Reading the phase of a Raman excitation with a multi-state atomic interferometer.

Atomic memories for flying photonic qubits are an essential ingredient for many applications like e.g. quantum repeaters. Verification of the coherent transfer of information from a light field to an atomic superposition is usually obtained using an optical read-out. In this paper we report the direct detection of the atomic coherence by means of atom interferometry. We experimentally verified both that a bichromatic laser field closing a Raman transition imprints a distinct, controllable phase on the atomic coherence and that it can be recovered after a variable time delay.

Squeezing a thermal mechanical oscillator by stabilized parametric effect on the optical spring.

We report the confinement of an optomechanical micro-oscillator in a squeezed thermal state, obtained by parametric modulation of the optical spring. We propose and implement an experimental scheme based on parametric feedback control of the oscillator, which stabilizes the amplified quadrature while leaving the orthogonal one unaffected. This technique allows us to surpass the -3 dB limit in the noise reduction, associated with parametric resonance, with a best experimental result of -7.4 dB. While the present experiment is in the classical regime, in a moderately cooled system our technique may allow squeezing of a macroscopic mechanical oscillator below the zero-point motion.

Experimental realization of quantum zeno dynamics.

It is generally impossible to probe a quantum system without disturbing it. However, it is possible to exploit the back action of quantum measurements and strong couplings to tailor and protect the coherent evolution of a quantum system. This is a profound and counterintuitive phenomenon known as quantum Zeno dynamics. Here we demonstrate quantum Zeno dynamics with a rubidium Bose-Einstein condensate in a five-level Hilbert space. We harness measurements and strong couplings to dynamically disconnect different groups of quantum states and constrain the atoms to coherently evolve inside a two-level subregion. In parallel to the foundational importance due to the realization of a dynamical superselection rule and the theory of quantum measurements, this is an important step forward in protecting and controlling quantum dynamics and, broadly speaking, quantum information processing.

Needle perforation of the bowel in childhood.

Accidental ingestion of foreign bodies occurs frequently in childhood. The majority of them are passed spontaneously, and conservative management generally is recommended for foreign bodies in the stomach and duodenum. However, in some cases, operative intervention should be considered to prevent undesirable complications, such as intestinal perforation. Two cases of intestinal perforation owing to accidental ingestion of a needle are reported.

Optically induced lensing effect on a Bose-Einstein condensate expanding in a moving lattice.

We report the experimental observation of a lensing effect on a Bose-Einstein condensate expanding in a moving 1D optical lattice. The effect of the periodic potential can be described by an effective mass dependent on the condensate quasimomentum. By changing the velocity of the atoms in the frame of the optical lattice, we induce a focusing of the condensate along the lattice direction. The experimental results are compared with the numerical predictions of an effective 1D theoretical model. In addition, a precise band spectroscopy of the system is carried out by looking at the real-space propagation of the atomic wave packet in the optical lattice.

Collective excitations of a trapped Bose-Einstein condensate in the presence of a 1D optical lattice.

We study low-lying collective modes of an elongated 87Rb condensate produced in a 3D magnetic harmonic trap with the addition of a 1D periodic potential which is provided by a laser standing wave along the axial direction. While the transverse breathing mode remains unperturbed, quadrupole and dipole oscillations along the optical lattice are strongly modified. Precise measurements of the collective mode frequencies at different heights of the optical barriers provide a stringent test of the theoretical model recently introduced [M. Krämer, Phys. Rev. Lett. 88, 180404 (2002)]].

[Urodynamic evaluation in children with enuresis]. / Lo studio urodinamico nei pazienti enuretici.

