Imaging electromagnetic boundary of microdevice using a wide field quantum microscope.

Imaging of electronic device surface or sub-surface electromagnetic fields under operating conditions is important for device design and diagnosis. In this study, we proposed a method to characterize specific magnetic field properties of electromagnetic devices at micron-scale using a solid-state quantum sensor, namely diamond nitrogen-vacancy (NV) centers. By employing a wide-field magnetic field measurement technique based on NV centers, we rapidly obtain the first-order magnetic field distribution of anomalous regions. Furthermore, we approximate the second-order magnetic field (magnetic gradient tensor) using the differential gradient method. To visualize the electromagnetic anomalous regions boundary, we utilize the tensor invariants of the magnetic gradient tensor components, along with their nonlinear combinations. The identification error rate of the anomalous regions is within 12.5%. Additionally, the electromagnetic field of anomalous regions is simulated showing the measurement accuracy. Our study shows that the experimental results are very similar to the theoretical simulation of the electromagnetic field (error: 7%). This work is essential for advancing electromagnetic field characterization of electronic devices and the advancement of quantum magnetic sensor applications.

Inhibitory effect of Shikonin on Candida albicans growth.

Our study showed that Shikonin (SK) could provide an action against almost all Candida albicans isolates tested. More importantly, to some Fluconazole (FCZ)-resistant Candida albicans, the action of SK (MIC(80) value 4 µg/mL) was shown to be >16 times higher than that of FCZ (MIC(80) >64 µg/mL). To clarify the mechanism underlying this action, we performed a comparative study in untreated control C. albicans and C. albicans treated with SK. In this study, we found that SK treatment increased generation of endogenous reactive oxygen species (ROS) and decreased mitochondrial membrane potential. Furthermore, anti-oxidants N-acetylcysteine (NAC) and glutathione (GSH) could reduce the antifungal activity of SK significantly in C. albicans. Our analyses also identified 9 differentially expressed genes, which were related to glycolysis-related genes (CDC19 and HXK2), fermentation-related genes (ALD5 and ADH1), antioxidant defense-related genes (SOD2 and SOD5), thioredoxin reductase-related gene (TRR1), mitochondrial respiratory electron transport chain-related gene (MRF1) and reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidoreductase-related gene (EBP1). These results suggest that mitochondrial aerobic respiration shift and endogenous ROS augmentation contribute to the action of SK against C. albicans.

Combination of baicalein and Amphotericin B accelerates Candida albicans apoptosis.

Candida albicans is the most important human fungal pathogen. Amphotericin (AmB) is a gold standard of antifungal treatment for fungi, but the severe side effect of this drug restricts its clinical application. In this study, the interaction of AmB and baicalein (BE) was investigated against thirty clinical isolates of C. albicans. Synergistic activities were determined using the checkerboard microdilution assay based on the fractional inhibitory concentration indices. Combination of BE and AmB accelerated C. albicans apoptosis accompanied with an increase of reactive oxygen species (ROS). Moreover, AmB increased the caspase activity and expression of the corresponding gene CaMCA1 in C. albicans. These effects were enhanced in the presence of BE. Deletion of CaMCA1 clearly attenuated AmB-induced apoptosis, indicating the involvement of CaMCA1-mediated caspase pathway in AmB-induced apoptosis and the synergistic action.