Uranium leaching from contaminated soil utilizing rhamnolipid, EDTA, and citric acid

Biosurfactants have recently gained attention as "green" agents that can be used to enhance the remediation of heavy metals and some organic matter in contaminated soils. The overall objective of this paper was to investigate rhamnolipid, a microbial produced biosurfactant, and its ability to leach uranium present in contaminated soil from an abandoned mine site. Soil samples were collected from two locations in northern Arizona: Cameron (site of open pit mining) and Leupp (control-no mining). The approach taken was to first determine the total uranium content in each soil using a hydrofluoric acid digestion, then comparing the amount of metal removed by rhamnolipid to other chelating agents EDTA and citric acid, and finally determining the amount of soluble metal in the soil matrix using a sequential extraction. Results suggested a complex system for metal removal from soil utilizing rhamnolipid. It was determined that rhamnolipid at a concentration of 150 mu M was as effective as EDTA but not as effective as citric acid for the removal of soluble uranium. However, the rhamnolipid was only slightly better at removing uranium from the mining soil compared to a purified water control. Overall, this study demonstrated that rhamnolipid ability to remove uranium from contaminated soil is comparable to EDTA and to a lesser extent citric acid, but, for the soils investigated, it is not significantly better than a simple water wash

A Cenozoic-style scenario for the end-Ordovician glaciation

The end-Ordovician was an enigmatic interval in the Phanerozoic, known for massive glaciation potentially at elevated CO2 levels, biogeochemical cycle disruptions recorded as large isotope anomalies and a devastating extinction event. Ice-sheet volumes claimed to be twice those of the Last Glacial Maximum paradoxically coincided with oceans as warm as today. Here we argue that some of these remarkable claims arise from undersampling of incomplete geological sections that led to apparent temporal correlations within the relatively coarse resolution capability of Palaeozoic biochronostratigraphy. We examine exceptionally complete sedimentary records from two, low and high, palaeolatitude settings. Their correlation framework reveals a Cenozoic-style scenario including three main glacial cycles and higher-order phenomena. This necessitates revision of mechanisms for the end-Ordovician events, as the first extinction is tied to an early phase of melting, not to initial cooling, and the largest δ13C excursion occurs during final deglaciation, not at the glacial apex

Management of Occupational Manganism: Consensus of an Experts' Panel

Studies and Research Projects / Report R-417, Montréal, IRSST http://www.irsst.qc.ca/en/_publicationirsst_100134.html (Lucchini R was a member of the Expert Panel

Tents, Chairs, Tacos, Kites, and Rods: Shapes and Plasmonic Properties of Singly Twinned Magnesium Nanoparticles

Nanostructures of some metals can sustain light-driven electron oscillations called localized surface plasmon resonances, or LSPRs, that give rise to absorption, scattering, and local electric field enhancement. Their resonant frequency is dictated by the nanoparticle (NP) shape and size, fueling much research geared toward discovery and control of new structures. LSPR properties also depend on composition; traditional, rare, and expensive noble metals (Ag, Au) are increasingly eclipsed by earth-abundant alternatives, with Mg being an exciting candidate capable of sustaining resonances across the ultraviolet, visible, and near-infrared spectral ranges. Here, we report numerical predictions and experimental verifications of a set of shapes based on Mg NPs displaying various twinning patterns including (101̅1), (101̅2), (101̅3), and (112̅1), that create tent-, chair-, taco-, and kite-shaped NPs, respectively. These are strikingly different from what is obtained for typical plasmonic metals because Mg crystallizes in a hexagonal close packed structure, as opposed to the cubic Al, Cu, Ag, and Au. A numerical survey of the optical response of the various structures, as well as the effect of size and aspect ratio, reveals their rich array of resonances, which are supported by single-particle optical scattering experiments. Further, corresponding numerical and experimental studies of the near-field plasmon distribution via scanning transmission electron microscopy electron-energy loss spectroscopy unravels a mode nature and distribution that are unlike those of either hexagonal plates or cylindrical rods. These NPs, made from earth-abundant Mg, provide interesting ways to control light at the nanoscale across the ultraviolet, visible, and near-infrared spectral ranges

Occurrence, Distribution and Behaviour of Beluga (Delphinapterus leucas) and Bowhead (Balaena mysticetus) Whales at the Franklin Bay Ice Edge in June 2008

