| 1. |
- Akola, J., et al.
(författare)
-
Thiolate-Protected Au-25 Superatoms as Building Blocks: Dimers and Crystals
- 2010
-
Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 114:38, s. 15986-15994
-
Tidskriftsartikel (refereegranskat)abstract
- A particularly stable thiolate-protected gold nanocluster, Au-25(SR)(18), was structurally characterized from X-ray crystallography in 2008, and concomitantly its electronic and optical properties were analyzed via density functional theory. The robust geometry and a well-understood electronic structure of this cluster motivate explorations of properties of extended systems made out of Au-25(SR)(18) building blocks. As a first step in this direction, we analyze here structural, vibrational, electronic, and optical properties of the Au-25 cluster anion as it was observed in the crystalline environment and predict properties of cluster dimers, where the Au-25 units are linked together. via an aromatic dithiolate linker. We show that properties of each Au-25 unit of the dimer can be quite independently modified from the other by doping with a nonmagnetic (Pd) or magnetic (Mn) metal atom. We anticipate that material systems with interesting properties could be made from these building blocks, provided that a suitable chemistry for their controlled linking can be found.
|
|
| 2. |
- Babusci, D., et al.
(författare)
-
A new limit on the CP violating decay K-S -> 3 pi(0) with the KLOE experiment
- 2013
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 723:1-3, s. 54-60
-
Tidskriftsartikel (refereegranskat)abstract
- We have carried out a new direct search for the CP violating decay K-S -> 3 pi(0) with 1.7 fb(-1) of e(+)e(-) collisions collected by the KLOE detector at the Phi-factory DA Phi NE. We have searched for this decay in a sample of about 5.9 x 10(8) KSKL events tagging the K-S by means of the K-L interaction in the calorimeter and requiring six prompt photons. With respect to our previous search, the analysis has been improved by increasing of a factor four the tagged sample and by a more effective background rejection of fake K-S tags and spurious clusters. We find no candidates in data and simulated background samples, while we expect 0.12 standard model events. Normalizing to the number of K-S -> 2 pi(0) events in the same sample, we set the upper limit on BR(K-S -> 3 pi(0)) <= 2.6 x 10(-8) at 90% C.L., five times lower than the previous limit. We also set the upper limit on the eta(000) parameter, vertical bar eta(000)vertical bar <= 0.0088 at 90% C.L., improving by a factor two the latest direct measurement. (c) 2013 Elsevier B.V. All rights reserved.
|
|
| 3. |
- Babusci, D., et al.
(författare)
-
Search for light vector boson production in e(+)e(-) -> mu(+)mu(-)gamma interactions with the KLOE experiment
- 2014
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 736, s. 459-464
-
Tidskriftsartikel (refereegranskat)abstract
- We have searched for a light vector boson U, the possible carrier of a "dark force", with the KLOE detector at the DA Phi NE e(+)e(-) collider, motivated by astrophysical evidence for the presence of dark matter in the Universe. Using e(+)e(-) collisions collected with an integrated luminosity of 239.3 pb(-1), we look for a dimuon mass peak in the reaction e(+)e(-) -> mu(+)mu(-)gamma, corresponding to the decay U -> mu(+)mu(-). We find no evidence for a U vector boson signal. We set a 90% CL upper limit for the mixing parameter squared between the photon and the U boson of 1.6 x 10(-5) to 8.6 x 10(-7) for the mass region 520 < m(U) < 980 MeV.
|
|
| 4. |
- Babusci, D., et al.
(författare)
-
Test of CPT and Lorentz symmetry in entangled neutral kaons with the KLOE experiment
- 2014
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 730, s. 89-94
-
Tidskriftsartikel (refereegranskat)abstract
- Neutral kaon pairs produced in phi decays in anti-symmetric entangled state can be exploited to search for violation of CPT symmetry and Lorentz invariance. We present an analysis of the CP-violating process phi -> KSKL -> pi(+)pi(-)pi(+)pi(-) based on 1.7 fb(-1) of data collected by the KLOE experiment at the Frascati phi-factory DA Phi NE. The data are used to perform a Measurement of the CPT-violating parameters Delta a(mu) for neutral kaons in the context of the Standard Model Extension framework. The parameters measured in the reference frame of the fixed stars are: Delta a(0) = (-6.0 +/- 7.7(stat)+/- 3.1(syst)) X 10(-18) GeV, Delta a(x) = (0.9 +/- 1.5(stat)+/- 0.6(syst)) X 10(-18) GeV, Delta a(y) = (-2.0 +/- 1.5(stat)+/- 0.5(syst)) X 10(-18) GeV, Delta a(z) = (3.1 +/- 1.7(stat)+/- 0.5(syst)) X 10(-18) GeV. These are presently the most precise measurements in the quark sector of the Standard Model Extension. (C) 2014 The Authors. Published by Elsevier B.V.
|
|
| 5. |
- Jackowski, G, et al.
