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1.
Phys Rev Lett ; 123(14): 143605, 2019 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-31702170

RESUMEN

The simple resonant Rabi oscillation of a two-level system in a single-mode coherent field reveals complex features at the mesoscopic scale, with oscillation collapses and revivals. Using slow circular Rydberg atoms interacting with a superconducting microwave cavity, we explore this phenomenon in an unprecedented range of interaction times and photon numbers. We demonstrate the efficient production of cat states, which are the quantum superposition of coherent components with nearly opposite phases and sizes in the range of few tens of photons. We measure cuts of their Wigner functions revealing their quantum coherence and observe their fast decoherence. This experiment opens promising perspectives for the rapid generation and manipulation of nonclassical states in cavity and circuit quantum electrodynamics.

3.
Phys Rev Lett ; 118(25): 253603, 2017 Jun 23.
Artículo en Inglés | MEDLINE | ID: mdl-28696734

RESUMEN

We realize a coherent transfer between a laser-accessible low-angular-momentum Rydberg state and the circular Rydberg level with maximal angular momentum. It is induced by a radio frequency field with a high-purity σ^{+} polarization resonant on Stark transitions inside the hydrogenic Rydberg manifold. We observe over a few microseconds more than 20 coherent Rabi oscillations between the initial Rydberg state and the circular level. We characterize these many-Rydberg-level oscillations and find them in perfect agreement with a simple model. This coherent transfer opens the way to hybrid quantum gates bridging the gap between optical communication and quantum information manipulations with microwave cavity and circuit quantum electrodynamics.

4.
Nanoscale ; 9(16): 5234-5243, 2017 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-28397932

RESUMEN

Prussian Blue Analog (PBA) nanoparticles were formed on a heterogeneous nanostructured surface made of an ordered nanoperforated titanium oxide thin film deposited on a gold layer. The study of the nanocomposite film by grazing-incidence wide angle X-ray scattering, infrared spectroscopy, scanning electron microscopy and atomic force microscopy shows that the PBA particles are precisely positioned within all the perforations of the oxide film over very large surface areas. Further investigation on the formation of the PBA particles demonstrates a decisive role of a heterogeneous nucleation of the coordination polymer driven by well-adjusted surfaces energies and reactant concentrations in the spatial positioning of the PBA particles. Thanks to the well-controlled positioning of the particles within the ordered nanoperforations, the latter were successfully used as nano crucibles for the local transformation of PBA into the corresponding metal alloy by heat treatment. The thin film heterostructure thus obtained, made of ferromagnetic islands isolated by diamagnetic walls, opens interesting perspectives for the design of magnetic storage devices.

6.
Nanoscale ; 7(12): 5371-82, 2015 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-25723817

RESUMEN

Capillary phenomena governing the mass-transport (capillary filling, condensation/evaporation) has been experimentally investigated in around 20 different silica thin films exhibiting various porosities with pores dimension ranging from 2 to 200 nm. Films have been prepared by sol-gel chemistry combined with soft-templating approaches and controlled dip coating process. Environmental ellipsometric porosimetry combined with electronic microscopy were used to assess the porosity characteristics. Investigation of lateral capillary filling was performed by following the natural infiltration of water and ionic liquids at the edge of a sessile drop in open air or underneath a PDMS cover. The Washburn model was applied to the displacement of the liquid front within the films to deduce the kinetic constants. The role of the different capillary phenomena were discussed with respect to the porosity characteristics (porosity vol%, pore dimensions and constrictions). We show that correlation between capillary filling rate and pore dimensions is not straightforward. Generally, with a minimum of constrictions, faster filling is observed for larger pores. In the case of mesopores (<50 nm in diameter), the presence of bottle necks considerably slows down the infiltration rate. At such a small dimension, evaporation/capillary condensation dynamics, taking place at the meniscus inside the porosity, has to be considered to explain the transport mode. This fundamental study is of interest for applications involving liquids at the interface of mesoporous networks such as nanofluidics, purification, separation, water harvesting or heat transfer.

