3,848 research outputs found

    Suono solido

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    Analisi e ricerche sulle possibilitĂ  di utilizzo del marmo per la progettazione di diffusori acustici e prodotti audio per la casa. Sviluppo di un prototipo di diffusore acustico in marmo ideato per ambienti interni

    Time-resolved optical studies, heat dissipation and melting of Ag and Au nanoparticle systems and arrays

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    Transient absorption spectroscopy has been extensively used in recent years to examine the temporal response of isolated nanoparticles (NPs) to the absorption of light [1]. These studies are largely based on the use of the surface plasmon resonance (SPR) to monitor characteristics of the NP such as electronic and lattice temperature, shape and morphology as a function of time. In the case of extended Au/Ag NP structures the plasmon resonance is strongly distorted due to the inter-particle coupling effects. For example, we have observed this effect in Rhodamine dye functionalized Au nanoparticles which undergo self-assembly to form nanostructures due to the interactions between the dye molecules attached to the surfaces of the nanoparticles. Indeed the SPR splits into two with one resonance remaining in the vicinity of that of the isolated AuNPs and is generally called the transverse SPR while a second resonance due to an extended excitation spanning across multiple particles appears to the lower energies. The precise spectral energy and shape of the extended plasmon resonance depends on the inter-particle distance, the particle disposition and the number of particles involved. When the plasmon band or interband spectral region of the NP is excited by an intense pulse the photon energy absorbed by the electrons is transferred to the lattice of the NP as heat through electron-phonon coupling. Depending on the intensity of the light pulse and thus the initial electron temperature a number of outcomes are possible. The first aim of this work is to use low intensity pump pulses to study the wavelength dependence of the sub 10 ps dynamics which reflects the electron-photon scattering within the nanoparticle structure. On the other hand, the interaction of more intense light with the NPs can modify the morphology of NP systems, for example by reshaping gold nanorods into nanospheres or, in general, mediate the synthesis of metallic nanostructures. At medium intensities the initial temperature is sufficient to induce melting of the NPs which can lead to morphological changes of the NP structure. Higher intensities can cause other effects such as photofragmentation of the NPs, release of stabiliser molecules from the surface of the NPs or even Coulomb explosion due to multiple ionisation events. The second aim of this work is to concentrate on the effects of medium intensity laser excitation of a self-assembled Au/Ag NP systems. The NP system is excited by a femtosecond laser pulse of different wavelengths allowing selective deposition of energy and the subsequent heat dissipation through phonon-phonon coupling and morphological changes are monitored in time by recording transient absorption spectra in the visible range. This wavelength range makes it possible to follow the phonon-phonon coupling effects on the recovery of the bleaching of both the transverse and extended plasmon resonances of the NP system. As the intensity of the pump pulse is increased it can be seen that the NPs are no longer able to dissipate all of the heat before arrival of subsequent laser pulses thus leading to melting of the NP structure and strong changes in the plasmon response of the system. The overall aim of this study is to fully understand the delocalized electron-phonon coupling in the extended plasmon region of the NP structures and to use this knowledge to control the melting in nanostructures. The methods developed can be useful for plasmon mediated nano-engineerin

    Lower mortality rate in elderly patients with community-onset pneumonia on treatment with aspirin

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    BACKGROUND: Pneumonia is complicated by high rate of mortality and cardiovascular events (CVEs). The potential benefit of aspirin, which lowers platelet aggregation by inhibition of thromboxane A2 production, is still unclear. The aim of the study was to assess the impact of aspirin on mortality in patients with pneumonia. METHODS AND RESULTS: Consecutive patients admitted to the University-Hospital Policlinico Umberto I (Rome, Italy) with community-onset pneumonia were recruited and prospectively followed up until discharge or death. The primary end point was the occurrence of death up to 30 days after admission; the secondary end point was the intrahospital incidence of nonfatal myocardial infarction and ischemic stroke. One thousand and five patients (age, 74.7±15.1 years) were included in the study: 390 were receiving aspirin (100 mg/day) at the time of hospitalization, whereas 615 patients were aspirin free. During the follow-up, 16.2% of patients died; among these, 19 (4.9%) were aspirin users and 144 (23.4%; P<0.001) were aspirin nonusers. Overall, nonfatal CVEs occurred in 7% of patients, 8.3% in nonaspirin users, and 4.9% in aspirin users (odds ratio, 1.77; 95% confidence interval, 1.03 to 3.04; P=0.040). The Cox regression analysis showed that pneumonia severity index (PSI), severe sepsis, pleural effusion, and PaO(2)/FiO(2) ratio <300 negatively influenced survival, whereas aspirin therapy was associated with improved survival. Compared to patients receiving aspirin, the propensity score adjusted analysis confirmed that patients not taking aspirin had a hazard ratio of 2.07 (1.08 to 3.98; P=0.029) for total mortality. CONCLUSIONS: This study shows that chronic aspirin use is associated with lower mortality rate within 30 days after hospital admission in a large cohort of patients with pneumonia

