7,852 research outputs found

    From Finite to Linear Elastic Fracture Mechanics by Scaling

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    In the setting of finite elasticity we study the asymptotic behaviour of a crack that propagates quasi-statically in a brittle material. With a natural scaling of size and boundary conditions we prove that for large domains the evolution with finite elasticity converges to the evolution with linearized elasticity. In the proof the crucial step is the (locally uniform) convergence of the non-linear to the linear energy release rate, which follows from the combination of several ingredients: the Γ\Gamma-convergence of re-scaled energies, the strong convergence of minimizers, the Euler-Lagrange equation for non-linear elasticity and the volume integral representation of the energy release

    Sc substitution for Mg in MgB2: effects on Tc and Kohn anomaly

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    Here we report synthesis and characterization of Mg_{1-x}Sc_{x}B_{2} (0.12T_{c}>6 K. We find that the Sc doping moves the chemical potential through the 2D/3D electronic topological transition (ETT) in the sigma band where the ``shape resonance" of interband pairing occurs. In the 3D regime beyond the ETT we observe a hardening of the E_{2g} Raman mode with a significant line-width narrowing due to suppression of the Kohn anomaly over the range 0<q<2k_{F}.Comment: 8 pages, 4 EPS figures, to be published in Phys. Rev.

    Continuous improvement planning through sustainability assessment of product-service systems

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    The paper presents a methodology for the integrated sustainability assessment of a product-service system lifecycle, with the purpose to support continuous improvement on the side both of the manufacturer and of the user. Its eight steps are an extension of ISO 14040 life cycle assessment and consider all three sustainability dimensions – economic, environmental and social – and a service perspective, using the service unit. A set of indicators for the three dimensions, aligned to the service unit concept, is proposed based on literature suggestions

    Le api svelano il mistero delle fonti di emissione di particolato inquinante

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    Si tratta di una ricerca che è durata due anni, ed è stata pubblicata sul numero di luglio 2015 della Rivista scientifica internazionale Plos One. Gli autori: Ilaria Negri, Marco Pellecchia (Koiné - Consulenze Ambientali S.n.c., Parma, Italy), Christian Mavris (Department of Earth Sciences, Natural History Museum, London, United Kingdom), Gennaro Di Prisco, Emilio Caprio (Dipartimento di Agraria, Laboratorio di Entomologia E. Tremblay, Università degli Studi di Napoli Federico II, Portici - Napoli). Nello studio scientifico i ricercatori dimostrano che le api si comportano anche come “campionatori” attivi di particolato atmosferico, i cosiddetti PM (dall’inglese “Particulate Matter”), di cui sono ricche le nostre città come troppo spesso avvertono i dati dell’Agenzia Regionale di Protezione dell’Ambiente (ARPA). Dice che l’Iglesiente (Iglesias, Sardegna) è inquinato, fortemente contaminato da metalli pesanti come il piombo e il bario. E svela poi che la salute di chi ci vive potrebbe essere compromessa, se non lo è già, anche dall’alta concentrazione di ferro, silicio e alluminio. Rivela ancora, con scientifica precisione, da dove provengono le micro particelle di queste impercettibilissime polveri: dalle miniere dell’Iglesiente e dalle industrie di Portovesm

    Insights on Non-Candida albicans Candida species virulence factors

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    Trends in cancer mortality in the Americas, 1970-2000

