(Ga<Subscript>54.59</Subscript>In<Subscript>44.66</Subscript>Er<Subscript>0.75</Subscript>)<Subscript>2</Subscript>S<Subscript>300</Subscript> single crystal: novel material for detection of γ-radiation by photoinduced nonlinear optical method

It was shown a possibility to use the (Ga_54.59In_44.66Er_0.75)₂S₃₀₀ single crystal as optoelectronics detectors of gamma-irradiation using photoinduced nonlinear optical methods and photoluminescence. The crystal was irradiated by a ⁶⁰Co source at ambient conditions. The average energy of the incident γ-rays was about 1.25 MeV. The luminescence excitation was carried out using a 150 mW cw laser with wavelength 532 nm. The best results sensitive to the gamma irradiation were obtained for the third harmonic generations (THG) of the materials treated by bicolor Er: glass laser two beams propagated at angles about 21°–24°. The photoinduced gratings profile also were explored and their correlation with the gamma radiation and nonlinear optical response were explored. Comparison of photoluminescence and photoinduced nonlinear optical sensitivity to radiations was performed.     

Phospholipid,Oleic Acid Micelles and Dietary Olive Oil Influence the Lutein Absorption and Activity of Antioxidant Enzymes in Rats

This study reports on the results of repeated gavages and dietary feeding of lutein dispersed either in phospholipids or fatty acid micelles or vegetable oils and the effects on lutein bioavailability and antioxidant enzymes in rats. For the gavage study, rats (n = 5/group) were intubated with lutein solubilized either in oleic acid (OLA, 18:1n-9) or linoleic acid (LNA, 18:2n-6) or phosphatidylcholine (PC) or lysophosphatidylcholine (LPC) or no phospholipid (NoPL) micelles for 10 days. For the dietary study, rats (n = 5/group) were fed a diet containing fenugreek leaf (lutein source), either with olive (OO) or sunflower (SFO) or groundnut (GNO, control) oil or l-α-lecithin (PL) for 4 weeks. The gavage study showed that the plasma, liver and eye lutein levels in OLA and LPC groups were higher by 23.9, 20.8 and 25.5% and 16.1, 28.5 and 14.0% than LNA and PC groups, respectively. The dietary study showed the plasma (35.0 and 43.5%) and eye (18.5 and 37.0%) lutein levels in OO were higher than SFO and GNO groups. The plasma and eye lutein levels in the PL group were higher by 20 and 31.3% than in the control. It is evident that OO and PL modulate lutein absorption, which in turn modulates antioxidant enzymes and fatty acids in plasma and tissues compared to SFO. Hence, selection of the fat source may be vital to enhancing the lutein bioavailability.     

Modified Castor Oil Based Polyurethane Elastomers for One-Shot Process

Studies have been carried out on polyurethane elastomers based on modified castor oil in combination with different molecular weights of polyethylene glycol and polymeric methylene diphenyl-4,4′-diisocyanate (PMDI). The resulting polymers were cast into molds and the moldings were characterized by scanning electron microscopy and thermogravimetric analysis. Mechanical properties such as tensile strength, elongation at break, hardness, abrasion resistance, and compression set were measured. There is an increase in the flexibility of polyurethanes with increase in molecular weight of PEGs added to modified castor oil.     

Effect of Cathode Microstructure on Arc Velocity and Erosion Rate of Cold-Sprayed Copper Cathodes in a Magnetically Rotated Atmospheric Pressure Arc

Atmospheric pressure arc velocity and erosion measurements were performed on cold-sprayed cathodes in a continuously running arc system. Ultrahigh purity (99.99% pure) argon was used as plasma forming gas. An external magnetic field of 0.10 T was used to rotate the arc, which was operated at a constant power of 6 kW (40 V). Cathodes having microstructures with mean grain sizes, ranging from 1.12 to 3.06 μm, were produced using cold spraying (CS) and annealing methods. CS cathodes were tested in their as-sprayed state and annealed state. Annealed CS coatings with near equi-axed grains of 2.29 μm average size gave 60% higher steady-state arc velocities and up to 50% lower erosion rates than massive copper cathodes having 20-23 μm average grain size. An effect of cathode microstructure on arc velocity and on arc erosion rates was observed.     

