Finite confinement potentials, core and shell size effects on excitonic and electron-atom properties in cylindrical core/shell/shell quantum dots.

The effects of confinement potentials of the first and second materials, core size and first shell thickness on the confinement of electron, electron-donor atom, and exciton in cylindrical core/shell/shell quantum dot (CSSQD) are studied taking into account the finite confinement potential model. The confinement of charge carriers in CSSQD with two finite confinement potentials models of the barrier materials are studied. Within the effective mass and parabolic band approximation, the 3D time-independent Schrödinger equation has been resolved. To obtain the ground state quasiparticles energies, we have used the variational technique. Our results show that the donor atom and exciton binding energy, as well as the electron energy, strongly depend on the core radius, first shell thickness, confinement potentials of the barrier materials, and their structures (A and B). Moreover, the confinement potential effect of the first material on the energies is more pronounced when their thickness is large and the core radius is small. So, the external potential effect is more significant when the first shell thickness and potential are small. Also, The binding energy of an on-center (off-center) donor atom is greater (weaker) than that of the exciton, whatever the structure of the confinement potential. In addition, the transition from a type-A to a type-B confinement system has been observed. The findings might be used to modify the electronic and excitonic properties in nanomaterials science.

Quality of life of children operated for bladder exstrophy.

INTRODUCTION: Bladder exstrophy is a rare malformation with functional and psychological issues affecting children's quality of life. This study aims to evaluate the urinary continence and the quality of life of patients operated for bladder exstrophy in our institution. METHODS: This is a retrospective study including fifteen patients operated for bladder exstrophy between 1995 and 2015. All patients underwent a physical examination and an interview with a psychiatrist. Urinary continence was evaluated by dryness periods. Quality of life was evaluated by the QoL SF-36 scale. RESULTS: All patients underwent primary early bladder closure. Posterior osteotomy was performed initially in 6 cases, and during the redo surgery in 7 cases. Leakage was recorded in 4 cases, fistula in 9 patients. Twelve patients had one or more redo surgery. Final bladder closure success rate was of 80%. Additional continence surgical procedures were performed by a Young Dees technique in 8 cases and with bladder enlargement associated with Mitrofanoff continent derivation in 5 cases. Only two patients over fifteen did not use diapers. All the items of QoL score according SF-36 were under the normal value (75%) except physical functioning and physical limitation. These scores go worst with age. Scores were better for continent boys in both physical and psychological items, but the difference was not significant However, significant difference was observed between boys having less than 3 surgeries and those having more than three procedures. Psychological and social scores were better for girls than for boys and differences were significant. CONCLUSIONS: The risk of urinary incontinence is high in children managed for bladder exstrophy. Boys are more affected than girls with subsequent psychological and social repercussions. In our study, quality of life depends more on number of surgery than continence results. Psychological problems should be screened early for accurate treatment. LEVEL OF EVIDENCE: 3.

Soft-tissue necrosis complicating tibial osteotomy in a child with Proteus syndrome.

INTRODUCTION: Proteus syndrome is a rare congenital hamartomatous disease frequently responsible for musculoskeletal deformities. The results and complications of surgical treatment are not well documented owing to the scarcity of reported cases. CASE REPORT: The authors report a case of poor evolution of valgus proximal tibial osteotomy in a 6-year-old girl with Proteus syndrome. The surgery was complicated by extensive deep wound necrosis exposing the tibial bone, necessitating surgical excision, antibiotherapy and controlled wound healing. At 1 year postoperatively, the deformity recurred. DISCUSSION: The possibility of serious wound complications and of recurrence must be kept in mind when operating on a limb deformity in patients with Proteus syndrome. Potential complications should be taken into account in selecting the surgical correction technique: epiphysiodesis may be preferable to osteotomy.