Correction: π-Facial selectivity in the Diels–Alder reaction of glucosamine-based chiral furans and maleimides

Correction for 'π-Facial selectivity in the Diels-Alder reaction of glucosamine-based chiral furans and maleimides' by Cornelis H. M. van der Loo et al., Org. Biomol. Chem., 2023, 21, 1888-1894, https://doi.org/10.1039/D2OB02221D. </p

Correction: π-Facial selectivity in the Diels–Alder reaction of glucosamine-based chiral furans and maleimides

Correction for 'π-Facial selectivity in the Diels-Alder reaction of glucosamine-based chiral furans and maleimides' by Cornelis H. M. van der Loo et al., Org. Biomol. Chem., 2023, 21, 1888-1894, https://doi.org/10.1039/D2OB02221D. </p

Correction: π-Facial selectivity in the Diels–Alder reaction of glucosamine-based chiral furans and maleimides

Correction for 'π-Facial selectivity in the Diels-Alder reaction of glucosamine-based chiral furans and maleimides' by Cornelis H. M. van der Loo et al., Org. Biomol. Chem., 2023, 21, 1888-1894, https://doi.org/10.1039/D2OB02221D. </p

Correction: π-Facial selectivity in the Diels–Alder reaction of glucosamine-based chiral furans and maleimides

Correction for 'π-Facial selectivity in the Diels-Alder reaction of glucosamine-based chiral furans and maleimides' by Cornelis H. M. van der Loo et al., Org. Biomol. Chem., 2023, 21, 1888-1894, https://doi.org/10.1039/D2OB02221D. </p

Shelf‐basin exchange times of Arctic surface waters estimated from \u3csup\u3e228\u3c/sup\u3eTH/\u3csup\u3e228\u3c/sup\u3eRa disequilibrium

The transpolar drift is strongly enriched in 228Ra accumulated on the wide Arctic shelves with subsequent rapid offshore transport. We present new data of Polarstern expeditions to the central Arctic and to the Kara and Laptev seas. Because 226Ra activities in Pacific waters are 30% higher than in Atlantic waters, we correct 226Ra for the Pacific admixture when normalizing 228Ra with 226Ra. The use of 228Ra decay as age marker critically depends on the constancy in space and time of the source activity, a condition that has not yet adequately been tested. While 228Ra decays during transit over the central basin, ingrowth of 228Th could provide an alternative age marker. The high 228Th/228Ra activity ratio (AR = 0.8–1.0) in the central basins is incompatible with a mixing model based on horizontal eddy diffusion. An advective model predicts that 228Th grows to an equilibrium AR, the value of which depends on the scavenging regime. The low AR over the Lomonosov Ridge (AR = 0.5) can be due to either rapid transport (minimum age without scavenging 1.1 year) or enhanced scavenging. Suspended particulate matter load (derived from beam transmission and particulate 234Th) and total 234Th depletion data show that scavenging, although extremely low in the central Arctic, is enhanced over the Lomonosov Ridge, making an age of 3 years more likely. The combined data of 228Ra decay and 228Th ingrowth confirm the existence of a recirculating gyre in the surface water of the eastern Eurasian Basin with a river water residence time of at least 3 year

Grain size effects on Th-230(xs) inventories in opal-rich and carbonate-rich marine sediments

Excess Thorium-230 (230Thxs) as a constant flux tracer is an essential tool for paleoceanographic studies, but its limitations for flux normalization are still a matter of debate. In regions of rapid sediment accumulation, it has been an open question if 230Thxs-normalized fluxes are biased by particle sorting effects during sediment redistribution. In order to study the sorting effect of sediment transport on 230Thxs, we analyzed the specific activity of 230Thxs in different particle size classes of carbonate-rich sediments from the South East Atlantic, and of opal-rich sediments from the Atlantic sector of the Southern Ocean. At both sites, we compare the 230Thxs distribution in neighboring high vs. low accumulation settings. Two grain-size fractionation methods are explored. We find that the 230Thxs distribution is strongly grain size dependent, and 5090% of the total 230Thxs inventory is concentrated in fine material smaller than 10 &#956;m, which is preferentially deposited at the highaccumulation sites. This leads to an overestimation of the focusing factor &#936;, and consequently to an underestimation of the vertical flux rate at such sites. The distribution of authigenic uranium indicates that fine organic-rich material has also been re-deposited from lateral sources. If the particle sorting effect isconsidered in the flux calculations, it reduces the estimated extent of sediment focusing. In order to assess the maximum effect of particle sorting on &#936;, we present an extreme scenario, in which we assume a lateralsediment supply of only fine material (b10 &#956;m). In this case, the focusing factor of the opal-rich core would be reduced from &#936;=5.9 to &#936;=3.2. In a more likely scenario, allowing silt-sized material to be transported, &#936; is reduced from 5.9 to 5.0 if particle sorting is taken into consideration. The bias introduced by particle sorting is most important for strongly focused sediments. Comparing 230Thxs-normalized mass fluxes biased by sorting effects with uncorrected mass fluxes, we suggest that 230Thxs-normalization is still a valid tool to correct for lateral sediment redistribution. However,differences in focusing factors between core locations have to be evaluated carefully, taking the grain size distributions into consideration

Understanding the effect of an educational intervention to optimize HIV testing strategies in primary care in Amsterdam - results of a mixed-methods study.

BACKGROUND: In the Netherlands, general practitioners (GPs) play a key role in provider-initiated HIV testing, but opportunities for timely diagnosis are regularly missed. We implemented an educational intervention to improve HIV testing by GPs from 2015 to 2020, and observed a 7% increase in testing in an evaluation using laboratory data. The objective for the current study was to gain a deeper understanding of whether and how practices and perceptions of GPs' HIV/sexually transmitted infection (STI) testing behaviour changed following the intervention. METHODS: We performed a mixed-methods study using questionnaires and semi-structured interviews to assess self-reported changes in HIV/STI testing by participating GPs. Questionnaires were completed by participants at the end of the final educational sessions from 2017 through 2020, and participating GPs were interviewed from January through March 2020. Questionnaire data were analysed descriptively, and open question responses were categorised thematically. Interview data were analysed following thematic analysis methods. RESULTS: In total, 101/103 participants completed questionnaires. Of 65 participants that were included in analyses on the self-reported effect of the programme, forty-seven (72%) reported it had changed their HIV/STI testing, including improved STI consultations, adherence to the STI consultation guideline, more proactive HIV testing, and more extragenital STI testing. Patients' risk factors, patients' requests and costs were most important in selecting STI tests ordered. Eight participants were interviewed and 15 themes on improved testing were identified, including improved HIV risk-assessment, more proactive testing for HIV/STI, more focus on HIV indicator conditions and extragenital STI testing, and tools to address HIV during consultations. However, several persistent barriers for optimal HIV/STI testing by GPs were identified, including HIV-related stigma and low perceived risk. CONCLUSIONS: Most GPs reported improved HIV/STI knowledge, attitude and testing, but there was a discrepancy between reported changes in HIV testing and observed increases using laboratory data. Our findings highlight challenges in implementation of effective interventions, and in their evaluation. Lessons learned from this intervention may inform follow-up initiatives to keep GPs actively engaged in HIV testing and care, on our way to zero new HIV infections