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  The use of productive microorganisms in the production of primary and secondary metabolites is part of the knowledge of microbial biotechnology, which is carried out with the aim of using huge cellular factories and considering their inherent and latent ability to produce products. Investigating and optimizing the factors affecting the synthesis of metabolites will increase the growth of the strain and the yield of the product. In this regard, in this research, by using the response surface method (RSM) and Box-Behnken design, the fermentation production of cephalosporin C by Acromonium chrysogenum PTCC 5271, and the effect of three factors on the fermentation process, including pH of Fermentation culture media, rice bran and magnetite iron oxide nanoparticles have been measured at three levels. The obtained results showed that changes in the concentration of magnetite iron oxide nanoparticles and rice bran in the fermentation media significantly affect the amount of antibiotics produced. The highest amount of Cephalosporin C produced (224 mg/l) was obtained in the culture containing 0.04 mg/l magnetite iron oxide nanoparticles, 2.5 g/l rice bran and pH of 6.5. The optimized values ​​for the factors were calculated as 0.0325 mg/l, 2.6162 g/l, and 6.4545 respectively by the Mini Tab program, and finally the mathematical model for the response variable was obtained. Based on the results of this research, magnetite iron oxide nanoparticles and rice bran are suitable substrates in fermentation culture media and biological processes.

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In this research, the dynamic behavior and nonlinear vibration of a clamped-clamped initially curved microbeam under electrostatic step actuation is investigated. The initially curved microbeams under transverse loading may exhibit two different stable states and this is the basis of the emergence of bi-stable micro electro mechanical systems (MEMS). The equation of motion is derived based on energy method and Hamiltonian principle, and re-written in non-dimensional form by using appropriate non-dimensional parameters. The resultant equation of motion in non-dimensional form is discretized and converts to a system of nonlinear ordinary differential equations by using a reduced order model based on the Galerkin procedure. Runge-kutta method of order four is employed to solve the resulting system of nonlinear ordinary differential equations. COMSOL Multiphysics software is used for finite element simulation. Then, the effect of various parameters including voltage parameter, damping, initial midpoint elevation and gap length is investigated. It is concluded that the critical voltage of pull-in is decreased by increasing of the initial midpoint elevation. Also The results depict that by increasing of the damping parameter, the possibility of transition between two stable stats is eliminated.

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Strawberry (Fragaria × ananassa) is a plant belonging to the rose family, one of the most important small fruits, which is one of the most popular and widely used berries in the world due to its sweet aroma and taste. In this study, changes in qualitative and phytochemical traits of Kamaroza and Parus strawberry cultivars during 15 days of storage at 4 °C were investigated. In order to determine the possible contamination of strawberry fruit with contaminants, the amount of heavy metals was investigated using the emission spectroscopy technique by ICP. The results of comparing the studied traits in two strawberry cultivars showed that the amount of phenol, flavonoids, flavonols, anthocyanins and carbohydrates in Camarosa cultivar was significantly higher than Parus cultivar. But in terms of fiber content, Parus cultivar had more fiber content. Based on the results of comparing the data of two strawberry cultivars, after 15 days of storage, the amount of phenol, flavonoids, flavonols, carbohydrates and antioxidant capacity showed a significant increase only in Camarosa cultivar. These studies show that in terms of nutritional value and preservation of natural compounds during storage and post-harvest conditions, the type of strawberry cultivar is a determining factor, so that Camarosa has a special advantage over Parus cultivar. Examination of heavy metal results in two strawberry fruit cultivars showed that except for the amount of zinc metal, which in both strawberry species is less than the limit accepted by the World Health Organization, the amount of other heavy metals studied was higher than the standard.

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Expansion of salt stress in cultivable fields prevents plant physiological functions and reduces crop yield. Arbuscular Mycorrhizal Fungi (AMF), as a bio-amelioration of salt stress, protects cellular osmosis via disaccharide and polysaccharide metabolism changes. In this study, three Gossypium species (i.e., G. hirsutum, G. barbadense, and G. herbaceum) colonized with Rhizophagus intraradices [with AMF and without AMF] were cultivated under saline irrigation treatments (ECe< 4 Ds m^-1= S0, 8-9= S1, and 12-13= S2) as a factorial experiment. Salinity treatments were initiated at flowering. Generally, according to physiological traits, [+AMF] colonized with G. barbadense was more tolerant in exposure to 12-13 dS m^-1 salinity, while G. hirsutum with [+AMF] was just tolerant until 8-9 dS m^-1. This is because, the highest and the least leaf area were observed in G. barbadense [+AMF] under 8-9 and 12-13 dS m^-1, respectively. In 12-13 dS m^-1, the highest root volume, root dry weight, seed weight, and fiber weight were obtained in G. barbadense [+AMF]. Moreover, the highest sugar content in root and leaves and the highest starch content of root, leaves, and seed cotyledon were observed in G. barbadense [+AMF] under 12-13 dS m^-1 treatment. Under 8-9 dS.m^-1 salinity, the highest starch, Sucrose Phosphate Synthase (SPS) and Sucrose Phosphatase (SP) enzyme activities were in roots of G. barbadense [+AMF]. The present study suggests that despite dramatic physiological alterations under high-salinity in comparison with mild-salinity, AMF and G. barbadense showed the best symbiotic performance under 12-13 dS m^-1.

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Drought alters plant metabolic processes resulting in some changes at the anatomical and morphological levels. Experiments were conducted to determine the morphologic and anatomic responses of two cultivars of tomato (Solanum lycopersicum L., cultivars CaljN3 and Superstrain B) to different irrigation regimes [100, 75, 50, and 25% of Field Capacity (FC)]. Catalase 1 (CAT1) gene expression was investigated by real-time RT-qPCR and protein interaction studies in tomatoes. Drought stress caused an increase in the number of vessels in roots and stems of both cultivars. The diameter of vascular cylinders in roots of the control plants (both cultivars) was larger. Expression of the CAT1 gene did not show any significant difference in the CaljN3 cultivar under drought conditions. However, expression of the CAT1 gene indicated a significant increase in Superstrain B cultivar at the 50 and 25% FC treatments. The gene network showed that this protein interacts with superoxide dismutase, acyl-CoA oxidase, and glutathione peroxidase. CaljN3 cultivars and showed more tolerance than Superstrain B at all levels of drought treatment. Therefore, Superstrain B is considered a susceptible cultivar under drought conditions. This suggested that the defense against oxidative stress may initiate one step before the activity of antioxidant enzymes. Thus, tomato plant tries to fight the stress factor by activating proteins, especially channels, pumps, and some cellular messengers.