Production of a Recombinant Anti-Human CD4 Single-Chain Variable- Fragment Antibody Using Phage Display Technology and Its Expression in Escherichia coli

( Babaei Arash ),( Sayyed Hamid Zarkesh Esfahani ),( Marjan Gharagozloo ) 한국미생물 · 생명공학회 2011 Journal of microbiology and biotechnology Vol.21 No.5

Single-chain variable fragment (scFv) is a fusion protein of the variable regions of the heavy (VH) and light (VL) chains of immunoglobulin, connected with a short linker peptide of 10 to about 20 amino acids. In this study, the scFv of a monoclonal antibody against the third domain of human CD4 was cloned from OKT4 hybridoma cells using the phage display technique and produced in E. coli. The expression, production, and purification of anti-CD4 scFv were tested using SDS-PAGE and Western blot, and the specificity of anti-CD4 scFv was examined using ELISA. A 31kDa recombinant anti-CD4 scFv was expressed and produced in bacteria, which was confirmed by SDS-PAGE and Western blot assays. Sequence analysis proved the ScFv structure of the construct. It was able to bind to CD4 in quality ELISA assay. The canonical structure of anti-CD4 scFv antibody was obtained using the SWISS_MODEL bioinformatics tool for comparing with the scFv general structure. To the best of our knowledge, this is the first report for generating scFv against human CD4 antigen. Engineered anti-CD4 scFv could be used in immunological studies, including fluorochrome conjugation, bispecific antibody production, bifunctional protein synthesis, and other genetic engineering manipulations. Since the binding site of our product is domain 3 (D3) of the CD4 molecule and different from the CD4 immunological main domain, including D1 and D2, further studies are needed to evaluate the anti-CD4 scFv potential for diagnostic and therapeutic applications.

Investigating Buck DC-DC Converter Operation in Different Operational Modes and Obtaining the Minimum Output Voltage Ripple Considering Filter Size

Babaei, Ebrahim,Mahmoodieh, Mir Esmaeel Seyed,Sabah, Mehran The Korean Institute of Power Electronics 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.6

This paper investigates the operational modes of buck dc-dc converters and their energy transmission methods. The operational modes of such converters are classified in two types, discontinuous conduction mode (DCM) and continuous conduction mode (CCM). In this paper, the critical inductance relation of DCM and CCM is determined. The equations of the output voltage ripple (OVR) for each mode are obtained for a specific input voltage and load resistance range. The maximum output voltage ripple (MOVR) is also obtained for each mode. The filter size is decreased and the minimum required inductance value is calculated to guarantee the minimization of the MOVR. The experimental and simulation results in PSCAD/EMTDC prove the correctness of the presented theoretical concepts.

Power System Oscillations Damping Using UPFC Based on an Improved PSO and Genetic Algorithm

Babaei, Ebrahim,Bolhasan, Amin Mokari,Sadeghi, Meisam,Khani, Saeid Journal of International Conference on Electrical 2012 Journal of international Conference on Electrical Vol.1 No.1

In this paper, optimal selection of the unified power flow controller (UPFC) damping controller parameters in order to improve the power system dynamic response and its stability based on two modified intelligent algorithms have been proposed. These algorithms are based on a modified intelligent particle swarm optimization (PSO) and continuous genetic algorithm (GA). After extraction of UPFC dynamic model, intelligent PSO and genetic algorithms are used to select the effective feedback signal of the damping controller; then, to compare the performance of the proposed UPFC controller in damping the critical modes of a single-machine infinite-bus (SMIB) power system, the simulation results are presented. The comparison shows the good performance of both presented PSO and genetic algorithms in an optimal selection of UPFC damping controller parameters and damping oscillations.

Study on the response of circular thin plate under low velocity impact

Babaei, Hashem,Mostofi, Tohid Mirzababaie,Alitavoli, Majid Techno-Press 2015 Geomechanics & engineering Vol.9 No.2

In this paper, forming of fully clamped circular plate by using low velocity impact system has been investigated. This system consists of liquid shock tube and gravity drop hammer. A series of test on mild steel and aluminum alloy plates has been done. The effect of varying both impact load and the plate material on the deflection are described. This paper also presents a simple model to prediction of mid-point deflection of circular plate by using input-output experimental data. In this way, singular value decomposition (SVD) method is used in conjunction with dimensionless number incorporated in such complex process. The results of obtained model have very good agreement with experimental data and it provides a way of studying and understanding the plastic deformation of impact loads.

