5,564 research outputs found

    Renormalization flow for unrooted forests on a triangular lattice

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    We compute in small temperature expansion the two-loop renormalization constants and the three-loop coefficient of the beta-function, that is the first non-universal term, for the sigma-model with O(N) invariance on the triangular lattice at N=-1. The partition function of the corresponding Grassmann theory is, for negative temperature, the generating function of unrooted forests on such a lattice, where the temperature acts as a chemical potential for the number of trees in the forest. To evaluate Feynman diagrams we extend the coordinate space method to the triangular lattice.Comment: 26 pages, 4 figure

    How to chose innovation policies to foster SMEs growth. A region - industry - firm type approach

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    This paper aimed at defining a common methodological framework for the evaluation and decision regarding innovation policy instruments, suitable for an international comparative approach. It may be useful in empirical analysis and operative projects. In particular, the originality of the methodology are the interdisciplinary approach, considering all three main factors affecting innovation systems, especially when thinking to SMEs: the territorial, the technological and the entrepreneurship dimension. In addition, the methodology has adopted a demand driven approach, based on the precise identification of the needs of services, by analysing them according to different dimensions: industries/technologies, firms and regions. Thus, the study has adopted a strategic perspective and it indicates that the identification of the strengths, weaknesses, opportunities and threats is facilitating the identification of the actual needs and demand of technology transfer services in a given region. The methodology is also characterized for having analysed a wide variety of the instruments, which can be used in innovation policies ranging from a top-down, governmental approach to a bottom-up and market approach. This model allows to support decision makers in measuring in a more rigorous and quantitative way the complementarities and the trade-offs of these innovation policy instruments, while aiming to respond to various and interdependent needs, which may have a different priority in various industries, firms and regions. This is clearly also an effective approach to investigate on regional attractiveness factors and it is a new method of evaluation when applying the model reversely, as well as it is useful to identify most suitable initiatives to apply to enhance the competitiveness of a territory.SMEs, Innovation Policies, Technology Trasfer, Regional Developement

    A systematic review of infected descending thoracic aortic grafts and endografts

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    Objective: The objective of this study was to collect and critically analyze the current evidence on the modalities and results of treatment of descending thoracic aortic surgical graft (SG) and endograft (EG) infection, which represents a rare but dramatic complication after both surgical and endovascular aortic repair. Methods: A comprehensive electronic health database search (PubMed/MEDLINE, Scopus, Google Scholar, and the Cochrane Library) identified all articles that were published up to October 2017 reporting on thoracic aortic SG or EG infection. Observational studies, multicenter reports, single-center series and case reports, case-control studies, and guidelines were considered eligible if reporting specific results of treatment of descending thoracic aortic SG or EG infection. Comparisons of patients presenting with SG or EG infection and between invasive and conservative treatment were performed. Odds ratio (OR) meta-analyses were run when comparative data were available. Results: Forty-three studies reporting on 233 patients with infected SG (49) or EG (184) were included. Four were multicenter studies including 107 patients, all with EG infection, associated with a fistula in 91% of cases, with a reported overall survival at 2 years of 16% to 39%. The remaining 39 single-center studies included 49 patients with SG infection and 77 with EG infection. Association with aortoesophageal fistula was significantly more common with EG (60% vs 31%; P = .01). In addition, time interval from index procedure to infection was significantly shorter with EG (17 +/- 21 months vs 32 +/- 61 months; P = .03). Meta-analysis showed a trend of increased 1-year mortality in patients with SG infection compared with EG infection (pooled OR, 3.6; 95% confidence interval, 0.9-14.7; P = .073). Surgical management with infected graft explantation was associated with a trend toward lower 1-year mortality compared with graft preservation (pooled OR, 0.3; 95% confidence interval, 0.1-1.0; P = .056). Conclusions: Thoracic aortic EG infection is likely to occur more frequently in association with aortoesophageal fistulas and in a shorter time compared with SG infection. Survival is poor in both groups, especially in patients with SG infection. Surgical treatment with graft explantation seems to be the preferable choice in fit patients

