Environmental Degradation of Microplastics: How to Measure Fragmentation Rates to Secondary Micro- and Nanoplastic Fragments and Dissociation into Dissolved Organics.

Understanding the environmental fate of microplastics is essential for their risk assessment. It is essential to differentiate size classes and degradation states. Still, insights into fragmentation and degradation mechanisms of primary and secondary microplastics into micro- and nanoplastic fragments and other degradation products are limited. Here, we present an adapted NanoRelease protocol for a UV-dose-dependent assessment and size-selective quantification of the release of micro- and nanoplastic fragments down to 10 nm and demonstrate its applicability for polyamide and thermoplastic polyurethanes. The tested cryo-milled polymers do not originate from actual consumer products but are handled in industry and are therefore representative of polydisperse microplastics occurring in the environment. The protocol is suitable for various types of microplastic polymers, and the measured rates can serve to parameterize mechanistic fragmentation models. We also found that primary microplastics matched the same ranking of weathering stability as their corresponding macroplastics and that dissolved organics constitute a major rate of microplastic mass loss. The results imply that previously formed micro- and nanoplastic fragments can further degrade into water-soluble organics with measurable rates that enable modeling approaches for all environmental compartments accessible to UV light.

Effect of Polymer Properties on the Biodegradation of Polyurethane Microplastics.

The release of fragments from plastic products, that is, secondary microplastics, is a major concern in the context of the global plastic pollution. Currently available (thermoplastic) polyurethanes [(T)PU] are not biodegradable and therefore should be recycled. However, the ester bond in (T)PUs might be sufficiently hydrolysable to enable at least partial biodegradation of polyurethane particles. Here, we investigated biodegradation in compost of different types of (T)PU to gain insights into their fragmentation and biodegradation mechanisms. The studied (T)PUs varied regarding the chemistry of their polymer backbone (aromatic/aliphatic), hard phase content, cross-linking degree, and presence of a hydrolysis-stabilizing additive. We developed and validated an efficient and non-destructive polymer particle extraction process for partially biodegraded (T)PUs based on ultrasonication and density separation. Our results showed that biodegradation rates and extents decreased with increasing cross-linking density and hard-segment content. We found that the presence of a hydrolysis stabilizer reduced (T)PU fragmentation while not affecting the conversion of (T)PU carbon into CO2. We propose a biodegradation mechanism for (T)PUs that includes both mother particle shrinkage by surface erosion and fragmentation. The presented results help to understand structure-degradation relationships of (T)PUs and support recycling strategies.

Maternal serum cytokines at 30-33 weeks in the prediction of preeclampsia.

OBJECTIVE: The aim of this case-control study at 30-33 weeks, a few days or weeks before the clinical onset of preeclampsia (PE), was to assess whether serum concentrations of cytokines differ between patients who are destined to develop PE and those with uncomplicated pregnancies. METHODS: A panel of cytokines was measured using Luminex technology at 30-33 weeks' gestation in 39 cases that developed PE at or after 34 weeks and 117 unaffected controls. RESULTS: The serum concentrations of most analysed cytokines were no different in women who developed PE than in controls. The proportions of women with detectable concentrations of MIP-1α and IL-8 were significantly lower in those with PE than in the controls (MIP-1α: 14/39 vs 76/117, P = 0.003; IL-8:13/39 vs 83/117, P < 0.0001). The median maternal serum concentration of IL-1ß was significantly lower in the PE cases than in the controls (0.38 pg/mL, range 0.01-0.92, vs 0.60 pg/mL, range 0.02-3.54, P = 0.005). CONCLUSION: Our findings do not lend support to the hypothesis that systemic inflammation precedes the onset of PE or that cytokines are good markers for such inflammation and certainly the panel of cytokines we examined does not provide useful prediction of subsequent development of PE.

Chromosome-selective sequencing of maternal plasma cell-free DNA for first-trimester detection of trisomy 21 and trisomy 18.

