564 research outputs found
Montecarlo Calculations for the Moderator of the Pulsed Neutron Target of the Geel Linac. EUR 5157.
Effectiveness of distributed temperature measurements for early detection of piping in river embankments
Abstract. Internal erosion is the cause of a significant percentage of failure and
incidents involving both dams and river embankments in many countries. In the
past 20 years the use of fibre-optic Distributed Temperature Sensing (DTS) in
dams has proved to be an effective tool for the detection of leakages and
internal erosion. This work investigates the effectiveness of DTS for dike
monitoring, focusing on the early detection of backward erosion piping, a
mechanism that affects the foundation layer of structures resting on
permeable, sandy soils. The paper presents data from a piping test performed
on a large-scale experimental dike equipped with a DTS system together with a
large number of accompanying sensors. The effect of seepage and piping on the
temperature field is analysed, eventually identifying the processes that
cause the onset of thermal anomalies around piping channels and thus enable
their early detection. Making use of dimensional analysis, the factors that
influence this thermal response of a dike foundation are identified. Finally
some tools are provided that can be helpful for the design of monitoring
systems and for the interpretation of temperature data
Current evidence of MTX efficacy in childhood chronic uveitis: a systematic review and meta-analysis
Ecotoxicity of hallachrome, an unusual 1-2 anthraquinone excreted by the infaunal polychaete Halla parthenopeia: evidence for a chemical defence?
Polychaetes play a prominent role in marine systems, but little is known about their secondary metabolites compared with other benthic taxa. In the present study, we investigated the toxicity of hallachrome, an unusual 1-2 anthraquinone identified from the skin of some polychaetes, including the Mediterranean infaunal species Halla parthenopeia. Under stress conditions, this worm releases a harmful purple mucus, whose noxious compounds were still unknown. We hypothesized that hallachrome also occurs in the purple mucus, giving rise to its color and toxicity. Soon after the production of the purple exudate, H. parthenopeia also secretes a harmless, transparent mucus, which pushes away the toxic one, suggesting protective functions for the worm itself. LC-MS and H-1-NMR analyses confirmed the presence of the pigment hallachrome in the purple mucus. The average concentration of the pigment in the purple mucus was about 310 mg L-1. Ecotoxicological bioassays on representative species of bacteria, protozoans, rotifers, crustaceans (Artemia franciscana) and polychaetes (Dinophilus gyrociliatus) revealed its severe toxic effects: LC50/EC(50)values ranged from 0.11-5.67 mg L-1. Hallachrome showed higher toxicity for A. franciscana than other naturally occurring anthraquinones. Tests on encapsulated embryos of D. gyrociliatus evidenced the ability of a mucus layer to limit hallachrome diffusion, confirming the protective role of the transparent mucus. Given the information available on polychaetes anti-predator strategies, hallachrome cannot be considered a consumer deterrent. However its toxicity and wide range of activity suggest chemical defensive functions against potential competitors, parasites and/or pathogens
Non-Isothermal sloshing for space applications: from a ground-based experimental characterisation to microgravity conditions
Liquid cryogenic propellants are at the forefront of space
propulsion due to their optimal trade-off between
performance and weight (Sutton et al. 2017). As a result,
investigations on the sloshing dynamics of such fuels have
been carried out since the early 1960s. Sloshing, defined as
the movement of the free liquid surface within a reservoir
(Abramson, 1966), induces two types of undesirable effects:
(a) displacement of fuel tank’s centre of mass, which disturbs
the stability and manoeuvrability of the spacecraft; (b)
thermal mixing between the pressurised ullage and subcooled
liquid, which can generate large fluctuations in the tank
pressure, leading to structural instabilities and thrust
oscillations in the propulsive system. [...]This work is supported by the European Space Agency
(ESA) in the framework of the project number
4000129315/19/NL/MG. The authors gratefully acknowledge
the financial support of the “Fonds de la Recherche
Scientifique (F.R.S.-FNRS)” for the FRIA grant supporting
the PhD of Mr Marques.info:eu-repo/semantics/publishedVersio
The common NOD2/CARD15 variant P268S in patients with non-infectious uveitis: A cohort study
Background: The etiology of Autoimmune chronic uveitis (ACU) is still unknown; NOD2/CARD15 gene mutations are responsible for the Blau Syndrome and can induce uveitis in animal models. Presentation of the hypothesis: Aim of our study was to assess if NOD2/CARD15 variants have a role in the etiology or in the clinical course of patients with ACU, either idiopathic or associated with other inflammatory diseases. Testing the hypothesis: We consecutively enrolled 25 patients (19 pediatric and 6 adults) affected with ACU. For each patient medical history was reviewed and clinical data were recorded. Allelic and genotypic frequencies of NOD2/CARD15 variations were calculated in patients and matched with those of 25 healthy controls. The statistical analysis was performed. Fifteen patients showed the polymorphism P268S/SNP5 (SNP rs2066842) as heterozygous carriers while two patients were homozygous for the same polymorphism; one patient carried also the variant c647 18-16 TCT on intron 3, not previously reported in the literature. Statistical analysis for NOD2/CARD15 genotyping showed significant differences between patients and controls for allelic frequencies (p=0.04, OR: 4.03, 95 %; CI=1.2-13.5) but not for genotypic frequencies. We could not identify a significant phenotype-genotype correlation. Implications of the hypothesis: In our cohort of Italian patients, the NOD2/CARD15 common variant P268S/SNP5 could potentially be significantly associated with ACU
NEW SECONDARY METABOLITES IN THE AMPHINOMID FIREWORM HERMODICE CARUNCULATA
Eight betaine-derived novel compounds were found in extracts of the Mediterranean stinging fireworm Hermodice carunculata. The identification of their
structures relies on 1D and 2D NMR (Fig. 1-3) and HPLC-ESI/HRMS spectra. Two types of terminal ammonium portions A and B and a series of different alkyl
chains were identified (Fig. 4a,b). Their matching provides the structures of uncharacterized secondary metabolites, named carunculines, and their related
isomers. These molecules differ from already known trimethylammonium inflammatory compounds (i.e. complanines) isolated from another amphinomid
species, for the structures of the terminal ammonium groups (Fig. 4c) [1]. Carunculine anatomical distribution within H. carunculata was assessed by
screening through HPLC-ESI/HRMS (Fig. 5, Table 1): their occurrence was revealed in all the body parts analyzed, both involved in predator-prey interactions
[2], and mainly in the digestive apparatus. The results achieved reveal an array of different novel compounds from a chemically unknown species, improving
knowledge on Marine Animal Products with chemical and biological potential for bioprospection [3]. Overall, these data reinforce the necessity of studying
poorly-investigated taxa to expand knowledge on animal venom biology, their mechanisms of action and exploitation as promising source of drug molecule
Macrophage migration inhibitory factor gene polymorphisms in an Italian cohort of patients with Kawasaki disease
No evidence yet to change American Heart Association recommendations for poststreptococcal reactive arthritis : comment on the article by van Bemmel et al
Erratum to: Successful treatment with adalimumab for severe multifocal choroiditis and panuveitis in presumed (early-onset) ocular sarcoidosis
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