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Gold nanoparticles are promising candidates as vehicles for drug delivery systems and could be developed into effective anticancer treatments. However, concerns about their safety need to be identified, addressed, and satisfactorily answered. Although gold nanoparticles are considered biocompatible and nontoxic, most of the toxicology evidence originates from in vitro studies, which may not reflect the responses in complex living organisms. We used an animal model to study the long-term effects of 20 nm spherical AuNPs coated with bovine serum albumin. Mice received a 1 mg/kg single intravenous dose of nanoparticles, and the biodistribution and accumulation, as well as the organ changes caused by the nanoparticles, were characterized in the liver, spleen, and kidneys during 120 days. The amount of nanoparticles in the organs remained high at 120 days compared with day 1, showing a 39% reduction in the liver, a 53% increase in the spleen, and a 150% increase in the kidneys. The biological effects of chronic nanoparticle exposure were associated with early inflammatory and fibrotic responses in the organs and were more pronounced in the kidneys, despite a negligible amount of nanoparticles found in renal tissues. Our data suggest, that although AuNPs belong to the safest nanomaterial platforms nowadays, due to their slow tissue elimination leading to long-term accumulation in the biological systems, they may induce toxic responses in the vital organs, and so understanding of their long-term biological impact is important to consider their potential therapeutic applications.

This study has proposed that organic matter transfer and transformation into and through a peatland is dominated by preferential loss of carbohydrates and the retention of lignin-like molecules. Here we used elemental analysis and thermogravimetric analysis to analyse the biomass, litter, peat soil profile, particulate organic matter, and dissolved organic matter fluxes sampled from a continental raised bog in comparison a maritime blanket bog. The macromolecular composition and thermodynamic analysis showed that in the raised bog there had been little or no transformation of the organic matter and the accumulation was rapid with comparatively little transformation with only 13% loss of cellulose by 1 m depth compared to 92% removal of cellulosic material in the blanket bog. The lack of transformation is reflected in a difference in long term carbon accumulation rates between raised and blanket bog sites. We propose that raised bogs, with their lack of a stream outfall, have high stable water tables that mean the pore water become thermodynamically closed and reactions cease higher in the peat profile than in a blanket bog where sloping sites mean a frequent flushing of pore water and discharge of water leading to fluctuating water tables, flushing of reaction products and pore spaces remaining open.

Nanoparticle (NP) pharmacokinetics significantly differ from traditional small molecule principles. From this emerges the need to create new tools and concepts to harness their full potential and avoid unnecessary risks. Nanoparticle pharmacokinetics strongly depend on size, shape, surface functionalisation, and aggregation state, influencing their biodistribution, accumulation, transformations, and excretion profile, and hence their efficacy and safety. Today, while NP biodistribution and nanoceria biodistribution have been studied often at short times, their long-term accumulation and excretion have rarely been studied. In this work, 3 nm nanoceria at 5.7 mg/kg of body weight was intravenously administrated in a single dose to healthy mice. Biodistribution was measured in the liver, spleen, kidney, lung, brain, lymph nodes, ovary, bone marrow, urine, and faeces at different time points (1, 9, 30, and 100 days). Biodistribution and urinary and faecal excretion were also studied in rats placed in metabolic cages at shorter times. The similarity of results of different NPs in different models is shown as the heterogeneous nanoceria distribution in organs. After the expectable accumulation in the liver and spleen, the concentration of cerium decays exponentially, accounting for about a 50% excretion of cerium from the body in 100 days. Cerium ions, coming from NP dissolution, are most likely excreted via the urinary tract, and ceria nanoparticles accumulated in the liver are most likely excreted via the hepatobiliary route. In addition, nanoceria looks safe and does not damage the target organs. No weight loss or apathy was observed during the course of the experiments.

Marine environmental monitoring is essential to ensure that heavy-metal (HM) concentrations remain within safe limits. Most seawater analyses currently consider sediment or water samples, but this approach does not apply to rocky substrates, where water samples can only indicate immediate contamination. We used two common Mediterranean algae species, Cystoseira compressa and Ericaria mediterranea, as bioindicators living in the intertidal zone on rocky substrates along the seacoast. HM concentrations were assessed over a one-year period in the perennial base crust and in the seasonal frond, considering marine sites characterised by different contamination risks. Both algae showed that HMs accumulate mainly in the perennial base rather than in the seasonal frond. Furthermore, the algae species always showed a different order of bioaccumulation factors: Cd > Ni > Pb > Cr > Cu > Mn > Zn for the frond and Pb > Cr > Ni > Cd > Mn > Cu > Zn for the base. Our study shows that C. compressa and E. mediterranea accumulate HM consistently with the types of sites analysed and differentially with respect to the part of the thallus. These results demonstrate that these algae can be effectively used as reliable bioindicators to assess the presence of HM in marine environments with rocky substrates, providing both short- and long-term monitoring.

