Environmental contamination by ⁹⁹Tc(VII) from radioactive wastewater streams is of particular concern due to the long half-life of ⁹⁹Tc and high mobility of pertechnetate. Herein, we report a novel MXene-polyelectrolyte nanocomposite with three-dimensional networks for enhanced removal of perrhenate, which is pertechnetate simulant. The introduction of poly(diallyldimethylammonium chloride) (PDDA) regulates the surface charge and improves the stability of Ti₂CT _x nanosheet, resulting in Re(VII) removal capacity of up to 363 mg g^-1, and fast sorption kinetics. The Ti₂CT _x/PDDA nanocomposite furthermore exhibits good selectivity for ReO₄^- when competing anions (such as Cl^- and SO₄^2-) coexist at a concentration of 1800 times. The immobilization mechanism was confirmed as a sorption-reduction process by batch sorption experiments and X-ray photoelectron spectroscopy. The pH-dependent reducing activity of Ti₂CT _x/PDDA nanocomposite toward Re(VII) was clarified by X-ray absorption spectroscopy. As the pH increases, the local environment gradually changes from octahedral-coordinated Re(IV) to tetrahedral-coordinated Re(VII). The overall results suggest that Ti₂CT _x/PDDA nanocomposite may be a promising candidate for efficient elimination of Tc contamination. The reported surface modification strategy might result in applications of MXene-based materials in environmental remediation of other oxidized anion pollutants.

Homoprejudiced violence is a type of aggression against an individual or a community based on their actual or perceived sexual orientation. It may be linked to risks of acquiring HIV/STI via psychosocial variables. This study explored the association between homoprejudiced violence experiences and high-risk sexual behaviors, and potential psychosocial mediators. Using cross-sectional survey data collected in China through Blued among men who have sex with men (MSM) in January 2021, this study conducted multiple mediation analyses. Standard instruments were used to collect data on depressive symptoms in the last two weeks (PHQ-9), recreational drug usage in the last three months, and ever experiencing homoprejudiced violence (12-item survey instrument). Dependent variables were having condomless anal sex and having three or more sexual partners in the last three months. Among 1828 MSM, nearly half (847, 46%) had experienced homoprejudiced violence. Twenty-three percent (427) reached a score that suggested moderate or severe depression and 35% (644) had used recreational drugs. In the last three months, 40% (731) had condomless anal sex and 34% (626) had three or more sexual partners. The indirect mediational coefficients through depression on condomless anal sex and multiple sexual partners were 0.04 (95% CI: [0.02, 0.07]) and 0.02 (95% CI: [0.001, 0.05]), respectively. The indirect mediational coefficient of homoprejudiced violence experience on multiple sexual partners through recreational drug use was 0.05 (95% CI: [0.03, 0.08]). These findings suggest that more comprehensive interventions are needed to address the syndemic of homoprejudiced violence, mental health issues, and HIV/STI-related risks.