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Search Results: 1 - 10 of 12103 matches for " Laura Landi "
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Dietary Phenolic Acids Act as Effective Antioxidants in Membrane Models and in Cultured Cells, Exhibiting Proapoptotic Effects in Leukaemia Cells
Laura Zambonin,Cristiana Caliceti,Francesco Vieceli Dalla Sega,Diana Fiorentini,Silvana Hrelia,Laura Landi,Cecilia Prata
Oxidative Medicine and Cellular Longevity , 2012, DOI: 10.1155/2012/839298
Abstract: Caffeic, syringic, and protocatechuic acids are phenolic acids derived directly from food intake or come from the gut metabolism of polyphenols. In this study, the antioxidant activity of these compounds was at first evaluated in membrane models, where caffeic acid behaved as a very effective chain-breaking antioxidant, whereas syringic and protocatechuic acids were only retardants of lipid peroxidation. However, all three compounds acted as good scavengers of reactive species in cultured cells subjected to exogenous oxidative stress produced by low level of H2O2. Many tumour cells are characterised by increased ROS levels compared with their noncancerous counterparts. Therefore, we investigated whether phenolic acids, at low concentrations, comparable to those present in human plasma, were able to decrease basal reactive species. Results show that phenolic acids reduced ROS in a leukaemia cell line (HEL), whereas no effect was observed in normal cells, such as HUVEC. The compounds exhibited no toxicity to normal cells while they decreased proliferation in leukaemia cells, inducing apoptosis. In the debate on optimal ROS-manipulating strategies in cancer therapy, our work in leukaemia cells supports the antioxidant ROS-depleting approach.
Insulin-Like Growth Factor 1 (IGF-1) Mediates the Effects of Enriched Environment (EE) on Visual Cortical Development
Francesca Ciucci, Elena Putignano, Laura Baroncelli, Silvia Landi, Nicoletta Berardi, Lamberto Maffei
PLOS ONE , 2007, DOI: 10.1371/journal.pone.0000475
Abstract: Enriched environment (EE) has been recently shown to affect visual cortex development and plasticity, and to prevent dark rearing effects. The factors mediating EE effects on visual cortical development and plasticity are still unclear. We have investigated whether IGF-1 is involved in mediating EE effects on the developing visual cortex. We show that EE increases the number of IGF-1 positive neurons in the visual cortex at P18. Increasing IGF-1 in the visual cortex of non-EE rats by means of osmotic minipumps implanted at P18 mimics EE effects, accelerating visual acuity development, assessed with Visual Evoked Potentials (VEPs). Blocking IGF-1 action in the visual cortex of EE rats by means of the IGF-1 receptor antagonist JB1 from P18 completely blocks EE action on visual acuity development. These results show that IGF-1 is a key factor mediating EE effects on visual cortical development. We then show that IGF-1 affects GAD65 immunoreactivity in perisomatic innervation and the condensation of Chondroitin Sulphate Proteoglycans (CSPGs) in perineuronal nets (PNNs) in the visual cortex. This suggests that IGF-1 action in mediating EE effects could be exerted through the modulation of intracortical inhibitory circuitry and PNN development.
