Ultrafiltration Research Papers - Academia.edu (original) (raw)

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- Robotics, Materials Science, Technology, Medicine
- by Toraj Mohammadi
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- Engineering, Modeling, Ultrafiltration, Desalination
- by Rahim Jassim
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- Engineering, Turbulence, Filtration, Activated Sludge
- by Eran Lavy
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- Kinetics, Quality Control, Ultrafiltration, Computer Simulation
- by Adalberto Noyola
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- Chemistry, Medicine, Multidisciplinary, Ultrafiltration

This study investigated the removal efficiency and mechanisms of water contaminants (mainly N-nitrosamines) during municipal wastewater reclamation by a membrane bioreactor (MBR) and nanofiltration (NF) hybrid system. The removal of bulk water contaminants was governed by the microbial activities in the MBR and molecular weight cut-off (MWCO) of the NF membranes. The removal of N-nitrosamines by the MBR was primarily attributed to biodegradation by aerobic bacteria, which can be determined by the reactivity of the amine functional groups with the catabolic enzymes (removal efficiency=45-84%). Adsorption and formation of membrane fouling can enhance the removal of N-nitrosamines by the NF membranes. However, size-exclusion is found to play a major role in the removal of N-nitrosamines by the NF membranes since the removal efficiencies of N-nitrosamines varied significantly depending on molecular weight of the N-nitrosamines and MWCO of the NF membranes (removal efficiency: NE90>NE...

- by Kangmin Chon
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- Water Purification, Nanoparticles, Multidisciplinary, Ultrafiltration

Background Remaining edema-free is a challenge for many automated peritoneal dialysis (APD) patients, especially those with fast (“high”) transport characteristics. Although increased use of peritoneal dialysis (PD) solutions with high glucose concentrations may improve volume control, frequent use of such solutions is undesirable. Methods We used the 3-pore kinetic model to evaluate 4 alternative therapy prescriptions for the APD day exchange in anuric patients with high, high-average, and low-average transport characteristics. Four prescriptions were modeled: Therapy 1: Optimal, individualized dwell times with a dry period Therapy 2: Use of a midday exchange Therapy 3: Use of an icodextrin-containing dialysate during a 14-hour dwell Therapy 4: Use of optimal, individualized dwell times, followed by an icodextrin dwell to complete the daytime period The alternative therapies were compared with a reference standard therapy using glucose solution during a 14-hour dwell. The nighttime...

- by James Sloand
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- Medicine, Ultrafiltration, Humans, Computer Simulation

This paper presents the possibility of removing metal ions by applying the hybrid complexationultrafiltration process. The research was conducted on model solutions containing Zn(II) and Ni(II) ions. The complexing agent applied in the... more

- by Irena Korus
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- Chemical Engineering, Analytical Chemistry, Ultrafiltration, Metal Complexes
- by Birgitte Ahring
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- Multidisciplinary, Ultrafiltration, Transducers, Temperature
- by Francis Digiano
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- Water, High Pressure, Carbon, Water Purification
- by Juan Bosch
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- Pediatrics, Acute kidney injury, Medicine, Ultrafiltration
- by Kirti V . Dubey
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- Engineering, Technology, Ultrafiltration, Adsorption
- by Melis Cagdas
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- Pharmaceutical Chemistry, Ultrafiltration, Cholesterol, Pharmaceutical

Hypervolemia is a risk factor for left ventricular hypertrophy and hypertension in peritoneal dialysis patients. Icodextrin improves volume control by increasing ultrafiltration in peritoneal dialysis patients. To examine the effects of twice-daily icodextrin administration on blood pressure and left ventricular hypertrophy in peritoneal dialysis patients with hypervolemia and ultrafiltration failure. Administration of icodextrin twice daily resulted in a significant reduction in the left ventricular mass index (LVMI) of patients by the end of the third month (p < 0.05). The reduction in LVMI was also significant for the once-daily icodextrin group (p < 0.05). Mean blood pressure of patients receiving icodextrin twice daily was significantly reduced (p < 0.05). By the end of the third month no significant changes were observed in mean blood pressure of the patients using once-daily icodextrin (p > 0.05). No statistically significant changes were observed in weekly total ...

- by Bulent Tokgoz
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- Treatment Outcome, Ultrafiltration, Echocardiography, Humans
- by Mohammad al-Masri
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- Engineering, Water Purification, Syria, Ultrafiltration

Monomer detergent concentrations of Triton X-100, Chaps (3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate), and sodium dodecyl sulfate in guanidine hydrochloride, formamide, and urea solutions were measured by an ultrafiltration procedure. This simple and rapid procedure effectively separated the monomer forms of these detergents from their respective micelle forms. Critical micellar concentrations of these detergents in water measured by this procedure agreed well with previously reported values. Both ionic and nonionic chaotropic agents, e.g., guanidine hydrochloride, formamide, and urea, are demonstrated to significantly shift the equilibrium between the monomer and the micellar form of various detergents toward the direction of monomer in a concentration-dependent manner. Thus, monomer/micelle ratio of detergents in solution can be manipulated over a wide range by the concomitant use of chaotropic solvents. This has direct applications in experiments involving destruction of biomembranes and solubilization of hydrophobic molecules in aqueous solutions.