Ice edges and polynyas have long been noted for their high biological productivity within the Arctic environment. In June 2008, an aggregation of belugas and bowheads was identified at the Franklin Bay ice edge in the eastern Beaufort Sea, adjacent to the Cape Bathurst polynya. We conducted five ice-edge surveys by helicopter to study the distribution and behaviour of the whales. Bowheads were sighted in significantly shallower water than belugas. In addition, we used the helicopter platform to observe behaviour. Belugas and bowheads were engaged in directed travel and diving near and under the ice. Five beluga dives were timed and found to have an average duration of 106 ± 61 s (± SD) and a range of 30 – 197 s. One bowhead under-ice dive was timed and had a duration of 417 s. The under-ice dives are consistent with feeding behaviour observed for belugas and bowheads in other ice-edge locations. We hypothesize that higher prey densities along the Franklin Bay ice edge than in the adjacent open water may attract belugas and bowheads to the ice edge in June. Further research is needed to identify the abundance and type of prey species consumed and to assess the relative energetic importance of spring ice-edge feeding to the eastern Beaufort Sea beluga and bowhead populations.Depuis longtemps, les lisières de glace et les polynies sont connues pour leur grande productivité biologique au sein de l’environnement arctique. En juin 2008, un groupement de bélugas et de baleines boréales a été repéré à la lisière de glace de la baie Franklin, dans l’est de la mer de Beaufort, lisière adjacente à la polynie du cap Bathurst. Au moyen d’hélicoptères, nous avons effectué cinq études de lisières de glace afin d’examiner la répartition des baleines de même que leur comportement. Les baleines boréales évoluaient dans des eaux beaucoup moins profondes que les bélugas. De plus, nous avons étudié le comportement des baleines à partir de la plateforme destinée aux hélicoptères. Les bélugas et les baleines boréales se déplaçaient de manière dirigée et plongeaient près de la glace et sous celle-ci. Les plongeons de bélugas ont été chronométrés, et leur durée moyenne s’établissait à 106 ± 61 s (± SD), avec une étendue de 30 – 197 s. Le plongeon sous glace d’une baleine boréale a duré 417 s. Les plongeons sous glace vont de pair avec le comportement alimentaire observé chez les bélugas et les baleines boréales d’autres emplacements en lisières de glace. Nous avançons l’hypothèse que la plus grande densité de proies le long de la lisière de glace de la baie Franklin comparativement aux eaux libres adjacentes peut attirer les bélugas et les baleines boréales à la lisière de glace en juin. Il faut pousser les recherches plus loin pour déterminer l’abondance et le type d’espècesproies consommées et pour évaluer l’importance énergétique relative de l’alimentation à la lisière de glace au printemps pour les populations de bélugas et de baleines boréales de l’est de la mer de Beaufort

Repeatability of quantitative18F-FLT uptake measurements in solid tumors: an individual patient data multi-center meta-analysis

INTRODUCTION: 3'-deoxy-3'-[18F]fluorothymidine (18F-FLT) positron emission tomography (PET) provides a non-invasive method to assess cellular proliferation and response to antitumor therapy. Quantitative18F-FLT uptake metrics are being used for evaluation of proliferative response in investigational setting, however multi-center repeatability needs to be established. The aim of this study was to determine the repeatability of18F-FLT tumor uptake metrics by re-analyzing individual patient data from previously published reports using the same tumor segmentation method and repeatability metrics across cohorts. METHODS: A systematic search in PubMed, EMBASE.com and the Cochrane Library from inception-October 2016 yielded five18F-FLT repeatability cohorts in solid tumors.18F-FLT avid lesions were delineated using a 50% isocontour adapted for local background on test and retest scans. SUVmax, SUVmean, SUVpeak, proliferative volume and total lesion uptake (TLU) were calculated. Repeatability was assessed using the repeatability coefficient (RC = 1.96 × SD of test-retest differences), linear regression analysis, and the intra-class correlation coefficient (ICC). The impact of different lesion selection criteria was also evaluated. RESULTS: Images from four cohorts containing 30 patients with 52 lesions were obtained and analyzed (ten in breast cancer, nine in head and neck squamous cell carcinoma, and 33 in non-small cell lung cancer patients). A good correlation was found between test-retest data for all18F-FLT uptake metrics (R2 ≥ 0.93; ICC ≥ 0.96). Best repeatability was found for SUVpeak(RC: 23.1%), without significant differences in RC between different SUV metrics. Repeatability of proliferative volume (RC: 36.0%) and TLU (RC: 36.4%) was worse than SUV. Lesion selection methods based on SUVmax ≥ 4.0 improved the repeatability of volumetric metrics (RC: 26-28%), but did not affect the repeatability of SUV metrics. CONCLUSIONS: In multi-center studies, differences ≥ 25% in18F-FLT SUV metrics likely represent a true change in tumor uptake. Larger differences are required for FLT metrics comprising volume estimates when no lesion selection criteria are applied

