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Alessandro Silva

Publications and source records attributed to Alessandro Silva.

3 recordsLinked to original sources

Instanton analysis of hysteresis in the three-dimensional random-field Ising model.

We study the magnetic hysteresis in the random-field Ising model in 3D. We discuss the disorder dependence of the coercive field Hc, and obtain an analytical description of the smooth part of the hysteresis below and above Hc, by identifying the disorder configurations (instantons) that are the most probable to trigger local avalanches. We estimate the critical disorder strength at which the hysteresis curve becomes continuous. From an instanton analysis at zero field we obtain a description of local two-level systems in the ferromagnetic phase.

Journal Article↗

The incidence of postoperative wound healing problems following sagittal ramus osteotomies stabilized with miniplates and monocortical screws.

PURPOSE: Titanium plates and monocortical screws are commonly used to stabilize the mandible following sagittal split ramus osteotomies. Despite widespread use of this type of fixation, there is a paucity of large studies evaluating the infection rate and need for hardware removal. MATERIALS AND METHODS: This study is a retrospective cohort evaluation of 1,066 consecutive mandibular sagittal ramus osteotomies in 533 patients, performed between January 2002 and December 2003. All osteotomies were stabilized with 4-hole miniplates and 2.0 mm x 5.0 mm monocortical screws. Study variables included disturbances of wound healing, age, gender, plate and screw position, direction of mandibular movement, adjunctive procedures performed, and the patient's medical history. Data were collected by chart and radiographic review. The above variables were analyzed using Fisher's exact test, Chi-square, Cochran-Armitage Trend Test, and multiple logistic regression. RESULTS: Of 533 patients 26% (138) demonstrated wound healing problems. This occurred in 15% of all 1,066 osteotomy sites. 6.5% of plates required removal in 10% of patients. In no case did disturbance of wound healing or plate removal result in non-union or relapse of the osteotomy. Wound healing problems were fewer when mandibular osteotomies were done in conjunction with maxillary surgery (18.9% versus 29.1%). Disturbances of wound healing were not related to the direction of movement of the mandible and were lower when hardware was placed closer to the inferior border. CONCLUSION: An overall low incidence (6.5%) of hardware infection requiring plate removal was found in this study. Screw proximity to the osteotomy site did not correlate with higher rates of healing problems, but there was a statistically significant trend of fewer disturbances of healing when the hardware was placed closer to the inferior border of the mandible.

Adolescent↗