Voltage-clamp fluorometry (VCF) supplies information about the gating transitions of voltage-gated proteins. Changes in fluorescence intensity dye attached to a part protein that undergoes conformational rearrangement upon alteration membrane potential by electrodes constitute signal. The VCF signal is generated quenching and dequenching as traverses various local environments. Here we studied ...

The fluorescence spectra of the material obtained when estrone, estradiol-178, and estriol are heated with sulfuric acid have already been described (l-3), together with their relative fluorescence intensities in response to esciting light of different wave lengths (2). However, in order to design the most favorable optical conditions for the fluorometry of these estrogens in urinary extracts a...

Current approaches for assessing human health risks associated with cyanotoxins often rely on the quantification of microcystin. Significant limitations of current approaches are cost and time to obtain a result. To address these challenges, a numerical index for screening microcystin risks above the World Health Organization's (WHO) low-risk threshold for microcystin was developed for eutrophi...

We describe a mechanized method for determining total estrogens in plasma during the last trimester of pregnancy. This method involves rapid enzymic hydrolysis, automatic extraction (in a tube) with cyclohexane/ethyl acetate, purification of the extracted material by anion-exchange chromatography on a disposable "mini-column" of Dowex AG1 X 2 (acetate form), and continuous-flow fluorometric qua...

HE INCREASING USE of fluorimetry in routine analysis is reflected in a variety of commercially available instruments which, in many instances, are either prohibitive to the average laboratory due to high cost or lack proper sensitivity. Unlike the Beckman DU spectrophotometer, its clinical counterpart, known as Model B, is not provided with a standard fluorimetric attachment. The versatility of...

An automated system for the sensitive, reproducible determination of malate dehydrogenase activity in serum is described and evaluated. After incubation of serum at 25#{176}C and double dialysis, fluorometry is used to measure the disappearance of NADH during reaction. Certain precautions are necessary to maintain the stability of NADH and oxaloacetate and to assure washout of adsorbed serum co...

Single-walled carbon nanotubes (SWCNTs) are a family of structurally related artificial nanomaterials with unusual properties and many potential applications. Most SWCNTs can emit spectrally narrow near-IR fluorescence at wavelengths that are characteristic of their precise diameter and chiral angle. Near-IR fluorimetry therefore offers a powerful approach for identifying the structural species...

Using the Kober-lttrich fluorescence procedure, automated fluorometry was applied to the assayof individualestrogensand their 3-methyl ether derivatives in the purified urinary extracts of nonpregnant women. The values obtained by using this new automated scheme were comparedwith those obtained by the manual time-decay modification of the Slaunwhite-Engel fluorescence method; the comparisonshow...