Differences and Commonalities in Physical, Chemical and Mineralogical Properties of Zanzibari Geophagic Soils

The function of human geophagy has long been questioned. We sought to test hypotheses concerning its potential physiological effects through analysis of soils and patterns in geophagy behavior. Eleven samples of geophagic soils consumed by pregnant women on Pemba Island, Zanzibar, Tanzania, were characterized according to their color, texture, major element chemistry, trace element chemistry, bulk mineralogy, and clay mineralogy. An epidemiological study (N = 2367) and ethnographic interviews (N = 57) on Pemba yielded information about geophagic behaviors and socio-demographic and biological characteristics of those who consumed earth. The soils varied widely in color, ranging from light red to white through various shades of brown and yellow, and texture ranged from clay to sand. Major element chemistry of the soils also varied greatly; most were low in Fe and Ca. Trace elements, whether of biological or non-biological significance, were uniformly low when compared with normal ranges of mineral soils. The sole commonality among the samples is that all clay fractions were dominated by a kaolin mineral: kaolinite, halloysite, or a mixture of both. Geophagy behavior also varied greatly, with one major exception: a greater proportion of pregnant women (7.1%) and young children (4.5%) consumed earth than non-pregnant women (0.2%) or men (0%). The presence of kaolin mineral in all samples, its palliative and detoxifying properties, and the highest prevalence of geophagy among those most biologically vulnerable suggest that geophagy may be a protective behavior

Adsorption of phosphate by halloysite (7 angstrom) nanotubes (HNTs)

The adsorption and retention of phosphates in soil systems is of wide environmental importance, and understanding the surface chemistry of halloysite (a common soil clay mineral) is also of prime importance in many emerging technological applications of halloysite nanotubes (HNTs). The adsorption of phosphate anions on tubular halloysite (7 angstrom) has been studied to gain a greater understanding of the mechanism and kinetics of adsorption on the surface of HNTs. Two well-characterized tubular halloysites with differing morphologies have been studied: one polygonal prismatic and one cylindrical, where the cylindrical form has a greater surface area and shorter tube length. Greater phosphate adsorption of up to 42 mu mol g(-1) is observed on the cylindrical halloysite when compared to the polygonal prismatic sample, where adsorption reached a maximum of just 15 mu mol g(-1) compared to a value for platy kaolinite (KGa-2) of 8 mu mol g(-1). Phosphate adsorption shows strong pH dependence, and the differences in phosphate sorption between the prismatic and cylindrical morphologies suggest that phosphate absorption does not occur at the same pH-dependent alumina edge sites and that the lumen may have a greater influence on uptake for the cylindrical form

Effects of Biochar on Properties of Tropical Sandy Soils Under Organic Agriculture

International audienceThis study evaluated the influences of biochar made from local agricultural wastes on sandy soils in farmer fields where biochar has been used as a soil amendment for more than three years. The major objective of this study was to gain insight into the effects of long-term biochar application on properties of sandy soil. Unamended soil properties were compared to biochar-amended soils properties using the paired samples t-test (p < 0.05). The statistical results of the study indicated that cation exchange capacity, exchangeable potassium, available phosphorus, field capacity, plant available water, water-stable aggregate size fractions (> 1 and < 0.25 mm), median aggregate size and aggregate stability were significantly different at p < 0.05. Clearly, biochar present for 3 or more years can improve soil physicochemical properties. We conclude that sandy soil properties, especially soil physical properties, are very strongly affected by biochar application combined with conservative soil management. Biochars affect both physical and biological mechanisms of soil aggregate formation because the biochar particle sizes influence the arrangement of clay on biochar and biochar grains provide a favorable microbial habitat and food source for fungi creating microorganism-biochar-soil associations which enhance water-stable aggregates and water holding capacity

