Heat transfer in rough nanofilms and nanowires using full band ab initio Monte Carlo simulation.

The Boltzmann transport equation is one of the most relevant frameworks to study the heat transport at the nanoscale, beyond the diffusive regime and up to the micrometer-scale. In the general case of 3D devices, the particle Monte Carlo approach of phonon transport is particularly powerful and convenient, and requires reasonable computational resources. In this work, we propose an original and versatile particle Monte Carlo approach parametrized by using ab initio data. Both the phonon dispersion and the phonon-phonon scattering rates have been computed by DFT calculation in the entire 3D Brillouin zone. To treat the phonon transport at rough interfaces, a combination of specular and diffuse reflections has been implemented in phase space. Thermal transport has been investigated in nanowires and thin films made of cubic and hexagonal Silicon, including edge roughness, in terms of effective thermal conductivity, phonon band contributions and heat flux orientation. It is shown that the effective thermal conductivity in quasi-ballistic regime obtained from our Monte Carlo simulation cannot be accurately fitted by simple semi-analytical Matthiessen-like models and that spectral approaches are mandatory to get good results. Our full band approach shows that some phonon branches exhibiting a negative group velocity in some parts of the Brillouin zone may contribute negatively to the total thermal flux. Besides, the thermal flux clearly appears to be oriented along directions of high density of states. The resulting anisotropy of the heat flux is discussed together with the influence of rough interfaces.

Trans-rectal ultrasonography (TRUS) with lipiodol injection for localization of the prostatic apex before radiotherapy planning.

PURPOSE: To evaluate reliability of Trans-rectal ultra-sonography (TRUS) guidance with lipiodol injection for prostate localization before radiotherapy planning. MATERIAL AND METHODS: From October 1997 to March 2000, 31 patients with prostatic adenocarcinoma and six patients with anastomotic recurrence after radical prostatectomy had TRUS-guided injection of lipiodol. Two milliliters of lipiodol were injected into each side of the prostate and 1 ml into both seminal vesicles with a 22 Gauge CHIBA needle and US probe guide before radiotherapy planning. We had established a contrast quality index (0 for no prostate enhancement to 5 for efficient pacification without any diffusion). On simulation films, we had performed anatomic measurements for comparison with other anatomic studies. RESULTS: For all 37 patients, TRUS-guided injection was well tolerated. Among 31 patients with the prostate in situ, three had no apex opacification and 15 had no vesicle enhancement or peri-vesicle space diffusion. However, in 19 patients there was good contrast quality with an index score of > or =3. The majority of patients had prostatic apex between 1.5 and 3.5 cm from ischial tuberosities ligne (27 from 28 evaluable for apex). Among 19 evaluable patients, 15 had seminal vesicles 2-4 cm above the top of pubis. For six patients with anastomotic recurrence after radical prostatectomy, lipiodol was precious aid to locate it. We had only one failure because of a precocious bladder absorption relating to a delay which is too long between rectal probe locating and portal films. CONCLUSION: TRUS injection of lipiodol is a simple, inexpensive, relatively safe technique for localization of prostatic apex, but not appropriate for seminal vesicles enhancement. This is also an interesting method to locate anastomotic recurrence.

The tension-free transvaginal tape procedure in the treatment of female urinary stress incontinence: a French prospective multicentre study.

