Search

Risk factors for Peyronie's disease (PD) are serum lipid abnormalities, hypertension and type 2 diabetes mellitus (T2DM). Oxidative stress and inflammation are key-players in the pathogenesis of arterial diseases, leading to insulin resistance (IR), which is a major determinant of non-alcoholic fatty liver disease (NAFLD). We studied the potential relationship between PD, IR, and NAFLD. Forty-nine male patients were enrolled, fulfilling the well-accepted diagnostic criteria of stable PD. Fifty male individuals without PD, well-matched for age and BMI, were selected as the control group. Comorbidities (T2DM and hypertension), as well as the lipid profile and the glucometabolic asset, were evaluated. The triglycerides/HDL ratio (TG/HDL-C ratio) with a cut-off of ≥3 and the triglycerides-glucose index (TyG) with an optimal cut-point of 8.5 were used for diagnosis of IR and NAFLD, respectively. NAFLD diagnosis was confirmed by the presence of bright liver at ultrasonography. Hypertension was found more frequently in PD patients than in no-PD subjects (P=0.017), independently of age (P=0.99). Both IR and NAFLD were significantly associated with the presence of PD in our population of men (P=0.043 and 0.0001, respectively), no matter how old (P=0.11 and 0.74, respectively). At logistic regression, NAFLD was the only predictor of the PD presence (p=0.021). The AUROC of TyG to predict PD was 0.7437 (sensitivity 67.35% and specificity 80%) with a percentage of correctly classified patients of 73.74%. Oxidative stress markers were significantly associated with NAFLD. Testosterone level was significantly low in the subjects with NAFLD in cross-sectional analyses. Both factors, i.e., oxidative stress and hypogonadism, are central to PD pathogenesis. In conclusion, NAFLD and IR are strongly associated with PD. The pathogenic link between these conditions and the underlying mechanisms are only hypothetical and thoroughly summarized in the discussion.

The photodegradative activity of titanium dioxide immobilized into a multilayered transparent fluoropolymeric matrix has been studied. The multilayered coating photocatalytic activity towards hydrosoluble organic pollutants was evaluated in clear as well as in highly turbid conditions obtained by dispersing barium sulfate microparticles in the polluted solution. Rhodamine B-base was chosen as reference organic pollutant

The problem of relativistic causality in the time-dependent three-body Casimir–Polder interaction energy between three atoms, initially in their bare ground-state, is discussed. It is shown that the non-locality of the spatial correlations of the electromagnetic field emitted by the atoms during their dynamical self-dressing may become manifest in the dynamical three-body Casimir–Polder interaction energy between the three atoms.

We consider three two-level atoms inside a one-dimensional cavity, interacting with the electromagnetic field in the rotating wave approximation (RWA), commonly used in the atom-radiation interaction. One of the three atoms is initially excited, and the other two are in their ground state. We numerically calculate the propagation of the field spontaneously emitted by the excited atom and scattered by the second atom, as well as the excitation probability of the second and third atom. The results obtained are analyzed from the point of view of relativistic causality in the atom-field interaction. We show that, when the RWA is used, relativistic causality is obtained only if the integrations over the field frequencies are extended to $-\infty$; on the contrary, noncausal tails remain even if the number of field modes is increased. This clearly shows the limit of the RWA in dealing with subtle problems such as relativistic causality in the atom-field interaction., Comment: 13 pages, 6 figures

The radiation diffused by a one-dimensional homonuclear molecular ion driven by a laser field is studied as a function of the time. When the photon energy is resonant with the energy gap between the ground and the first excited state, the electronic probability density is seen to undergo slow and deep oscillations between the two nuclei. Synchronous to such oscillations, deep modulations of the emitted power are observed. The period of oscillation is of the order of 10 optical cycles. Detection of the variation in the intensity of the emitted electromagnetic spectrum therefore brings information on the position of the electron in the molecule.

A canonical approach to self-dressing in classical electrodynamics is presented. A slowly moving, rigid charge distribution is assumed to be completely deprived of the transverse electric E⊥ at an initial time t1' and the development of this component of the field is studied for t > t1' by solving the coupled charge-field Hamilton equations of motion. The theory is specialized to charge distributions of spherical symmetry, and in particular the point-charge, the spherical shell of charge and the spherical volume of charge are considered. As for the dynamics of the charge, the radiation-reaction force during self-dressing is obtained and it is shown to be substantially different at short times from the familiar form obtained for fully dressed charges, although it reduces to the latter for times longer than the time taken by the light to traverse the charge. Finally the most prominent features of the solution of the charge equation of motion for short times are discussed. As for the field, an auxiliary field Ec is introduced which is related to E⊥ and which has the advantage of being easily calculable. It is shown that Ec propagates causally for all the charge distributions considered and the way in which E⊥ can be obtained from Ec is illustrated. In addition it is shown that the radiation-reaction force is very simply related to the force exerted on the charge by Ec alone. In this way the details of the time dependence of the radiation-reaction force can be understood in terms of the behaviour of the field during self-dressing. It is argued that the results obtained for the classical model are capable of shedding light on fundamental issues of quantum electrodynamics, such as the theory of measurement of the field amplitude and the onset of irreversible behaviour during self-dressing.

