Room temperature operation of germanium-silicon single-photon avalanche diode.

The ability to detect single photons has led to the advancement of numerous research fields1-11. Although various types of single-photon detector have been developed12, because of two main factors-that is, (1) the need for operating at cryogenic temperature13,14 and (2) the incompatibility with complementary metal-oxide-semiconductor (CMOS) fabrication processes15,16-so far, to our knowledge, only Si-based single-photon avalanche diode (SPAD)17,18 has gained mainstream success and has been used in consumer electronics. With the growing demand to shift the operation wavelength from near-infrared to short-wavelength infrared (SWIR) for better safety and performance19-21, an alternative solution is required because Si has negligible optical absorption for wavelengths beyond 1 µm. Here we report a CMOS-compatible, high-performing germanium-silicon SPAD operated at room temperature, featuring a noise-equivalent power improvement over the previous Ge-based SPADs22-28 by 2-3.5 orders of magnitude. Key parameters such as dark count rate, single-photon detection probability at 1,310 nm, timing jitter, after-pulsing characteristic time and after-pulsing probability are, respectively, measured as 19 kHz µm-2, 12%, 188 ps, ~90 ns and <1%, with a low breakdown voltage of 10.26 V and a small excess bias of 0.75 V. Three-dimensional point-cloud images are captured with direct time-of-flight technique as proof of concept. This work paves the way towards using single-photon-sensitive SWIR sensors, imagers and photonic integrated circuits in everyday life.

EchoNavigator virtual marker and Agilis NxT steerable introducer facilitate transseptal transcatheter closure of mitral paravalvular leak.

BACKGROUND: Paravalvular leak (PVL), also known as paravalvular prosthetic regurgitation, is not a rare complication after surgical valve replacement, and it may cause varying degrees of heart failure. The transcatheter closure of PVL is technically demanding and challenging. CASE SUMMARY: A 68-year-old man presented with degenerative mitral regurgitation with heart failure, New York Heart Association functional class 3. He received bioprosthetic mitral valve replacement in December 2019. PVL was noted at the location of the aorto-mitral curtain in transesophageal echocardiography without signs of endocarditis or dehiscence of the bioprosthetic valve. Transseptal transcatheter closure of the mitral PVL was performed efficiently using the EchoNavigator virtual marker and Agilis NxT steerable introducer. CONCLUSION: This case highlights that the EchoNavigator virtual marker and Agilis NxT steerable introducer can facilitate transseptal transcatheter closure of mitral PVL by reducing the procedure time and contrast media.

Synthesis and in vitro antitumor activities of novel benzyl urea analogues of sorafenib / 药学学报

A novel series of benzyl urea analogues based on the structural modification of sorafenib were synthesized. Their in vitro antitumor activities against MX-1, HepG2, Ketr3 and HT-29 were evaluated using the standard MTT assay. While several target compounds showed inhibitory activity against multiple cancer cell lines, compound 9 was of particular interest, demonstrating IC50 values (5.69-13.6 micromol x L(-1)) comparable to those of sorafenib. Furthermore, compounds 20 and 23 showed more potent inhibitory activity against HT-29 and MX-1 when compared to sorafenib. In particular, compound 20 bearing the N-3-pyridyl moiety not only exhibited greater inhibitory activity against HT-29 cell line (IC50 3.82 micromol x L(-1)), but also had improved solubility at pH 7.2, is worthy of further investigation as a lead to identify novel antitumor agents.