| 1. |
- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 2. |
- Benetti, M., et al.
(författare)
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POLYSILICON MESOSCOPIC WIRES COATED BY Pd AS H(2) SENSORS
- 2009
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Ingår i: PROCEEDINGS OF THE 13TH ITALIAN CONFERENCE ON SENSORS AND MICROSYSTEMS. - SINGAPORE : WORLD SCIENTIFIC PUBL CO PTE LTD. ; , s. 161-165
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Konferensbidrag (refereegranskat)abstract
- In this work a novel monocrystalline silicon nanowires array has been investigated and presented as hydrogen sensor, designed and fabricated by employing high resolution microfabrication techniques and featuring a high surface/volume ratio. The nanowires arrays makes up the channel of a MOS system, palladium-silicon dioxide-silicon. Several devices have been fabricated by using a SOI (Silicon On Insulator) substrate, Source and Drain have been geometrically patterned by optical lithography and Boron p-doped. Electron Beam Litography (EBL) defined the MOS channel made up of a nanowires array of different length and width in different transistors. The pads of Source and Drain have been manufactured with an aluminium film deposition. The Gate has been fabricated with a grown silicon oxide layer (17.4 nm) and Palladium has been used as gate contact. Polarizing and exposing the device to H(2)/N(2) cycles at different concentrations some preliminary measurements have been successfully conducted.
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| 3. |
- Di, Natale C., et al.
(författare)
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An experimental biomimetic platform for artificial olfaction
- 2008
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:9
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Tidskriftsartikel (refereegranskat)abstract
- Artificial olfactory systems have been studied for the last two decades mainly from the point of view of the features of olfactory neuron receptor fields. Other fundamental olfaction properties have only been episodically considered in artificial systems. As a result, current artificial olfactory systems are mostly intended as instruments and are of poor benefit for biologists who may need tools to model and test olfactory models. Herewith, we show how a simple experimental approach can be used to account for several phenomena observed in olfaction. An artificial epithelium is formed as a disordered distributed layer of broadly selective color indicators dispersed in a transparent polymer layer. The whole epithelium is probed with colored light, imaged with a digital camera and the olfactory response upon exposure to an odor is the change of the multispectral image. The pixels are treated as olfactory receptor neurons, whose optical properties are used to build a convergence classifier into a number of mathematically defined artificial glomeruli. A non-homogenous exposure of the test structure to the odours gives rise to a time and spatial dependence of the response of the different glomeruli strikingly similar to patterns observed in the olfactory bulb. The model seems to mimick both the formation of glomeruli, the zonal nature of olfactory epithelium, and the spatio-temporal signal patterns at the glomeruli level. This platform is able to provide a readily available test vehicle for chemists developing optical indicators for chemical sensing purposes and for biologists to test models of olfactory system organization. © 2008 Di Natale et al.
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| 4. |
- Di Natale, C, et al.
(författare)
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An artificial olfaction system based on the optical imaging of a large array of chemical reporters
- 2009
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Ingår i: SENSORS AND ACTUATORS B-CHEMICAL. - : Elsevier BV. - 0925-4005. ; 142:2, s. 412-417
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Tidskriftsartikel (refereegranskat)abstract
- Electronic noses are object of research since more than two decades; nonetheless. the analogies between natural and olfaction systems are still limited to the selectivity properties of the receptors. The implementation of more sophisticated features such as the large number of receptors and the glomeruli layer have been hampered by technical difficulties related to the management of a large number of contemporaneous signals. As demonstrated in the past, optical imaging is a read-out technique for sensors development that can provide large sensor arrays. In this paper an artificial olfaction system based on the imaging of a continuous layer of chemical indicators is illustrated. The system incorporates an array of thousands of sensors, corresponding to the pixels of the image. The choice of Computer Screen Photoassisted Technology as a platform for optical interrogation of the sensing layer allows for the definition of a strategy for an automatic definition of a glomeruli layer based on the classification of the optical fingerprints of the image pixels. Chemical indicators were dissolved into a polymeric matrix providing the further property of odor diffusion mimicking the functions of the olfactory mucosa. The system has been tested in a simple experiment and data have been treated applying a lateral inhibition to the glomeruli layer resulting in a dynamic pattern resembling that observed in natural olfaction.
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| 5. |
- Di Natale, Corrado, et al.
(författare)
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Investigation of the selectivity properties of metalloporphyrines self-assembled-monolayers on QMB and FET transducers
- 2006
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Ingår i: Proc Eurosensors XX.
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Konferensbidrag (refereegranskat)abstract
- Progresses of synthetic chemistry methodologies have allowed the preparation of a great variety of artificial receptors that are particularly appealing for chemical sensor development. In this paper, we investigate and compare the properties of gas sensors based on two types of devices, quartz microbalances (QMBs) and field effect transistors (FETs), which give the means to exploit the molecular recognition events occurring in non-conductive sensing layers formed by a thiol-modified cobalt tetraphenylporphyrin (CoTPPSH). Since QMB is sensitive to mass and FET is sensitive to electric dipoles, the resulting sensors are expected to exhibit different sensitivities and selectivities, although both based on the same sensing layer. In particular we show that the high sensitivity of CoTPPSH-coated FETs towards CO and NO is a consequence of the significant CoTPPSH electric dipole change after the gas coordination to the metal centre.
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| 6. |
- Gatto, E., et al.
(författare)
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Polychromatic fingerprinting of excitation emission matrices
- 2008
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 14:20, s. 6057-6060
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Tidskriftsartikel (refereegranskat)abstract
- The ability of a ubiquitous polychromatic excitation to support the fingerprinting of the Excitation Emission Matrices (EEM) of fluorescent indicators was reported. Solutions of fluorescent molecules, with concentration of 2µM for the absorption and 10µM for the emission measurements were prepared. Spectroscopic grade THF and distilled water passed through Milli-Q purification system were used as solvents. EEM measurements were carried out on a spectrofluorimeter, operating in the 390-700 nm detection range, with excitations at 20 nm intervals within the same range. During the measurement, the screen displayed a sequence of 50 colors and for every color, the transmission and emission spectrum of both the reference and the sample were recorded. Illuminating colors in the red region are not able to excite fluorescence and this can be seen in the spectra for red light.
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| 7. |
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| 8. |
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| 9. |
- Martinelle, E, et al.
(författare)
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FET Transduction of Electric Dipole Changes in Organic Layers
- 2007
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Ingår i: TRANSDUCERS 2007 - 2007 International Solid-State Sensors, Actuators and Microsystems Conference. - : IEEE. - 1424408423 - 1424408415 ; , s. 1895-1898
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Konferensbidrag (refereegranskat)abstract
- Modern chemistry makes possibile the production of artificial receptors endowed with interaction sites specific towards selected analytes. To fabricate chemical sensors a transducer able to preserve the selectivity of such sensing layers is requested. We demonstrate the Field Effect Transistors (FET) coated by metalloporphyrins emphasizes the coordination of analytes with the sensing molecules with respect to the weakest forces that tend to cancel the selectivity. Molecular simulations show that coordination of gases such as carbon monoxide and nitric oxide greatly change the porphyrin electric dipole both in magnitude and direction inducing a large FET signal shift.
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| 10. |
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