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Infrared detector technologies engineered from III-V semiconductors such as strained-layer superlattice, quantum well infrared photodetectors, and quantum dot infrared photodetectors provide additional flexibility to engineer bandgap or spectral response cut-offs compared to the historical high-performance detector technology of mercury/cadmium/telluride. The choice of detector cut-off depends upon the sensing application for which the system engineer is attempting to maximize performance within an expected ensemble of operational scenarios that define objects or targets to be detected against specific environmental backgrounds and atmospheric conditions. Sensor performance is typically characterised via one or more metrics that can be modelled or measured experimentally. In this paper, the authors will explore the impact of detector cut-off wavelength with respect to different performance metrics such as noise equivalent temperature difference and expected target detection or identification ranges using analytical models developed for several representative sensing applications encompassing a variety of terrestrial atmospheric conditions in the mid-wave and long-wave infrared wavelength bands. The authors will also report on their review of recently published literature concerning the relationships between cut-off wavelength and the other detector performance characteristics such as quantum efficiency or dark current for a variety of detector technologies. [ABSTRACT FROM AUTHOR]

In the past 30 years, there have been significant advances in the development of modeling and simulation algorithms for electromagnetic railguns. The development of instrumentation capable of measuring the physical parameters that occur during a high-velocity launch, however, has not kept pace with the advances in modeling capabilities. In addition, there has been an increase in the size and complexity of existing railguns, and therefore it has become necessary to find instrumentation that has the flexibility to conform to the variations present from one railgun to the next, to aid in the cross-utilization of instrumentation across the community. This paper will describe results from Georgia Tech and U.S. Navy to evaluate diagnostic techniques that measure different phenomena at higher resolution in both time and space in order to provide the data needed to validate railgun models. The diagnostics described here address all aspects of railgun testing, including the launcher, projectile, and pulsed power supplies and all phases of the evaluation process from validation of modeling and simulation tools to structural health monitoring. Specific quantities for which diagnostics will be described include temperature, electric and magnetic field sensors, and strain measurements. Examples of electromagnetic sensors that will be presented include colossal magnetoresistance sensors, which respond to changes in a magnetic field with a change in resistance, and a slab-coupled optical sensor for detecting electric fields. Test results from railguns at both Georgia Tech and the French-German Institute in Saint-Louis will be described. [ABSTRACT FROM PUBLISHER]

The author reflects on the challenges they faced as a professional optometrists, transitioning from student to doctor. She recalls her days as student who always relies on her mentors to help her in decision making. The changes in the personal and professional characters of students as they stay longer in the optometry school is discusses.

Escherichia coli is a widely used host for the heterologous expression of proteins of therapeutic and commercial interest. The scale and speed at which it can be cultured can result in the rapid generation of large quantities of product. However, to achieve low costs of production a simple and robust purification process is also required. The general factors that impact on the cost of a purification process are the scale at which a process can be performed, the cost of the purification matrix, and the number and complexity of the chromatographic steps employed. Purification of Fab′ fragments of antibodies from the periplasm of E. coli using ion exchange chromatography can result in the co-purification of E. coli host proteins having similar functional pI: such as the periplasmic phosphate binding protein, PhoS/PstS. In such circumstances, an additional chromatographic step is required to separate Fab′ from PhoS. Here, we change the functional pI of the chromosomally encoded PhoS/PstS to effect its non-purification with Fab′ fragments, enabling the removal of an entire chromatographic step. This exemplifies the strategy of the modification of host proteins with the aim of simplifying the production of heterologous proteins. [Copyright &y& Elsevier]