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Leaching of a copper residue, produced by selective oxidative leaching of a nickel matte, in oxygenated sulfuric acid solution in the presence of chloride ions was investigated. The leaching behaviors of copper and nickel in the copper residue were determined. The effects of chloride addition, oxygen flowrate, sulfuric acid concentration, and temperature were studied as leaching variables. Addition of chloride in small amounts into the leach slurry was found to enhance copper leaching from the residue. (C) 2001 Elsevier Science B.V. All rights reserved.

Particle impact erosion is usually tested experimentally using one of two major types of erosion testing device; the gas-blast tester and the centrifugal accelerator type tester. The influence of the choice of the tester on the erosion results obtained has been recognised, together with the need for a better understanding of particle dynamics within the testers to allow correct interpretation of the erosion test results. To date, relatively little work has been carried out on understanding particle dynamics in the centrifugal tester, and this paper attempts to redress this. The paper considers the dynamics of particles travelling down the acceleration tube in the tester. A comprehensive physical model is described taking account of airflow in the acceleration tubes, particle rotation and friction effects. This led to the development of a computational model to predict the particle velocity vector (particle velocity and exit angle). The predictive model indicates the important influence of particle shape on particle dynamics and suggests that particle size has little effect. This implies a sensitivity of particle velocity and exit angle to the coefficient of friction of the particle in the acceleration tubes. Experimental measurements were carried out and the results verified the predictions of the model.

During recent erosion research at the University of Greenwich using a rotating disc accelerator erosion tester no peak has been observed in the curve of erosion damage vs. angle of impingement. This lack of peak has been observed for tests on a range of steels at a variety of particle impact velocities and fluxes and is contrary to previously reported results. Results of erosion tests on targets at various orientations are given in this paper. The targets used in this work were all made from 0.8% carbon steel (SAE1074). It is shown that changing the orientation of the target in such a tester can lead to different mechanisms of impact erosion occurring owing to changes in the particle dynamics at impact. Several reasons for this behaviour are suggested by the authors including: (a) the variation of particle flux across the target surface as the angle of orientation of the target to the flow of particles is changed, (b) the variation in the occurrence of inter-particulate collisions with the angle of target orientation, and (c) the effects of particle sliding on the walls of the acceleration mechanism inducing particle spin such that the mechanism of cutting is increased at low angles of particle impingement.

Clean processing of copper converter slags for reclaiming cobalt and copper could be a challenge. An innovative and environmentally benign approach for recovering metal values from such a slag was developed in the present work. Curing the slag with sulfuric acid, without re-smelting or roasting as currently practiced in the industry, made it amenable to leaching, and more than 95% of the cobalt and up to 90% of the copper was extracted, together with iron, by water leaching, leaving silica behind in a residue. Copper in the leach liquor was recovered by cementation with iron, and the dissolved iron crystallized as ferrous sulfate monohydrate. Cobalt in the pregnant solution rich in iron was recovered by either cementation or sulfide precipitation. Chemical and mineralogical characterization of the slag and its products were examined and compared to determine the nature of the changes occurring during curing and leaching. Operating variables were also investigated and optimized.

Would teachers' own lack of financial literacy inhibit their teaching financial education in the classroom? Using unique data from a sample of elementary school teachers in Taiwan, this paper examines the impact of teachers' personal financial literacy on the effectiveness of their financial education teaching. Our results substantiated that there is a positive correlation between teachers' financial literacy and financial education teaching. Furthermore, elementary school teachers underlying this study, as a group, show medium-high levels of financial literacy. Teachers generally believe that current elementary school textbooks cannot cultivate sufficient financial management knowledge in elementary school students, suggesting the unsuitability of financial education curricular materials for elementary school teachers. Finally, the results showed that elementary school teachers did not demonstrate significant differences in "highest degree earned," "college major," "number of years teaching social studies," or "school location" in terms of financial literacy as well as financial education teaching.