7.
Science ; 340(6134): 827-31, 2013 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-23687040

RESUMEN

Piezoelectric nanostructured quartz films of high resonance frequencies are needed for microelectronic devices; however, synthesis methods have been frustrated by the inhomogeneous crystal growth, crystal twinning, and loss of nanofeatures upon crystallization. We report the epitaxial growth of nanostructured polycrystalline quartz films on silicon [Si(100)] substrates via the solution deposition and gelation of amorphous silica thin films, followed by thermal treatment. Key to the process is the combined use of either a strontium (Sr(2+)) or barium (Ba(2+)) catalyst with an amphiphilic molecular template. The silica nanostructure constructed by cooperative self-assembly permits homogeneous distribution of the cations, which are responsible for the crystallization of quartz. The low mismatch between the silicon and α-quartz cell parameters selects this particular polymorph, inducing epitaxial growth.

8.
Nanotechnology ; 24(14): 145702, 2013 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-23507583

RESUMEN

Magnetization reversal processes in Co/Pt multilayers prepared on nanoperforated templates are probed by magnetization relaxation measurements. The signature of pinning controlled domain wall movement as expected for percolated media is identified. This contrasts with the nucleation-type reversal mechanism of a Co/Pt reference film prepared on a smooth substrate. A zero field energy barrier of 93kBT is determined by fluctuation field measurements and is elucidated by micromagnetic calculations using the nudged elastic band method. This value is sufficiently large to qualify the material as a promising percolated medium.

9.
Phys Rev Lett ; 109(6): 064801, 2012 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-23006272

RESUMEN

We performed a combined secondary electron yield (SEY) and x-ray photoelectron spectroscopy study as a function of the electron dose and energy on a Cu technical surface representative of the LHC accelerator walls. The electron bombardment is accompanied by a clear chemical modification, indicating an increased graphitization as the SEY decreases. The decrease in the SEY is also found to depend significantly on the kinetic energy of the primary electrons. When low-energy primary electrons are employed (E≤20 eV), the reduction of the SEY is slower and smaller in magnitude than when higher-energy electrons are used. Consequences of this observation are discussed mainly for their relevance on the commissioning scenario for the LHC in operation at CERN (Geneva), but are expected to be of interest for other research fields.

10.
G Ital Med Lav Ergon ; 34(3 Suppl): 756-8, 2012.
Artículo en Italiano | MEDLINE | ID: mdl-23405771

RESUMEN

Urinary evaluations of drug consumption among workers having high risk of accident became compulsory in Italian legislation few years ago. We report results of 322.110 single urinary drug detections carried out between 2008 and 2011 on 35.789 subjects. We verified technical difficulties arisen during laboratory detections and organizational difficulties evidenced by Occupational Doctors during collections of samples. We screened 701 positive samples (1.96%), mostly to Cannabinoids and Cocaine, verified using first and second level screening according to national law. Many patients referred regular or irregular use of medicines active on Central Nervous System frequently ignoring their collateral effects. After the evidence of a positive result, during a second medical visit, many workers referred assumption of "natural diet supplements" acquired not in traditional commercial distributors. In two cases we have had the possibility of analyzing these supplements which have shown the presence of law concentrations of drugs in their compositions.


Asunto(s)
Accidentes de Trabajo/prevención & control , Salud Laboral/legislación & jurisprudencia , Detección de Abuso de Sustancias/legislación & jurisprudencia , Detección de Abuso de Sustancias/métodos , Trastornos Relacionados con Sustancias/diagnóstico , Trastornos Relacionados con Sustancias/orina , Humanos , Italia , Factores de Riesgo
12.
Nanotechnology ; 21(49): 495701, 2010 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-21071819

RESUMEN

We present a study on the magnetization reversal in Co/Pt multilayer films with an out-of-plane easy axis of magnetization deposited onto substrates with densely distributed perforations with an average period as small as 34 nm. Deposition of magnetic Co/Pt multilayers onto the nanoperforated surface results in an array of magnetic nanodots surrounded by a continuous magnetic film. Following the evolution of the magnetic domain pattern in the system, we suggest that domain walls are pinned on structural inhomogeneities given by the underlying nanoperforated template. Furthermore, a series of micromagnetic simulations was performed in order to understand the modification of the pinning strength of domain walls due to the magnetic interaction between nanodots and the surrounding film. The results of the simulations show that magnetic exchange coupling between the nanodots and the surrounding film strongly influences the pinning behavior of the magnetic domain walls which can be optimized to provide maximal pinning.