Miscibility study of cellulose acetate/carboxylated poly(vinyl chloride) blend in cyclohexanone by viscosity,ultrasonic velocity,refractive index,and polarizing microscopic methods

The viscosity, ultrasonic velocity, refractive index, and density of cellulose acetate/carboxylated poly(vinyl chloride) (CA/C‐PVC) blends in cyclohexanone, a common solvent, were measured at 30°C. After casting films of the blend for a 50:50 composition, polarizing micrographs were taken. Using the viscosity data, the interaction parameters were computed by employing two different equations. These values indicated that the CA/C‐PVC blend is miscible. This was confirmed by ultrasonic, refractive index, density, and polarizing microscopic methods. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 557–561, 2001     

Preparation and properties of semi-interpenetrating polymer networks based on polyurethane ionomer/polyvinyl chloride

Semi-Interpenetrating polymer networks (IPNs) of polyurethane anionomers (IPU) with Polyvinylchloride (PVC) were synthesized and characterized by Fourier-transform infrared spectrophotometer (FT-IR), thremogravimetric analysis (TGA) and mechanical studies. The synthesized semi-IPNs were found to be compatible. The hydrogen bonding interactions and the thermal stabilities are discussed based on FT-IR analysis and thermogravimetric analysis (TGA). Tensile strength and hardness increase with increasing NCO/OH ratio and ionic content of the polyurethanes.     

Function-cognate mechanisms: General theory and applicationGleichwertige Übertragungsgetriebe: Allgemeine theorie und ihre anwendung

A general algebraic approach using comparison of coefficients in the input-output displacement equation with appropriately grouped terms is developed rigorously for the identification of function-cognate mechanisms. These are mechanisms that give exactly the same relationship between the displacements of the input and output links. Several single-loop mechanisms are investigated to establish the existence or nonexistence of function cognates.     

Two-photon ratiometric sensing of Hg2+ by using cysteine functionalized Ag nanoparticles

We have demonstrated a novel two-photon sensing strategy to detect mercury ions with high selectivity and sensitivity. This sensing approach is based on the observation that addition of Hg(2+) into a cysteine functionalized Ag nanoparticle solution could significantly enhance their two-photon emission. An enhancement factor of up to 100 fold was obtained when mercury was added. A detection limit of as low as 65 nM could be achieved. The sensitivity and sensing range can be easily tuned. Compared to the conventional colorimetric or extinction spectrum based methods, this scheme offers improved sensitivity, quantitative detection of Hg(2+) with a larger dynamic range, and allows detection deep into biological environments such as cells and tissues where deep penetration is required. The sensitivity could be further improved by using two-photon microscopy with the additional advantages of 3D detection and mapping.     

Kinetics of picosecond laser treatment of silver nanoparticles on ITO substrate

In this work, the effect of ITO substrate on Ag NP size, morphology and photoinduced absorption depending on the time of 30 ps laser treatment were explicitly studied. Silver nanoparticles with an average diameter of ∼40 nm supported on indium tin oxide (ITO) were irradiated with a tightly focused pulsed laser (doubled frequency beam) at 532 nm. The size transformation of silver nanoparticles induced by a single pulse of Nd:YAG laser (λ = 532 nm, pulse width = 30 ps) was directly observed by an electron scanning microscopy (FE-SEM) on indium tin oxide surface. Simultaneously the change in the absorption and the corresponding derivatives are also presented. These morphological changes are accompanied by a significant change in the optical absorption properties of the array. This study demonstrates that picosecond laser irradiation is an excellent technique to operate and control the properties of nanostructured materials on solid supports.