OBJECTIVE: To evaluate in a prospective multicentre study (five centres) the preliminary results regarding efficacy and morbidity of the new tension-free transvaginal tape (TVT) technique in the treatment of urinary stress incontinence (USI) in women. METHODS: From November 1996 to May 1999, 52 women of mean age 64 (range 37--91) years underwent the TVT procedure to treat isolated grade 2 or 3 USI (44 cases) or grade 1 or 2 USI associated with uterine or rectal prolapse surgery (8 cases). Twenty-nine patients (55.8%) presented recurrent USI (1--4 previous procedures). Clinical data showed urethrovesical junction hypermobility in 35 cases (67.3%), isolated intrinsic sphincter deficiency (ISD) in 17 cases (32.6%) and pelvic organ prolapse in 8 cases. Urodynamics confirmed ISD in 27 cases (51.9%) with a mean urethral closure pressure of 18.5 (range 7--25) cm H(2)O. All data were collected by surgeons on a questionnaire. RESULTS: The surgical procedure was performed under spinal cord anaesthesia in 82.7% of patients (local anaesthesia 11.5%) with a mean operation time of 30 (range 20--60) min for TVT implantation. Six bladder injuries (11.5%) were identified and the needle was repositioned. Mean hospital stay was 2.5 (range 1-7) days in the group who underwent TVT alone. Mean follow-up of continence was 15.2 (range 6--36) months: 83% of patients were dry and 17% were improved. Nine patients (17.3%) required self-catheterization for 2--10 days postoperatively. No recurrence of USI, defect healing or tape rejection were reported. CONCLUSION: TVT is a new technique for the surgical treatment of USI which is useful for recurrent cases. The advantages are simplicity, low morbidity, reproducibility and reduced operative time. These early results indicate the technique is effective in correcting incontinence and is locally well tolerated. But these are preliminary data and the long-term outcome on USI and the urethra is needed.

[Repair of female urinary incontinence with prolene "TVT": preliminary results of a multicenter and prospective survey]. / Cure d'incontinence urinaire féminine par bandelette de prolène "TVT": résultats préliminaires d'une enquête multicentrique et prospective.

OBJECTIVES: A multicentre, prospective study (6 private centres, 1 general hospital and 1 teaching hospital) was conducted to evaluate the perioperative morbidity and short-term functional results of the TVT procedure in the treatment of the female urinary stress incontinence. PATIENTS AND METHODS: From November 1996 to September 1999, 120 patients with a mean age of 65.2 years (range: 37-91) were operated according to the tension-free vaginal tape (TVT) technique for isolated urinary stress incontinence (stage 2 or 3) in 94 cases and associated with pelvic tone disorder in 26 cases. 59 patients (49.2%) presented recurrence of urinary incontinence that had already been operated between 1 and 4 times. Physical examination demonstrated hypermobility of the urethra in 73 cases (60.8%), isolated clinical sphincter incompetence in 47 cases (39.2%) and pelvic tone disorders in 31 cases. Urodynamic studies, performed in 113 patients, demonstrated sphincter incompetence in 65 cases (57.5%) with a mean maximum urethral closure pressure of 18 cmH2O (range: 5-29). RESULTS: The operation, performed under spinal anaesthesia in 97 cases (80.8%), general anaesthesia in 16 cases (13.3%) and local anaesthesia in 7 cases (5.8%) lasted an average of 28.7 min (range: 15-60) for insertion of the TVT. Perioperative complications consisted of twelve bladder injuries (10%) and two pelvic haematomas (1.7%). No cases of infection, erosion or migration of the tape were reported. In the group of 94 patients operated exclusively by TVT, the mean hospital stay was 2.6 days (range: 1-7). Twelve patients (10%) required self-catheterization for 2 to 30 days. With a mean follow-up of 15.2 months (range: 36-6), continence was restored in 104 patients, corresponding to a cure rate of 86.7%. A marked improvement was obtained in 11 cases (9.2%) and five cases (4.2%) were considered to be failures. CONCLUSION: The TVT procedure is a new approach to the treatment of female urinary stress incontinence. Its advantages are its simplicity, the rapidity of the technical procedure and the short-term efficacy on continence. A longer follow-up is essential to assess to the functional outcome and the long-term urethral tolerance.

[Percutaneous endopyelotomies. Preliminary results (a series of 16 patients)]. / Endopyélotomies percutanées. Résultats préliminaires (à propos d'une série de 16 malades).

Percutaneous endopyelotomy was performed in 16 patients with ureteropelvic junction obstruction. The procedure was always completed with no intra-operative complication. After a mean follow-up of 18 months (6-30 mos), we report 12 good results (75%), 2 patients with no clinical symptoms but remaining partial radiological obstruction, and 2 failures (12.5%) which required early open surgery. Much care must be given to the ureteral stenting: one of our failures was due to extra-pelvic migration of the stent. Endopyelotomy may be considered as an efficient procedure, but long-term evaluation is still required.