13.
Immunobiology ; 215(5): 341-7, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-19656587

RESUMEN

The clearance of apoptotic cells by phagocytes is a fundamental process during tissue remodeling and resolution of inflammation. In turn, the phagocytosis of apoptotic cells generates signals that suppress pro-inflammatory activation of macrophages. These events occur during the resolution phase of inflammation and therefore the malfunctioning of this process may lead to inflammation-related tissue damage. Here, we demonstrate that the calcium-binding protein S100A9, normally abundant in the cytoplasm of neutrophils and also released by apoptotic neutrophils, is involved in the suppression of macrophages after the uptake of apoptotic neutrophils. Both, spontaneous and induced production of inflammatory species (nitric oxide, hydrogen peroxide and TNF-alpha) as well as the phagocytic activity were inhibited when macrophages were in presence of apoptotic neutrophils, conditioned medium from neutrophil cultures or a peptide corresponding to the C-terminal region of S100A9 protein. On the other hand, macrophages kept in the conditioned medium of neutrophils that was previously depleted of S100A9 were shown to resume the activated status. Finally, we demonstrate that the calcium-binding property of S100A9 might play a role in the suppression process, since the stimulation of intracellular calcium release with ionomycin significantly reversed the effects of the uptake of apoptotic neutrophils in macrophages. In conclusion, we propose that S100A9 is a novel component of the regulatory mechanisms of inflammation, acting side-by-side with other suppressor factors generated upon ingestion of apoptotic cells.


Asunto(s)
Calgranulina B/inmunología , Macrófagos Peritoneales/inmunología , Neutrófilos/inmunología , Fagocitosis , Animales , Apoptosis/inmunología , Células Cultivadas , Técnicas de Cocultivo , Regulación hacia Abajo , Inflamación/inmunología , Ratones
14.
Biochim Biophys Acta ; 1801(4): 430-7, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20005974

RESUMEN

The aim of this study was to determine the apoptotic pathways and mechanisms involved in electronegative LDL [LDL(-)]-induced apoptosis in RAW 264.7 macrophages and the role of Nrf2 in this process. Incubation of RAW 264.7 macrophages with LDL(-) for 24 h resulted in dose-dependent cell death. Activated caspases were shown to be involved in the apoptosis induced by LDL(-); incubation with the broad caspase inhibitor z-VAD prevented apoptosis in LDL(-)-treated cells. CD95 (Fas), CD95 ligand (FasL), CD36 and the tumor necrosis factor (TNF) ligand Tnfsf10 were overexpressed in LDL(-)-treated cells. However, Bax, Bcl-2 and Mcl-1 protein levels remained unchanged after LDL(-) treatment. LDL(-) promoted hyperpolarization of the mitochondrial membrane, elevated reactive oxygen species (ROS) production and translocation of Nrf2 to the nucleus, a process absent in cells treated with native LDL. Elicited peritoneal macrophages from Nrf2-deficient mice exhibited an elevated apoptotic response after challenge with LDL(-), together with an increase in the production of ROS in the absence of alterations in CD36 expression. These results provide evidence that CD36 expression induced by LDL(-) is Nrf2-dependent. Also, it was demonstrated that Nrf2 acts as a compensatory mechanism of LDL(-)-induced apoptosis in macrophages.


Asunto(s)
Apoptosis , Lipoproteínas LDL/metabolismo , Macrófagos Peritoneales/patología , Factor 2 Relacionado con NF-E2/fisiología , Animales , Biomarcadores/metabolismo , Western Blotting , Antígenos CD36/genética , Antígenos CD36/metabolismo , Proteína Ligando Fas/genética , Proteína Ligando Fas/metabolismo , Femenino , Técnica del Anticuerpo Fluorescente , Perfilación de la Expresión Génica , Humanos , Macrófagos Peritoneales/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Análisis de Secuencia por Matrices de Oligonucleótidos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
15.
Braz. j. med. biol. res ; 41(12): 1086-1092, Dec. 2008. ilus, graf
Artículo en Inglés | LILACS | ID: lil-502158

