Entropic self-assembly of freely rotating polyhedral particles confined to a flat interface.

The self-assembly of hard polyhedral particles confined to a flat interface is studied using Monte Carlo simulations. The particles are pinned to the interface by restricting their movement in the direction perpendicular to it while allowing their free rotations. The six different polyhedral shapes studied in this work are selected from a family of truncated cubes defined by a truncation parameter, s, which varies from cubes (s = 0) via cuboctahedra (s = 0.5) to octahedra (s = 1). Our results suggest that shapes with small values of s show square-like behavior whereas shapes with large values of s tend to show more disc-like behavior. At an intermediate value of s = 0.4, the phase behavior of the system shows both square-like and disc-like features. The results are also compared with the phase behavior of 3D bulk polyhedra and of 2D rounded hard squares. Both comparisons reveal key similarities in the number and sequence of mesophases and solid phases observed. These insights on 2D entropic self-assembly of polyhedral particles is a first step toward understanding the self-assembly of particles at fluid-fluid interfaces, which is driven by a complex interplay of entropic and enthalpic forces. A first-order analysis of the particle-surface energies associated with a fluid-fluid interface indicates that such enthalpic interactions will be particularly important in determining particle orientation behavior at low to intermediate concentrations.

Isolated breast mucormycosis.

Mucormycosis is unusual in surgical practice. Awareness of the classical findings leads to early detection. Excisional therapy whenever possible along with systemic antifungal treatment is the key to successful outcome. A 70 year old female, a known case of diabetes mellitus and chronic obstructive pulmonary disease, on inhalational steroids and oral hypoglycemic agents, presented to us with complaints of sudden onset pain, redness and swelling of left breast. A diagnosis of severe mastitis was made and a release incision was taken. The entire breast became gangrenous in next 24 hours and simple mastectomy had to be performed as a life saving measure. Histopathology revealed mucormycosis of breast. To the best of our knowledge this is the first reported case of mucormycosis of breast in the English literature.

Giant renal capsular leiomyoma: study of two cases.

Leiomyomas of the renal parenchyma and of the capsule are rare. These tumours are normally small asymptomatic and often detected incidentally. Large renal leiomyomas can present with pain or as an abdominal mass, but they are rare. The imaging features of these tumours have been poorly described in the literature. A radiological distinction from other renal neoplasms is often difficult to make owing to the similarity of imaging findings. We report two patients with renal leiomyomas who presented with pain and an abdominal mass. Both patients underwent nephrectomy and histological evaluation confirmed the diagnosis of leiomyoma.

Brain abscess following esophageal dilatation.

The authors report a case of brain abscess following esophageal dilatation for corrosive stricture in a 23-year-old woman. High fever and neurological findings post dilatation led us to suspect this rare complication, which was confirmed by cranial computed tomography. Prompt treatment with antibiotics and surgical drainage led to a favorable clinical outcome. This serious complication should be kept in mind when long-term treatment of corrosive stricture by repeated esophageal dilatation is planned. Prior cases of brain abscess following esophageal dilatation are reviewed.

Isolated splenic lymphoma: an elusive preoperative diagnosis.

Four patients underwent splenectomy for various clinical and radiological diagnoses and were found to have primary splenic lymphoma at surgery and histology. The diagnosis was classical Hodgkin's lymphoma, mixed cellularity type (one case); marginal zone B-cell non-Hodgkin's lymphoma (one case); and large B cell type non-Hodgkin's lymphoma (two cases). The first two patients had multiple nodules in the spleen measuring 0.1-0.5 cm while large cell lymphomas had large nodules (largest measuring 11 cm x 7 cm x 4 cm). The diagnoses were confirmed by immunohistochemical analysis. Mean follow up of these patients was 11 months; all patients received chemotherapy. One patient died, of causes not related to the disease process.

Giant prosthesis for reinforcement of visceral sac for complex bilateral and recurrent inguinal hernias: a prospective evaluation.

