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21.
Mario Mariani Ugo Ravasio Armando Buttafava Antonio Faucitano 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2007,265(1):245-250
The effect of gamma irradiation in air is investigated in two thermoplastic polyesters (PET and PEN), in order to evaluate the influence of aromatic density and the role of oxygen on radiation resistance. EPR measurements were carried out to detect radical stability against oxygen permeation and to provide radical characterization. Viscometric data reveal a different behaviour between films and thick samples. Positron annihilation spectra show a decrease of ortho-positronium intensity, which is more marked in film samples. ortho-positronium lifetime does not depend on the radiation dose. 相似文献
22.
Visual processing was investigated in judgments of relative line position. Stimulus continua were generated by bisecting a straight line and displacing the segments. Experiment 1 measured discrimination of pairs of longitudinally displaced segments at equal steps along the continuum. At long (2 s) durations discrimination fell smoothly, but at short (100 ms) durations it was sharp-peaked. In Experiment 2 the short-duration stimuli were labeled with subsets of the labels no gap, just a gap, and more than just a gap. Theoretical discrimination performances were computed and the one based on no gap and just a gap closely fitted observed performance. Experiments 3 and 4 were similar to 1 and 2, with lateral replacing longitudinal displacement. Similar "categorical" performance was obtained. It was concluded that there are discrete mechanisms for early detection of relative line position and that 2 labels can be used to characterize performance in each direction. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
23.
This paper discuss several quantitative issues that arise in the analysis of health risks, beginning with principles such as de minimis and zero-risk. The paper also provides a probabilistic definition of risk in terms of hazard, context, consequence, magnitude, and uncertainty. The example relies on this definition to investigate, through sensitivity analysis, the effect that uncertainty has on the results obtained. The results, from a case study based on waterborne total arsenic, show that the choice of dose—response functions causes more uncertainty than any other component of risk analysis. Chemical carcinogenesis provides the basis for discussing inability to know as well as uncertainty. The conclusion is that risk analysis keeps uncertainty and inability to know separate; through this function, it provides a much needed method to present information to decision makers and the public. 相似文献
24.
Mario Bunge 《Technology in Society》1998,20(4):377-383
The thesis of this paper is that ethics and action theory are the two philosophical branches of technology. The reason is that they, just like mechanical engineering and management science, are concerned with human action. But of course there are differences between the philosophical technologies and the others, among them their degree of generality. An example from ethics and another from praxiology are discussed, to show that these disciplines can be just as exact and relevant to real contemporary life as electrical engineering and law. Finally, some consequences for the classification of technologies and for the design of academic curricula are drawn. 相似文献
25.
26.
José M. Cecilia José M. García Ginés D. Guerrero Miguel A. Martínez-del-Amor Mario J. Pérez-Jiménez Manuel Ujaldón 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2012,16(2):231-246
Membrane Computing is a discipline aiming to abstract formal computing models, called membrane systems or P systems, from the structure and functioning of the living cells as well as from the cooperation of cells in tissues, organs, and
other higher order structures. This framework provides polynomial time solutions to NP-complete problems by trading space
for time, and whose efficient simulation poses challenges in three different aspects: an intrinsic massively parallelism of
P systems, an exponential computational workspace, and a non-intensive floating point nature. In this paper, we analyze the
simulation of a family of recognizer P systems with active membranes that solves the Satisfiability problem in linear time
on different instances of Graphics Processing Units (GPUs). For an efficient handling of the exponential workspace created
by the P systems computation, we enable different data policies to increase memory bandwidth and exploit data locality through
tiling and dynamic queues. Parallelism inherent to the target P system is also managed to demonstrate that GPUs offer a valid
alternative for high-performance computing at a considerably lower cost. Furthermore, scalability is demonstrated on the way
to the largest problem size we were able to run, and considering the new hardware generation from Nvidia, Fermi, for a total
speed-up exceeding four orders of magnitude when running our simulations on the Tesla S2050 server. 相似文献
27.
Roberto Lande Immacolata Pietraforte Anna Mennella Raffaella Palazzo Francesca Romana Spinelli Konstantinos Giannakakis Francesca Spadaro Mario Falchi Valeria Riccieri Katia Stefanantoni Curdin Conrad Cristiano Alessandri Fabrizio Conti Loredana Frasca 《International journal of molecular sciences》2021,22(4)
LL37 acts as T-cell/B-cell autoantigen in Systemic lupus erythematosus (SLE) and psoriatic disease. Moreover, when bound to “self” nucleic acids, LL37 acts as “danger signal,” leading to type I interferon (IFN-I)/pro-inflammatory factors production. T-cell epitopes derived from citrullinated-LL37 act as better antigens than unmodified LL37 epitopes in SLE, at least in selected HLA-backgrounds, included the SLE-associated HLA-DRB1*1501/HLA-DRB5*0101 backgrounds. Remarkably, while “fully-citrullinated” LL37 acts as better T-cell-stimulator, it loses DNA-binding ability and the associated “adjuvant-like” properties. Since LL37 undergoes a further irreversible post-translational modification, carbamylation and antibodies to carbamylated self-proteins other than LL37 are present in SLE, here we addressed the involvement of carbamylated-LL37 in autoimmunity and inflammation in SLE. We detected carbamylated-LL37 in SLE-affected tissues. Most importantly, carbamylated-LL37-specific antibodies and CD4 T-cells circulate in SLE and both correlate with disease activity. In contrast to “fully citrullinated-LL37,” “fully carbamylated-LL37” maintains both innate and adaptive immune-cells’ stimulatory abilities: in complex with DNA, carbamylated-LL37 stimulates plasmacytoid dendritic cell IFN-α production and B-cell maturation into plasma cells. Thus, we report a further example of how different post-translational modifications of a self-antigen exert complementary effects that sustain autoimmunity and inflammation, respectively. These data also show that T/B-cell responses to carbamylated-LL37 represent novel SLE disease biomarkers. 相似文献
28.