As pyrrhotite either dilutes nickel concentrates when recovered or causes significant metals loss and potential environmental harassments if discarded, production of separate pyrrhotite concentrate was thought as a reasonable alternative; however, processing it presents a challenge. A new process was studied to upgrade nickeliferous pyrrhotite concentrates using aqueous pressure oxidation under mild conditions, followed by sulfide precipitation and flotation. The effects of operation parameters such as oxygen pressure, temperature, initial acidity, retention time and concentrate composition were investigated. Pyrrhotite was found to be readily converted into iron oxide. The metal values present in the concentrate, principally nickel and copper, were dissolved in part as pyrrhotite was oxidized, then precipitated from the pulp as sulfides and finally recovered by flotation as a much higher grade concentrate with unreacted sulfide minerals and the produced elemental sulfur together. The pyrrhotite reporting to the leach residue as iron oxide was thus rejected in the flotation tailings.

To explore the effects of Notch signaling pathway and the vascular endothelial growth factor [VEGF(165)] gene on the functions of endothelial cells derived from rat bone marrow mesenchymal stem cells (MSCs).Isolated and cultivated rat bone marrow MSCs in vitro, then the cells were treated by VEGF165 and basic fibroblast growth factor (bFGF) for 2 weeks to induce them to differentiate into endothelial cells. The gene of VEGF165 was transfected into differentiated endothelial cells to promote the functions of the cells. The receptor Notch1 and the ligand Jagged1 of the Notch signaling were detected by reverse transcription-polymerase chain reaction (RT-PCR) before and after the transfection. γ-secretase inhibitor L-685458 was used to block Notch pathway. Migration ability of cells was detected by scarification test. Cells were inoculated on semisolid gel to study their ability of forming capillary-like structure.After transfection, VEGF165 mRNA could be detected on the differentiated endothelial cells. The expression of Jagged1 mRNA was up regulated(1.08 ± 0.01 vs. 1.01 ± 0.02,P0.01) and there was no change in Notch1 mRNA(0.60 ± 0.02 vs. 0.59 ± 0.01,P0.05). The ability of migration was enhanced (number of cells on the scratched area:46.45 ± 4.46 vs. 41.61 ± 1.42,P0.05), and the ability of forming capillary-like structure on semisolid gel showed no change (cells classification: 3.00 ± 0.89 vs. 2.00 ± 0.89,P0.05). After the transfection, using the γ-secretase inhibitor L-685458 to block the Notch signaling transduction, the ability of migration of the differentiated endothelial cells (number of cells on the scratched area: 51.72 ± 3.47 vs. 46.45 ± 4.46,P0.05), and that of forming capillary--like structure (cells classification: 4.17 ± 0.75 vs. 3.00 ± 0.89, P0.05), was also further enhanced.Transfection of the gene of VEGF165 into the differentiated endothelial cells can reinforce the function of these cells, and when Notch signaling was blocked, this effect can be further amplified.

To investigate the effect of salvianolic acid B (SAB) on the proliferation of human embryonic lung fibroblast MRC-5, and the secretion of procollagen I and endogenous transforming growth factor-beta1, (TGF-beta1).The MRC-5 cells were randomly divided into four groups as follows: the control group: cells cultured with DMEM but with no TGF-beta1, or SAB; the TGF-beta1, group: cell cultured with 10 ng/mL TGF-beta1; the SAB1 group: cell cultured with medium with 10 ng/mL TGF-beta1 and 1 pmol/L SAB; the SAB2 group: cell cultured with medium with 10 ng/mL TGF-beta1, and 10 pmol/L SAB. The proliferation of cells was assayed by MTT incorporation. The concentration of amino-terminal propeptide of type I procollagen (PINP), a marker of collagen synthesis, was measured by radioimmunoassay. The endogenous TGF-beta1, levels were measured using ELISA.The optical density, procollagen I contents, and endogenous TGF-beta1, levels significantly increased when compared with those of the control group (P0.05). Compared with the TGF-beta1, group, the optical density was obviously lowered, the procollagen I contents and endogenous TGF-beta1, levels significantly decreased in the SAB1 group and the SAB2 group, and better in the SAB2 group, showing statistical difference (P0.05).SAB could inhibit the proliferation of MRC-5 cells induced by TGF-beta1 and attenuate the roles of secreting collagen and endogenous TGF-beta1. It had the potential of postponing or delaying the progressive developing of pulmonary fibrosis.

