Identification of the functional domains of canine tetherin in antiviral activity against canine influenza virus

Canine influenza virus (CIV) is a respiratory pathogen that causes fever, coughing, and sneezing in dogs and is continuously circulating in canine populations. Tetherin is an antiviral host restriction factor mediated by interferon, capable of inhibiting the release of enveloped viruses from infected cells. The antiviral mechanism of tetherin is mainly due to its unusual topology, which includes a short N-terminal cytoplasmic tail (CT), a transmembrane (TM) domain, a coiled-coil extra-cellular region (CC), and a C-terminal glycosyl-phosphatidylinositol anchor (GPI). Previous studies have found that canine tetherin has the ability to limit the release of CIV, but its main antiviral domain remains unclear. In the present study, the potential CT, TM, CC, and GPI domains of canine tetherin were predicted through systemic bioinformatic analysis, and mutational variants of canine tetherin based on the four domains were constructed. Confocal microscopy demonstrated that the CT, TM, and CC domains are critical for the cell membrane localization of canine tetherin. The results of in vitro CIV infection experiments showed that the TM region is a critical functional domain of canine tetherin in limiting the replication of CIV. Our study will help better understand the antiviral activity of canine tetherin and the role of the structural domains of canine tetherin in inhibiting the replication of CIV

Differential Measurement for Cavity Ring-Down Spectroscopy with Dynamic Allan Variance

The method of dynamic Allan variance (DAVAR) is used to analyze the time-varying characteristics of a nonstationary signal and is thus incorporated to evaluate the random error in the cavity ring-down spectroscopy (CRDS) experiments. With the numerical simulation of the influence of instabilities of sudden, slow, or periodic changes on the measurement accuracy in the ring-down process, DAVAR is proved to be an effective way to evaluate random error characteristics in an interfering environment. In order to minimize influences of time-varying noises in CRDS, a practical differential measurement method is proposed, in which wavelength modulation is applied to detect the ring-down times at the absorption peak and the nonabsorption peak in a time-division manner. The validity of the differential measurement is proved with its ability to compensate the influence of the environment changes and improves the accuracy from 0.181 ppm to 0.00914 ppm. The differential measurement method can be used to correct the time-varying error in real time and is helpful to improve the environmental adaptability of the CRDS instrument.</jats:p

Differential Measurement for Cavity Ring-Down Spectroscopy with Dynamic Allan Variance

The method of dynamic Allan variance (DAVAR) is used to analyze the time-varying characteristics of a nonstationary signal and is thus incorporated to evaluate the random error in the cavity ring-down spectroscopy (CRDS) experiments. With the numerical simulation of the influence of instabilities of sudden, slow, or periodic changes on the measurement accuracy in the ring-down process, DAVAR is proved to be an effective way to evaluate random error characteristics in an interfering environment. In order to minimize influences of time-varying noises in CRDS, a practical differential measurement method is proposed, in which wavelength modulation is applied to detect the ring-down times at the absorption peak and the nonabsorption peak in a time-division manner. The validity of the differential measurement is proved with its ability to compensate the influence of the environment changes and improves the accuracy from 0.181 ppm to 0.00914 ppm. The differential measurement method can be used to correct the time-varying error in real time and is helpful to improve the environmental adaptability of the CRDS instrument

Partially coherent beam smoothing using a microlens array

The main issue in applying a microlens array as a beam homogenizer is the high intensity contrast resulting from the periodic structure. We present a practical solution to eliminate speckle patterns by using a diffuser that can convert a coherent source into a Gaussian Schell source with an adjustable coherence length. Based on numerical simulation and experimental results, the microlens should have the Fresnel number above 15, a large pitch when the target plane is fixed, and an appropriate D/σf ratio to obtain a spot with high uniformity. Moreover, a slight defocus of the observation surface within the range of ±1mm has a negligible effect on the uniformity of shaped spots the homogenized spot. Finally, the applications of the findings are presented.</jats:p