Crocin loaded nano-emulsions: Factors affecting emulsion properties in spontaneous emulsification

Spontaneous emulsification may be used for encapsulating bioactive compounds in food and pharmaceutical industry. It has several advantages over high energy and other low energy methods including, protecting sensitive compounds against severe conditions of high energy method and its ability to minimize surfactant, removal of cosurfactant and thermal stability compared with other low energy methods. In this study, we examined possibility of encapsulating highly soluble crocin in W/O micro-emulsions using spontaneous method which further could be used for making double emulsions. Nonionic surfactants of Span 80 and polyglycerol polyricinoleate (PGPR) were used for making micro-emulsions that showed the high potential of PGPR for spontaneous method. Surfactant to water ratio (SWR) was evaluated to find the highest amount of aqueous phase which can be dispersed in organic phase. Droplet size decreased by increasing SWR toward the SWR = 100 which had the smallest droplet size and then increased at higher levels of surfactant. By increasing SWR, shear viscosity increased which showed the high effect of PGPR on rheological properties. This study shows in addition to W/O micro-emulsions, spontaneous method could be used for preparing stable O/W micro-emulsions. © 2015 Elsevier B.V

Rheological modelling of viscoelastic fluid in a generic gap of screw pump

In this study, the leakage of a non-Newtonian fluid, i.e. silicone oil, in a generic gap was numerically investigated. A CFD tool is used to determine the relationship between leakage flow, gap length and pressure difference. The investigated fluid is viscoelastic and its properties are modelled by a Maxwell equation. The Maxwell model can be used to precisely define the phenomenon of stress relaxation. Moreover, a comparison of the viscosity of measured data with simplified models shows that the Maxwell model is best suited for viscosity prediction. Furthermore, simulation results showed that at low pressures, leakage is reduced by decreasing the gap angle. However, this effect changes with increasing viscosity and relaxation time of the molecule. To determine the pressure drop, the Bagley plot is used. The results confirmed that as the shear rate increases, the elastic pressure drop values increase. In addition, the leakage flow increases with an increasing slenderness ratio

ORS1, an H(2)O(2)-Responsive NAC Transcription Factor, Controls Senescence in Arabidopsis thaliana

We report here that ORS1, a previously uncharacterized member of the NAC transcription factor family, controls leaf senescence in Arabidopsis thaliana. Overexpression of ORS1 accelerates senescence in transgenic plants, whereas its inhibition delays it. Genes acting downstream of ORS1 were identified by global expression analysis using transgenic plants producing dexamethasone-inducible ORS1-GR fusion protein. Of the 42 up-regulated genes, 30 (similar to 70%) were previously shown to be up-regulated during age-dependent senescence. We also observed that 32 (similar to 76%) of the ORS1-dependent genes were induced by long-term (4 d), but not short-term (6 h) salinity stress (150 mM NaCl). Furthermore, expression of 16 and 24 genes, respectively, was induced after 1 and 5 h of treatment with hydrogen peroxide (H(2)O(2)), a reactive oxygen species known to accumulate during salinity stress. ORS1 itself was found to be rapidly and strongly induced by H(2)O(2) treatment in both leaves and roots. Using in vitro binding site selection, we determined the preferred binding motif of ORS1 and found it to be present in half of the ORS1-dependent genes. ORS1 is a paralog of ORE1/ANAC092/AtNAC2, a previously reported regulator of leaf senescence. Phylogenetic footprinting revealed evolutionary conservation of the ORS1 and ORE1 promoter sequences in different Brassicaceae species, indicating strong positive selection acting on both genes. We conclude that ORS1, similarly to ORE1, triggers expression of senescence-associated genes through a regulatory network that may involve cross-talk with salt- and H(2)O(2)-dependent signaling pathways

Classical tests in brane gravity

The vacuum solutions in brane gravity differ from those in 4D by a number of additional terms and reduce to the familiar Schwarzschild metric at small distances. We study the possible roles that such terms may play in the precession of planetary orbits, bending of light, radar retardation and the anomaly in mean motion of test bodies. Using the available data from Solar System experiments, we determine the range of the free parameters associated with the linear term in the metric. The best results come from the anomalies in the mean motion of planets. Such studies should shed some light on the origin of dark energy via the solar system tests.Comment: 10 pages, no figures, to appear in CQ

