71 research outputs found
Misure elettromagnetiche a basso numero di induzione e radar, da natante, per lo studio dei fondi fluviali
Sono presentati i risultati di una campagna di misure elettromagnetiche a basso numero di induzione condotte da natante su un tratto del fiume Po a Torino. I risultati, verificati con una campionamento diretto, hanno permesso di stimare la natura dei sedimenti di fondo del fium
Study of riverine deposits using electromagnetic methods at a low induction number
We conducted electromagnetic EM profiles along the Po
River in Turin, Italy. The aim of this activity was to verify the
applicability of low-induction-number EM multifrequency
soundings carried out from a boat in riverine surveys and to
determine whether this technique, which is cheaper than aircarried
surveys, could be used effectively to define the typology
of sediments and to estimate the stratigraphy below a riverbed.
We used a GEM-2 handheld broadband EM sensor
operating with six frequencies to survey the investigated
area. Ground-penetrating radar GPR, a conductivity meter,
and a time-domain reflectometer were used to estimate the
bathymetry and to measure the EM properties of the water.A
global positioning system, working in real-time kinematic
mode, tracked the route of the boat with centimetric accuracy.
We analyzed the induction number, the depth of investigation
DOI, and the sensitivity of our experimental setup by forward
modeling — varying the water depth, frequency, and
bottom-sediment resistivity. The simulations optimized the
choice of the frequencies that could be used reliably for the
interpretation. The 3406-Hz signal had a DOI in the Po River
water 27 m of 2.5 m and provided sediment resistivities
higher than 100 m.We applied a bathymetric correction to
the conductivity data using the water depths obtained from
the GPR data.We plotted amap of the river bottom resistivity
and compared this map to the results of a direct sediment
sampling campaign. The resistivity values 120–240 m
were compatible with the saturated gravel and pebbles in a
sandy matrix, which resulted from direct sampling and with
the known geology
Natural Killer Cells from Patients with Recombinase-Activating Gene and Non-Homologous End Joining Gene Defects Comprise a Higher Frequency of CD56bright NKG2A+++ Cells, and Yet Display Increased Degranulation and Higher Perforin Content.
Mutations of the recombinase Activating Genes 1 and 2 (RAG1, RAG2) in humans are associated with a broad range of phenotypes. For patients with severe clinical presentation, hematopoietic stem cell transplantation (HSCT) represents the only curative treatment, however high rates of graft failure and incomplete immune reconstitution have been observed, especially after unconditioned haploidentical transplantation. Studies in mice have shown that Rag-/- NK cells have a mature phenotype, reduced fitness and increased cytotoxicity. We aimed to analyze NK cell phenotype and function in patients with mutations in RAG and in non-homologous end joining (NHEJ) genes. Here we provide evidence that NK cells from these patients have an immature phenotype, with significant expansion of CD56bright CD16-/int CD57- cells, yet increased degranulation and high perforin content. Correlation was observed between in vitro recombinase activity of the mutant proteins, NK cell abnormalities, and in vivo clinical phenotype. Addition of serotherapy in the conditioning regimen, with the aim of depleting the autologous NK cell compartment, may be important to facilitate engraftment and immune reconstitution in patients with RAG and NHEJ defects treated by HSCT
Valuing Insect Pollination Services with Cost of Replacement
Value estimates of ecosystem goods and services are useful to justify the allocation of resources towards conservation, but inconclusive estimates risk unsustainable resource allocations. Here we present replacement costs as a more accurate value estimate of insect pollination as an ecosystem service, although this method could also be applied to other services. The importance of insect pollination to agriculture is unequivocal. However, whether this service is largely provided by wild pollinators (genuine ecosystem service) or managed pollinators (commercial service), and which of these requires immediate action amidst reports of pollinator decline, remains contested. If crop pollination is used to argue for biodiversity conservation, clear distinction should be made between values of managed- and wild pollination services. Current methods either under-estimate or over-estimate the pollination service value, and make use of criticised general insect and managed pollinator dependence factors. We apply the theoretical concept of ascribing a value to a service by calculating the cost to replace it, as a novel way of valuing wild and managed pollination services. Adjusted insect and managed pollinator dependence factors were used to estimate the cost of replacing insect- and managed pollination services for the Western Cape deciduous fruit industry of South Africa. Using pollen dusting and hand pollination as suitable replacements, we value pollination services significantly higher than current market prices for commercial pollination, although lower than traditional proportional estimates. The complexity associated with inclusive value estimation of pollination services required several defendable assumptions, but made estimates more inclusive than previous attempts. Consequently this study provides the basis for continued improvement in context specific pollination service value estimates
A Novel 19F-NMR Method for the Investigation of the Antioxidant Capacity of Biomolecules and Biofluids
A new assay for the measurement of the antioxidant capacity of biomolecules by high resolution F-19-NMR spectroscopy is presented here. This method is based on the use of trifluoroacetanilidic detectors, namely trifluoroacetanilide, N-(4-hydroxyphenyl)-trifluoroacetamide and 2-hydroxy-4-trifluoroacetamidobenzoic acid. Upon hydroxyl radical attack, such fluorinated detectors yield trifluoroacetamide and trifluoroacetic acid that can be quantitatively determined by F-19-NMR spectroscopy. Trifluoroacetamide was found to be a reliable reporter of hydroxyl radical attack on the fluorinated detectors, whereas N-(4-hydroxyphenyl)-trifluoroacetamide was found to be the most sensitive detector amongst the ones considered. Therefore, N-(4-hydroxyphenyl)-trifluoroacetamide has been used in competition experiments to assess the antioxidant capacity of a number of low and high molecular weight antioxidants. The antioxidant capacity of a given compound has been scaled in terms of an adimensional parameter, k(F), that represents the ratio between the scavenger abilities of the fluorinated detector and the competitor. k(F) values obtained for low-molecular-mass compounds fall in the range 0.17 < k(F) < 1.5 and are in good agreement with second order rate constants (k(2)(OH)) for the reaction of the antioxidant with hydroxyl radicals. The k(F) value for serum albumin is much larger (46.9) than that predicted from the reported k(2)(OH) value. This finding supports the view that the protein can very effectively scavenge hydroxyl radicals as well as secondary radicals. Human blood serum showed that its antioxidant capacity is even higher than that shown by aqueous solutions of albumin at physiologic concentration suggesting a further contribution from other macromolecular serum components
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