Where unconsolidated overburden exceeds 20 m in thickness, the reflection method may be efficiently used with a 12‐channel engineering seismograph to map topography on the overburden‐bedrock interface as well as possible structure within the overburden. The two techniques we suggest are the simplest forms of reflection profiling which can be applied with a minimum amount of equipment which we suggest is a 12‐channel enhancement seismograph, a 12‐geophone array, and a hammer source. These techniques require good transmission characteristics of the overburden as well as a sharp velocity discontinuity at the overburden‐bedrock interface. For data processing and display a microcomputer is essential.

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Epithelial cells of 99% purity and 92% viability were isolated from human tracheas obtained post mortem, and the cellular pathways for lipoxygenation of arachidonic acid were examined in vitro. The (3). Tracheaswere first rinsed with 200 ml of a balanced salt solution consisting of 118.5 mM NaCi, 4.7 mM KCl, 1.2 mM KH2PO4, 24.9 mM NaHCO3, 11.0 mM glucose, 105 units of penicillin per liter, 100 mg of streptomycin per liter, and 100 mg of gentamicin per liter, that was equilibrated with 95% 02/5% CO2 at 25TC. The washed tracheal epithelium was stripped off the underlying lamina propria and minced coarsely, and the fragments were suspended in a solution with the same composition, but also containing 0.02% type I collagenase and 5 mM dithiothreitol. The suspension was agitated at 370C under 95% 02/5% CO2 for up to 60 min. At 30 and 60 min, the fluid phase was decanted into centrifuge tubes, and the dissociated cells were collected by centrifugation for 3 min at 150 x g. The cell pellets were temporarily resuspended in 25-50 ml of a mixture of 50% Dulbecco's modified Eagle's medium (1 g ofglucose per liter) and 50% Ham's nutrient F12 medium containing the same antibiotics and then treated with 144 mM NH4Cl buffered with 17 mM Tris-HCl, pH 7.2, for 2 min at 250C to lyse erythrocytes (4). The epithelial cells were washed and resuspended at a concentration of 4 X 106/ml in Hanks' balanced salt solution containing 25 mM Hepes and the same antibiotics (pH 7.4).Aliquots of the cell suspension were used to assess yield and viability and to characterize morphology. Cell counts and viability were determined by using a hemocytometer and the vital dye erythrosin B. For examination by light microscopy, cells were sedimented onto glass slides by using a cytocentrifuge (Shandon, Sewickly, PA) and stained with Wright-Giemsa. For examination by electron microscopy, cell pellets were fixed with a solution of 2.5% (wt/vol) glutaraldehyde, 80 mM sodium cacodylate, 5 mM CaCl2, and 1% sucrose (pH 7.4). After 12-24 hr, this fixative was replaced with 1.5% OS04 in 30 mM Veronal acetate, pH 7.4, for 2 hr. The fixed cell pellets were rinsed in 25 mM sodium hydrogen maleate (pH 6.0), stained en bloc with uranyl acetate (1.5% in 25 mM sodium hydrogen maleate, pH 5.2) for 90 min at 40C in the dark, dehydrated in ethanol, and embedded in Epon 812. Thin sections with a silver interference color were cut, mounted on copper slot grids coated with Formvar resin (Fullam, Schenectady, NY), and then stained with uranyl acetate (2.5% in 40% methanol) and lead citrate before examination in a JEOL 100S electron microscope.

Recent field tests illustrate the accuracy and consistency of estimating near-surface shear (S) wave velocities calculated using Multi-channel Analysis of Surface Wave (MASW). To evaluate the technique in a variety of near-surface conditions and through a wide range of velocities, MASW-derived S-wave velocity profiles (S-wave velocity vs. depth) were statistically compared to S-wave velocity profiles measured in seven boreholes in the unconsolidated sediments of the Fraser River delta, near Vancouver, B.C., Canada. An overall difference of approximately 15 percent was observed between these two uniquely determined sets of S-wave velocities from the seven well locations. A blind test of the standalone accuracy of MASW was conducted at an eighth well. For this blind test, S-wave velocity measurements made in and interpreted from the borehole were not made available during MASW data processing. Differences between S-wave velocities using MASW from those measured in the blind test borehole averaged nine percent. No systematic differences between these results were observed in data from any of the eight test sites. The MASW method provided reliable S-wave velocity profiles from [Formula: see text] below the ground surface at some sites in the Fraser delta.