Study on the effect of a cold environment on the quality of three video laryngoscopes: McGrath MAC, GlideScope Ranger, and Pentax Airway Scope

Objective Several environmental factors influence the prehospital use of video laryngoscopes (VLs). For example, fogging of the VL lens can occur in cold environments, and the low temperature can cause the VLs to malfunction. As relevant research on the effect of environment on VLs is lacking, we aimed to study the effect of a cold environment on three commonly used VLs. Methods McGrath MAC, Pentax Airway Scope (AWS), and GlideScope Ranger were exposed to temperatures of -5°C, -10°C, -20°C, and -25°C for 1 hour each and then applied to a manikin in a thermohydrostat room 5 times. Immediately after turning on the power and inserting the blade, the time until an appropriate glottic image appeared on the screen was measured. Results McGrath MAC was able to accomplish immediate intubation regardless of the temperature drop. However, GlideScope Ranger required an average of 4.9 seconds (-5°C to -20°C) and 10.1 seconds (-25°C) until appropriate images were obtained for intubation. AWS showed adequate image acquisition immediately after blade insertion despite slight fogging at -20°C, but at -25°C, images suitable for intubation did not appear on the screen for an average of 4.7 minutes. Conclusion All three devices appear to be usable without any limitations up to -20°C. However, GlideScope Ranger and AWS may not produce images immediately at temperatures below -25°C. Thus, medical practitioners performing VL in a cold environment should be aware of the characteristics of the VL devices in advance

Universal field-tunable terahertz emission by ultrafast photoinduced demagnetization in Fe, Ni, and Co ferromagnetic films

We report a universal terahertz (THz) emission behavior from simple Ni, Fe, and Co metallic ferromagnetic films, triggered by the femtosecond laser pulse and subsequent photoinduced demagnetization on an ultrafast time scale. THz emission behavior in ferromagnetic films is found to be consistent with initial magnetization states controlled by external fields, where the hysteresis of the maximal THz emission signal is observed to be well-matched with the magnetic hysteresis curve. It is experimentally demonstrated that the ultrafast THz emission by the photoinduced demagnetization is controllable in a simple way by external fields as well as pump fluences. © 2020, The Author(s).1

Role of non-thermal electrons in ultrafast spin dynamics of ferromagnetic multilayer

Understanding of ultrafast spin dynamics is crucial for future spintronic applications. In particular, the role of non-thermal electrons needs further investigation in order to gain a fundamental understanding of photoinduced demagnetization and remagnetization on a femtosecond time scale. We experimentally demonstrate that non-thermal electrons existing in the very early phase of the photoinduced demagnetization process play a key role in governing the overall ultrafast spin dynamics behavior. We simultaneously measured the time-resolved reflectivity (TR-R) and the magneto-optical Kerr effect (TR-MOKE) for a Co/Pt multilayer film. By using an extended three-temperature model (E3TM), the quantitative analysis, including non-thermal electron energy transfer into the subsystem (thermal electron, lattice, and spin), reveals that energy flow from non-thermal electrons plays a decisive role in determining the type I and II photoinduced spin dynamics behavior. Our finding proposes a new mechanism for understanding ultrafast remagnetization dynamics. © 2020, The Author(s).1

An Antireflective Nanostructure Array Fabricated by Nanosilver Colloidal Lithography on a Silicon Substrate

An alternative method is presented for fabricating an antireflective nanostructure array using nanosilver colloidal lithography. Spin coating was used to produce the multilayered silver nanoparticles, which grew by self-assembly and were transformed into randomly distributed nanosilver islands through the thermodynamic action of dewetting and Oswald ripening. The average size and coverage rate of the islands increased with concentration in the range of 50–90 nm and 40–65%, respectively. The nanosilver islands were critically affected by concentration and spin speed. The effects of these two parameters were investigated, after etching and wet removal of nanosilver residues. The reflection nearly disappeared in the ultraviolet wavelength range and was 17% of the reflection of a bare silicon wafer in the visible range

Efficient SAR Azimuth Ambiguity Reduction in Coastal Waters Using a Simple Rotation Matrix: The Case Study of the Northern Coast of Jeju Island

Azimuth ambiguities, or ghosts on SAR images, represent one of the main obstacles for SAR applications involving coastal monitoring activities such as ship detection. While most previous methods based on azimuth antenna pattern and direct filtering are effective for azimuth ambiguity suppression, they may not be effective for fast cruising small ships. This paper proposes a unique approach for the reduction of azimuth ambiguities or ghosts in SAR single-look complex (SLC) images using a simple rotation matrix. It exploits the fact that the signal powers of azimuth ambiguities are concentrated on narrow bands, while those of vessels or other true ground targets are dispersed over broad bands. Through sub-aperture processing and simple axis rotation, it is possible to concentrate the dispersed energy of vessels onto a single axis while the ghost signal powers are dispersed onto three different axes. Then, the azimuth ambiguities can be easily suppressed by a simple calculation of weighted sum and difference, while preserving vessels. Applied results achieved by processing TerrSAR-X SLC images are provided and discussed. An optimum weight of 0.5 was determined by Receiver Operating Characteristic (ROC) analysis. Capabilities of ship detection from the test image were significantly improved by removing 93% of false alarms. Application results demonstrate its high performance of ghost suppression. This method can be employed as a pre-processing tool of SAR images for ship detection in coastal waters

Cardiac arrest associated with pneumorrhachis and pneumocephalus after epidural analgesia: two case reports

Abstract Background Epidural analgesia has become a common procedure to provide excellent pain relief with few complications. Pneumorrhachis and pneumocephalus are rare complications of unintentional dural puncture and injection of air into the subarachnoid or subdural space. No cases of cardiac arrest associated with these complications have been reported in the literature previously. Case presentation We report cases of pneumorrhachis and pneumocephalus in two Korean women who previously visited a local pain clinic and underwent epidural analgesia. Thereafter, they were admitted to the emergency department with cardiac arrest. Cardiopulmonary resuscitation was performed on these patients, and return of spontaneous circulation was achieved. The brain and spine computed tomographic scans showed pneumorrhachis and pneumocephalus, respectively. These cases demonstrate that pneumorrhachis and pneumocephalus may occur after epidural analgesia, which may be associated with cardiac arrest in patients. Conclusions If cardiac arrest occurs after epidural analgesia, pneumocephalus and pneumorrhachis should be considered as its cause. Although epidural analgesia is a common procedure, caution is warranted during this procedure