We performed an urodynamic study in enuretic children to evaluate the relationship between urodinamic findings and symptoms. We studied 175 patients, with age from 5 to 12 years, who presented with nocturnal enuresis: 45 monosymptomatic and 130 polysymptomatic (in association with urinary urgency, urge incontinence, etc.). Despite differences in symptoms, in 151 patients (86%) abnormal urodynamic findings were identified. Bladder instability was the most common disorder. However, mild abnormalities were found in the monosymptomatic patients. In treated patients urodinamic findings and clinical improvement were correlated. This study confirmed that most patients with nocturnal enuresis have cystometric abnormalities. Although possible etiologies of nocturnal enuresis are various, bladder dysfunction may be an underlying cause.

Esophageal achalasia and hypertrophic pyloric stenosis associated with a phytobezoar in an adolescent.

Esophageal achalasia is an uncommon condition in children. The authors report on a 14-year-old girl who showed a very unusual association of cardiospasm and hypertrophic pyloric stenosis with a gastric phytobezoar.

[Treatment of complications in hypospadias surgery: modern advancement]. / Il trattamento delle complicanze nella chirurgia dell'ipospadia: nuove prospettive.

BACKGROUND: With today's improved surgical techniques, complications in hypospadias surgery are seen less often, especially in distal form (1-5%). However, in proximal or complex hypospadias complications rate varied between 15 and 57%. Corrective surgery is mandatory in maior complications (urethrocutaneous fistulas, persistent chorde, urethral strictures, superficial skin separation). The search for the innovative surgical procedures and the optimal urethral substitute continues because each tissue has its particular shortcomings and disadvantages. METHODS: At our hospital complications occurred in 25 ( 15%) of 177 patients who underwent primary hypospadias repair between 1994 and 1998. 9 patients required further surgery to repair the complications of previous hypospadias operations performed at other institutions. When local epithelial tissue was not available, different surgical procedures were performed, using bladder or buccal mucosa graft and free or vascularized tunica vaginalis flaps. RESULTS: Follow up ranged from 3 to 6 years: the cosmetic and functional results were excellent. Small fistulas occurred in 3 patients and were corrected successfully in a subsequent surgical procedure using a tunica vaginalis wrap. CONCLUSIONS: The concept of using tunica vaginalis in urethral reconstruction represent a recent innovation. This tissue is a valid alternative in cases of multiple failed repairs.

[Predicting factors of vesicoureteral evolution in children]. / Fattori prognostici nell'evoluzione del reflusso vescico-ureterale in età pediatrica.

BACKGROUND: Despite the large number of children with reflux, management among urologists is still controversial. One of the most debated aspects is the choice between observation treatment or surgical treatment. METHODS: We assessed the natural course of children with vesico-ureteral reflux in the period 1990-1995, to correlate factors and identify patients with high risk of renal damage. We retrospectively reviewed the clinical course of 80 children with vesicoureteral reflux. Thirty-two were diagnosed during prenatal ultrasound scan. In the other cases urologic evaluation was requested because of urinary tract infections. The following data were analyzed: medical records, diagnostic and follow-up cystogram, renal imaging, medical therapy or surgical treatment carried out according to the reflux grade, diagnostic age, congenital reflux nephropathy or postnatal acquired scarring, voiding patterns, spontaneous resolution during medical management. Follow up ranged from 5 to 10 years. RESULTS: Vesicoureteral reflux resolved spontaneously in 29 patients: 25 were affected from moderate reflux, 4 from IV grade reflux. Surgical correction was carried out in 32 patients. Endoscopic treatment was performed in 25. Twenty-two children are still receiving prophylaxis and 12 were lost to follow-up. Congenital renal pathology correlate with poor outcome. CONCLUSIONS: The conclusion is drawn that there is a wide clinical variability in children with vescicoureteral reflux. The most important is host's susceptibility to urinary tract infection, but the severity of reflux, age of patients and congenital reflux nephropathy influence prognosis and long-term outcome.

[Microproteinuria as a marker of renal damage in children]. / La microproteinuria nella valutazione del danno renale in età pediatrica.