To research the role of Notch signaling during the differentiation of bone marrow mesenchymal stem cells (MSCs) into endothelial cells and its effect on the functions of the differentiated cells.Rat bone marrow MSCs were isolated and cultured in vitro, then the cells were treated with vascular endothelial growth factor (VEGF165) and basic fibroblast growth factor (bFGF) for 2 weeks to induce it to differentiate into endothelial cells. The differentiated cells were identified by fluorescence immunoassay. The receptors and ligands of the Notch signaling were detected by reverse transcription-polymerase chain reaction (RT-PCR) before and after the differentiation. γ-secretase inhibitor was used to block Notch pathway. Migration ability of cells were assessed by scarification test. Cells were inoculated on semisolid gel to study their ability of forming the capillary-like structure.After inducing MSCs to differentiate into endothelial cells by VEGF165 and bFGF, MSCs gained the characteristics of the endothelial cells with expression of CD31 and Flk1. There were Notch1 mRNA and Jagged1 mRNA expressions in rat bone marrow MSCs. The expression changes in the receptor Notch1 were not statistically significant on the differentiated cells (0.59±0.01 vs. 0.59±0.01, P0.05), but there was a trend towards an increase of Jagged1 mRNA (1.01±0.02 vs. 0.99±0.03, P0.05). When Notch pathway was blocked, the differentiated cells' migration ability was increased (number of cells on the scratched area: 44.61±4.34 vs. 40.06±2.43, P0.05), and the ability of forming capillary-like structure was also increased (cells classification: 3.67±0.82 vs. 2.00±0.89, P0.01).Notch signaling may have an important role during the differentiation of MSCs into endothelial cells. The function of differentiated cells were strengthened when Notch pathway was blocked.

Aqueous pressure oxidation has been developed to a viable technology. It has found extensive commercial applications in mineral industry. Numerous pressure processing plants have been constructed worldwide for production of nickel, cobalt, copper and zinc from ores, concentrates and other metallurgical intermediates or secondary materials and for pretreatment of gold refractory ores. Successful operation of these plants provides hydrometallurgy with experience and confidence for its potential development and applications. This paper is intended to review the development and applications of pressure oxidation technology and the chemistry involved as well.

Solvent sublation (SS) has been investigated for separating gold from dilute chloride solutions using hexadecyltrimethylammonium bromide (HTMAB) both as collector and surfactant. The composition of organic and aqueous phases, and operating conditions such as gas flowrate and aeration time were studied. As a result, 10% 2-octanol in kerosene with 0.05 M Aliquat 336 was chosen as the organic phase. It is shown that gold can be separated quantitatively from a solution with only 10 ppm Au, with enrichment of 20. Comparisons to ion flotation (IF) and solvent extraction (SX) were also made. SS was found to be more effective than IF. SX is a little more effective than SS, but it takes as long as 24 h for phase disengagement, compared to

To evaluate the change in the plasma levels of serotonin (5-hydroxytryptamine) and neuropeptide (beta-endorphin, beta-EP) after injection of Yitongshu into Zusanli points in patients under mechanical ventilation.Twenty-eight patients undergoing mechanical ventilation were randomly divided into two groups: midazolam combined with fentanyl group (control group, n=14) and midazolam combined with fentanyl and Yitongshu group (Yitongshu group, n=14). The drugs were given to the patients continuously intravenously with an injection pump in an even rate, with the dosage adjusted to reach the sedative target of visual analog score (VAS)or =3-4 and Ramsay 2-4. Yitongshu injection (4 ml) was injected into the Zusanli point on both sides 11 hours or 23 hours after administration of the durgs in Yitongshu group. The hemodynamic and respiratory parameters, including mean arterial pressure (MAP), heart rate (HR), respiratory rate (RR), pulse oxygen saturation (SpO(2)), oxygenation index (PaO(2)/FiO(2)) and pressure airway (Paw), were recorded, and the sedation levels (VAS and Ramsay) were evaluated before sedation and 1, 12, 24 hours after sedation in these patients. The plasma levels of 5-hydroxytryptamine and beta-EP were examined before sedation, 12 hours and 24 hours after sedation.Compared with that before sedation, HR and VAS score were significantly lower, and Ramsay score was significantly higher in both groups. MAP was significantly lower at 1 hour, and RR at 12 hours and 24 hours , as well as the Paw at 24 hours, and the PaO(2)/FiO(2) was significantly higher at 24 hours. The level of 5-hydroxytryptamine at 12 hours and 24 hours in Yitongshu group [(101.45+/-14.67) ng/L, (104.86+/-11.74) ng/L] was significantly higher than that in control group [(61.57+/-10.62) ng/L, (59.86+/-8.64) ng/L, both P0.05]. But the level of beta-EP showed no difference between two groups [control group: (162.72+/-38.44) ng/L at 12 hours, (151.83+/-24.54) ng/L at 24 hours; Yitongshu group: (169.35+/-28.10) ng/L at 12 hours, (159.41+/-15.89) ng/L at 24 hours, both P0.05].Yitongshu injection can reduce the plasma level of 5-hydroxytryptamine in ventilated patients, but with no effect on beta-EP.

