251 research outputs found
Seasonal dependence of cadmium molecular effects on Mytilus galloprovincialis (Lamarck, 1819) protamine-like protein properties
No full textMussels have a seasonal reproduction and cadmium is a common stressor in estuarine and coastal environments. In previous studies, we have shown that exposure to subtoxic doses of cadmium produced alterations in the properties of winter Mytilus galloprovincialis sperm protamine-like (PL) proteins. In this study, it was analyzed the possibility that these cadmium effects may be seasonal. Winter and summer mussels were exposed to CdCl2 , and it was tested the PL-proteins for cadmium bioaccumulation, electrophoretic pattern, DNA binding, and potentiality to induce DNA oxidative damage. It was found that cadmium exposure did not produce the same effects on PL-proteins of summer mussels that were produced on PL-proteins of winter mussels, that is: cadmium bioaccumulation, alterations in the acetic acid-urea polyacrylamide gels (AU-PAGE) and sodium dodecyl sulfate-PAGE pattern, a reduced DNA binding affinity and the ability to induce DNA oxidative damage. PL-proteins from summer mussels, apart from not being affected by all the abovementioned effects of cadmium, also showed a very low DNA binding affinity, independent of cadmium exposure. This study reveals clock-associated seasonal responses to cadmium in M. galloprovincialis. Understanding the mechanisms through which environmental signals guide biological rhythms is fundamental to understanding the seasonal sensitivity of this bioindicator, to use M. galloprovincialis in appropriate seasonal periods
Dipendenza dal pH e dalla presenza di ioni fosfato della cinetica di rilascio del CO dalla mioglobina di Nassa mutabilis
No full textPreliminary aerothermal design of axial compressors
No full textThis dissertation documents a compressor preliminary design study conducted by the author
in fulfilment of his MSc thesis requirements. The compressor is intended for a new
development engine within the 20Klbf thrust category, planned to be used on a short-haul
aircraft, namely the ERJ-190.
A market research suggests that there exists a definite opportunity for a commercially
profitable engine within this thrust class. Furthermore, the proposed new engine is projected
to outperform current production engines on critical issues such as fuel efficiency and
operability.
By and large, the objectives of this work have been achieved and a compressor design and
layout is suggested, which matched or exceeded all the initial requirements. The quality of
the results from this study are thought to be of sufficient detail to allow a further, more
detailed development study to resolve some subtle pending issues. It is expected that, some
compressor stages may have to be altered slightly during detailed design to augment their
performance and ease of manufacture and assembly.
Throughout this study, the importance of the compressor design figure of merits, pertaining
to a short haul engine, has been outlined and their interaction on the design process is well
documented. Furthermore, some rather unorthodox objectives such as compressor
performance retention and reliability have been discussed. The author approached these
subjects in an innovative way due to the limited non-proprietary knowledge available on
these issues, especially considering their implications within preliminary design.
Furthermore, the author developed and tested a new preliminary turbomachinery design code,
named Turbodev, which can be used as an aid in future compressor design endeveours.
Turbodev can handle most types of compressor layouts and generates an overall aerodynamic
assessment of the turbomachinery performance.
In conclusion; this documentation and the associated literature review aim to provide the
reader with an overview of the work done and yield a better understanding of the decisions
that face any design bureau when developing a new or modified engine component.The research work disclosed in this publication is partially funded by the
Strategic Educational Pathways Scholarship Scheme (Malta). The
scholarship is part-financed by the European Union – European Social
Fund under Programme II – Cohesion Policy 2007-2013
Il ciclo cellulare
No full textRevisione e aggiornamento della traduzione italiana sulla IV edizione inglese del capitolo numero 1
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