Dynamic compaction of cold die Aluminum powders

Babaei, Hashem,Mostofi, Tohid Mirzababaie,Alitavoli, Majid,Namazi, Nasir,Rahmanpoor, Ali Techno-Press 2016 Geomechanics & engineering Vol.10 No.1

In this paper, process of dynamic powder compaction is investigated experimentally using impact of drop hammer and die tube. A series of test is performed using aluminum powder with different grain size. The energy of compaction of powder is determined by measuring height of hammer and the results presented in term of compact density and rupture stress. This paper also presents a mathematical modeling using experimental data and neural network. The purpose of this modeling is to display how the variations of the significant parameters changes with the compact density and rupture stress. The closed-form obtained model shows very good agreement with experimental results and it provides a way of studying and understanding the mechanics of dynamic powder compaction process. In the considered energy level (from 733 to 3580 J), the relative density is varied from 63.89% to 87.41%, 63.93% to 91.52%, 64.15% to 95.11% for powder A, B and C respectively. Also, the maximum rupture stress are obtained for different types of powder and the results shown that the rupture stress increases with increasing energy level and grain size.

Capacity Bounds in Random Wireless Networks

Babaei, Alireza,Agrawal, Prathima,Jabbari, Bijan The Korea Institute of Information and Commucation 2012 Journal of communications and networks Vol.14 No.1

We consider a receiving node, located at the origin, and a Poisson point process (PPP) that models the locations of the desired transmitter as well as the interferers. Interference is known to be non-Gaussian in this scenario. The capacity bounds for additive non-Gaussian channels depend not only on the power of interference (i.e., up to second order statistics) but also on its entropy power which is influenced by higher order statistics as well. Therefore, a complete statistical characterization of interference is required to obtain the capacity bounds. While the statistics of sum of signal and interference is known in closed form, the statistics of interference highly depends on the location of the desired transmitter. In this paper, we show that there is a tradeoff between entropy power of interference on the one hand and signal and interference power on the other hand which have conflicting effects on the channel capacity. We obtain closed form results for the cumulants of the interference, when the desired transmitter node is an arbitrary neighbor of the receiver. We show that to find the cumulants, joint statistics of distances in the PPP will be required which we obtain in closed form. Using the cumulants, we approximate the interference entropy power and obtain bounds on the capacity of the channel between an arbitrary transmitter and the receiver. Our results provide insight and shed light on the capacity of links in a Poisson network. In particular, we show that, in a Poisson network, the closest hop is not necessarily the highest capacity link.

Numerical solution of beam equation using neural networks and evolutionary optimization tools

Babaei, Mehdi,Atasoy, Arman,Hajirasouliha, Iman,Mollaei, Somayeh,Jalilkhani, Maysam Techno-Press 2022 Advances in computational design Vol.7 No.1

In this study, a new strategy is presented to transmit the fundamental elastic beam problem into the modern optimization platform and solve it by using artificial intelligence (AI) tools. As a practical example, deflection of Euler-Bernoulli beam is mathematically formulated by 2nd-order ordinary differential equations (ODEs) in accordance to the classical beam theory. This fundamental engineer problem is then transmitted from classic formulation to its artificial-intelligence presentation where the behavior of the beam is simulated by using neural networks (NNs). The supervised training strategy is employed in the developed NNs implemented in the heuristic optimization algorithms as the fitness function. Different evolutionary optimization tools such as genetic algorithm (GA) and particle swarm optimization (PSO) are used to solve this non-linear optimization problem. The step-by-step procedure of the proposed method is presented in the form of a practical flowchart. The results indicate that the proposed method of using AI toolsin solving beam ODEs can efficiently lead to accurate solutions with low computational costs, and should prove useful to solve more complex practical applications.

Optimal Topologies for Cascaded Sub-Multilevel Converters

Babaei, Ebrahim The Korean Institute of Power Electronics 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.3

The general function of a multilevel converter is to synthesize a desired output voltage from several levels of dc voltages as inputs. In order to increase the steps in the output voltage, a new topology is recommended in [1], which benefits from a series connection of sub-multilevel converters. In the procedure described in this reference, despite all the advantages, it is not possible to produce all the steps (odd and even) in the output. In addition, for producing an output voltage with a constant number of steps, there are different configurations with a different number of components. In this paper, the optimal structures for this topology are investigated for various objectives such as minimum number of switches and dc voltage sources and minimum standing voltage on the switches for producing the maximum output voltage steps. Two new algorithms for determining the dc voltage sources magnitudes have been proposed. Finally, in order to verify the theoretical issues, simulation and experimental results for a 49-level converter with a maximum output voltage of 200V are presented.

