Measurement of perfluoroalkyl substances in drinking water sources by DGT sampler with a novel fluorinated graphite binding gel.

Extensive use of per- and polyfluoroalkyl substances (PFASs) has resulted in their widespread presence in natural waters. Concern for public health requires reliable measurement methods for determining their distribution and risks. Here, a sampling method based on diffusive gradients in thin films (DGT) was developed for measuring PFASs in drinking water sources. Fluorinated graphite (FG) particles were used to prepare the DGT binding gel for selective enrichment of trace PFASs in an aqueous environment. The FG-DGT method did not show sensitivity to relevant environmental parameters including pH (5.0-9.0), ionic strength (0.001-0.5 M), or DOM concentration (0-30 mg/L). The FG-DGT had enough capacity for deployment of up to four months. Six traditional and emerging PFASs including PFOS, PFOA, PFHpA, PFHxS, PFNA, and 6:2 FTSA at the ng/L level were detected in two major reservoirs serving as public drinking water sources by FG-DGT method coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS). PFOA appeared at the highest observed concentrations in the drinking water sources. The research demonstrates that FG-DGT is an effective and efficient tool for monitoring PFASs in drinking water.

Synthesis and Third-Order Nonlinear Synergistic Effect of ZrO2/RGO Composites.

Tuning the third-order nonlinear properties of graphene by hybrid method is of great significance in nonlinear optics research. ZrO2/reduced graphene oxide (RGO) composites with different ZrO2 concentrations were prepared by a simple hydrothermal method. The morphology and structure show that ZrO2 nanoparticles were uniformly dispersed on the surface of graphene nanosheets. The nonlinear optical (NLO) characteristics of composites with different ZrO2 concentrations were studied by the Z-scan technique of 532 nm picosecond pulsed laser. The results showed that ZrO2/RGO composites had saturated absorption and positive nonlinear refraction characteristics. Meanwhile, the third-order nonlinear susceptibility of the ZrO2/RGO composite with a 4:1 mass ratio of ZrO2 to graphene oxide could reach 23.23 × 10-12 esu, which increased tenfold compared to RGO, and the nonlinear modulation depth reached 11.22%. Therefore, the NLO characteristics could be effectively adjusted by controlling the concentration of ZrO2, which lays a foundation for further research on the application of ZrO2/RGO composites in NLO devices.

Bibliotherapy for low sexual desire: evidence for effectiveness.

This study examines the effectiveness of bibliotherapy for low sexual desire among women, which is the most frequent sexual concern brought to counselors. Forty-five women responded to an advertisement for participation in a study on low sexual desire and were assigned to either the intervention or the wait-list control group. The intervention group completed the Hurlbert Index of Sexual Desire (HISD; Apt & Hurlbert, 1992) and the Female Sexual Function Index (FSFI; R. Rosen et al., 2000), read the self-help book under study in 6 weeks, and completed the measures a second time. The control group completed the same measures 6 weeks apart. Results demonstrated that the intervention group made statistically greater gains over time as compared with the control group on measures of sexual desire (HISD and FSFI Desire subscale), sexual arousal (FSFI Arousal subscale), sexual satisfaction (FSFI Satisfaction subscale), and overall sexual functioning (FSFI Total Score). A subset of participants in the intervention group participated in a 7-week follow-up study, and these participants maintained their gains in sexual desire and overall sexual functioning. Findings have important implications for future research on the efficacy of bibliotherapy generally and for low sexual desire specifically. Results also have vital implications for the treatment of low sexual desire.