131 research outputs found
Si può veramente uscire da sé? Viveiros de Castro con Deleuze, Ricœur con Geertz
No full textNel dibattito antropologico contemporaneo ha assunto particolare rilievo la cosiddetta "svolta ontologica". Il presente articolo si propone di analizzare criticamente questo approccio nella variante "brasiliana" proposta da Eduardo Viveiros de Castro. Ci si interroga in particolare sulla possibilità di parlare in proposito di una forma di ermeneutica, intesa come radicale processo di divenire-altro in relazione ad una polivocità di mondi, nonostante il veto posto dall'autore nei confronti del concetto di interpretazione. Nella seconda parte dell’articolo, si propone poi una ripresa del pensiero di Geertz e Ricœur, per confrontare l’antropologia ontologica con quella interpretativa classica, per cui il lavoro antropologico costituisce un lungo percorso che alla fine però riconduce sempre a casa, per quanto cambiati. Nell’ultima sezione, infine, si cerca di mostrare come un confronto tra queste forme di ermeneutica diametralmente contrapposte possa essere fecondo e come esse trovino un punto d’incontro nella comune preoccupazione per la ricerca di una postura di apertura nei confronti dell’alterità
Comprehensive Thermodynamic Evaluation of the Natural Gas-Fired Allam Cycle at Full Load
No full textIn this study, thermodynamic modeling and simulations were used to optimize the design point performance of the Allam cycle. The topic fits perfectly with the strategies for power sector decarbonization toward net zero emission. In fact, it offers an environmentally friendlier alternative to natural gas combined cycle (NGCC) plants. The focus is on oxyfuel combustion that, combined with supercritical CO2 (sCO2) stream as working fluid, produces high-purity CO2, electricity, and water by means of a highly recuperated Brayton cycle. The former is ready for sequestration, pipeline injection, or other applications, such as enhanced oil recovery or industrial processes. Being designed within the last decade, large-scale plants are poorly documented in the published literature and not yet ready for operation. Accordingly, a thermodynamic model was developed for a net power (Pn) output of 300 MW. After validation against the little data available from academic studies, simulation sets were conceived to assess the impact of main process parameters on cycle efficiency. To that end, operating conditions of the compressor, turbine, and air separation unit (ASU) were varied in a parametric analysis, preparatory to performance optimization. For the chosen layout, the maximum net electric efficiency (ηel,n) was found to be 50.4%, without thermal recovery from ASU
Off-Design Performance Modeling of the Natural Gas-Fired Allam Cycle
No full textThis work focuses on modeling the performance of the natural gas-fired Allam cycle under off-design conditions. Key thermodynamic parameters, such as turbine inlet pressure (TIP), turbine inlet temperature (TIT), and turbine outlet temperature (TOT), were evaluated at part-load and varying environmental conditions. In the former case, different control strategies were implemented in the simulation code (Thermoflex®) to reduce the power output. In the latter case, the impact of ambient temperature (Tamb) on the minimum cycle temperature (Tmin) was evaluated. The ultimate goal is to predict the thermal efficiency (ηth) and its decrease due to partial load operation and warm climate, without thermal recovery from the air separation unit (ASU). With the most efficient partial load strategy, ηth decreased from 50.4% at full load to 40.3% at about 30% load, at nominal Tmin. The penalty caused by the increase in Tmin due to hot weather, up to Tamb = 30 °C, was significant at loads above 60%, but limited to 0.5 percentage points (pp)
Publisher correction: Spatio-temporal variability of processes across Antarctic ice-bed-ocean interfaces (vol 9, 2289, 2018)
No full textThe original version of this Article contained an error in the spelling of the author Florence Colleoni, which was incorrectly given as Florence Colloni. This has been corrected in both the PDF and HTML versions of the Article
Antiinflammatory action of endocannabinoid palmitoylethanolamide and the synthetic cannabinoid nabilone in a model of acute inflammation in the rat
No full textInvestigation of 18F-FDG PET in the selection of patients with breast cancer as candidates for sentinel node biopsy after neoadjuvant therapy
No full textPurpose The main objective of this study was to determine the role of [ 18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) in the selection of patients with breast cancer as candidates for sentinel node biopsy (SNB) after neoadjuvant therapy. Methods Forty-four patients with primary breast cancer clinically classified as cT2, cT3 or cT4 a-c cN0-N2 or cN3 M0 and with a baseline FDG PET scan positive both in the site of primary tumour and axillary lymph nodes underwent neoadjuvant therapy and then a second FDG PET scan. In the case of axillary FDG PET uptake, patients underwent axillary lymph node dissection (ALND). If the second FDG PET scan was negative for axillary involvement, SNB was performed in order to evaluate axillary lymph node status. Only in the case of SN positivity did total ALND follow. Results Specificity and positive predictive value of FDG PET for detection of axillary lymph node metastases after neoadjuvant therapy were as high as 83% (95% confidence interval: 51-97%) and 85% (95% confidence interval: 54-97%), respectively, whereas sensitivity, negative predictive value and diagnostic accuracy were inadequate for a correct staging (34, 32 and 48%, respectively). Conclusion The poor sensitivity of FDG PET in detecting axillary lymph node metastases makes SNB mandatory in cases of a negative scan. The relatively high positive predictive value seems to suggest a role of FDG PET in selecting patients who, after neoadjuvant therapy, are candidates for ALND, avoiding SNB. However, this issue requires confirmation in a larger series of patients. © Springer-Verlag 2010
Isolation, growth and differentiation of equine mesenchymal stem cells : effect of donor, source, amount of tissue and supplementation with basic fibroblast growth factor