A greal deal of effort has been directed towards the development of economically and technically feasible processes for the chemical oxidation of iron sulfides. Such processes applied commercially or under active development, including roasting, and sulfate-, nitrate-, chloride- and alkaline-based aqueous oxidation processes, are outlined in this paper.

Oxidized copper ores are exhibiting increasingly their importance as copper resources as worldwide high grade copper sulfide deposits become depleted. Extensive chemical and technological efforts have been made to meet the demand of exploitation of such copper resources. This paper reviews the processes and modifications developed in the last three decades as the results of these efforts in flotation, hydrometallurgy and combined mineral processing and metallurgy processes. The emphasis is put on the refractory oxidized ores, with a special reference to a copper deposit at Tangdan of Dongchuan mine in Yunnan province of China.

The subepithelial fibrosis component of airway remodeling in asthma is mediated through induction of transforming growth factor-beta1 (TGF-beta1) expression with consequent activation of myofibroblasts to produce extracellular matrix proteins. The number of myofibroblasts is increased in the asthmatic airway and is significantly correlated with the thickness of lamina reticularis. However, much is still unknown regarding the origin of bronchial myofibroblasts. Emerging evidence suggests that myofibroblasts can derive from epithelial cells by an epithelial-to-mesenchymal transition (EMT). In this study we investigated whether TGF-beta1 could induce bronchial epithelial EMT in the human bronchial epithelial cell. Cultured human bronchial epithelial cells, 16HBE-14o, were stimulated with 10 ng/ml TGF-beta1. Morphologic changes were observed and stress fiber by actin reorganization was detected by indirect immunostaining. The expression of alpha-SMA (alpha-smooth muscle actin) and the epithelial cell marker E-cadherin were detected in those 16HBE-14o cells after TGF-beta1 stimulation for 72 h, using immunostaining and RT-PCR. The contents of collagen I were determined by radioimmunoassay, and the levels of endogenous TGF-beta1 were measured with ELISA. Human bronchial epithelial cells stimulated with TGF-beta1 were converted from a "cobblestone" epithelial structure into an elongated fibroblast-like shape. Incubation of human bronchial epithelial cells with TGF-beta1 induced de novo expression of alpha-SMA, increased formation of stress fiber by F-actin reorganization, and loss of epithelial marker E-cadherin. Moreover, a significant increase in the levels of collagen I and endogenous TGF-beta1 released from bronchial epithelial cells stimulated with TGF-beta1 were observed. These results suggested that human bronchial epithelial cells, under stimulation of TGF-beta1, underwent transdifferentiation into myofibroblasts.

Gallium bearing ferrites with different gallium content were synthesized by oxidation of ferrous and gallium ions under alkaline condition and room temperature. The samples were subjected to IR, XRD, Mossbauer spectral analysis and magnetization characterization. The results indicated that the green-rust intermediate phase would be produced during the procedure of Ga-Fe3O4 formation, and the green-rust intermediate phase was converted to ferrites with spinel structure during the drying under hot-N2 atmosphere. With the introduction of gallium into the spinel structure, the interplanar crystal spacing of the spinel structure decreased, as indicated from XRD spectra, and the lattice vibration of M(T)-O-M(o) moved to the high-frequency resulting from IR spectra. A small amount gallium introduction entered the tetrahedral sites preferentially rather than the octahedral sites, and increasing gallium introduction would enhance the occupation of octahedral sites. Furthermore, a small content of gallium in the initial solution could prevent the formation of non-magnetic Fe2O3.