Effect of north and south exposure on organic matter in high Alpine soils

The present work focuses on the subalpine range of the Italian Alps to determine the influence of aspect and consequently climate on soil humus properties and chemistry. This was done by comparing soils developing in north- and south-facing sites on siliceous parent material. The soils were investigated with respect to the total organic C and N content, C and N contents of organic matter (OM) density fractions and of labile(oxidised by H2O2) and stable (H2O2-resistant) fractions. Further characterisation of OM and the different fractions was performed with Diffuse Reflection Infrared Fourier Transform (DRIFT), Scanning Electron Microscopy/Electron Diffuse Scattering (SEM/EDS) and radiocarbon dating. The soils at north-facing slopes had a higher OM content. Density measurements and the H2O2 fractionation proved that this higher content was primarily due to a more pronounced accumulation of weakly degraded, labile organic materials when compared to the south-facing slopes. Independent of the sites, a large part of OM (around 50% of OM) was fixed in the densest fraction (N2 g/cm3) which correlated well with the abundance of the H2O2-resistant fraction. The 14C ages of the latter were up to 17,000 years, reflecting the presence of stable, refractory OM and the effectiveness of organo-mineral interactions in protecting OM from decay. Podzolisation has been more intense at north-facing sites. Due to the accumulation of weakly degraded OM, eluviation of Fe and Al is strongly enhanced. High-mountain ecosystems like the Alps are very sensitive to changing environmental conditions such as global warming. Especially at cooler sites, the obtained results suggest that a warmer climate, and thus more favourable conditions for biological activity, will lead in the short- to mid-term to an increased loss of accumulated, weakly degraded OM

The influence of weathering and organic matter on heavy metals lability in silicatic, Alpine soils

We investigated the effect of organic matter and weathering on the lability and solid phase speciation of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn) in two contrasting subalpine regions in the Italian Alps. Cr, Ni and Cu could be linked to weathering. This was not the case for Pb. Since organic matter (OM) influences the solid phase speciation of heavy metals, the total organic C and N content, the C and N content of different density fractions of OM and also of the labile (oxidised by H2O2) and stable (H2O2-resistant) fractions were determined. Soil OM stocks were high and soils on north-facing slopes had more OM than the south-facing sites to which they were paired. Density measurements and the H2O2 fractionation indicated that the higher OM content on north-facing sites was due to an accumulation of weakly degraded organic material. Due to higher weathering intensity on north-facing sites, the abundance of the EDTA-extractable heavy metals was higher than on south-facing sites. All EDTA-extractable heavy metals showed a good correlation to the water-soluble phenolic concentrations which indicates that the metals were probably translocated as metalorganic complexes. Pb and Cu correlate not only to the light (density b1 g/cm3) and labile, organic fraction but also to the heavy (densityN2g/cm3) and stable fraction. High-mountain ecosystems like the Alps are sensitive to changing environmental conditions such as global warming. A warmer climate and the more favourable conditions it brings for biological activity, especially at cooler sites, will probably lead in the short- to mid-term to an increased loss of accumulated, weakly degraded OM. As the Pb and Cu content is significantly related to the labile organic matter pools, the risk exists that an increase in OM mineralisation could affect the storage capacity and mobility of these metals in soils

Is there any impact of HLA-DPB1 disparity in 10/10 HLA-matched unrelated hematopoietic SCT? Results of a French multicentric retrospective study.

International audienceWe retrospectively analyzed the impact of HLA-DPB1 mismatches in a large cohort of 1342 French patients who underwent 10/10 HLA-matched unrelated HSCT. A significant impact of HLA-DPB1 allelic mismatches (2 vs 0) was observed in severe acute GVHD (aGVHDIII-IV) (risk ratio (RR)=1.73, confidence interval (CI) 95% 1.09-2.73, P=0.019) without impact on OS, TRM, relapse and chronic GVHD (cGVHD). According to the T-cell epitope 3 (TCE3)/TCE4 HLA-DPB1 disparity algorithm, 37.6% and 58.4% pairs had nonpermissive HLA-DPB1, respectively. TCE3 and TCE4 disparities had no statistical impact on OS, TRM, relapse, aGVHD and cGVHD. When TCE3/TCE4 disparities were analyzed in the graft-vs-host or host-vs-graft (HVG) direction, only a significant impact of TCE4 nonpermissive disparities in the HVG direction was observed on relapse (RR=1.34, CI 95% 1.00-1.80, P=0.048). In conclusion, this French retrospective study shows an adverse prognosis of HLA-DPB1 mismatches (2 vs 0) on severe aGVHD and of nonpermissive TCE4 HVG disparities on relapse after HLA-matched 10/10 unrelated HSCT.Bone Marrow Transplantation advance online publication, 3 November 2014; doi:10.1038/bmt.2014.253

Comparison of different methods of obtaining a resilient organic matter fraction in Alpine soils

