A modular approach toward extremely large apertures

Modular antenna construction can provide a significant increase in reflector aperture size over deployable reflectors. The modular approach allows reflective mesh surfaces to be supported by a minimum of structure. The kinematics of the selected deployable design approach were validated by the subscale demonstration model. Further design refinements on the module structural/joints and design optimization on intermodule joints are needed

The requirement for designing analyzable space deployable structures

The applied technology satellite parabolic reflector subsystem is one of the first systems designed for space environment with limited terrestrial environmental ability. As a result, the complete performance of the system could not be demonstrated in a terrestrial environment without unacceptable design compromises. This problem was circumvented by developing a test philosophy which relied heavily on analysis to qualify and accept the flight hardware. The test program was successfully concluded and an optimized, low cost structure resulted. It is felt that this test and analysis philosophy can be applied to future space systems, resulting in substantial cost and schedule savings and a mission optimized system

Dynamic stability study for sounding rockets Final report

Joint rotation and compliance, body and fin flexibility, and aerodynamic characteristics effect on roll resonance of sounding rocket

Offset weap rib concept and development

The applicability of the Wrap rib antenna design for offset feed configurations for antennas up to 300 m in diameter was assessed. The antenna design was defined for both symmetric and offset configurations in terms of surface quality, cost, weight, and mechanical complexity. A supporting deployable feed support structure was developed and characterized

The Effects of Different Levels Of Octyl Hydroquinone On The Utilization Of Carotene By The Rat

Substances which prevent polymerization or oxidative reactions from occurring are well known. Such substances have been termed antioxidants or inhibitors . A considerable amount of research has been devoted to the study of these inhibitors of reactions or negative catalysts during the past 30 years. It is pointed out that certain substances susceptible to polymerization or oxidation must be protected. Leather oils, rubber, fats, unsaturated hydrocarbons, aldehydes, and some vitamins and their precursors are substances which are either easily oxidized or are subject to polymerization. Consequently, if their usefulness to man is to be retained they must be protected from oxidative deterioration or polymerization into unwanted substances. Some aromatic amines are known to protect rubber and oils from aging. The polymerization of acrolein may be diminished by the addition of small quantities of resorcinol or other phenolic substances. Tetraethyl lead prevents the oxidation of benzaldehyde in motor fuels, and vitamin S is a well-known antioxygenic substance for fats. Much of the research done on antioxidants has been in the test tube with homogeneous systems. However, in biological systems one is not dealing with homogeneous conditions, thus the study of biological antioxidants becomes complicated. In addition, most metabolic processes cannot be controlled in living organisms as one may regulate the temperature of a test tube reaction, or control the concentration of the reacting substances therein. It has been demonstrated in the test tube that antioxidants can function by breaking chain reactions involving free radicals and by being reversibly oxidized and reduced very easily. Some evidence seems to point to these phenomena taking place with biological antioxidants. The question of how biological antioxidants function in living organisms remains unanswered

Liver-specific activation of AMPK prevents steatosis on a high fructose diet

AMP-activated protein kinase (AMPK) plays a key role in integrating metabolic pathways in response to energy demand. We identified a mutation in the γ1 subunit (γ1D316A) that leads to activation of AMPK. We generated mice with this mutation to study the effect of chronic liver-specific activation of AMPK in vivo. Primary hepatocytes isolated from these mice have reduced gluconeogenesis and fatty acid synthesis, but there is no effect on fatty acid oxidation compared to cells from wild-type mice. Liver-specific activation of AMPK decreases lipogenesis in vivo and completely protects against hepatic steatosis when mice are fed a high-fructose diet. Our findings demonstrate that liver-specific activation of AMPK is sufficient to protect against hepatic triglyceride accumulation, a hallmark of non-alcoholic fatty liver disease (NAFLD). These results emphasize the clinical relevance of activating AMPK in the liver to combat NAFLD and potentially other associated complications (e.g., cirrhosis and hepatocellular carcinoma)

Suppression of Raf-1 kinase activity and MAP kinase signalling by RKIP

Raf-1 phosphorylates and activates MEK-1, a kinase that activates the extracellular signal regulated kinases (ERK). This kinase cascade controls the proliferation and differentiation of different cell types. Here we describe a Raf-1-interacting protein, isolated using a yeast two-hybrid screen. This protein inhibits the phosphorylation and activation of MEK by Raf-1 and is designated RKIP (Raf kinase inhibitor protein). In vitro, RKIP binds to Raf-1, MEK and ERK, but not to Ras. RKIP co-immunoprecipitates with Raf-1 and MEK from cell lysates and colocalizes with Raf-1 when examined by confocal microscopy. RKIP is not a substrate for Raf-1 or MEK, but competitively disrupts the interaction between these kinases. RKIP overexpression interferes with the activation of MEK and ERK, induction of AP-1-dependent reporter genes and transformation elicited by an oncogenically activated Raf-1 kinase. Downregulation of endogenous RKIP by expression of antisense RNA or antibody microinjection induces the activation of MEK-, ERK- and AP-1-dependent transcription. RKIP represents a new class of protein-kinase-inhibitor protein that regulates the activity of the Raf/MEK/ERK modul