A fast strategy to sequentially separate and determine 90Sr, 210Pb and 210Po in water samples using Sr resin

This study presents a rapid and novel sequential separation strategy based on extraction chromatography for determining 90Sr, 210Pb and 210Po in drinking water samples. It involves the use of Sr resin for the separation and then liquid scintillation counting and alpha spectrometry for the determination. The experimental results obtained showed that the proper acidic solution to quantitatively retain the aforementioned radionuclides is 3 M HNO3. The optimum eluents were determined for obtaining quantitative recoveries (70–80%) of 90Sr, 210Pb and 210Po. The method was validated with intercomparison water samples and is satisfactory in terms of minimum detectable activities, which are 50% lower than that established in RD 314/2016.

What You Extract Is What You Get: Different Methods of Protein Extraction from Hemp Seeds

Cannabis sativa L. seeds are rich in essential polyunsaturated fatty acids and highly digestible proteins, with a good nutritional value. Proteomics studies on hempseed reported so far have mainly been conducted on processed seeds and, to our knowledge, no optimization of protein extraction from hemp seeds has been performed. This study investigates the SDS-PAGE profile of hempseed proteins comparing different methods of extraction, (Osborne sequential extraction, TCA/acetone, MTBE/methanol, direct protein solubilization of defatted hempseed flour), two conditions to keep low temperature during seed grinding (liquid nitrogen or ice) and two solubilization buffers (urea-based or Laemmli buffer). Among the tested conditions, the combination of liquid nitrogen + TCA/acetone + Laemmli buffer was not compatible with SDS-PAGE of proteins. On the other hand, urea-based buffer achieved more reproducible results if combined with all the other conditions. TCA/acetone, MTBE/methanol, and direct protein solubilization of defatted hempseed flour demonstrated a good overview of protein content, but less abundant proteins were poorly represented. The Osborne sequential separation was helpful in diluting abundant proteins thus enhancing the method sensitivity.

Closed-Loop Recycling Dual-Mode Counter-Current Chromatography with Specified Sample Loading Durations: Modeling of Preparative and Industrial-Scale Separations

We previously reported on a new counter-current chromatography (CCC) operating mode called closed-loop recycling dual-mode counter-current chromatography (CLR DM CCC), which incorporates the advantages of closed-loop recycling (CLR) and dual-mode (DM) counter-current chromatography and includes sequential separation of compounds in the closed-loop recycling mode with the mobile x-phase and in the inverted-phase counter-current mode with the mobile y-phase. The theoretical analysis of several implementations of this separation method was carried out under impulse sample injection conditions. This study is dedicated to the further development of CLR DM CCC theory applied to preparative and industrial separations, where high-throughput operation is required. Large sample volumes can be loaded via continuous loading within a specified time. To simulate CLR DM CCC separations with specified sample loading durations, equations are developed and presented in “Mathcad” software.

Ensuring non-collision and safe distancing of a large number of spacecraft when launched by the Fregat upper stage

The paper proposes a method for forming a cyclogram of separating a large number (on the order of several tens or more) of spacecraft in one orbit, and determining the upper stage orientation program, which ensures a safe distancing of the spacecraft both among themselves and with the upper stage itself. We consider the application of this technique for the simultaneous and sequential separation of the spacecraft, as well as their combination. In this case, the relative speeds of object separation can be the same or different. We also give recommendations on how to carry out the maneuvers to de-orbit the upper stage after the completion of all operations in which the requirements for spacecraft surface non-contamination from the upper stage engine are met. The developed technique has been repeatedly tested during cluster launches of the Fregat upper stage.