Rubber policeman

The checkers transferred the solvent-moist product to a tared Petri dish by means of a gentle puff of compressed air through the stem of the funnel solid adhering to the filter paper and funnel was transferred to the dish with the aid of a soft rubber policeman, which was also used to spread the product over the surface of the dish. The product was then air-dried for 30 minutes in the hood. 

There might be drops of NG stuck to the sides of the separatory funnel contg the wash waters. By using a rubber policeman on a glass rod, these drops can be collected on the bottom and drawn off into a small tared dish, dried over Ca chloride and weighed... 

If it is desired to transform the carbonates and oxides to sulfates, add a few drops of dil H2S04 (ca 10%) and with the aid of a rubber policeman rub down the sides of the dish moistening them with the liquid in the dish. Evaporate the liquid and heat the dish in the muffle furnace at below dull red (Ref 1)... 

Warm cautiously on a steam bath over a thin sheet of asbestos for 15 mins, breaking up any lumps by very cautious use of a rubber policeman attached to a glass rod. Cool to RT, let settle and decant the ale shellac soln through a small tared, previously ignited and cooled, 30 ml Gooch or Selas crucible. Repeat the extraction with new portions of abs ale until the shellac is completely removed(about 3 times). Transfer... 

Cyanuric triazide is insoluble in water, slightly soluble in cold alcohol, and readily soluble in acetone, benzene, chloroform, ether, and hot alcohol. It melts at 94°, and decomposes when heated above 100°. It may decompose completely without detonation if it is heated slowly, but it detonates immediately from flame or from sudden heating. The melted material dissolves TXT and other aromatic nitro compounds. Small crystals of cyanuric triazide are more sensitive than small crystals of mercury fulminate, and have exploded while being pressed into a detonator capsule. Large crystals from fusion or from recrystallization have detonated when broken by the pressure of a rubber policeman.43... 

Thymidine Uptake Studies. Tritiated thymidine (52 mCi/ anole 0.1 /rCi/ml) was added to cells for 60 min at 37°C. Cells were then washed with PBS, incubated at 4°C for 15 min in the presence of ice cold 5% TCA, rinsed with TCA and scraped from the flasks with a rubber policeman. Cells were again washed with PBS, and solubilized in 0.1N NaOH overnight. Aliquots were assayed for protein (62) and radioactivity (scintillation fluid 100 ml Biosolve (Beckman, Fullerton, CA.), 7g of PPO and 0.6 g of POPOP per liter of toluene). 

Incorporation of Radioactive Precursors into Lipids. The cultures of surface-adhering cells were exposed for 16 h to either 400 pCi of Hp/C- syo (final specific activity, 50 yCi/ ymol) or 10 pCi of / %/, galactose ( the rate of incorporation was linear during this period). After 16 hr. the radioactive medium was removed and the cultures were washed four times with 0.9 NaCl. The cells were removed from the surface with a rubber policeman and suspended in physiological saline. Lipids were extracted by Bligh and Dyer procedure (26) and analyzed for various lipids according to Neskovic, et al. (27)... 

In contrast to tissues, tissue culture cells are readily lysed with detergent [11]. Adherent cells from a culture plate are first scraped using a rubber policeman into a small volume of phosphate-buffered saline (137 mMNaCl, 2.7 mM KC1, 4.3 mM Na2HP04, 1.4 mM KH2P04, pH 7.3) and harvested by centrifugation at 1500 x g for 10 minutes at 4°C. The cellular pellet is resuspended in ice-cold TE so that 1 mL contains 100 million cells. After the addition of 10 volumes of freshly prepared digestion buffer (10 mM Tris-Cl, pH 8, 0.05 EDTA, pH 8, 0.5% Sarcosyl, and 100 pg/mL proteinase K), the sample is incubated at 50°C for 3 hours. DNA is recovered by ethanol precipitation after extraction with phenol, phenol-chloroform, and chloroform as described earlier. 

For these studies cells must be harvested mechanically, e.g. by scraping with a rubber policeman or by the use of chemicals (e.g. alkali, acid or detergent) which lead to instantaneous death of the cells from which various products may then be isolated. 

Fig. 4.1. Scrapers used to remove cells from surfaces. The upper scraper is used to scrape cells from inside roller bottles. The blade folds forwards allowing it to pass through the narrow neck. By pushing against the bottom of the bottle the blade opens as shown and the shape of the arm prevents further movement. The middle scraper is a rubber policeman fitted to a bent glass rod. It is used for scraping cells from smaller bottles. The lower scraper is used for dishes where the edges of the cut silicone bung allow cells to be removed efficiently from the corners of the dish.

Pour the mixture through the filter, first decanting most of the liquid into beaker 2, and then carefully transferring the wet solid into the funnel with a rubber policeman. Collect all the liquid (called the filtrate) in beaker 2. 

Moisten the filter paper with distilled water, turn on the water aspirator, and filter the copper through the Buchner funnel. With a rubber policeman move any residue left in the beaker to the Buchner funnel then rinse down all the copper in the beaker with water from a wash bottle and transfer to the Buchner funnel. If filtrate is cloudy, refilter, slowly. Finally, wash the copper in the funnel with 30 mL of acetone (to speed up the drying process). Let the copper remain on the filter paper for 10 min. with the water running to further the drying process. 

Sodium Carboxymethylcellulose Substrate (0.2% w/v) Transfer 200 mL of water into the bowl of the Waring blender. With the blender on low speed, slowly disperse 1.0 g (moisture-free basis) of the Sodium Carboxymethylcellulose into the bowl, being careful not to splash out any of the liquid. Using a rubber policeman, wash down the sides of the glass bowl with water. Place the top on the bowl and blend at high speed for 1 min. Quantitatively transfer to a 500-mL volumetric flask, and dilute to volume with water. Filter the substrate through gauze before use. 

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