Mean Differential Continuous Pulse Method for Accurate Optical Measurements of Light-Emitting Diodes and Laser Diodes

Limited sources exist for the application of germicidal ultraviolet (GUV) radiation. Ultraviolet light-emitting diodes (UV-LEDs) have significantly improved in efficiency and are becoming another viable source for GUV. We have developed a mean differential continuous pulse method (M-DCP method) for optical measurements of light-emitting diodes (LEDs) and laser diodes (LDs). The new M-DCP method provides an improvement on measurement uncertainty by one order of magnitude compared to the unpublished differential continuous pulse method (DCP method). The DCP method was already a significant improvement of the continuous pulse method (CP method) commonly used in the LED industry. The new M-DCP method also makes it possible to measure UV-LEDs with high accuracy. Here, we present the DCP method, discuss the potential systematic error sources in it, and present the M-DCP method along with its reduced systematic errors. This paper also presents the results of validation measurement of LEDs using the M-DCP method and common test instruments.

The Alarm Burden of Excess Continuous Pulse Oximetry Monitoring Among Patients With Bronchiolitis

Guidelines discourage continuous pulse oximetry monitoring of hospitalized infants with bronchiolitis who are not receiving supplemental oxygen. Excess monitoring is theorized to contribute to increased alarm burden, but this burden has not been quantified. We evaluated admissions of 201 children (aged 0-24 months) with bronchiolitis. We categorized time ≥60 minutes following discontinuation of supplemental oxygen as “continuously monitored (guideline-discordant),” “intermittently measured (guideline-concordant),” or “unable to classify.” Across 4402 classifiable hours, 77% (11,101) of alarms occurred during periods of guideline-discordant monitoring. Patients experienced a median of 35 alarms (interquartile range [IQR], 10-81) during guideline-discordant, continuously monitored time, representing a rate of 6.7 alarms per hour (IQR, 2.1-12.3). In comparison, the median hourly alarm rate during periods of guideline-concordant intermittent measurement was 0.5 alarms per hour (IQR, 0.1-0.8). Reducing guideline-discordant monitoring in bronchiolitis patients would reduce nurse alarm burden.

Medium optimization and subsequent fermentative regulation for the scaled-up production of anti-tuberculosis drug leads ilamycin-E1/E2

Tuberculosis (TB) and its emerged drug resistance exert huge threats on the global health, therefore development of novel anti-TB antibiotics is very essential. Ilamycin-E1/E2 is a pair of cycloheptapeptide enantiomers obtained from a marine-derived Streptomyces atratus SCSIO ZH16-ΔilaR mutant, and become promising anti-TB lead compounds due to their significant anti-TB activities, but their low titer hampered the further clinical development. In this work, the statistical Plackett-Burman design (PBD) model was applied to screen out bacterial peptone as the only significant but negative factor affecting the ilamycin-E1/E2 production. Subsequent single factor optimization revealed that replacement of bacterial peptone with malt extract eliminated the accumulation of porphyrin-type competitive byproduct, and the titer of ilamycin-E1/E2 in shaking flasks was improved from original 13.6±0.8 to 142.7±5.7 mg/L for about 10.5 folds. Furthermore, a pH coordinated feeding strategy was first adopted in scaled-up production of ilamycin-E1/E2. The obtained titer of ilamycin-E1/E2 in 30L was 169.8±2.5 mg/L, while in 300L fermentor was only 131.5±7.5 mg/L due to the unsynchronization of feeding response and pH change. Therefore, the continuous pulse feeding strategy was further applied in 300L fermentor and finally achieved 415.7±29.2 mg/L ilamycin-E1/E2, which represented about 30.5 folds improvement at last. Our work provided the solid basis to achieve sufficient ilamycin-E1/E2 lead compounds and support their potential anti-TB drug development.

Thermal Simulation of the Continuous Pulse Discharge for Electro-spark Deposition Diamond Wire Saw

Due to their excellent physical and mechanical properties, third-generation super-hard semiconductor materials (such as SiC, GaN) are widely used in the field of microelectronics. However, due to its ultra-high hardness, the machining is very difficult, which has become the bottleneck of its development. The electro-spark deposition (ESD) process can deposit electrode materials on the substrate under the condition of low heat input to achieve metallurgical bonding between metal materials. And it can improve the wear resistance, corrosion resistance, and repair the size of the workpiece. It has been widely used in the field of surface modification engineering. It can effectively improve the bonding strength of the abrasive grains, and the sawing ability of the wire saw to make the consolidated diamond wire saw by the ESD process. Due to its thin matrix and poor thermal properties, the saw wire is easy to burning or even breaking in the manufacturing process. At present, the selection of pulse interval time in the ESD process is generally determined by the duty factor. However, the pulse interval time selected according to duty factor is difficult to meet the heat dissipation requirements of electro-spark deposition diamond wire saw (ESDDWS). In this paper, two kinds of motion modes of ESDDWS manufacturing are put forward, according to the manufacturing characteristics of ESDDWS. The boundary conditions of the continuous pulse discharge of ESDDWS are established. The thermal simulations of continuous pulse discharge of ESDDWS under two motion modes are analyzed. According to the simulation results, the basis of the value of pulse interval in the ESDDWS process is put forward. The effect of pulse interval time on the mechanical performance of the wire saw is analyzed experimentally. The results show that the discharge interval time selected base on the simulation results can ensure the continuous production of the ESDDWS.