Avionics for a Small Satellite

This paper discusses a small. seven and a half (7.5) inch diameter. satellite that NASA-JSC is developing as a technology demonstrator for an astronaut assistant free flyer. The Free Flyer is designed to off load flight crew work load by performing inspections of the exterior of Space Shuttle or International Space Station. The Free Flyer is designed to be operated by the flight crew thereby reducing the number of Extra Vehicle Activities (EVA) or by an astronaut on the ground further reducing crew work load. The paper focuses on the design constraint of a small satellite and the technology approach used to achieve the set of high performance requirements specified for the Free Flyer. Particular attention is paid to the processor card as it is the heart and system integration point of the Free Flyer

An ECF-type transporter scavenges heme to overcome iron-limitation in Staphylococcus lugdunensis

Energy-coupling factor type transporters (ECF) represent trace nutrient acquisition systems. Substrate binding components of ECF-transporters are membrane proteins with extraordinary affinity, allowing them to scavenge trace amounts of ligand. A number of molecules have been described as substrates of ECF-transporters, but an involvement in iron-acquisition is unknown. Host-induced iron limitation during infection represents an effective mechanism to limit bacterial proliferation. We identified the iron-regulated ECF-transporter Lha in the opportunistic bacterial pathogen Staphylococcus lugdunensis and show that the transporter is specific for heme. The recombinant substrate-specific subunit LhaS accepted heme from diverse host-derived hemoproteins. Using isogenic mutants and recombinant expression of Lha, we demonstrate that its function is independent of the canonical heme acquisition system Isd and allows proliferation on human cells as sources of nutrient iron. Our findings reveal a unique strategy of nutritional heme acquisition and provide the first example of an ECF-transporter involved in overcoming host-induced nutritional limitation

Epidemiologic Aspects of an Emerging Focus of Visceral Leishmaniasis in Tbilisi, Georgia

Visceral leishmaniasis (VL) has emerged as a public health problem in Tbilisi, the capital of Georgia. Dogs are the main infection reservoirs for transmission by sand flies of Leishmania infantum to humans, many of whom may become infected without developing disease. Since majority of cases are in children we were interested to know the rate of infection in children and in dogs living within the area where cases of VL have been found, and what factors may affect the risk of infection. Using a test that detects the presence of antibodies in blood as a marker of infection, 7.3% of 4,250 children examined were positive at the baseline survey, and 6% became positive after one year. Overall, 18.2% of domestic and 15.3% of stray dogs were seropositive. The infected children were more apt to live in areas where clustered flying insects and stray dogs were observed, and were far more likely to have experienced a persistent fever in the 6 months before the survey. We conclude that there is very active transmission of L. infantum to both humans and dogs in Tbilisi, and that children remain at high risk of developing clinical disease and sub-clinical infection

Small-molecule inhibitor starting points learned from protein–protein interaction inhibitor structure

Motivation: Protein–protein interactions (PPIs) are a promising, but challenging target for pharmaceutical intervention. One approach for addressing these difficult targets is the rational design of small-molecule inhibitors that mimic the chemical and physical properties of small clusters of key residues at the protein–protein interface. The identification of appropriate clusters of interface residues provides starting points for inhibitor design and supports an overall assessment of the susceptibility of PPIs to small-molecule inhibition

Miniature Robotic Spacecraft for Inspecting Other Spacecraft

A report discusses the Miniature Autonomous Extravehicular Robotic Camera (Mini AERCam)-- a compact robotic spacecraft intended to be released from a larger spacecraft for exterior visual inspection of the larger spacecraft. The Mini AERCam is a successor to the AERCam Sprint -- a prior miniature robotic inspection spacecraft that was demonstrated in a space-shuttle flight experiment in 1997. The prototype of the Mini AERCam is a demonstration unit having approximately the form and function of a flight system. The Mini AERCam is approximately spherical with a diameter of about 7.5 in. (.19 cm) and a weight of about 10 lb (.4.5 kg), yet it has significant additional capabilities, relative to the 14-in. (36-cm), 35-lb (16-kg) AERCam Sprint. The Mini AERCam includes miniaturized avionics, instrumentation, communications, navigation, imaging, power, and propulsion subsystems, including two digital video cameras and a high-resolution still camera. The Mini AERCam is designed for either remote piloting or supervised autonomous operations, including station keeping and point-to-point maneuvering. The prototype has been tested on an air-bearing table and in a hardware-in-the-loop orbital simulation of the dynamics of maneuvering in proximity to the International Space Station

Using geoarchaeological deposit modelling as a framework for archaeological evaluation and mitigation in alluvial environments

The pace of anthropogenic development on floodplains and adjacent valley floors is still increasing and in many countries this is accompanied by a requirement for heritage mitigation and management. The result is an increased demand for effective and efficient archaeological evaluation and mitigation strategies, which can only be achieved in alluvial environments through the application of geoarchaeological methods. This paper uses lidar data combined with deep geophysical survey (electrical resistivity), gouge coring and limited borehole data to derive a three dimensional geoarchaeological deposit model, which provided a vehicle for archaeological evaluation and mitigation. Significantly, the results of this deposit model are compared to the results from the subsequent archaeological evaluation trenching, a methodological next step that has not received sufficient attention within the (geo)archaeological literature. The deposit model is refined using radiocarbon dating and artefactual evidence derived from the archaeological evaluation trenching. The results demonstrate how geoarchaeological deposit modelling can be integrated with archaeological evaluation trenching and provides discussion of the importance and difficulties of integrating geoarchaeological sediment units (archives) with archaeological contextual excavation data, with conventional stratigraphic matrices