Temperature centrifuges

If the initial oil concentration in the sludge is high, high-temperature centrifugation with biodegradable surfactant is recommended to lower the concentration to a reasonable value. The resulting solid extract can be mixed with cement to obtain cement of a quality suitable for masonry. 

A total of 21-25 4-year-old roots were collected from 1 m x 1 m plots from five ginseng farms in Norfolk County, Ontario. Root sections with diameter between 4 and 10 mm were examined. A total of 400 mg of ground root was added to 10 mL of 70% methanol and sonicated for 25 min at room temperature, centrifuged and the supernatant removed. The extraction was repeated twice using 10 and 4 mL,... 

Remove frozen assay plates from freezer and thaw at room temperature. Centrifuge plates at 700 for 1 min to collect siRNA at the bottom of the wells. 

Spin the cells down in a pre-warmed (room temperature) centrifuge for 7 min at 140 ref. 

Pipette 0.2 ml of CSF or amniotic fluid into an Ultrafree 10000 Filter Unit (Millipore), add 40 pi of water, 30 pi of 30% (w/v) TCA, and 1 mg of Mn02 (see above) shake for 5 min at room temperature. Centrifuge for 30 min at 2000 xg. Immediately transfer the clear supernatant into a vial. For sepiapterin determination, samples should be analyzed without oxidation. 

Keep the cell wall pellet in the plastic centrifuge bottle to minimize losses. Resuspend the pellet in 100 ml of 50 mM HEPES buffer, pH 6.7/20% ethanol. Stir for 6 hr at room temperature. Centrifuge at 9800 x g for 20 min at room temperature. Remove the supernatant as before and retain at 4°C. 

Volatile solvents and solutes, up to 0.3 ml, were removed by room temperature centrifugal vacuum (SpeedVac, Savant) in siliconized tubes pre-loaded with 200 pg BSA and 30 fig bacitracin. We found that trace amounts of mercaptoethanol seriously elevate the blanks in the standard radiolabeled isooctane partition assay (13), and residues of TFA require careful readjustment of the pH of the tissue culture medium. Therefore, evaporation was routinely extended for approximately 30 minutes beyond the time of apparent dryness to ensure good removal of solvent modifiers. Dried residues were dissolved in 0.85 ml of modified culture medium 199 (1) by one minute of ultrasonication through the walls of the plastic tube, then left to stand for ca. 30 minutes and finally vortex mixed. 

An approximate idea of the distribution of acid phosphatase activity in human tissues, regardless of the nature of the acid phosphatase, may be obtained from the studies of Reis (R2) on 5 -nucleotidase and other phosphomonoesterases. He prepared aqeuous homogenates of postmortem tissue in the proportion of 20 parts of water to one of tissue, allowed these to autolyze for 2 days at room temperature, centrifuged the material, and employed the supernatant fluid. The assay mixture consisted of 0.4 ml of a suitable buffer, 0.1 ml of 0.005 Af phenyl phosphate as substrate, and 0.1 ml of tissue extract. The enzyme activity was expressed as micrograms of phosphorus hydrolyzed per hour per milligram of wet... 

Sample preparation Incubate cells in 2 mL 100 mM pH 3.0 ycine-HCl buffer for 2 h at room temperature, centrifuge at 5600 g for 5 min, inject an aliquot. 

Dissolve the dried protein pellet in 8 M urea/2 M thiourea and mix by shaking for 20 min at room temperature. Centrifuge the solution for 15 min at 21,000 x g and transfer the supernatant into a new noicrotube. 

Reflux this solution for 10 mm and cool to room temperature. Centrifuge the resulting reddish brown solution for 20 min at 2500g and 4°C. 

Sample preparation Dilute urine ten-fold with water. 50 pL Plasma or 100 p,L diluted urine + 150 p,L MeCN, vortex for 30 s, incubate at room temperature for 5 min, centrifuge at 1500 g for 10 min. Remove a 100 pL aliquot of the supernatant and add it to 100 pL triazole solution, heat at 50° for 15 min, cool to room temperature, centrifuge at 1500 g for 5 min, inject a 20 p,L aliquot of the supernatant. (IHazole solution was 13.81 g 1,2,4-triazole in 60 mL water, pH adjusted to 10.0 0.05 with saturated NaOH solution, made up to 100 mL with water.)... 

Transfer spin column into anew 1.5-mL tube and pipet 11 pL of RNase-free water directly onto the spin column membrane. Ensure that the water is dispensed directly onto the membrane and leave it to stand for 5 min at room temperature. Centrifuge for 1 min at maximum speed (12,000g) to elute. To increase the yield, recover the eluate and place it back onto the membrane. Leave to stand for a further 2 min at room temperature. Centrifuge for 1 min at maximum speed (12,000g) to elute. 

Add enough 1.0% trifluoroacetic acid/60% ACN to cover gel pieces. Shake or sonicate for 10 min at room temperature, centrifuge, and remove supernatant and combine with supernatant from previous step. 

Extraction should be carried out in subdued light at low temperatures. If cell disintegration is deemed necessary, either ultrasonication or cell grinding (manual or automated) may be used. In our experience, 3 min of ultrasonication followed by low temperature centrifugation (4°C) for 30 min at 6000 rpm is sufficient to extract well over 90% of the pigments in particulate material and to remove particulate debris. Hie supernatant may be analysed by HPLC without any further clean-up. In fact, additional handling should be avoided as some carotenoids are extremely sensitive to oxidation. 

Fold the filter (plankton inside) and place it in a small (5-15 ml) glass, pestle-type homogenizer. Add 2-3 ml 90% acetone. Grind 1 min at about 500 rpm. Transfer to a centrifuge tube and wash the pestle and homogenizer 2 or 3 times with 90% acetone so that the total volume is 5-10 ml. Keep 10 min in the dark at room temperature. Centrifuge (Note e) for 10 min at 4000-5000 g (Note /). Carefully pour into a graduated tube so the precipitate is not disturbed and if necessary dilute (Note g) to a convenient volume (Note h). 

There are liquid-liquid extraction systems where the residence time in the device should be very small ( 10 s) to reduce degradation, for example in penicillin extraction carried out at a low temperature. Centrifugal devices (e.g. Podbielniak) are utilized for such systems. As illustrated schematically in Figure 8.1.35(e), this device contains a number of concentric perforated shells around a central shaft rotating rapidly around a central axis. The two liquids are introduced from opposite ends into different tubular channels in the shaft the heavy liquid is introduced near the shaft, whereas the light liquid is introduced near the periphery. 

Allow cells to settle to the bottom of the plate by gravity at room temperature. Centrifugation or incubation at 37 °C will give a less uniform distribution, and an even distribution is essential for optimal cardiac differentiation down the line. 

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