Characterization of Rampura-Agucha Lead-Zinc Ore using Electron Probe Micro Analyzer (EPMA) in View of Beneficiation

Beneficiation test work on a Pb-Zn sample from Rampura-Agucha mines was taken up with a view to (i) explore the possibility of reducing the Zn losses in tailings from the present level of 2.4% to as low as possible, (ii) assess the reason for low grade Zn and Pb concentrates presently produced in the plant and (iii) evaluate the reason for very low Pb recovery values. This paper highlights the significant role played by Electron Probe Micro Analyzer (EPMA) in understanding the textural and compositional features of various minerals prior to the beneficiation test work and also in suggesting necessary alterations in the process parameters whilst mineral processing studies are underwa

Rapid Determination of Mg, Fe, Al, etc., in Rock Phosphate Samples using Atomic Absorption Spectrophotometer

There are several methods for the determination of Mg, Fe, Al and other elements in phosphorite samples. The method of analysis is developed in chemical laboratory of RODL, IBM, Bangalore for rock phosphate sample which is not only very fast and accurate but also maximum number of required elements can be analysed in the prepared solution. This method was used for the analysis of ore dressing products obtained while carrying out the beneficiation studies on rock phosphate samples from China. The sample is treated with aquaregia followed by perchl-oric acid. The prepared solution is used for the determina-tion of maximum number of elements like Mg, Fe, Al etc., by Atomic Absorption Spectrophotometer. By taking suitable aliquot from the solution, P205 can be analysed by volu-metric or gravimetric method. Residue is used for the determination of Si02

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

Beneficiation Practices in the Sukinda Valley Area Chromite Deposits

Extensive Chromite deposits in sukinda valley occur between District Jajpur and Keonjhar, Orissa. Mostly the ores are granular fines with a few soft moist and friable lumpy masses. In these lumps chromite grains occur as discrete grains within ferruginous matrix. In few cases serpentine and quartz association are also observed. The inherent characteristics of the deposits are such that their up-gradation / value addition does not pose many problems to the natives of the area. The method of benefi-ciation ranges from primitive Stone Age to modern-day technology. Consequent upon quantity c eiling on export of high grade chromite ore (ROM) and no such restriction on chromite concentrate in the country, mushrooming of chro-mite ore beneficiation (COB) facilities took place in the leasehold sectors and also outside of it. This resulted in unscrupulous exploitation by a few equipment manufactu-rers, suppliers & consultants engaged for commissioning of COB facilities without a proper development of process flow sheet and metallurgical accounting. Such procurement of machinery / equipment though enhanced the throughput capacity of concentrate generation but compromised on the recovery of valuables, especially fines. Such unscientific value addition of the ROM ore jeopardized the very concept of conservation. This paper deals with the processing technology being prac-ticed in the Sukinda valley for the friable chromite ore, and the remedial measure needed for optimum recovery of the valuables established through extensive R&D work done at IBM laboratory

Mineralogical and Electron Microprobe Studies on the Cobalt Sample from Kalyadi Copper Deposit, Hassan District, Karnataka

The copper-cobalt deposit from Kalyadi, Hassan district is located between Sigegudda and Nuggihalli greenstone belts of Karnataka Craton. The cobalt mineralisation is mostly in banded, cherty and feldspathoid quartzite. The cobalt sample under investigation has been characterized by a variety of techniques including electron microprobe studies. The microprobe studies on sulphide grains were done to study the chemistry and elemental replacement in their lattice structure. The cobalt is present up to 3.21 wt% in pyrite grains whereas it is not present in chalco-pyrite and arsenopyrite. Cobalt has preferably replaced iron in pyrite, which is of volcanic - exhalative origin

HYDROGEN SULFIDE THERAPY ATTENUATES ISCHEMIA-INDUCED HEART FAILURE VIA NRF2 AND NRF1 SIGNALING

Codi d'Art Públic: 9008-1 (Cavalls desbocats)Ros Sabaté, Joaquim (Escultura); Batlle, Enric; Roig, Joa

