Beneficiation Studies on Cobalt Bearing Ore from Africa

Cobalt bearing ore is used in Africa for hydro-metallurg-ical extraction of Co. The party desired to know whether it is possible to pre-concentrate this ore in order to reduce the material handled by metallurgical operations. This cobalt bearing sample (5% Co) was beneficiated in the Modern Mineral Processing Laboratory and Pilot Plant of Indian Bureau of Mines at Nagpur. The cobalt was ident-ified by EPMA to be present as WAD where manganese is replaced by cobalt. The as-received sample was dominated by fines. Screening the as received sample on 10 mesh followed by desliming of -10 mesh fraction yielded a Co concentrate assaying 7.2% Co with 94.6% cobalt recovery. Although the concentrate assays only 7.2% Co, this simple process developed offers the advantage that around 33% of the slimes (<20 microns in size assaying around I% Co) can bypass the metallurgical operations to follow thus drast-ically reducing the handling, settling and filtration problems in the extraction of Co by hydrometallurgical route with minimum Co losses in the tailings

A study of empyema thoracis and role of intrapleural streptokinase in its management

BACKGROUND: Clinical spectrum, microbiology and outcome of empyema thoracis are changing. Intrapleural instillation of fibrinolytic agents is being increasingly used for management of empyema thoracis. The present study was carried out to describe the clinical profile and outcome of patients with empyema thoracis including those with chronic empyema and to study the efficacy and safety of intrapleural streptokinase in its management. METHODS: Clinical profile, etiological agents, hospital course and outcome of 31 patients (mean age 40 ± 16 years, M: F 25: 6) with empyema thoracis treated from 1998 to 2003 was analyzed. All patients were diagnosed on the basis of aspiration of frank pus from pleural cavity. Clinical profile, response to therapy and outcome were compared between the patients who received intrapleural streptokinase (n = 12) and those who did not (n = 19). RESULTS: Etiology was tubercular in 42% of the patients (n = 13) whereas the rest were bacterial. Amongst the patients in which organisms could be isolated (n = 13, 42%) Staphylococcus aureus was the commonest (n = 5). Intrapleural streptokinase was instilled in 12 patients. This procedure resulted in increase of drainage of pleural fluid in all patients. Mean daily pleural fluid drainage after streptokinase instillation was significantly higher for patients who received intrapleural streptokinase than those who did not (213 ml vs 57 ml, p = 0.006). Only one patient who was instilled streptokinase eventually required decortication, which had to be done in five patients (16.1%). Mean hospital stay was 30.2 ± 17.6 days whereas two patients died. CONCLUSIONS: Tubercular empyema is common in Indian patients. Intrapleural streptokinase appears to be a useful strategy to preserve lung function and reduce need for surgery in patients with late stage of empyema thoracis

Induction of death receptor 5 expression in tumor vasculature by perifosine restores the vascular disruption activity of TRAIL-expressing CD34+ cells

The proapoptotic death receptor 5 (DR5) expressed by tumor associated endothelial cells (TECs) mediates vascular disrupting effects of human CD34 + cells engineered to express membrane-bound tumor necrosis factor-related apoptosis-inducing ligand (CD34-TRAIL + cells) in mice. Indeed, lack of DR5 on TECs causes resistance to CD34-TRAIL + cells. By xenografting in nonobese diabetic/severe combined immunodeficient mice the TRAIL-resistant lymphoma cell line SU-DHL-4V, which generates tumors lacking endothelial DR5 expression, here we demonstrate for the first time that the Akt inhibitor perifosine induces in vivo DR5 expression on TECs, thereby overcoming tumor resistance to the vascular disruption activity of CD34-TRAIL + cells. In fact, CD34-TRAIL + cells combined with perifosine, but not CD34-TRAIL + cells alone, exerted marked antivascular effects and caused a threefold increase of hemorrhagic necrosis in SU-DHL-4V tumors. Consistent with lack of DR5 expression, CD34-TRAIL + cells failed to affect the growth of SU-DHL-4V tumors, but CD34-TRAIL + cells plus perifosine reduced tumor volumes by 60 % compared with controls. In view of future clinical studies using membrane-bound TRAIL, our results highlight a strategy to rescue patients with primary or acquired resistance due to the lack of DR5 expression in tumor vasculature