449 research outputs found
Orthorhombic 11C pyrrhotite from Michałkowa, Góry Sowie Block, The Sudetes, Poland - preliminary report
This study provides the preliminary report about first occurrence of orthorhombic 11C pyrrhotite (Fe (1-x) S) from the Sudetes, Poland. Samples of pyrrhotite-containing two-pyroxene gabbro were found in a classic pegmatite locality in Michałkowa near Walim in the Góry Sowie Block. Based on microscopic methods, pyrrhotite is associated with pentlandite, chalcopyrite, chromite, ilmenite, gersdorffite, magnetite, biotite, magnesio-hornblende, clinochlore, lizardite and talc. X-Ray diffraction (XRD) indicate that pyrrhotite has orthorhombic 11C structure and it is characterized by: a = 3.433(9) Å, b = 5.99(2) Å, c = 5.7432(5) Å, β = 90º and d 102 = 2.06906 Å. Mössbauer studies confirmed the XRD data. Pyrrhotite has three sextets with hyperfine parameter values 30.8 T for sextet A, 27.9 T and 25.8 T for sextets B and C respectively, indicating orthorhombic structure, the composition near Fe 10 S 11 and x = 0.0909
Demographics, practice patterns and long-term outcomes of patients with non–ST-segment elevation acute coronary syndrome in the past two decades: the CREDO-Kyoto Cohort-2 and Cohort-3
OBJECTIVES: To evaluate patient characteristics and long-term outcomes in patients with non-ST-segment elevation acute coronary syndrome (NSTEACS) in the past two decades. DESIGN: Multicenter retrospective study. SETTING: The Coronary REvascularization Demonstrating Outcome Study in Kyoto (CREDO-Kyoto) percutaneous coronary intervention (PCI)/coronary artery bypass grafting (CABG) Registry Cohort-2 (2005-2007) and Cohort-3 (2011-2013). PARTICIPANTS: 3254 patients with NSTEACS who underwent first coronary revascularisation. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was all-cause death. The secondary outcomes were cardiovascular death, cardiac death, sudden cardiac death, non-cardiovascular death, non-cardiac death, myocardial infarction, definite stent thrombosis, stroke, hospitalisation for heart failure, major bleeding, any coronary revascularisation and target vessel revascularisation. RESULTS: Patients in Cohort-3 were older and more often had heart failure at admission than those in Cohort-2. The prevalence of PCI, emergency procedure and guideline-directed medical therapy was higher in Cohort-3 than in Cohort-2. In patients who received PCI, the prevalence of transradial approach, drug-eluting stent use and intravascular ultrasound use was higher in Cohort-3 than in Cohort-2. There was no change in 3-year adjusted mortality risk from Cohort-2 to Cohort-3 (HR 1.00, 95% CI 0.83 to 1.22, p=0.97). Patients in Cohort-3 compared with those in Cohort-2 were associated with lower adjusted risks for stroke (HR 0.65, 95% CI 0.46 to 0.92, p=0.02) and any coronary revascularisation (HR 0.76, 95%CI 0.66 to 0.87, p<0.001), but with higher risk for major bleeding (HR 1.25, 95% CI 1.06 to 1.47, p=0.008). The unadjusted risk for definite stent thrombosis was lower in Cohort-3 than in Cohort 2 (HR 0.29, 95% CI 0.11 to 0.67, p=0.003). CONCLUSIONS: In the past two decades, we did not find improvement for mortality in patients with NSTEACS. We observed a reduction in the risks for definite stent thrombosis, stroke and any coronary revascularisation, but an increase in the risk for major bleeding
Ischemic and Bleeding Risk After Percutaneous Coronary Intervention in Patients With Prior Ischemic and Hemorrhagic Stroke
Background: Prior stroke is regarded as risk factor for bleeding after percutaneous coronary intervention (PCI). However, there is a paucity of data on detailed bleeding risk of patients with prior hemorrhagic and ischemic strokes after PCI. Methods and Results: In a pooled cohort of 19 475 patients from 3 Japanese PCI studies, we assessed the influence of prior hemorrhagic (n=285) or ischemic stroke (n=1773) relative to no-prior stroke (n=17 417) on ischemic and bleeding outcomes after PCI. Cumulative 3-year incidences of the co-primary bleeding end points of intracranial hemorrhage, non-intracranial global utilization of streptokinase and tissue plasminogen activator for occluded coronary arteries (GUSTO) moderate/severe bleeding, and the primary ischemic end point of ischemic stroke/myocardial infarction were higher in the prior hemorrhagic and ischemic stroke groups than in the no-prior stroke group (6.8%, 2.5%, and 1.3%, P<0.0001, 8.8%, 8.0%, and 6.0%, P=0.001, and 12.7%, 13.4%, and 7.5%, P<0.0001). After adjusting confounders, the excess risks of both prior hemorrhagic and ischemic strokes relative to no-prior stroke remained significant for intracranial hemorrhage (hazard ratio (HR) 4.44, 95% CI 2.64-7.01, P<0.0001, and HR 1.52, 95% CI 1.06-2.12, P=0.02), but not for non-intracranial bleeding (HR 1.18, 95% CI 0.76-1.73, P=0.44, and HR 0.94, 95% CI 0.78-1.13, P=0.53). The excess risks of both prior hemorrhagic and ischemic strokes relative to no-prior stroke remained significant for ischemic events mainly driven by the higher risk for ischemic stroke (HR 1.46, 95% CI 1.02-2.01, P=0.04, and HR 1.49, 95% CI 1.29-1.72, P<0.0001). Conclusions: Patients with prior hemorrhagic or ischemic stroke as compared with those with no-prior stroke had higher risk for intracranial hemorrhage and ischemic events, but not for non-intracranial bleeding after PCI
