Biomedical subjects

P Maioli

Publications and source records attributed to P Maioli.

9 recordsLinked to original sources

PubMed2005

Nondestructive Rydberg atom counting with mesoscopic fields in a cavity.

We present an efficient, state-selective, nondemolition atom-counting procedure based on the dispersive interaction of a sample of circular Rydberg atoms with a mesoscopic field contained in a high-quality superconducting cavity. The state-dependent atomic index of refraction, proportional to the atom number, shifts the classical field phase. A homodyne procedure translates the information from the phase to the intensity. The final field intensity is readout by a mesoscopic atomic sample. This method opens promising routes for quantum information processing and nonclassical state generation with Rydberg atoms.

Journal Article↗

PubMed2005

Rabi oscillations revival induced by time reversal: a test of mesoscopic quantum coherence.

Using an echo technique proposed by Morigi et al., we have time-reversed the atom-field interaction in a cavity quantum electrodynamics experiment. The collapse of the atomic Rabi oscillation in a coherent field is reversed, resulting in an induced revival signal. The amplitude of this "echo" is sensitive to nonunitary decoherence processes. Its observation demonstrates the existence of a mesoscopic quantum superposition of field states in the cavity between the collapse and the revival times.

Journal Article↗

PubMed2003

Entanglement of a mesoscopic field with an atom induced by photon graininess in a cavity.

We observe that a mesoscopic field made of several tens of microwave photons exhibits quantum features when interacting with a single Rydberg atom in a high-Q cavity. The field is split into two components whose phases differ by an angle inversely proportional to the square root of the average photon number. The field and the atomic dipole are phase entangled. These manifestations of photon graininess vanish at the classical limit. This experiment opens the way to studies of large quantum state superpositions at the quantum-classical boundary.

Journal Article↗

PubMed2002

Direct measurement of the Wigner function of a one-photon Fock state in a cavity.

We have measured the complete Wigner function W of the vacuum and of a single-photon state for a field stored in a high-Q cavity. This experiment implements the direct Lutterbach and Davidovich method [L. G. Lutterbach and L. Davidovich, Phys. Rev. Lett. 78, 2547 (1997)]] and is based on the dispersive interaction of a single circular Rydberg atom with the cavity field. The nonclassical nature of the single-photon field is exhibited by a region of negative W values. Extensions to other nonclassical cavity field states are discussed.

Journal Article↗

PubMed2002

Generating and probing a two-photon fock state with a single atom in a cavity.

A two-photon Fock state is prepared in a cavity sustaining a "source mode" and a "target mode," with a single circular Rydberg atom. In a third-order Raman process, the atom emits a photon in the target while scattering one photon from the source into the target. The final two-photon state is probed by measuring by Ramsey interferometry the cavity light shifts induced by the target field on the same atom. Extensions to other multiphoton processes and to a new type of micromaser are briefly discussed.

Journal Article↗

PubMed2001

Coherent control of an atomic collision in a cavity.

Following a recent proposal by S. B. Zheng and G. C. Guo [Phys. Rev. Lett. 85, 2392 (2000)], we report an experiment in which two Rydberg atoms crossing a nonresonant cavity are entangled by coherent energy exchange. The process, mediated by the virtual emission and absorption of a microwave photon, is characterized by a collision mixing angle 4 orders of magnitude larger than for atoms colliding in free space with the same impact parameter. The final entangled state is controlled by adjusting the atom-cavity detuning. This procedure, essentially insensitive to thermal fields and to photon decay, opens promising perspectives for complex entanglement manipulations.

Journal Article↗

PubMed1999

Prognostic and predictive value of intratumoral microvessels density in operable non-small-cell lung cancer.

Experimental evidence suggests that tumor growth and progression depend on angiogenesis. In a retrospective study we evaluated the relationship between tumor angiogenesis and survival in patients with NSCLC treated with potentially curative surgery between 1992 and 1997. The study population consisted of 76 patients. An anti-CD34 monoclonal antibody was used to measure angiogenesis in tumor samples. Angiogenesis was quantified in terms of microvessel count (MVC): in each sample the three most intense regions of neovascularization were identified under low microscopic power. A x250 field in each of the three areas was then counted and the highest count of the three fields was recorded. Disease free (DFS) and overall survival (OS) during follow up were evaluated. Gender, age, stage, histologic type and KI-67 were the other factors considered for analysis. The median MVC in our series was 41.5. Among the clinicopathologic parameters examined the microvessel count was the only one to show a significant association with disease free survival in univariate analysis (P = 0.04). MVC value is a new indicator of tumor aggressiveness in patients with NSCLC who underwent potentially curative surgery and should be taken into consideration in selecting patients for adjuvant treatment.

Aged↗

PubMed1996

Intralaboratory reproducibility of cervical cytology diagnoses in the external quality assurance scheme of the Emilia-Romagna region of Italy.

In an external quality assurance (EQA) scheme, 110 selected cervical smears were independently reported by seven cytology laboratories using the 1988 Bethesda System. In one of these, a random sample of 60 study smears was independently classified by five cytologists before undergoing joint examination according to EQA protocol. Internal agreement (i.e., among these cytologists) was compared with external agreement (between these cytologists and the other six laboratories) and with interlaboratory agreement (among these laboratories). The kappa value for internal agreement on sample adequacy (0.57) was considerably greater than those for external (0.16) and interlaboratory agreement (0.10). For interpretation of epithelial abnormalities, internal kappa was excellent (0.80) but not substantially greater compared with external kappa (0.66) and interlaboratory kappa (0.70). Calculation of class-specific kappa values revealed (a) that superiority of internal agreement on sample adequacy was restricted to the notations of "less than optimal" and of "satisfactory," and (b) that internal increase in agreement on cytologic abnormalities was substantial for the diagnosis of "atypical cells of undetermined significance."

Cervix Uteri↗

PubMedDate not supplied

Is it possible to define a better ASCUS class in cervicovaginal screening? A review of 187 cases.

OBJECTIVE: To try to better define the cytologic diagnosis of atypical squamous cells of undetermined significance (ASCUS) in a cervical screening protocol. STUDY DESIGN: Smears from 187 patients with cytologic diagnoses of ASCUS and histologic or two years' cytologic/colposcopic follow-up were reviewed. When an ASCUS diagnosis was confirmed, it was done strictly on the basis of the morphologic criteria recommended by the Regione Emilia Romagna Screening Protocol in 1997, trying also to subclassify ASCUS into favor reactive or favor neoplasia. RESULTS: Seventy ASCUS cases were negative (37.4%). Three cases (1.6%) were low grade squamous intraepithelial lesion, and seven (3.8%) were high grade squamous intraepithelial lesion. One hundred seven ASCUS cases (57.2%) were confirmed. Among the 70 negative cases, 36 (51.4%) had reactive changes on biopsy, 30 (42.9%) koilocytosis, 3 cervical intraepithelial neoplasia (CIN 1) and one CIN not otherwise specified (5.7% total). CONCLUSION: Reclassification of ASCUS cases using tighter criteria reduced them to a rate of 57.2% but missed 30 patients with histologic diagnoses of koilocytosis and 4 with histologic diagnoses of CIN.

Biopsy↗