RESUMEN

In order to determine the effect of antibodies against electronegative low-density lipoprotein LDL(-) on atherogenesis, five groups of LDL low receptor-deficient (LDLr-/-) mice (6 per group) were immunized with the following antibodies (100 µg each): mouse anti-LDL(-) monoclonal IgG2b, rabbit anti-LDL(-) polyclonal IgG or its Fab fragments and mouse irrelevant monoclonal IgG and non-immunized controls. Antibodies were administered intravenously one week before starting the hypercholesterolemic diet (1.25 percent cholesterol) and then every week for 21 days. The passive immunization with anti-LDL(-) monoclonal IgG2b, polyclonal antibody and its derived Fab significantly reduced the cross-sectional area of atherosclerotic lesions at the aortic root of LDLr-/- mice (28.8 ± 9.7, 67.3 ± 17.02, 56.9 ± 8.02 µm² (mean ± SD), respectively) compared to control (124.9 ± 13.2 µm²). Vascular cell adhesion molecule-1 protein expression, quantified by the KS300 image-analyzing software, on endothelium and the number of macrophages in the intima was also decreased in aortas of mice treated with anti-LDL(-) monoclonal antibody (3.5 ± 0.70 per field x 10) compared to controls (21.5 ± 3.5 per field x 10). Furthermore, immunization with the monoclonal antibody decreased the concentration of LDL(-) in blood plasma (immunized: 1.0 ± 1.4; control: 20.5 ± 3.5 RLU), the amount of cholesterol oxides in plasma (immunized: 4.7 ± 2.7; control: 15.0 ± 2.0 pg COx/mg cholesterol) and liver (immunized: 2.3 ± 1.5; control: 30.0 ± 26.0 pg COx/mg cholesterol), and the hepatic content of lipid hydroperoxides (immunized: 0.30 ± 0.020; control: 0.38 ± 0.15 ng/mg protein). In conclusion, antibodies against electronegative LDL administered intravenously may play a protective role in atherosclerosis.


Asunto(s)
Animales , Femenino , Ratones , Conejos , Anticuerpos Monoclonales/administración & dosificación , Aterosclerosis/terapia , Inmunización Pasiva/métodos , Inmunoglobulina G/administración & dosificación , Lipoproteínas LDL/administración & dosificación , Receptores de LDL/inmunología , Anticuerpos Monoclonales/inmunología , Aterosclerosis/inmunología , Aterosclerosis/metabolismo , Inmunohistoquímica , Fragmentos Fab de Inmunoglobulinas/administración & dosificación , Fragmentos Fab de Inmunoglobulinas/inmunología , Inmunoglobulina G/inmunología , Peroxidación de Lípido/inmunología , Lipoproteínas LDL/inmunología , Receptores de LDL/metabolismo , Molécula 1 de Adhesión Celular Vascular/inmunología
16.
Nephron Clin Pract ; 108(4): c298-304, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18434752

RESUMEN

BACKGROUND: Oxidative modification of low-density lipoprotein (LDL) has been demonstrated in patients with end-stage renal disease, where it is associated with oxidative stress and plays a key role in the pathogenesis of atherosclerosis. In this context, the generation of minimally oxidized LDL, also called electronegative LDL [LDL(-)], has been associated with active disease, and is a detectable sign of atherogenic tendencies. The purpose of this study was to evaluate serum LDL(-) levels and anti-LDL(-) IgG autoantibodies in end-stage renal disease patients on dialysis, comparing patients on hemodialysis (HD), peritoneal dialysis (PD) and a control group. In addition, the serum lipid profile, nutritional status, biochemical data and parameters of mineral metabolism were also evaluated. METHODS: The serum levels of LDL(-) and anti-LDL(-) IgG autoantibodies were measured in 25 patients undergoing HD and 11 patients undergoing PD at the Centro Integrado de Nefrologia, Rio de Janeiro, Brazil. Ten healthy subjects served as a control group. Serum levels of albumin, total cholesterol, triglycerides and lipoproteins were measured. Calculations of subjects' body mass index and measurements of waist circumference, triceps skin fold and arm muscle area were performed. Measurements of hematocrit, serum blood urea nitrogen, creatinine, parathyroid hormone, phosphorus and calcium were taken. RESULTS: Levels of LDL(-) were higher in HD patients (575.6 +/- 233.1 microg/ml) as compared to PD patients (223.4 +/- 117.5 microg/ml, p < 0.05), which in turn were higher than in the control group (54.9 +/- 33.3 mug/ml, p < 0.01). The anti-LDL(-) IgG autoantibodies were increased in controls (0.36 +/- 0.09 microg/ml) as compared to PD (0.28 +/- 0.12 microg/ml, p < 0.001) and HD patients (0.2 +/- 0.1 microg/ml, p < 0.001). The mean values of total cholesterol and LDL were considered high in the PD group, whereas the mean triceps skin fold was significantly lower in the HD group. CONCLUSION: Levels of LDL(-) are higher in renal patients on dialysis than in normal individuals, and are reciprocally related to IgG autoantibodies. LDL(-) may be a useful marker of oxidative stress, and this study suggests that HD patients are more susceptible to cardiovascular risk due to this condition. Moreover, autoantibodies reactive to LDL(-) may have protective effects in chronic kidney disease.


