Fail-safe system for activity cooled supersonic and hypersonic aircraft

A fail-safe-system concept was studied as an alternative to a redundant active cooling system for supersonic and hypersonic aircraft which use the heat sink of liquid-hydrogen fuel for cooling the aircraft structure. This concept consists of an abort maneuver by the aircraft and a passive thermal protection system (TPS) for the aircraft skin. The abort manuever provides a low-heat-load descent from normal cruise speed to a lower speed at which cooling is unnecessary, and the passive TPS allows the aircraft skin to absorb the abort heat load without exceeding critical skin temperature. On the basis of results obtained, it appears that this fail-safe-system concept warrants further consideration, inasmuch as a fail-safe system could possibly replace a redundant active cooling system with no increase in weight and would offer other potential advantages

Aerodynamic characteristics at Mach 6 of a hypersonic research airplane concept having a 70 deg swept delta wing

The hypersonic aerodynamic characteristics of an air-launched, delta-wing research aircraft concept were investigated at Mach 6. The effect of various components such as nose shape, wing camber, wing location, center vertical tail, wing tip fins, forward delta wing, engine nacelle, and speed brakes was also studied. Tests were conducted with a 0.021 scale model at a Reynolds number, based on model length, of 10.5 million and over an angel of attack range from -4 deg to 20 deg. Results show that most configurations with a center vertical tail have static longitudinal stability at trim, static directional stability at angles of attack up to 12 deg, and static lateral stability throughout the angle of attack range. Configurations with wing tip fins generally have static longitudinal stability at trim, have lateral stability at angles of attack above 8 deg, and are directionally unstable over the angle of attack range

Murine T-Lymphomas Corresponding to the Immature CD4-8+ Thymocyte Subset

N-methyl-N-nitrosourea induces murine CD4-8+ T-lymphomas that express high levels of J11d and low levels of CD5 antigens, a phenotype characteristic of immature CD4-8+ thymocytes. This assignment is supported by the fact that CD4-8+ lymphoma cell lines acquire CD4 expression after intrathymic (i.t.) transfer, a finding consistent with the established precursor potential of the normal immature CD4-8+ subset. CD4+8+ lymphomas recovered after i.t. transfer maintain a CD4+8+ phenotype in long-term culture. Northern blot analyses reveal that CD4 expression is regulated at the transcriptional level in immature CD4-8+ and CD4+8+ cell lines. CD4-8+ lymphomas express low levels of functional CD3/TCR complexes that mediate intracellular Ca2+ mobilization in response to CD3 or α/β-TCR monoclonal antibody. These data suggest that the immature CD4-8+ subset contains cells capable of undergoing TCR-mediated signaling and selection events. In contrast to normal immature CD4-8+ cells, which comprise a heterogeneous and transient subset, the CD4-8+ lymphoma lines provide stable, monoclonal models of the immature CD4-8+ stage of thymocyte development

Cross-Linking the TCR Complex Induces Apoptosis in CD4+8+ Thymocytes in the Presence of Cyclosporin A

Although it is generally agreed that TCR ligation is a minimal requirement for negative selection in the CD+8+ double-positive (DP) thymocyte subset, the costimulatory requirements and specific signaling events necessary to induce apoptosis are not well defined. We have explored the consequences of cross-linking CD3/TCR complexes on thymocytes from H-Y TCR transgenic (Tg) mice. In agreement with previous reports, we demonstrate that culturing DP thymocytes with plate-bound anti-TCR antibody induces downregulation of CD4 and CD8 and upregulation of CD69 expression. Nevertheless, the activated cells did not undergo apoptosis, as determined by viable cell recoveries and by quantitation of DNA fragmentation using the TUNEL assay. However, specific depletion of the DP subset occurred within 24 hr when thymocytes were incubated in the presence of both anti-TCR and the immunosuppressant cyclosporin A (CsA). CsA also induced depletion of anti-CD3 stimulated normal DP thymocytes. Using mice homozygous for the lpr or gld mutation, we also have shown that Fas/Fas ligand interactions are not involved in the CsA-induced death of TCR-stimulated DP thymocytes. These data verify that TCR cross-linking alone is insufficient to induce apoptosis of DP thymocytes and further suggest that TCR stimulation activates a CsA-sensitive protective pathway that interferes with signaling events leading to apoptosis in DP thymocytes

Project 400: The Plymouth Colony Archaeological Survey, Report on the 2014 Field Season, Burial Hill Plymouth, Massachusetts

