Anion-Exchange Blue Perovskite Quantum Dots for Efficient Light-Emitting Devices.

In this study, blue perovskite quantum dots (PQDs) were prepared using didodecyldimethylammonium bromide (DDAB), which can passivate surface defects caused by the loss of surface ligands and reduce particle size distribution. After the passivation of DDAB, blue CsPbClxBr3-x PQDs dispersed in n-octane produced a more compact and uniform PQD thin film than the non-passivated ones. The resulting device showed a stabile lifetime, and an EL peak of 470 nm and a maximum EQE of 1.63% were obtained at an operating voltage of 2.6 V and a current density of 0.34 mA/cm2. This work aims to provide a simple method to prepare blue-emitting PQDs and high-performance PQD-based light-emitting devices.

Sonographic diagnosis of a subclinical wandering spleen: role of the decubitus position.

A wandering spleen is a rare condition. It is usually diagnosed when abdominal pain develops secondary to splenic torsion. Although splenic hypermobility is the pathognomonic feature of a wandering spleen, it is rarely revealed by imaging in the subclinical stage. We report 3 patients with a subclinical wandering spleen who had incidental sonographic findings of splenomegaly. Gray scale and color Doppler sonography in the right decubitus position can easily show the migratory nature and perfusion status of a wandering spleen in real time.

Color Doppler twinkling artifact of calcified cardiac valves in vitro: a not well known phenomenon in echocardiography.

The color Doppler twinkling artifact manifests as a rapidly changing mixture of red and blue colors behind strongly reflective structures. The twinkling artifact occurs behind diseased cardiac valves, although the phenomenon is not well described. This study sought to determine the presence of the color Doppler twinkling artifact in calcified cardiac valves in vitro using soft tissue radiography for reference. Seventeen specimens of diseased cardiac valves from patients undergoing valve replacement surgery were studied. The overall sensitivity and specificity for the detection of calcifications using the presence of the twinkling artifact were 66.7% and 81.8%, respectively. If valves with only microcalcifications or smooth calcifications were eliminated from the analysis, all (100%) of the three valves with irregular macrocalcifications exhibited the twinkling artifact. It is important to recognize this artifact because it may lead to misdiagnosis of vascular flow in echocardiography.