Neuroprotective Effects of Testosterone in the Hypothalamus of an Animal Model of Metabolic Syndrome
Erica Sarchielli Paolo Comeglio Sandra Filippi Ilaria Cellai Giulia Guarnieri Alessandra Marzoppi Sarah Cipriani Linda Vignozzi Annamaria Morelli Mario Maggi 《International journal of molecular sciences》2021,22(4)
Metabolic syndrome (MetS) is known to be associated to inflammation and alteration in the hypothalamus, a brain region implicated in the control of several physiological functions, including energy homeostasis and reproduction. Previous studies demonstrated the beneficial effects of testosterone treatment (TTh) in counteracting some MetS symptoms in both animal models and clinical studies. This study investigated the effect of TTh (30 mg/kg/week for 12 weeks) on the hypothalamus in a high-fat diet (HFD)-induced animal model of MetS, utilizing quantitative RT-PCR and immunohistochemical analyses. The animal model recapitulates the human MetS features, including low testosterone/gonadotropin plasma levels. TTh significantly improved MetS-induced hypertension, visceral adipose tissue accumulation, and glucose homeostasis derangements. Within hypothalamus, TTh significantly counteracted HFD-induced inflammation, as detected in terms of expression of inflammatory markers and microglial activation. Moreover, TTh remarkably reverted the HFD-associated alterations in the expression of important regulators of energy status and reproduction, such as the melanocortin and the GnRH-controlling network. Our results suggest that TTh may exert neuroprotective effects on the HFD-related hypothalamic alterations, with positive outcomes on the circuits implicated in the control of energy metabolism and reproductive tasks, thus supporting a possible role of TTh in the clinical management of MetS. 相似文献
29.
Margaret Ottaviano Emilio Francesco Giunta Marianna Tortora Marcello Curvietto Laura Attademo Davide Bosso Cinzia Cardalesi Mario Rosanova Pietro De Placido Erica Pietroluongo Vittorio Riccio Brigitta Mucci Sara Parola Maria Grazia Vitale Giovannella Palmieri Bruno Daniele Ester Simeone 《International journal of molecular sciences》2021,22(7)
As widely acknowledged, 40–50% of all melanoma patients harbour an activating BRAF mutation (mostly BRAF V600E). The identification of the RAS–RAF–MEK–ERK (MAP kinase) signalling pathway and its targeting has represented a valuable milestone for the advanced and, more recently, for the completely resected stage III and IV melanoma therapy management. However, despite progress in BRAF-mutant melanoma treatment, the two different approaches approved so far for metastatic disease, immunotherapy and BRAF+MEK inhibitors, allow a 5-year survival of no more than 60%, and most patients relapse during treatment due to acquired mechanisms of resistance. Deep insight into BRAF gene biology is fundamental to describe the acquired resistance mechanisms (primary and secondary) and to understand the molecular pathways that are now being investigated in preclinical and clinical studies with the aim of improving outcomes in BRAF-mutant patients. 相似文献
30.
Luis O. Soto-Rojas B. Berenice Campa-Crdoba Charles R. Harrington Andrs Salas-Casas Mario Hernandes-Alejandro Ignacio Villanueva-Fierro Marely Bravo-Muoz Linda Garcs-Ramírez Fidel De La Cruz-Lpez Miguel ngel Ontiveros-Torres Goar Gevorkian Mar Pacheco-Herrero Jos Luna-Muoz 《International journal of molecular sciences》2021,22(7)
Alzheimer’s disease (AD) is a neurodegenerative disease, characterized histopathologically by intra-neuronal tau-related lesions and by the accumulation of amyloid β-peptide (Aβ) in the brain parenchyma and around cerebral blood vessels. According to the vascular hypothesis of AD, an alteration in the neurovascular unit (NVU) could lead to Aβ vascular accumulation and promote neuronal dysfunction, accelerating neurodegeneration and dementia. To date, the effects of insoluble vascular Aβ deposits on the NVU and the blood–brain barrier (BBB) are unknown. In this study, we analyze different Aβ species and their association with the cells that make up the NVU. We evaluated post-mortem AD brain tissue. Multiple immunofluorescence assays were performed against different species of Aβ and the main elements that constitute the NVU. Our results showed that there are insoluble vascular deposits of both full-length and truncated Aβ species. Besides, insoluble aggregates are associated with a decrease in the phenotype of the cellular components that constitute the NVU and with BBB disruption. This approach could help identify new therapeutic targets against key molecules and receptors in the NVU that can prevent the accumulation of vascular fibrillar Aβ in AD. 相似文献