Reliable Determination of Contact Angle from the Liquid Fence.

Traditional methods of measuring contact angles often face difficulties in precisely defining the three-phase contact points. A novel method for accurately defining three-phase contact points based on liquid fences is proposed in this article. The tested liquid is placed in a cubic liquid fence composed of a pair of narrow strips of the tested solid and a pair of transparent wide strips. The transparent wide strip serves as the measurement window, and the surface tension of the liquid on it can be almost ignored. In experimental measurements, the horizontal coordinates of the end points of the liquid profile are fixed by the liquid fence, thus determining the horizontal coordinates of the three-phase contact points, which helps to accurately survey the contact angle. Additionally, since the parameters of the liquid fence are known, the size of the contact angle can also be calculated by measuring the height of the liquid level dome inside the liquid fence. Using the electric wetting effect as an example, we experimentally extracted a series of liquid contour maps with circular tops and square columns under varying voltages. The relationship curve between contact angle and voltage variation was obtained using the above methods, and a contact angle variation tendency seemed to agree well with the theoretical value.

Tunable fiber attenuator for electrically wet-driven micromirrors.

Herein we report an electronically controlled tunable fiber-optic attenuator that leverages the microfluidic electro-wetting effect, which enables a fine-tuning of the solid-liquid interface wetting angle to control the micro-reflector, thus regulating the lens fiber coupling efficiency. Theoretical calculations indicated an optical attenuation regulation effect of 0-45.0 dB in the voltage range of 0-30.0 V. Experimental results align closely with theoretical calculations, demonstrating an attenuation range of 0.59-43.0 dB within a voltage variation range of 0-25.0 V, with control accuracy of 0.56 dB. Our study unveils the potential for designing fiber-optic attenuators with varying tuning accuracy by precisely adjusting the solid-liquid interface wetting angle.

Celastrol Alleviates Mitochondrial Oxidative Stress and Brain Injury After Intracerebral Hemorrhage by Promoting OPA1-Dependent Mitochondrial Fusion.

Mitochondrial oxidative stress is one of the characteristics of secondary brain injury (SBI) after intracerebral hemorrhage (ICH), contributing largely to the apoptosis of neurons. Celastrol, a quinone methide triterpene that possesses antioxidant and mitochondrial protective properties, has emerged as a neuroprotective agent. However, the activity of celastrol has not been tested in ICH-induced SBI. In this study, we found that celastrol could effectively alleviate neurological function deficits and reduce brain oedema and neuronal apoptosis caused by ICH. Through electron microscopy, we found that celastrol could significantly attenuate mitochondrial morphology impairment. Therefore, we tested the regulatory proteins of mitochondrial dynamics and found that celastrol could reverse the downwards trend of OPA1 expression after ICH. In view of this, by culturing OPA1-deficient primary neurons and constructing neuron-specific OPA1 conditional knockout mice, we found that the protective effects of celastrol on mitochondrial morphology and function after ICH were counteracted in the absence of OPA1. Further experiments also showed that OPA1 is indispensable for the protective effects of celastrol on ICH-induced secondary brain injury. In summary, we have demonstrated that celastrol is a potential drug for the treatment of ICH and have revealed a novel mechanism by which celastrol exerts its antioxidant effects by promoting OPA1-mediated mitochondrial fusion.