Removal of copper from a copper sulphate solution using an ultrasonic-electrolysis process.

The application of ultrasonic-electrolysis process for the removal of copper is studied. In the ultrasonic field cavitation acts as jets and agitates the solution and breaks the barrier layer between the cathode surface and the bulk of the solution. Thus increases metal deposition on the cathode surface. The results show that an ultrasonic field is successful for the removal of low copper concentrations in solution.

Simultaneous recovery of copper and degradation of 2,4-dichlorophenoxyacetic acid in aqueous systems by a combination of electrolytic and photolytic processes.

In mixed industrial effluent the presence of metal ions can retard the destruction of organic contaminants and the efficiency of recovery of the metal is reduced by the presence of the organic species. Results are presented for copper-2,4-dichlorophenoxyacetic acid (2,4-D) system in which both effects occur. An electrochemical cell alone can be used to recover copper in the pH range 1.5-4.5 but it is not capable of achieving complete disappearance of 2,4-D by anodic oxidation. A photolytic cell alone can achieve the destruction of 2,4-D at pH 3.5 but leaves copper in solution. A combined photolytic-electrochemical system using an activated carbon concentrator cathode achieves the rapid simultaneous destruction of 2,4-D and recovery of copper. Results are presented for the recovery of more than 90% copper from, and >99.9%, destruction of the organochlorine compound 2,4-D in, a solution containing 100 mg dm(-3) copper and 50 mg dm(-3) 2.4-D. The photolytic degradation of 2,4-D depends on the intensity of the UV-probe. Only 19% degradation is achieved after 8 h with the 150 W UV-probe but the corresponding value with the 400 W UV-probe is 100%. In the case of 150 W UV-probe the degradation of 2,4-D proceeds through the formation of 2,4-dichlorophenol and phenol. The concentration of these intermediates are very low in the case of 400 W UV-probe because the speed of the degradation of 2,4-D is very fast. The addition of TiO2 (1 g dm(-3)), as a semiconductor material, and H202 (1.5 g dm(-3)) as an oxidant, increases the photolytic degradation of 2,4-D.

Interstitial brachytherapy in carcinoma of the penis.

AIM: Keeping in line with the increasing emphasis on organ preservation, we at the Tata Memorial Hospital have evaluated the role of Ir-192 interstitial implant as regards local control, functional and cosmetic outcome in early as well as locally recurrent carcinoma of the distal penis. PATIENTS AND METHODS: From October 1988 to December 1996, 23 patients with histopathologically proven cancer of the penis were treated with radical radiation therapy using Ir-192 temporary interstitial implant. Our patients were in the age group of 20 to 60 years. The primary lesions were T1 in 7, T2 in 7 and recurrent in 9 patients. Only 7 patients had palpable groin nodes at presentation, all of which were pathologically negative. The median dose of implant was 50 Gy (range 40 to 60 Gy), using the LDR afterloading system and the Paris system of implant rules for dosimetry. Follow-up ranged from 4 to 117 months (median 24 months). RESULTS: At last follow-up 18 of the 23 patients remained locally controlled with implant alone. Three patients failed only locally, 2 locoregionally and 1 only at the groin. Of the 5 patients who failed locally, 4 were successfully salvaged with partial penectomy and remained controlled when last seen. Local control with implant alone at 8 years was 70% by life table analysis. The patients had excellent functional and cosmetic outcome. We did not record any case of skin or soft-tissue necrosis. Only 2 patients developed meatal stenosis, both of which were treated endoscopically. CONCLUSION: Our results lead us to interpret that interstitial brachytherapy with Ir-192 offers excellent local control rates with preservation of organ and function. Penectomy can be reserved as a means for effective salvage.

Interstitial brachytherapy in soft tissue sarcomas. The Tata Memorial Hospital experience.

BACKGROUND: Soft tissue sarcomas are relatively rare tumors with an aggressive natural history associated with a high propensity for local recurrence following conservative surgery. It accounts for 1.8% of all cancers seen at the Tata Memorial Hospital, Mumbai. Organ preserving surgery and tumor bed brachytherapy have revolutionized the management of soft tissue sarcomas. PATIENTS AND METHODS: One hundred and seventy-seven patients with histologically proven non-metastatic cases of soft tissue sarcomas in the age group of 16 to 79 years (median 41 years) were treated at the Tata Memorial Hospital between January 1983 and December 1992. One hundred and fifty-one patients who had completed a minimum of 24 months of treatment were studied. There were 100 males (66%) and 51 females (33%). The majority had recurrent lesions (70.3%). Extremities were involved in 75% of patients. Spindle cell sarcoma was the major histologic variant (30%). The patients underwent function preserving surgery and temporary afterloading Ir-192 tumor bed brachytherapy with or without external radiotherapy. RESULTS: In patients receiving brachytherapy only, 25 out of 33 (75%) were locally controlled after a median follow-up of 30 months. After successful salvage of local failures the overall local control improved to 82%. Similarly in the patients who received both interstitial brachytherapy and external irradiation, the local control rate after a median follow-up of 40 months was 71% which improved to 86% after successful salvage. The overall treatment related complication rate was less than 1%. The only marginally significant prognostic factor for local control was tumor grade (p = 0.06). CONCLUSIONS: The sequential combination of limited surgery and tumor bed brachytherapy with or without external radiotherapy has been established as an effective alternative to more ablative procedures like amputation. Histologic grade has proven to be a significant factor determining local control.

Radiotherapy of carcinoma of the buccal mucosa.

A retrospective study of 399 cases of buccal cancer, presenting to the Tata Memorial Hospital, Bombay, during January to December 1984 was undertaken to define the efficacy of various treatment modalities in different clinical stages. Analysis of treatment technique and response was carried out in 185 cases that completed adequate therapy. Sixty percent of patients with stage I and II disease (21/35) received radiation therapy alone as the primary modality of treatment. Patients (150) with stage III or IV disease received palliative irradiation (57 cases), radical surgery (54 cases), or a combination of both (39 cases). The 2-year disease-free survival (DFS) rates were 48% for radiotherapy and 46% for surgery in the early stages and 5% and 33%, respectively, for advanced stages. Radiotherapy with a modified technique is recommended for the early-stage cancers and preoperative irradiation with adjuvant chemotherapy or hyperthermia for the advanced stages.