Aluminium release from acidic forest soil following deforestation and maize cultivation in Ghana, West Africa

Acidic tropical soils often have high Al3+ concentrations in soil solutions, which can be toxic to plants and, thereby, reduce agricultural yields. This study focuses on the impact of deforestation and cultivation on the short and long-term Al geochemistry of acidic soils in Ghana, West Africa. Site-specific investigations were made at two sites covered with forest and one site cultivated with maize (Zea mays L.). The capacity of soil to resist acidification was investigated in a leaching experiment and the corresponding release of aluminium quantified. Field results revealed a significant aacidification and Al mobility in the root zone of the cultivated site as compared to the forest sites. The leaching experiment showed that further acidification would significantly enhance Al-release and, consequently, the presence of Al3+ in soil solution. It is concluded that deforestation and cultivation in the study area has resulted in increasing levels of Al3+ and a lowering of the soils capacity to resists further acidification. This may be critical in relation to land-use management and long-term agricultural productions

Potential Activity of Subglacial Microbiota Transported to Anoxic River Delta Sediments

The Watson River drains a portion of the SW Greenland ice sheet, transporting microbial communities from subglacial environments to a delta at the head of Søndre Strømfjord. This study investigates the potential activity and community shifts of glacial microbiota deposited and buried under layers of sediments within the river delta. A long-term (12-month) incubation experiment was established using Watson River delta sediment under anaerobic conditions, with and without CO2/H2 enrichment. Within CO2/H2-amended incubations, sulphate depletion and a shift in the microbial community to a 52% predominance of Desulfosporosinus meridiei by day 371 provides evidence for sulphate reduction. We found evidence of methanogenesis in CO2/H2-amended incubations within the first 5 months, with production rates of ~4 pmol g−1 d−1, which was likely performed by methanogenic Methanomicrobiales- and Methanosarcinales-related organisms. Later, a reduction in methane was observed to be paired with the depletion of sulphate, and we hypothesise that sulphate reduction out competed hydrogenotrophic methanogenesis. The structure and diversity of the original CO2/H2-amended incubation communities changed dramatically with a major shift in predominant community members and a decline in diversity and cell abundance. These results highlight the need for further investigations into the fate of subglacial microbiota within downstream environments

Direct current (DC) resistivity and Induced Polarization (IP) monitoring of active layer dynamics at high temporal resolution

With permafrost thawing and changes in active layer dynamics induced by climate change, interactions between biogeochemical and thermal processes in the ground are of great importance. Here, active layer dynamics have been monitored using direct current (DC) resistivity and induced polarization (IP) measurements at high temporal resolution and at a relatively large scale at a heath tundra site on Disko Island on the west coast of Greenland (69 degrees N). At the field site, the active layer is disconnected from the deeper permafrost, due to isothermal springs in the region. Borehole sediment characteristics and subsurface temperatures supplemented the DC-IF measurements. A time-lapse DC-IP monitoring system has been acquiring at least six datasets per day on a 42-electrode profile with 0.5 m electrode spacing since July 2013. Remote control of the data acquisition system enables interactive adaptation of the measurement schedule, which is critically important to acquire data in the winter months, where extremely high contact resistances increase the demands on the resistivity meter. Data acquired during the freezing period of October 2013 to February 2014 clearly image the soil freezing as a strong increase in resistivity. While the freezing horizon generally moves deeper with time, some variations in the freezing depth are observed along the profile. Comparison with depth-specific soil temperature indicates an exponential relationship between resistivity and below-freezing temperature. Time-lapse inversions of the full-decay IF data indicate a decrease of normalized chargeability with freezing of the ground, which is the result of a decrease in the total unfrozen water and of the higher ion concentration in the pore-water. We conclude that DC-IP time-lapse measurements can non-intrusively and reliably image freezing patterns and their lateral variation on a 10-100 m scale that is difficult to sample by point measurements. In combination with laboratory experiments, the different patterns in resistivity and chargeability changes will enable the disentanglement of processes (e.g., fluid migration and freezing, advective and diffusive heat transport) occurring during freezing of the ground. The technology can be expanded to three dimensions and also to larger scale

Itch sensitization?:A systematic review of studies using quantitative sensory testing in patients with chronic itch