Effects of thoraco-pelvic supports during prone position in patients with acute lung injury/acute respiratory distress syndrome: a physiological study
Davide Chiumello, Massimo Cressoni, Milena Racagni, Laura Landi, Gianluigi Li Bassi, Federico Polli, Eleonora Carlesso, Luciano Gattinoni
Critical Care , 2006, DOI: 10.1186/cc4933
Abstract: We studied 11 patients with ALI/ARDS, sedated and paralyzed, mechanically ventilated in volume control ventilation. Prone positioning with or without thoraco-pelvic supports was applied in a random sequence and maintained for a 1-hour period without changing the ventilation setting. In four healthy subjects the pressures between the body and the contact surface were measured with and without thoraco-pelvic supports. Oxygenation variables (arterial and central venous), physiologic dead space, end-expiratory lung volume (helium dilution technique) and respiratory mechanics (partitioned between lung and chest wall) were measured after 60 minutes in each condition.With thoraco-pelvic supports, the contact pressures almost doubled in comparison with those measured without supports (19.1 ± 15.2 versus 10.8 ± 7.0 cmH2O, p ≤ 0.05; means ± SD). The oxygenation-related variables were not different in the prone position, with or without thoraco-pelvic supports; neither were the CO2-related variables. The lung volumes were similar in the prone position with and without thoraco-pelvic supports. The use of thoraco-pelvic supports, however, did lead to a significant decrease in chest wall compliance from 158.1 ± 77.8 to 102.5 ± 38.0 ml/cmH2O and a significantly increased pleural pressure from 4.3 ± 1.9 to 6.1 ± 1.8 cmH2O, in comparison with the prone position without supports. Moreover, when thoraco-pelvic supports were added, heart rate increased significantly from 82.1 ± 17.9 to 86.7 ± 16.7 beats/minute and stroke volume index decreased significantly from 37.8 ± 6.8 to 34.9 ± 5.4 ml/m2. The increase in pleural pressure change was associated with a significant increase in heart rate (p = 0.0003) and decrease in stroke volume index (p = 0.0241).The application of thoraco-pelvic supports decreases chest wall compliance, increases pleural pressure and slightly deteriorates hemodynamics without any advantage in gas exchange. Consequently, we stopped their use in clinical practice.Pro
“Pubblico” e “opinione pubblica”: osservazioni su due luoghi comuni del lessico politico italiano del Settecento
Sandro Landi
Cromohs (Firenze) , 2008,
Abstract: This article deals with the issue of the emergence of the “public” and the “public opinion” in the eighteen-century’s Italian political discourse. The emergence of these categories is connected with some structural transformations in the power’s ideology, in particular with the crisis of the traditional doctrine of the “arcana imperii”. The aim of this article is to underline the divergence between this discursive reality and the public sphere as a political and cultural reality in the eighteen-century’s Italy.
Chianti-an atomic database for euv emission lines
Enrico Landi
Revista mexicana de astronomía y astrofísica , 2000,
Abstract: CHIANTI contiene un conjunto de datos at omicos y probabilidades de transici on, cuidadosamente seleccionados, para calcular el espectro de emisi on de plasmas astrof sicos. Los datos contienen niveles at omicos, longitudes de onda, fuerzas de oscilador, probabilidades A de transici on y tasas de excitaci on colisional. Se provee un conjunto de programas que usan los datos para calcular el espectro, como funci on de la temperatura y la densidad, en el rango de longitudes de onda deseado. Se ha desarrollado un grupo de programas para hacer diagn osticos de plasmas astrof sicos. Se describe la base de datos CHIANTI actualizada y algunos de los resultados m as importantes que se han obtenido con ella.
Malignant transformation of cervical ostochondroma in patient with hereditary multiple exostoses (HME): Case report and review of the literature
Journal of Solid Tumors , 2012, DOI: 10.5430/jst.v2n3p63
Abstract: Objectives: Hereditary multiple exosostes (HME) is a disorder characterized by the presence of multiple osteochondromas of the bone. Spinal involvement is rare, represent roughly 3% of cases and any portion of the vertebral body may be affected. Malignant transformation of the lesions is rare, but it is possible and is described in literature. Methods: We describe an unusual case of malignant transformation of a cervical osteochondromas arising from the articular complex, in a young girl affected by HME. The patient underwent surgery with a complete removal of the lesion, without any signs of recurrence seen at the MRI serial control at 3, 6 12 e 24 months. We analyzed the literature up to 2009 by focusing on the treatment and follow up. Results: Surgical removal is indicated for symptomatic spinal osteochondormas. The suspicion of malignant transformation is indicated by the sudden growth of the lesion after puberty, the presence of pain and the worsening of the neurological symptoms. Conclusions: In this case, radical surgery is imperative, given the close correlation with the malignant characteristics of the lesions, it is useful to have an extemporaneous histological examination. In the rare cases of malignant transformation, radical surgery is important for the prognosis and to prevent the progression of the lesions. If the complete removal is not possible, the therapy of choice is adjuvant radiotherapy.
