Efficient postprocessing technique for fabricating surface nanoscale axial photonics microresonators with subangstrom precision by femtosecond laser

We demonstrated the subangstrom precise correction of surface nanoscale axial photonics (SNAP) micro-resonators by the femtosecond (fs) laser postprocessing technique for the first time. The internal stress can be induced by fs laser inscriptions in the fiber, causing nanoscale effective radius variation (ERV). However, the obtained ultraprecise fabrication usually undergoes multiple tries. Here, we propose a novel postprocessing technique based on the fs laser that significantly reduces the ERV errors and improves the fabrication precision without iterative corrections. The postexposure process is achieved at the original exposure locations using lower pulse energy than that in the initial fabrication process. The results show that the ERV is nearly proportional to the pulse energy of the postexposure process. The slope of the ERV versus the pulse energy is 0.07 Å/nJ. The maximum of the postprocessed ERV can reach 8.0 Å. The repeatability was experimentally verified by accomplishing the correction on three SNAP microresonators with the precision of 0.75 Å. The developed fabrication technique with fs laser enables SNAP microresonators with new breakthrough applications for optomechanics and filters

Digital crowdsourced intervention to promote HIV testing among MSM in China: study protocol for a cluster randomized controlled trial.

BACKGROUND: Men who have sex with men (MSM) are an important HIV key population in China. However, HIV testing rates among MSM remain suboptimal. Digital crowdsourced media interventions may be a useful tool to reach this marginalized population. We define digital crowdsourced media as using social media, mobile phone applications, Internet, or other digital approaches to disseminate messages developed from crowdsourcing contests. The proposed cluster randomized controlled trial (RCT) study aims to assess the effectiveness of a digital crowdsourced intervention to increase HIV testing uptake and decrease risky sexual behaviors among Chinese MSM. METHODS: A two-arm, cluster-randomized controlled trial will be implemented in eleven cities (ten clusters) in Shandong Province, China. Targeted study participants will be 250 MSM per arm and 50 participants per cluster. MSM who are 18 years old or above, live in the study city, have not been tested for HIV in the past 3 months, are not living with HIV or have never been tested for HIV, and are willing to provide informed consent will be enrolled. Participants will be recruited through banner advertisements on Blued, the largest gay dating app in China, and in-person at community-based organizations (CBOs). The intervention includes a series of crowdsourced intervention materials (24 images and four short videos about HIV testing and safe sexual behaviors) and HIV self-test services provided by the study team. The intervention was developed through a series of participatory crowdsourcing contests before this study. The self-test kits will be sent to the participants in the intervention group at the 2nd and 3rd follow-ups. Participants will be followed up quarterly during the 12-month period. The primary outcome will be self-reported HIV testing uptake at 12 months. Secondary outcomes will include changes in condomless sex, self-test efficacy, social network engagement, HIV testing social norms, and testing stigma. DISCUSSION: Innovative approaches to HIV testing among marginalized population are urgently needed. Through this cluster randomized controlled trial, we will evaluate the effectiveness of a digital crowdsourced intervention, improving HIV testing uptake among MSM and providing a resource in related public health fields. TRIAL REGISTRATION: ChiCTR1900024350 . Registered on 6 July 2019

Amino-Modified Tetraphenylethene Derivatives as Nucleic Acid Stain: Relationship between the Structure and Sensitivity

A series of new amino-functionalized tetraphenylethene (TPE) derivatives were designed and synthesized to study the effect of molecular structures on the detection of nucleic acid. Contrastive studies revealed that the number of binding groups, the length of hydrophobic linking arm and the configuration of TPE molecule all play important roles on the sensitivity of the probes in nucleic acid detection. <i>Z</i>-TPE3 with two binding amino groups, long linking arms, and cis configuration was found to be the most sensitive dye in both solution and gel matrix. <i>Z</i>-TPE3 is able to stain dsDNA with the lowest amount of 1 ng and exclusively stain 40 ng of short oligonucleotide with only 10 nt. This work is of important significance for the further design of TPE probes as biosensors with higher sensitivity