(författare)
-
Identification of Lhcb1/Lhcb2/Lhcb3 heterotrimers of the main light-harvesting chlorophyll a/b-protein complex of Photosystem II (LHC II)
- 2001
-
Ingår i: Biochimica et Biophysica Acta - Bioenergetics. - 0005-2728 .- 1879-2650. ; 1504:2-3, s. 340-345
-
Tidskriftsartikel (refereegranskat)abstract
- Using non-denaturing isoelectric focusing in polyacrylamide vertical slab gel, we have purified to homogeneity three trimeric subcomplexes of LHC II from Arabidopsis thylakoid membranes. The polypeptide composition of the subcomplexes were studied by immunoblotting. Our results indicate the existence in vivo of LHC II heterotrimers containing Lhcb1, Lhcb2 and Lhcb3 gene products. (C) 2001 Elsevier Science B.V. All rights reserved.
|
|
| 6. |
- Kacprzak, K. A., et al.
(författare)
-
Theoretical Characterization of Cyclic Thiolated Copper, Silver, and Gold Clusters
- 2010
-
Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 114:32, s. 13571-13576
-
Tidskriftsartikel (refereegranskat)abstract
- Density functional theory calculations are used to study structural, electronic, and vibrational properties of cyclic (MeSM)(x) clusters where MeS is methylthiolate and M is copper, silver, or gold. The clusters show a flexible bond motif where monocyclic rings, catenanes, and helix structures compete in energy. In the investigated series, the copper-sulfur bond is found to be the strongest metal-sulfur bond, followed by gold-sulfur and silver-sulfur. Analysis of the bond character reveals that Cu-S is the most polar bond, whereas Au-S is mainly of covalent type. Vibrational analysis shows characteristic metal-sulfur stretch vibrations for each noble metal.
|
|
| 7. |
- Sawosz, P., et al.
(författare)
-
Human skull translucency : post mortem studies
- 2016
-
Ingår i: Biomedical Optics Express. - 2156-7085. ; 7:12, s. 5010-5020
-
Tidskriftsartikel (refereegranskat)abstract
- Measurements of optical translucency of human skulls were carried out. An incandescent light source and a CCD camera were used to measure the distribution of light transmitted through the skull in 10 subjects post-mortem. We noticed that intra-individual differences in optical translucency may be up to 100 times but inter-individual translucency differences across the skull reach 105 times. Based on the measurement results, a "theoretical" experiment was simulated. Monte-Carlo calculations were used in order to evaluate the influence of the differences in optical translucency of the skull on results of NIRS measurements. In these calculations a functional stimulation was done, in which the oxyhemoglobin and deoxyhemoglobin concentrations in the brain cortex change by 5 mu M and -5 mu M respectively. The maximal discrepancies between assumed hemoglobin concentration changes and hemoglobin concentration changes estimated with Monte-Carlo simulation may reach 50% depending of the translucency of the skull.
|
|
| 8. |
- Spinelli, L., et al.
(författare)
-
Determination of reference values for optical properties of liquid phantoms based on Intralipid and India ink
- 2014
-
Ingår i: Biomedical Optics Express. - : Optical Society of America. - 2156-7085. ; 5:7, s. 2037-2053
-
Tidskriftsartikel (refereegranskat)abstract
- A multi-center study has been set up to accurately characterize the optical properties of diffusive liquid phantoms based on Intralipid and India ink at near-infrared (NIR) wavelengths. Nine research laboratories from six countries adopting different measurement techniques, instrumental set-ups, and data analysis methods determined at their best the optical properties and relative uncertainties of diffusive dilutions prepared with common samples of the two compounds. By exploiting a suitable statistical model, comprehensive reference values at three NIR wavelengths for the intrinsic absorption coefficient of India ink and the intrinsic reduced scattering coefficient of Intralipid-20% were determined with an uncertainty of about 2% or better, depending on the wavelength considered, and 1%, respectively. Even if in this study we focused on particular batches of India ink and Intralipid, the reference values determined here represent a solid and useful starting point for preparing diffusive liquid phantoms with accurately defined optical properties. Furthermore, due to the ready availability, low cost, long-term stability and batch-to-batch reproducibility of these compounds, they provide a unique fundamental tool for the calibration and performance assessment of diffuse optical spectroscopy instrumentation intended to be used in laboratory or clinical environment. Finally, the collaborative work presented here demonstrates that the accuracy level attained in this work for optical properties of diffusive phantoms is reliable.
|
|
