706 research outputs found
Understanding the role of ion interactions in soluble salt flotation
ManuscriptThere is anecdotal evidence for the significant effects of salt ions on the flotation separation of minerals using process water of high salt content. Examples include flotation of soluble salt minerals such as potash, trona and borax in brine solutions. Although some of the effects are expected, some do not seem to be encompassed by classical theories of colloid science. Several experimental and modeling techniques for determining solution viscosity, surface tension, bubble-particle attachment time, contact angle, atomic force microscopy, sumfrequency vibrational spectroscopy and molecular dynamics simulation have been used to provide further information on air-solution and solid-solution interfacial phenomena, especially the interfacial water structure due to the presence of dissolved ions. These studies indicate that the ion specific effect is the most significant factor influencing flotation in brine solutions
Efficient algorithm to extract components of a composite signal
An efficient algorithm is proposed to extract components of a composite signal. The proposed approach has two stages of processing in which the time-frequency supports of the individual signal components are identified and then the individual components are estimated by performing a simple time-frequency domain incision on the identified support of the component. The use of a recently proposed time-frequency representation [1] significantly improves the performance of the proposed approach by providing very accurate description on the auto-Wigner terms of the composite signal. Then, simple fractional Fourier domain incision provides reliable estimates for each of the signal components in O(N log N) complexity for a composite signal of duration N
Ottoman Masonry Bridges in Anatolia and the Balkans
Remains of the historical masonry bridges in Anatolia and the Balkans are dated back to the Roman (first half of the I. Millenium AD), to the Seldjukide (early centuries of the II. Millenium AD; basically in Anatolia), and to the Ottoman periods (13th to 19th centuries). Besides serving to transportation, bridges crossing watercourses have to be considered as important hydraulic structures. Built for military as well as economic purposes, more than one hundred Ottoman bridges (roughly two thirds in Anatolia and one third in the Balkans) served for several centuries; some of them being still in operation. They are silent witnesses of the hydraulic knowledge and solid construction technology of their times. In this inventory study, only Ottoman's masonry bridges in Anatolia and Balkans have been presented. Some of the Ottoman's masonry bridges had sunken in the reservoir of modern dams, some of them demolished during the construction of the new highways, and some of them are still in service
Theoretical investigation on exact blind channel and input sequence estimation
Recent work on fractionally spaced blind equalizers have shown that it is possible to exactly identify the channel and its input sequence from the noise-free channel outputs. However, the obtained results are based on a set of over-restrictive constrainst on the channel. In this paper it is shown that the exact identification can be achieved in a broader class of channels
High resolution time frequency representation with significantly reduced cross-terms
A novel algorithm is proposed for efficiently smoothing the slices of the Wigner distribution by exploiting the recently developed relation between the Radon transform of the ambiguity function and the fractional Fourier transformation. The main advantage of the new algorithm is its ability to suppress cross-term interference on chirp-like auto-components without any detrimental effect to the auto-components. For a signal with N samples, the computational complexity of the algorithm is O(N log N) flops for each smoothed slice of the Wigner distribution
Efficient computation of the Ambiguity Function and the Wigner Distribution on arbitrary line segments
Efficient algorithms are proposed for the computation of Wigner distribution and ambiguity function samples on arbitrary line segments based on the relationship of Wigner distribution and ambiguity function with the fractional Fourier transformation. The proposed algorithms make use of an efficient computation algorithm of fractional Fourier transformation to compute N uniformly spaced samples O(N log N) flops. The ability of obtaining samples on arbitrary line segments provides significant freedom in the shape of the grids used in the Wigner distribution or in ambiguity function computations
Pentoxifylline May Restore Kanamycin-Induced Renal Damage in Rats
Background: Kidney damage can be caused by many factors, such as using certain drugs in high doses or over the longterm. The use of one such group of drugs, aminoglycosides, which act as Gram-negative antibacterial therapeutic agents,can lead to nephrotoxicity. It has been hypothesized that aminoglycoside-induced nephrotoxicity might be prevented byusing pentoxifylline, which has antioxidant and anti-inflammatory effects and improves microcirculation. The objectiveof this present research was to determine the protective effects of pentoxifylline on kanamycin-induced kidney damage.Materials, Methods & Results: Thirty-two male Wistar rats were divided into four groups as follows: control, pentoxifylline,kanamycin, and kanamycin + pentoxifylline. The control group received intraperitoneal (IP) injections of 0.5 mL normalsaline solution once a day (d) (SID) for 20 d; the pentoxifylline group received IP injections of 50 mg/kg pentoxifyllinetwice a day (BID) for 20 d, the kanamycin group received subcutaneous (SC) injections of 500 mg/kg kanamycin SID for20 d, and the kanamycin + pentoxifylline group received both SC injections of 500 mg/kg kanamycin SID and IP injectionsof 50 mg/kg pentoxifylline BID for 20 d. At the end of 20 d, blood samples were taken from the heart by cardiac punctureunder general anesthesia. After euthanizing the rats by cervical dislocation under anesthesia, the kidneys were immediatelyremoved, relative kidney weights were calculated, and routine pathologic evaluations were conducted. Hemogramparameters were measured using a blood cell count apparatus and serum biochemical parameters were measured usingan autoanalyzer. Kanamycin also caused (P < 0.05) tubular degeneration and tubular dilatation. Although pentoxifyllinesignificantly reduced the level of kanamycin-induced tubular degeneration (P < 0.05), it did not significantly reduce tubulardilatation. Increases in relative kidney weights (P < 0.05) and in interstitial mononuclear cell (MNC) infiltrates wereobserved in the kanamycin and kanamycin + pentoxifylline groups compared to those in the control and pentoxifyllinegroups. Statistically significant changes were determined in the levels of some hemogram and biochemical parameterswithin reference ranges (P < 0.05).Discussion: In this study, both tubular degeneration and dilatation were observed in the kanamycin group. Pentoxifyllineinhibited (P < 0.05) kanamycin-induced tubular degeneration and appeared to also reduce tubular dilatation, although thisreduction was not significant. Tubular necrosis, epithelial edema of proximal tubules, tubular fibrosis, and perivascularinflammation might also be observed in aminoglycoside-induced nephrotoxicity. In current research, pentoxifylline preventedtubular damage induced by kanamycin, but did not inhibit infiltration by MNCs. Pentoxifylline also amelioratedamikacin- or gentamycin-induced histopathologic changes, especially those associated with tubular structures. The protectiveeffects of pentoxifylline on kanamycin-induced tubular nephrotoxicity in this research might be a result of its stimulatingthe production of prostaglandin, a vasodilator, and of its improving microcirculation. Although the anti-inflammatoryeffects of pentoxifylline have been reported, these did not inhibit kanamycin-induced infiltration by interstitial MNCs inthe present study. These results could indicate that the anti-inflammatory effects of pentoxifylline are not obvious and/orare dose dependent. Statistically significantly changes were determined in the levels of some hemogram and biochemicalparameters in reference ranges. However, these changes were within the reference ranges for rats. These results suggestedthat kanamycin-induced tubular degeneration and dilatation might be prevented by administering pentoxifylline
Can the mean platelet volume be a predictor of disease activity in primary Sjogren syndrome?
