Search

Introduction: Ganglioneuromas are tumors of neurogenic origin usually located in the abdomen, the adrenal glands, and the mediastinum but infrequently found in the neck region. Case Presentation: We describe the case of a four-year-old Albanian girl presenting with an anterior neck mass initially suspected to be a thyroid nodule. From a clinical point of view, there was no evidence of compression on vital cervical structures. Lab tests detected normal serum thyrotropin, calcitonin, and parathormone concentrations. A neck ultrasound showed a huge mass apparently originating from the left thyroid lobe. Cytological examination of fine needle biopsy demonstrated a population of large cells with eosinophilic cytoplasm, regular nuclei, and prominent nucleoli and spindle cells without significant atypia, consistent with a benign lesion of neurogenic origin. Also, the neck MRI displayed a mass with well-defined margins, likely arising from the peripheral nervous system. The patient underwent surgical excision of the mass without complications. The histological exam was diagnostic for ganglioneuroma. Conclusions: We discuss the cytological and histological features peculiar to such a rare neck lesion and review the differential diagnosis.

Internal carotid artery (ICA) injuries during endoscopic endonasal surgery (EES) are rare life-threatening events. We describe a technique to manage ICA injuries based on the use of Foley catheters.A 26-year-old female underwent endoscopic transnasal trans-sphenoidal removal of pituitary adenoma. Cerebrospinal fluid leak occurred 4 days postoperatively. During repair procedure, accidental injury of ICA occurred. Emergency nasal packing through positioning of four Foley urologic catheters was successfully performed to stop bleeding. The patient did not report neurologic deficits.In author’s opinion, Foley catheters are suitable to obtain immediate bleeding control since they are rapidly available and easily usable.

Intrinsic facial nerve tumors are rare lesions. Among the different histology types, schwannomas is the most frequently reported in literature. Other histological types of facial nerve tumors are hemangiomas, meningiomas, and neurofibromas. Chorda tympani schwannomas (CTSs) are extremely rare entities and are considered as an independent subgroup of facial nerve schwannomas because of their clinical characteristics. The aim of this report is to present the clinical and radiological features and the management of a CTS in a 27-year-old male presenting with conductive hearing loss.

Multiple theories have been discussed about the etiopathogenesis of congenital middle ear cholesteatoma (CMEC) and its specific site of origin. The intraoperative identification of the precise location of the keratinous mass is important to guarantee its complete removal, in order to reduce the risk of recurrence. This study proposes the tensor tympani tendon (TTT) as a possible site of origin of CMEC. All CMECs treated between 2013 and 2019 were reviewed. Only Potsic stage I lesions were included. Preoperative radiologic images were compared to intraoperative findings. Three removed TTT were sent for histologic evaluation. Seven patients were included (M:F = 3:4). Preoperative CT images were classified as type A in 2 cases (28.6%) and type B in 5 cases (71.4%). At intraoperative evaluation all CMEC sacs were found pedunculated on the TTT. The histologic examinations confirmed the connection between the cholesteatomatous sac and the TTT. According to the correlation of imaging, intraoperative findings and histology, we proposed that the TTT could be the primary site from which CMEC originates.

Tracheocele is a herniation of the tracheal mucosa through a defect in the tracheal wall. Familiar and/or genetical factors have never been taken into consideration in the etiopathogenesis of acquired tracheocele. Acquired tracheocele occurred in a brother and a sister from India. CT scan of the neck showed an air cyst next to the right tracheal wall. They underwent surgical excision through a transverse cervical incision. Histopathology of the lesion revealed a fibrous sac lined by a pseudostratified columnar respiratory epithelium in both patients. They had no recurrence of tracheocele at 12months follow up. Genetic counseling did not evidence any significative associated abnormalities. No previous cases of familiar acquired tracheocele have been reported in the literature. Given the rarity of the lesion occurring in more than one member of a family, hereditary factors could be supposed as contributing factors in the etiopathogenesis of acquired tracheocele.

Myringotomy and ventilation tube placement are procedures usually indicated for middle ear effusion with persistent conductive hearing loss. Although tympanostomy tube placement is a well-known technique and is considered a simple and low-risk procedure, sometimes there can be significant complications associated with this approach, like otorrhea, displacement of the device, and persistent perforation of the tympanic membrane. The two main advantages of the endoscopic approach for myringotomy and ventilation tube positioning are the possibility to work better in case of stenotic or tortuous external auditory canal and the enhanced visualization that can allow us to identify vascular abnormalities medial to the tympanic membrane, avoiding critical complications.

