102,082 research outputs found
Nonlinear optical properties of Au-Ag nanoplanets made by ion beam processing of bimetallic nanoclusters in silica
No full textThe nonlinear absorption of Au-Ag nanoplanets made by Ar irradiation of bimetallic nanoclusters in silica has been experimentally investigated by means of the single beam z-scan technique. The measurements have been performed in the picoseconds regime in order to isolate the fast electronic contribution to the third-order nonlinearity. The results reveal large nonlinear absorption properties of these systems, characterized by the concomitance of saturable and reverse saturable absorption. A phenomenological expression has been developed to fit the z-scan curves and to quantitatively determine the nonlinear optical parameters. © 2010 Elsevier B.V. All rights reserved
Nanopatterning of silica with mask-assisted ion implantation
No full textIn the present paper we combined ion implantation and nanosphere lithography to regularly dope, by a mask-assisted process, a SiO2 substrate with rare earth ions (Er) by ion implantation and to fabricate by sputtering a plasmonic 2D periodic array of Au nanostructures on the silica surface spatially coupled to the implanted Er3+ ions. The aim of this work is to study how Er3+ emission at 1.5 μm can be affected by the interaction with a plasmonic nanostructure. In particular we have found a variation of the radiative lifetime of the Er3+ emission and a change from single exponential to bi-exponential of the luminescence intensity decay. © 2010 Elsevier B.V. All rights reserved
Nonlinear optical properties of Au–Ag nanoplanets made by ion beam processing of bimetallic nanoclusters in silica
No full textThe nonlinear absorption of Au–Ag nanoplanets made by Ar irradiation of bimetallic nanoclusters in silica has been experimentally investigated by means of the single beam z-scan technique. The measurements have been performed in the picoseconds regime in order to isolate the fast electronic contribution to the third-order nonlinearity. The results reveal large nonlinear absorption properties of these systems, characterized by the concomitance of saturable and reverse saturable absorption. A phenomenological expression has been developed to fit the z-scan curves and to quantitatively determine the nonlinear optical parameters
How to predict major injuries: an epidemiological approach.
No full textA better understanding of trauma epidemiology may allow to enhance the organisation of trauma systems with a potentially relevant impact on the level of trauma care. A one year epidemiology study (1st March 1998-28th February 1999) was planned in Friuli Venezia Giulia with the aim to collect all prehospital, hospital and outcome data of patients who sustained a major trauma (ISS > 15) within the regional border. In 12 months 15,429 traumatized patients (14,108 residents) were admitted to any one of the Regional hospitals. Over 1% of the whole population sustained injuries severe enough to cause hospital admission. 630 people (77.3% male, 27.7% female average age 42 ys) had a major trauma. The incidence of major trauma is 525 per million people per year. RTA was by far the most important cause of major injuries (78.6%) followed by work accidents (6.8%), domestic (5.9%) and sport accidents (1.9%). Only 1.2% of all the major injuries was the consequence of interpersonal violence. One hundred-sixty-six trauma victims died on the spot (149) or before hospital arrival (17). 464 patients with major injuries reached the hospital alive. More than two third of the patients with ISS > 15, suffered from a multiple trauma. 70% had a severe injury to the head (AIS > or = 3). Head trauma occurred as an isolated injury in only 35.3%. Hospital mortality within 30 days from admission (trauma death) was 25.1%. The results of the follow-up at 6 months are still incomplete. However the preliminary data clearly show that a high percentage of the patients who were discharged alive from the ICU had a good neurologic recovery
A population based study on pneumothorax in severely traumatized patients
No full textBACKGROUND:
Pneumothorax (PNX) is a recognized cause of preventable deaths in trauma patients. Our objective was to determine the incidence of traumatic PNX, the characteristics of its victims, and the treatment they receive.
METHODS:
The study consisted of data set of a population-based study on major trauma.
RESULTS:
The incidence of PNX was 81 per 1 million population per year, mostly caused by transport accidents. PNX victims generally had multiple injuries, and they showed on-scene clinical parameters worse than victims of other chest injuries of comparable severity. Fifty-three percent of PNXs were drained during the prehospital and early (< 2 hours) hospital course. There was no uniformity of treatment among different types of rescue facilities, some of them never performing decompression despite clinical need. The z statistic for mortality was -0.63.
CONCLUSION:
PNX can be expected in one in five major trauma victims found alive. PNX is associated with a peculiar on-scene instability. Early decompression is often required. The effects of wider access to prehospital decompression and the reasons for its uneven availability in our setting need elucidation. Nevertheless, the present mortality follows the international standards
Structural modification of Au-Co thin films induced by annealing in oxidizing atmosphere
No full textIncidence, Diagnosis, Treatment, and Outcomes of True Superficial Artery Aneurysms
No full textBackground: True superficial femoral artery aneurysms (SFAAs) do not occur frequently but carry a high risk of limb loss when they are complicated with thrombosis, distal embolization or rupture. Large aneurysms can also exert a mass effect, compressing adjacent veins and nerves. We performed an updated review of the literature with regard to their incidence, diagnosis, treatment, and outcomes over the years. Methods: A MEDLINE, Excerpta Medica Database (EMBASE) search of papers reporting SFAAs was conducted. Studies reported in the literature were considered for the review regardless of their nature and the number of participants. The available data regarding patient demographics, method of diagnosis, size, location, clinical presentation, therapy, and outcomes were examined. Results: Searching from 1967 to the present, we identified 59 papers reporting true SFAAs. Forty-one papers were case reports with 1 case each, 9 papers with 2 cases each and 9 papers reporting case series with more than 3 cases. There was 1 study reporting data on the management of asymptomatic SFAAs. We identified 164 SFA aneurysms, and 84.4% were symptomatic. The mean age of patients at the presentation was 70.2 years (range, 27–96) and 89.4% were men. SFAAs were diagnosed earlier in patients with connective tissue disorders, with a mean age of 35 years (range, 29–43). In 60.2 % of cases are present symptoms related to mass compression, 26,8% with rupture, and 27,3% of cases with ischemic symptoms. Endovascular approach was chosen in 52.6% of SFAAs reported in the last 5 years. Conclusions: The data in the available literature are poor regarding the management of asymptomatic aneurysms, and the conclusions are based mainly on the symptomatic aneurysms reported. Most SFAAs present mainly with symptoms due to mass compression and rupture rather than ischemic symptoms. The endovascular approach is becoming more popular and could become the preferred choice
Rich Broadband Chiral Behavior in Low-cost Plasmonic Nanostructures
No full textPlasmonic nanostructures with broken symmetry have been proposed for the control of the circular polarization at the nanoscale, important for applications spanning from chiral sensing to circularly polarized nanosources. We recently demonstrated that the low-cost self-assembling nanosphere lithography, combined with tilted metal deposition, opens new possibilities for the design and fabrication of chiral nanostructures. Starting from polystyrene nanospheres (PNS) covered by asymmetric metallic shell, we measured chirality in absorption at 633 nm [1]. We discovered that the nanohole array (NHA) formed due to the shadow, can exhibit chiral properties in a broad near-infrared range [2] , [3]
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