Well differentiated liposarcoma are rare tumours in the young age. The authors present a case of a 20 year-old woman, gravida 0, with a large pelvic retroperitoneal tumour. Clinical examination revealed the presence of a 10 cm diameter soft mass localized in the left pelvis. This mass deviated rightwards the uterus and cervix and caused a bulging perineum on the left side. Pelvic ultrasound and computerized tomography revealed a fatty lesion displacing the pelvic structures without invasion of the surrounding structures. The patient underwent surgery with laparotomic approach: a 500-g non-encapsulated lipomatous mass was removed by blunt dissection from the paravaginal space. Pathologic examination revealed a well-differentiated lipoma-like liposarcoma. On the basis of the differential diagnosis of pelvic retroperitoneal lesions, the liposarcoma management is discussed and the pathologic classification is pointed out.

An approximation method, suitable for an analytical treatment of the Kramers-Henneberger potential in three dimensions, is presented. The method is applied to various potentials which are currently used in one and three dimensions with reference to the problem of an electron in a strong field. This approach is shown to lead to a better understanding of the approximations previously adopted to deal with Coulomb and with localized potentials. Moreover, in the case of polynomial potentials of the double-well form, the method predicts a striking change in the dynamics of the electron for suitable values of the physical parameters.

We present a theory of harmonic generation by a strongly driven atom within the framework of non-relativistic QED. The atom is assumed to possess a finite number N of levels and ionization is neglected. This atom is dressed by the driving field using a unitary time-dependent transformation. Within the quasistatic approximation this transformation is shown to lead from the bare to the Floquet atom. The interaction of the Floquet atom with the vacuum modes is derived and it is shown to give rise both to the high-order harmonic and to the hyper-Raman spectrum. In the case N=2 the spectrum of the light scattered into the vacuum modes can be evaluated analytically and it is shown to consist of two parts. Neglecting interference between these two parts, the first of them is the high-order harmonic spectrum displaying peaks at the odd harmonics of the driving field. The second part is the hyper-Raman spectrum which has finite bandwidth and which displays peaks at the even harmonics of the laser frequency, centred at the Stark-shifted natural atomic frequency. These two spectra partially overlap and they are discussed in various ranges of intensity of the driving field, both in the minimal coupling and in the multipolar scheme. The results support recent suggestions that the presence of the plateau is related to interference between the two spectra. The dependence of the high-order harmonic spectrum from the driving field intensity is found to be related to that of the hyper-Raman spectrum in such a way that when the former increases the latter decreases and vice versa. It is argued that this might help to explain the non-visibility of the hyper-Raman lines when the high-order harmonics are visible.

It is acknowledged that the expression obtained by Hnizdo (Hnizdo V 1999 Phys. Rev. A 60 4191) in integral form for the time-averaged radiation reaction force RR is correct. It is shown that our expression (Compagno G and Persico F 1999 Phys. Rev. A 60 4196) for the same quantity is also correct, contrary to Hnizdo's claim.

In this paper we discuss isotopic effects in simple molecular ions subjected to strong laser fields. We show that the intensity of the emitted spectra strongly depends upon both the nuclear mass of the molecular ions and the laser pulse duration. In particular, for short pulse duration [up to 8 optical cycles (o.c.)], we confirm the trend described in the most studied case in which the high-order harmonic generation is more efficient for heavier isotopes; in contrast, an interesting physical phenomenon is predicted for pulses longer than 16 o.c. characterized by an inverse effect in which lighter molecular species are responsible for higher-order harmonic emission.

A new scheme to generate isolated attosecond pulses is presented that involves the use of a laser field and of a unipolar field. The laser field has a pulse of intensity I = 1.5×1014 W cm−2 and wavelength λ = 820 nm. The unipolar pulse is an asymmetric pulse consisting of a sharp peak, lasting approximately half a laser period, i.e. nearly 1.4 fs, followed by a long and shallow tail. We show that on combining these two fields, it is possible to generate isolated attosecond pulses as short as 1/10 of a laser period, i.e. approximately 270 as. Moreover, it is argued that this scheme is robust either against small variations of the laser envelope, or against small changes in the delay between the laser pump and the unipolar pulse.

