The Contribution of Occult Precipitation to Nutrient Deposition on the West Coast of South Africa

The Strandveld mediterranean-ecosystem of the west coast of South Africa supports floristically diverse vegetation growing on mostly nutrient-poor aeolian sands and extending from the Atlantic Ocean tens of kilometers inland. The cold Benguela current upwelling interacts with warm onshore southerly winds in summer causing coastal fogs in this region. We hypothesized that fog and other forms of occult precipitation contribute moisture and nutrients to the vegetation. We measured occult precipitation over one year along a transect running inland in the direction of the prevailing wind and compared the nutrient concentrations with those in rainwater. Occult deposition rates of P, N, K, Mg, Ca, Na, Al and Fe all decreased with distance from the ocean. Furthermore, ratios of cations to Na were similar to those of seawater, suggesting a marine origin for these. In contrast, N and P ratios in occult precipitation were higher than in seawater. We speculate that this is due to marine foam contributing to occult precipitation. Nutrient loss in leaf litter from dominant shrub species was measured to indicate nutrient demand. We estimated that occult precipitation could meet the demand of the dominant shrubby species for annual N, P, K and Ca. Of these species, those with small leaves intercepted more moisture and nutrients than those with larger leaves and could take up foliar deposits of glycine, NO3-, NH4 + and Li (as tracer for K) through leaf surfaces. We conclude that occult deposition together with rainfall deposition are potentially important nutrient and moisture sources for the Strandveld vegetation that contribute to this vegetation being floristically distinct from neighbouring nutrient-poor Fynbos vegetation

A case-only study to identify genetic modifiers of breast cancer risk for BRCA1/BRCA2 mutation carriers

Breast cancer (BC) risk for BRCA1 and BRCA2 mutation carriers varies by genetic and familial factors. About 50 common variants have been shown to modify BC risk for mutation carriers. All but three, were identified in general population studies. Other mutation carrier-specific susceptibility variants may exist but studies of mutation carriers have so far been underpowered. We conduct a novel case-only genome-wide association study comparing genotype frequencies between 60,212 general population BC cases and 13,007 cases with BRCA1 or BRCA2 mutations. We identify robust novel associations for 2 variants with BC for BRCA1 and 3 for BRCA2 mutation carriers, P < 10−8, at 5 loci, which are not associated with risk in the general population. They include rs60882887 at 11p11.2 where MADD, SP11 and EIF1, genes previously implicated in BC biology, are predicted as potential targets. These findings will contribute towards customising BC polygenic risk scores for BRCA1 and BRCA2 mutation carriers

Cardiac microinjury measured by Troponin T predicts collagen metabolism in adults aged ≥65 years with heart failure

BACKGROUND: Repeated myocardial micro-injuries lead to collagen deposition and fibrosis, thereby increasing the risk of clinical heart failure. Little is known about the longitudinal association between increases in myocardial injury and the biology of collagen synthesis and deposition. METHODS AND RESULTS: Repeated measures of highly sensitive cardiac troponin T (cTnT) were obtained in participants of the Cardiovascular Health Study (N-353; mean age=74±6 years, 52% women) at baseline and at three years follow-up. Biomarkers of collagen metabolism were obtained at follow-up and included carboxyterminal propeptide of procollagen type I (PIP), carboxyterminal telopeptide of type I collagen (CITP); and aminoterminal propeptide of procollagen III (PIIINP). Multivariable linear regression analyses were used to examine the association between baseline cTnT and changes in cTnT with collagen metabolism markers at follow-up, adjusting for demographics, heart failure status, and cardiovascular risk factors. Results indicated that cTnT increases over 3-years were significantly associated with higher levels of CITP (β=0.22, p<0.001) and PIIINP (β=0.12, p=0.035) at follow-up when adjusting for demographic, clinical and biochemical covariates including baseline cTnT. These associations were stronger in heart failure patients than in controls. CONCLUSIONS: Increases in myocardial micro-injury measured by changes in cTnT adversely affect markers of collagen metabolism. These findings are important to the biology of myocardial fibrosis and tissue repair. Serial evaluation of cTnT combined with collagen metabolism markers may further elucidate the pathophysiology of heart failure

Absolut “copper catalyzation perfected”; robust living polymerization of NIPAM: Guinness is good for SET-LRP

The controlled polymerization of N-isopropyl acrylamide (NIPAM) is reported in a range of international beers, wine, ciders and spirits utilizing Cu(0)-mediated living radical polymerization (SET-LRP). Highly active Cu(0) is first formed in situ by the rapid disproportionation of [Cu(I)(Me6-Tren)Br] in the commercial water–alcohol mixtures. Rapid, yet highly controlled, radical polymerization follows (Đ values as low as 1.05) despite the numerous chemicals of diverse functionality present in these solvents e.g. alpha acids, sugars, phenols, terpenoids, flavonoids, tannins, metallo-complexes, anethole etc. The results herein demonstrate the robust nature of the aqueous SET-LRP protocol, underlining its ability to operate efficiently in a wide range of complex chemical environments.ISSN:1759-9962ISSN:1759-995