Differences in the evaluation of soil phosphorus status by three soil tests (Mehlich 3, extraction with NH4-acetate and water extraction) were tested on 63 agricultural soils with different agrochemical characteristics from the territory of the Czech Republic. Differences between the colorimetric determination of phosphorus and ICP technique were studied. The median of the values of phosphorus ...

The National Institute of Standards and Technology (NIST) candela is maintained via standard photometers which have shown long-term stability of better than 0.1 % per year. The detector-based method has allowed us to reduce the uncertainties of calibrations and to expand the range of calibration capabilities. There have been several new developments in photometry at the NIST. A high-illuminance...

Tristimulus colorimetry and diffuse reflectance spectroscopy (DRS) are white-light skin reflectance techniques used to measure the intensity of skin pigmentation. The tristimulus colorimeter is an instrument that measures a perceived color and the DRS instrument measures biological chromophores of the skin, including oxy- and deoxyhemoglobin, melanin and scattering. Data gathered from these too...

PURPOSE To measure the arterial input function (AIF) in a mouse tail at high temporal resolution with signal phase of MR projections. METHODS The technique involves the acquisition of one 2D image before injection, followed by a series of projections before, during, and after contrast injection. Differences in the signal phase, relative to the mean preinjection phase, were calculated and conv...

As an important biomarker and therapeutic target, telomerase has attracted considerable attention concerning its detection and monitoring. Here, we present a colorimetry and surface enhanced Raman scattering (SERS) dual-mode telomerase activity detection method, which has several distinctive advantages. First, colorimetric functionality allows rapid preliminary discrimination of telomerase acti...

BACKGROUND AND METHODS Several standard powdered black pigments were characterized by means of thermogravimetry TG-DTG and allied techniques. These pigments were used to make standard plaster frescoes at this purpose prepared. The latter ones were subjected to Raman and reflectance analysis. The results obtained, together with TG data, were chemometrically processed and used to identify an anal...

By H. H. ROSTORFER, PH.D., AND R. H. RIGDON, M.D. M ARKED changes in color indices, cell volume indices, and relative cellular hemoglobin indices have been observed by Rostorfer and Rigdon’ in the blood of ducks during the course of severe malarial infections and during the period of recovery. A difference in the amounts of functional hemoglobin calculated from the oxygen capacity of the blood ...

LLE Review, Volume 73 59 Ever since cholesteric liquid crystals (CLC’s) were discovered in 1888,1 CLC colors have been noted for their qualitative vividness and luminosity;2 however, there have been few quantitative colorimetric studies examining CLC’s as colorants. We will describe how CLC’s produce color, what colorimetric studies have been done on them, and how we have extended and improved ...

The antioxidant potential of the 99% methanolic extract of leaves of Muntingia calabura was assessed by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and total phenolic content was measured by Folin-Ciocalteau (FC) by Singleton and Rossi using Gallic acid and Tannic acid as the calibration standard. Moreover Muntingia calabura leaf extract showed strong reducing power and significant antioxidant a...