acoustophoresis and pinched-flow fractionation (PFF) is proposed to achieve a viable system for a wide-range, precise separation. Employing the ultrasound... 

Conducting polymer-based devices and scaffolds has become remarkably popular due to their properties such as conductivity, tunable electrochemical properties, and straightforward fabrication procedures. Hence, they have versatile applications and can be used as implants, biosensors, cell capture/release devices, and regenerative medicine scaffolds. This review addresses the effect of conductive polymers on cell behavior since their conductive features can be applied to simulate a cellular response. Moreover, the impact of polymer chemical and physical properties on cellular response has been discussed. Recent biomedical engineering approaches used for cell capture and release were reviewed... 

Caching at network edges has attracted more and more research interests recently for the purpose of alleviating the network traffic pressure especially in backhaul links and improving user experience. We study Heterogeneous Cellular Caching Networks (HCCNs) consisting of macro cells in which $N$ small cell base stations (SBSs) equipped with cache memory operate in conjunction with the macro cell base station (MBS). We provide closed-form expressions of the MBS and SBSs utilization factors and average user-experienced-delay in HCCNs with overlapping coverage regions, considering general traffic models for the request arrivals based on the Independent Reference Model (IRM) and renewal traffic... 

Porous scaffolds composed of gelatin/poly (vinyl alcohol), (Gel/PVA), were prepared using combination of freeze gelation and freeze drying methods. The effect of polymer concentration, gelatin/PVA ratio, and glutaraldehyde/gelatin ratio (GA/Gel) was investigated on morphology of pores, swelling ratio, biodegradation, and skin cell culture. At optimum preparation conditions the scaffolds had uniform pore size distributions showing high swelling ratio of 23.6. The scaffolds were of biodegradable nature and almost degraded in 28 days. Human dermal fibroblast cells (HDF) were cultured on the scaffolds and MTS assay was conducted to evaluate the influence of PVA on growth and proliferation of the... 

Bioinspired materials can mimic the stem cell environment and modulate stem cell differentiation and proliferation. In this study, biomimetic micro/nanoenvironments were fabricated by cell-imprinted substrates based on mature human keratinocyte morphological templates. The data obtained from atomic force microscopy and field emission scanning electron microscopy revealed that the keratinocyte-cell-imprinted poly(dimethylsiloxane) casting procedure could imitate the surface morphology of the plasma membrane, ranging from the nanoscale to the macroscale, which may provide the required topographical cell fingerprints to induce differentiation. Gene expression levels of the genes analyzed... 

In this paper, a two-dimensional, two-phase, non-isothermal model is presented to predict the electrochemical, mass transfer and heat transfer behaviors in a direct methanol fuel cell (DMFC). Governing equations including the momentum, continuity, heat transfer, proton and electron transport, species transport for water, methanol, and all the gas species (carbon dioxide, methanol vapor, water vapor, oxygen, and nitrogen) and the auxiliary equations are coupled to studying the various phenomena in DMFC. The modeling results agree well with the four different experimental data in an extensive range of operation conditions. A parametric study is also performed to examine the effects of the cell... 

A fast statistical method for the analysis of the Read SNM of a 6 T SRAM cell in near/subthreshold region is proposed. The method is based on the nonlinear behavior of the cell. DIBL and body effects are thoroughly considered in the derivation of an accurate closed form solution for the Read Static Noise Margin (SNM) of the near/subthreshold SRAM cell. This method uses the state space equation to derive the Read SNM of the cell as a function of threshold voltage of cell transistors. This function shows the dependency of the Read SNM on sizing, VDD, temperature, and threshold voltage variations. It provides a fast reliability analysis for a cell array of a given size and a supply voltage. It... 

This brief introduces a differential eight-transistor static random access memory (SRAM) cell for subthreshold SRAM applications. The symmetric topology offers a smaller area overhead compared with other symmetric cells for the same stability in the read operation. Two transistors isolate the cell storage nodes from the read operation path to maintain the data stability of the cell. This topology improves the data stability at the expense of read operation delay. Thorough postlayout Monte Carlo worst corner simulations in 45-nm CMOS technology are conducted. The proposed cell operates down to 0.35 V with a read noise margin of 74 mV and a write noise margin of 92 mV. Under this condition,... 

As technology scales the area constraint is becoming less restrictive, but soft error rate and leakage current are drastically increased with technology down scaling. Therefore, in nano-scaled CMOS technology, the reduction of soft error rate and leakage current is the most important challenge in designing field programmable gate arrays (FPGA). To overcome these difficulties, based on the observations that most configuration bit-streams of FPGA are zeros across different designs and that configuration memory cells are not directly involved with signal propagation delays in FPGA, this paper presents a new family of configuration memory cells for FPGAs in nano-scaled CMOS technology. When... 

Single-layer reduced graphene oxide nanoribbons (rGONRs) were obtained through an oxidative unzipping of multi-walled carbon nanotubes and a subsequent deoxygenation by hydrazine and bovine serum albumin. Human mesenchymal stem cells (hMSCs) were isolated from umbilical cord blood and used for checking the concentration- and time-dependent cyto- and geno-toxic effects of the rGONRs and reduced graphene oxide sheets (rGOSs). The cell viability assay indicated significant cytotoxic effects of 10 μg/mL rGONRs after 1 h exposure time, while the rGOSs exhibited the same cytotoxicity at concentration of 100 μg/mL after 96 h. The oxidative stress was found as the main mechanism involved in the... 

