AFRL’s Multi-Satellite Deployment System (MSDS)

One new way to perform missions from space is the concept of clusters of microsatellites that operate cooperatively to perform the function of a larger, single satellite. Each smaller satellite communicates with the others and shares the processing, communications, and payload or mission functions. The Air Force Research Laboratory (AFRL) is exploring this new paradigm for performing space missions in a partnership program with AFOSR, DARPA, STP and GSFC, called the University Nanosatellite program. Through this program, AFRL is sponsoring the development and launch of 9 university designed and built nanosatellites. The universities are pursuing creative low-cost space experiments to explore and demonstrate the usefulness of nanosatellites in such areas as miniature bus technologies, formation flying, enhanced communications, distributed satellite capabilities, and maneuvering. The satellites are planned to launch on two Shuttle flights in early 2003. The knowledge gained from this program will aid other Air Force programs such as TechSat-21. The Air Force Research Laboratory is also contributing to this effort by designing and building a Multi-Satellite Deployment System (MSDS). The MSDS is a platform designed to deploy multiple satellites to low-earth orbit using the Shuttle as the primary launch vehicle. The MSDS consists of an aluminum platform with two mounting locations, each of which can support a stack of one or more Nanosatellites. The MSDS/Nanosatellite system is attached to the Shuttle Hitchhiker Experiment Launch System (SHELS), and the entire assembly is installed in the Shuttle Payload Bay. Contingent on the success of the University Nanosatellite program first flights, the MSDS will be a viable platform for the launch and deployment of future small satellites

University Developed Hardware for the Space Shuttle: Strategies for Success

The current trend in space science is for payload developers to minimize program cost and schedule while conducting useful science. One problem with the design, integration, and testing of lowcost missions is that much of the savings results from the assumption of risk. Analyzing lessons learned from high-risk programs is an effective means for increasing success while meeting budget and schedule constraints. University efforts, such as the University Nanosat Program (UNP), are faced with the seemingly contradictory goals of mission success and low cost while designing revolutionary experiments. Currently planned for a shuttle launch, UNP is subject to rigorous qualification requirements resulting from NASA’s manned spaceflight safety program. Universities have limited experience with the design, integration, and test of flight hardware for manned spaceflight. The program has identified many areas for improvement. This paper explores the effects of various program and technical approaches--those that worked, and those that didn’t. Design, integration and test, configuration management, quality assurance, and safety are considered. Lessons learned from the University Nanosat Program are expected to be the basis for success in launching future university-built technology

The “I” in us, or the eye on us? Regulatory focus, commitment and derogation of an attractive alternative person

When individuals are highly committed to their romantic relationship, they are more likely to engage in pro-relationship maintenance mechanisms. The present research expanded on the notion that commitment redirects self-oriented goals to consider broader relational goals and examined whether commitment interacts with a promotion and prevention focus to activate derogation of attractive alternatives. Three studies used cross-sectional and experimental approaches. Study 1 showed that romantically involved individuals predominantly focused on promotion, but not prevention, reported less initial attraction to an attractive target than single individuals, especially when highly committed to their relationship. Study 2 showed that romantically involved individuals induced in a promotion focus, compared to those in prevention focus, reported less initial attraction, but only when more committed to their relationship. Regardless of regulatory focus manipulation, more committed individuals were also less likely to perceive quality among alternative scenarios and to be attentive to alternative others in general. Finally, Study 3 showed that romantically involved individuals induced in promotion focus and primed with high commitment reported less initial attraction, than those primed with low commitment, or than those induced in prevention focus. Once again, for these latter no differences occurred according to commitment prime. Together, the findings suggest that highly committed promotion focused individuals consider broader relationship goals and activate relationship maintenance behaviors such as derogation of attractive alternatives to promote their relationship

Type 2 diabetes – an autoinflammatory disease driven by metabolic stress

Type 2 diabetes has traditionally been viewed as a metabolic disorder characterised by chronic high glucose levels, insulin resistance, and declining insulin secretion from the pancreas. Modern lifestyle, with abundant nutrient supply and reduced physical activity, has resulted in dramatic increases in the rates of obesity-associated disease conditions, including diabetes. The associated excess of nutrients induces a state of systemic low-grade chronic inflammation that results from production and secretion of inflammatory mediators from the expanded pool of activated adipocytes. Here, we review the mechanisms by which obesity induces adipose tissue dysregulation, detailing the roles of adipose tissue secreted factors and their action upon other cells and tissues central to glucose homeostasis and type 2 diabetes. Furthermore, given the emerging importance of adipokines, cytokines and chemokines in disease progression, we suggest that type 2 diabetes should now be viewed as an autoinflammatory disease, albeit one that is driven by metabolic dysregulation

