Creep, Relaxation and Viscosity Properties for Basic Fractional Models in Rheology

The purpose of this paper is twofold: from one side we provide a general survey to the viscoelastic models constructed via fractional calculus and from the other side we intend to analyze the basic fractional models as far as their creep, relaxation and viscosity properties are considered. The basic models are those that generalize via derivatives of fractional order the classical mechanical models characterized by two, three and four parameters, that we refer to as Kelvin-Voigt, Maxwell, Zener, anti-Zener and Burgers. For each fractional model we provide plots of the creep compliance, relaxation modulus and effective viscosity in non dimensional form in terms of a suitable time scale for different values of the order of fractional derivative. We also discuss the role of the order of fractional derivative in modifying the properties of the classical models.Comment: 41 pages, 8 figure

To what extent can dynamical models describe statistical features of turbulent flows?

Statistical features of "bursty" behaviour in charged and neutral fluid turbulence, are compared to statistics of intermittent events in a GOY shell model, and avalanches in different models of Self Organized Criticality (SOC). It is found that inter-burst times show a power law distribution for turbulent samples and for the shell model, a property which is shared only in a particular case of the running sandpile model. The breakdown of self-similarity generated by isolated events observed in the turbulent samples, is well reproduced by the shell model, while it is absent in all SOC models considered. On this base, we conclude that SOC models are not adequate to mimic fluid turbulence, while the GOY shell model constitutes a better candidate to describe the gross features of turbulence.Comment: 14 pages, 4 figures, in press on Europhys. Lett. (may 2002

Prevalence of Blood Types and Alloantibodies of the AB Blood Group System in Non-Pedigree Cats from Northern (Lombardy) and Southern (Sicily) Italy

The aims of this study were to determine the prevalence of A, B and AB blood types and alloantibodies in non-pedigree cats from two regions, one in Northern and one in Southern Italy (Lombardy and Sicily, respectively). A total of 448 samples (52.0% from Northern and 48.0% from Southern Italy) were blood typed. The prevalence of A, B and AB blood types in northern and southern cats were 91.0%, 5.2%, 3.8%, and 77.2%, 12.1% and 10.7%, respectively. The prevalence of type-A blood in southern cats was significantly lower (p = 0.0001) than in northern cats, while type-B and AB blood were significantly higher (p = 0.0085 and p = 0.0051, respectively) in Southern compared to Northern Italian cats. Alloantibodies against type-A blood were found in 94.1% of type-B cats, 11.2% of type-A cats had alloantibodies against type-B blood, while no type-AB cats had alloantibodies with no significant difference between the two Italian populations. Type-AB prevalence in non-pedigree cats in Southern Italy was the highest reported in Europe. Italian type-A cats had the lowest worldwide prevalence of alloantibodies against type-B blood. These results highlight the usefulness of regional studies to report different prevalences in feline blood types and reinforce the importance of blood typing cats before transfusions and mating

Ferulic acid metabolites attenuate lps-induced inflammatory response in enterocyte-like cells

Ferulic acid (FA) is a polyphenol pertaining to the class of hydroxycinnamic acids present in numerous foods of a plant origin. Its dietary consumption leads to the formation of several phase I and II metabolites in vivo, which represent the largest amount of ferulates in the circulation and in the intestine in comparison with FA itself. In this work, we evaluated their efficacy against the proinflam-matory effects induced by lipopolysaccharide (LPS) in intestinal Caco-2 cell monolayers, as well as the mechanisms underlying their protective action. LPS-induced overexpression of proinflammatory enzymes such as inducible nitric oxide synthase (iNOS) and the consequent hyperproduction of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) were limited by physiological relevant concentrations (1 µM) of FA, its derivatives isoferulic acid (IFA) and dihydroferulic acid (DHFA), and their glucuronidated and sulfated metabolites, which acted upstream by limiting the activation of MAPK p38 and ERK and of Akt kinase, thus decreasing the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) translocation into the nucleus. Furthermore, the compounds were found to promote the expression of Nrf2, which may have contributed to the downregulation of NF-kB activity. The overall data show that phase I/II metabolites retain the efficacy of their dietary free form in contrasting inflammatory response

