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In this study, the relationships between the liberation degree and the kinetic breakage parameters of a chromite ore obtained from the Burdur (Türkiye) were examined under the laboratory conditions. Firstly, liberation degrees for chromite particles were determined by the particle counting method in a metal microscope for 4 different size groups. Secondly, the breakage parameter of chromite ore which was dry ground with a ball mill was obtained using standard test methods. Additionally, the model parameters were also determined for the fractional interstitial fillings (U) of the chromite sample. Thirdly, the kinetic grinding parameters were compared with the liberation degree of the chromite sample. As a result of the tests, a very good correlation was obtained with R2=0.998, and regression analysis in the grinding processing of the chromite ore was used to verify the validity of the relationship parameter of Si that was produced. To these, it was found that interstitial fillings (U=0.6, 0.8, 1.0, and 1.2) have an effect on the grinding. [ABSTRACT FROM AUTHOR]

The air-to-pulp ratio and bias factor are important operating parameters in the Jameson flotation cell. These parameters have significant effect on micro-events taking place between particles and bubbles in flotation, and hence on flotation performance. In this study, the possibilities of obtaining a Cu-Zn rich bulk concentrate from complex sulphide ore from the Cayeli region (Turkey) were investigated using the lab-scale Jameson cell. The effect of air-to-pulp ratio and bias factor on flotation recovery were also studied. The ore has problematic flotation behaviour due to very fine liberation size and oxidation. The results showed that the Cu-Zn rich bulk concentrate can be obtained from the ore with satisfactory grade and recovery. It was determined that the air-to-pulp ratio and bias factor have significant effect on the flotation recovery. The optimum values of air-to-pulp ratio and bias factor in flotation of rather fine sized minerals were determined to be within the range of 1-1.5 and 0.70-0.95, respectively. [ABSTRACT FROM AUTHOR]

Background: Saphenous vein graft disease (SVGD) after by-pass surgery is an important cause of morbidity and mortality for patients with coronary artery disease. Comprehensive evaluation of biochemical and hematological parameters associated with this problem is limited. Plateletcrit (PCT) provides complete information on total platelet mass, but it has not been previously studied. In this study, we examined the relationship between SVGD and platelet parameters such as PCT, mean platelet volume, platelet count, and platelet distribution., Methods: We retrospectively analyzed 14,398 patients who underwent coronary angiography between February 2006 and August 2012. Records from 893 patients with previous coronary artery by-pass graft operation were re-evaluated. A total of 251 cases were divided into two groups (127 patients receiving a saphenous vein graft; 124 patients diagnosed with SVGD) and hematological and biochemical parameters were compared., Results: There were no significant differences in clinical characteristics between the two groups except that the SVGD group had a higher median time from surgery to coronary angiography than the patent saphenous vein graft group [7 years (2-16) vs. 5 years (2-15), p < 0.001]. The SVGD groups also had significantly higher median PCT, mean platelet volume, platelet count, uric acid level, and red blood cell distribution width. The cut-off value for PCT was found to be 0.188 for predicting SVGD, with an 80.65 % sensitivity and 81.1 % specificity., Conclusion: Plateletcrit has an important predictive value for SVGD, and it could be used as a marker for anti-platelet therapy to prevent graft atherosclerosis in patients undergoing by-pass surgery.

