Biomedical subjects
Publications and source records attributed to F Piacentini.
We demonstrate a method to reconstruct the joint photon statistics of two or more modes of radiation by using on/off photodetection performed at different quantum efficiencies. The two-mode case is discussed in detail, and experimental results are presented for the bipartite states obtained after a beam splitter fed by a single photon state or a thermal state.
Since its presentation by Mirizzi in 1931, the role of intraoperative cholangiography (ICHO) has been controversial and has become an argument even more disputed with the introduction of laparoscopic cholecystectomy (VLC) in 1988. The Authors reviewed their experience to determine the most appropriate use of ICHO during VLC on the basis of a retrospective analysis of cases of selective ICHO. From December 1991 to January 2001, 597 patients, 552 elective procedure and 45 emergency procedure, were reviewed. Of 552 patients 62 presented with at least one diagnostic criterion for symptomatic gallstone disease and were treated by means of ERCP completed with endoscopic sphincterectomy (ES) when a stone of the common bile duct was found, while the remaining 490 patients underwent VLC; a total of 10 ICHO were performed, two of which in the ERCP group and 8 in the VLC group. The 45 patients treated in emergency underwent VLC; in 43 cases ICHO was performed. Of all patients, there were 2 cases of common bile duct injuries (0.33%) and in both cases ICHO was not performed. A cholangiogram added 27 min to the average duration of surgery. On the basis of both the literature and Authors' experience, it can be stated that the routine use of ICHO is not useful to reduce bile duct injuries, while it significantly increases the cost of the surgical procedure due to the increase of average operative time. The use of ICHO seems to be effective to demonstrate clinically unsuspected choledocholitiasis, although, at present, the real clinical advantage deriving from the detection of these stones is not clear. The Authors conclude that further prospective, randomized studies are necessary to assess the precise role of ICHO with regard to VLC.
Recent results from BOOMERANG-98 and MAXIMA-1, taken together with COBE DMR, provide consistent and high signal-to-noise measurements of the cosmic microwave background power spectrum at spherical harmonic multipole bands over 2<l less similar to 800. Analysis of the combined data yields 68% (95%) confidence limits on the total density, Omega(tot) approximately 1.11+/-0.07 (+0.13)(-0.12), the baryon density, Omega(b)h(2) approximately 0.032(+0.005)(-0.004) (+0.009)(-0.008), and the scalar spectral tilt, n(s) approximately 1.01(+0.09)(-0.07) (+0.17)(-0.14). These data are consistent with inflationary initial conditions for structure formation. Taken together with other cosmological observations, they imply the existence of both nonbaryonic dark matter and dark energy in the Universe.
We describe a measurement of the angular power spectrum of anisotropies in the cosmic microwave background (CMB) at scales of 0&fdg;3 to 5 degrees from the North American test flight of the Boomerang experiment. Boomerang is a balloon-borne telescope with a bolometric receiver designed to map CMB anisotropies on a long-duration balloon flight. During a 6 hr test flight of a prototype system in 1997, we mapped more than 200 deg(2) at high Galactic latitudes in two bands centered at 90 and 150 GHz with a resolution of 26&arcmin; and 16&farcm;5 FWHM, respectively. Analysis of the maps gives a power spectrum with a peak at angular scales of 1 degrees with an amplitude 70 µK(CMB).
We use the angular power spectrum of the cosmic microwave background, measured during the North American test flight of the Boomerang experiment, to constrain the geometry of the universe. Within the class of cold dark matter models, we find that the overall fractional energy density of the universe Omega is constrained to be 0.85</=Omega</=1.25 at the 68% confidence level. Combined with the COBE measurement, the data on degree scales from the Microwave Anisotropy Telescope in Chile, and the high-redshift supernovae data, we obtain new constraints on the fractional matter density and the cosmological constant.
OBJECTIVE: A circadian rhythm of blood pressure has been demonstrated both in subjects who are physically active during the day and in those confined to bed. The study of the circadian rhythm of arterial flow and peripheral resistance, on the other hand, is limited to pioneer experiments. This paper is aimed at demonstrating that leg peripheral resistance has circadian fluctuations which are modulated by spinal neural traffic. METHODS: Eleven normal (able-bodied) human subjects and 11 patients with spinal transection due to spinal cord injury (SCI) were studied. They were confined to bed for 24 h. Blood pressure and heart rate were monitored every 15 min with an automatic device and leg flow with an automatic strain-gauge plethysmograph synchronised to the pressurometer. Peripheral resistance was calculated at the same intervals. RESULTS: In able-bodied subjects leg resistance was significantly higher during waking hours (when the sympathetic system is more activated) than during sleep, while in subjects with spinal cord injury no difference was detected between day-time and night-time. CONCLUSIONS: The circadian rhythm is controlled by adrenergic fibres transmitted via the spinal cord.
Fifty-six children with chronic asthma, 6 to 14 years of age, were studied to evaluate bronchoconstrictive airway responses after ingestion of varying doses of potassium bisulfite administered in one occasion in capsule and in another occasion in solution. With methacholine challenge before and after metabisulfite (MBS) provocation, the relationship of bronchoconstrictive responses and bronchial hyperreactivity was evaluated. Positive bronchoconstrictive responses were observed in only four children after the ingestion of a maximum dose of MBS in capsule and in two children after the ingestion of different doses of MBS solution. A high reactivity to methacholine challenge was present in all the reactive children. After MBS challenge, no additional changes in bronchial reactivity were observed either in the reactors or nonreactors.
The authors report about their first study of the detrusor activity modifications induced by electrical stimulation of the posterior tibial nerve in six patients with neurogenic bladder. The results suggest that this new application inhibit detrusor activity.
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We present a case of a girl with Poland's Syndrome (absence of pectoral muscle and syndactyly) associated with Moebius Syndrome. More abnormalities, especially visceral, may be associated with it and therefore the clinician must know and identify them as soon as possible. We underline the importance of a precocious correction of the hand's abnormalities in order to avoid changes in the corporal pattern otherwise not correctible later. A retard in surgical treatment will produce a failure like in our patient.