Objectives To develop and validate an ex-vivo dissection model suitable for open laryngeal surgery (open partial laryngectomy and total laryngectomy) training. Methods A fresh ex-vivo 6-months old ovine model was tested by experienced laryngologists and validated during two international dissection courses on open laryngeal surgery held in December 2018 and 2019. Each participant completed a survey to subjectively evaluate the dissection experience. Likewise, four experienced laryngologists rated their experience. Statistical comparison of these ratings was performed. Results The suitability of the ex-vivo ovine model for open laryngeal surgery was assessed among 28 head and neck surgeons with a mean experience of 6.3 years and 4 expert laryngologists. The feedback from all the participants was excellent with a mean overall impression of 9.5 (± 0.7 SD) and a mean recommendation score of 9.6 (± 0.6 SD) for further use. No statistically significant differences were found comparing neither the overall grade (p= 0.63) nor the recommendation rating (p= 0.24), testifying that even for expert laryngologists this remains a viable model for open laryngeal surgery training. Conclusions The complexity of open laryngeal surgery makes simulation an attractive option for developing skills that are transferrable to operating setting. Due to the anatomic resemblance with the human, the ex-vivo ovine model is herein proposed as a training model for open laryngeal surgery. Validation among beginners and expert laryngologists revealed its suitability as effective teaching means in laryngectomies.

Purpose: To assess the anatomical and functional outcomes of endoscopic transcanal tympanoplasty type I for tympanic membrane perforations. Methods: Eight hundred thirty-five patients who underwent tympanoplasty between January 2011 and January 2019 were selected. Patients with tympanic membrane perforation treated with a transcanal endoscopic tympanoplasty type 1 and a follow-up period longer than 6months have been retrospectively reviewed. The presence of cholesteatoma or ossicular chain dysfunctions were considered exclusion criteria. Eighty-one patients were included in the present study population. The main outcome was the rate of overall graft success. Secondary outcomes included hearing results. Prognostic factors related to both the abovementioned outcomes were assessed. Results: Overall, 66 patients (81.5%) had a successful graft at the last follow-up evaluation. Mean follow-up was 22.1 (range 6–104) months. The anterior quadrants were entailed by the perforation in 62 (76.5%) cases. The overall success rate with cartilage (or cartilage and perichondrium) was 91.2% (p < 0.01). The median preoperative and postoperative ABG were 18.7 (13.4–25.6) and 7.5 (2.5–12.5), respectively, revealing a significant median improvement of 11.2 (p < 0.001). The type of graft and the postoperative tympanic membrane status were significantly associated with the audiologic outcome with p = 0.01 and p = 0.02, respectively. Conclusions: Endoscopic tympanoplasty type I is a reliable technique with reasonable anatomic and audiologic results. Tympanic membrane grafting with cartilage (or cartilage and perichondrium) guarantees a higher rate of perforation closure and satisfactory hearing results. Anterior eardrum perforations can be successfully and safely managed with transcanal endoscopic approach avoiding postauricular approach and canalplasty.

none

Backgroud Hemangiomas are the most common benign vascular tumors which most frequently occurs in newborns and infants. The skin of head and neck district is often involved, whereas the oral cavity and oropharynx do not. There are many different strategies for the management of head and neck hemangiomas, including wait and see policy, drug therapy, sclerotherapy, cryotherapy, radiotherapy, laser therapy and surgery. The treatment plan must consider aspects such as size, location, lesion hemodynamics and patient’s age. Case presentation We describe a case of a 38-years-old male complaining dysphagia, dyslalia and dyspnea, moreover, the patient referred episodic bleeding from the oral cavity. At clinical examination a giant vascularized lesion involving the tongue and occupying almost all the oral cavity and oropharyngeal space was observed. Surgical approaches for macroglossia can be considered in case of benign vascular lesion of the tongue when other therapies have failed and/or patient’s clinical condition requires early intervention. Conclusions The aim of this case report is to describe our surgical strategy to manage a giant vascular malformation of the tongue and improve quality of life through a median glossectomy with trapezoidal wedge resection of the tongue, as previously described for surgical management of macroglossia.

We measure the coefficients of self capacitance C 11 and of interelectrode capacitance C 12 of a pair of square parallel plates, by using commercial models of capacitance to digital converters. The measured coefficient depends on which charge is sampled, that of the excited electrode or that of the other one. The analysis of the data at large distances is in agreement with the asymptotic formulas for the capacitance coefficients. The different leading behaviour as a function of the distance gives coherent independent estimations of the intrinsic capacitance of a single plate, in good agreement with the calculated one.

