Mechanism of high photoluminescence quantum yield of melem.

To produce high-efficiency organic light-emitting diodes, materials that exhibit thermally activated delayed fluorescence (TADF) are attracting attention as alternatives to phosphorescent materials containing heavy metallic elements. Melem, a small molecule with a heptazine backbone composed only of nitrogen, carbon, and hydrogen, is known to emit light in the near-ultraviolet region and exhibit high photoluminescence (PL) quantum yield and delayed fluorescence. However, the mechanism underlying the high PL quantum yield remains unclear.

Growth and characterization of melem hydrate crystals with a hydrogen-bonded heptazine framework.

In carbon nitride (CN) compounds, hydrogen bonds play a major role in cohesion, in addition to dispersion forces. The crystal structures of CN compounds produced thermal polymerization are complex, but they possess unique and attractive features. Melem is a well-known building unit of CN compounds such as melon and g-CN, which have recently attracted attention as photocatalysts.

Directly modulated optical negative feedback lasers for long-range FMCW LiDAR.

Frequency sweep operation of directly modulated optical negative feedback lasers is numerically and experimentally investigated for frequency-modulated continuous-wave (FMCW) light detection and ranging (LiDAR) with a high signal-to-noise ratio (SNR), particularly over a long range. Low FM noise corresponding to a spectral linewidth of ∼2.0 kHz is sustained even with injection current modulation of an optical negative feedback laser through optical feedback from a Fabry-Perot etalon, and a beat note spectrum with a 30-dB SNR is achieved even when a 300-m delay fiber is used as a ranging sample.

Trans-splicing as a novel method to rapidly produce antibody fusion proteins.

To cultivate the use of trans-splicing as a novel means to rapidly express various antibody fusion proteins, we tried to express antibody-reporter enzyme fusions in a COS-1 co-transfection model. When a vector designed to induce trans-splicing with IgH pre-mRNA was co-transfected with a vector encoding the mouse IgM locus, the expression of V(H)-secreted human placental alkaline phosphatase (SEAP) as well as Fab-SEAP were successfully expressed both in mRNA and protein levels. Especially, the vectors encoding complementary sequence to Smu as a binding domain was accurate and efficient, producing trans-spliced mRNA of up to 2% of cis-spliced one.