Comparative study of biosurfactant producing bacteria in MEOR applications

In this work, biosurfactant production by Bacillus subtilis, Pseudomonas aeruginosa, and Bacillus cereus has been compared. These microorganisms were isolated from agricultural and oil polluted area of Iran. Maximum biosurfactant production reached to about 1.6 g/l and liquid surface tension decreased from 72 to 25 mN/m using B. subtilis. All screened bacteria exhibited a good ability to emulsify the crude oil. Biosurfactant of B. subtilis attained an emulsion index of 75% for crude oil which was significantly greater than other strains. Stability studies were carried out under the extreme environmental conditions as find normally in the oil reservoir such as high temperature, pH and salinity. Results showed an excellent resistance of all produced biosurfactants to retain their surface-active properties at extreme conditions. It was found that the biosurfactants show a good stability around pH of 4 but at lower pH, they will harmfully be affected. Lesser precipitation has been observed at low pH for biosurfactant produced by B. subtilis. It has also been observed that biosurfactants from three isolated bacteria were able to support the condition up to 25 g/l salinity. B. cereus biosurfactant was even stable at the higher salinity. Regarding temperature, all produced biosurfactants demonstrated a good stability in the temperature up to 120 °C. Oil displacement experiments in micromodel with kerosene showed around 25% recovery of residual oil after water flooding when the biosurfactant of B. subtilis was added. These results suggest that biosurfactants of these indigenous isolated strains are appropriate candidates for enhanced oil recovery with a preference to biosurfactant of B. subtilis.Hossein Amani, Mohammad Hossein Sarrafzadeh, Manouchehr Haghighi, Mohammad Reza Mehrni

Measurement of toxic elements in infant food supplements marketed in Iran (short comunication)

Due to similarities with breast-feeding, baby food is used as a partial replacement for babies between 6 to 12 months of age. In this study, five samples of famous infant food supplement consisting of three types from Ghoncheh company (rice with milk, wheat with milk, almond porridge) and two types from Nestle company (wheat and milk, and banana and wheat with milk) were prepared. Samples were digested with nitric acid and the concentrations of cadmium, lead, manganese, molybdenum and nickel were analyzed. In addition, the estimated daily intake (EDI) index for all samples was calculated and compared with tolerable daily intake (TDI) index. The minimum and maximum concentration of cadmium was found in the sample with rice + milk formula (40.3 µg/kg) and infant food supplements containing wheat + milk (58.0 µgr/kg), respectively. The amount of cadmium, lead, manganese, molybdenum and nickel were estimated in the range of 40.3-58.0 ppb, 31.85 ppb, 2.3-4.9 ppm, 417.9-518.8 ppb and 4479.1-6415.0 ppb, respectively. In was concluded that the amount of toxic elements in infant foods marketed in Iran were found below the maximum limit

Scale up and application of biosurfactant from bacillus subtilis in enhanced oil recovery

There is a lack of fundamental knowledge about the scale up of biosurfactant production. In order to develop suitable technology of commercialization, carrying out tests in shake flasks and bioreactors was essential. A reactor with integrated foam collector was designed for biosurfactant production using Bacillus subtilis isolated from agricultural soil. The yield of biosurfactant on biomass (Y(p/x)), biosurfactant on sucrose (Y(p/s)), and the volumetric production rate (Y) for shake flask were obtained about 0.45 g g(-1), 0.18 g g(-1), and 0.03 g l(-1) h(-1), respectively. The best condition for bioreactor was 300 rpm and 1.5 vvm, giving Y(x/s), Y(p/x), Y(p/s), and Y of 0.42 g g(-1), 0.595 g g(-1), 0.25 g g(-1), and 0.057 g l(-1) h(-1), respectively. The biosurfactant maximum production, 2.5 g l(-1), was reached in 44 h of growth, which was 28% better than the shake flask. The obtained volumetric oxygen transfer coefficient (K(L)a) values at optimum conditions in the shake flask and the bioreactor were found to be around 0.01 and 0.0117 s(-1), respectively. Comparison of K(L)a values at optimum conditions shows that biosurfactant production scaling up from shake flask to bioreactor can be done with K(L) a as scale up criterion very accurately. Nearly 8% of original oil in place was recovered using this biosurfactant after water flooding in the sand pack.Hossein Amani, Mohammad Reza Mehrnia, Mohammad Hossein Sarrafzadeh, Manouchehr Haghighi and Mohammad Reza Soud

Optimization of the Production of Biosurfactant From Iranian Indigenous Bacteria for the Reduction of Surface Tension and Enhanced Oil Recovery

The optimum conditions for biosurfactant production by Iran's isolates were examined. The Taguchi method was used to identify nutritional requirements in the medium using four parameters; that is, carbon source, nitrogen, phosphorous, and salt concentrations. The use of whey, oil, and sucrose as carbon sources; NaCl as salt source; (Na2HPO4, NaH2PO 4) as phosphorous source; and (NH4)2SO 4 as nitrogen source was examined to determine bacteria optimum conditions. According to the Taguchi method using the sucrose source, the optimal conditions for Bacillus subtilis were 50 g/L NaCl, 13.53 g/L (Na 2HPO4, NaH2PO4), and 1 g/L (NH 4)2SO4; for Bacillus cereus they were 25 g/L NaCl, 13.53 g/L (Na2HPO4, NaH2PO4), and 1 g/L (NH4)2SO4; and for Pseudomonas putida they were 25 g/L NaCl, 13.53 g/L (Na2HPO4, NaH 2PO4), and 1 g/L (NH4)2SO 4. Oil displacement experiments in the micromodel at optimum conditions showed around 25% recovery of residual oil with added supernatant of Bacillus subtilis. Copyright © Taylor & Francis Group, LLC.H. Amani, M. Haghighi, M. H. Sarrafzadeh, M. R. Mehrnia, and F. Shahmirzae