Comparative Effect of Bunium persicum and Rosmarinus officinalis Essential Oils and Their Synergy with Citric Acid on the Oxidation of Virgin Olive Oil

The objective of this study was to evaluate the effect of Bunium persicum and Rosmarinus officinalis essential oils on the oxidation of virgin olive oil during accelerated storage. The synergistic effect between citric acid and antioxidants of natural and synthetic types was investigated. The B. persicum and R. officinalis essential oils significantly retarded the oxidation of virgin olive oil. Their antioxidant capacity was comparable to butylatedhydroxytoluene and better than β-carotene. Here we show that when natural and synthetic antioxidants are combined with citric acid, they produce an extra antioxidant effect, hence the manifestation of synergy. Generally, the essential oils of B. persicum and R. officinalis can be applied to increase the oxidative stability of virgin olive oil.     

Bionanocomposites based on alginate and chitosan/layered double hydroxide with ciprofloxacin drug: Investigation of structure and controlled release properties

In this research work, the antibiotic drug Ciprofloxacin (CFX) was intercalated into interlayer space of Zn/Al layered double hydroxides (LDH) by coprecipitation method and CFX‐LDH nanohybride was obtained. Then, the Alginate/LDH and Chitosan/LDH bionanocomposites were prepared by coating of CFX‐LDH nanohybride with Alginate and Chitosan. The LDH‐CFX nanohybride and the bionanocomposites were characterized using the powder X‐ray diffraction, the scanning electron microscope, the thermogravimetric analyses, and the Fourier transform infrared spectroscopy. In vitro release behavior of the CFX from LDH and bionanocomposites is observed in buffer solution under pH conditions (pH = 1.2, 6.8, 7.4) which have been chosen from a model of the passage materials through the gastrointestinal tract. POLYM. COMPOS., 36:1819–1825, 2015. © 2014 Society of Plastics Engineers.     

Growth and pigment production of Synechocystis sp. PCC 6803 under shear stress

Cyanobacteria, such as Synechocystis, have recently become attractive hosts for sustainable production of biofuels and bio-fixation of CO₂ due to their genetic tractability and relatively fast growth. Cultivation of cyanobacteria requires shear stress, which is generated by mixing and air bubbling. In the present work, the impact of shear stress caused by stirring and air bubbling on the growth and pigment production of Synechocystis sp. PCC 6803 is investigated. For this purpose, agitated and airlift bubble column photobioreactors were used. The results showed that the growth and yield production were improved by mixing the culture system. However, there is a limit to this improvement: In the case of air bubbling, increasing shear stress (by rising air bubbling flow rate) to more than 185 mPa did not show any significant growth enhancement, while increasing the shear stress from 40 to 185 mPa improved the yield production up to 85%. At the optimal stirring rate, the yield production in the stirred photobioreactors increased by about 60% as compared to that of unstirred culture. The measurements of chlorophyll_a and carotenoid showed a strong correlation between biomass production and total pigment content. The highest level of cellular pigment (pigment per cell) was detected at the early stages of culture growth when cells were preparing for the rapid exponential growth phase.     

Optimization of the Length of Silicon Nanowires Prepared from MACE Method Using Gene Expression Programming and Genetic Algorithm

Silicon - Metal-assisted chemical etching (MACE) of silicon is used in this study to fabricate silicon nanowire arrays (SiNWs) of different length. This method was modeled using gene expression...     

Selecting the Appropriate Carbon Source in the Synthesis of SiC Nano-Powders Using an Optimized Fuzzy Model

Silicon - In this study, different sources of carbon in the synthesis of silicon carbide were evaluated using a multi-attribute group decision-making fuzzy model including IF-MAGDM method. In this...     

Synthesis,Characterization, and Properties of Sulfonated CNT-Doped Poly(aniline-co-carbazole)-PVA Conductive Films

Conductive flexible films are successfully synthesized from polyvinyl alcohol matrix and poly(aniline-co-carbazole) charge carrier. To improve the mechanical properties of polyvinyl alcohol and promote charge transition in the conductive copolymer, dual purpose sulfonated multiwall carbon nanotube is added. Conductivity is enhanced via sulfonic acid protonic dopant and mechanical property is increased by its hexagonal nanorods. Nanocomposites are prepared by adding 0.025, 0.050, and 0.075 g of carbon nanotube which is added at 1%, 3%, and 5% loads to the polymer matrix. Films are characterized by infrared, UV–vis, X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. Conductivity is measured by the four-probe technique and mechanical property is assessed through tensile tests and dynamic mechanic thermal analysis. A 5 × 10⁻⁶ S cm⁻¹ conductivity and 116 MPa tensile strength are recorded for the conductive film with optimum dopant/nanocomposite loads. The electrochemical property and corrosion resistance are studied by cyclic voltammetry and Tafel curves, respectively. The conductive films show an increase in corrosion potential and a decrease in corrosion current referring to a reliable corrosion protection film. The water uptake and contact angle of the films are measured to be 157% and 80.1° respectively to confirm its required hydrophilic property.