19,432 research outputs found
Orafo senese. Reliquiario a pisside, fine del XIV secolo
No full textNel contributo si prende in considerazione il reliquiario a pisside, in argento, dello Spedale di Santa Maria della Scala che un tempo conteneva le reliquie di San Quirico e San Crisostomo facenti parte, entrambe, di quelle acquisite dallo Spedale il 28 maggio 1359. Si confronta l'opera con altri manufatti senesi come il reliquiario di San Mamiliano in Valli attribuito (Cioni E. 2010) a Mariano d'Agnolo Romanelli. Se ne propone la datazione ancora entro il Trecento
Maestro del pastorale di San Galgano. Pisside, secondo decennio del XIV secolo.
No full textNel contributo si analizza la pisside del Museo Diocesano di Pienza , testimonianza figurativa di grande interesse in quanto fa parte di un nucleo di oggetti, collegati da una sorprendente affinità stilistica, tutti quanti in rame dorato e ornati esclusivamente con smalti champlevés a figure risparmiate. Tale nucleo è stato riferito (Cioni E., 1998) all'attività di un orafo, non ancora identificato storicamente, attivo nel primo Trecento, per il quale si è proposto il nome di Maestro del Pastorale di San Galgano. Si sottolinea come alla qualificata produzione di quest'orafo abbiano guardato con attenzione, negli ultimi decenni del Trecento, orafi come Mariano d'Agnolo Romanelli
Composition of the essential oils from leafy parts of the shoots, flowers and fruits of Eryngium amethystinum from Amiata Mount (Tuscany, Italy)
No full textThe essential oils obtained from the leafy parts of the shoots, inflorescences and fruits of Eryngiumnext amethystinum (Apiaceae) from Italy have been studied. The essential oil from the inflorescences was characterised by methyl-derivatives of benzaldehyde (26.4%) and by some phenylpropanoids (3.0%) such as eugenol and (E)-methyl isoeugenol. The essential oil of leafy parts of the shoots showed a higher percentage of sesquiterpenes (31.3%) than monoterpenes (20.2%). The main differences between the two essential oils can be referred to α-pinene and germacrene D: the essential oil of the inflorescences contained much more α-pinene than the other one (25.6% vs. 11.8%), while the contrary is true for germacrene D (14.5% vs. 31.3%
Volatiles emission patterns of different plant organs and pollen of Citrus limon
No full textThe volatiles emitted in vivo by different plant parts of Citrus limon (Rutaceae) have been identified by mean of head space-solid phase micro-extraction (HS-SPME) and gas chromatography coupled with mass spectrometry (GC–MS) analyses. In particular, the profiles of flower buds, mature flowers, petals, stamens, gynaecium, pericarp of unripe and ripe fruits, young and adult leaves and pollen have been examined. Furthermore, the essential oil obtained from expression of ripe pericarp was studied. Volatiles were produced in distinctive amounts by the different plant organs, creating an interesting contrast, particularly within the flower parts: the highest amount of limonene (62.5%) was emitted by gynaecium, followed by stamens (22.9%) and petals (3.1%). Pollen did not produce limonene at all. The same compound is contained in higher amounts in the young leaves than in old ones (65.3% versus 30.1%). A possible defensive role of limonene and other volatiles, mainly terpene aldehydes, produced by young leaves has been hypothesize
Aroma profile and bitter acid characterization of hop cones (Humulus lupulus L.) of five healthy and infected Polish cultivars
No full textThe characteristic hoppy aroma is directly correlated with the chemical composition of its volatile profile and essential oil. The aim of this work was to analyse the essential oils and volatile fractions of five popular Polish hop cultivars (Sybilla, Lubelski, Pulawski, Magnat and Marynka), healthy and infected by viruses and viroids by SPME and GC–MS. Hop fraction of hard resins and alpha- and beta acids were determined according to the official analytical method (modified Wöllmer method EBC 7.7 and HPLC method EBC 7.5, respectively). Hop Mosaic Virus (HpMV), Apple Mosaic Virus (ApMV), Hop Latent Viroid (HLVd) are commonly found in plants of all hop cultivars commercially produced in Poland. Monoterpenes hydrocarbons showed higher percentages in the aroma profile of infected cones (82.5%–94.3%) than in the healthy ones (81.1%–91.4%) and increased from the healthy to the infected plants, except for ‘Sybilla’ that had an opposite trend (from 90.1% in healthy to 77.9% in infected hop). Hydrogenated sesquiterpenes were the second main class of aroma constituents with major amount in healthy cones with the exception for ‘Sybilla’. Myrcene was always the most abundant chemical constituent in all the infected cultivars, except for ‘Sybilla’ (from 86.3% in infected to 74.6% in healthy plants), followed by α-humulene in four of the five cultivars except for ‘Marynka’ where (E)-β-farnesene showed higher amount. The EO yields related to the five healthy cultivars showed variations between 0.2% in ‘Lubelski’ up to 1.1% in ‘Marynka’ very similar to those observed in the five infected cultivars. Monoterpenes predominated over sesquiterpenes in healthy and infected ‘Sybilla’ and ‘Marynka’ EOs, while in healthy and infected ‘Lubelski’ and ‘Magnat’ prevailed an opposite trend. ‘Magnat’ is the only one cultivar that showed different amount of the two main classes of constituents between the healthy and infected plants (sesquiterpenes 64.6% in healthy cones and 50.5% of monoterpenes in the infected ones). Myrcene was the main constituent in all the infected EO samples (29.9%–67%), while α-humulene predominated only in three healthy cultivars (‘Lubelski’ ‘Pulawski’ and ‘Magnat’ with 34.2, 36.8, 31.0%, respectively). The content of bitter substances (α and β-acids as well as hard and soft resins) varied in healthy and infected hop plants and this behaviour was strongly dependent on the selected cultivars but differences between healthy and infected plants were not statistically significant. In conclusion virus/viroid infection seems not to interfere in a substantial way with the normal hop secondary metabolite biosynthesis, but only in the biomass yields
Anterior intraparietal cortex codes complexity of contralateral observed hand movement
No full textHuman and monkey studies clearly show that the anterior intraparietal area (AIP)
is crucial for hand-related visuomotor transformations. Human AIP activates also
during observation of hand actions, involving it in the mirror system. It is not
known, however, whether its activation can also reflect a difference in the
complexity of the observed action. In the present study we used functional
magnetic resonance imaging (fMRI) to explore the activation of human area AIP
during the observation of complex object-manipulation tasks (e.g. inserting a key
in a lock and turning it) as compared to simple tasks (whole hand grasping of an
object) executed with the left and the right hand in a first person perspective.
