Telerobotic controller development

To meet NASA's space station's needs and growth, a modular and generic approach to robotic control which provides near-term implementation with low development cost and capability for growth into more autonomous systems was developed. The method uses a vision based robotic controller and compliant hand integrated with the Remote Manipulator System arm on the Orbiter. A description of the hardware and its system integration is presented

Magmatic contributions to hydrothermal systems

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95694/1/eost9233.pd

Optimized design of a low-resistance electrical conductor for the multimegahertz range

We propose a design for a conductive wire composed of several mutually insulated coaxial conducting shells. With the help of numerical optimization, it is possible to obtain electrical resistances significantly lower than those of a heavy-gauge copper wire or litz wire in the 2–20 MHz range. Moreover, much of the reduction in resistance can be achieved for just a few shells; in contrast, litz wire would need to contain ∼ 10[superscript 4] strands to perform comparably in this frequency range

Peripheral T-Cell Lymphoma with Aberrant Expression of CD19, CD20, and CD79a: Case Report and Literature Review

A case of lymphoma of T-cell derivation with aberrant expression of three B-cell lineage markers (CD19, CD20, and CD79a), which was diagnosed on a left axillary excision, is described. Immunohistochemical studies and flow cytometry analysis demonstrated neoplastic cells expressing CD3, CD19, CD20, and CD79a with absence of CD4, CD8, CD10, CD30, CD34, CD56, CD68, TDT, MPO, PAX-5, and surface immunoglobulin. Gene rearrangement studies performed on paraffin blocks demonstrated monoclonal T-cell receptor gamma chain rearrangement with no evidence of clonal heavy chain rearrangement. The neoplastic cells were negative for Epstein-Barr virus (EBV) or Human Herpes Virus 8 (HHV-8). At the time of diagnosis, the PET scan demonstrated hypermetabolic neoplastic cells involving the left axilla, bilateral internal jugular areas, mediastinum, right hilum, bilateral lungs, and spleen. However, bone marrow biopsy performed for hemolytic anemia revealed normocellular bone marrow with trilineage maturation. The patient had no evidence of immunodeficiency or infection with EBV or HHV-8. This is the first reported case of a mature T-cell lymphoma with aberrant expression of three B-cell lineage markers. The current report also highlights the need for molecular gene rearrangement studies to determine the precise lineage of ambiguous neoplastic clones

Peripheral T-Cell Lymphoma with Aberrant Expression of CD19, CD20, and CD79a: Case Report and Literature Review

A case of lymphoma of T-cell derivation with aberrant expression of three B-cell lineage markers (CD19, CD20, and CD79a), which was diagnosed on a left axillary excision, is described. Immunohistochemical studies and flow cytometry analysis demonstrated neoplastic cells expressing CD3, CD19, CD20, and CD79a with absence of CD4, CD8, CD10, CD30, CD34, CD56, CD68, TDT, MPO, PAX-5, and surface immunoglobulin. Gene rearrangement studies performed on paraffin blocks demonstrated monoclonal T-cell receptor gamma chain rearrangement with no evidence of clonal heavy chain rearrangement. The neoplastic cells were negative for Epstein-Barr virus (EBV) or Human Herpes Virus 8 (HHV-8). At the time of diagnosis, the PET scan demonstrated hypermetabolic neoplastic cells involving the left axilla, bilateral internal jugular areas, mediastinum, right hilum, bilateral lungs, and spleen. However, bone marrow biopsy performed for hemolytic anemia revealed normocellular bone marrow with trilineage maturation. The patient had no evidence of immunodeficiency or infection with EBV or HHV-8. This is the first reported case of a mature T-cell lymphoma with aberrant expression of three B-cell lineage markers. The current report also highlights the need for molecular gene rearrangement studies to determine the precise lineage of ambiguous neoplastic clones

Lead isotopic composition of the oldest volcanic rocks of the eastern greater antilles island ARC

