Fluorescence resonance energy transfer detected by scanning near-field optical microscopy

Fluorescence resonance energy transfer (FRET) between excited fluorescent donor and acceptor molecules occurs via the Förster mechanism over a range of 1–10 nm. Because of the strong (sixth power) distance dependence of the signal, FRET has been used to assess the proximity of molecules in biological systems. We used a scanning near-field optical microscope (SNOM) operated in the shared-aperture mode using uncoated glass fibre tips to detect FRET between dye molecules embedded in polyvinyl alcohol films and bound to cell surfaces. FRET was detected by selective photobleaching of donor and acceptor fluorophores. We also present preliminary results on pixel-by-pixel energy transfer efficiency measurements using SNOM.     

Oil production from catfish viscera

Oil was extracted from catfish viscera and purified (degummed, neutralized, bleached, and deodorized). The yield of catfish oil after purification was 65.7%. The major yield loss took place during the degumming process. The FA found in crude catfish visceral oil were 14∶0, 16∶0, 16∶1, 18∶0, 18∶1, 18∶2, 18∶3, 20∶0, 20∶1, 20∶2, 20∶3, 20∶4, and 22∶6, the predominant FA being 18∶1, 16∶0, 18∶2, and 18∶0. The total unsaturated FA in the purified catfish oil amounted to 67.7%. The combined n−3 FA content of the purified catfish oil was 4.6 mg/g of oil. The purified catfish oil contained 1.21 mg/g DHA. FFA, water activity, and some mineral contents decreased during purification. Bleaching removed pigments, thus resulting in oil with greater lightness and less yellowness.     

Use of an Adsorption Process for Purification of Pollock-Oil-Based Biodiesel Comprises Methyl Esters

The quality of biodiesel from crude pollock oil and the effect of a purification process on the physicochemical properties of pollock oil biodiesel were evaluated. Unpurified pollock oil (PO) was transesterified to biodiesel from pollock oil (BPO) using methyl alcohol (1:6 molar ratio) and NaOH (1 % w/w of the oil weight); and the resulting fatty acids methyl esters (FAME) were purified with 10 % (w/w) activated earth to yield purified biodiesel from pollock oil (PBPO). The samples were evaluated for yield, FAME composition, free fatty acids (FFA), peroxides value (PV), moisture, bulk density, cloud point, flash point, free and total glycerin, color, rheological properties, and minerals. BPO and PBPO were evaluated for the kinetics of lipid oxidation. The transesterification and purification processes had no effect on the FAME composition of PO. The yield of PBPO was significantly (P < 0.05) reduced after the transesterification and purification processes. Moreover, the transesterification process significantly (P < 0.05) reduced the FFA, moisture, bulk density, flash point, total glycerides, redness, viscosity, arsenic and silicon content in PO. Meanwhile, the purification process significantly (P < 0.05) reduced the PV, redness, and sulfur content of BPO. The flash point of BPO was significantly (P < 0.05) increased by the purification process from 79 to 84 °C. PO, BPO, and PBPO behaved as non-Newtonian and Newtonian fluids at 0 and 25 °C, respectively. BPO showed a lower oxidation rate and activation energy compared to those of PBPO. BPO and PBPO met the ASTM biodiesel standard D6751 for moisture, bulk density, cloud point, free and total glycerin, Na, P, and S. The study demonstrated that high viscosity crude pollock oil could be converted into low viscosity purified pollock oil biodiesel.     

A Communication Library Using Active Messages to Improve Performance of PVM

We present a communication library to improve performance of PVM. The new library introduces communication primitives based on Active Messages. We propose a hybrid scheme that includes a signal driven message notification scheme plus controlled polling. The new communication library is tested along with the normal PVM library to assess the improvement in performance.     