BACKGROUND: Elevated urinary levels of microproteinuria or renal enzyme have shown to be associated with renal injury. Data collected in children with vesico-ureteral reflux (VUR) or hydronephrosis have been evaluated to identify a means of predicting renal damage. METHODS: Levels of urinary microproteinuria (N-acetyl-beta-glucosaminidase, aminoalanina peptidase, lisozyme, beta(2)-microglobulin) were evaluated with immunoassay in catheterized or voided urine. The levels of urinary creatinine were also determined. Of the 85 children enrolled in this study 22 were affected from reflux, 16 had hydronephrosis. Urine was obtained from the bladder in all children and also from renal pelvis in 9 patients at surgery for ureteropelvic junction obstruction. In addition, urine was obtained from 27 patients with a variety of pathophysiological conditions (neoplasia, ematuria, parenteral nutrition, ecc.). Normal healthy controls were performed in 20 children who volunteered for the study. RESULTS: In the group of children affected from reflux urinary microprotein elevated levels were in 18. In children with hydronephrosis pathological findings were observed in 2 cases. Abnormal pattern was found in 27 patients as response to various agents. Data obtained in healthy children were normal. Sensitivity in reflecting renal damage makes urinary enzymes measurement attractive as an indicator of renal dysfunction. CONCLUSIONS: Urinary microproteinuria evaluation may be a useful marker of progression of renal injury in children with reflux. However, excretion level of these microproteins is not helpful in identifying upper tract obstruction in small children, but values arise in those left untreated.

Expansion of a coherent array of Bose-Einstein condensates.

We investigate the properties of a coherent array containing about 200 Bose-Einstein condensates produced in a far detuned 1D optical lattice. The density profile of the gas, imaged after releasing the trap, provides information about the coherence of the ground-state wave function. The measured atomic distribution is characterized by interference peaks. The time evolution of the peaks, their relative population, as well as the radial size of the expanding cloud are in good agreement with the predictions of theory. The 2D nature of the trapped condensates and the conditions required to observe the effects of coherence are also discussed.

Superresolution of pulsed multiphoton Raman transitions.

We have investigated higher order multiphoton Raman resonances with two pulsed optical frequencies. Multiphoton transfer with up to 50 photons is observed with milliwatts of laser power. We demonstrate that the spectral width of the multiphoton resonances can be far below the Fourier transform linewidth of the driving optical pulses. The functional dependence of the transition linewidth on the number of exchanged photons is found to vary with the pulse shape. Our experiment is performed with laser-cooled rubidium atoms confined in a CO2-laser optical dipole trap.

Josephson junction arrays with Bose-Einstein condensates.

We report on the direct observation of an oscillating atomic current in a one-dimensional array of Josephson junctions realized with an atomic Bose-Einstein condensate. The array is created by a laser standing wave, with the condensates trapped in the valleys of the periodic potential and weakly coupled by the interwell barriers. The coherence of multiple tunneling between adjacent wells is continuously probed by atomic interference. The square of the small-amplitude oscillation frequency is proportional to the microscopic tunneling rate of each condensate through the barriers and provides a direct measurement of the Josephson critical current as a function of the intermediate barrier heights. Our superfluid array may allow investigation of phenomena so far inaccessible to superconducting Josephson junctions and lays a bridge between the condensate dynamics and the physics of discrete nonlinear media.

Superfluid and dissipative dynamics of a Bose-Einstein condensate in a periodic optical potential.

We create Bose-Einstein condensates of 87Rb in a static magnetic trap with a superimposed blue-detuned 1D optical lattice. By displacing the magnetic trap center we are able to control the condensate evolution. We observe a change in the frequency of the center-of-mass oscillation in the harmonic trapping potential, in analogy with an increase in effective mass. For fluid velocities greater than a local speed of sound, we observe the onset of dissipative processes up to full removal of the superfluid component. A parallel simulation study visualizes the dynamics of the Bose-Einstein condensate and accounts for the main features of the observed behavior.