We study the force between two circular electrodes in different configurations. A formula analogous to Kelvin's formula for the spheres is given in the case of equal disks held at the same potential and when one plate is earthed. An expression for the force at short distance between two arbitrarily charged disks is found: the generic case shows a logarithmic repulsive force, also for disks carrying charges of opposite sign. Some numerical computations support the results. A classification for the possible behaviors of the force is proposed on the basis of a decomposition of the capacitance matrix. It is shown that the forces depend strongly on the dimensionality of the contact zone between the conductors. The analysis is supported by a numerical computation carried for the case of two disks of different radii., 17 pages, 4 figures

Some new results are presented concerning the forces between two equal circular electrodes of finite thickness. For close electrodes different scenarios result, depending on the thickness and on the ratio of charges of the conductors. Attractive or repulsive forces can appear depending on the parameters and on the separation of the electrodes. The force between the electrodes can be non monotonic as a function of the distance and one or more equilibrium points can appear. A unified description of cylindrical systems using a high precision method based on a Galerkin expansion is given and we check our results with a quite accurate boundary element method (BEM).

A numerical and semi-analytical study of electrostatics of a system of two parallel square electrodes is focused on the behavior at short and large distances of the capacity coefficients and of the electrostatic forces between the plates. It is found, using a Boundary Element Method approach with a regular grid and an analytical treatment of the kernel matrix, a strict parallelism with the analogous system of two circular disks, in particular for the possibility of disentangle the divergences at short distances and the presence of a logarithmically divergent repulsive force, with the exception of electrodes with exactly opposite charges. With our semi-analytical approach, fully exploiting the symmetries of the problem and using very small subdomains, the capacitance coefficients of the two square capacitor are determined with a great accuracy, comparable with the best data available in the literature just for the capacitance of a single square.

In a previous paper published in this journal (Ronzani et al 2008 Eur. J. Phys. 29 957), an estimate of the light speed in air, obtained by measuring the time of flight of a pulsed laser beam, was reported. Using the same method and apparatus, we have improved the measure of the light speed in air, by increasing the data sample, and measured the light speed in water, obtaining an estimate of the water refractive index equal to n = 1.323 (0.016), at the wavelength of 665 nm.

The design of capacitive sensors and devices for new and emerging applications would benefit from simple and reliable methods to estimate the capacitance between conductors in terms of the capacitance of the isolated bodies and of the distance between them. The coefficients of potential and capacitance of a pair of conductor are approximated with the first terms of an expansion formula in the inverse of their distance. The form given applies to conductors of generic shapes and position in space. A comparison with the exact value for two spheres shows agreement even for rather small distances.

In this paper, we write a system of integral equations for a capacitor composed of two discs of different radii, generalizing Love’s equation for equal discs. We compute the complete asymptotic form of the capacitance matrix for both large and small distances obtaining a generalization of Kirchhoff’s formula for the latter case.

A simple experiment, suitable for performing in an undergraduate physics laboratory, illustrates electromagnetic induction through the water entering into a cylindrical rubber tube by detecting the voltage developed across the tube in the direction transverse both to the flow velocity and to the magnetic field. The apparatus is a very simple example of an electromagnetic flowmeter, a device which is commonly used both in industrial and physiological techniques. The phenomenology observed is similar to that of the Hall effect in the absence of an electric current in the direction of motion of the carriers. The experimental results show a dependence on the intensity of the magnetic field and on the carrier velocity, in good agreement with the theory. Discussion of the system, based on classical electromagnetism, indicates that the effect depends only on the flow rate, and is independent both of the velocity profile and of the electrical conductivity of the medium.

The time of flight (TOF) of a light pulse travelling back and forth and optical path length measurements are used to estimate the velocity of light. The light pulse has a duration of 10 ns, and is obtained from a suitably modified CW commercial laser diode. The TOF is read with a digital oscilloscope connected to two fast sensors, detecting the signals at the switch-on of a laser diode and at the arrival of the light pulse reflected from a plane mirror placed at a known distance.

The influence of a static magnetic field orthogonal to the axis of an argon laser discharge is investigated. The enhancement of the small-signal gain at 488 nm is measured as a function of the magnetic field at different values of the parameters of the discharge. The data about the gain compared with the measurement of the fluorescence from the upper level of the 488 nm line give information about the excitation mechanisms. A strong enhancement of the ionization rate of Ar+ is detected.

