107 research outputs found

    Applicazione al parco naturale della valle del Ticino di un modello per l'analisi del comportamento degli utenti : la calibrazione del modello

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    Working Paper; n. 5- Indice #7- Descrizione del parco #9- Descrizione delle informazioni necessarie #15- Esposizione dei risultati #2

    Nested Dynamics of Metropolitan Processes and Policies: Turin

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    BACKGROUND PAPERS FOR THE METROPOLITAN STUDY: 3 -- The project "Nested Dynamics of Metropolitan Processes and Policies" was initiated by the Regional and urban Development Group at IIASA in 1983 and work on this collaborative study started the same year. This Series of contributions represents "entry tickets" to the Project, i.e., initial statements by authors from individual metropolitan regions that are participating in the Project's network. The aim of these papers is threefold. First, to provide some background information describing the processes of change within four principal subsystems: population, housing, economy, and transportation. Second, to identify major trends and crucial policy issues which are to constitute a focus for the subsequent analytical and modeling work. Third, to facilitate comparative studies of development paths among these regions and the dynamic interdependencies between the above subsystems. The background information contained in this paper pertains to the Turin metropolitan region

    Applicazione al parco naturale della valle del Ticino di un modello per l'analisi del comportamento degli utenti : l'uso del modello

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    Working Paper; n. 6- Indice #7- Uso del modello con i valori ottenuti nella calibrazione ed in assenza di interventi #10- Bibliografia #2

    Mechanical Properties of Animal Tendons: A Review and Comparative Study for the Identification of the Most Suitable Human Tendon Surrogates

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    The mechanical response of a tendon to load is strictly related to its complex and highly organized hierarchical structure, which ranges from the nano-to macroscale. In a broader context, the mechanical properties of tendons during tensile tests are affected by several distinct factors, due in part to tendon nature (anatomical site, age, training, injury, etc.) but also depending on the experimental setup and settings. This work aimed to present a systematic review of the mechanical properties of tendons reported in the scientific literature by considering different anatomical regions in humans and several animal species (horse, cow, swine, sheep, rabbit, dog, rat, mouse, and foal). This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method. The literature research was conducted via Google Scholar, PubMed, PicoPolito (Politecnico di Torino’s online catalogue), and Science Direct. Sixty studies were selected and analyzed. The structural and mechanical properties described in different animal species were reported and summarized in tables. Only the results from studies reporting the strain rate parameter were considered for the comparison with human tendons, as they were deemed more reliable. Our findings showed similarities between animal and human tendons that should be considered in biomechanical evaluation. An additional analysis of the effects of different strain rates showed the influence of this parameter

    Mechanical properties of animal ligaments: a review and comparative study for the identification of the most suitable human ligament surrogates

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    : The interest in the properties of animal soft tissues is often related to the desire to find an animal model to replace human counterparts due to the unsteady availability of human tissues for experimental purposes. Once the most appropriate animal model is identified, it is possible to carry out ex-vivo and in-vivo studies for the repair of ligamentous tissues and performance testing of replacement and support healing devices. This work aims to present a systematic review of the mechanical properties of ligaments reported in the scientific literature by considering different anatomical regions in humans and several animal species. This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method. Moreover, considering the lack of a standard protocol for preconditioning of tissues, this aspect is also addressed. Ninety-six studies were selected for the systematic review and analysed. The mechanical properties of different animal species are reported and summarised in tables. Only results from studies reporting the strain rate parameter were considered for comparison with human ligaments, as they were deemed more reliable. Elastic modulus, ultimate tensile stress, and ultimate strain properties are graphically reported identifying the range of values for each animal species and to facilitate comparison between values reported in the scientific literature in animal and human ligaments. Useful similarities between the mechanical properties of swine, cow, and rat and human ligaments have been found

    Does contrast echocardiography induce increases in markers of myocardial necrosis, inflammation and oxidative stress suggesting myocardial injury?