Ovarian cysts in newborns.

Before the introduction of ultrasonography (US), ovarian cysts in newborns were thought to be rare. With the extended use of real-time US, prenatal detection has increased. There is still considerable controversy regarding the best treatment of these neonatal findings. A total of 27 instances in 24 consecutive newborns of antenatally-diagnosed ovarian cysts were reviewed for US data, management, and outcome to assess the ante- and postnatal evolution of the cyst and establish appropriate therapy. The cysts detected during pregnancy were studied by repeated postnatal US studies. In 10 children (2 with bilateral cysts) the cyst evolved spontaneously toward regression. Fourteen patients were operated upon; 10 had complex and 4 (in 1 bilateral) had simple cysts. Cystectomy was employed when possible to preserve the ovarian parenchyma (3 cases); in the remaining cases oophorectomy was performed. Histologically, the cysts were of follicular origin or necrosis made a diagnosis impossible. US was found to be a helpful diagnostic tool for simple ovarian cysts, but could not reliably distinguish between benign and malignant tumors if a sonographically complex lesion was present. Based on our experience, surgical management of ovarian cysts should be reserved to complex masses. Simple cysts can be monitored safely by close US follow-up; surgery is indicated if the cyst fails to regress after several months or becomes symptomatic.

Temperature-selective trapping of atoms in a dark state by means of quantum interference.

We present a novel type of dark spontaneous-force optical trap. The trap is based on a velocity-selective inhibition of repumping light absorption produced by electromagnetically induced transparency. Accumulation of cold cesium atoms in a dark state is observed.

Birefringence in electromagnetically induced transparency.

(4)He 2 (3)S(1) --> 2 (3)P transitions at 1083 nm were laser probed in the presence of radiation that coupled the 2 (3)P level with the 3 (3)S(1) level in a ladder scheme. The metastable helium that was used was produced in a rf discharge. Significant atomic birefringence was detected, in addition to complete electromagnetically induced transparency. A simple theoretical model explains the experimental results.

Relationship between upper gastrointestinal bleeding and non steroidal anti-inflammatory drugs in children.

The authors evaluated the relationship between drug intake and upper gastrointestinal (GI) bleeding. The endoscopic files of the previous 2 years were reviewed and the incidence and age and sex distribution recorded. GI bleeding is indication for a high percentage of lower endoscopies and a low percentage of upper endoscopies. On the other hand, although rarer upper GI bleeding is more severe and frequently related to drug ingestion. About 50% of cases showed gastric erosions secondary to drug intake. A relation between gastric bleeding and paracetamol is considered, as is the possibility of preventing secondary severe bleeding by pharmacologic gastric protection in children with risk factors such as chronic use of other drugs or portal hypertension.

Ultrasonography and gastric emptying: evaluation in infants with gastroesophageal reflux.

We have applied ultrasonography to the evaluation of gastric emptying in children. Two different populations have been investigated: normal children and children with gastroesophageal reflux. All the patients were less than 6 months of age. The diagnosis of gastroesophageal reflux was defined by 24-h pH measurement. The technique, used to measure gastric emptying, is the one described by Bolondi et al. In this research we used the simplified method. All children had been submitted to the examination after 4-h fasting. The standard meal was the usual milk formula, 300 ml/m2 body surface area (BSA). A cross-section area of the gastric antrum was determined before a meal and every 15 min for 2 h. The examination was concluded after two measurements were equal to the basal one. The normal gastric emptying curve was determined by a control group. Patients with gastroesophageal reflux showed three different kind of gastric emptying: (a) normal gastric emptying in 20% of cases, (b) abnormal gastric emptying in 15% of cases, and (c) intermediate cases in which the plateau curve is abnormal but the end time of gastric emptying is normal. We defined these three kinds of curves as type I or normal, type III or abnormal, and type II or intermediate. The estimate of frequency in patients with gastroesophageal reflux is similar to the reported data of the literature.