Wetlands that develop peat are a globally significant pool of soil carbon. While some wetland types such as bogs and fens are well characterized by the consistent development of carbon-rich peat, swamps soils are more variable both in terms of their carbon densities and accretion rates. Subcategorizing swamps by forest type may be a useful way of understanding this variability. Here we provide a case study of carbon accumulation in two distinct forest stands of Greenock Swamp located in the Great Lakes – St Lawrence mixed forest region in Bruce County, Ontario, Canada: Acer - Fraxinus (maple-ash) swamp (i.e., broad-leaf swamp) prevalent across the site, and a Thuja occidentalis (cedar) swamp stand (i.e., needle-leaf swamp). Organic matter and organic carbon contents were analyzed among seven broad-leaf swamp soil cores and one needle-leaf swamp core collected from Greenock Swamp. The broad-leaf swamp cores had peat depths ranging from 18–60 cm with a mean organic matter content of 54% and an organic carbon content of 34% of dry mass. The needle-leaf swamp core had at least 4 m of almost homogeneous peat with a mean organic matter content of 89%. Radiocarbon dating indicates that the broad-leaf swamp accumulates peat episodically, but can contain organic matter thousands of years old; the needle-leaf swamp shows continuous peat accumulation since the Middle Holocene. While broad-leaf swamp soils contain lower carbon stocks than needle-leaf swamp soils, they extend over large areal extents at Greenock Swamp and elsewhere in the temperate zone and contain important pools of recalcitrant organic matter, in some cases thousands of years old. Thus, both swamp types need to be considered to fully represent the carbon pools and potential sink of temperate wetlands.

Fire can play an important role in peatlands by modifying plant communities and carbon (C) stocks. However, baseline disturbance data on peatland fire history are lacking in the hemi-boreal region. We sampled 29 peatlands in northern Michigan, Wisconsin, and Minnesota and used peat core records, radiocarbon dating, and infrared spectrometry to identify and date past fire events in 4 major hemi-boreal peatland ecotypes including open poor fens, treed poor fens, forested poor fens, and forested rich fens. In this region all types of poor fens had widely variable fire frequencies between sites. The poor fens experienced 2.1 fires per thousand years, or once every 476 years, on average, while the rich fens experienced almost no fire. Overall C stocks ranged from 10.1 to 263.3 kg C m−2 with a mean of 94.6 and median of 90.5 kg C m−2. The long-term apparent rate of carbon accumulation (LARCA) varied between 10–45 g m−2 y−1 with an average of 28 g m−2 y−1. We found a significant negative relationship between fire frequency and LARCA. Our research indicates that fire frequency is not consistent across peatland types and increases in fire frequency will likely diminish peat C stocks. These findings provide a historical context for management decisions concerning wildland fires and their consequences for ecosystem C storage in hemi-boreal peatlands.

Despite their importance as globally significant carbon (C) stores, basic knowledge of post-glacial peatland history and C accumulation are lacking for the Canadian Boreal Shield and James Bay Lowland (JBL) of central and northern Ontario, Canada. Radiocarbon dates, plant macrofossil analysis, and soil C estimates from an eight-core transect of the JBL and surrounding regions are used to reconstruct the timings and patterns of fen to bog transitions, and the ranges and patterns of long-term apparent rate of C accumulation (LARCA). Peatland initiation lagged the retreat of the Laurentide ice sheet, the drainage of glacial lakes, and isostatic uplift by 810–6050 years. Transition from Carex-dominated fen to Sphagnum-dominated bog had a median timing of 3500 years following peatland establishment and ranged from 640 to 6970 years. LARCA was variable geographically and over time with median values ranging from 13.4 to 31.6 g C/m2/yr. LARCA anomalies were generally high ~6.1 kyr (kyr = 1000 calibrated years before present (cal. yr BP)) for southern sites, and ~2.5 kyr for the most northern sites, and may be associated with elevated moisture as inferred from a brief review of regional proxy reconstructions. Some sites displayed high LARCA anomalies, changes in plant ecology, or southern site initiation, which may have also been driven by a moist Hypsithermal Period occurring ~4.5 kyr. LARCA increases were not generally associated with high-temperature anomalies during the warm ‘Medieval Climate Anomaly’ compared with the cooler ‘Little Ice Age’; however, there is evidence that the establishment of modern permafrost during the late-Holocene negatively affected C accumulation.