Soil organic matter (SOM) may give precious information about the age of soil landscapes and, thus, can contribute to decipher geomorphic surface dynamics. We tested five methods of isolating the oldest possible stable organic matter of 2 soil profiles developed on a Pleistocene morainic paragneiss substratum in an Alpine environment in northern Italy. Before and after the individual treatments, the organic fraction was dated with 14C. The first two methods consist of the oxidation of organic matter with 10% hypochlorite (NaOCl), followed by dissolution of minerals with 10% hydrofluoric acid (HF) or 1 M aqua regia. Methods 3 and 4 were similar to the first two but with a changed order of the treatments (chemical oxidation as the last step). Method 5 consisted only of a treatment with hydrogen peroxide (H2O2) for 7 days. Methods 1–4 enabled, in theory, the separation of labile, mineral-protected and recalcitrant SOM fractions. With method 5 only two different fractions can be discerned, i.e. a labile one and a stable one. The lowest ages for each soil were obtained with methods 1–3 (5176 and 8835 cal BP). Higher ages were obtained with method 4 (aqua regia and NaOCl). In general, methods 1–4 showed increasing ages with increasing soil depth. The H2O2 treatment, however, left behind an organic fraction with the highest ages of up to 17,000 cal BP in the topsoil and decreasing ages with soil depth. In general, the 14C ages of the treatment-resistant fraction increased in the order: untreated samples < method 3 (HF + NaOCl) ≤ method 1 (NaOCl + HF) ≈ method 2 (NaOCl + aqua regia) < method 4 (aqua regia + NaOCl) < method 5 (H2O2). Before and after the individual treatments, the fractions were analysed for their C and N content, functional groups were measured with FT-IR and complementary information was obtained with SEM-EDS. The changes in functional groups before and after the treatment with methods 1 and 3 were not very distinct. NaOCl was a too weak reagent to oxidise all labile organic matter in soils. It seems to work more or less properly only in soils with a low OC content. The use of HF produced artefacts such as the precipitation of cryolite. This could also influence organic matter (co-precipitation) and finally its age. HF treatment destroyed kaolinite and attacked quartz but did not have a great deal of effect on other phyllosilicates like mica. The subdivision of OM into a labile, mineral-protected and recalcitrant fraction using NaOCl and HF was consequently far from being precise. Consequently, these methods might be considered questionable. About 90% of organic C was oxidised with H2O2 (method 5) but only 60% of N removed. The remaining organic matter was enriched in nitrogen with a C/N ratio between 3 and 10, aliphatic, aromatic and amide compounds. H2O2 isolated the oldest and most stable OM pool. Our results indicate that the isolated organic matter after the H2O2 treatment can probably be used to estimate the age of the earliest formation of Holocene/Pleistocene-aged Alpine soils. The obtained ages corresponded well with the maximum age of charcoal fragments and the geomorphologic settings — in particular the end of the Egesen-equivalent glacial state and the oldest Dryas

The EKiTE network (epidemiology in kidney transplantation - a European validated database): an initiative epidemiological and translational European collaborative research

BACKGROUND: Kidney transplantation is considered to be the treatment of choice for people with end-stage renal disease (ESRD). However, due to the shortage of available organs and the increase in the ESRD prevalence in Europe, it is essential to improve transplantation outcomes by studying the related prognostic factors. Today, there is no European registry collecting data to perform such clinical epidemiology studies. MAIN BODY: Entitled EKiTE, for European cohort for Kidney Transplantation Epidemiology, this prospective and multicentric cohort includes patients from Spanish (Barcelona), Belgian (Leuven), Norwegian (Oslo) and French (Paris Necker, Lyon, Nantes, Nancy, Montpellier, Nice and Paris Saint Louis) transplantation centers and currently contains 13,394 adult recipients of kidney (only) transplantation from 2005 and updated annually. A large set of parameters collected from transplantation until graft failure or death with numbers of post-transplantation outcomes. The long-term follow-up and the collected data enable a wide range of possible survival and longitudinal analyses. CONCLUSION: EKiTE is a multicentric cohort aiming to better assess the natural history of the ESRD in European kidney transplant recipients and perform benchmarking of clinical practices. The data are available for clinical epidemiology studies and open for external investigators upon request to the scientific council. Short-term perspectives are to extend EKITE network to other European countries and collect additional parameters in respect of the common thesaurus.status: publishe