Looking for the Elusive Imine Tautomer of Creatinine: Different States of Aggregation Studied by Quantum Chemistry and Molecular Spectroscopy

New spectroscopic experiments and state-of-the-art quantum-chemical computations of creatinine in different aggregation states unequivocally unveiled a significant tuning of tautomeric equilibrium by the environment: from the exclusive presence of the amine tautomer in the solid state and aqueous solution to a mixture of amine and imine tautomers in the gas phase. Quantum-chemical calculations predict the amine species as the most stable tautomer by about 30 kJ mol−1 in condensed phases. On the contrary, moving to the isolated forms, both Z and E imine isomers become more stable by about 7 kJ mol−1. Since the imine isomers and one amine tautomer are separated by significant energy barriers, all of them should be present in the gas phase. This prediction has indeed been confirmed by high-resolution rotational spectroscopy, which provides the first experimental characterization of the elusive imine tautomer. The interpretation of the complicated hyperfine structure of the rotational spectrum, originated by three 14N nuclei, makes it possible to use the spectral signatures as a sort of fingerprint for each individual tautomer in the complex sample

Gender influence on professional satisfaction and gender issue perception among young oncologists. A survey of the Young Oncologists Working Group of the Italian Association of Medical Oncology (AIOM)

Background The professional gender gap is increasingly recognised in oncology. We explored gender issues perception and gender influence on professional satisfaction/gratification among young Italian oncologists. Methods Italian oncologists aged ≤40 years and members of the Italian Association of Medical Oncology were invited to participate in an online survey addressing workload/burnout, satisfaction in professional abilities and relations, relevant factors for professional gratification, and gender barriers. ‡ 2 test for general association or ‡ 2 test for trend was used to analyse the data. Results 201 young oncologists participated in the survey: 67% female, 71% aged 30-40 years, 41% still in training and 82% without children. Women and men were equally poorly satisfied by the relations with people occupying superior hierarchical positions. There was heterogeneity between women and men in current (p=0.011) and expected future (p=0.007) satisfaction in professional abilities: women were more satisfied by current empathy and relations with colleagues and were more confident in their future managerial and team leader skills. The most important elements for professional gratification indicated by all participants were, in general, work-life balance (36%) and intellectual stimulation/research (32%); specifically for women, work-life balance (48%) and intellectual stimulation/research (20%); and specifically for men, career (29%) and social prestige/recognition (26%). Heterogeneity within the same gender emerged. For example, the elements indicated by men as the most important were intellectual stimulation/research (39%) and work-life balance (21%) in general, versus social prestige/recognition (24%) and career (24%), respectively, specifically for men (p<0.0001). More women versus men perceived gender issue as an actual problem (60% vs 38%, p=0.03); men underestimated gender barriers to women's career (p=0.011). Conclusions Satisfaction in professional abilities varied by gender. Work-life balance is important for both women and men. Stereotypes about gender issues may be present. Gender issue is an actual problem for young oncologists, mostly perceived by women

Produção e comercialização de madeira de plantios florestais na região do Alto Uruguai, RS.

Edição especial de Erva-mate

Metformin and Everolimus: A Promising Combination for Neuroendocrine Tumors Treatment