    Preliminary Investigation on the Ameliorative Role Exerted by D-Aspartic Acid in Counteracting Ethane Dimethane Sulfonate (EDS) Toxicity in the Rat Testis.

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    Herein is reported the first evidence of the protective role of D-aspartic acid (D-Asp) in preventing the toxic effect exerted by the alkylating agent ethane dimethane sulfonate (EDS) in the rat testis. We confirmed that EDS treatment specifically destroyed Leydig cells (LC), resulting in the drastic decrease of the serum testosterone level and producing morphological changes in the germinal tubules, i.e., altered organization of the epithelium, loss of cell contacts and the consequent presence of empty spaces between them, and a reduce number of spermatozoa. Moreover, an increase of TUNEL-positive germ cells, other than alteration in the protein level and localization of two LC “markers”, StAR and PREP, were observed. Interestingly, results obtained from rats pretreated with D-Asp for 15 days before EDS-injection showed that all the considered parameters were quite normal. To explore the probable mechanism(s) involved in the protection exerted by DAsp, we considered the increased oxidative stress induced by EDS and the D-Asp antioxidant effects. Thiobarbiturc acid-reactive species (TBARS) levels increased following EDS-injection, while no change was observed in the D-Asp + EDS treated rats. Our results showed that D-Asp may be used as a strategy to mitigate the toxic effects exerted by environmental pollutants, as endocrine disrupters, in order to preserve the reproductive function

    Novel agents for acute myeloid leukemia

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    Acute myeloid leukemia (AML) is a complex hematological disease characterized by genetic and clinical heterogeneity. Recent advances in the understanding of AML pathogenesis have paved the way for the development of new agents targeting specific molecules or mechanisms that contribute to finally move beyond the current standard of care, which is \u201c3 + 7\u201d regimen. In particular, new therapeutic options such as targeted therapies (midostaurin and enasidenib), monoclonal antibodies (gemtuzumab ozogamicin), and a novel liposomal formulation of cytarabine and daunorubicin (CPX-351) have been recently approved, and will be soon available for the treatment of adult patients with AML. In this review, we will present and describe these recently approved drugs as well as selected novel agents against AML that are currently under investigation, and show the most promising results as monotherapy or in combination with chemotherapy. The selection of these emerging treatments is based on the authors\u2019 opinion

    THERAPY-RELATED MYELOID NEOPLASMS: CONSIDERATIONS FOR PATIENTS’ CLINICAL EVALUATION

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    Therapy-related myeloid neoplasms (t-MNs) encompass a specific sub-group of myeloid malignancies arising after exposure to radio/cytotoxic agents for the treatment of unrelated diseases. Such malignancies present unique features, including advanced age, high comorbidities burden, and unfavorable genetic profiles. All these features justify the need for a specific diagnostic work-up and dedicated treatment algorithms. However, as new classification systems recognize the unique clinical characteristics exhibited by t-MN patients, how to assess fitness status in this clinical setting is largely unexplored. Optimizing fitness assessment would be crucial in the management of t-MN patients, considering that factors usually contributing to a worse or better outcome (like age, comorbidities, and treatment history) are patient-specific.In the absence of specific tools for fitness assessment in this peculiar category of AML, the aim of this review is to describe all those factors related to patient, treatment, and disease that allow planning treatments with an optimal risk/benefit ratio

