The control of gene expression is an important tool for metabolic engineering, the design of synthetic gene networks, and protein manufacturing. The most successful approaches to date are based on modulating mRNA synthesis via an inducible coupling to transcriptional effectors. Here we present a biological programming structure that leverages a system of engineered transcription factors and complementary genetic architectures. We use a modular design strategy to create 27 non-natural and non-synonymous transcription factors using the lactose repressor topology as a guide. To direct systems of engineered transcription factors we employ parallel and series genetic (DNA) architectures and confer fundamental and combinatorial logical control over gene expression. Here we achieve AND, OR, NOT, and NOR logical controls in addition to two non-canonical half-AND operations. The basic logical operations and corresponding parallel and series genetic architectures represent the building blocks for subsequent combinatorial programs, which display both digital and analog performance.
The atomic layer deposition (ALD) of ZnS films with Zn(TMHD)2 and in situ generated H2S as precursors was investigated, over a temperature range of 150–375 °C. ALD behavior was confirmed by investigation of growth behavior and saturation curves. The properties of the films were studied with atomic force microscopy, scanning electron microscopy, energy-dispersive x-ray spectroscopy, ultraviolet–visible–infrared spectroscopy, and extended x-ray absorption fine structure. The results demonstrate a film that can penetrate a porous matrix, with a local Zn structure of bulk ZnS, and a band gap between 3.5 and 3.6 eV. The ZnS film was used as a buffer layer in nanostructured PbS quantum dot solar cell devices.
Multilayer film stacks of ZnS and Cu x S (x $ 2) were made via atomic layer deposition. The precursors were bis(2,2,6,6-tetramethyl-3,5-heptanedionato)zinc, bis(2,2,6,6-tetramethyl-3,5heptanedionato)copper, and H 2 S generated in situ for sulfur. Samples were deposited at 200 C, in layers ranging from approximately 2 to 20 nm thick, based on binary growth rates. The properties of the film stacks were studied with atomic force microscopy, ultraviolet-visible spectroscopy, and extended x-ray absorption fine structure. The results demonstrate that the structure of films with the thinnest layers is dominated by Cu x S, whereas in the thicker films, the structure is determined by whichever material is first deposited. This can be attributed to the crystal structure mismatch of ZnS and Cu x S. V
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.