In May and June of 2014, a field school from the University of Massachusetts Boston, in partnership with Plimoth Plantation, undertook a second season of work in Plymouth, Massachusetts, as part of Project 400: The Plymouth Colony Archaeological Survey, a site survey and excavation program leading up to the 400th anniversary of New England’s first permanent English settlement in 1620, the founding of Plymouth Colony. This work was conducted under permit #3384 from the State Archaeologist’s office at the Massachusetts Historical Commission. The 2014 work focused on the eastern edge of Burial Hill along School Street in downtown Plymouth and consisted of ground penetrating radar survey and excavation (3 STPs and 9 EUs). Burial Hill, formerly Fort Hill, is understood as the location of the original fort built by the English colonists, and the walls that enclosed the fort and town stretched down the hill towards the harbor. The precise locations of any of these features have never been archaeologically identified. In the 18th and 19th centuries, the land on the eastern edge of the hill along School Street was sold to individuals who built houses and stables, all demolished by the early 20th century. Our test excavations were designed to see if any 17th-century features or deposits existed either under the floors of these buildings or in the strip of land between the backs of the buildings and the burials, which begin roughly 20 meters from the street. During the 2014 season, we did not locate any 17th-century features or deposits. The 2014 excavation units tested the footprints of 4 different 19th-century building lots (an 1827 school and three barn or stable buildings), all of which were demolished between 1882 and 1901. With the exception of the school, the buildings completely filled the 30 foot deep lots that existed along School Street. The excavations revealed that the buildings had been cut into the hill, destroying any earlier deposits that might have existed in those areas. Because of their particular construction and the area topography, there was almost no trash deposition behind the buildings, up the slope of Burial Hill. As each building was taken down, its footprint was filled, first to create a level surface, then to create a regular slope for this edge of Burial Hill. Each building appears to have been filled individually, since the deposits within each building footprint were quite different from each other. Material to fill these substantial building footprints must have been brought in from elsewhere; the slag in EU3 is the clearest evidence of this. Although we found flaked tools (a quartz flake drill, a rhyolite unifacial scraper, and quartz Small Stemmed points) in the topsoil and fill layers of EUs 8 and 9 and chipping debris (quartz and rhyolite) in all excavation units, we found no in-situ Native artifacts or features. With the exception of the large metal pieces in EU2 and some related deposits in EU9 which seem to be primary trash deposits, most other deposits contained either predominantly architectural materials (brick, nails, window glass), or a mixture of architectural materials and redeposited sheet refuse (ceramics and glass in small fragments). One of the only in situ, non-fill deposits that we encountered was the test pit that we dug below the building floor layer of EU2 which uncovered an associated late 18th or early 19th century pipe bowl and a dog skeleton, either a burial or an animal that died below the floor. From other units, there were a number of interesting small finds such as buttons, pins, an 1874 Indian Head penny, and buckles, including an early 20th-century Red Cross pin. Other notable artifacts include fragments of six possible gravestones in both slate and marble. One of these is decorated and appears to be a fragment of a slate Medusa style design from the Soule family of carvers, probably from the 1750s or 1760s. An analysis of all of the bone and tooth fragments recovered during the field season confirmed that the whole collection consisted of the remains of common animals (cat, dog, rat, duck, chicken, sheep/goat, pig, and cow) and included no human remains. EU7, located in the lot that held the 1827 school, yielded a significant collection of small finds related to the school including pen nibs, slate pencils, and a possible compass fragment. The report illustrates these materials and presents comparative research on the archaeology of school sites and artifacts

INSULIN SECRETAGOGUE EFFECT OF ROOTS OF RAVENALA MADAGASCARIENSIS SONN. - AN IN VITRO STUDY

Objective: The objective of this study was to establish the cytotoxicity profile and to evaluate the insulin secretagogue effect of ethanolic root extract of Ravenala madagascariensis Sonn. Methods: The cell viability of rat insulinoma 5F (RIN5F) cell lines over the treatment of plant extract was assessed by 3-(4,5-dimethyl-2-thiazolyl)- 2,5-diphenyltetrazolium bromide assay. The insulin-releasing effect was evaluated by insulin secretion assay over RIN5F cell lines by enzyme-linked immunosorbent assay. Results: The ethanolic extract of the roots of R. madagascariensis Sonn. showed negligible cytotoxicity at 20–40 μg/ml, and hence, concentrations up to 40 μg/ml were used in insulin secretion assay. The ethanolic root extract at 20 and 40 μg/ml significantly (p<0.05 compared to control) stimulated the insulin release in a dose-dependent manner even in the presence of glucose at lower and higher concentrations (5 and 10 mM). Conclusion: Thus, our results validate its traditional claim in the treatment of diabetes by stimulating the secretion of insulin, thereby suggesting a possible mechanism of its antidiabetic effect

Role of polymorphisms in codons 143 and 160 of the O6-alkylguanine DNA alkyltransferase gene in lung cancer risk

O6-Alkylguanine DNA alkyltransferase (AGT) plays an important role in the repair of alkylating agent-induced DNA damage and protection from the carcinogenic effects of environmental agents. To examine the importance of the AGT codon 143 and codon 160 polymorphisms in risk for lung cancer and to assess the prevalence of these polymorphisms in different racial groups, we performed genotype analysis of lung cancer patients and matched controls. The prevalence of the AGT143Val allele in controls was 0.07 in Caucasians and 0.03 in African Americans. The AGT143Val allele was not detected in an unmatched Asian control cohort. The prevalence of the AGT160Arg variant allele was 0.01 in Caucasians, 0.02 in African Americans, and 0.03 in Asians. A marginally significant association was observed between the AGT codon 143 (isoleucine/valine) genotype and risk for lung cancer (odds ratio = 2.1; 95% confidence interval = 1.01– 4.7). The prevalence of the AGT160Arg variant allele was similar in lung cancer cases versus matched controls. These results suggest that the AGT codon 143 polymorphism may play an important role in risk for lung cancer