653 research outputs found
Initial/boundary-value problems of tumor growth within a host tissue
This paper concerns multiphase models of tumor growth in interaction with a
surrounding tissue, taking into account also the interplay with diffusible
nutrients feeding the cells. Models specialize in nonlinear systems of possibly
degenerate parabolic equations, which include phenomenological terms related to
specific cell functions. The paper discusses general modeling guidelines for
such terms, as well as for initial and boundary conditions, aiming at both
biological consistency and mathematical robustness of the resulting problems.
Particularly, it addresses some qualitative properties such as a priori
nonnegativity, boundedness, and uniqueness of the solutions. Existence of the
solutions is studied in the one-dimensional time-independent case.Comment: 30 pages, 5 figure
Vitamin E in Viral Inactivated Vaccines
Abstract This research aimed at verifying whether vitamin E added to inactivated and emulsified vaccines enhances the immune response to viral antigens in chicken. Three hundred and twenty broilers (males and females) and 16 types of vaccines, varying in viral antigen [Newcastle disease virus, egg drop syndrome 1976 virus (EDS76V), and infectious bursal disease virus] and vitamin E amount (replacing 10, 20, and 30% of mineral oil) were used. Results show that vaccines with vitamin E, especially when it replaces 20 or 30% of mineral oil, induces a more rapid and higher antibody response than control vaccines. An adjuvant effect of vitamin E was also present in viral vaccine lacking bacterial antigens. Apart from vitamin E content, the Newcastle disease virus and infectious bursal disease virus monovalent vaccines induced higher titers of specific circulating antibodies in birds than did trivalent vaccines
The Relevance of Academic Libraries in the Twenty-First Century
The biggest challenge facing the library profession in the twenty-first century is staying relevant to its users. It is often stated that the Internet and Google have changed librarianship. This challenge, while significant, does not mean that libraries will go away. It is causing us to re-evaluate what we do, how we do it, and what role libraries have in the academy and in our culture at large. This column addresses some of the ways in which academic libraries can stay relevant throughout the twenty-first century
Modification of cheese flavour through the use of surface microbiota
Surface microorganisms in surface-ripened cheese, combined with lactic acid bacteria, contribute to lipolysis and proteolysis, degradation of free fatty acids and free amino acids, and the metabolism of lactose, citrate and lactate, with a consequent biosynthesis of volatile flavour compounds. The intense metabolic activity of the yeasts and Gram-positive bacteria on the cheese surface is evident in surface-ripened cheese, where the resident surface microbial population is responsible for the characteristic strong flavour, typical for this cheese variety. Although cheese is a widely studied fermented food, the biochemical mechanisms which lead to the biosynthesis of volatile compounds, and the development of cheese flavour, are not completely clear and need to be explained. Therefore, the aim of the studies in this thesis was to investigate the development of flavour volatile compounds in cheese, produced by cheese microbiota, both as single strains in model systems, and when applied to cheese curd surface as simple or more complex culture mixes containing yeasts and Gram-positive bacteria. Through the use of the metagenomic and enzymatic assays, it has been possible to investigate the potential flavour-forming ability of the cheese microorganisms, and correlate the results to volatile flavour compounds detected with gas-chromatography. Our results have shown how variations in the microbial population influence the flavour development in cheese during ripening. This research may be of industrial benefit for the manipulation of the microbiota and the production of fermented food with specific flavour characteristics
Duodenal-Jejunal Bypass and Jejunectomy Improve Insulin Sensitivity in Goto-Kakizaki Diabetic Rats Without Changes in Incretins or Insulin Secretion
Gastric bypass surgery can dramatically improve type 2 diabetes. It has been hypothesized that by excluding duodenum and jejunum from nutrient transit, this procedure may reduce putative signals from the proximal intestine that negatively influence insulin sensitivity ( S I ). To test this hypothesis, resection or bypass of different intestinal segments were performed in diabetic Goto-Kakizaki and Wistar rats. Rats were randomly assigned to five groups: duodenal-jejunal bypass (DJB), jejunal resection (jejunectomy), ileal resection (ileectomy), pair-fed sham-operated, and nonoperated controls. Oral glucose tolerance test was performed within 2 weeks after surgery. Baseline and poststimulation levels of glucose, insulin, glucagon-like peptide 1 (GLP-1), and glucose-dependent insulinotropic polypeptide (GIP) were measured. Minimal model analysis was used to assess S I . S I improved after DJB ( S I = 1.14 ± 0.32 × 10 −4 min −1 ⋅ pM −1 ) and jejunectomy ( S I = 0.80 ± 0.14 × 10 −4 min −1 ⋅ pM −1 ), but not after ileectomy or sham operation/pair feeding in diabetic rats. Both DJB and jejunal resection normalized S I in diabetic rats as shown by S I levels equivalent to those of Wistar rats ( S I = 1.01 ± 0.06 × 10 −4 min −1 ⋅ pM −1 ; P = NS). Glucose effectiveness did not change after operations in any group. While ileectomy increased plasma GIP levels, no changes in GIP or GLP-1 were observed after DJB and jejunectomy. These findings support the hypothesis that anatomic alterations of the proximal small bowel may reduce factors associated with negative influence on S I , therefore contributing to the control of diabetes after gastric bypass surgery
Vitamin E as Adjuvant in Emulsified Vaccine for Chicks
Abstract Mineral oil was partially replaced with D, L-α-tocopheryl acetate (vitamin E) in bacterial and viral inactivated emulsified vaccines. Vitamin E increased the immune response to the viral antigen (Newcastle disease virus) used but not to the bacterial antigen (Escherichia coli) when its presence in the oil phase did not exceed 30%. Inoculated vitamin E may have enhanced the immune response by interacting with the immune-competent cells involved in the inflammatory reaction that followed inoculation of emulsified vaccines
Does coffee protect against hepatocellular carcinoma?