AIMS: To evaluate giant prosthesis for reinforcement of visceral sac (GPRVS) as a treatment for complex bilateral and recurrent inguinal hernias. SUBJECTS AND METHODS: The prospective study carried out in a single surgical unit at a tertiary health care center involved consecutive series of 31 patients with complex bilateral and recurrent inguinal hernias who underwent GPRVS. All were men and the mean age was 58 years (range 49-95 years). Factors predicting high risk for recurrence included a large hernia ( greater, similar5cms, 32%, 10/31 patients), failure of one or more previous repairs (45%, 14/31 patients), chronic obstructive pulmonary disease (25%, 8/31 patients) and poor muscle tone (70%, 22/31 patients). Operative time, length of postoperative stay, complications and death were the main outcome measures. RESULTS: Mean -/+ SEM operative time was 65 -/+ 11 minutes (range 45-115 minutes). Mean -/+ SEM length of stay was 3.5 -/+ 0.7 days (range 2-5 days). There were 4 minor complications, but no mesh infections and death. Follow up was obtained for a mean period of 14.6 months (range 12-23 months); there were no recurrences. CONCLUSION: GPRVS provides a definitive and safe cure for repair of complex bilateral and recurrent inguinal hernias because of its simplicity, ease of the procedure, good results and low recurrence rate.

Paraesophageal mediastinal drainage with diversion for delayed presentation of esophageal perforation.

Esophageal perforation is a serious condition; a delay of more than 48 hours in initiation of treatment leads to increased morbidity and mortality. Management of such patients is a surgical dilemma. We successfully managed 4 patients (2-iatrogenic, 1-tuberculous, 1-Boerhaave's syndrome) with delayed presentation of esophageal perforation by esophageal exclusion and paraesophageal mediastinal drainage, achieving good control of mediastinal sepsis, healing of perforation and at the same time avoiding thoracotomy and subsequent second surgery.

Shouldice's herniorrhaphy versus Moloney's darn herniorrhaphy in young patients (a prospective randomised study).

AIMS: Shouldice's repair (SR) and Moloney's darn repair (DR) are commonly practised repairs for hernias in the young age group with acceptably low recurrence rates. The SR is considered technically challenging and difficult, while the DR is gaining popularity in recent years. Therefore, there is a need to compare these repairs. MATERIAL AND METHODS: To compare these techniques a total of 50 cases (age group 18-40 years) were randomised to two groups (SR 25, DR 25). These were well matched for age, the side and the type of hernia. Both groups were studied with respect to operative time; postoperative pain at 6,12 and 24 hours (evaluated by pain scale 1-10) need for analgesia, ambulation (evaluated by a four-point scale), complications and return to work. RESULTS: The SR required a longer time (average 81 minutes) compared to DR (average 43 minutes). Patients undergoing SR complained of pain of a higher scale at 6, 12 and 24 hours post surgery and had a significant higher need for analgesia on day 1 and 2 (p < 0.05). Ambulation grades were significantly better in the DR group on the first postoperative day (p < 0.05). There was no significant difference in the two groups with respect to postoperative complications, return to work, and recurrences rate (2-year follow-up). CONCLUSION: The SR and DR are comparable for young patients having a primary hernia. However, DR is superior in terms of the time taken, post-operative pain, need for analgesia and early ambulation.

Spontaneous oesophageal perforation due to mediastinal tuberculous lymphadenitis - atypical presentation of tuberculosis.

Spontaneous non-traumatic oesophageal perforation secondary to bursting of a mediastinal tuberculous abscess into the oesophagus is rare. The diagnosis is delayed, as perforation remains localised due to mediastinal lymph nodes. Patient can be effectively managed by paraoesophageal drainage of the mediastinal abscess and oesophageal diversion.

Synchronous primary adenocarcinoma of small and large bowel.

Synchronous cancer of the small and large bowel is rare. We report a 45-year-old woman with synchronous primary cancer of the jejunum and descending colon who presented with intestinal obstruction.