The results show that, in general, both complex and simple tasks produced an
activation of the fronto-parietal mirror system and that the activity of AIP in
each hemisphere was higher during observation of the contralateral hand (hand
identity effect). A Region-Of-Interest (ROI) analysis of the parietal activations
responding to hand identity showed that each AIP was more active during the
observation of complex with respect to simple tasks. In the right AIP this effect
was stronger during observation of the contralateral hand, in the left AIP was
strong during observation of both hands. This complexity-related property was not
observed in the other activated areas. These findings support the concept that
the observation of motor acts retrieves the internal representation of those same
acts in the observer's motor system (direct-matching hypothesis based on the
mirror neuron mechanism)
Reconstructing reactivity in dynamic host-guest systems at atomistic resolution: amide hydrolysis under confinement in the cavity of a coordination cage
No full textSpatial confinement is widely employed by nature to attain unique efficiency in controlling chemical reactions. Notable examples are enzymes, which selectively bind reactants and exquisitely regulate their conversion into products. In an attempt to mimic natural catalytic systems, supramolecular metal-organic cages capable of encapsulating guests in their cavity and of controlling/accelerating chemical reactions under confinement are attracting increasing interest. However, the complex nature of these systems, where reactants/products continuously exchange in-and-out of the host, makes it often difficult to elucidate the factors controlling the reactivity in dynamic regimes. As a case study, here we focus on a coordination cage that can encapsulate amide guests and enhance their hydrolysis by favoring their mechanical twisting towards reactive molecular configurations under confinement. We designed an advanced multiscale simulation approach that allows us to reconstruct the reactivity in such host-guest systems in dynamic regimes. In this way, we can characterize amide encapsulation/expulsion in/out of the cage cavity (thermodynamics and kinetics), coupling such host-guest dynamic equilibrium with characteristic hydrolysis reaction constants. All computed kinetic/thermodynamic data are then combined, obtaining a statistical estimation of reaction acceleration in the host-guest system that is found in optimal agreement with the available experimental trends. This shows how, to understand the key factors controlling accelerations/variations in the reaction under confinement, it is necessary to take into account all dynamic processes that occur as intimately entangled in such host-guest systems. This also provides us with a flexible computational framework, useful to build structure-dynamics-property relationships for a variety of reactive host-guest systems
The management of Autoimmune diseases in preconception, pregnancy and lactation
No full textAutoimmune skin diseases can occur in pregnancy, and the treatment is often required to control both maternal disease and fetal outcomes. Moreover, the control of mother's diseases and fetal health is a challenge for dermatologists because of the teratogenic effects of many drugs. So it is important to know exactly which drugs can be administrated in the different stages of pregnancy. Authors reviewing the literature and relying on daily dermatological experience agree that during pregnancy effective drug treatment of autoimmune diseases is possible with reasonable safety for the fetus/child and lactation. During pregnancy and lactation patients with autoimmune disorders should be evaluated carefully, and the benefit-risk of continued therapy should be reassessed. The points to consider presented in this review show that, despite limitations, effective drug treatment of autoimmune diseases is possible with reasonable safety for the fetus/child during pregnancy and lactation. Prior to conception it is necessary to explain to the patients what the risks of pregnancy are. It is preferred to avoid a pregnancy in active disease and replace treatment with an allowed therapy. During pregnancy it is necessary to avoid treatment with mycophenolate mofetil, cyclophosphamide and methotrexate. In some very particular cases, as life saver drug, cyclosporine and rituximab can be used. Finally, some drugs can be used monitoring the patient, in particular, systemic corticosteroid at low dosage, dapsone, azathioprine, iloprost and sildenafil
Activity of plant extracts, essential oils and pure compounds against fungi contaminating foodstuffs and causing infections in human beings and animals: a six-year experience (1995-2000)
No full textThe antifungal activity of plant extracts, essential oils and pure natural compounds has been evaluated against some fungal strains belonging to Aspergillus, Pyricularia, Fusarium, Botrytis, Candida, Saprolegnia and Microsporum genera. These fungi contaminate food-stuffs and cause infections in men and animals. Most of the tested plants belong to Lamiaceae and Asteraceae familie
- …
