Background: Immobilization is an approach in industry to improve stability and reusability of urease. The efficiency of this technique depends on the type of membrane and the method of stabilization. Methods: The PEI-modified egg shell membrane was used to immobilize urease by absorption and glutaraldehyde cross-linking methods. The membranes were characterized by Fourier-transform infrared sp...

One model of transformation proposed that heat shock destabilizes the cell membrane and allows for plasmid uptake. As lipid composition might also affect the stability of the cell membrane, we hypothesized that a lower growth temperature would alter membrane lipid composition so as to increase transformation efficiency after heat shock. Cells were grown at 20°C and 37°C and treated with calcium...

bordetella pertussis infects the respiratory tract of the human host and causes whooping cough in children. the nature of immunity against bordetella pertussis infection and disease is poorly understood. the aim of this study was to investigate cell mediated immunity in mice immunized with outer membrane component of cell wall, of b. pertussis. a group of mice were immunized with outer membrane...

This research investigated stability of two novel aminated polyphenylene polymers as anion exchange layers in bipolar membranes. Bipolar membrane stability was tested under operating conditions of 50 mA/cm2, and under conditions of soaking in room temperature 1 M NaOH. The stability of the custom made bipolar membranes was compared with those for two commercial membranes. For the polyphenylene-...

in this paper the role of super paramagnetic iron oxide nanoparticles (spi) on platinum nanoclusters on activated carbon (pt/c) for electrocatalytic oxygen reduction reaction was considered. four composites of pt/c and super paramagnetic iron oxide nanoparticles were prepared with the same total composites weight and different loading of pt/c (1.2, 0.6, 0.4 and 0.3 mg ). the composite attached ...

reduced graphene oxide film was synthesized on a glassy carbon electrode by electro reduction of graphene oxide powders in aqueous solution. then platinum nano particles were deposited on reduced graphene oxide film that was deposited on the glassy carbon electrode via electro reduction of platinum salt. the physical morphology of the platinum on reduced graphene oxide film was evaluated by sca...

the nafion 117 membrane was doped with sio2 particles by sol-gel reaction. the reaction conditions to minimize leaching were investigated by using full factorial design of experiment. the results from the full factorial analysis indicated that the lowest amount of leaching takes place at 60oc without addition of acid and swelling of membranes prior to the reaction. the membranes, prepared at op...

the electrocatalysis of the oxygen reduction reaction (orr) on carbon supportedpt-v (1:1) catalyst in polymer electrolyte fuel cells (pefc) was investigated. atan oxygen pressure of one atm an enhanced electrocatalytic property of pt-v/ccompared with pt/c is revealed. these results indicate the occurrence of adifferent electrocatalytic mechanism for the orr on pt/c and pt-v/c. anincrease of mas...

Signaling molecules play an important role for many cellular functions. We investigate here a general system of two membrane reaction–diffusion equations coupled to a diffusion equation inside the cell by a Robin-type boundary condition and a flux term in the membrane equations. A specific model of this form was recently proposed by the authors for the GTPase cycle in cells. We investigate here...