    Tissue-engineered grafts from human decellularized extracellular matrices: A systematic review and future perspectives

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    Tissue engineering and regenerative medicine involve many different artificial and biologic materials, frequently integrated in composite scaffolds, which can be repopulated with various cell types. One of the most promising scaffolds is decellularized allogeneic extracellular matrix (ECM) then recellularized by autologous or stem cells, in order to develop fully personalized clinical approaches. Decellularization protocols have to efficiently remove immunogenic cellular materials, maintaining the nonimmunogenic ECM, which is endowed with specific inductive/differentiating actions due to its architecture and bioactive factors. In the present paper, we review the available literature about the development of grafts from decellularized human tissues/organs. Human tissues may be obtained not only from surgery but also from cadavers, suggesting possible development of Human Tissue BioBanks from body donation programs. Many human tissues/organs have been decellularized for tissue engineering purposes, such as cartilage, bone, skeletal muscle, tendons, adipose tissue, heart, vessels, lung, dental pulp, intestine, liver, pancreas, kidney, gonads, uterus, childbirth products, cornea, and peripheral nerves. In vitro recellularizations have been reported with various cell types and procedures (seeding, injection, and perfusion). Conversely, studies about in vivo behaviour are poorly represented. Actually, the future challenge will be the development of human grafts to be implanted fully restored in all their structural/functional aspects

    How to chose innovation policies to foster SMEs growth. A region - industry - firm type approach

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    This paper aimed at defining a common methodological framework for the evaluation and decision regarding innovation policy instruments, suitable for an international comparative approach. It may be useful in empirical analysis and operative projects. In particular, the originality of the methodology are the interdisciplinary approach, considering all three main factors affecting innovation systems, especially when thinking to SMEs: the territorial, the technological and the entrepreneurship dimension. In addition, the methodology has adopted a demand driven approach, based on the precise identification of the needs of services, by analysing them according to different dimensions: industries/technologies, firms and regions. Thus, the study has adopted a strategic perspective and it indicates that the identification of the strengths, weaknesses, opportunities and threats is facilitating the identification of the actual needs and demand of technology transfer services in a given region. The methodology is also characterized for having analysed a wide variety of the instruments, which can be used in innovation policies ranging from a top-down, governmental approach to a bottom-up and market approach. This model allows to support decision makers in measuring in a more rigorous and quantitative way the complementarities and the trade-offs of these innovation policy instruments, while aiming to respond to various and interdependent needs, which may have a different priority in various industries, firms and regions. This is clearly also an effective approach to investigate on regional attractiveness factors and it is a new method of evaluation when applying the model reversely, as well as it is useful to identify most suitable initiatives to apply to enhance the competitiveness of a territory

    Outdoor work and solar radiation exposure: Evaluation method for epidemiological studies.

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    Background: The health risk related to an excessive exposure to solar radiation (SR) is well known. The Sun represents the main exposure source for all the frequency bands of optical radiation, that is the part of the electromagnetic spectrum ranging between 100 nm and 1 mm, including infrared (IR), ultraviolet (UV) and visible radiation. According to recent studies, outdoor workers have a relevant exposure to SR but few studies available in scientific literature have attempted to retrace a detailed history of individual exposure. Material and Methods: We propose a new method for the evaluation of SR cumulative exposure both during work and leisure time, integrating subjective and objective data. The former is collected by means of an interviewer administrated questionnaire. The latter is available through the Internet databases for many geographical regions and through individual exposure measurements. The data is integrated into a mathematical algorithm, in order to obtain an esteem of the individual total amount of SR the subjects have been exposed to during their lives. Results: The questionnaire has been tested for 58 voluntary subjects. Environmental exposure data through online databases has been collected for 3 different places in Italy in 2012. Individual exposure by electronic UV dosimeter has been measured in 6 fishermen. A mathematical algorithm integrating subjective and objective data has been elaborated. Conclusions: The method proposed may be used in epidemiological studies to evaluate specific correlations with biological effects of SR and to weigh the role of the personal and environmental factors that may increase or reduce SR exposure

