534 research outputs found
The activity of Pleurotus ostreatus extracts against pathogenic fusaria
A P. ostreatus strain, appreciated as food and for the production of nutraceuticals, was grown on a commercial substrate, dried at low temperature (<40\ub0C) and grinded in order to produce a mushroom powder. The bioactivity of the water extract conserved at 4\ub0C in the dark was then assessed on F. graminearum, F. culmorum and F. musae at different time points from production (4 hrs, 40 days, 4 months). Moreover, the effect of the extracts on trichothecene type B production was measured exploiting a F. graminearum isolate expressing GFP-tagged trichodiene synthase. This allowed to monitor the first step of toxin production using a microplate fluorimeter. While mycelial growth of F. graminearum and F. culmorum was completely blocked at 3 mg/ml, mycelial growth of F. musae was inhibited at 90%. MIC50 was measured for F. graminearum and F. culmorum at 300 micrograms/mL. A loss of the bioactivity of P. ostreaus water extract on fungal growth was observed at 40 days (-30%) and of a further -30% at 4 months. A preliminary study on the biological activities of the extract identified a strong protease activity associated to low molecular weight proteins. Their bioactivity decreased over storage time in accordance with a decreased proteolytic activity. The P. ostreatus extract modulates trichothecene production independently from the protease activity, even at concentration where no mycelium inhibition was observed (down to 0.75 micrograms/mL). Studies on the genetic determinants of the protease activity as well as the compounds able to modulate trichothecene production are ongoing
Pressure and intermittency in passive vector turbulence
We investigate the scaling properties a model of passive vector turbulence
with pressure and in the presence of a large-scale anisotropy. The leading
scaling exponents of the structure functions are proven to be anomalous. The
anisotropic exponents are organized in hierarchical families growing without
bound with the degree of anisotropy. Nonlocality produces poles in the
inertial-range dynamics corresponding to the dimensional scaling solution. The
increase with the P\'{e}clet number of hyperskewness and higher odd-dimensional
ratios signals the persistence of anisotropy effects also in the inertial
range.Comment: 4 pages, 1 figur
Limited Thermal Conductance of Metal-Carbon Interfaces
The thermal conductance for a series of metal-graphite interfaces has been experimentally measured with time-domain thermoreflectance (TDTR). For metals with Debye temperatures up to ∼400 K, a linear relationship exists with the thermal conductance values. For metals with Debye temperatures in excess of ∼400 K, the measured metal-graphite thermal conductance values remain constant near 60 MW m−2 K−1. Titanium showed slightly higher conductance than aluminum, despite the closeness of atomic mass and Debye temperature for the two metals. Surface analysis was used to identify the presence of titaniumcarbide at the interface in contrast to the aluminum and gold-carbon interfaces (with no detectablecarbide phases). It was also observed that air-cleaved graphite surfaces in contact with metals yielded slightly higher thermal conductance than graphite surfaces cleaved in vacuo. Examination of samples with scanning electron microscopy revealed that the lack of absorbed molecules on the graphite surfaceresulted in differences in transducer film morphology, thereby altering the interface conductance.Classical molecular dynamic simulations of metal-carbon nanotube thermal conductance values were calculated and compared to the TDTR results. The upper limit of metal-graphite thermal conductance is attributed to the decreased coupling at higher frequencies of the lighter metals studied, and to the decreased heat capacity for higher vibrational frequency modes
Manifestation of anisotropy persistence in the hierarchies of MHD scaling exponents
The first example of a turbulent system where the failure of the hypothesis
of small-scale isotropy restoration is detectable both in the `flattening' of
the inertial-range scaling exponent hierarchy, and in the behavior of odd-order
dimensionless ratios, e.g., skewness and hyperskewness, is presented.
Specifically, within the kinematic approximation in magnetohydrodynamical
turbulence, we show that for compressible flows, the isotropic contribution to
the scaling of magnetic correlation functions and the first anisotropic ones
may become practically indistinguishable. Moreover, skewness factor now
diverges as the P\'eclet number goes to infinity, a further indication of
small-scale anisotropy.Comment: 4 pages Latex, 1 figur
On the canonically invariant calculation of Maslov indices
After a short review of various ways to calculate the Maslov index appearing
in semiclassical Gutzwiller type trace formulae, we discuss a
coordinate-independent and canonically invariant formulation recently proposed
by A Sugita (2000, 2001). We give explicit formulae for its ingredients and
test them numerically for periodic orbits in several Hamiltonian systems with
mixed dynamics. We demonstrate how the Maslov indices and their ingredients can
be useful in the classification of periodic orbits in complicated bifurcation
scenarios, for instance in a novel sequence of seven orbits born out of a
tangent bifurcation in the H\'enon-Heiles system.Comment: LaTeX, 13 figures, 3 tables, submitted to J. Phys.