Asunto(s)
Autoanticuerpos/sangre , Inmunoglobulina G/sangre , Fallo Renal Crónico/sangre , Fallo Renal Crónico/terapia , Lipoproteínas LDL/sangre , Diálisis Peritoneal , Diálisis Renal , Adulto , Análisis de Varianza , Biomarcadores/sangre , Pesos y Medidas Corporales , Colesterol/sangre , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Fallo Renal Crónico/inmunología , Lipoproteínas LDL/inmunología , Lipoproteínas LDL/metabolismo , Masculino , Persona de Mediana Edad , Estado Nutricional , Estadísticas no Paramétricas
17.
Braz J Med Biol Res ; 41(12): 1086-92, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19148370

RESUMEN

In order to determine the effect of antibodies against electronegative low-density lipoprotein LDL(-) on atherogenesis, five groups of LDL low receptor-deficient (LDLr-/-) mice (6 per group) were immunized with the following antibodies (100 microg each): mouse anti-LDL(-) monoclonal IgG2b, rabbit anti-LDL(-) polyclonal IgG or its Fab fragments and mouse irrelevant monoclonal IgG and non-immunized controls. Antibodies were administered intravenously one week before starting the hypercholesterolemic diet (1.25% cholesterol) and then every week for 21 days. The passive immunization with anti-LDL(-) monoclonal IgG2b, polyclonal antibody and its derived Fab significantly reduced the cross-sectional area of atherosclerotic lesions at the aortic root of LDLr-/- mice (28.8 +/- 9.7, 67.3 +/- 17.02, 56.9 +/- 8.02 microm(2) (mean +/- SD), respectively) compared to control (124.9 +/- 13.2 microm(2)). Vascular cell adhesion molecule-1 protein expression, quantified by the KS300 image-analyzing software, on endothelium and the number of macrophages in the intima was also decreased in aortas of mice treated with anti-LDL(-) monoclonal antibody (3.5 +/- 0.70 per field x 10) compared to controls (21.5 +/- 3.5 per field x 10). Furthermore, immunization with the monoclonal antibody decreased the concentration of LDL(-) in blood plasma (immunized: 1.0 +/- 1.4; control: 20.5 +/- 3.5 RLU), the amount of cholesterol oxides in plasma (immunized: 4.7 +/- 2.7; control: 15.0 +/- 2.0 pg COx/mg cholesterol) and liver (immunized: 2.3 +/- 1.5; control: 30.0 +/- 26.0 pg COx/mg cholesterol), and the hepatic content of lipid hydroperoxides (immunized: 0.30 +/- 0.020; control: 0.38 +/- 0.15 ng/mg protein). In conclusion, antibodies against electronegative LDL administered intravenously may play a protective role in atherosclerosis.


Asunto(s)
Anticuerpos Monoclonales/administración & dosificación , Aterosclerosis/terapia , Inmunización Pasiva/métodos , Inmunoglobulina G/administración & dosificación , Lipoproteínas LDL/administración & dosificación , Receptores de LDL/inmunología , Animales , Anticuerpos Monoclonales/inmunología , Aterosclerosis/inmunología , Aterosclerosis/metabolismo , Femenino , Fragmentos Fab de Inmunoglobulinas/administración & dosificación , Fragmentos Fab de Inmunoglobulinas/inmunología , Inmunoglobulina G/inmunología , Inmunohistoquímica , Peroxidación de Lípido/inmunología , Lipoproteínas LDL/inmunología , Ratones , Ratones Endogámicos C57BL , Conejos , Receptores de LDL/metabolismo , Molécula 1 de Adhesión Celular Vascular/inmunología
18.
Br J Cancer ; 96(7): 1047-51, 2007 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-17353924

