Silicon (Si) nanomaterials with bright luminescence in the visible region are promising materials for use as the nextgeneration light source in displays, lighting, and biomedical imaging. A scalable and cost-effective method for the synthesis of Si quantum dots (SiQDs) is essential for research and development in the field of quantum dots. Herein, we show a facile and costeffective method for controlling the structure and properties of SiQDs, obtained using the pyrolysis of hydrogen silsesquioxane (HSQ) polymer precursors synthesized using methanol. The amount of methanol added to trichlorosilane prior to the addition of water is a key factor that determines the structure and crosslinking density of the HSQ polymer used as the precursor. In turn, these features control the SiQD size, crystallinity, and luminescence efficiency. Dodecyl-passivated SiQDs of size 3−4 nm are obtained as a final product and show red photoluminescence (PL) at approximately 700−800 nm with the peak wavelength depending on the size of SiQDs. The PL quantum yield ranged from 10 to 25% with the highest value obtained for the smaller SiQDs with higher crystallinity. The present study provides new insight into the SiQD synthesis procedure and the understanding of the reaction mechanism. Furthermore, it was found that only methanol is the crucial reagent and the facile and cost-effective synthesis method can be controlled merely by changing the amount of methanol.

Nanomaterial toxicity and environmental concerns inspired us to develop a scalable method for fabricating quantum dots with a positive environmental impact. Milling rice creates billions of kilograms of rice husks yearly, which are an excellent source for high-quality silica (SiO 2 ) and value-added silicon (Si) powders. Herein, we synthesize SiO 2 , porous Si, and Si quantum dots (SiQDs) from rice husks containing 20 wt % SiO 2 using a conventional chemical synthesis method and investigate the structure, optical, and optoelectrical properties. The extraction yields of SiO 2 and Si powders from rice husks are 100 and 86%, respectively. The final product, decyl-passivated SiQDs, consists of 3 nm crystalline particles that are soluble in an organic solvent. A colloidal solution of the decyl-passivated SiQDs exhibits orange− red photoluminescence at a wavelength of 680 nm, with a 21% quantum yield. This colloidal solution is used to develop a SiQD LED, resulting in orange−red electroluminescence.

SUMMARYPre-messenger RNA (pre-mRNA) splicing is essential in eukaryotic cells. In animals and yeasts, the DEAHbox RNA-dependent ATPase Prp16 mediates conformational change of the spliceosome, thereby facilitating pre-mRNA splicing. In yeasts, Prp16 also plays an important role in splicing fidelity. Conversely, PRP16 orthologs in Chlamydomonas reinhardtii and nematode do not have an important role in general pre-mRNA splicing, but are required for gene silencing and sex determination, respectively. Functions of PRP16 orthologs in higher plants have not been described until now. Here we show that the CLUMSY VEIN (CUV) gene encoding the unique Prp16 ortholog in Arabidopsis thaliana facilitates auxin-mediated development including male-gametophyte transmission, apical-basal patterning of embryonic and gynoecium development, stamen development, phyllotactic flower positioning, and vascular development. cuv-1 mutation differentially affects splicing and expression of genes involved in auxin biosynthesis, polar auxin transport, auxin perception and auxin signaling. The cuv-1 mutation does not have an equal influence on pre-mRNA substrates. We propose that Arabidopsis PRP16/CUV differentially facilitates expression of genes, which include genes involved in auxin biosynthesis, transport, perception and signaling, thereby collectively influencing auxin-mediated development.

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Silicon (Si) is a highly abundant, environmentally benign, and durable material and is the most popular semiconductor material; and it is used for the field enhancement of dielectric materials. Porous Si (PSi) exhibits high functionality due to its specific structure. However, the field enhancement of PSi has not been clarified sufficiently. Herein, we present the field enhancement of PSi by the fluorescence intensity enhancement of a dye molecule. The raw material used for producing PSi was rice husk, a biomass material. A nanocoral structure, consisting of spheroidal structures on the surface of PSi, was observed when PSi was subjected to chemical processes and pulsed laser melting, and it demonstrated large field enhancement with an enhancement factor (EF) of up to 545. Confocal microscopy was used for EF mapping of samples before and after laser melting, and the maps were superimposed on nanoscale scanning electron microscope images to highlight the EF effect as a function of microstructure. Nanocoral Si with high EF values were also evaluated by analyzing the porosity from gas adsorption measurements. Nanocoral Si was responsible for the high EF, according to thermodynamic calculations and agreement between experimental and calculation results as determined by Mie scattering theory.