A laser-induced breakdown spectroscopy technique for analyzing biological matter for the detection of biological hazards is investigated. Eight species were considered in our experiment: six bacteria and two pollens in pellet form. The experimental setup is described, then a cumulative intensity ratio is proposed as a quantitative criterion because of its linearity and reproducibility. Time-resolved laser-induced breakdown spectroscopy (TRELIBS) exhibits a good ability to differentiate among all these species, whatever the culture medium, the species or the strain. Thus we expect that TRELIBS will be a good candidate for a sensor of hazards either on surfaces or in ambient air.
The scanning vibrating electrode technique ͑SVET͒ and pH microscopy were used to study the effect of electrolyte composition and steel thickness on the precipitation of zinc-based corrosion products on the cut edge of galvanized steel. Current distributions were measured with the SVET, and the distribution of pH was measured using liquid membrane glass capillary electrodes. In NaCl solution, a clear correlation was observed between the spatial pattern of precipitated corrosion products, and the anodic/cathodic current and pH distribution:zinc dissolution occurred at localized points on the cut edge, suggesting that the zinc surface was passivated in this solution and that a pitting mechanism was predominate. Precipitated corrosion products formed rings around the anodic sites. In the presence of ͑NH 4 ͒ 2 SO 4 , the zinc surface was entirely active with only minimal corrosion product precipitation visible on the steel during the early stages of the reaction, and no significant increase in pH was observed in the vicinity of the cathodic reactions. At later stages, a film was formed and identified as a zinc hydroxysulfate compound by Raman spectroscopy. The experimental results are interpreted in terms of the equilibrium chemistry of the electrolytes.
Pleasure-seeking plays a role in prevention (means choices and use), and in the sexual quality of life of men who have sex with men (MSM). Since HIV is a major threat to MSM health, new means of prevention, like pre-exposure prophylaxis (PrEP), must meet the needs of MSM to be fully efficient. Using a psychosocial approach, we examined how pleasure-seeking plays a role in participation of MSM in “ANRS-IPERGAY,” a community-based trial on sexual health which included sexual on-demand PrEP. Thirteen semistructured collective interviews were conducted with 45 participants. First, we analyzed participants’ search for new prevention means due to previous failures in condom use. We found that participants perceived condoms as a barrier—both materially and symbolically—to pleasure and desire, causing anxiety and stress considering sexual intercourse. Second, we explored representations and attitudes concerning pleasure within the context of PrEP. We found that PrEP allowed participants to freely choose their desired sexual positions and to better enjoy intimacy. Third, we studied the sexual quality of life for PrEP users in ANRS-IPERGAY and found an improvement. Thanks to the community-based design of the trial, this new prevention tool became a means to develop agency and empowerment for participants, not only in negotiating individual prevention but also in opposing the normative and stigmatizing discourse on sexuality and HIV. In conclusion, pleasure-seeking appears to be an essential element of sexual fulfillment that needs to be integrated as a positive notion in the study of HIV prevention.
Background
Mycoplasma genitalium (MG) is an emerging pathogen among men who have sex with men (MSM) with raising rates of antibiotic resistance. In this study, we assessed the prevalence and incidence of MG infection in MSM enrolled in the open-label phase of the ANRS IPERGAY trial with on demand TDF/FTC for HIV prevention and the impact of doxycycline post-exposure prophylaxis (PEP).
Methods
210 subjects were tested at baseline and at 6 months by real-time PCR assays for MG detection in urine samples, oro-pharyngeal and anal swabs. Resistance to azithromycin (AZM), to fluoroquinolones (FQ) and to doxycycline were investigated in the French National Reference Centre of bacterial STI.
Results
The all-site prevalence of MG at baseline was 10.5% [6.3% in urine samples, 4.3% in anal swabs and 0.5% in throat swabs] and remained unchanged at 6 months whether or not PEP was used: 9.9% overall, 10.2% with PEP and 9.6% without. The overall rate of MG resistance (prevalent and incident cases) to AZM and FQ was 67.6% and 9.1%, respectively, with no difference between arms. An in vivo mutation of the MG 16S rRNA which could be associated with tetracycline resistance was observed in 12.5% of specimens tested.
Conclusions
The prevalence of MG infection among MSM on PrEP was high and its incidence was not decreased by doxycycline prophylaxis with a similar high rate of AZM- and FQ-resistance, raising challenging issues for the treatment of this STI and supporting current recommendations to avoid testing or treatment of asymptomatic MG infection.
A single high dose of oral tenofovir disoproxil fumarate/emtricitabine provides rapid and high blood levels of tenofovir and emtricitabine, with rapid diffusion of emtricitabine in saliva and rectal tissue.
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