Background: Disease activity in primary Sjogren syndrome (PSS) is measured by the EULAR Sjogren’s syndrome disease activity index (ESSDAI) and patient reported index (ESSPRI). Studies investigating the association between ESSDAI and ESSPRI and previously reported indicators of systemic inflammation are few in the literature. The aim of this study was to determine the clinical utility of the mean platelet volume (MPV) in predicting disease activity in PSS patients.Methods: A total of 190 subjects including ninety-five PSS patients and ninety-five healthy controls were enrolled. Associations between MPV and other known indicators of systemic inflammation (red cell distribution width (RDW), neutrophil to lymphocyte ratio (NLR) and patient clinical characteristic, ESSDAI and ESSPRI were investigated by using spearman correlation and linear regression analysis.Results: MPV levels were found to be significantly higher in the PSS group than the control group (10.5±1.2 versus 9.0±1; P<0.001 respectively). Correlation and regression analysis showed a positive correlation between MPV levels and ESSDAI scores (r=0.24, p=0.01). There was a negative correlation between ESSPRI and MPV levels (r=-0.32, p=0.001). NLR and RDW did not show any significant correlation with either ESSDAI or ESSPRI scores.Conclusions: MPV levels are significantly elevated in PSS patients compared to their control peers, positively correlate with ESSDAI but negatively with ESSPRI scores. MPV might be a useful inflammatory marker to measure disease activity in PSS.
Anti-phospholipase A2 Receptor Antibody Measurement in Patients with Idiopathic Membranous Nephropathy Diagnosed by Renal Biopsy
Objective: Our study is a cross-sectional study that aims to evaluate the presence and levels of anti-phospholipase A2 receptor (PLA2R) antibodies in healthy volunteers and idiopathic membranous nephropathy (IMN) patients and to assess the relationship between these levels and clinical parameters.
Methods: Serum anti-PLA2R antibody levels, complete blood count, urea, creatinine (Kre), total protein,albumin, low-density lipoprotein (LDL)-cholesterol, triglycerides (TG), high-density lipoprotein (HDL)-cholesterol, total cholesterol, C-reactive protein (crp), sedimentation, proteinuria were measured from 71 IMN patients and 48 healthy volunteers.
Results: Of the values compared between the two groups, the urea, creatinine, and modified diet renal disease (MDRD) were similar, total protein, albumin, LDL-cholesterol, TG, total cholesterol, HDL-cholesterol, and complete urinalysis protein values were statistically significantly high in the patient group, as expected in nephrotic syndrome (p\u3c0.01). The anti-PLA2Rantibody levels measured using enzyme-linked immunosorbent assay (ELISA) in patient and control groups were found to be negative. The anti-PLA2R level was found to be 0.104 (0.093-0.129) ng/ml in the IMN group, while it was 0.141 (0.117-0.177) ng/ml in the control group (P=0,001). Although the P value was significant, the anti-PLA2R antibody level was found to be high in the control group and was outside the reference range of the kit.
Conclusion: There is a need to conduct more sensitive studies with a higher number of patients in order to distinguish between primary and secondary nature and to investigate the presence of anti-PLA2R in IMNpatients, which constitute the majority of nephrotic syndromes in adults. Antibody titer levels were observed to be low and it was revealed that the measurement range of the antibody kit used in the study should be more sensitive
Characterization of Flocs in Dewatering of Coal Plant Tailings
Flocculation is a widely used method for dewatering fine coal tailings. Flocs must resist to the shear stresses during the following processes such as flotation, cyclone separation, and pumping. Therefore, the strength of the flocs must be considered during flocculation. In this study, the fine coal tailings were dewatered with an anionic flocculant SNF-923 at various dosages, and the floc size of the coal tailings was characterized using a laser diffraction particle size analyzer with respect to time in order to determine the change in the floc size and hence the floc strength. The results of this study clearly indicated that the determination of the floc size with a laser particle size analyzer could be a simple and good method to observe the flocculation efficiency in terms of the floc strength
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