No full textMesenchymal stem cells (MSC) are increasingly used as therapeutical aid for the orthopaedic injuries in the horse. MSC populate different tissues but the most commonly used for clinical purposes are isolated from bone marrow or adipose tissue. The first objective of this study was to investigate if the donor animal, the tissue of origin and the technique of isolation could influence the number of MSC available for transplantation after a short-term expansion. The second aim was to devise a culture system capable of increasing MSC lifespan and we tested the effect of basic fibroblast growth factor (bFGF). Results indicate that MSC can be efficiently isolated from both sources and supplementation of bFGF enhances proliferation rate maintaining differentiation potential. In addition, this study shows that collection, expansion and storage of frozen MSC can be performed for later therapeutic use
New Methods for Selecting Stallion Spermatozoa for Assisted Reproduction
No full textImproved sperm selection techniques are needed to increase the efficiency of equine-assisted reproduction. Single layer centrifugation (SLC) of spermatozoa has been shown to improve the quality of stallion sperm samples. In this study, the functionality of selected stallion spermatozoa was tested by intracytoplasmic sperm injection of equine oocytes after selection by SLC through Androcoll-E or by discontinuous density gradient centrifugation (DGC) through Redigrad and Tyrodes medium with added albumin, lactate, and pyruvate. The mean cleavage rates of the injected oocytes from SLC- and DGC-selected spermatozoa were 67% and 66%, respectively, whereas the proportion of blastocysts developing from cleaved oocytes was 28% and 22%, respectively (P andgt; .05, not significant). An incidental finding was that there was a tendency for SLC-selected spermatozoa to have a higher percentage of spermatozoa with normal morphology than DGC (70% +/- 22% vs. 58% +/- 38%) and for more blastocysts to be obtained from subfertile ejaculates (21 [19.6%] vs. 15 [14.4%], respectively). In further experiments, stallion spermatozoa bound to hyaluronan, although binding may depend on the semen extender and sperm treatment as well as incubation time. In conclusion, SLC-selected stallion spermatozoa function normally when injected into oocytes. SLC may potentially be better than DGC at selecting spermatozoa from subfertile ejaculates, but this effect needs rigorous investigation with a much larger sample size. Use of the hyaluronan-binding assay for assessing the potential fertility of stallion spermatozoa may be useful but requires further evaluation.
Genistein, a natural phytoestrogen from soy, relieves neuropathic pain following chronic constriction sciatic nerve injury in mice : anti-inflammatory and antioxidant activity
No full textThere is great interest in soy isoflavones as alternatives to endogenous estrogens not only in hormonal pathologies, but also in inflammatory, neurodegenerative diseases and pain. We investigated the effect of the isoflavone genistein on neuropathic pain. Genistein binds estrogen receptors (ER) with higher affinity for the ERbeta particularly expressed in neuronal and immune cells. Neuropathy was induced in mice by means of chronic sciatic nerve constriction, and the subcutaneous administration of genistein from the third day after the lesion reversed pain hypersensitivity in a time- and dose-dependent manner. This effect may have been due to the activation of classical nuclear receptor and/or anti-oxidant, anti-inflammatory and immunomodulating properties of genistein. The fact that a specific ERbeta antagonist prevented both its anti-allodynic and anti-hyperalgesic action, whereas a specific ERalpha antagonist was ineffective and a non-selective ER antagonist only reversed the anti-allodynic effect, suggests the involvement of ERbeta. Antioxidant effects are also involved as the anti-nociceptive dose reversed the increase in reactive oxygen species and malondialdehyde in injured paw tissues, and increased the activity of anti-oxidant enzymes. The phytoestrogen had immunomodulatory and anti-inflammatory activities as it reduced peripheral and central nuclear factor-small ka, Cyrillicappa B, nitric oxide system and pro-inflammatory cytokine over-activation. Taken together, our results suggest that genistein could ameliorate painful neuropathy by multiple mechanisms
The soy isoflavone genistein reverses oxidative and inflammatory state, neuropathic pain, neurotrophic and vasculature deficits in diabetes mouse model
No full textTreatment of diabetes complications remains a substantial challenge. The aim of this study was to explore the ability of the soy isoflavone genistein in attenuating the signs that follow diabetes onset: nociceptive hypersensitivity, oxidative and inflammatory state, nerve growth factor (NGF) decrease and vascular dysfunctions. Genistein (3 and 6 mg/kg) was administered to C57BL/6J streptozotocin diabetic mice from the 2nd till the 5th week after disease induction. The hind paw withdrawal threshold to mechanical stimulation (tactile allodynia) was evaluated by a von Frey filament. The oxidative stress was assessed measuring: reactive oxygen species by fluorimetric analysis, both the lipoperoxide content, as malondialdehyde, the antioxidant enzymatic activities spectrophotometrically and the glutathione content spectrofluorimetrically. Proinflammatory cytokines and NGF were measured in the sciatic nerve by enzyme-linked immunosorbent assay. Aortic inducible (iNOS) and endothelial nitric oxide synthase (eNOS) protein content was measured by western immunoblotting. Genistein relieved diabetic peripheral painful neuropathy, reverted the proinflammatory cytokine and reactive oxygen species overproduction, and restored the NGF content in diabetic sciatic nerve. Furthermore it restored the GSH content and the GSH and GSSG ratio, improved the antioxidant enzymes activities, decreased reactive oxygen species and lipoperoxide level in the brain and liver. Finally it restored the iNOS and eNOS content and the superoxide dismutase activity in thoracic aorta. Hyperglycaemia and weight decrease were not affected. Genistein is able to reverse a diabetes established condition of allodynia, oxidative stress and inflammation, ameliorates NGF content and the vascular dysfunction, thus suggesting its possible therapeutic use for diabetes complications
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