Ombrotrophic peatlands (bogs) act as important terrestrial sinks of organic carbon (C). These ecosystems are widespread in coastal maritime regions of eastern Canada. This study aims to evaluate and compare Holocene peatland C dynamics between two maritime ecoclimatic regions along the St. Lawrence North Shore. The investigated bogs are located on two postglacial deltas along the Estuary (Baie-Comeau) and the Gulf of St Lawrence (Havre-St-Pierre) in eastern Quebec. Long-term apparent rates of C accumulation (LORCA) are calculated for eight peat cores, and temporal variations in C accumulation are compared between six peatlands. Our data suggest that long-term C sequestration is affected by a constant anoxic decay, but the LORCA are considerably lower in Havre-St-Pierre (16−46 g C/m2/yr) than in Baie-Comeau (53−68 g C/m2/yr). The interactions between water table levels, peat humification and C accumulation are also evaluated and suggest an influence of internal (autogenic) processes and feedbacks. The bogs of the two regions show distinct patterns of C sequestration and different sensitivities to climate especially during the late Holocene. These results show that in spite of the internal influences, the regional climate has exerted a pervasive control on primary production in these peatlands over the Holocene.

In many mountainous regions, winter precipitation accumulates as snow that melts in the spring and summer, which provides water to one billion people globally. Climate warming and earlier snowmelt compromise this natural water storage. Although snowpack trend analyses commonly focus on the snow water equivalent (SWE), we propose that trends in the accumulation season snowmelt serve as a critical indicator of hydrological change. Here we compare long-term changes in the snowmelt and SWE from snow monitoring stations in western North America and find 34% of stations exhibit increasing winter snowmelt trends (P < 0.05), a factor of three larger than the 11% showing SWE declines (P < 0.05). Snowmelt trends are highly sensitive to temperature and an underlying warming signal, whereas SWE trends are more sensitive to precipitation variability. Thus, continental-scale snow water resources are in steeper decline than inferred from SWE trends alone. More winter snowmelt will complicate future water resource planning and management.Mountain snowpack declines are often tracked using snow water equivalent trends sensitive to highly variable precipitation. Observational work proposes temperature-driven daily snowmelt during the accumulation season as an alternative metric, with increases that are three times more widespread.

Background Use of a claims-based index to identify persons with physical function impairment and at risk for long-term institutionalization would facilitate population health and comparative effectiveness research. The JEN Frailty Index [JFI] is comprised of diagnosis domains representing impairments and multimorbid clusters with high long-term institutionalization [LTI] risk. We test the index’s discrimination of activities-of-daily-living [ADL] dependency and 1-year LTI and mortality in a nationally representative sample of over 12,000 Medicare beneficiaries, and compare long-term community survival stratified by ADL and JFI. Methods 2004 U.S. National Long-Term Care Survey data were linked to Medicare, Minimum Data Set, Veterans Health Administration files and vital statistics. ADL dependencies, JFI score, age and sex were measured at baseline survey. ADL and JFI groups were cross-tabulated generating likelihood ratios and classification statistics. Logistic regression compared discrimination (areas under receiver operating characteristic curves), multivariable calibration and accuracy of the JFI and, separately, ADLs, in predicting 1-year outcomes. Hall-Wellner bands facilitated contrasts of JFI- and ADL-stratified 5-year community survival. Results Likelihood ratios rose evenly across JFI risk categories. Areas under the curves of functional dependency at ≥3 and ≥ 2 for JFI, age and sex models were 0.807 [95% c.i.: 0.795, 0.819] and 0.812 [0.801, 0.822], respectively. The area under the LTI curve for JFI and age (0.781 [0.747, 0.815]) discriminated less well than the ADL-based model (0.829 [0.799, 0.860]). Community survival separated by JFI strata was comparable to ADL strata. Conclusions The JEN Frailty Index with demographic covariates is a valid claims-based measure of concurrent activities-of-daily-living impairments and future long-term institutionalization risk in older populations lacking functional information.