OBJECTIVE: The purpose of this study was to assess the prenatal detection rate of trisomy 21 and 18 and the false-positive rate by chromosome-selective sequencing of maternal plasma cell-free DNA. STUDY DESIGN: Nested case-control study of cell-free DNA was examined in plasma that was obtained at 11-13 weeks before chorionic villous sampling from 300 euploid pregnancies, 50 pregnancies with trisomy 21, and 50 pregnancies with trisomy 18. Laboratory personnel were blinded to fetal karyotype. RESULTS: Risk scores for trisomy 21 and 18 were given for 397 of the 400 samples that were analyzed. In all 50 cases of trisomy 21, the risk score for trisomy 21 was ≥ 99%, and the risk score for trisomy 18 was ≤ 0.01%. In all 50 cases of trisomy 18, the risk score for trisomy 21 was ≤ 0.01%, and the risk score for trisomy 18 was ≥ 99% in 47 cases, 98.8% in 1 case, 88.5% in 1 case, and 0.11% in 1 case. In 3 of the 300 euploid pregnancies (1%), no risk score was provided, because there was failed amplification and sequencing. In the remaining 297 cases, the risk score for trisomy 21 was ≤ 0.01%, and the risk score for trisomy 18 was ≤ 0.01% in 295 cases, 0.04% in 1 case, and 0.23% in 1 case. Therefore, the sensitivity for detecting trisomy 21 was 100% (50/50 cases); the sensitivity for trisomy 18 was 98% (49/50 cases), and the specificity was 100% (297/297 cases). CONCLUSION: In this study, chromosome-selective sequencing of cell-free DNA separated all cases of trisomy 21 and 98% of trisomy 18 from euploid pregnancies.

Maternal serum tumour necrosis factor receptor 1 (TNF-R1) at 30-33 weeks in the prediction of preeclampsia.

OBJECTIVE: To investigate the potential value of maternal serum concentration of tumour necrosis factor receptor 1 (TNF-R1) at 30-33 weeks' gestation in the prediction of preeclampsia (PE) developing at or after 34 weeks. METHODS: Serum TNF-R1 was measured at 11-13 and at 30-33 weeks' gestation in a case-control study of 50 cases that developed PE at or after 34 weeks and 250 unaffected controls. The measured values of TNF-R1 were converted into multiples of the normal median (MoM) and the MoM values in the PE and control groups were compared. RESULTS: The median MoM TNF-R1 was significantly increased at both 11-13 weeks (1.094 MoM versus 1.003 MoM) and at 30-33 weeks (1.101 MoM versus 1.006 MoM). In screening for PE by a combination of maternal characteristics and serum TNF-R1 at 30-33 weeks, the estimated detection rates of PE at false positive rates of 5% and 10% were 32.0% and 40.0%, respectively. CONCLUSION: Screening by maternal characteristics and serum TNF-R1 at 30-33 weeks could be effective in identifying some of the cases that will subsequently develop PE.

Natural killer cells and their activation status in normal pregnancy.

Increased peripheral blood-activated NK cell counts are associated with increased risk of miscarriage and failed in vitro fertilization treatment. However, assessment of activated peripheral NK cells in normal and pathological pregnancies beyond implantation and early miscarriage has not been described. Total CD69 expressing NK cells counts were measured by flow cytometry in healthy women with singleton pregnancies, including 45 at 11(+6)-13(+6) weeks' gestation, 46 at 20(+0)-22(+4) weeks, and 42 at 31(+6)-33(+5) weeks. The number of peripheral blood NK cells decreased, whereas the percentage of activated CD69 expressing NK cells increased from the first to the third trimester of pregnancy. This study shows the course of peripheral blood NK cells and activated CD69 expressing NK cells in uncomplicated nulliparous singleton pregnancies. This is a first step in understanding their implication in pathological pregnancies.

Among the missing: content on lesbian and gay people in social work journals.

Lesbian and gay issues are barely visible in the social work literature. This study examined the content of articles on homosexuality that were published in four major social work journals between 1988 and 1997. Articles were coded according to their focus on either HIV/AIDS and the gay community or other issues pertaining to lesbians and gay men. Articles were also coded as client focused, worker focused, or macro focused. Two-thirds of the 77 articles published on homosexuality focused on HIV/AIDS. Most articles reflected a problem-oriented view of gay and lesbian people; few addressed heterosexism or environmental interventions. More literature is needed that focuses on strengths, heterosexist conditions, and social justice for lesbian and gay people.