Detection of small targets in the infrared: an infrared search and track tutorial.

Airborne target detection in the infrared has been classically known as infrared search and track or IRST. From a military point of view, it can be described as target detection at long ranges where the target image is subpixel in size. Here, the target is "unresolved." It can also describe the detection of aircraft near the observer using distributed apertures in a spherical detection field. From a commercial point of view, an important application is drone detection near live airport operations. As drones become more common, the dual-use functionality of IRST systems is expanding. Technology improvements for IRST systems include the wide proliferation of infrared staring focal planes. New readout integrated circuits allow for time-delay-integration of large format detectors. Stare-step sensors in the future appear to be as common as gimbal-scanned thermal imagers. Detection probability analysis and IRST sensor design is different than targeting system design. We provide a tutorial here on IRST system calculations as well as discussions on broadband versus spectral calculations and new technology considerations.

Immunological response to (1,4)-alpha-D-glucan in the lung and spleen of endotoxin-stimulated juvenile rats.

We investigated the effects of (1,4)-alpha-D-glucan (alpha-DG), a novel immune stimulatory drug from Tinospora cordifolia, on the concentration of pro- and anti-inflammatory cytokines (interleukin [IL]-1beta, IL-6, tumour necrosis factor-alpha [TNF-alpha], gamma-interferon [IFN-gamma] and IL-10) in the lung and spleen of endotoxin-stimulated juvenile rats. Experimental groups (n = 16/group) included controls with an intraperitoneal injection of saline, endotoxaemic rats with a non-lethal dose of 10 mg/kg Escherichia coli endotoxin, and endotoxaemic rats treated with two doses of 10 mg/kg alpha-DG, intraperitoneally, 2 and 4 hr after endotoxin injection. At 24 hr of treatment, rats were euthanized and lungs and spleen were removed for cytokines determination and lung injury. Endotoxaemia increased IL-1beta concentration by fivefold in both organs, while creating a moderate pulmonary hypercellularity (demonstrated by about 11% increase in the alveolar-septal thickening and 11% decrease in the alveolar-interstitial space ratio). In the lung, alpha-DG treatment reduced concentrations of IL-1beta by 30% (p > 0.05), IL-6 by 43% (p < 0.01), IFN-gamma by 46% (p < 0.01) and the anti-inflammatory cytokine, IL-10, by 31% (p > 0.05) compared to endotoxaemia. In the spleen, alpha-DG treatment decreased the ratio of IL-1beta to IL-10 by 55% (p < 0.05), demonstrating an anti-inflammatory trend. These data suggest that alpha-DG differentially modulates cytokine response in the lung and spleen and modifies the pro- and anti-inflammatory balance during an early period of endotoxaemia in juvenile rats.