Introduction: Treatment options for neuroendocrine tumors (NETs) are rarely curative, as NETs frequently show resistance to medical therapy. The use of everolimus, an mTOR inhibitor, is limited by the development of resistance, probably due to the activation of Akt signaling. In this context, the antidiabetic drug metformin is able to inhibit mTOR, providing a rationale for the use of metformin and everolimus in combination. Methods: We investigated the effects of the metformin and everolimus combination on NET cell proliferation, apoptosis, colony formation, cell viability, NET spheroids growth and the involvement of the Akt and mTOR pathways, and also developed everolimus-resistant NET cells to further study this combination. Results: Metformin and everolimus in combination are more effective than monotherapy in inhibiting pancreatic NET (PAN-NET) cell proliferation (-71% \ub1 13%, p < 0.0001 vs. basal), whereas no additive effects were observed on pulmonary neuroendocrine tumor (PNT) cell proliferation. The combinatorial treatment is more effective than monotherapy in inhibiting colony formation, cell viability, NET spheroids growth rate and mTOR phosphorylation in both NET cell lines. In a PAN-NET cell line, metformin did not affect Akt phosphorylation; conversely, it significantly decreased Akt phosphorylation in a PNT cell line. Using everolimus-resistant NET cells, we confirmed that metformin maintained its effects, acting by two different pathways: Akt-dependent or independent, depending on the cell type, with both leading to mTOR suppression. Conclusions: Considering the promising effects of the everolimus and metformin combination in NET cells, our results provide a rationale for its use in NET patients

Dog erythrocyte antigens (DEA) 1, 4, 7 and suspected naturally occurring anti-DEA 7 antibodies in italian corso dogs

We sought to determine the prevalence of dog erythrocyte antigen (DEA) 1, 4 and 7 and naturally occurring anti-DEA7 antibodies in Italian Corso dogs. In addition, we correlated DEAs with different epidemiologic variables, compared the prevalence of DEAs against other canine populations and assessed the risk of sensitisation and transfusion reactions (TRs) following unmatched transfusion. Blood samples from 100 Corso dogs were evaluated for DEA 1, 4, 7 and naturally occurring anti-DEA 7 antibodies. Seventy-one percent of samples were DEA 1-negative, 100% tested DEA 4-positive, and 95% tested DEA 7-negative. Suspected anti-DEA7 antibodies were found in 32% dogs. The DEA 1 and 7-negative phenotypes were significantly more common than in most canine populations. When a previously tested Italian canine population was considered as blood donors for Corso dogs, the risk of DEA 1 sensitisation using DEA 1 untyped blood was 29%, and of acute haemolytic TRs after a second untyped DEA 1-incompatible transfusion was 8%. The potential for delayed TRs between DEA 7-negative Corso dogs with suspected naturally occurring anti-DEA 7 antibodies receiving untyped DEA 7-positive blood was 11%. Conversely, when Corso dogs were blood donors for the same population, the risk of DEA 1 sensitisation was 17% and the risk of an acute haemolytic TR after a second DEA 1-incompatible blood transfusion was 3%. Corso dogs can be suitable blood donors. Additional studies are needed to clarify whether the high prevalence of naturally occurring anti-DEA 7 antibodies in this breed could increase their risk of delayed TRs when they are blood recipients

Random walk through fractal environments

We analyze random walk through fractal environments, embedded in 3-dimensional, permeable space. Particles travel freely and are scattered off into random directions when they hit the fractal. The statistical distribution of the flight increments (i.e. of the displacements between two consecutive hittings) is analytically derived from a common, practical definition of fractal dimension, and it turns out to approximate quite well a power-law in the case where the dimension D of the fractal is less than 2, there is though always a finite rate of unaffected escape. Random walks through fractal sets with D less or equal 2 can thus be considered as defective Levy walks. The distribution of jump increments for D > 2 is decaying exponentially. The diffusive behavior of the random walk is analyzed in the frame of continuous time random walk, which we generalize to include the case of defective distributions of walk-increments. It is shown that the particles undergo anomalous, enhanced diffusion for D_F < 2, the diffusion is dominated by the finite escape rate. Diffusion for D_F > 2 is normal for large times, enhanced though for small and intermediate times. In particular, it follows that fractals generated by a particular class of self-organized criticality (SOC) models give rise to enhanced diffusion. The analytical results are illustrated by Monte-Carlo simulations.Comment: 22 pages, 16 figures; in press at Phys. Rev. E, 200