Comparison of the Different Land Use on the Emission of Greenhouse Gases
Journal of Science and Technology of Agriculture and Natural Resources , 2010,
Abstract: An increase in the emission of greenhouse gases such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) from the soil surface to the atmosphere has been of worldwide concern over the last several decades. Carbon dioxide is recognized as a significant contributor to global warming and climatic change, accounting for 60% of total greenhouse effect. The aim of this research was to determinate the emission of greenhouse gases from different land under agricultural uses. Four types of agricultural land farm, including wheat field, canola field, citrus garden and fallow land were selected to investigate the fate of CO2 in these fields. Gas chromatography technique and close chamber method were used to analyze soil gas samples. Total carbon losses from soil in form of greenhouse gases was 4.47, 3.72, 3.38 and 1.89 Mg C ha-1 yr-1 for wheat field, canola field, citrus garden and fallow land, respectively. Total additional carbon to soil from biomass for wheat field and canola field was 4.1 and 4.6 Mg C ha-1 yr-1, respectively. ECB (ecosystem carbon budget) = ∑ C input - ∑ C output. For wheat field and canola field ECB was -0.37 and +0.88, respectively. This indicated that in wheat field carbon was lost and in canola field carbon was sequestrated. Under citrus garden due to changes in soil organic carbon form previous year has showed that carbon was sequestrated.
Spin-Hall effect with quantum group symmetry
Giovanni Landi
Physics , 2005, DOI: 10.1007/s11005-005-0040-8
Abstract: We construct a model of spin-Hall effect on a noncommutative 4 sphere with isospin degrees of freedom (coming from a noncommutative instanton) and invariance under a quantum orthogonal group. The corresponding representation theory allows to explicitly diagonalize the Hamiltonian and construct the ground state; there are both integer and fractional excitations. Similar models exist on higher dimensional noncommutative spheres and noncommutative projective spaces.
Noncommutative Spheres and Instantons
Giovanni Landi
Physics , 2003, DOI: 10.1007/11342786_1
Abstract: We report on some recent work on deformation of spaces, notably deformation of spheres, describing two classes of examples. The first class of examples consists of noncommutative manifolds associated with the so called $\theta$-deformations which were introduced out of a simple analysis in terms of cycles in the $(b,B)$-complex of cyclic homology. These examples have non-trivial global features and can be endowed with a structure of noncommutative manifolds, in terms of a spectral triple $(\ca, \ch, D)$. In particular, noncommutative spheres $S^{N}_{\theta}$ are isospectral deformations of usual spherical geometries. For the corresponding spectral triple $(\cinf(S^{N}_\theta), \ch, D)$, both the Hilbert space of spinors $\ch= L^2(S^{N},\cs)$ and the Dirac operator $D$ are the usual ones on the commutative $N$-dimensional sphere $S^{N}$ and only the algebra and its action on $\ch$ are deformed. The second class of examples is made of the so called quantum spheres $S^{N}_q$ which are homogeneous spaces of quantum orthogonal and quantum unitary groups. For these spheres, there is a complete description of $K$-theory, in terms of nontrivial self-adjoint idempotents (projections) and unitaries, and of the $K$-homology, in term of nontrivial Fredholm modules, as well as of the corresponding Chern characters in cyclic homology and cohomology.
Deconstructing Monopoles and Instantons
Giovanni Landi
Physics , 1998,
Abstract: We give a unifying description of the Dirac monopole on the 2-sphere $S^2$, of a graded monopole on a (2,2)-supersphere $S^{2,2}$ and of the BPST instanton on the 4-sphere $S^4$, by constructing a suitable global projector $p$ via equivariant maps. This projector determines the projective module of finite type of sections of the corresponding vector bundle. The canonical connection $\nabla = p \circ d$ is used to compute the topological charge which is found to be equal to -1 for the three cases. The transposed projector $q=p^t$ gives the value +1 for the charges; this showing that transposition of projectors, although an isomorphism in $K$-theory, is not the identity map. We also study the invariance under the action of suitable Lie groups.
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