We propose a new scheme to produce isolated attosecond pulses, involving the use of three laser pulses: a fundamental laser field of intensity I = 3.5 × 1014 W cm−2 and of wavelength λ = 820 nm, and two properly chosen weak lasers with wavelengths 1.5λ and 0.5λ. The three lasers have a Gaussian envelope of 36 fs full width at half maximum. The resulting total field is an asymmetric electric field with an isolated peak. We show that a model atom, interacting with the above-defined total field, generates an isolated attosecond pulse as short as 1/10 of a laser period, i.e. approximately 270 as.

La methode de preparation est basee sur la fluoration directe de polyesters lineaires (le poly(succinate d'ethylene)), suivie d'un traitement par les quantites non-stoechiometriques de SF 4 puis d'une hydrolyse des fonctions ester residuelles pour donner les oligomeres RO 2 C-(CF 2 ) 3 -[OCF 2 CF 2 O(CF 2 ) 4 ] n -O CF 2 CO 2 R (n=0, 8, R=H, Me). L'influence des quantites de SF 4 utilisees sur la structure des composes est etudiee par RMN et spectrometrie de masse

In this paper we show how it is possible to investigate the nuclei dynamics of a D2+ molecular ion by using the high harmonic generation spectra emitted by the system when subjected to an intense laser field. In particular, the emitted spectra contains, in addition to the usual odd harmonic peaks, additional satellite peaks whose frequency spacing is equal to the vibrational frequency of the nuclei.

The problem of nonlocality in the dynamical three-body Casimir-Polder interaction between an initially excited and two ground-state atoms is considered. It is shown that the nonlocal spatial correlations of the field emitted by the excited atom during the initial part of its spontaneous decay may become manifest in the three-body interaction. The observability of this new phenomenon is discussed., Comment: 17 pages, 1 figure, sub. to Phys. Rev. A

Carotid endarterectomy (CEA) has a positive effect on stroke free survival in patients with either symptomatic or asymptomatic severe carotid bifurcation stenosis. However, most trials have excluded elder patients. In addition, concerns have arisen regarding the benefits of CEA in the elderly population, especially in women. In this study, we performed an outcome analysis in patients undergoing CEA comparing those eighty and older to their younger counterparts. A total of 262 carotid operations were performed under local anaesthesia between 1998 and 2004; 76 (34%) were carotid reconstructions in 70 patients over 75 yr of age. Twenty patients (26%) presented with asymptomatic critical stenosis. Transient ischemic symptoms were the reason for presentation in 35 patients (46%). Progressive stroke was documented in two patients (3%) and a stroke with persisting neurological deficit was demonstrated in 19 cases (25%). Coronary artery disease was present in 47 patients (38%) and arterial hypertension in 55 (72%). Fifty-nine patients (84%) were classified as ASA group 3. Seventy-one thromboendarterectomies of the carotid bifurcation with direct closure were performed. Five patients had other types of reconstruction. Postoperative complications occurred in three patients. One had a transient neurological deficit and another a lethal stroke; the third patient died from myocardial infarction. The in-hospital mortality was 2.9%, which was not significantly higher than the results of the reconstructions in younger patients (1.5%). Surgery for carotid artery occlusive disease under local anaesthesia can be safely performed in selected patients of more than 75 yr of age.

This paper reviews the main results of a twenty year-long international collaborative effort led by the late E.A. Power on the physics of atoms dressed by the vacuum electromagnetic field. The presentation uses the historical, rather than the logical, order of development. This permits one to shed light on the influence of Power's personality and human qualities on the birth and evolution of the notion of the dressed atom, which is central to modern non-relativistic QED.

We consider the three-body Casimir-Polder interaction between three atoms during their dynamical self-dressing. We show that the time-dependent three-body Casimir-Polder interaction energy displays nonlocal features related to quantum properties of the electromagnetic field and to the nonlocality of spatial field correlations. We discuss the measurability of this intriguing phenomenon and its relation with the usual concept of stationary three-body forces., Comment: 4 pages

The three-body Casimir-Polder potential between one excited and two ground-state atoms is evaluated. A physical model based on the dressed field correlations of vacuum fluctuations is used, generalizing a model previously introduced for three ground-state atoms. Although the three-body potential with one excited atom is already known in the literature, our model gives new insights on the nature of non-additive Casimir-Polder forces with one or more excited atoms., 9 pages

