Electrostatic discharge induced degradation of optical-electrical properties and defect evolution of GaAs-based oxide-confined VCSELs.

GaAs-based oxide-confined vertical-cavity surface-emitting lasers (VCSELs) exhibit relatively low resistance against reliability-related damage. In order to gain a deeper understanding of the degradation and failure mechanism in oxide-confined VCSELs caused by electrostatic discharge (ESD)-induced defect proliferation, we investigated the effects of ESD stress on the degradation of optical-electrical characteristics and the evolution of defects in VCSELs under human body model test condition. The degradation threshold values for forward and reverse ESD pulse amplitudes were estimated to be 200 V and -50 V, respectively. Notably, VCSELs demonstrated greater sensitivity to reverse bias ESD compared to forward bias ESD. Analysis of optical emission and microstructure provided evidence that the device failure is attributed to an increase in ESD current density, leading to the multiplication of dark line defects (DLDs) originating from the edge of the device's oxide aperture. The formation of defects occurred suddenly in discrete events within small regions, rather than progressing gradually and uniformly. These defects propagated and led to damage across the entire active region. We believe that our results would be meaningful for improving the reliability of VCSEL in the future.

The Surface Modification and Antimicrobial Activity of Basic Magnesium Hypochlorite Nanoparticles.

The basic magnesium hypochlorite (BMH) nanoparticles were prepared by two micro-emulsion techniques and modified with sodium stearate. The influences of the main technical parameters such as the addition amount of sodium stearate, reaction temperature and reaction time on the Lipophilic degree (LD) of the modified BMH nanoparticles were investigated. The characteristics of the BMH nanoparticles were analysed by means of Malvern Instruments, transmission electron microscopy (TEM), water contact angle measurements, Fourier transform infrared spectroscopy (FTIR) and thermogravimetry analysis (TGA). The antimicrobial activity of the modified BMH nanoparticles was investigated with the antibacterial circle test. The results showed that the average size of the BMH nanoparticles was 305 nm. The BMH nanoparticles had been successfully modified by sodium stearate and the LD of.the modified BMH nanoparticles was 8.4% when the addition amount of sodium stearate was 0.15 g, the reaction temperature was 10 °C and the reaction time was 5 h. The dispersibility and hydrophobicity of the modified BMH nanoparticles were improved and the contact angle was up to 103 °, the modified BMH nanoparticles still had excellent antimicrobial activity after modification.

Integrating Study on Qualitative and Quantitative Characterization of the Major Constituents in Shuanghuanglian Injection with UHPLC/Q-Orbitrap-MS and UPLC-PDA.

As a clinically effective traditional Chinese medicine injection (TCMI), Shuanghuanglian injection (SHLI) is widely used in the treatment of upper respiratory tract infection and pneumonia. However, the shortage of quality analysis is a limitation that remains to be improved in the clinical application of SHLI. In this study, taking advantage of ultra-high-performance liquid chromatography tandem Q-Exactive Orbitrap high-resolution mass spectrometry (UHPLC/Q-Orbitrap-MS), 31 chemical components (eight organic acids, eleven flavonoids, five iridoid glycosides, four phenylethanoid glycosides, and three lignans) in SHLI were characterized, among which 22 components were unambiguously identified by reference compounds. The brief prediction results of network pharmacology indicated that the 22 targeted components may have anti-inflammatory, antibacterial, antiviral, and immunomodulatory activities. Using multiwavelength switching method, the 22 targeted components were quantified by ultra-performance liquid chromatography with photodiode array detector (UPLC-PDA) after the methodological validation. Based on the successfully established method, the total content of 22 components in 20 batches of SHLIs was efficiently determined with a slight variation between 10.25 and 11.28 mg/mL, which accounted for 38.7% in total solid of SHLI. This study performed a reliable chemical identification and provided a rapid and effective method for quality analysis, which contributed to the in-depth investigation and application of SHLI.

Identification of cryptotanshinone from Tongmai to inhibit thrombosis in zebrafish via regulating oxidative stress and coagulation cascade.

BACKGROUND: Thromboembolic events are leading causes of mortality and morbidity all over the world. Tongmai (TM) is a botanical drug with valid clinical efficacy and safety in the management of thrombosis and ischemic cardiovascular diseases, however, its active compounds and underlying mechanism are largely unclear. PURPOSE: To investigate the endogenous effects, therapeutic mechanism and active compounds of TM in thrombus formation. STUDY DESIGN: Combined with transgenic zebrafish models and high-content imaging system, this study evaluated the endogenous antithrombotic effects of TM and screened for the active compounds. METHODS: The PHZ-induced thrombotic model in erythrocytes or platelets labeled transgenic zebrafish were established, to dynamically evaluate the antithrombotic effects of TM. The oxidative damage levels were analyzed by specific fluorescent probes, and the expression levels of key factors in coagulation cascades and platelet activation were examined by QPCR. TM were dissected into fractions by reverse phase chromatography and subsequently screened for their antithrombotic effects in the transgenic fish models. The compounds of the active TM fraction were then analyzed by UPLC-Q-TOF analysis and further verified for their antithrombotic effects and mechanisms. RESULTS: In PHZ-induced zebrafish thrombotic model, TM incubation markedly increased cardiac blood flow, decreased peripheral erythrocytes aggregation, and recovered peripheral platelet circulation. Besides, the levels of oxidative stress and lipid peroxidation were increased in the PHZ-induced thrombotic fish, which were greatly decreased by TM treatment. Moreover, TM significantly reduced the expression of coagulation factor II (thrombin) and the downstream fibrinogen. In order to identify the active compounds of TM, four fractions were separated from the extract by reverse phase chromatography, which were subsequently screened for their antithrombotic effects in the fish model. As a result, fraction 4 showed the strongest effect in inhibiting thrombosis. Finally, through UPLC-Q-TOF analysis and endogenous screening, cryptotanshione was identified as the main active compound with antithrombotic effects. CONCLUSION: Our study demonstrated the endogenous antithrombotic effects of TM, which is possibly mediated by inhibiting oxidative stress and coagulation cascade. Cryptotanshione was identified as a major compound with antithrombotic activity and is a promising candidate for novel antithrombotic therapy.

Preparation and characterization of self-cleaning stable superhydrophobic linear low-density polyethylene.

Porous superhydrophobic linear low-density polyethylene (LLDPE) surface was prepared by a simple method. Its water contact angle and sliding angle were 153±2° and 10°, respectively. After contamination, 99% of the contaminant particles were removed from the superhydrophobic LLDPE surface using artificial rain. The superhydrophobic LLDPE surface showed high stability in the pH range from 2 to 13. When LLDPE samples were stored in ambient environment for one month, their water contact angle and sliding angle remained constant. Their superhydrophobic property was also maintained after annealing in the temperature range 10-90 °C.