Two step activation of FOXO3 by AMPK generates a coherent feed-forward loop determining excitotoxic cell fate

Cerebral ischemia and excitotoxic injury induce transient or permanent bioenergetic failure, and may result in neuronal apoptosis or necrosis. We have previously shown that ATP depletion and activation of AMP-activated protein kinase (AMPK) during excitotoxic injury induces neuronal apoptosis by transcription of the proapoptotic BH3 only protein, Bim. AMPK, however, also exerts pro-survival functions in neurons. The molecular switches that determine these differential outcomes are not well understood. Using an approach combining biochemistry, single cell imaging and computational modeling, we here demonstrate that excitotoxic injury activated the bim promoter in a FOXO3-dependent manner. The activation of AMPK reduced AKT activation, and led to dephosphorylation and nuclear translocation of FOXO3. Subsequent mutation studies indicated that bim gene activation during excitotoxic injury required direct FOXO3 phosphorylation by AMPK in the nucleus as a second activation step. Inhibition of this phosphorylation prevented Bim expression and protected neurons against excitotoxic and oxygen/glucose deprivation-induced injury. Systems analysis and computational modeling revealed that these two activation steps defined a coherent feedforward loop; a network motif capable of filtering any effects of short-term AMPK activation on bim gene induction. This may prevent unwanted AMPK-mediated Bim expression and apoptosis during transient or physiological bioenergetic stress

Metformin use and cardiovascular outcomes after acute myocardial infarction in patients with type 2 diabetes: a cohort study

Background: The use of metformin after acute myocardial infarction (AMI) has been associated with reduced mortality in people with type 2 diabetes mellitus (T2DM). However, it is not known if it is acutely cardioprotective in patients taking metformin at the time of AMI. We compared patient outcomes according to metformin status at the time of admission for fatal and non-fatal AMI in a large cohort of patients in England. Methods: This study used linked data from primary care, hospital admissions and death registry from 4.7 million inhabitants in England, as part of the CALIBER resource. The primary endpoint was a composite of acute myocardial infarction requiring hospitalisation, stroke and cardiovascular death. The secondary endpoints were heart failure (HF) hospitalisation and all-cause mortality. Results: 4,030 patients with T2DM and incident AMI recorded between January 1998 and October 2010 were included. At AMI admission, 63.9% of patients were receiving metformin and 36.1% another oral hypoglycaemic drug. Median follow-up was 343 (IQR: 1–1436) days. Adjusted analyses showed an increased hazard of the composite endpoint in metformin users compared to non-users (HR 1.09 [1.01–1.19]), but not of the secondary endpoints. The higher risk of the composite endpoint in metformin users was only observed in people taking metformin at AMI admission, whereas metformin use post-AMI was associated with a reduction in risk of all-cause mortality (0.76 [0.62–0.93], P = 0.009). Conclusions: Our study suggests that metformin use at the time of first AMI is associated with increased risk of cardiovascular disease and death in patients with T2DM, while its use post-AMI might be beneficial. Further investigation in well-designed randomised controlled trials is indicated, especially in view of emerging evidence of cardioprotection from sodium-glucose co-transporter-2 (SGLT2) inhibitors

Concerted Regulation of cGMP and cAMP Phosphodiesterases in Early Cardiac Hypertrophy Induced by Angiotensin II

Left ventricular hypertrophy leads to heart failure and represents a high risk leading to premature death. Cyclic nucleotides (cAMP and cGMP) play a major role in heart contractility and cyclic nucleotide phosphodiesterases (PDEs) are involved in different stages of advanced cardiac diseases. We have investigated their contributions in the very initial stages of left ventricular hypertrophy development. Wistar male rats were treated over two weeks by chronic infusion of angiotensin II using osmotic mini-pumps. Left cardiac ventricles were used as total homogenates for analysis. PDE1 to PDE5 specific activities and protein and mRNA expressions were explored