Whatman 3 filter paper

Pieces of Whatman #3 filter paper were cut to size (1.0 cm²) from strips containing the blood collected from the fingertips of the study participants. The filter paper and 330 μL of PBS-0.01, pH 7.2, were added to Eppendorf microtubes and incubated at 4°C for 16 hours.

The test cell was a sandwich type cell, whose structure was made of two end pieces of acrylic (100×90×13 mm each) and at least two sections of clear PVC pipe (88 mm outer diameter, 6 mm wall thickness). Unless otherwise noted two 30 mm long lengths of pipe composed the standard test cell. The cells were held together by compression from four bolts in the corners of the cell. Circular gaskets made of three layers of parafilm were placed between the junctions of each component to form a water-tight seal upon compression. A single circle of Whatman 3 filter paper (Frederick, MD) was used as the membrane separating the two sides of the cell. The Al electrode in the cell was derived from Al foil (98.5% Al) and was routinely 57 cm². The platinum electrode was Pt wire of 0.3 mm diameter and an exposed surface area of 4.56 cm². The power curve of the cell was performed with N. oceanica IMET1 at pH 10 on the high pH side and f/2 medium with a pH of 7 on the low pH side. Voltage was measured at set resistances between 5–10,000 Ω.

The CL (%) was calculated as the weight before cooking compared to the weight after cooking. Expressible moisture (EM, %) was evaluated as previously described [20 ]. Sausage samples (n = 4) were prepared as cubes with an approximate weight of 1.5 g. Prepared samples were wrapped in three pieces of Whatman #3 filter paper and centrifuged at 1,660×g for 15 min in a centrifuge (VS-5500, Vision Science Co., Ltd, Seoul, Korea). The EM was calculated from the weight before and after centrifugation.

A 1% agarose gel solution was prepared and equilibrated at 50°C in a water bath. Agarose gel solution was added with anti-HA sheep serum (ref. 03–242, NIBSC, London, United Kingdom) with a final concentration of 1/1000. The agarose-antibody mixture was casted and left to cool in a Bio-Rad gel-casting module for at least 15 minutes. In the gel, 4 mm wells were punched before addition of 20 μl of sample in each well. For all the SRID experiments, a calibration curve was determined with standard samples of purified recombinant HA of A/H1N1/Puerto Rico/8/1934 strain from Protein Sciences Corporation (Meriden, USA) at concentrations ranging from 7 to 30 μg/ml. All the samples were subjected to detergent treatment for 15 minutes on a rocker platform (1% Zwittergent final concentration). Sample diffusion in the gel took place for 18–24 hours at room temperature. The gel was dried using Whatman #3 filter paper (Kent, United Kingdom), rinsed with deionized water, and stained with Coomassie Blue R-250 for 15 minutes and de-stained using a 7.5% acetic acid and 10% ethanol solution. Result analyses were performed on gel photograph where the diameter of the reference standards and samples were measured using Image-J software (Pixel-aspect ratio = 1, known distance = 4 mm) allowing further calculation of sample concentration through linear correlation.

DBS were prepared by spiking P. falciparum D6 parasite culture into whole blood and spotting 10 μL onto Whatman 903 Protein Saver cards (903 cards) or Whatman 3 filter paper (W3). Extraction was performed on 6 mm spots. Two spots were extracted for each sample, in one, 2-mL microcentrifuge tube with 300 µL PBST extraction buffer. The tubes were vortexed at maximum speed (3200 rpm) for 10 min. Afterwards, tubes were centrifuged to remove bubbles and spin down the DBS paper. The supernatant was then removed and analysed by ELISA.

We analyzed headspace gas of soils for CO₂ concentration and δ¹³CO₂ three times during the week-long incubation using a LI-Cor 6262 (LI-Cor Biosciences Inc. Lincoln, NE, USA) and a Picarro G2201 (Picarro Inc., Sunnyvale, CA, USA), respectively. Prior to incubation we analyzed soil MBC using the chloroform-fumigation extraction method on 10 g of soil. One sub-sample was immediately extracted with 25 ml of a 0.05 M K₂SO₄ solution, while a second sub-sample was first fumigated with chloroform (for 5 days), after which it was similarly extracted. Following K₂SO₄ addition, we agitated soils for 1 h, filtered the extract through a Whatman #3 filter paper, and dried the filtered solution (60 °C, 4 days). Salts with extracted C were ground and analyzed for total C using an elemental analyzer coupled to a mass spectrometer. MBC was calculated as the difference between the fumigated and immediately extracted samples’ soil C using an extraction efficiency of 0.45 (as per Liu et al.^{26 (link)}).