Split-root labelling to investigate 15N rhizodeposition by Pinus sylvestris and Picea abies*

We investigated the transfer of ¹⁵N into the soil via ¹⁵N uptake and release by tree roots, which involves the principles of the split-root technique. One half of the root system received an injection of (¹⁵NH₄)₂SO₄ and the other half equivalent amounts of (NH₄)₂SO₄ at ¹⁵N natural abundance level. ¹⁵N was transferred from one side of the root system (¹⁵N side) to the other side (¹⁴N side) and released into the soil. The method was conducted with Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies [L.] Karst). Two concentration levels of (NH₄)₂SO₄ were used, corresponding with annual N deposition in the Netherlands (30 kg N ha^–1) and a twelfth of that (2.5 kg N ha^?1). Samples were taken 3 and 6 weeks after labelling and divided into needles?+?stem, roots, rhizosphere and bulk soil. Already 3 weeks after labelling, Scots pine took up 23.7?% of the low and 9.1?% of the high amounts of ¹⁵N, while Norway spruce took up 21.5 and 32.1?%, respectively. Both species transported proportions of ¹⁵N to the rhizosphere (0.1–0.2?%) and bulk soil (0.3–0.9?%). The method is a useful tool to investigate the fate of root-derived N in soils, for example, for the formation of stable forms of soil organic matter.     

Bifluoride Ion Mediated SuFEx Trifluoromethylation of Sulfonyl Fluorides and Iminosulfur Oxydifluorides

SuFEx is a new‐generation click chemistry transformation that exploits the unique properties of S?F bonds and their ability to undergo near‐perfect reactions with nucleophiles. We report here the first SuFEx‐based procedure for the efficient synthesis of pharmaceutically important triflones and bis(trifluoromethyl)sulfur oxyimines from sulfonyl fluorides and iminosulfur oxydifluorides, respectively. The new process involves rapid S?F exchange with trifluoromethyltrimethylsilane (TMSCF₃) upon activation by potassium bifluoride in anhydrous DMSO. The reaction tolerates a wide selection of substrates and proceeds under mild conditions without need for chromatographic purification. A tentative mechanism is proposed involving nucleophilic displacement of S?F by the trifluoromethyl anion via a five‐coordinate intermediate. The utility of late‐stage SuFEx trifluoromethylation is demonstrated through the synthesis and selective anticancer properties of a bis(trifluoromethyl)sulfur oxyimine.     

Psychological distress and breast self-examination frequency in women at increased risk for hereditary or familial breast cancer

BACKGROUND: The Magnetic Resonance Imaging Screening study evaluates the efficacy and psychological impact of a surveillance program for women at increased risk for hereditary or familial breast cancer in the Netherlands. Surveillance consists of biannual physical examination, annual mammography, annual MRI and monthly breast self-examination (BSE). OBJECTIVE: To examine the association between psychological distress and reported BSE frequency. METHODS: Two months prior to surveillance demographics, BSE frequency, general distress (Hospital Anxiety and Depression Scale and the somatic scale of the Symptom Checklist-90) and breast cancer-specific distress (Impact of Event Scale) were assessed in 316 women (mean age 40.5 years, range 21-63 years). RESULTS: The majority (57%) reported performing monthly BSE. Ten percent reported never performing BSE, 20% less frequently than once a month and 13% at least once a week. Women below the age of 40 who examined their breasts more frequently than recommended (i.e. at least once a week) were shown to be significantly more distressed than the other women in the sample (p = 0.03). These women represented 15% of all the women below the age of 40 years in our study sample. CONCLUSION: Higher breast cancer-specific distress scores were observed among younger women who examined their breasts at least once a week. It is important for physicians to be aware of this hypervigilant behaviour, especially since it is correlated with breast cancer-specific distress.