Investigating the Au-Cu thick layers Electrodeposition Rate with Pulsed Current by Optimization of the Operation Condition

Babaei, Hamid,Khosravi, Morteza,Sovizi, Mohamad Reza,Khorramie, Saeid Abedini The Korean Electrochemical Society 2020 Journal of electrochemical science and technology Vol.11 No.2

The impact of effective parameters on the electrodeposition rate optimization of Au-Cu alloy at high thicknesses on the silver substrate was investigated in the present study. After ensuring the formation of gold alloy deposits with the desired and standard percentage of gold with the cartage of 18K and other standard karats that should be observed in the manufacturing of the gold and jewelry artifacts, comparing the rate of gold-copper deposition by direct and pulsed current was done. The rate of deposition with pulse current was significantly higher than direct current. In this process, the duty cycle parameter was effectively optimized by the "one factor at a time" method to achieve maximum deposition rate. Particular parameters in this work were direct and pulse current densities, bath temperature, concentration of gold and cyanide ions in electrolyte, pH, agitation and wetting agent additive. Scanning electron microscopy (SEM) and surface chemical analysis system (EDS) were used to study the effect of deposition on the cross-sections of the formed layers. The results revealed that the Au-Cu alloy layer formed with concentrations of 6gr·L^-1 Au, 55gr·L^-1 Cu, 24 gr·L^-1 KCN and 1 ml·L^-1 Lauryl dimethyl amine oxide (LDAO) in the 0.6 mA·cm^-2 average current density and 30% duty cycle, had 0.841 ㎛·min^-1 Which was the highest deposition rate. The use of electrodeposition of pure and alloy gold thick layers as a production method can reduce the use of gold metal in the production of hallow gold artifacts, create sophisticated and unique models, and diversify production by maintaining standard karats, hardness, thickness and mechanical strength. This will not only make the process economical, it will also provide significant added value to the gold artifacts. By pulsating of currents and increasing the duty cycle means reducing the pulse off-time, and if the pulse off-time becomes too short, the electric double layer would not have sufficient growth time, and its thickness decreases. These results show the effect of pulsed current on increasing the electrodeposition rate of Au-Cu alloy confirming the previous studies on the effect of pulsed current on increasing the deposition rate of Au-Cu alloy.

Jak-TGFβ cross-talk links transient adipose tissue inflammation to beige adipogenesis

Babaei, Rohollah,Schuster, Maximilian,Meln, Irina,Lerch, Sarah,Ghandour, Rayane A.,Pisani, Didier F.,Bayindir-Buchhalter, Irem,Marx, Julia,Wu, Shuang,Schoiswohl, Gabriele,Billeter, Adrian T.,Krunic, D AAAS 2018 Science signaling Vol.11 No.527

<P>The transient activation of inflammatory networks is required for adipose tissue remodeling including the 'browning' of white fat in response to stimuli such as. 3-adrenergic receptor activation. In this process, white adipose tissue acquires thermogenic characteristics through the recruitment of so-called beige adipocytes. We investigated the downstream signaling pathways impinging on adipocyte progenitors that promote de novo formation of adipocytes. We showed that the Jak family of kinases controlled TGF beta signaling in the adipose tissue microenvironment through Stat3 and thereby adipogenic commitment, a function that was required for beige adipocyte differentiation of murine and human progenitors. Jak/Stat3 inhibited TGF beta signaling to the transcription factors Srf and Smad3 by repressing local Tgfb3 and Tgfb1 expression before the core transcriptional adipogenic cascade was activated. This pathway cross-talk was triggered in stromal cells by ATGL-dependent adipocyte lipolysis and a transient wave of IL-6 family cytokines at the onset of adipose tissue remodeling induced by beta 3-adrenergic receptor stimulation. Our results provide insight into the activation of adipocyte progenitors and are relevant for the therapeutic targeting of adipose tissue inflammatory pathways.</P>