Possible origin of the smaller-than-universal percolation-conductivity exponent in the continuum.

For quite a few systems in the continuum, such as carbon nanotube polymer composites and segregated composites, percolation electrical conductivity exponents that are much smaller than the universal value have been reported. This is unexpected in view of the classical lattice percolation theory. Here we provide a simple general phenomenological model that accounts for such observations within the framework of universality. We suggest that these small value exponents are due to the interplay between the connectivity and the structural variations that follow the increase of the fractional volume content of the conducting phase.

Tibial rotational osteotomy and distal tuberosity transfer for patella subluxation secondary to excessive external tibial torsion: surgical technique and clinical outcome.

PURPOSE: Recurrent patella subluxation may be secondary to excessive external tibial torsion. The purpose of this study is to evaluate the clinical and radiographic outcome of patients undergoing tibial derotation osteotomy and tibial tuberosity transfer for recurrent patella subluxation in association with excessive external tibial torsion. METHODS: A combined tibial derotation osteotomy and tibial tuberosity transfer was performed in 15 knees (12 patients) with recurrent patella subluxation secondary to excessive external tibial torsion. Clinical evaluation was carried out using preoperative and post-operative Knee Society Score (KSS), Kujala Patellofemoral score, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire, the short form-12 (SF-12) and a visual analogue score (VAS) pain scale. RESULTS: The median follow-up period was 84 months (range 15-156) and median patient age was 34 years (range 19-57 years). The median preoperative external tibial torsion was 62° (range 55°-70°), with a median rotational correction of 36° (range 30°-45°) after surgery. Significant improvement (p < 0.05) was found in the KSS part I (37 ± 14 to 89 ± 11 points), KSS part II (25 ± 26 to 85 ± 14 points), Kujala score, the SF-12 outcome, WOMAC score and VAS score (8.8 ± 1.9 to 2.4 ± 1.5). Two patients had a nonunion of the tibial osteotomy site; one patient required bone grafting, while another patient required revision to total knee arthroplasty. CONCLUSION: Patients presenting with recurrent patella subluxation secondary to excessive external tibial torsion >45° who underwent tibial derotation osteotomy and tibial tuberosity transfer achieved a satisfactory outcome in terms of pain relief and improved function. A significant complication was seen in 2/15 patients. LEVEL OF EVIDENCE: Case series, Level IV.

[Effect of polypectomy on voice quality].

Voice quality and improvement after vocal cord polypectomy was assessed in 15 patients. The polyps were found by indirect observation; assessment of vocal quality was by recording isolated vowels, words and sentences said in Hebrew before operation and 1 and 3 months later. The recordings were analyzed using a computer program written at the Medical Electronics Laboratory of The Technion. Analysis of the 5 Hebrew vowels (a,e,i,o,u) yielded numerical and graphical data of formats specific for each utterance and speaker. These data were compared with control data taken from the literature for healthy Hebrew speakers. Statistical analysis (by paired t-test for matched samples) revealed a tendency to a decrease in difference between postoperative results and control data. Comparison of preoperative recordings with control data suggest that this method of voice condition assessment is worth considering for systematic application in clinics and hospitals. Among its advantages is that it permits long-term objective assessment of changes in voice quality. It thus supplies data for follow-up studies of patients and others who suffer from voice problems, especially those whose voice is their professional tool.

Bilateral perilymph fistula in an adult.

Sudden hearing loss is a symptom caused by a variety of diseases, among them also a perilymph fistula. The occurrence of bilateral perilymph fistula is rare, and was reported only associated with head trauma. A case of a bilateral perilymph fistula, without head trauma in an adult construction worker is reported. To the best of our knowledge this is the first bilateral case caused by physical effort to be reported in the literature.

Model studies of the effects of the thoracic pressure on the circulation.

Two models of the cardiovascular system subjected to changes in intrathoracic pressure (ITP) are used to simulate the response to normal and positive pressure ventilation and the Mueller maneuver. The first model, based on our earlier model for cardiopulmonary resuscitation and cardiac assist by ITP variations, is based on lumped parameter representation of the cardiovascular system with two ventricles which function based on the time-varying elastance concept using their transmural pressures as the load. The ITP is assumed to be equally distributed in the thoracic cavity and equally affecting all cardiovascular structures within the chest. The model shows that a decrease in ITP is associated with an initial decrease in aortic pressure and flow and an increase in left ventricular end-diastolic and end-systolic volumes. A transient decrease in left ventricular volume which was suggested to occur by a few studies cannot be predicted based on this model. Such a decrease in left ventricular volume can be only predicted when a pericardial constraint is included, as done in the second model. Positive pressure interventions are associated with decreased heart volumes and cardiac output which is primarily a "preload" effect. In general the model reasonably predicts the hemodynamics as a function of the ITP changes and may be used as a tool to investigate the response of the cardiovascular system to various ITP interventions.

Sexual problems among family medicine patients.

A self-administered questionnaire assessing sexual satisfaction and presence of a number of common sexual problems was developed. Following assessment of reliability and validity, the questionnaire was administered to 142 patients seen in a family medicine center. While 56 percent of patients reported one or more sexual problems, such problems were noted in the medical record in 22 percent of the cases. The nature of many of the problems (ie, techniques of foreplay, fear of pregnancy, and differences in attitudes and expectations between partners) suggests an effective role in treatment for the primary care physician.

Functional disability of elderly family medicine patients in acute care hospital and nursing homes.

This report describes the functional impairments of elderly patients from a family medicine program who were admitted either to an acute care hospital or long-term care facilities over the course of a year. Assessments were performed in the areas of social and economic resources, mental health, physical health, and the ability to perform routine activities needed for independent living. The presence of significant functional impairment in many of the areas suggests the need for the family physician to develop skills in working as a member of a health care team in order to design and implement a comprehensive treatment plan for elderly patients admitted either to hospitals or long-term care facilities.