Test chambers labelling

Table IX presents chamber data obtained in only one large test chamber identified as A on medium density fiberboard made at one plant. A medium density fiberboard "set" is a specific production run. The columns are labeled the same as the particleboard Table VIII described above. The "Normalized Chamber Concentration" is based on a 0.6 ppm formaldehyde concentration at an N/L ratio of 0.96. The choice of 0.6 ppm concentration is purely arbitrary. Figure 8 graphically represents the normalized formaldehyde chamber concentrations to loadings at air changes of 0.5, 1.0 and 1.5. The points which define the curves are averages of the normalized concentrations.

After determining a concentration of test compound which elicits no visually detectable response or effect in the aquatic species over a period of 48 hours (Step 1), fresh animals are placed in the chamber, exposed to known concentrations of test chemical (usually 14C-labelled), and the uptake rate and major metabolites determined (Step 2). Depuration rate from the dosed animals also can be estimated at this point by transfer to untreated water. Fresh animals also can be exposed to a constant flow of test solution until an absorption-excretion equilibrium (steady state) has been established, dosed briefly with labelled compound, and release (turnover) rate determined (Step 3). 

OECD has adopted an in vitro test for skin absorption potential (OECD TG 428, Skin Absorption In Vitro Method). According to this guideline, excised skin from human or animal sources can be used. The skin is positioned in a diffusion cell consisting of a donor chamber and a receptor chamber, between the two chambers. The test substance, which may be radio-labeled, is applied to the surface of the skin sample. The chemical remains on the skin for a specified time under specified conditions, before removal by an appropriate cleansing procedure. The fluid in the receptor chamber is sampled at time points throughout the experiment and analyzed for the test chemical and/or metabolites. 

Fig. 4.3. (A) Diagram of the amnion invasion assay. The invasion chamber represents a cylindrical well produced by a Teflon ring (a) to which epithelium-free amnion (b) is fastened with the aid of a viton ring (c), to face the BM side up and stromal side down. A smaller lower chamber is created by a silicone rubber ring support attached to the bottom of a 35-mm tissue culture well (d) with silicone grease, and filled with medium. The (upper) invasion chamber is placed on this support, and medium with or without additives (to be tested for invasion-blocking or stimulating ability) is added to this chamber 1 h prior to the addition of labeled cells to be tested for invasive ability. Medium is then added to the tissue culture well (d) outside these chambers to bring the fiuids inside and outside the Teflon ring to the same level (e) represents a well that includes the complete invasion chamber seeded with cells on the BM. (Reproduced from Yagel et al., 1989.) (B) (a) Human amnion. Epithelium (EP), basement membrane (BM), connective tissue stroma (ST). Haematoxylin-eosin PAS stain, (b) Denuded human amnion membrane. Basement membrane (BM), connective tissue stroma (ST), Milfipore filter (F). Haematoxylin-eosin, PAS stain. (Reproduced from Russo, 1986.)...

Table VIII presents chamber data on underlayment particleboard, mobile decking particleboard, and industrial particleboard obtained from four different chambers identified A, B, C and D. A particleboard "set" is a specific production run of a particleboard type. The observed concentration is the formaldehyde level actually determined in the chamber for a specific loading and air change rate. "N" represents the air change rate (number per hour). The column labeled "L" is the loading (m2/m3) that the test was conducted. The column "N/L" ( m/hr) is the ratio of air change rate to the loading. Finally, the column labeled "Normalized Chamber Concentration" is the actual chamber concentration (first column) normalized to 0.3 ppm at N/L = 1.16. The 0.3 ppm chamber...

Add an excess of enzyme-labeled antigen (established in step 2) to determine the amount of antibody still free after the test sample had the possibility to saturate these antibodies. Incubate for 2 h (optimum time should be established) at room temperature in a humid chamber. 

The heat flux vs, time curves used in the computer runs are shown in Fig. 8. The curves labeled D and E were obtained from heat chamber calibrations described previously. The curves labeled A and B were obtained from calculations of enthalpy gain of the liquid for Tests No. 12 and 1, respectively. Curve C was obtained by interpolation. The peculiar characteristics exhibited by these curves have not been explained. Initially it had been assumed that the heat flux would be essentially constant, but obviously this is not the case. 

The chloroplasts were isolated from 12-day old pea pla-nts grown in a climatic chamber under irradiance 9 and 30 W/m (LL and HL variants) and at 15°C. The isolation medium contained 50 mM trycin buffer, pH 7.5, 0.4 M sucrose and 5 niM MgClo. The chloroplast sediment was resuspended in an isolation medium that contained 0.1 M sucrose used instead of 0.4 M one. The chloroplasts were phosphorylated by incubation in white light (70 W/m ) in the presence of 0.2 mM ATP and 10 mM NaP. The degree of chloroplast protein phosphorylation was tested by radioactive labelling and the spectral methods as described earlier (3) ... 

Before running the column, assemble the following glassware and liquids. Obtain four dry test tubes (16 x 100 mm) and number them 1 through 4.Prepare two dry Pasteur pipettes with bulbs attached. Place 9.0 mL of hexane, 2.0 mL of acetone, and 2.0 mL of a solution of 70% hexane-30% acetone (by volume) into three Erlenmeyer flasks. Clearly label and stopper each flask. Place 0.3 mL of a solution containing fluorene and fluorenone into a small test tube. Stopper the test tube. Prepare one 10 cm x 3.3 cm TLC plate with four marks for spotting. Use the same TLC development chamber with methylene chloride that you used in Part A. Prepare four micropipettes to spot the plates. 

This test is based on the extraction of a fluorescent marker, dansyl chloride, previously bound to the amino groups of proteins inside the full thickness of the stratum comeum [76]. Fluorescent labeling of the skin is performed 1 week prior to the application of the surfactants. When surfactants are applied at 2% of active ingredients and under occlusion, two or three applications of 30 min each are sufficient to detach and extract all or part of the fluorescent dye from the skin in the absence of visible irritation. The level of dansyl chloride extraction has been shown to correlate with the irritation potential of the surfactants as determined in separate soap chamber tests. This test demonstrates that surfactants interact with the skin surface proteins very quickly and are able to release molecules that would be linked to these proteins. The evaluation of fluorescence extraction is done visually by a trained assessor on a 0-4 scale, 0 being no fluorescence extraction and 4 being complete fluorescence extraction. 

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