A novel process was developed to apply phase transfer catalysis (PTC) to the sulfidization of the refractory oxidized copper ore which is not amenable to the conventional process of treating oxidized copper ore. Sulfur powder was used to sulfide forming agent in the presence of quaternary ammonium compounds as PT catalyst and kerosene as solvent for sulfur. A sample of refractory oxidized copper ore was treated by this process at 80°C for 2.5 h and recovered by flotation into a concentrate with grade of 12.6% Cu and with 81.5% recovery, which otherwise required the temperature of 180°C and reaction time of 4 h to achieve similar results.

Colloidal emulsion aphrons (CEAs) are considered as the micron-sized water-in-oil (W/O) emulsion-cores encapsulated by a "soapy shell" consisting of multi-layer surfactant molecules. In this dispersion, the emulsion-core sizes are mainly in 10-100 microm and that of the inner phase droplets are in 1-5 microm. CEAs not only behave analogously to emulsion liquid membrane (ELM) in extraction with advantages of high concentration ratio, counter-concentration extraction and combination of extraction with backwash together, but also have the large interface areas, easy scatteration and quick extraction which colloidal liquid aphrons (CLAs) possess. CEA extraction overcomes the restriction of partition equilibrium between the water and the oil phase that CLAs have. They have greater extraction capacity than CLAs. In this study, the application of CEAs to drug overdose treatment was studied using salicylic acid as the model drug, paraffin oil as the membrane phase, PEG-30 dipolyhydroxystearate (P135) as the hydrophobic surfactant, nonylphenol ethoxylate-10 (NP10) as the hydrophilic surfactant and NaOH solution as the receptor phase. Also some factors affecting the stability of this dispersion and extraction ratio were investigated. In order to prepare CEAs successfully, the concentrations of NP10 and P135 should be in 1.5-3.0% (w/v) and 0.25-1.0% (w/v), respectively, together with the ratio of the volume of oil phase to the volume of inner aqueous phase of CEAs, R(oi)> or =1:1. For the extraction of salicylic acid, the pH value of the feed phase was supposed to be lower than 2.0 and the suitable NaOH concentration of the receptor phase was higher than 0.02 mol/L. Under this condition, more than 98.7% of salicylic acid was transported into receptor phase in half a minute.

Chemical and mineralogical characterizations of a copper converter slag, and its products obtained by curing with strong sulphuric acid and leaching with hot water, were carried out using ore microscopy, scanning electronic microscopy with energy dispersive spectrometry, wave-length dispersive X-ray fluorescence spectrometry, X-ray diffractometry and chemical phase analysis, which provided necessary information to develop a new process for treating such slag and further understanding of the chemical and mineralogical changes in the process.

To study methods of diagnosis and treatment for atypical pneumonia (Severe Acute Respiratory Syndrome), outbreak of the illness in Guangzhou during Jan. - Mar., 2003.190 cases with atypical pneumonia were analyzed, and the cases were admitted in Guangzhou municipal First Hospital and Guangzhou municipal Eighth Hospital.Patients were infected by close quarters contacting each other. All patients manifest high fever, and accompany by dyspnea, cough, palpitate, weakness, headache and swirl. Other 46 cases were accompanied by diarrhea. Most of patients, manifestation of lungs was negative. Chest X-ray, shadow of lungs were light in beginning, and change to severity slowly or suddenly during 5 - 10 days. Of these cases, 36 cases develop to ARDS and 11 cases died with severity ARDS. Using general antibiotic was of no effect for the illness. Continual positive airway pressure (CPAP) and glucocorticoid was required that can control deprivation of the disease when toxicosis symptom of patients was severity and shadow of lungs diffuse more and more.Infectivity of the illness is evidence and spread by airway. Using general antibiotic was of no effect for the illness. Continual positive airway pressure (CPAP) and glucocorticoid are effective for control of the disease.