Pb isotopic analyses for rocks from the early Cretaceous Los Ranchos Formation, which is the basal volcanic assemblage in the Dominican Republic, fall on a short linear array of shallow slope in a 207Pb/204Pb vs. 206Pb/204Pb plot. The array is interpreted to have formed by decay of local U since the time of ore and rock formation ~ 110 Ma ago. Previously reported analyses of sulfide samples from the Pueblo Viejo Au---Ag deposit in the upper part of the Los Ranchos Formation fall on the lower half of the same linear array. In a 208Pb/204Pb vs. 206Pb/204Pb plot the Los Ranchos Formation can be divided into the lower member with an apparent Th/U ratio of 1.2 and the upper three members with an apparent Th/U ratio of 2.6. A cluster of analyses falls at the least radiogenic end of these arrays and is interpreted to represent the initial Pb isotopic composition of the Los Ranchos magmas. This cluster falls close to the Stacey-Kramers growth curve. For the Los Ranchos Pb, a homogeneous source with [mu]=9.6 and Th/U near 3.8, since 3.7 Ga ago, is implied.Previously reported analyses for correlative rocks of the Water Island Formation, the basal volcanic complex in the Virgin Islands at the east end of the Greater Antilles, suggest a steep linear array extending downwards from the Los Ranchos cluster, after correction of the ratios for U decay since formation of the rocks. This array has a slope of 0.250 +/- 0.023, which could have resulted from magma derivation from sources that had been isolated for ~ 3.0 Ga. Younger rock Pb, from the island of Martinique, has a similar slope, although with larger 206Pb/204Pb and 207Pb/204Pb ratios. The data points extend upward from the radiogenic end of the Los Ranchos array.These relationships indicate a complex derivation of magmas in the area. In the Greater Antilles, the proportion of continental material decreases eastward, while even farther east in the Lesser Antilles at Martinique, the proportion of crustal material, as indicated by Pb isotopic composition, is again very high.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26769/1/0000321.pd

Source of lead in Central American and Caribbean mineralization, II. Lead isotope provinces

In an earlier study of Mesozoic and Cenozoic mineralization in Central America and the Caribbean region, we found that lead isotopic compositions of deposits in northern Central America, which is underlain by a pre-Mesozoic craton, ranged to higher 206Pb/204Pb and 207Pb/204Pb compositions than did deposits from elsewhere in the region, where the basement is Mesozoic oceanic material. Using 16 analyses for 12 new deposits, as well as new analyses for 11 of the samples studied previously, we have found that lead isotopic compositions correlate closely with crustal type but show little or no correlation with depth to the M-discontinuity. The deposits are divisible into three main groups including (in order of increasing 207Pb/204Pb and 208Pb/204Pb ratio): (1) deposits in southern Central America and all deposits in the Greater Antilles except Cuba; (2) all deposits in northern Central America; and (3) the Cuban deposits. Southern Central American and Caribbean lead is higher in 207Pb/204Pb and 208Pb/204Pb than most mid-ocean ridge basalts but could have been derived directly or indirectly from undepleted mantle. Northern Central America can be divided into the Maya block, which belongs to the Americas plate, and the Chortis block, which belongs to the Caribbean plate. Maya block deposits fall along a linear array whereas those of the Chortis block (except the Monte Cristo deposit) form a cluster. These results suggest that the Maya block is underlain by crust or mantle with a large range of U/Pb and Th/U ratios, whereas the Chortis block basement is more homogeneous. Two-stage model calculations indicate an age of about 2280+/-310 m.y. for the Maya block basement, although no such rocks are known in the region. Comparison of the Chortis block data to our recently published lead isotopic analyses of Mexican deposits shows considerable similarities suggesting that the Chortis block could have been derived from Mexico.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24169/1/0000428.pd

Characterizing the recovery of a solid surface after tungsten nano-tendril formation

Recovery of a flat tungsten surface from a nano-tendril surface is attempted through three techniques; a mechanical wipe, a 1673&nbsp;K annealing, and laser-induced thermal transients. Results were determined through SEM imaging and elastic recoil detection to assess the helium content in the surface. The mechanical wipe leaves a ∼0.5&nbsp;μm deep layer of nano-tendrils on the surface post-wipe regardless of the initial nano-tendril layer depth. Laser-induced thermal transients only significantly impact the surface morphology at heat loads of 35.2&nbsp;MJ/m2&nbsp;s1/2 or above, however a fully flat or recovered surface was not achieved for 100 transients at this heat load despite reducing the helium content by a factor of ∼7. A 1673&nbsp;K annealing removes all detectable levels of helium but sub-surface voids/bubbles remain intact. The surface is recovered to a nearly flat state with only some remnants of nano-tendrils re-integrating into the surface remaining.</p