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Acquired hypoganglionosis or aganglionosis after surgery for Hirschsprung's disease is a littler described situation. To investigate and describe the mechanism of acquired aganglionosis or hypoganglionosis following sugery in the pulled-through bowel which had been previously confirmed as ganglionated.

TiO 2 thins films were prepared on Si (100) substrates by a sol-gel dip coating process. Effect of the annealing temperatures in different atmospheres (air and O 2 ) on the properties of the films has been examined. FTIR results indicated a dominant feature centred around 438 cm –1 , which is characteristic of the anatase TiO 2 . This peak is quite sharp at higher temperature, indicating the film is well-crystallised, especially for the film annealed at 500°C under oxygen. The bands at 3,400 and 1,620 cm –1 represented the stretching and bending vibrations of O-H hydroxyl groups, and those bands could be normally reduced by the calcination process. The morphology of the films annealed at 500°C under air and oxygen showed relatively uniform surface, densely packed nanoparticles and quite low mean average roughness values. The determination of the refractive index, packing density and the band gap by the ellipsometry is presented.

Pediatric female urethral injury is rare and the management remains non consensual. Patients presenting at a later stage with obliterate strictures have limited surgical options for repair. The aim was to report an original endosurgical procedure to recreate the urethra after a complete urethral rupture

Some investigations on physico-chemical properties of hydrogenated amorphous carbon (a-C:H) thin films deposited from C2H4 precursor have been carried out. The films were elaborated in a Microwave Multipolar Plasma reactor excited at Distributed Electron Cyclotron Resonance (MMP-DECR). The effects of the plasma power on the electrical and structural characteristics of the deposited films have been evaluated. It appeared that for low plasma power ( 400 W), the deposition rate and the hydrogen concentration increases, whereas the Csp2 concentration remains constant. Beyond 400 W, the deposition rate and the hydrogen concentration reach saturation levels and the Csp2 concentration decreases. In contrast, the film density decreased with the increase of the plasma power. Below 400 W, the dielectric constant decreased with the increase of the plasma power, however, beyond 400 W its value remained almost constant. The correlation between film characterization and properties shows that the permittivity is driven by the film density and the film structure.

Humidity sensors are widely used in industry production, process control, environment monitoring, medical and electrical applications. In this study, water molecule sensitive layers have been elaborated by plasma enhanced chemical vapor deposition PECVD technique, from a mixture of hexamethyldisiloxane (HMDSO) and oxygen (O2) in different proportions. The films were deposited on a comb-shape aluminum electrode evaporated on glass substrate. Electrical and structural characteristics of the elaborated humidity sensors were evaluated by humidity-impedance characteristics, infrared spectroscopy FTIR and ellipsometric analysis. Electrical analysis showed that the elaborated humidity sensor exhibited a detectable response to relative humidity ranging from 35 to 95%. However, increasing O2 concentration in the mixture during deposition, leads to a significant decrease of the sensor sensibility. A sensor elaborated with pure vapor of HMDSO exhibited a better sensibility. FTIR analysis revealed that increasing O2 concentration induces a decrease of methyl groups CH3 and the formation of Si-O groups leading to film densification. Besides, the values of the refractive index deduced from ellipsometric data indicated that the refractive index increases with increasing the O2% in the mixture. This observation may be considered as further evidence to film densification.

Thin SiOF films were elaborated in microwave excited DECR plasma reactor (Distributed Electron Cyclotron Resonance) from a mixture of hexamethyldisiloxane (HMDSO) and oxygen (O2) (in 1: 9 proportion) with the presence of various CF4 concentrations. The fluorine contents in the films composition were adjusted by the CF4 gas flow ratio (in the range of 10 - 70%). The refractive index and the deposition rate were estimated from ellipsometric data and the film chemical structure was studied by FTIR analysis technique. The deposition rate increases with increasing CF4 flow and then decreases after reaching a maximum value for 20% of CF4. The decrease in the deposition rate may be attributed to the etching effect by CF4 plasma during the deposition process. As the additive fluorine concentration increases, the intensity of Si–F peak stretching vibrations located at 930 cm-1 increases and the frequency of the Si–O stretching vibration mode centered at 1060 cm-1 shifts towards higher wavenumber.

The effects of process parameters such as O2/HMDSN (hexamethyldisilazane) ratio, microwave discharge power and deposition pressure on the growth rate, chemical bonding nature, and refractive index of thin films deposited by microwave plasma from HMDSN with oxygen, have been investigated. The plasma was created in a Microwave Multipolar reactor excited by Distributed Electron Cyclotron Resonance. The films were deposited at room temperature and characterized by Fourier Transform Infrared spectroscopy and ellipsometry. Growth rate increased with the discharge power Por the deposition pressure but decreased significantly with increasing O2/HMDSN ratio. A large change in the film composition was observed when the O2/HMDSN ratio was varied: films deposited with only HMDSN precursor are polymer-like but as the O2/HMDSN ratio increased, organic groups decreased. For relative pressure values over 70%, deposited films are SiO2-like with refractive index values close to those found for thermal silicon dioxide.

The high-frequency characteristics of semiconductor lasers are described using an equivalent circuit model. The paper investigates the small-signal intensity modulation (IM) and frequency modulation (FM) when the parabolic gain approximation is used and when lateral diffusion of carriers in the active region of the laser is taken into account via a one-dimensional diffusion equation. We have performed the small-signal analysis to give a more transparent description of the influence of parabolic gain approximation on the modulation response. The inclusion of parabolic gain approximation and the gain compression characteristics of the active region in the expression derived for IM, FM and the chirp-to-modulated power ratio allows the present model to reflect the influence of the laser structure on the modulation performances.

An equivalent-circuit model of a semiconductor laser is developed. The model includes diffusion and uses the parabolic gain approximation. It can be applied to various buried heterostructure (BH) devices to simulate optical response characteristics. The values of the circuit elements versus injection current clearly indicate that the parabolic gain approximation and carrier diffusion play an important role in obtaining a more accurate frequency response, especially for (BH) lasers with stripe widths greater than the diffusion length.