    Research progress on aerobiology in the last 30 years. A focus on methodology and occupational health

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    Aerobiology, as a scientific discipline, developed during the last century and has been applied to different types of organisms and scenarios. In the context of the Integrated Evaluation of Indoor Particulate Exposure (VIEPI) project, we conducted a bibliometric study of the scientific literature on aerobiology from the last three decades, establishing the recent advances and the critical issues regarding the application of aerobiological methods to occupational settings. The data were collected from Scopus,Web of Science and PubMed. We explored the distribution of the articles in different years and research areas and realized a bibliometric analysis using the CiteSpace software. The results indicated that the number of publications is increasing. The studies related to environmental sciences were the most represented, while the number of occupational studies was more limited. The most common keywords were related to pollen, fungal spores and their relation with phenology, climate change and human health. This article shows that aerobiology is not restricted to the study of pollen and spores, extending the discipline and the application of aerobiological methods to occupational settings, currently under-explored

    Impact of climate change on occupational exposure to solar radiation

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    Occupational exposure to solar radiation may induce both acute and long-term effects on skin and eyes. Personal exposure is very difficult to assess accurately, as it depends on environmental, organisational and individual factors. The ongoing climate change interacting with stratospheric ozone dynamics may affect occupational exposure to solar radiation. In addition, tropospheric levels of environmental pollutants interacting with solar radiation may be altered by climate dynamics, so introducing another variable affecting the overall exposure to solar radiation. Given the uncertainties regarding the direction of changes in exposure to solar radiation due to climate change, compliance of outdoor workers with protective measures and a proper health surveillance are crucial. At the same time, education and training, along with the promotion of healthier lifestyles, are of paramount importance

    A fully automated micro‑CT deep learning approach for precision preclinical investigation of lung fibrosis progression and response to therapy

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    : Micro-computed tomography (µCT)-based imaging plays a key role in monitoring disease progression and response to candidate drugs in various animal models of human disease, but manual image processing is still highly time-consuming and prone to operator bias. Focusing on an established mouse model of bleomycin (BLM)-induced lung fibrosis we document, here, the ability of a fully automated deep-learning (DL)-based model to improve and speed-up lung segmentation and the precise measurement of morphological and functional biomarkers in both the whole lung and in individual lobes. µCT-DL whose results were overall highly consistent with those of more conventional, especially histological, analyses, allowed to cut down by approximately 45-fold the time required to analyze the entire dataset and to longitudinally follow fibrosis evolution and response to the human-use-approved drug Nintedanib, using both inspiratory and expiratory μCT. Particularly significant advantages of this µCT-DL approach, are: (i) its reduced experimental variability, due to the fact that each animal acts as its own control and the measured, operator bias-free biomarkers can be quantitatively compared across experiments; (ii) its ability to monitor longitudinally the spatial distribution of fibrotic lesions, thus eliminating potential confounding effects associated with the more severe fibrosis observed in the apical region of the left lung and the compensatory effects taking place in the right lung; (iii) the animal sparing afforded by its non-invasive nature and high reliability; and (iv) the fact that it can be integrated into different drug discovery pipelines with a substantial increase in both the speed and robustness of the evaluation of new candidate drugs. The µCT-DL approach thus lends itself as a powerful new tool for the precision preclinical monitoring of BLM-induced lung fibrosis and other disease models as well. Its ease of operation and use of standard imaging instrumentation make it easily transferable to other laboratories and to other experimental settings, including clinical diagnostic applications

    Who should be screened for secondary causes of hypertension?

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    The case of a 34-year-old patient with uncontrolled hypertension is described in this article, together with the diagnostic path followed in order to make the diagnosis, that finally reveals an arteriovenous fistula due to an old kidney biopsy. Uncontrolled or resistant hypertension may be caused by unrecognized secondary hypertension: we revise the clinical and laboratory criteria for selecting hypertensive patients in whom to look for secondary hypertension through the most appropriate diagnostic work up. A synthesis of the main causes of secondary hypertension is also provided in the discussion
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