Chlorella is an attractive organism for complex recombinant protein production because of its eukaryotic characteristics and low cost for large-scale culture. Protoplasts of C. ellipsoidea were transformed with a vector containing the flounder growth hormone gene (fGH) under the control of the cauliflower mosaic virus 35S promoter, and the phleomycin resistance Sh ble gene under the control of the Chlamydomonas RBCS2 gene promoter. The presence of introduced DNA was first determined by PCR amplification of both the fGH and Sh ble genes from genomic DNA isolated from transformants and fGH protein expression was detected by immunoblot analysis. Over 400 microg of fGH protein expression per one liter culture containing 1 x 10(8) cells/ml was estimated by ELISA. Stable integration of introduced DNA was confirmed by Southern blot analysis of genomic DNA digested with restriction enzymes. The introduced DNA and fGH expression were detected after seven successive transfers in media devoid of phleomycin, but stably remained in the presence of the antibiotic. Flounder fry fed on the transformed Chlorella revealed a 25% growth increase after 30 days of feeding.

Artificial synapses based on ferroelectric Schottky barrier field-effect transistors (FE-SBFETs) are experimentally demonstrated. The FE-SBFETs employ single-crystalline NiSi2 contacts with an atomically flat interface to Si and Hf0.5Zr0.5O2 ferroelectric layers on silicon-on-insulator substrates. The ferroelectric polarization switching dynamics gradually modulate the NiSi2/Si Schottky barriers and the potential of the channel, thus programming the device conductance with input voltage pulses. The short-term synaptic plasticity is characterized in terms of excitatory/inhibitory post-synaptic current (EPSC) and paired-pulse facilitation/depression. The EPSC amplitude shows a linear response to the amplitude of the pre-synaptic spike. Very low energy/spike consumption as small as ∼2 fJ is achieved, demonstrating high energy efficiency. Long-term potentiation/depression results show very high endurance and very small cycle-to-cycle variations (∼1%) after 105 pulse measurements. Furthermore, spike-timing-dependent plasticity is also emulated using the gate voltage pulse as the pre-synaptic spike and the drain voltage pulse as the post-synaptic spikes. These findings indicate that FE-SBFET synapses have high potential for future neuromorphic computing applications.

Harvesting the full potential of single crystal semiconductor nanowires (NWs) for advanced nanoscale field-effect transistors (FETs) requires a smart combination of charge control architecture and functional semiconductors. In this article, high performance vertical gate-all-2 around nanowire p-type pFETs are presented. The device concept is based on advanced Ge0.92Sn0.08/Ge group IV epitaxial heterostructures, employing quasi-one-dimensional semiconductor nanowires fabricated with a top-down approach. The advantage of using a heterostructure is the possibility of electronic band engineering with band offsets tunable by changing the semiconductor stoichiometry and elastic strain. The use of a Ge0.92Sn0.08 layer as the source in GeSn/Ge NW pFETs results in a small subthreshold slope of 72 mV/dec and a high ION/IOFF ratio of 3×10 6 . A ~32% drive current enhancement is obtained compared to vertical Ge homojunction NW control devices. More interestingly, the drain-induced-barrier lowering is much smaller with GeSn instead of Ge as the source. The general improvement of the transistor's key figures of merits originates from the valence band offset at the Ge0.92Sn0.08/Ge heterojunction, as well as from a smaller NiGeSn/GeSn contact resistivity.

Vibrio anguillarum, an opportunistic fish pathogen, is the main species responsible for vibriosis, a disease that affects feral and farmed fish and shellfish, and causes considerable economic losses in marine aquaculture. In this study, we used polymerase chain reaction (PCR) to detect V. anguillarum. PCR specificity was evaluated by amplifying the rpoS gene, a general stress regulator, in six strains of V. anguillarum and 36 other bacterial species. PCR amplified a species-specific fragment (689 bp) from V. anguillarum. Furthermore, the PCR assay was sensitive enough to detect rpoS expression from 3 pg of genomic DNA, or from six colony-forming units (CFU) mL(-1) of cultured V. anguillarum. However, the assay was less sensitive when genomic DNA from the infected flounder and prawn was used (limit of detection, 50 ng and 10 ng g(-1) tissue, respectively). These data demonstrate that PCR amplification of the rpoS gene is a sensitive and species-specific method to detect V. anguillarum in practical situations.

No abstract