A rapid method for simultaneously determining activity of Sr and Sr in a non-equilibrated Sr/Y system without Cerenkov counting.

A method for determining activity of Sr and Sr in a sample where Sr and Y are not in equilibrium is presented. The method consists of an experimental design and equations for accurately calculating activity of Sr and Sr based on Y particle counts and the total counts of particles emitted from Sr, Sr, and Y in a sample. The equations are derived based on chemical separation sequences, particle counting sequences, and the Bateman equation.

Simple methods for calculating activity of a parent-progeny system.

Based on the original work of Rutherford (Radio-activity, 1905) and Bateman (Proc Camb Philos Soc 15:423-427, 1910), the authors designed two schemes consisting of explicit equations as simple methods for accurately obtaining activity of Sr and Y before they reach secular equilibrium. Application of the methods to the Sr/Y system where Sr and Y are not in equilibrium will substantially reduce the time needed for determining activity of Sr because neither sequential measurements of Sr or Y (up to about 2 weeks) nor waiting for Sr and Y to reach equilibrium (more than 3 weeks) will be needed. We also implemented the explicit equations for decay/ingrowth correction of progeny's activity and applied them to the Zr/Nb system.

Estimating Bacterial Concentrations in Fibrous Substrates Through a Combination of Scanning Electron Microscopy and ImageJ.

Conventional signal-based microanalytical techniques for estimating bacterial concentrations are often susceptible to false signals. A visual quantification, therefore, may compliment such techniques by providing additional information and support better management decisions in the event of outbreaks. Herein, we explore a method that combines electron microscopy (EM) and image-analysis techniques and allows both visualization and quantification of pathogenic bacteria adherent even to complex nonuniform substrates.

A portable real-time in situ gamma-ray analysis system.

A portable CeBr based gamma-ray detection system was designed and built for rapid turnaround, high throughput, real-time, and in situ sample analysis. The new technique allows automated data transmission from the field unit to a central laboratory controller to ensure laboratory quality of the data collected by field users without gamma-ray spectroscopy expertise. The method validation data indicates that the system's data quality objectives are adequate for radiological or nuclear emergency response or targeted surveillance programs where gamma-ray analysis is needed.