We evaluate the role of electron-ion mutual interactions as a possible source of systematic errors in an experiment of electron impact ionization and excitation of an effusive Ca beam. By monitoring photons resulting from the impact excitation of a Ca resonant transition, the transmitted electron beam current by a sectored Faraday cup and total ion yields, we extract information about elementary processes responsible for ionization. We show that our diagnosis allows us to monitor the influence of the produced ionization on the elementary processes and on the density profile of the electro beam.

We present a new, simple and cost effective scheme for the measure of the second-order correlation function of Nd-YAG laser second-harmonic (532 nm) pulses. We measure the transmission of a probe beam in a cell containing 6G-Rhodamine solution bleached by a counterpropagating pump beam. Under a convenient choice of experimental parameters, we can measure also the contribution of third-order correlation function.

A tunable diode laser has been used as a light source for line-of-sight absorption and Doppler-shift measurements. We have applied the method to perform plasma diagnostics in a magneto plasma dynamic (MPD) pulsed propulsor device and of an Ar/sup +/ laser tube plasma. Spectrally resolved argon absorption lineshapes of transitions of neutral and single ionized argon were recorded. A high temporal resolution (a few microseconds) is achieved by fast tuning the laser frequency at a repetition rate greater than 100 kHz. From the recorded spectra, we deduce the dynamics of the neutral components of the plasma in the thruster. We also demonstrate the possibility of direct ion diagnostics by the observation of ionic transitions, using red diode lasers in an Ar/sup +/-laser commercial tube.

The small satellite "Galileo Galilei" (GG) has been designed to test the equivalence principle (EP) to 10-17 with a total mass at launch of 250 kg. The key instrument is a differential accelerometer made up of weakly coupled coaxial, concentric test cylinders rapidly spinning around the symmetry axis and sensitive in the plane perpendicular to it, lying at a small inclination from the orbit plane. The whole spacecraft spins around the same symmetry axis so as to be passively stabilized. The test masses are large (10 kg each, to reduce thermal noise), their coupling is very weak (for high sensitivity to differential effects), and rotation is fast (for high frequency modulation of the signal). A 1 g version of the accelerometer ("Galileo Galilei on the Ground" — GGG) has been built to the full scale — except for coupling, which cannot be as weak as in the absence of weight, and a motor to maintain rotation (not needed in space due to angular momentum conservation). GGG has proved: (i) high Q; (ii) auto-centering and long term stability; (iii) a sensitivity to EP testing which is close to the target sensitivity of the GG experiment provided that the physical properties of the experiment in space are going to be fully exploited.

“Galileo Galilei” (GG) is a small satellite designed to fly in low Earth orbit with the goal of testing the Equivalence Principle—which is at the basis of the General Theory of Relativity—to 1 part in 1017. If successful, it would improve current laboratory results by 4 orders of magnitude. A confirmation would strongly constrain theories; proof of violation is believed to lead to a scientific revolution. The experiment design allows it to be carried out at ambient temperature inside a small 1-axis stabilized satellite (250 kg total mass). GG is under investigation at Phase A-2 level by ASI (Agenzia Spaziale Italiana) at Thales Alenia Space in Torino, while a laboratory prototype (known as GGG) is operational at INFN laboratories in Pisa, supported by INFN (Istituto Nazionale di fisica Nucleare) and ASI. A final study report will be published in 2009.

Model Driven Engineering (MDE) is increasingly gaining acceptance in the development of Web Applications as a mean to leverage abstraction and render business logic resilient to technological changes. This paper describes the beContent project with its modeling languages and tools, which aims at the automated generation of rich Web applications.

We present experimental evidence of the NonLinear Hanle Effect (NLHE) on the 488 nm transition in an active discharge of an argon laser. Experimental data are used to estimate the homogeneous linewidth of the upper level of the transition. The role of the NLHE in the laser power enhancement is also discussed.

An intense laser-induced fluorescence of sodium and of other alkali atoms (K, Rb) at room and lower temperatures has been observed in polysiloxanecoated cells, producing a vapor density of the metal which is much higher than that corresponding to the thermal equilibrium between the vapor and the condensed phase. This enhancement is attributed to the light-induced ejection of atoms absorbed by the polysiloxane coating. The atomic density of the vapor can be manipulated by changing either the laser power or frequency. The dependence of the atomic density on these and other parameters as well as its time-dependent behavior are studied experimentally. A tentative interpretation of the phenomenon is discussed in terms of the properties of solutions of the alkali metals in several solvents.

