Vibrio cholerae O1 isolates collected during cholera outbreaks occurring from late 2007 to early 2008 in northern Vietnam were revealed to represent an altered strain containing the RS1 element followed by a CTX prophage harboring El Tor type rstR and classical ctxB on the large chromosome.
We presented an alternative design of type II superlattice photodiodes with the insertion of a mid-wavelength infrared M-structure AlSb∕GaSb∕InAs∕GaSb∕AlSb superlattice for the reduction of dark current. The M-structure superlattice has a larger carrier effective mass and a greater band discontinuity as compared to the standard type II superlattices at the valence band. It acts as an effective medium that weakens the diffusion and tunneling transport at the depletion region. As a result, a 10.5μm cutoff type II superlattice with 500nm M-superlattice barrier exhibited a R0A of 200Ωcm2 at 77K, approximately one order of magnitude higher than the design without the barrier. The quantum efficiency of such structures does not show dependence on either barrier thickness or applied bias.
It has been over 200 years since people recognized the presence of infrared radiation, and developed methods to capture this signal. However, current material systems and technologies for infrared detections have not met the increasing demand for high performance infrared detectors/cameras, with each system having intrinsic drawbacks. Type-II InAs/GaSb superlattice has been recently considered as a promising candidate for the next generation of infrared detection and imaging. Type-II superlattice is a man-made crystal structure, consisting of multiple quantum wells placed next to each other in a controlled way such that adjacent quantum wells can interact. The interaction between multiple quantum wells offers an additional degree of freedom in tailoring the material's properties. Another advantage of type-II superlattice is the experimental benefit of inheriting previous research on material synthesis and device fabrication of bulk semiconductors. It is the combination of these two unique strengths of type-II superlattice--novel physics and easy manipulation--that has enabled unprecedented progress in recent years. In this review, we will describe historical development, and current status of type-II InAs/GaSb superlattice for advanced detection and imaging in the mid-infrared regime (λ = 3-5 µm).
In recent years, constant developments in Internet of Things (IoT) generate large amounts of data, which put pressure on Cloud computing’s infrastructure. The proposed Fog computing architecture is considered the next generation of Cloud Computing for meeting the requirements posed by the device network of IoT. One of the obstacles of Fog Computing is distribution of computing resources to minimize completion time and operating cost. The following study introduces a new approach to optimize task scheduling problem for Bag-of-Tasks applications in Cloud–Fog environment in terms of execution time and operating costs. The proposed algorithm named TCaS was tested on 11 datasets varying in size. The experimental results show an improvement of 15.11% compared to the Bee Life Algorithm (BLA) and 11.04% compared to Modified Particle Swarm Optimization (MPSO), while achieving balance between completing time and operating cost.
Atypical Vibrio cholerae O1 strains -hybrid strains (strains that cannot be classified either as El Tor or classical biotype) and altered strains (El Tor biotype strains that produce classical cholera toxin) -are currently prevalent in Asia and Africa. A total of 74 hybrid and altered strains that harboured classical cholera toxin were investigated by multilocus variable-number tandem repeat analysis (MLVA). The results showed that the hybrid/altered strains could be categorized into three groups and that they were distant from the El Tor strain responsible for the seventh cholera pandemic. Hybrid/altered strains with a tandem repeat of the classical CTX prophage on the small chromosome were divided into two MLVA groups (group I: Mozambique/Bangladesh group; group III: Vietnam group), and altered strains with the RS1-CTX prophage containing the El Tor type rstR and classical ctxB on the large chromosome were placed in two MLVA groups (group II: India/Bangladesh group; group III: India/Vietnam group).
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