As well established for patients with chronic pain, patients suffering from chronic itch also exhibit signs of peripheral and central sensitization. This has been linked to parallel neuroplastic sensitization processes. However, for chronic itch, sensitization has not yet been systematically assessed, studied, and hence validated. This review (Prospero CRD42016043002) summarizes and meta-analytically evaluates whether sensory aberrations including sensitization for itch occur in chronic itch. Databases PubMed, Embase, and Cochrane Library were searched for studies investigating somatosensory sensitivity assessment by quantitative sensory testing stimuli, including experimental cutaneous chemical pruritic provocations, in patients with chronic itch from skin/neurological conditions and compared with healthy controls. Outcomes were extracted for lesional and nonlesional skin, and risk of biases were assessed. Meta-analyses were performed when sufficient quantitative data were available. Of 4667 identified articles, 46 were included and 25 were eligible for meta-analyses. Patients (66% atopic dermatitis [AD]) were found more sensitive than the controls to histamine-evoked itch in lesional skin (standardized mean difference [SMD]: 0.66 confidence interval [CI]: 0.16-1.15), but not nonlesionally (SMD: −0.26 [CI: −0.58 to 0.06]). Cowhage did not evoke more itch in nonlesional skin of patients as compared to the controls (SMD: 0.38 [CI: −0.04 to 0.81]). For numerous other chemical provocations as well as for mechanical, thermal, and electrical stimulation paradigms, results were ambiguous or based on few studies. Patients with chronic itch are only robustly sensitized to various chemical pruritic stimuli when applied lesionally. More studies on somatosensory aberrations in chronic itch conditions other than AD are needed to establish whether sensitization is robustly present across chronic itch conditions.Health and self-regulatio

Pan-Arctic soil element availability estimations

Arctic soils store large amounts of organic carbon and other elements, such as amorphous silicon, silicon, calcium, iron, aluminum, and phosphorous. Global warming is projected to be most pronounced in the Arctic, leading to thawing permafrost which, in turn, changes the soil element availability. To project how biogeochemical cycling in Arctic ecosystems will be affected by climate change, there is a need for data on element availability. Here, we analyzed the amorphous silicon (ASi) content as a solid fraction of the soils as well as Mehlich III extractions for the bioavailability of silicon (Si), calcium (Ca), iron (Fe), phosphorus (P), and aluminum (Al) from 574 soil samples from the circumpolar Arctic region. We show large differences in the ASi fraction and in Si, Ca, Fe, Al, and P availability among different lithologies and Arctic regions. We summarize these data in pan-Arctic maps of the ASi fraction and available Si, Ca, Fe, P, and Al concentrations, focusing on the top 100 cm of Arctic soil. Furthermore, we provide element availability values for the organic and mineral layers of the seasonally thawing active layer as well as for the uppermost permafrost layer. Our spatially explicit data on differences in the availability of elements between the different lithological classes and regions now and in the future will improve Arctic Earth system models for estimating current and future carbon and nutrient feedbacks under climate change (https://doi.org/10.17617/3.8KGQUN, Schaller and Goeckede, 2022).</p

Severe and ChRonic Atopic dermatitis Treatment CoHort (SCRATCH):A Danish Real-world Evidence Atopic Dermatitis Treatment Registry

Data from real-world use of new systemic treatments in atopic dermatitis (AD) is important for assessing safety and efficacy. The aim of this study is to describe the baseline characteristics of adult patients with moderate-to-severe AD enrolled in the Danish nationwide Severe and ChRonic Atopic dermatitis Treatment CoHort (SCRATCH) database, between October 2017 and August 2021. A total of 282 adult patients were included. Most (62%) were men, the median age at baseline was 43 years (interquartile range (IQR) 29–54 years), and median age at onset of AD was 1 year (IQR 0–6 years). The median Eczema Area and Severity Index at treatment initiation was 19.1 (IQR 11.9–25.7); median Patient Oriented Eczema Measure 21.0 (IQR 16.0–25.0); median Dermatology Life Quality Index 13.0 (IQR 7.0–19.0); and median itch and sleep numerical rating scale scores 8.0 (IQR 6.0–9.0) and 6.0 (IQR 4.0–8.0). Differences were found between the sexes. This registry will provide a source for future efficacy and safety studies