Tests plate

Potts [55] used the method in his screening of 31 commercially available polymers for biodegradability. Other studies, where the growth of either mixed or pure cultures of microorganisms, is taken to be indicative for biodegradation, have been reported [4]. The validity of this type of test, and the use of visual assessment alone has been questioned by Seal and Pantke [56] for all plastics. They recommended that mechanical properties should be assessed to support visual observations. Microscopic examination of the surface can also give additional information. 

A variation of the plate test, is the clear zone technique [57] sometimes used to screen polymers for biodegradability. A fine suspension of polymer is placed in an agar gel as the sole carbon source, and the test inoculum is placed in wells bored in the agar. After incubation, a clear zone around the well, detected visually, or instrumentally is indicative of utilisation of the polymer. The method has for example been used in the case of starch plastics [58], various polyesters [59-61], and polyurethanes [62]. 

A positive result in an agar plate test indicates that an organism can grow on the substrate, but does not mean that the polymer is biodegradable, since growth may be on contaminants, on plasticisers present, on oligomeric fractions still present in the polymer, and so on. Therefore, these tests should be treated with caution when extrapolating the 

---

Celanese Chemical Co., Inc., Mutagenicity Evaluation of n-PropylAlcohol in the Ames Salmonella Microsome Plate Test, Litton Bionetics, Inc., Kensington,... 

The progress of the photolysis can be followed either by observing the disappearance of the typical nitrite bands between 1600 and 1680cm (6.25 and 5.95 ju) in the infrared spectrum or by disappearance of the diphenyl-amine-sulfuric acid spot plate test. 

Barium. Pptd by the addn of Ba chloride to w-sol salts of MEDNA (Ref 2 3) it has the least expl effect in lead plate test when primed with MF (Ref 7)... 

Salts. HgOH+ salt. It is prepd from the Na salt and Hg(II) chloride. The Pb block expansion test gives 7.5cc/2g, but it has little effect in the Pb plate test (Ref 13)... 

It fonns expl heavy metal salts, which according to Urbanski, are weaker initiators than the corresponding metal salts of methylenedi-isonitramine. The decreasing order of brisance of these salts, when primed with MF, in the Pb plate test were Na, Ca, Ba, H and Pb Refs 1) T. Urbanski T, Wesolowski, Wiad-TechnUzbr 18, 28 (1932) 2) T. Urbanski,... 

Twenty-four hundred grams (25.6 mol) of phenol, 1645 g of 37 wt % formaldehyde (20.3 mol), and 30 g (0.33 mol) of oxalic acid were charged to a 5-L, three-necked resin kettle. The mixture was stirred and refluxed until the distillate was free of formaldehyde (1-3 h) then water was distilled from the mixture until the resin temperature reached 154°C. The viscosity of the resin at this point at 150°C was such diat 105 s was required for flow in an inclined plate test. The pressure was slowly reduced while a slow current of nitrogen was bubbled through the resin, and the mixture was heated to 175°C at 6 mm Hg. Approximately 6 wt % phenol was recovered then the resin was poured into an aluminum dish and cooled. The resin had a melt viscosity of 510 s at 150°C. 

The first official test was published by the Food, Drug and Insecticide Administration of the US Department of Agriculture, in which portions of the preparation were placed on the surface of nutrient agar inoculated with Staph, aureus. After incubation the zones of inhibition, if ary, around the preparation were measmed. This test was modified later by incorporating 10% of horse serum in the agar to simulate conditions in a woimd and a control consisting of unmedicated base was also used in each experiment. This test is known as the cup-plate test (see also section 3.6.3 and Fig. 11.5). 

Pain Mouse hot-plate test Induces nociception [46]... 

The furan derivative (23) has been tested in vivo in tests of motor activity (open-field test) and antinociception (hot-plate test) as well as its capacity to enhance the hypokinetic and/or analgesic actions of subeffective doses of... 

The hot plate test with a 55 °C platform was used to measure latency to hindlimb lick at 12 or 18 minutes postinjection in rats. 

More rudimentary tests to identify the stability of powders are the so-called "hot plate" tests. Here, the substance is placed in a well-defined manner (circular, specified thickness of the layer, and so forth) on a hot plate with a controlled temperature. The temperature in the center of the layer is recorded continuously, and the progress of the self-heating is followed. Observations are made if self-heating of the substance occurs, the induction period of such self-heating, and the extent of the effect such as smoldering or spontaneous ignition. 

Both self-heating and self-ignition characteristics are commonly determined by adiabatic tests (self-heating) and hot-plate tests (self-ignition). These tests are limited in their applicability because they do not fully simulate the plant conditions. 

B21. Banhidi, Z. G., Improvements in the agar-plate test for thiamine factors with Lactobacillus fermenti 36. Analyst 84, 657-659 (1959). 

Reversion Tests Background. There are several excellent references describing the background and use of bacteria for reversion tests (Brusick, 1987 Gatehouse et al., 1990). Three different protocols have been widely used plate incorporation assays, treat and plate tests, and fluctuation tests. These methods are described in detail in the following sections. Fundamental to the operation of these tests is the genetic compositions of the tester strains selected for use. 

Data Analysis. Data from the fluctuation test described above are analyzed by an appropriate statistical method as described in Robinson et al. (1989). Data from plate assays are analyzed as described in Arlett et al. (1989) for treat and plate tests. 

Gatehouse, D. and Wedd, D.J. (1984). The differential mutagenicity of isoniazid in fluctuation assays and Salmonella plate tests. Carcinogenesis 5 391-397. 

Zeiger E, Pagano DA. 1984. Suppressive effects of chemicals in mixture on the Salmonella plate test response in the absence of apparent toxicity. Environ Mutagen 6(5) 683-694... 

Materials salicylic acid, methanol, distilled water, 10-mL graduated cylinder, Beral pipette, 250-mL beaker, concentrated sulfuric acid, top or bottom of a petri dish, cotton ball, small test tube, balance, weighing paper, hot plate, test-tube holder... 

---