Diversity of use and local knowledge of wild edible plant resources in Nepal

Background Wild edible plants (WEP) provide staple and supplement foods, as well as cash income to local communities, thus favouring food security. However, WEP are largely ignored in land use planning and implementation, economic development, and biodiversity conservation. Moreover, WEP-related traditional knowledge is rapidly eroding. Therefore, we designed this study to fulfill a part of the knowledge gap by providing data on diversity, traditional knowledge, economic potential, and conservation value of WEP from Nepal. Methods The information was collected through focus group discussions and key informant interviews. Percentage of general utility of the plants among the study communities was evaluated using the Chi-square (χ2) test of homogeneity. High priority species were identified after consultation with the local stakeholders followed by scoring based on defined criteria. Pairwise ranking was used to assess ethnoecological knowledge to identify the threats to WEP. Results We documented 81 species belonging to Angiosperms (74), Pteridophytes (5), and Fungi (2). Most of the species were used as fruits (44 species) followed by vegetables (36). Almost half of the species (47%) were also used for purposes other than food. From the species with market value (37% of the total), 10 were identified as high priority species. Pairwise ranking revealed that WEP are threatened mostly by habitat destruction, land-use change and over-harvesting. Some of these plants are crop wild relatives and could thus be used for crop improvement. Interestingly, our study also revealed that young people who spend most of the time in the forest as herdsmen are particularly knowledgeable of wild fruit plants. Conclusion We provide empirical evidence from a relatively large area of Nepal about diversity and status of WEP, as well as methodological insights about the proper knowledge holders to consult. Regarding the unique and important knowledge they have on WEP, young people should be included when recruiting participants to ethnobotanical studies or to any type of consultation about WEP. The habit of using wild edible plants is still alive and is a traditional culinary practice that demonstrates rich traditional knowledge of local people. WEP were found to be important for livelihood as well as showing great potential for crop improvement. Priority species should be promoted for income generation activities through sustainable collection and trade. Communities should engage in minimizing the threats to these valuable resources

Sialylation of campylobacter jejuni lipo-oligosaccharides: impact on phagocytosis and cytokine production in mice

<p>Background: Guillain-Barré syndrome (GBS) is a post-infectious polyradiculoneuropathy, frequently associated with antecedent Campylobacter jejuni (C. jejuni) infection. The presence of sialic acid on C. jejuni lipo-oligosaccharide (LOS) is considered a risk factor for development of GBS as it crucially determines the structural homology between LOS and gangliosides, explaining the induction of cross-reactive neurotoxic antibodies. Sialylated C. jejuni are recognised by TLR4 and sialoadhesin; however, the functional implications of these interactions in vivo are unknown.</p> <p>Methodology/Principal Findings: In this study we investigated the effects of bacterial sialylation on phagocytosis and cytokine secretion by mouse myeloid cells in vitro and in vivo. Using fluorescently labelled GM1a/GD1a ganglioside-mimicking C. jejuni strains and corresponding (Cst-II-mutant) control strains lacking sialic acid, we show that sialylated C. jejuni was more efficiently phagocytosed in vitro by BM-MΦ, but not by BM-DC. In addition, LOS sialylation increased the production of IL-10, IL-6 and IFN-β by both BM-MΦ and BM-DC. Subsequent in vivo experiments revealed that sialylation augmented the deposition of fluorescent bacteria in splenic DC, but not macrophages. In addition, sialylation significantly amplified the production of type I interferons, which was independent of pDC.</p> <p>Conclusions/Significance: These results identify novel immune stimulatory effects of C. jejuni sialylation, which may be important in inducing cross-reactive humoral responses that cause GBS</p&gt

In vivo P-glycoprotein function before and after epilepsy surgery

Objectives: To study the functional activity of the multidrug efflux transporter P-glycoprotein (Pgp) at the blood-brain barrier of patients with temporal lobe epilepsy using (R)-[11C]verapamil (VPM)-PET before and after temporal lobe surgery to assess whether postoperative changes in seizure frequency and antiepileptic drug load are associated with changes in Pgp function. Methods: Seven patients with drug-resistant temporal lobe epilepsy underwent VPM-PET scans pre- and postsurgery. Patients were followed up for a median of 6 years (range 4–7) after surgery. Pgp immunoreactivity in surgically resected hippocampal specimens was determined with immunohistochemistry. Results: Optimal surgical outcome, defined as seizure freedom and withdrawal of antiepileptic drugs, was associated with higher temporal lobe Pgp function before surgery, higher Pgp-positive staining in surgically resected hippocampal specimens, and reduction in global Pgp function postoperatively, compared with nonoptimal surgery outcome. Conclusions: The data from our pilot study suggest that Pgp overactivity in epilepsy is dynamic, and complete seizure control and elimination of antiepileptic medication is associated with reversal of overactivity, although these findings will require confirmation in a larger patient cohort