RESUMEN

To investigate the role of gefitinib in patients with high-grade gliomas (HGGs), a phase II trial (1839IL/0116) was conducted in patients with disease recurrence following surgery plus radiotherapy and first-line chemotherapy. Adult patients with histologically confirmed recurrent HGGs following surgery, radiotherapy and first-line chemotherapy, were considered eligible. Patients were treated with gefitinib (250 mg day(-1)) continuously until disease progression. The primary end point was progression-free survival at 6 months progression-free survival at 6 months (PFS-6). Tissue biomarkers (epidermal growth factor receptor (EGFR) gene status and expression, phosphorylated Akt (p-Akt) expression) were assessed. Twenty-eight patients (median age, 55 years; median ECOG performance status, 1) were enrolled; all were evaluable for drug activity and safety. Sixteen patients had glioblastoma, three patients had anaplastic oligodendrogliomas and nine patients had anaplastic astrocytoma. Five patients (17.9%, 95% CI 6.1-36.9%) showed disease stabilisation. The overall median time to progression was 8.4 (range 2-104+) weeks and PFS-6 was 14.3% (95% CI 4.0-32.7%). The median overall survival was 24.6 weeks (range 4-104+). No grade 3-4 gefitinib-related toxicity was found. Gefitinib showed limited activity in patients affected by HGGs. Epidermal growth factor receptor expression or gene status, and p-Akt expression do not seem to predict activity of this drug.


Asunto(s)
Antineoplásicos/uso terapéutico , Neoplasias Encefálicas/tratamiento farmacológico , Glioma/tratamiento farmacológico , Recurrencia Local de Neoplasia/tratamiento farmacológico , Quinazolinas/uso terapéutico , Adulto , Anciano , Astrocitoma/tratamiento farmacológico , Astrocitoma/secundario , Neoplasias Encefálicas/secundario , Supervivencia sin Enfermedad , Receptores ErbB/antagonistas & inhibidores , Femenino , Gefitinib , Glioma/patología , Humanos , Masculino , Dosis Máxima Tolerada , Persona de Mediana Edad , Recurrencia Local de Neoplasia/patología , Estadificación de Neoplasias , Oligodendroglioma/tratamiento farmacológico , Oligodendroglioma/secundario , Tasa de Supervivencia , Resultado del Tratamiento
19.
Med Phys ; 34(12): 4901-10, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18196815

RESUMEN

A computer-aided detection (CAD) system for the selection of lung nodules in computer tomography (CT) images is presented. The system is based on region growing (RG) algorithms and a new active contour model (ACM), implementing a local convex hull, able to draw the correct contour of the lung parenchyma and to include the pleural nodules. The CAD consists of three steps: (1) the lung parenchymal volume is segmented by means of a RG algorithm; the pleural nodules are included through the new ACM technique; (2) a RG algorithm is iteratively applied to the previously segmented volume in order to detect the candidate nodules; (3) a double-threshold cut and a neural network are applied to reduce the false positives (FPs). After having set the parameters on a clinical CT, the system works on whole scans, without the need for any manual selection. The CT database was recorded at the Pisa center of the ITALUNG-CT trial, the first Italian randomized controlled trial for the screening of the lung cancer. The detection rate of the system is 88.5% with 6.6 FPs/CT on 15 CT scans (about 4700 sectional images) with 26 nodules: 15 internal and 11 pleural. A reduction to 2.47 FPs/CT is achieved at 80% efficiency.


Asunto(s)
Diagnóstico por Computador/métodos , Pulmón/diagnóstico por imagen , Pulmón/patología , Modelos Biológicos , Dosis de Radiación , Tomografía Computarizada por Rayos X , Algoritmos , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/diagnóstico por imagen , Redes Neurales de la Computación , Curva ROC
20.
G Ital Med Lav Ergon ; 29(3 Suppl): 256-8, 2007.
Artículo en Italiano | MEDLINE | ID: mdl-18409673

RESUMEN

Thirty-two voluntary subjects were selected, not suffering either from any degenerative ophthalmic diseases or refraction and ocular motility alterations. Each subject underwent close visual task experimental sessions (e.g. PC usage), under monitored experimental conditions. Aim of the study is the assessment of working efficiency effects caused by lighting conditions characterized by "according to law" illuminations, yet in presence of high or low luminance ratios in the occupational visual field". An analysis of the data showed that high luminance ratios conditions show a decrease of the performance (decrease overall efficiency, increase in the number of errors and time of execution), which where not detected with low luminance ratios conditions. Asthenopia did not show clear differences, possibly due to the effects of the intense near work which was present in both the experimental sessions.


Asunto(s)
Iluminación/normas , Análisis y Desempeño de Tareas , Lugar de Trabajo , Adolescente , Adulto , Femenino , Humanos , Masculino
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