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    Background: Data and statistics on cancer mortality over the last decades are available for most developed countries, while they are more difficult to obtain, in a standardized and comparable format, for countries of Latin America. Patients and methods: Age standardized (world population) mortality rates around the year 2000, derived from the WHO database, are presented for 14 selected cancers and total cancer in 10 countries of Latin America, plus, for comparative purposes, Canada and the USA. Trends in mortality are also given over the period 1970-2000. Results: In 2000, the highest total cancer mortality for males was observed in Argentina and Chile, with rates comparable to those of Canada and the USA, i.e. about 155/100 000. For women, Chile and Cuba had the highest rates in Latin America (114 and 103/100 000, respectively), again comparable to those of North America (around 105/100 000). These reflect the comparatively high mortality from cancer of the stomach (for Chile), lung and intestines (for Argentina) in men, and of stomach and uterus (for Chile), intestines and lung (for Cuba) in women. Colombia, Ecuador and Mexico had the lowest total cancer mortality for men, due to low mortality from stomach, colorectal and lung cancer. For women, the lowest rates were in Brazil and Puerto Rico, reflecting their low stomach and cervical cancer rates. In Argentina, Chile, Colombia, Costa Rica and Venezuela cancer mortality rates tended to decline, particularly in men. Rates were stable in Ecuador and Puerto Rico, and were increasing in Mexico and Cuba. Conclusions: Mortality from some common cancers (including colorectal and lung) is still low in Latin America compared with Canada and the USA, and decreasing trends have been observed in the last decades for some cancer sites (including stomach, uterus, lung and other tobacco-related cancers) in several countries. However, mortality from female lung and breast cancers has been increasing in most countries of Latin America, and several countries still show an extremely elevated mortality from cancer of the cervix. Selected neoplasms amenable to treatment, including testis and leukemias, also show unsatisfactory trends in Latin Americ

    Risk factors for adenocarcinoma of the cervix: a case-control study.

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    To assess risk factors for cervical adenocarcinoma data were collected in a case-control study of 39 cases and 409 controls conducted in the greater Milan area. Questions were asked about personal characteristics and habits, gynaecologic and obstetric data, history of lifetime use of oral contraceptives and other female hormones, and general indicators of sexual habits (age at first intercourse and total number of sexual partners). The relative risk of cervical adenocarcinoma increased with number of births and abortions, early age at first birth and early age at first intercourse. These estimates did not materially change after adjustment for the potential reciprocal confounding effect. Further, there was a positive association with overweight, but an apparent association with lower education was not significant. No relationship emerged with oral contraceptive use. Thus, despite the similarities with the epidemiology of squamous cell cancer, reproductive patterns and other factors related to the risk of endometrial cancer (i.e., overweight) seem to play an important role in the risk of adenocarcinoma of cervix uteri

    Honey Bees (Apis mellifera, L.) as Active Samplers of Airborne Particulate Matter

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    © 2015 Negri et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. [CC by 4.0] The attached file is the published version of the article

    Adhesion of non-Candida albicans Candida spp to urinary epithelial cells

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    Non-Candida albicans Candida (NCAC) spp, are nowadays responsible for more than 50% of Candida infections and it has been shown that the most prevalent NCAC spp are C.tropicalis, C. parapsilosis and C. glabrata. An important step on NCAC spp infection is their ability to adhere to the host tissues. Therefore, the aim of this study was to evaluate the ability of C.tropicalis, C. parapsilosis and C. glabrata to adhere to a urinary epithelial cell line (TCC-SUP). The ability of C.tropicalis ATCC 750, C. parapsilosis ATCC 2201, C. glabrata ATCC 2001 and C. albicans SC5413 to adhere to TCC-SUP cells was evaluated after 2 and 24h. For that, yeast cells (1x107 cell/ml) were incubated with a confluent layer of epithelial cells at 37 ºC and 5 % of CO2. The number of yeast cells adhered to the epithelial cells was determined using an adaptation of the Crystal Violet (CV) staining method. Additionally, the epithelial cell activity was determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2- (4-sulfophenyl)-2H-tetrazolium (MTS) viability assay. After 24h of incubation the number of yeasts adhered to epithelial cells was higher than after 2h, unexpectedly except for C. glabrata. Nevertheless, after 24 h, C. glabrata extent of adhesion was still higher than C. tropicalis and C. parapsilosis. This particular behavior of C. glabrata was also observed after 2 h of adhesion, showing a higher number of adhered cells in comparison with the other NCAC spp, which behaved very similarly. The trend observed by CV staining does not seem to be reflected on the metabolic activity of the epithelial cells.The main conclusion of the present work is that NCAC spp are biofilm producers on silicone, and that the adhesion and biofilm formation ability appear to be species and strain dependent
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