Bounding film drainage in common thin films

A review of thin film drainage models is presented in which the predictions of thinning velocities and drainage times are compared to reported values on foam and emulsion films found in the literature. Free standing films with tangentially immobile interfaces and suppressed electrostatic repulsion are considered, such as those studied in capillary cells. The experimental thinning velocities and drainage times of foams and emulsions are shown to be bounded by predictions from the Reynolds and the theoretical MTsR equations. The semi-empirical MTsR and the surface wave equations were the most consistently accurate with all of the films considered. These results are used in an accompanying paper to develop scaling laws that bound the critical film thickness of foam and emulsion films. (c) 2005 Elsevier B.V. All rights reserved.

Clinical features and management of tumors affecting the lacrimal drainage apparatus

Purpose: To report the clinical features of a series of patients with lacrimal drainage apparatus tumors and present guidelines for management based on histopathology. Methods: A noncomparative retrospective chart review of the clinical, imaging, and pathologic findings of 37 patients presenting to four regional orbital Surgery departments with tumors affecting the lacrimal drainage apparatus between 1990 and 2004. Results: There were 37 patients, of whom 62% were male. The mean age at referral was 54 years. Epiphora, a palpable mass, and dacryocystitis were the most common presentations. Two thirds of the tumors were epithelial. with carcinomas being the most frequent (38%). followed by papillomas (27%). Lymphomas were the most common nonepithelial malignancy (30%). Epithelial tumors were more common in men (87%), whereas lymphomas were more common in women (57%). Treatment modalities included surgery, in addition to radiotherapy and/or chemotherapy and immunotherapy. Mean follow-up was 38 months. Thirty-three patients (89%) remain alive without evidence of disease and 4 patients died of recurrence and/or metastases. Conclusions: Lacrimal drainage apparatus tumors require careful initial management to ensure adequate local and systemic disease control. Atypical mucosa encountered during dacryocystorhinostomy should be biopsied and small papillomas or pedunculated tumors excised and analyzed with frozen sections. If a diffuse or infiltrative mass is encountered, it should be biopsied and managed on the basis of histopathology and extent of disease. Lymphomas should be treated according to protocols. whereas noninvasive carcinoma and extensive papillomas require complete excision of the system. Invasive disease requires en bloc excision. Long-term follow-up is essential for early detection of recurrence.

En bloc excision in malignant tumors of the lacrimal drainage apparatus

Purpose: To describe the surgical technique and results of en bloc excision in a series of patients with extensive malignant tumors of the lacrimal drainage apparatus (LDA). Methods: This was a noncomparative, retrospective chart review of the clinical and pathologic findings of 11 patients presenting with a malignant tumor affecting the LDA who underwent en bloc excision of the lacrimal system. Results: Of the 11 patients, 7 were male. The mean age at presentation was 58 years (range, 39 to 81 years), and all cases were unilateral. Histopathology revealed 4 squamous cell carcinomas, 3 transitional cell carcinomas, 2 mucoepidermoid carcinomas, and 2 melanomas. Epiphora and a mass were the most common presentations. An external lesion could be identified in 4 cases. Irrigation of the lacrimal system revealed nasolacrimal duct obstruction in 2 cases and common canaliculus obstruction in another 2 patients. The entire LDA and surrounding bony tissues were excised through a lateral rhinotomy approach. Adjuvant radiotherapy was given in 4 cases. Nine patients remain alive and well after a mean follow-up of 2 years (range, 6 months to 7 years). Three cases showed distant disease and 2 patients died of metastatic melanoma involvement. Conclusions: The use of en bloc excision as a radical treatment to remove the complete LDA and surrounding bony structures affords good local tumor control and may provide the best opportunity for enhanced patient survival.

Aquatic invertebrates in final void water bodies at an open-cut coal mine in central Queensland

We describe the diversity of aquatic invertebrates colonising water-filled final voids produced by an open-cut coal mine near Moura, central Queensland. Ten disused pits that had been filled with water from < 1 year to 22 years prior to the survey and three nearby 'natural' water bodies were sampled in December 1998 and again in March 1999. All invertebrates collected were identified to family with the exception of oligochaetes, cladocerans, ostracods and copepods, which were identified to these coarser taxonomic levels. Sixty-two taxa were recorded from > 20 000 individuals. The greatest familial richness was displayed by the Insecta (33 families) followed by the mites (Acari) with 12 families. While natural water bodies held the greatest diversity, several mine pits were almost as rich in families. Classification analyses showed that natural sites tended to cluster together, but the groupings did not clearly exclude pit sites. Mining pits that supported higher diversity tended to be older and had lower salinity (< 2000 mu S/cm); however, salinity in all water bodies varied with rainfall conditions. We conclude that ponds formed in final voids at this mine have the potential to provide habitat for many invertebrate taxa typical of lentic inland water bodies in central Queensland.

Combined external-endonasal approach for complete excision of the lacrimal drainage apparatus

Purpose: The purpose of this study was to describe a new surgical technique for the complete excision of the lacrimal drainage apparatus (LDA) that combines external and endoscopic approaches. Methods: This study involved a noncomparative, retrospective chart review of the clinical and pathological findings of four patients presenting with LDA papillomas who underwent a combined open and endonasal excision of the lacrimal system. Results. Of the four patients, three were male. The mean age at referral was 41 years, and all cases were unilateral. Histopathology revealed two transitional cell papillomas, one squamous cell papilloma, and one combined transitional/squamous papilloma. Epiphora and an external lesion were the main complaints at presentation. Nasolacrimal duct obstruction was present in all four patients. Papilloma virus infection was suggested in two cases and was confirmed in the only patient who had recurrence. CT identified a solid enhancing mass in two cases. The surgical approach in all cases was performed with the patient under general anesthetic supplemented with infiltration of local anesthesia with vasoconstriction. The lacrimal sac was exposed as per an external dacryocystorhinostomy with biopsy collection from the lacrimal sac lumen to confirm the diagnosis prior LDA excision. The superior aspect of the LDA was isolated by using lacrimal probes in each canaliculus to stabilized parallel incisions and careful dissection toward the common canaliculus until they met the medial aspect of the lacrimal sac. The sac was then separated from the periosteum from the medial orbital wall, using sharp dissection. Finally, an endoscopic dissection of the lower end of the nasolacrimal duct released the most inferior aspect of the LDA, allowing the surgeon to pull and excise the complete system from the external wound. Conclusions: Extensive LDA papillomas required complete excision of the drainage system to prevent recurrence and/or malignant transformation. The use of a combined approach through an open excision of the superior part of the LDA in conjunction with the direct manipulation of the nasolacrimal duct guided by the nasal endoscope facilitates the complete excision of the system for extensive benign lesions.

A numerical study of steady state evaporative conditions applied to mine tailings

The suction profile of a desiccating soil is dependent on the water table depth, the soil-water retention characteristics, and the climatic conditions. In this paper, an unsaturated flow model, which simulates both liquid and vapour flow, was used to investigate the effects of varying the water table depth and the evaporation rate on the evaporative fluxes from a desiccating tailings deposit under steady-state conditions. Results obtained showed that at a critical evaporation rate, beyond which evaporation is no longer dictated by climatic conditions, the matric suction profiles remain basically unchanged. The critical evaporation rate varies inversely with the water table depth. It is associated with the maximum evaporative flux that might be extracted from a soil at steady-state conditions. The time required to establish steady-state conditions is directly proportional to the water table depth, and it acquires a maximum value at the critical evaporation rate. A detailed investigation of the movement of the drying front demonstrated the significance of attaining a matric suction of about 3000 kPa on the contribution to flow in the vapour phase.