1,720,986 research outputs found
Risposta dinamica di un sistema elastico a contatto con una superficie ruvida mobile
No full textLa presente memoria ha come oggetto lo studio dei fenomeni dinamici osservabili quando due o piu` componenti di un sistema meccanico scorrono con attrito l’uno sull’altro, oppure contro una superficie mobile. In particolare, si propone un semplice modello composto da un blocco rigido, collegato ad una molla elastica, libero di scorrere su una superficie scabra che, a sua volta, si muove seguendo una legge del moto di tipo sinusoidale. Il contatto tra il blocco e la superficie e` caratterizzato invece da una legge di attrito di tipo coulombiano.
Il modello proposto e` utilizzato per analizzare in dettaglio le possibili evoluzioni del sistema, valutando l’influenza sul moto dei principali parametri, quali, ad esempio, la frequenza naturale del sistema blocco-molla, l’ampiezza e la frequenza delle oscillazioni della superficie, etc. Il modello, pur nella sua grande semplicita`, sembra potenzialmente in grado di riprodurre alcuni dei principali fenomeni dinamici che generalmente si osservano nei casi di interesse pratico. Inoltre, e` possi- bile ricostruire in dettaglio sia la sequenza delle fasi di aderenza e di scorrimento del blocco, sia l’andamento nel tempo delle forze reattive che si scambiano la massa e la superficie in moto relativo fra loro
Risk of transmission of vaccine-preventable diseases in healthcare settings
Full text linkThe transmission of infectious agents within healthcare settings is a priority public health problem. Although the main burden of healthcare-associated infections is commonly caused by Gram-negative bacteria and fungi, vaccine-preventable diseases represent an additional infectious risk for patients attending healthcare facilities. Hepatitis B, rotavirus gastroenteritis, influenza, measles, pertussis and pneumococcal and meningococcal invasive bacterial infections still represent a threat, notwithstanding the presence of universal vaccination programs. For this reason, healthcare worker immunization is an important strategy to limit the risk of vaccine-preventable diseases in such a fragile population
Impact of mandatory law on vaccine hesitancy spectrum: The case of measles vaccine catch-up activities in Tuscany, Italy
Full text linkCommentary on the impact of 2017 Italian law mandating ten vaccinations for children
Cutaneous ulcers associated with hydroxyurea therapy
No full textHydroxyurea is an antitumoral drug mainly used in the treatment of Philadelphia chromosome-negative myeloproliferative syndromes and sickle-cell disease. Ulcers represent a rare but severe long-term adverse effect of hydroxyurea therapy. Hydroxyurea-induced ulcers are often multiple and bilateral, typically developing in the perimalleolar region, although any cutaneous district is potentially affected. They generally look small, well-defined, shallow with an adherent, yellow, fibrinous necrotic base. A constant finding is also an extremely intense, treatment-resistant pain accompanying these ulcerations. Withdrawal of the drug generally leads to spontaneous healing of these lesions. Care providers tend to show insufficient awareness of this highly debilitating cutaneous side effect, and late or missed diagnoses are frequent. Instead, regular dermatologic screening should be performed on hydroxyurea-treated patients. This article will present a comprehensive review of indexed case reports and clinical studies, followed by a discussion about treatment options aiming at increasing knowledge about this specific topic. © 2013 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved
Impact of mandatory law on vaccine hesitancy spectrum: The case of measles vaccine catch-up activities in Tuscany, Italy
Full text link- …