We have considered the interaction of a pair of spatially separated two-level atoms with the electromagnetic field in its vacuum state and we have analyzed the amount of entanglement induced between the two atoms by the non local field fluctuations. This has allowed us to characterize the quantum nature of the non local correlations of the electromagnetic field vacuum state as well as to link the induced quantum entanglement with Casimir-Polder potentials., Published on Europhysics Letters 78 (2007) 30003

Endoscopic stent insertion has become the preferred method for palliation of malignant biliary obstruction. Currently, endoscopic stent placement involves the use of contrast media and radiological equipment to achieve direct opacification of the biliary duct systems, and to determine the location and the extension of biliary obstruction. This report proposes a new combination of ultrasonography and biliary endoscopy, with endoscopic stent placement entirely performed under US-guidance.US-guided stent placement was carried out in 8 patients. A guide-wire and a guiding-catheter were endoscopically introduced and identified, by US, the common bile duct across the stricture. Hydromer-coated polyurethane angled stents (10F) were finally inserted over the guide-wire/guiding-catheter by a pusher tube system.Successful stent insertion was achieved in all patients. There were no complications. Successful drainage, with substantial reduction in bilirubin level, was achieved in all patients (14.2+/-9.5 vs 4.2+/-2.9 mg/dl at 1 week).Endoscopic stent placement performed under US-guidance, is safe and effective. Further studies in a larger series, including more proximal strictures are suggested.

We consider the Casimir-Polder interaction between two atoms, one in the ground state and the other in its excited state. The interaction is time-dependent for this system, because of the dynamical self-dressing and the spontaneous decay of the excited atom. We calculate the dynamical Casimir-Polder potential between the two atoms using an effective Hamiltonian approach. The results obtained and their physical meaning are discussed and compared with previous results based on a time-independent approach which uses a non-normalizable dressed state for the excited atom., Comment: 11 pages

We calculate the Casimir-Polder intermolecular potential using an effective Hamiltonian recently introduced. We show that the potential can be expressed in terms of the dynamical polarizabilities of the two atoms and the equal-time spatial correlation of the electric field in the vacuum state. This gives support to an interesting physical model recently proposed in the literature, where the potential is obtained from the classical interaction between the instantaneous atomic dipoles induced and correlated by the vacuum fluctuations. Also, the results obtained suggest a more general validity of this intuitive model, for example when external boundaries or thermal fields are present., 7 pages

The outcomes of endoscopic biliary drainage for malignant stenoses at the hepatic hilum were retrospectively evaluated.From January 1990 to June 2001, 583 patients, 368 males, average age 69+/-18.5 years, were recruited. Endoscopic procedure consisted of insertion of 1 ore multiple stents, plastic or metallic, across the stricture, under mild sedation.Successful stent insertion was achieved in 518/583 (88.8%) patients and successful drainage in 474 (81.3%) patients. Early complications were observed in 101 (17.3%) patients with related-mortality of 17 (2.9%) patients. Late complications occurred in 39.9% of patients. Survival was of 189 days, on average.Endoscopic palliation should be the initial management of choice for malignant biliary stenoses at the hepatic hilum.

A short review is presented of the theory of dressed states in nonrelativistic QED, encompassing fully and partially dressed states in atomic physics. This leads to the concept of the reconstruction of the cloud of virtual photons and of self-dressing. Finally some recent results on the classical counterpart of self-dressing are discussed and a comparison is made with the QED case. Attention is drawn to open problems and future lines of research are briefly outlined.

A time-dependent Casimir–Polder force is shown to arise during the time evolution of a partially dressed two-level atom. The partially dressed atom is obtained by a rapid change of an atomic parameter such as its transition frequency, due to the action of some external agent. The electromagnetic field fluctuations around the atom, averaged over the solid angle for simplicity, are calculated as a function of time, and it is shown that the interaction energy with a second atom yields a dynamical Casimir–Polder potential between the two atoms.

The Bohr-Rosenfeld measurement theory of the electromagnetic field amplitude is applied to a needle-like detector. The expression of the time average of the self-force due to the measurement process is explicitly obtained. It is shown that the appearance of divergences does not allow the approximations required by the Bohr-Rosenfeld theory.

This book provides a comprehensive introduction to the theory of the interaction between atoms and electromagnetic fields, an area which is central to the investigation of the fundamental concepts of quantum mechanics. The first four chapters describe the different forms of the interaction between atoms and radiation fields. The rest of the book deals with how these interactions lead to the formation of dressed states, in the presence of vacuum fluctuations, as well as in the presence of external fields. Also covered are the role of dressed atoms in quantum measurement theory, and the physical interpretation of vacuum radiative effects. Treating a key field on the boundary between quantum optics and quantum electrodynamics, the book will be of great use to graduate students, as well as to established experimentalists and theorists, in either of these areas.