Influence of oxygen pressure on the fs laserinduced oxidation of molybdenum thin films

We present a study of femtosecond (1028 nm, 230 fs, 54.7 MHz) laser processing on molybdenum (Mo) thin films. Irradiations were done under ambient air as well as pure oxygen (O2) at various gauge pressures (4, 8, 12 and 16 psi). Our results indicate that the high heating rates associated with laser processing allow the production of different molybdenum oxides. Raman spectroscopy and scanning electron microscopy are used to characterize the molybdenum oxidation for the different irradiation and oxygen pressures parameters chosen showing a high correlation between well-defined oxidation zones and the oxygen pressure surrounding the samples during the irradiation of the Mo thin films

Lineage Switch Macrophages Can Present Antigen

Recent reports of “lineage switching” from a lymphoid to macrophage phenotype have left unresolved the question of whether such cells are functional macrophages or nonfunctional products of differentiation gone awry. This study demonstrates that several “macrophage-like” cell lines derived from v-Ha-ras-transformed pre-B cells have gained the capacity to effectively present antigen in MHC-restricted fashion. Using an assay involving the cocultivation of putative antigen-presenting cells with chicken ovalbumin (cOVA) and a cOVA-specific T-cell hybridoma, “lineage switch” cell lines were found to present antigen as effectively as macrophage-containing peritoneal exudates. Neither the original pre-B-cell precursors nor B-cell lymphomas derived from them present antigen. Thus, we have demonstrated that these “lineage switch” macrophages are capable of antigen presentation, a mature differentiated function. While gaining macrophage characteristics, these cells have also rearranged their kappa light-chain immunoglobulin locus, suggesting that macrophage differentiation and immunoglobulin rearrangement are not mutually exclusive processes. The existence of both lymphoid and myeloid characteristics in a cell fully capable of antigen presentation suggests greater plasticity in hematopoietic lineage commitment than conventionally thought to be the case

Skunk River Review September 1992, Vol 4

https://openspace.dmacc.edu/skunkriver/1007/thumbnail.jp

Reengineering the Marine Corps rifle range

With no significant changes in the design of rifle ranges in more than 100 years, the current range systems are not keeping pace with technological advancements. The Marine Corps rifle ranges are manpower and material intensive, requiring unit commanders to lose personnel to the training evolution for extended periods of non-productive time. Manual target operation, excessive transition time, and extra duties all contribute to eight to ten hours per day to accomplish one hour of live-fire training per individual Marine. Marines must remain at the range to act as scorekeepers, target makers, and/or target operators when not assigned to shoot. The design and implementation of an automated range system with capabilities specifically designed to operate, score, mark, and maintain targets would reduce the non-productive time a Marine spends on the rifle range. Results from this comparative analysis indicate that the automated range would reduce man-hours by seventy-five percent. Furthermore, the implementation of computer technology will enable instructors and shooters to better analyze each training evolution.http://archive.org/details/reengineeringmar109459310U.S. Marine Corps (U.S.M.C.) author.Approved for public release; distribution is unlimited

Influence of oxygen pressure on the fs laserinduced oxidation of molybdenum thin films

We present a study of femtosecond (1028 nm, 230 fs, 54.7 MHz) laser processing on molybdenum (Mo) thin films. Irradiations were done under ambient air as well as pure oxygen (O2) at various gauge pressures (4, 8, 12 and 16 psi). Our results indicate that the high heating rates associated with laser processing allow the production of different molybdenum oxides. Raman spectroscopy and scanning electron microscopy are used to characterize the molybdenum oxidation for the different irradiation and oxygen pressures parameters chosen showing a high correlation between well-defined oxidation zones and the oxygen pressure surrounding the samples during the irradiation of the Mo thin films