Background: Metabolic syndrome (MetS) is a strong predictor of cardiovascular events. Coronary flow reserve (CFR), as determined by transthoracic echocardiography, is an indicator of microvascular function. In this study, we sought to determine whether CFR is impaired in patients with MetS without clinical coronary heart disease., Methods: Thirty-three patients with MetS (mean age, 67+/-8 years) and 35 age- and sex-matched controls were studied prospectively. Transthoracic two-dimensional and Doppler echocardiography was performed on all patients. Baseline and hyperemic (after dipyridamole infusion) coronary flow rates were measured using pulsed Doppler echocardiography. CFR was calculated as the ratio of hyperemic to baseline diastolic peak velocities., Results: There was no difference with regard to baseline systolic and diastolic coronary flow rates in patients with MetS compared with control subjects (19.9+/-3.1cm/s vs. 19.7+/-2.9cm/s, P>.05; and 27.7+/-4.2cm/s vs. 27.1+/-3.6cm/s, P>.05, respectively). Hyperemic diastolic flow and CFR were significantly lower in patients with MetS than in controls (61.7+/-9.4cm/s vs. 70.2+/-9.2cm/s, P<.0001; and 2.2+/-0.5 vs. 2.6+/-0.4, P=.001, respectively). In a logistic regression analysis that included age, sex, body mass index, hypertension, and dyslipidemia and MetS, MetS was the only predictor of a CFR<2.5 (P=.007, OR=6.1, 95% CI: 1.6-23.3)., Conclusion: In conclusion, CFR is impaired in patients with MetS suggesting that coronary microvascular dysfunction, an early finding of atherosclerosis, is present in this patient population. Metabolic syndrome is associated with a CFR<2.5.

Background: It has been shown that the patients with inflammatory rheumatic diseases such as systemic lupus erythematosus and rheumatoid arthritis have an increased risk of developing atherosclerosis. However, the association of ankylosing spondylitis (AS) to atherosclerosis and related diseases is still controversial. Accordingly, we investigated coronary flow reserve (CFR) and left ventricular (LV) diastolic function in patients with AS using transthoracic Doppler echocardiography., Methods: CFR and LV diastolic function were studied in 40 patients with AS (38.9+/-10.2 years, 26 males) and 35 healthy volunteers (37.5+/-6.4 years, 23 males). Coronary diastolic peak flow velocities (DPFV) were measured at baseline and after dipyridamole infusion. CFR was calculated as the ratio of hyperemic to baseline DPFV. LV diastolic function was assessed by both standard and tissue Doppler imaging., Results: Demographic features and coronary risk factors except diastolic blood pressure were similar between the groups. CFR were significantly lower in the AS group than in the control group (2.20+/-0.46 versus 3.02+/-1.50, P<0.0001). Reflecting LV diastolic function mitral A-wave and E/A ratio were borderline significant, and mitral E-wave deceleration time and isovolumic relaxation time were significantly different between the groups. Serum hsCRP and TNF-alpha levels were significantly higher in the patients with AS, and hsCRP and TNF-alpha levels independently correlated with CFR., Conclusion: These findings show that CFR reflecting coronary microvascular function and LV diastolic function are impaired in patients with AS, and severity of these impairments correlate well with hsCRP and TNF-alpha. These results suggest that impaired CFR may be an early manifestation of cardiac involvement in patients with AS.

We studied unique cerebral blood flow (CBF) responses to cortical spreading depression in mice using a novel two-dimensional CBF imaging technique, laser speckle flowmetry. Cortical spreading depression caused a triphasic CBF response in both rat and mouse cortex. In rats, mild initial hypoperfusion (approximately 75% of baseline) was followed by a transient hyperemia reaching approximately 220% of baseline. In mice, the initial hypoperfusion was pronounced (40-50% of baseline), and the anticipated hyperemic phase barely reached baseline. The duration of hypoperfusion significantly correlated with the duration of the DC shift. As a possible explanation for the pronounced hypoperfusion, mouse cerebral vessels showed enhanced resistance to relaxation by acetylcholine (3 microM) after K+ -induced preconstriction (20, 40, and 80 mM) but dilated normally in response to acetylcholine after preconstriction with U46619, a synthetic thromboxane A2 analog. By contrast, rat vessels dilated readily to acetylcholine after preconstriction by K+. The transient normalization of CBF after hypoperfusion in the mouse was abolished by L-NA but not 7-NI. In summary, the CBF response to cortical spreading depression in mice contrasts with the rat in that the initial hypoperfusion is pronounced, and the hyperemic phase is markedly diminished. The differences in CBF response between species may be in part caused by an increased sensitivity of mouse cerebral vessels to elevated extracellular K+.