Synthesis of Cu-containing Diopside through a One-Step Crystallization
The incorporation of copper into pyroxene structure was investigated through the melt quenching technique and one-step crystallization procedure. Two series of glasses have been studied, one set with Ca=Mg and another set with Ca>Mg in diopside formula Cux(Ca Mg)2-xSi2O6. The glasses were nucleated by TiO2, Cr2O3, or CaF2 additions as nucleating agents to variably control the phases produced. X-ray diffraction (XRD), scanning electron microscopy, and energy-dispersive X-ray spectroscopy (EDX) were used to characterize the obtained samples. The heat treatment studied at 700, 800, 900 and 1000 °C for 2 h produced green and dark green glasses based on Cu-containing diopside. Various crystalline wollastonite, cuprite, tenorite, cristobalite, quartz, and fluorite phases were developed with different ratios combined with diopside formation depending on the heat treatment and nucleating agents used. As the heat treatment increased in temperature, the crystallized fraction increased with the development of nano-aggregates and the observed reticulated textures confirmed a radical change in the euhedral crystals. This emphasizes that the Cu-containing diopside can be created by a facile one step process. These compositions may find some applications in biological and optical fields
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Ball milling as an effective route for the preparation of doped bornite: synthesis, stability and thermoelectric properties
Bornite, Cu5FeS4, is a naturally-occuring mineral with an ultralow thermal conductivity and potential for thermoelectric power generation. We describe here a new, easy and scalable route to synthesise bornite, together with the thermoelectric behaviour of manganese-substituted derivatives, Cu5Fe1-xMnxS4 (0 ≤ x ≤ 0.10). The electrical and thermal transport properties of Cu5Fe1-xMnxS4 (0 ≤ x ≤ 0.10), which are p-type semiconductors, were measured from room temperature to 573 K. The stability of bornite was investigated by thermogravimetric analysis under inert and oxidising atmospheres. Repeated measurements of the electrical transport properties confirm that bornite is stable up to 580 K under an inert atmosphere, while heating to 890 K results in rapid degradation. Ball milling leads to a substantial improvement in the thermoelectric figure of merit of unsusbtituted bornite (ZT = 0.55 at 543 K), when compared to bornite prepared by conventional high-temperature synthesis (ZT < 0.3 at 543 K). Manganese-substituted samples have a ZT comparable to that of unsubstituted bornite
Ore Mineralogy
Subeconomic concentrations of copper sulfide minerals are irregularly distributed throughout the Lower Permian Wellington Formation and the Ninnescah Shale of south-central Kansas. The host rocks consist principally of gray shales and siltstones with lesser argillaceous dolomites and limestones in which the sulfides occur principally as replacements of earlier diagenetic pyrite or as irregular stringers.
Although two spatially distinct and separate sulfide assemblages are identified on the basis of drill hole information, the sequence of ore minerals indicates that a descending copper-rich solution percolating downward was slowly depleted of its copper content
In the northern portion of the area, pyrite is replaced by chalcopyrite and bornite at shallower depths, while in the southern part of the area pyrite is replaced by "chalcocite-like" minerals. It is suggested that pH and oxygen fugacity are controlling factors responsible for the different assemblages.
Electron microprobe studies indicate that no true chalcocite (Cu2S) is present; instead two phases having the compositions Cu1.78±0.04S (similar to anilite) and Cu1.91±0.03S (similar to djurleite) were identified. The mineral anilite has not been reported before associated with the Midcontinent copper occurrences.
We propose that the mafic rocks associated with the Central North American Rift System were the source rocks of the copper that was subsequently introduced into the Permian basin and adsorbed onto the sediments. Oxidizing ground waters were responsible for redissolving the copper and secondarily concentrating it in a reduced environment
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