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Objective: CREB1 is an important downstream protein for many signaling pathways. By designing efficient siRNAs against CREB1, it may be possible to assess the role of molecules involved in signaling pathways in different cell types. In this research the efficiency of CREB1 knockdown by two different siRNAs in K562 cells has been studied. Materials and Methods: siRNAs have been designed according to the criteria suggested by Reynolds et al. K562 cells were transfected by siRNA using Lipofectamine 2000. The efficiency of CREB knockdown has been assessed by quantitative relative Real-time PCR. Results: Our results have shown that only one of the siRNAs has a high level of inhibitory effect on CREB1 gene expression. The expression of CREB1 by this siRNA was knocked-down by 87% in K562 cells. Conclusion: In this research, although two siRNAs were designed according to the Reynolds et al. criteria, only one showed an inhibitory effect. Reasons other than the aforementioned criteria may be involved in effectiveness of siRNAs.

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Abstract. Phycocyanine (PC) belongs to a group of protein receptor proteins called phycobiliprotein. All of the phycobiliprotein are multi-chain proteins made up of apoproteins. Which are covalently attached to the phyclobilins. This experimental study was carried out on strain of native Anabaena doliolum,  Isolated from soils and waters of south Iran were Masjed Soleyman area. The cyanobacteria were grown and stored in BG11 medium. Then, the amount of phycocyanin produced under different light treatment and the amount of phycocyanin extracted using different ratios of multi-buffer and at two different temperatures were evaluated. The results of this study showed that the highest growth rate is when the sample is exposed to green light for three to five days. The best amount of extraction for distilled water and at a refrigerator temperature (0^◦C) with a ratio of 3:1 biomass/solvent is equal to 0.03 ± 15 µg/ml. Also, at the environment temperature, phosphate buffer is a more suitable solvent for extracting phycocyanine at a ratio of one to two with a value of 0.05 ± 8 µg/ml. In general, it can be said that the growth rate, pigment production and optimum extraction conditions for each species are quite different, and the optimal extraction of phycocyanin  in a species is also dependent on various factors such as time, temperature, solvent and the ratio of biomass to solvent.
 

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Forming limit diagram (FLD) shows the formability of metal sheets under different loading conditions before that necking is taken place. In this paper, the application of plastic instability criterion for prediction of necking and also FLD has been investigated. Using Balart’s anisotropic yield function and plastic instability criterion in different strain ratios, limit strains have been calculated, and then the limit strains have been converted to limit stresses. To verify the analytical results, a free bulge setup with the ability of applying the axial feeding has been fabricated. Tubes have been undergone different loading paths and different plane strain conditions have been induced to obtain FLD. FLDs which have been obtained using plastic instability criterion have been compared with experimental results. The results show that swift instability criterion for tubes have the best prediction of FLD in tube hydroforming process.

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Objective: Bacillus cereus (B. cereus) is a gram-positive, spore-forming bacteria widely distributed in the environment. This bacteria is an opportunistic human pathogen that can cause diarrheal and emetic types of food poisoning. The diarrhea type of food poisoning can be caused by hemolysin BL (HBL), non-hemolytic (NHE), and cytotoxin K enterotoxins. Rice is commonly contaminated with B. cereus. The objective of this study is to detect enterotoxigenic genes of the NHE complex and assess their incidence in B. cereus isolates in rice samples from Zanjan, Iran. Methods: We randomly purchased 10 different rice samples from food stores and cultured them in PEMPA. Following biochemical testing, the bacterial colonies were identified by PCR. B. cereus isolates were checked for the NHE complex genes by specific primers using multiplex PCR. Results: Results showed that rice samples were contaminated with B. cereus. The NHE complex genes were found in 8 bacterial samples. Conclusion: B. cereus is able to tolerate high temperatures; in cooked rice the spores can undergo germination by reheating. The results of this study have shown that NHE multiplex PCR is a prompt, reliable method for the differentiation between non-enterotoxigenic and enterotoxigenic isolates of B. cereus. Despite its common dietary role, rice in Iran has rarely been investigated from a microbiological point of view. Enhancing awareness about virulence and prevalence of genes involved in food poisoning would be effective in the prevention of food poisoning.

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Incremental sheet metal forming process is considered as one of methods which able manufacturer to produce parts without dedicated die in low and rapid prototype production, and many researches have been done to improve it. Using of ultrasonic vibration is one of the modern approaches in forming processes which reduce friction and forming force. The purpose of this study is to investigate the effect of ultrasonic vibration applied to the tool in single point incremental sheet metal forming process. For this, first theory of single point incremental forming has been studied; its principle has been investigated and analytical relations have been modified then analytical relations in the case of applying ultrasonic are derived from those. To practical evaluation of applying ultrasonic to this process a set can be installed to the head of CNC milling machine is designed and manufactured. According to results of analytic compared to experimental results a reasonable approximation of forming force variation in normal single point incremental forming process and applying ultrasonic can be offered. Based on tests results forming force in applying ultrasonic compare to normal mode reduces between 33 to 63.5 percent depend on test circumstances.