In this paper, we investigated phase synchronization in delayed dynamical networks. Non-identical spiking Hindmarsh-Rose neurons were considered as individual dynamical systems and coupled through a number of network structures such as scale-free, Erdos-Rényi, and modular. The individual neurons were coupled through excitatory chemical synapses with uniform or distributed time delays. The profile of spike phase synchrony was different when the delay was uniform across the edges as compared to the case when it was distributed, i.e., different delays for the edges. When an identical transmission delay was considered, a quasi-periodic pattern was observed in the spike phase synchrony. There... 

In this paper, we study the power allocation problem in multi-cell orthogonal frequency division multiple access (OFDMA) networks. In order to improve system performance in cell-edges, users are separated into two groups with respect to their distance from base-stations (BSs): Central users and cell-edge users. Coordinated multi-point joint transmission (CoMP-JT) technology incorporated with static clustering is used for users near the cell-edges. In addition, our goal is to serve users with different target signal to interference plus noise ratio (SINR) according to their requested quality of services. Consequently, revenue of the service provider is considered as another factor and two... 

Foamy Al alloy SiCp composites of different densities ranging from 0.4 to 0.7g/cm3 were manufactured by melt-foaming process, which consisted of direct CaCO3 addition into the molten A356 aluminum bath. Mechanical properties and morphological observations indicated that the three-stage deformation mechanism of typical cellular foams is dominant in the produced A356 aluminum foams. Middle-stage stress plateau shrinkage plus compressive strength and bending stress enhancements were observed in denser foams. With the same Al/SiCp ratio, energy absorption ability and plastic collapse strength of the closed-cell foams were increased with the foam density. Doubling cell-face bending effects... 

As transistor dimensions are reduced due to technological advances, the area constraint is becoming less restrictive, but soft error rate, leakage current, and process variation are drastically increased. Therefore, in nano-scaled CMOS technology, soft error rate, leakage current and process variation are the most important issues in designing embedded cache memory. To overcome these challenges, and based on the observation that cache-resident memory values of ordinary programs exhibit a strong bias towards zero, this paper deals with new low leakage, hardened, and read-static-noise-margin-free SRAM memory cells for nano-scaled CMOS technology. These cells are completely hardened and cannot... 

Operation of an optomechanical system for color reflection study is reported. The reported system consists of a double-fiber optical design and an electro-mechanical scanning system. In the double-fiber arrangement one fiber transmits the source light to the target surface and the second one sends the reflected light off the sample target to a photodetector. By scanning the double-fiber probe in one-direction reflection properties of different color liquid samples are investigated in this study. A cubic cell made of glass material is used as the liquid container and reflection signals are compared for different filled color liquids. The maximum reflection signals are: for the yellow color... 

In this study, neural network models have been used to predict the mechanical behaviors of mouse embryos. In addition, sensitivity analysis has been carried out to investigate the influence of the significance of input parameters on the mechanical behavior of mouse embryos. In order to reach these purposes two neural network models have been implemented. Experimental data earlier deduced-by [Flückiger, M. (2004). Cell Membrane Mechanical Modeling for Microrobotic Cell Manipulation. Diploma Thesis, ETHZ Swiss Federal Institute of Technology, Zurich, WS03/04]-were collected to obtain training and test data for the neural network. The results of these investigations show that the correlation... 

Biological cell injection is a sensitive and important work which is implemented in injection of foreign materials into individual cells. Microinjection is significantly developed in the field of drug discovery and genetics so predicting the behavior of cell in microinjection is remarkably important because a tiny excessive manipulation force can destroy the tissue of the biological cell. There are a few analytical methods available to simulate the cell injection, hence the numerical methods such as FEM are suitable to be used to model the microinjection. In this study, a new spherical super element is presented to model the biological cells and deformation of a specific cell under an... 

Biological cell injection is a sensitive and important work which is implemented in injection of foreign materials into individual cells. Microinjection is significantly developed in the field of drug discovery and genetics so predicting the behavior of cell in microinjection is remarkably important because a tiny excessive manipulation force can destroy the tissue of the biological cell. There are a few analytical methods available to simulate the cell injection, hence the numerical methods such as FEM are suitable to be used to model the microinjection. In this study, a new spherical super element is presented to model the biological cells and deformation of a specific cell under an... 

Vertically aligned multi-wall carbon nanotube (CNT) arrays were fabricated in tip-growth mode on Ni/Si substrates using plasma enhanced chemical vapor deposition. In a purification process including hydrogenation and acid washing of the Ni/CNTs, the oxygen-containing functional groups were substantially reduced and a wide hollow core at the tip of the CNTs was formed by removing the Ni seeds. Sol-gel silver nanoparticles were deposited on the surface of the unpurified Ni/CNTs, while they could also be embedded within the hollow core of the Ni-removed CNTs. The persistency of the silver ions in the Ni-removed Ag-CNTs in comparison to the release of the silver ions from the Ag-Ni/CNTs in a...