Disease activity and damage in juvenile idiopathic arthritis: Methotrexate era versus biologic era
Objective: To compare the long-term disease state, in terms of activity and damage, of children with juvenile idiopathic arthritis (JIA) who had their disease onset in methotrexate (MTX) or biologic eras. Methods: Patients were included in MTX or biologic era cohort depending on whether their disease presentation occurred before or after January 2000. All patients had disease duration 65 5 years and underwent a prospective cross-sectional assessment, which included measurement of disease activity and damage. Inactive disease (ID) and low disease activity (LDA) states were defined according to Wallace, JADAS10, and cJADAS10 criteria. Articular and extraarticular damage was assessed with the Juvenile Arthritis Damage Index (JADI). Results: MTX and biologic era cohorts included 239 and 269 patients, respectively. Patients were divided in the "functional phenotypes" of oligoarthritis and polyarthritis. At cross-sectional visit, patients in the biologic era cohort with either oligoarthritis or polyarthritis had consistently higher frequencies of ID and LDA by all criteria. The measurement of disease damage at cross-sectional visit revealed that the frequency of impairment of > 1 JADI-Articular items was higher in MTX than in biologic era cohort (17.6% versus 11% in oligoarthritis and 52.6% versus 21.8% in polyarthritis). Likewise, frequency of involvement of > 1 JADI-Extraarticular items was higher in the MTX than in the biologic era cohort (26.5% versus 16.2% in oligoarthritis and 31.4% versus 13.5% in polyarthritis). Conclusion: Our study provides evidence of the remarkable outcome improvement obtained with the recent therapeutic advance in JIA
Temporal stability of stimulus representation increases along rodent visual cortical hierarchies
Cortical representations of brief, static stimuli become more invariant to identity-preserving transformations along the ventral stream. Likewise, increased invariance along the visual hierarchy should imply greater temporal persistence of temporally structured dynamic stimuli, possibly complemented by temporal broadening of neuronal receptive fields. However, such stimuli could engage adaptive and predictive processes, whose impact on neural coding dynamics is unknown. By probing the rat analog of the ventral stream with movies, we uncovered a hierarchy of temporal scales, with deeper areas encoding visual information more persistently. Furthermore, the impact of intrinsic dynamics on the stability of stimulus representations grew gradually along the hierarchy. A database of recordings from mouse showed similar trends, additionally revealing dependencies on the behavioral state. Overall, these findings show that visual representations become progressively more stable along rodent visual processing hierarchies, with an important contribution provided by intrinsic processing
Functional Living Skills: A Non-Immersive Virtual Reality Training for Individuals with Major Neurocognitive Disorders
The loss of functional living skills (FLS) is an essential feature of major neurocognitive
disorders (M-NCD); virtual reality training (VRT) offers many possibilities for improving FLS in
people with M-NCD. The aim of our study was to verify the effectiveness of a non-immersive VRT on
FLS for patients with M-NCD. VRT was carried out for 10 to 20 sessions, by means of four 3D apps
developed in our institute and installed on a large touch screen. The experimental group (EG) and the
control group (CG) included 24 and 18 patients with M-NCD, respectively. They were administered
the in vivo test (in specific hospital places reproducing the natural environments) at T1 (pre-training)
and T3 (post-training); at T2, only EG was administered VRT. Statistically significant differences
between EG and CG in all the in vivo tests were found in the number of correct responses; during
VRT, the number of correct responses increased, while the execution times and the number of clues
decreased. The improvement in the in vivo tests appeared to be related to the specific VRT applied.
The satisfaction of participants with the VRT was moderate to high
A new approach to defining inactive disease, minimal disease activity and parent- and child-acceptable symptom state in juvenile idiopathic arthritis
The effect of sous vide packaging with rosemary essential oil on storage quality of fresh-cut potato
Selection of suitable raw materials and technologies are essential for the fresh-cut segment, since they represent key factors to be competitive in the modern markets. This study aimed at assessing the suitability of six early potato cultivars, grown in an experimental field, for minimal processing. In particular, the sous vide packaging method, in association with rosemary essential oil (REO), was evaluated as a strategy for the quality preservation of sliced potatoes. Physical, mechanical, chemical, microbiological and sensory characteristics were monitored in order to estimate qualitative changes of the product over refrigerated storage. Results demonstrated that the synergic use of REO and sous vide packaging had a positive effect on texture, and limited the growth of mesophilic bacteria and Enterobacteriaceae over the storage period; it also ensured a certain retention of ascorbic acid, total polyphenol content, and antioxidant activity. Hence, the proposed technological strategy could represent a valid solution for the preservation of sliced potatoes, contributing to limit, for the most suitable cultivars identified as Fontane and Marabel, the quality decrease until 11 days of cold storage
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