CGI-58 knockdown sequesters diacylglycerols in lipid droplets/ER-preventing diacylglycerol-mediated hepatic insulin resistance

Comparative gene identification 58 (CGI-58) is a lipid droplet-associated protein that promotes the hydrolysis of triglyceride by activating adipose triglyceride lipase. Loss-of-function mutations in CGI-58 in humans lead to Chanarin-Dorfman syndrome, a condition in which triglyceride accumulates in various tissues, including the skin, liver, muscle, and intestines. Therefore, without adequate CGI-58 expression, lipids are stored rather than used for fuel, signaling intermediates, and membrane biosynthesis. CGI-58 knockdown in mice using antisense oligonucleotide (ASO) treatment also leads to severe hepatic steatosis as well as increased hepatocellular diacylglycerol (DAG) content, a well-documented trigger of insulin resistance. Surprisingly, CGI-58 knockdown mice remain insulin-sensitive, seemingly dissociating DAG from the development of insulin resistance. Therefore, we sought to determine the mechanism responsible for this paradox. Hyperinsulinemic-euglycemic clamp studies reveal that the maintenance of insulin sensitivity with CGI-58 ASO treatment could entirely be attributed to protection from lipid-induced hepatic insulin resistance, despite the apparent lipotoxic conditions. Analysis of the cellular compartmentation of DAG revealed that DAG increased in the membrane fraction of high fat-fed mice, leading to PKCε activation and hepatic insulin resistance. However, DAG increased in lipid droplets or lipid-associated endoplasmic reticulum rather than the membrane of CGI-58 ASO-treated mice, and thus prevented PKCε translocation to the plasma membrane and induction of insulin resistance. Taken together, these results explain the disassociation of hepatic steatosis and DAG accumulation from hepatic insulin resistance in CGI-58 ASO-treated mice, and highlight the importance of intracellular compartmentation of DAG in causing lipotoxicity and hepatic insulin resistance

The role of exotic plants in the invasion of Seychelles by the polyphagous insect Aleurodicus disperses: a phylogenetically controlled analysis

The accidental introduction of the spiralling whitefly, Aleurodicus dispersus Russell (Homoptera: Aleyrodidae) to Seychelles in late 2003 is exploited during early 2005 to study interactions between A. dispersus, native and exotic host plants and their associated arthropod fauna. The numbers of A. dispersus egg spirals and pupae, predator and herbivore taxa were recorded for eight related native/exotic pairs of host plants found on Mahe, the largest island in Seychelles. Our data revealed no significant difference in herbivore density (excluding A. dispersus) between related native and exotic plants, which suggests that the exotic plants do not benefit from 'enemy release'. There were also no differences in predator density, or combined species richness between native and exotic plants. Together these data suggest that 'biotic resistance' to invasion is also unlikely. Despite the apparent lack of differences in community structure significantly fewer A. dispersus egg spirals and pupae were found on the native plants than on the exotic plants. Additional data on A. dispersus density were collected on Cousin Island, a managed nature reserve in which exotic plants are carefully controlled. Significantly higher densities of A. dispersus were observed on Mahe, where exotic plants are abundant, than on Cousin. These data suggest that the rapid invasion of Seychelles by A. dispersus may largely be due to the high proportion of plant species that are both exotic and hosts of A. dispersus; no support was found for either the 'enemy release' or the 'biotic resistance' hypotheses

Thermoresponsive Polymers for Biomedical Applications

Thermoresponsive polymers are a class of “smart” materials that have the ability to respond to a change in temperature; a property that makes them useful materials in a wide range of applications and consequently attracts much scientific interest. This review focuses mainly on the studies published over the last 10 years on the synthesis and use of thermoresponsive polymers for biomedical applications including drug delivery, tissue engineering and gene delivery. A summary of the main applications is given following the different studies on thermoresponsive polymers which are categorized based on their 3-dimensional structure; hydrogels, interpenetrating networks, micelles, crosslinked micelles, polymersomes, films and particles