Heto powerdry ll3000 freeze dryer

The wafers were prepared from 1% w/v solutions of HEC and its derivatives in deionised water. 1.5 g of HEC, and HECGMA solutions were poured into each well in 24 well plates. The plate was covered with holed aluminium foil and was left under a fume hood for an hour. It was then frozen in a freezer at −20 °C overnight. The wafers were prepared by freeze-drying in a Heto Power Dry LL3000 Freeze Dryer (Thermo Scientific UK Ltd., Leicestershire, UK) over 48 h. The wafers were placed in sealed containers and stored in a fridge at 4 °C.

Twelve-hour-old fourth instar nymphs of the wingless red and green A. pisum were transferred into transparent plastic dishes (90 mm in diameter; 20 aphids per dish) for starvation treatment. The aphids were collected at hourly intervals for 24 h. The collected samples were then immediately used in energy reserve assays. The aphids were freeze-dried for 36 h in a lyophilizer (Heto PowerDry LL3000 Freeze Dryer, Thermo Fisher Scientific, United States); 2 mg of dried samples was weighed out using a high-precision electronic balance (MSA3.6P, Sartorius, Germany) at ambient temperature. The aphids were transferred into a 1.5-mL microtube, homogenized by a micropestle, and dissolved in 800 μL of solution buffer (100 mM KH₂PO₄, 1 mM DTT, 1 mM EDTA, pH 7.4) for further analysis. This experimental step had three replicates.

Interpolymer complexes were prepared by mixing separate 0.1 wt % polymer solutions in deionized water. Solutions were mixed to give different unit molar ratios of the polymer components. The complexation between Carbopol and POZ was evaluated in water without adjusting pH and also at pH 2 (which was adjusted by addition of 0.1 mol/L HCl). The obtained interpolymer complexes were left for 2 days in the media, and then they were separated, washed twice with the solvent and freeze-dried in a Heto PowerDry LL3000 Freeze Dryer (Thermo Scientific, Loughborough, UK) for at least two days. The composition with the maximum concentration yield was selected for the tablet formulation.
Infrared spectra of the interpolymer complexes and pure components were recorded using Nicolet Nexus FTIR spectrophotometer Thermo Scientific, Loughborough, UK) in KBr pellets, at a resolution of 4 cm⁻¹ and 32 scans. Glass transition temperatures (T_g) were determined using Mettler-Toledo Differential Scanning Calorimeter, DSC 822^e (Gießen, Germany), heating from 20 to 180 °C at 20 °C·min⁻¹, and the T_g was taken as the mid-point of the curve inflection.