The performance of two commercially available high-speed photometers, designed for through-the-plate reading, was evaluated. Linearity of instrumental reading and reproducibility of same-day and 2-day measurements were assessed by least-squares analysis and analysis of variance, respectively. For both instruments, the photometric error was on the order of thousandths of an absorbance unit and w...

A new method for characterizing amniotic fluid is presented. The difference in optical absorbarice between amniotic fluid diluted with distilled water or glycerol is measured. This differential approach is shown to determine the total light scattered by the surfactant-containing lamellar bodies and not to be affected by interfering chromogens. The lamellar body size, number density, and concent...

Maillard reaction (MR) was carried out in L-lysine-D-glucose (Lys-Glu) model system heated at 120°C for 0 to 10 h without pH control. Optical property (UV-Vis absorbance and fluorescence) development of MR was monitored. Antioxidant activity of maillard reaction products (MRPs) was investigated by a series of in vitro tests. The UV-Vis absorbance zero and first-order derivative spectrophotometr...

The size and thickness of organic aerosol particles collected by impaction in five field campaigns were compared to those of laboratory-generated secondary organic aerosols (SOA). Scanning transmission X-raymicroscopy was used tomeasure the total carbon absorbance (TCA) by individual particles as a function of their projection areas on the substrate. Particles with higher viscosity/surface tens...

The influence of shear flow of solvent past poly(methyl methacrylate) chains adsorbed onto germanium oxide from dilute carbon tetrachloride solution (a near-θ solvent) was studied at shear rates from 0 to 4 × 104 s-1 with the new apparatus described in this paper. Both the adsorbed amount and the flow-induced surface orientation (surface dichroism) were measured. The method involved measurement...

objective: bioactive glass 45s5 is a surface reactive glass-ceramic biomaterial, developed in 1969. bag 45s5 with particle size of 20-60 nm has the ability of bone regeneration, broad spectrum antibacterial effect, repairs and replaces diseased or damaged bone. the aim of this study was to evaluate the antibacterial activity and determine mic and mbc values of nano-bag45s5 on streptococcus muta...

Isolation and structural elucidation of prune constituents were performed and total 10 compounds were determined by NMR and MS analyses. A novel compound was identified to be 2-(5-hydroxymethyl-2',5'-dioxo-2',3',4',5'-tetrahydro-1'H-1,3'-bipyrrole)carbaldehyde, and 7 phenolic compounds were isolated from prunes for the first time. In addition, antioxidant activity of them was evaluated on the b...

The samples of spent chlorinated Pt/Al2O3 catalysts that were used in the isomerization process were decoked at elevated temperatures under airflow and different oxygen concentrations. The surface of the catalyst was characterized by thermal gravimetric analysis, differential scanning calorimetry, Brunauer-Emmett-Teller analysis, attenuated total reflection fast Fourier in...

A time-resolved evanescent wave absorption technique is employed in studying the adsorption of a mammalian protein (cytochrome c) from an electrolyte-free solution on a hydrophilic glass surface. The method combines the sensitivity of a fast-scan spectral analyzer and surface specificity of slab optical waveguide (SOWG) technique. While proteins are viewed to undergo an overall irreversible ads...

In this work, two synthetic polyelectrolytes, PSS and PAH, are employed as strong adsorbed surfactants to disperse and stabilize neodymium oxide nanoparticles. The acid-base equilibria of the oxide surfaces of the particles were investigated under different pH conditions in the absence and presence of polyelectrolytes, to optimize particle stabilization through enhancement of the effective repu...