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    BACKGROUND: Contrast echocardiography is a precise tool for the non-invasive assessment of myocardial function and perfusion. Side effects of contrast echocardiography resulting from contrast-agent induced myocardial micro-lesions have been found in animals. The goal of this study is to measure markers of myocardial necrosis, inflammation and oxidative stress in humans to evaluate potential side-effects of contrast echocardiography. METHODS: 20 patients who underwent contrast echocardiography with Optison as the contrast medium were investigated. To evaluate myocardial micro-necrosis, inflammation and oxidative stress, cardiac troponin I (cTnI), tumor necrosis factor-Ξ± (TNF-Ξ±), interleukin (IL)-6, -8 and thiobarbituric acid reactive substances (TBARS) were measured at baseline and at 2, 4, 8 and 24 hours after contrast echocardiography. RESULTS: At baseline, 50% of the patients had cTnI and TBARS values outside the reference range. TNF-Ξ±, IL-6, IL-8 levels were within the reference range. Patients with cTnI above the RR clustered to significantly higher levels of TNF-Ξ± and IL-6. After contrast echocardiography, no statistically significant increase of cTnI, cytokines and TBARS was found. However, for nearly 50% of the patients, the intra-individual cTnI kinetics crossed the critical difference (threefold of methodical variation) which indicates a marker increase. This was neither predicted by the baseline levels of the cytokines nor the markers of oxidative stress. CONCLUSION: There are no clinically relevant increases in serum markers for micro-necrosis, inflammation and oxidative stress in humans after contrast echocardiography. Future studies have to address whether cTnI increase in some patients represent a subset with increased risk for side effects after contrast echocardiography

    Local Oxidative and Nitrosative Stress Increases in the Microcirculation during Leukocytes-Endothelial Cell Interactions

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    Leukocyte-endothelial cell interactions and leukocyte activation are important factors for vascular diseases including nephropathy, retinopathy and angiopathy. In addition, endothelial cell dysfunction is reported in vascular disease condition. Endothelial dysfunction is characterized by increased superoxide (O2β€’βˆ’) production from endothelium and reduction in NO bioavailability. Experimental studies have suggested a possible role for leukocyte-endothelial cell interaction in the vessel NO and peroxynitrite levels and their role in vascular disorders in the arterial side of microcirculation. However, anti-adhesion therapies for preventing leukocyte-endothelial cell interaction related vascular disorders showed limited success. The endothelial dysfunction related changes in vessel NO and peroxynitrite levels, leukocyte-endothelial cell interaction and leukocyte activation are not completely understood in vascular disorders. The objective of this study was to investigate the role of endothelial dysfunction extent, leukocyte-endothelial interaction, leukocyte activation and superoxide dismutase therapy on the transport and interactions of NO, O2β€’βˆ’ and peroxynitrite in the microcirculation. We developed a biotransport model of NO, O2β€’βˆ’ and peroxynitrite in the arteriolar microcirculation and incorporated leukocytes-endothelial cell interactions. The concentration profiles of NO, O2β€’βˆ’ and peroxynitrite within blood vessel and leukocytes are presented at multiple levels of endothelial oxidative stress with leukocyte activation and increased superoxide dismutase accounted for in certain cases. The results showed that the maximum concentrations of NO decreased ∼0.6 fold, O2β€’βˆ’ increased ∼27 fold and peroxynitrite increased ∼30 fold in the endothelial and smooth muscle region in severe oxidative stress condition as compared to that of normal physiologic conditions. The results show that the onset of endothelial oxidative stress can cause an increase in O2β€’βˆ’ and peroxynitrite concentration in the lumen. The increased O2β€’βˆ’ and peroxynitrite can cause leukocytes priming through peroxynitrite and leukocytes activation through secondary stimuli of O2β€’βˆ’ in bloodstream without endothelial interaction. This finding supports that leukocyte rolling/adhesion and activation are independent events

    A theory and methodology to quantify knowledge

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    This article proposes quantitative answers to meta-scientific questions including 'how much knowledge is attained by a research field?', 'how rapidly is a field making progress?', 'what is the expected reproducibility of a result?', 'how much knowledge is lost from scientific bias and misconduct?', 'what do we mean by soft science?', and 'what demarcates a pseudoscience?'. Knowledge is suggested to be a system-specific property measured by K, a quantity determined by how much of the information contained in an explanandum is compressed by an explanans, which is composed of an information 'input' and a 'theory/methodology' conditioning factor. This approach is justified on three grounds: (i) K is derived from postulating that information is finite and knowledge is information compression; (ii) K is compatible and convertible to ordinary measures of effect size and algorithmic complexity; (iii) K is physically interpretable as a measure of entropic efficiency. Moreover, the K function has useful properties that support its potential as a measure of knowledge. Examples given to illustrate the possible uses of K include: the knowledge value of proving Fermat's last theorem; the accuracy of measurements of the mass of the electron; the half life of predictions of solar eclipses; the usefulness of evolutionary models of reproductive skew; the significance of gender differences in personality; the sources of irreproducibility in psychology; the impact of scientific misconduct and questionable research practices; the knowledge value of astrology. Furthermore, measures derived from K may complement ordinary meta-analysis and may give rise to a universal classification of sciences and pseudosciences. Simple and memorable mathematical formulae that summarize the theory's key results may find practical uses in meta-research, philosophy and research policy
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