We analysed the relation between coffee consumption and hepatocellular carcinoma in two case-control studies conducted between 1984 and 1998 in Italy and Greece, including 834 cases and 1912 controls. Compared to non coffee drinkers, the multivariate odds ratio was 0.7 for drinkers of three or more cups per day
Visible-Light Assisted Covalent Surface Functionalization of Reduced Graphene Oxide Nanosheets with Arylazo Sulfones
We present an environmentally benign methodology for the covalent functionalization (arylation) of reduced graphene oxide (rGO) nanosheets with arylazo sulfones. A variety of tagged aryl units were conveniently accommodated at the rGO surface via visible-light irradiation of suspensions of carbon nanostructured materials in aqueous media. Mild reaction conditions, absence of photosensitizers, functional group tolerance and high atomic fractions (XPS analysis) represent some of the salient features characterizing the present methodology. Control experiments for the mechanistic elucidation (Raman analysis) and chemical nanomanipulation of the tagged rGO surfaces are also reported
Listening to Music in the First, but not the Last 1.5 km of a 5-km Running Trial Alters Pacing Strategy and Improves Performance
We examined the effects of listening to music on attentional focus, rating of perceived exertion (RPE), pacing strategy and performance during a simulated 5-km running race. 15 participants performed 2 controlled trials to establish their best baseline time, followed by 2 counterbalanced experimental trials during which they listened to music during the first (M-start) or the last (M-finish) 1.5 km. The mean running velocity during the first 1.5 km was significantly higher in M-start than in the fastest control condition (p < 0.05), but there was no difference in velocity between conditions during the last 1.5 km (p > 0.05). The faster first 1.5 m in M-start was accompanied by a reduction in associative thoughts compared with the fastest control condition. There were no significant differences in RPE between conditions (p > 0.05). These results suggest that listening to music at the beginning of a trial may draw the attentional focus away from internal sensations of fatigue to thoughts about the external environment. However, along with the reduction in associative thoughts and the increase in running velocity while listening to music, the RPE increased linearly and similarly under all conditions, suggesting that the change in velocity throughout the race may be to maintain the same rate of RPE increase.Australian Department of Education, Employment and Workplace RelationsAustralian Department of Education, Employment and Workplace Relation
Indoor mobile mapping system and crowd simulation to support school reopening because of covid-19: a case study
Occupancy analyses represent a crucial topic for building performance. At present, this is even true because of the pandemic emergency due to SARS-CoV-2 and the need to support the functional analysis of building spaces in relation to social distancing rules. Moreover, the need to assess the suitability of spaces in high occupancy buildings as the educational ones, for which occupancy evaluations result pivotal to ensure the safety of the end-users in their daily activities, is a priority. The proposed paper investigates the steps that are needed to secure a safe re-opening of an educational building. A case study has been selected as a test site to analyse the re-opening steps as required by Italian protocols and regulations. This analysis supported the school director of a 2-to-10 year old school and its team in the decision-making process that led to the safe school re-opening. Available plants and elevations of the building were collected and a fast digital survey was carried out using the mobile laser scanner technology (iMMS - Indoor Mobile Mapping System) in order to acquire three-dimensional geometries and digital photographic documentation of the spaces. A crowd simulation software (i.e. Oasys MassMotion) was implemented to analyse end-users flows; the social distance parameter was set in its proximity modelling tools in order to check the compliance of spaces and circulation paths to the social distancing protocols. Contextually to the analysis of users flows, a plan of hourly air changes to maintain a high quality of the environments has been defined
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