Selective sequential dissolution for the determination of inorganic indium compounds in the particulate matter of emissions and workplace air.

A speciation method was developed for the determination of inorganic indium compounds in the particulate matter of emissions and from the workplace, based on selective sequential extractions. The main inorganic indium compounds that are expected to be present in the atmospheric particulate matter involving the industrial production of indium and in the manufacture of indium compounds were separated and determined. The procedure has been tested on standard reference materials. The indium recovery was in the range 93 - 105%.     

Pressure broadening of hydrogen sulfide

Microwave measurements of the self-broadening parameters of four pure rotational transitions of H₂S have been carried out in the millimeter and submillimeter wavelength region. The resulting parameters are (in MHz torr^-1): 1_1.0?1_0.1, 7.18±0.5; 2_2.0?2_1.1, 6.78±0.5; 2_1.1?2_0.2, 9.10±0.5; 3_3.0?3_2.1, 7.76 ±0.5. In addition. Anderson theory calculations have been carried out for these transitions and are found to be in good agreement.     

THE PEROXIDATIVE METABOLISM OF TENOXICAM PRODUCES EXCITED SPECIES

The peroxidative metabolism of the nonsteroid anti-inflammatory oxicams generates metabolites of the type expected from a dioxetane intermediae. Therefore, electronically excited metabolites may be expected. Consistent with this possibility, both direct and sensitized light emission are observed when tenoxicam is exposed to horseradish peroxidase or when added to leukocytes, where it undergoes a myeloperoxidase-catalyzed aerobic oxidation. The similarity between peroxidative metabolism with concomitant oxygen uptake and photodegrdation brought about by singlet oxygen addition to the substrate is pointed out. As a whole, the results strengthen the view that electronically excited species should also be considered when analyzing the effect(s) of xenobiotics.     

1,1-Bis(benzenesulfonyl)ethylene: A synthetic equivalent of ethylene 1,2-dipole

1,1-Bis(benzenesulfonyl)ethylene (1) acts as a synthetic equivalent of ethylene 1,2-dipole as it gives with olefins products derived from a postulated dipolar reaction mechanism that can be readily desulfonylated into the formal ethylene adducts.     

High-resolution monitoring of the hole depth during ultrafast laser ablation drilling by diode laser self-mixing interferometry

We demonstrate that diode laser self-mixing interferometry can be exploited to instantaneously measure the ablation front displacement and the laser ablation rate during ultrafast microdrilling of metals. The proof of concept was obtained using a 50-μm-thick stainless steel plate as the target, a 120?ps/110?kHz microchip fiber laser as the machining source, and an 823?nm diode laser with an integrated photodiode as the probe. The time dependence of the hole penetration depth was measured with a 0.41?μm resolution.     

Algebraic conditions on non-stationary subdivision symbols for exponential polynomial reproduction

We present an accurate investigation of the algebraic conditions that the symbols of a non-singular, univariate, binary, non-stationary subdivision scheme should fulfill in order to reproduce spaces of exponential polynomials. A subdivision scheme is said to possess the property of reproducing exponential polynomials if, for any initial data uniformly sampled from some exponential polynomial function, the scheme yields the same function in the limit. The importance of this property is due to the fact that several curves obtained by combinations of exponential polynomials (such as conic sections, spirals or special trigonometric and hyperbolic functions) are considered of interest in geometric modeling. Since the space of exponential polynomials trivially includes standard polynomials, this work extends the theory on polynomial reproduction to the non-stationary context. A significant application of the derived algebraic conditions on the subdivision symbols is the construction of new non-stationary subdivision schemes with specific reproduction properties.     

Photolumiscent Properties of Nanorods and Nanoplates Y<Subscript>2</Subscript>O<Subscript>3</Subscript>:Eu<Superscript>3+</Superscript>

Nanorods and nanoplates of Y₂O₃:Eu³⁺ powders were synthesized through the thermal decomposition of the Y(OH)₃ precursors using a microwave-hydrothermal method in a very short reaction time. These powders were analyzed by X-ray diffraction, field emission scanning electron microscopy, Fourrier transform Raman, as well as photoluminescence measurements. Based on these results, these materials presented nanoplates and nanorods morphologies. The broad emission band between 300 and 440 nm ascribed to the photoluminescence of Y₂O₃ matrix shifts as the procedure used in the microwave-hydrothermal assisted method changes in the Y₂O₃:Eu³⁺ samples. The presence of Eu³⁺ and the hydrothermal treatment time are responsible for the band shifts in Y₂O₃:Eu³⁺ powders, since in the pure Y₂O₃ matrix this behavior was not observed. Y₂O₃:Eu³⁺ powders also show the characteristic Eu³⁺ emission lines at 580, 591, 610, 651 and 695 nm, when excited at 393 nm. The most intense band at 610 nm is responsible for the Eu³⁺ red emission in these materials, and the Eu³⁺ lifetime for this transition presented a slight increase as the time used in the microwave-hydrothermal assisted method increases.     

Method for simultaneous analysis of eight vitamin E isomers in various foods by high performance liquid chromatography and fluorescence detection

The objective of this study was to optimize a method to investigate the occurrence and to quantify the full isomeric composition of vitamin E (α-, β-, γ- and δ-tocopherols and tocotrienols) in 6 vegetables (raw and cooked), 3 herbs/spices, raw and cooked eggs, vegetable oils (canola, olive and soybean), flaxseed and sorghum (flour and seeds) and soy (flour) by HPLC with fluorescence detection. Different conditions of extraction and analysis were tested. The optimized method consisted of direct extraction with solvent (hexane:ethyl acetate, 85:15, v/v). For analysis normal phase column was used with mobile phase consisting of hexane:isopropanol:acetic acid (98.9:0.6:0.5) with isocratic elution and fluorescence detection. Excellent separation of all isomers was obtained along with adequate quantification in the foods analyzed. Recovery rates of standards ranged from 91.3 to 99.4%. The linearity range for each isomer varied from 2.5 to 137.5 ng/mL (R2 greater than 0.995 in all cases). Detection limits ranged from 21.0 to 48.0 ng/mL for tocopherols and from 56.0 to 67.0 ng/mL for tocotrienols, while quantification limits ranged from 105.0 to 240.0 ng/mL for tocopherols and from 280.0 to 335.0 ng/mL for tocotrienols. The optimized method was considered simple, fast and reliable, and also preserved vitamin E isomers when compared to validated methods involving saponification.     

Chitosan and silver nanoparticles as pudding with raisins with antimicrobial properties

Chitosan nanoparticles (CS-NP) containing small silver nanoparticles are reported (Ag@CS-NP). CS-NP was synthesized using tripolyphosphate (TPP) as a polyanionic template. TPP also served to electrostatically attract Ag(+) inside CS-NP, where it was reduced by the terminal glucosamine units of the biopolymer. This procedure is environmental friendly, inexpensive, and permits the synthesis of very small AgNP (0.93-1.7 nm), with only a discrete dependence from the amount of silver nitrate used (5-200mg). The obtained hybrid nanocomposites Ag@CS-NP were characterized by DLS, HRTEM, and HAADF-STEM presenting a mean hydrodynamic diameter of 78 nm. The antimicrobial activity of Ag@CS-NP against Candida glabrata, Sacharomyces cerevisiae, Escherichia coli, Klebsiella pneumoniae, Salmonella, Staphylococcus aureus, and Bacillus cereus corresponded to MIC values lower than for AgNO(3).