We consider the possibility of testing the equivalence principle (EP) in the gravitational field of the Earth from the orbits of LAGEOS and LAGEOS II satellites, which are very accurately tracked from ground by laser ranging. The orbital elements that are affected by an EP violation and can be used to measure the corresponding dimensionless parameter ? are semimajor axis and argument of pericenter. We show that the best result is obtained from the semimajor axis, and it is limited-with all available ranging data to LAGEOS and LAGEOS II-to ? = 2 × 10-9, more than 3 orders of magnitude worse than experimental results provided by torsion balances. The experiment is limited because of the non uniformity of the gravitational field of the Earth and the error in the measurement of semimajor axis, precisely in the same way as they limit the measurement of the product GM of the Earth. A better use of the pericenter of LAGEOS II can be made if the data are analyzed searching for a new Yukawa-like interaction with a distance scale of one Earth radius. It is found that the pericenter of LAGEOS II is 3 orders of magnitude more sensitive to a composition dependent new interaction with this particular scale than it is to a composition dependent effect expressed by the ? parameter only. Nevertheless, the result is still a factor 500 worse than EP tests with torsion balances in the gravitational field of the Earth (i.e. at comparable distance), though a detailed data analysis has yet to be performed. While EP tests with satellite laser ranging are not competitive, laser ranging to the Moon has been able to provide a test of the EP almost 1 order of magnitude better than torsion balances. We show that this is due to the much greater distance of the test masses (the Earth and the Moon) from the primary body (the Sun) and the correspondingly smaller gradients of its gravity field. We therefore consider a similar new experiment involving the orbit of LAGEOS: testing LAGEOS and the Earth for an EP violation in the gravitational field of the Sun. We show that this test may be of interest, though it is a factor 300 less sensitive than in the case of the Moon due to the fact that LAGEOS is closer to the Earth than theMoon and consequently its orbit is less affected by the Sun. The limitations we have pointed out for laser ranging can be overcome by flying in low Earth orbit a spacecraft carrying concentric test masses of different composition with the capability, already demonstrated in ground laboratories, to accurately sense in situ any differential effects between them.

Intrinsic absorptive bistability and hysteresis cycles in a steady-state regime are obtained at microwave frequencies. A theory is presented which takes into account the Gaussian shape of the fundamental mode excited into the resonator and is compared with the experimental results.

The behaviour of a Fabry-Perot microwave resonator, filled with a two-level absorber and fed by several e.m. waves of frequencies close to the absorber resonance, is investigated. The transmission as a function of the incident fields exibits multistability. Tristability has been experimentally observed by using ammonia as the saturable absorber and by feeding the resonator with a modulated wave.

In the OB experiments the commutation between the lower and upper branches of the bistability cycle (or viceversa) occurs within a time dependent on the relaxation rates of the cavity and of the absorbing medium. For an OB operation near the hysteresis region,the critical slowing- down phenomenon takes place and the commutation occurs with a time very long compared to the relaxation rates of the system. If a control parameter is modified by a step-function, the monitored output power of the bistable system reaches a new equibrium state after a delay time τD. A complete description of the transient regime is obtained only through a statistical analysis, where the intrinsic fluctuations and the external noise are included. Such a statistical analysis of the delay time in an optical bistability experiment has been recently presented for sodium atoms in an optical cavity [1].

In this experiment one utilizes a microwave confocal open resonator in the transmission configuration, having a Q factor of 5 105. The resonator is filled with ammonia gas at the pressure of 1 mTorr. A klystron oscillator, frequency stabilized on the 3-3 ammonia inversion line, feeds the resonator which is tuned at the same frequency. In these experimental conditions, if the input power PI is continuously increased from a low to a sufficiently high value, the output power changes abruptly from a low to a high value. For a fixed gas pressure, this change occurs at a fixed threshold input power Pup. The same occurs if the input power is continuously decreased from a high value; in this case one has Pdown< Pup, Pdownbeing the threshold power at which the system switches from the high to the low transmission state.

Evidence of bistability induced by radiation pressure in a system operating at millimeter bandwidth is presented. The transmittance of a microwave cavity equipped with a movable mirror becomes bistable under the variation of two control parameters: the incident field intensity and the incident field frequency. Good agreement between theory and experiment has been achieved.