Cobalt- or rhodium-catalyzed synthesis of 1,2-dihydrophosphete oxides C-H activation and formal phosphoryl migration.

A highly stereo- and chemoselective intermolecular coupling of diverse heterocycles with dialkynylphosphine oxides has been realized cobalt/rhodium-catalyzed C-H bond activation. This protocol provides an efficient synthetic entry to functionalized 1,2-dihydrophosphete oxides in excellent yields the merger of C-H bond activation and formal 1,2-migration of the phosphoryl group. Compared with traditional methods of synthesis of 1,2-dihydrophosphetes that predominantly relied on stoichiometric metal reagents, this catalytic system features high efficiency, a relatively short reaction time, atom-economy, and operational simplicity.

Thermal effect analysis on cuboid Pr:YLF crystals pumped by blue laser diodes.

Using blue laser diodes (LDs) to pump Pr:YLF crystals can directly realize visible-band laser output. Compared with the traditional frequency doubling and LD direct output method, it has the advantages of simple design, compact structure, and high beam quality. For solid-state lasers, pump-induced thermal effects of gain media are the principal limiting factors for the desired high-power output.

Up-regulation of circARF3 reduces blood-brain barrier damage in rat subarachnoid hemorrhage model via miR-31-5p/MyD88/NF-κB axis.

Inflammation events have been found to aggravate brain injury and blood-brain barrier (BBB) damage following subarachnoid hemorrhage (SAH). This study probed the role and mechanism of a novel circRNA, circARF3, in regulating the BBB injury in SAH rats and hypoxia-induced vascular endothelial cell (VEC) injury . Levels of circARF3 and miR-31-5p were monitored by RT-PCR.

Copper-Mediated Direct Cyanation of Heteroarene and Arene C-H Bonds by the Combination of Ammonium and DMF.

A copper-mediated cyanation of heteroarene and arene C-H bonds has been developed, where ammonium iodide and DMF served as a safe cyanating combination. This procedure shows a broad substrate scope, allowing the facile access of 2-cyano indole, 1-cyano carbazole, 2-cyano pyrrole, and 2-cyano 1-pyridinyl benzene in high yields with good functional group tolerance.

Rhodium-catalyzed C-H activation/annulation of amidines with 4-diazoisochroman-3-imines toward isochromeno[3,4-c]isoquinolines.

A rhodium-catalyzed C-H activation/annulation of amidines with 4-diazoisochroman-3-imines has been established to afford a series of 8-amino-5H-isochromeno[3,4-c]isoquinolines in moderate to good yields with good functional group tolerance. This reaction proceeded in a sequential C-H activation/carbene migration insertion/intramolecular annulation procedure and featured the construction of a C-C and C-N bond in one pot. UV-vis and fluorescence spectral analyses of these highly fused heteroarenes were performed.

Insight into miRNAs related with glucometabolic disorder.

A microRNA (miRNA) is a single-stranded, small and non-coding RNA molecule that contains 20-25 nucleotides. More than 2000 miRNAs have been identified in human genes since the first miRNA was discovered in Caenorhabditis elegans in the early 1990s. miRNAs play a crucial role in various biological processes by regulating gene expression through post-transcriptional mechanisms.

Efficient isolation and high yield of epidermal cells from foreskin biopsies by dynamic trypsinization.

Cultured keratinocytes play important roles in burn wound healing and scientific research studies. We aimed to modify the isolation method to avoid over-digestion, maximize the number of isolated epidermal cells and establish a more efficient and innocuous way of cell isolation. Compared to the conventional method, the modified method combines the more dynamic process of enzymatic digestion with multiple harvestings of dissociated cells via digestion.

Multiple source frequency-modulated continuous-wave optical reflectometry: theory and experiment.

We propose and demonstrate a novel approach to increase the effective bandwidth of a frequency-modulated continuous-wave (FMCW) ranging system. This is achieved by algorithmically stitching together the swept spectra of separate laser sources. The result is an improvement in the range resolution proportional to the increase in the swept-frequency range.

Multichannel dispersion compensation using a silicon waveguide-based optical phase conjugator.

We experimentally demonstrate dispersion compensation using a silicon-based optical phase conjugator. We achieve simultaneous transmission of four dense wavelength division multiplexing (DWDM) channels spaced at 100 GHz and operating at 10 Gbits/s over 320 km of standard fiber. The measured power penalty at bit error rate of 10(-9) is less than 0.

Raman amplification of 40 Gb/s data in low-loss silicon waveguides.

We demonstrate on-chip Raman amplification of an optical data signal at 40 Gb/s in a silicon-on-insulator p-i-n rib waveguide. Using 230 mW of coupled pump power, on/off gain of up to 2.3 dB is observed, while signal integrity is maintained.

Demonstration of wavelength conversion at 40 Gb/s data rate in silicon waveguides.

We report an efficient wavelength conversion via four-wave-mixing in reverse biased silicon-on-isolator p-i-n rib waveguides and demonstrate, for the first time, the conversion of a high-speed optical pseudo-random bit sequence data at 40 Gb/s. Results give a wavelength conversion efficiency of -8.6dB using a 8cm long waveguide with clear open eye on the wavelength converted signal .

Monolithic integrated Raman silicon laser.

We present a monolithic integrated Raman silicon laser based on silicon-on-insulator (SOI) rib waveguide race-track ring resonator with an integrated p-i-n diode structure. Under reverse biasing, we achieved stable, single mode, continuous-wave (CW) lasing with output power exceeding 30mW and 10% slope efficiency. The laser emission has high spectral purity with a measured side mode suppression exceeding 70dB and laser linewidth of <100 kHz.

Controlling nonlinear processes in microstructured fibers using shaped pulses.

It is possible to modify pulse propagation and nonlinear interactions in microstructured fibers using phase-tailored ultrashort laser pulses. We experimentally investigate how pre-shaping of the input laser pulse can be used to alter its evolution and subsequent output characteristics. We also demonstrate how adaptive pulse shaping can be used to control the output properties of the pulse spectrum.