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Hydro-mechanical deep drawing is an advanced process in metal forming in which high pressure fluid is used to form complicated parts. Conical parts are kind of complex parts in which there is a high possibility of thinning and rupture during the forming process due to low contact area between the punch head with the blank. In this paper, the Hydro-mechanical deep drawing of Al3003-IF Steel two-layer conical parts is studied using the experimental and numerical approaches. The effects of process parameters such as friction coefficient, arrangement of layers and thickness ratio of two-layer sheet on working zone are investigated. Allowable working zone in this process indicates the applicable range of chamber pressure and drawing ratio to achieve a part without rupture. The results show that with decreasing the friction between blank and blank holder, increasing the friction between blank and punch, increasing the thickness of high formable layer and setting IF steel layer as outer layer increase the limit drawing ratio and make the allowable working zone more extensive. Finally comparison of the results obtained from experimental investigation and numerical simulation shows a good agreement between the results.

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Nowadays, two-layer sheets have many applications in various industries due to their superlative characteristics. Characteristics such as weight and formability of two-layer sheet depend on the material and the thickness of the layers which compose the two-layer sheet. Plastic instability and occurrence of localized necking limit the forming of the sheets. Forming limit diagram is used to evaluate the formability of sheet. In this paper, a multi-objective genetic algorithm is applied to optimize the thickness ratio of layers in Al3105-St14 two-layer sheet. The optimal model minimizes the weight and maximizes the formability of two-layer sheet simultaneously. Forming limit diagram of two-layer sheet is determined by analytical model based on Marciniak and Kuckzinsky (M-K) method using Barlat and Lian non-quadratic yield criterion. Experiments are also carried out on Al3105-St14 two-layer sheet in order to examine the validity of the theoretical results. Pareto-based multi-objective optimization is used in order to make the objective function of weight per unit area minimized and the objective function of formability maximized. The Pareto front provides a set of optimal solutions. In addition, the knee point as the most satisfactory solution from Pareto-set is determined using minimum distance method.

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Incremental sheet forming is one of the novel processes which is used for rapid prototyping and manufacturing of parts with complex geometries. Forming limit of sheet metal in this process is high compared to other conventional forming processes. In this paper, warm single-point incremental forming process through uniform heating to sheet along with tool heating is studied experimentally and numerically. Formability of sheet is investigated in various process condition based on the straight groove test in experimental approach and numerical simulation using finite element method. Tool heating along with uniform heating to sheet makes tool and sheet isothermal, reduces the heat loss in deformation zone and improves the deformation process. So, attainment of high forming limit is made possible. Comparison of forming limit diagrams obtained from experimental and numerical approaches shows a good agreement between the results. Effects of temperature and feed rate on the forming limit of aluminum 1050 sheet are investigated. Results show that increasing the temperature improves the formability of sheet significantly; but, the temperature is more influential on forming limit in low feed rates. Increasing the feed rate reduces the forming limit slightly; this effect is more evident in higher temperatures.
 

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The flow forming process is widely used in the production of axisymmetric industrial parts. The advantage of the flow forming process over other manufacturing methods is the use of simple tooling, reduced forming loads due to localized deformation, and enhanced mechanical properties and surface quality of finished parts. In this research, the warm flow forming process of AA6061-O aluminum alloy has been investigated for the first time. For this purpose, laboratory equipment and samples were designed and fabricated. In this study, the effect of temperature, thickness reduction, and number of passes (number of forming steps) on dimensional accuracy (thickness variation) and mechanical properties of warm flow formed AA6061-O alloys pipes have been experimentally investigated. The experimental results show that flow forming increases the strength and decreases the ductility of the formed pipe at all process levels compared to the initial non-flow forming pipe. However, the ductility of the pipe increases and its strength and microhardness decrease by increasing the forming temperature from 20 to 300 ° C. While with increasing the percentage of thickness reduction from 20% to 60% at a constant forming temperature, the strength and micro-hardness of the warm flow-formed pipe increases and its ductility decreases.

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Incremental sheet forming is a flexible forming technology in which the sheet metal is gradually formed by the movement of tools in specified path. Due to the progressively localized deformation of the sheet and concentration of the forces on contact area of tool and sheet metal, the formability of the sheet increases compared with other common forming methods. In this study, numerical simulation of the incremental forming of AA3105-St12 two-layer sheet has been performed to calculate forming force and final thicknesses of the layers. The validity of the simulation results is evaluated by comparing them with those obtained from experiments. Numerical models for estimating the vertical force applied on the tool and the final thicknesses of the layers in terms of the process variables have been obtained using artificial neural network. Multi-objective optimization has been conducted to achieve the minimum force and the minimum thickness reduction of layers using obtained numerical models based on genetic algorithm method. Optimum thickness of the two-layer sheet and the thickness ratio the layers in different states of contact of the aluminum or the steel layers with the forming tool have been determined.