Standardized extract of Syzygium aqueum: a safe cosmetic ingredient

Syzygium aqueum, a species in the Myrtaceae family, commonly called the water jambu is native to Malaysia and Indonesia. It is well documented as a medicinal plant, and various parts of the tree have been used in traditional medicine, for instance as an antibiotic. In this study, we show S. aqueum leaf extracts to have a significant composition of phenolic compounds, protective activity against free radicals as well as low pro-oxidant capability. Its ethanolic extract, in particular, is characterized by its excellent radical scavenging activity of EC(50) of 133 μg mL(-1) 1,1-diphenyl-2-picryl-hydrazyl (DPPH), 65 μg mL(-1) 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) and 71 μg mL(-1) (Galvinoxyl), low pro-oxidant capabilities and a phenolic content of 585-670 mg GAE g(-1) extract. The extract also displayed other activities, deeming it an ideal cosmetic ingredient. A substantial tyrosinase inhibition activity with an IC(50) of about 60 μg mL(-1) was observed. In addition, the extract was also found to have anti-cellulite activity tested for its ability to cause 98% activation of lipolysis of adipocytes (fat cells) at a concentration of 25 μg mL(-1). In addition, the extract was not cytotoxic to Vero cell lines up to a concentration of 600 μg mL(-1). Although various parts of this plant have been used in traditional medicine, this is the first time it has been shown to have cosmeceutical properties. Therefore, the use of this extract, alone or in combination with other active principles, is of interest to the cosmetic industry.     

Embedded PZT Sensor for Monitoring Mechanical Impedance of Hydrating Cementitious Materials

An embedded PZT (Lead Zirconate Titanate)-based sensor is developed for real-time, continuous, in-situ monitoring of hydrating cementitious materials after casting. The development of a multi-layer protection for a PZT patch, which provides a physical barrier with the surrounding medium while ensuring the sensitivity of measurement is described. Electrical impedance measurements from the sensor embedded inside mortar mixtures of different compositions are shown to sensitively provide an indication of changes in the state and the mechanical impedance of the material during periods associated with setting and early strength gain. An analytical procedure is developed for extracting the mechanical impedance of the surrounding cementitious material from the electromechanical measurements of the embedded PZT sensor. Changes in the mechanical impedance of mortars through periods of setting and early strength gain obtained from the embedded PZT sensor are validated using pin penetration, isothermal calorimetry and vibration-based measurements. Kinetics of hydration reaction obtained from isothermal calorimetry and increase in the penetration resistance during the setting behavior in the material, are accurately reflected in the increase in the mechanical impedance of the surrounding mortar obtained from the embedded PZT sensor. The continued increase in the mechanical impedance of the mortar after setting, up to 28 days, correlates well with the increase in elastic modulus of material obtained from vibration-based measurements. The durability of the sensor protection scheme is verified by evaluating the performance of sensors recovered from inside the mortar after long-term embedment. The embedded PZT sensor offers the potential for monitoring the local property development in a cementitious material from within the bulk of the structure and for use in quality assessment.     

Intrinsic Kinetics of Ethanol Dehydration Over Lewis Acidic Ordered Mesoporous Silicate,Zr-KIT-6

Lewis acidic Zr-KIT-6 catalyst was tested for ethanol dehydration. Under the reaction conditions studied (T = 300–380 °C, P = 1 atm, P _ethanol = 5 % in N₂), Zr-KIT-6 materials showed high ethylene selectivity (~80 %) with stable activity (60 h). The activation energy for ethanol dehydration to ethylene, estimated from intrinsic rate constants normalized with respect to the Lewis acid sites, was approximately 79 ± 1 kJ/mol.     

Electrochemical characterization of the protective film formed by the unsymmetrical Schiff's base on the mild steel surface in acid media

The corrosion inhibition efficiency of a newly synthesized Schiff's base for the corrosion of mild steel was studied in 1.0 M HCl and 0.5 M H₂SO₄ solutions. The results of weight loss measurements, electrochemical impedance and potentiodynamic polarization measurements consistently demonstrated that the Schiff's base synthesized is a good corrosion inhibitor with an inhibitory efficiency of approximately 92% at an optimum inhibitor concentration of 600 mg/L. The inhibition in both of the corrosive media was observed to be a mixed type. The potential of zero charge (PZC) at the metal–solution interface was determined for both the inhibited and uninhibited solutions to provide the mechanism of inhibition. The inhibitor formed a film on the metal surface through chloride or sulfate bridges depending upon the medium. The temperature dependence of the corrosion rate was also studied in the temperature range from 27 to 50 °C. The value of the activation energy (E_a) calculated showed that the inhibition film formation on the metal surface occurred through chemisorption. The thermodynamic parameters such as the adsorption equilibrium constant (K_ads) and the free energy of adsorption (ΔG_ads) were calculated and discussed. Several adsorption isotherms were tested and the experimental data fit well with the Langmuir adsorption isotherm.