Mycobacter avium complex serovars 4 and 20 were cultured in the presence of [3H] fucose, [3H]-methionine, and [3H]-mannose to specifically radiolabel the oligosaccharide of the glycopeptidolipid (GPL) antigens. Distribution of radioactivity in lipid was determined by thin-layer chromatographic methods. Examination of acid hydrolysates from radiolabeled antigens revealed that [3H]-methionine incorporated into methylated sugars in polar and apolar GPL components, whereas [3H]-mannose incorporated exclusively into the oligosaccharide of polar GPL antigens. Least incorporation of radiolabel into antigens was observed with [3H]-fucose. Use of radiolabeled serovar 4 antigens in macrophage uptake studies revealed maximum uptake to be slightly above 250 gg/ 3.2 x 105 cells. Timed experiments demonstrated that GPL antigens were relatively inert to degradation by resident peritoneal macrophages.

The purpose of this study is to determine the optimum conditions for obtaining a leukocyte button which most effectively will be subsequently labelled with 111In oxine. As in all radiopharmaceuticals, the highest radiopharmaceutical purity, or the fraction of total radioactivity in the desired radiopharmaceutical form (111In oxine leukocyte), the better the product. Many 111In ocine labelled leukocytes are contaminated by labelled platelets, red cells, and proteins, resulting in a “dirty” product. But with careful leukocyte culturing, sedimentation, centrifugation, and labelling, as demonstrated by this study, a highly desirable, pure radiopharmaceutical can be made. In an attempt to further purify the leukocyte button beyond centrifugation, hypotonic red cell lysing and its effect on leukocyte viability will be studied. The optimum incubation time will be determined by examining the leukocyte and red cell elution profiles at different incubation times. And, 0.9% saline washes of plasma and proteins from the leukocytes will be varied by both volume and number to determine if extra washes will optimize the labelling efficiency.

Strontium (Sr) isotope tracers are useful for understanding provenance and mobility in biological materials across multiple disciplines. However, the impact of these techniques is highly dependent on the construction of appropriate comparative baselines (i.e., an isoscape). We present the results of a systematic survey of87Sr/86Sr values from grasses in the North American Midcontinent with a particular emphasis on sedimentary systems. Although87Sr/86Sr values are highly variable across the region, the Sr isoscape shows ­multi-scalar patterns that are dependent on local-to-regional trends in surficial geology. High values are found in bedrock-dominated areas such as the Black Hills (SD) and Ozark Uplift (MO), or formerly glaciated areas where surface deposits are dominated by ice-transported Precambrian clasts. The lowest values are found in river valleys that incorporate eroded Neogene sediments into terrace formation. Intermediate values are found in upland loess and alluvial deposits which blanket much of the study area. We demonstrate trends in large-scale variability of the Midcontinent’s87Sr/86Sr isoscape and suggest that future refinement focus on sub-regional trends in Sr isotope variability.

Includes bibliographical references. / Atomic diffusion during the solid state formation of thin films of nickel silicides (Ni2Si and NiSi) from nickel and amorphous silicon has been investigated using 31Si radioactive tracer and inert marker techniques. Samples were prepared by vacuum deposition of thin films of nickel and silicon, followed by thermal annealing to effect silicide growth. The radioactive tracer investigation of Ni2Si showed nickel to be the diffusing species during silicide growth. Sharply defined Ni2si* profiles of 100% radioactive concentration at the sample surface were - obtained. The results are compared with previous results in which the profiles were more spread out and of lower surface concentration. The radioactive tracer investigation of NiSi formation showed that nickel is also the diffusing species during second phase growth. The NiSi * layer was found to be of 100% concentration. Some spreading of the activity profile near the NiSi/NiSi* interface was observed. The results were consistent with previous 31Si tracer work on NiSi formation and also with the present Ni * 2Si results. The inert marker investigation used an ultra-thin (5-10 A) continuous layer of Mo or Ta to monitor atomic movement during silicide growth. The results confirmed nickel to be the diffusing species during the growth of both phases. These results are in excellent agreement with previous inert marker studies of nickel silicide growth.

Groundwater is documented to flow through solution-widened fractures and bedding planes in limestone and dolostone units in low-relief topography. This enhancement, or karstification, is much harder to study in alpine environments like the Bear River Range of northern Utah. This is problematic, due to the fact that the Bear River Range karst aquifer system supplies the City of Logan with a large quantity of water at Dewitt Spring. Furthermore, the karst aquifer sustains the Logan River for much of the year, and may allow groundwater to flow directly in the subsurface to the Cache Valley principal aquifer system. Flow measurements along the Logan River constrain a minimum volume of 2.32x106 m3 /y (1.88x103 af/y) that could recharge the Cache Valley principal aquifer. Hydraulic characteristics of alpine karst were estimated by analysis of major ions, stable isotopes, and dissolved gases in spring waters. These data reflect quick groundwater flow through caverns, with no evidence for “diffuse” flow anticipated by some to occupy interstitial space. In fact, the oldest reasonable estimated recharge age for groundwater is 70 years. Young recharge, fast flow, and low storage capability indicate that alpine karst aquifers are very sensitive to droughts and that related water resources are vulnerable to longer-term changes in climate.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography: leaf 186. / by Thomas James Miller, Jr. / M.S.

Groundwater tracing studies have shown a well-developed conduit system in the karst aquifer beneath the Buffalo Creek Watershed of Carter County, TN. Groundwater can quickly travel beneath topographic divides, transporting contaminants. Using GIS and field reconnaissance, two sites were selected for a two phase dye trace study. In May-June 2016 groundwater resurgences were located using activated carbon samplers, and in October-December 2016 flow velocities were measured using ISCO automatic water samplers. In study 1, a stream sinking in the back of Carter Saltpeter Cave was traced to its resurgence at Cave Springs Cave. In study 2, the dye mass centroid passed the resurgence 23.2 hours after injection. During study 1, dye injected into a sinkhole near the headwaters of Toll Branch rapidly diffused into multiple conduits. In study 2, dye from the Toll Branch site was not recovered, indicating that groundwater follows different flow paths dependent on water table level.

No description available.

No description available.

Thesis. 1976. Ph.D.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences. / Microfiche copy available in Archives and Science. / Vita. / Bibliography: leaves 160-165. / Ph.D.