    Hospitalization for pneumonia is associated with decreased 1-year survival in patients with type 2 diabetes results from a prospective cohort study

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    Diabetes mellitus is a frequent comorbid conditions among patients with pneumonia living in the community. The aim of our study is to evaluate the impact of hospitalization for pneumonia on early (30 day) and late mortality (1 year) in patients with type 2 diabetes mellitus. Prospective comparative cohort study of 203 patients with type 2 diabetes hospitalized for pneumonia versus 206 patients with diabetes hospitalized for other noninfectious causes from January 2012 to December 2013 at Policlinico Umberto I (Rome). Enrolled patients were followed up to discharge and up to 1 year after initial hospital admission or death. Overall, 203 patients with type 2 diabetes admitted to hospital for pneumonia were compared to 206 patients with type 2 diabetes admitted for other causes (39.3% decompensated diabetes, 21.4% cerebrovascular diseases, 9.2% renal failure, 8.3% acute myocardial infarction, and 21.8% other causes). Compared to control patients, those admitted for pneumonia showed a higher 30-day (10.8% vs 1%, P&lt;0.001) and 1-year mortality rate (30.3% vs 16.8%, P&lt;0.001). Compared to survivors, nonsurvivor patients with pneumonia had a higher incidence of moderate to severe chronic kidney disease, hemodialysis, and malnutrition were more likely to present with a mental status deterioration, and had a higher number of cardiovascular events during the follow-up period. Cox regression analysis found age, Charlson comorbidity index, pH&lt;7.35 at admission, hemodialysis, and hospitalization for pneumonia as variables independently associated with mortality. Hospitalization for pneumonia is associated with decreased 1-year survival in patients with type 2 diabetes, and appears to be a major determinant of long-term outcome in these patients

    Are Follow-Up Blood Cultures useful in the antimicrobial management of gram negative bacteremia? A reappraisal of their role based on current knowledge

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    Bloodstream infections still constitute an outstanding cause of in-hospital morbidity and mortality, especially among critically ill patients. Follow up blood cultures (FUBCs) are widely recommended for proper management of Staphylococcus aureus and Candida spp. infections. On the other hand, their role is still a matter of controversy as far as Gram negative bacteremias are concerned. We revised, analyzed, and commented on the literature addressing this issue, to define the clinical settings in which the application of FUBCs could better reveal its value. The results of this review show that critically ill patients, endovascular and/or non-eradicable source of infection, isolation of a multi-drug resistant pathogen, end-stage renal disease, and immunodeficiencies are some factors that may predispose patients to persistent Gram negative bacteremia. An analysis of the different burdens that each of these factors have in this clinical setting allowed us to suggest which patients’ FUBCs have the potential to modify treatment choices, prompt an early source control, and finally, improve clinical outcome

    Gram-negative septic thrombosis in critically ill patients: A retrospective case-control study

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    Background: Data on septic thrombosis caused by Gram-negative bacilli (GN-ST) in intensive care unit (ICU) patients are currently limited. Methods: The aim of this retrospective case–control study (matched 1:3) performed over a 15-month period on ICU patients with bacteraemia, associated (cases) or not (controls) with GN-ST, was to assess 30-day mortality and clinical/microbiological features of GN-ST. Results: During the study period, 16 patients with GN-ST and 48 controls were analyzed. Polytrauma was the cause of ICU admission in 12 (75%) cases and 22 (46%) controls (p = 0.019). In no case of septic thrombosis was surgical debridement performed. The site of venous thrombosis was more frequently in the lower limbs, associated with bone fracture in nine out of 12 (75%) cases. The median duration of bacteraemia (22 days vs 1 day; p 72 h was significantly associated with GN-ST (area under the curve (AUC) 0.95, sensitivity 0.996 and specificity 0.810; p < 0.001). Finally, 30-day mortality was 20% in cases and 67% in controls (p < 0.001). Conclusions: Critically ill patients with GN-ST showed specific clinical features. Despite delayed bacteraemia clearance, targeted antibiotic therapy plus anticoagulation usually provided clinical improvement and a low 30-day mortality rate
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