- by Ronald Midura
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- Analytical Chemistry, Ultrafiltration, Micelles, Urea
- by Dalene Beer
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- Engineering, Ultrafiltration, Wine, Antioxidants
- by Jerry Wu
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- Kinetics, Water Purification, Multidisciplinary, Ultrafiltration
- by Hou-min Chang
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- Engineering, Technology, Biotechnology, Ultrafiltration

3-Deoxyglucosone (3DG), a reactive dicarbonyl, is an important intermediate in the formation of advanced glycation end products (AGEs). The AGEs are particularly important in diabetes since they have been correlated with the development of diabetic complications. Consequently, measurements of 3DG are likely to provide valuable insights into the role of this metabolite in the etiology of diabetic complications. While several methods of 3DG quantitation in human plasma have been previously published, a significant discrepancy (over 30-fold) exists in the reported values. Knecht et al. (Arch. Biochem. Biophys. 294, 130-137, 1992) have reported the levels of plasma 3DG in normoglycemics to be 61 nM, using a GC/MS procedure. In contrast to this, Niwa et al. (Biochem. Biophys. Res. Commun. 196, 837-843, 1993) reported 3DG levels to be 1800 nM in normoglycemics, using a totally independent GC/MS method. To resolve this disagreement and fill the need for a robust assay for this dicarbonyl, suitable for absolute quantitation, a GC/MS procedure was devised for its measurement. Plasma samples were deproteinized either by ultrafiltration or by addition of ethanol as described by Niwa et al. (Biochem. Biophys. Res. Commun. 196, 837-843, 1993). 3DG in the ultrafiltrate or the supernatant was conjugated with 2,3-diamino-naphthalene to produce a stable adduct which was then converted to a silyl ether and analyzed by GC/MS. The analyte was monitored by selected ion monitoring at an m/z of 295 and 306 and quantitated using an internal standard of [U-13C]3DG. Using this approach, 3DG levels in plasma deproteinized by ultrafiltration were found to be significantly elevated from 58.5 +/- 14 (SD) nM in normoglycemics to 98.5 +/- 34 (SD) nM in type I diabetics. When deproteinization of the plasma was carried out using ethanol, the levels of 3DG from normoglycemic plasma were similar to those reported by Niwa et al. (1710 +/- 750 (SD) nM). These results suggest that 3DG levels measured by ultrafiltration may represent the free circulating 3DG and those obtained by ethanol extraction may represent aform of 3DG bound to a macromolecule (presumbaly protein).

- by Paul Beisswenger
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- Ultrafiltration, Humans, Carbon Isotopes, Female

ABSTRACT We investigate the potential of ultraviolet spectroscopy (UV) to monitor cleaning of whey filtration membrane units. Based on sample collections in a full scale production environment two cases of cleaning monitoring by UV are evaluated. The first case demonstrates that UV can measure progress during both recirculation cleaning and the subsequent flushing of cleaning agents. The second case establishes that kinetics during the enzymatic cleaning step can be followed by UV and shows that different cleaning mechanisms are acting simultaneously. We also assess the detection limit for different whey components in a mixture design. Results show that UV in combination with partial least squares regression can quantify whey components down to between 10–20 ppm for whey protein, 5–9 ppm for whey fat, and 60–80 ppm for non-protein/fat solids.

- by Søren Balling Engelsen
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- Chemometrics, Food Engineering, Spectroscopy, Ultrafiltration
- by Mirna Gigante
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- Carbon Dioxide, Ultrafiltration, Intact polar lipids, Dairy
- by Asuman Yavuz
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- Ultrafiltration, Echocardiography, Heart Failure, Humans
- by stein hallan
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- Ultrafiltration, Humans, American, Clinical Sciences
- by Magnus Braide
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- Ultrafiltration, Heparin, Glucose, Animals

ABSTRACTTollund Man is one of the most famous Iron Age bog bodies due to his well-preserved head. Since he was unearthed in 1950 in Bjældskovdal, Denmark, he has been subjected to several scientific investigations, but until now no attempts to reconstruct his general diet through isotope analyses have been conducted. Furthermore, previous radiocarbon (14C) analyses have only been able to date him broadly to the 3rd–4th century BC. In this study, stable isotope measurements (δ13C, δ15N) on bone collagen from Tollund Man’s femur and rib showed that the diet of Tollund Man was terrestrial-based and that the crops he ate probably were grown on manured fields. Accelerator mass spectrometry (AMS) 14C dates were obtained on both the <30kDa and >30kDa fractions of ultrafiltered collagen. Results showed that the ultrafiltration removed contamination from older substances from the burial environment. The femur was dated to 2330±23 BP, the rib to 2322±30 BP. These dates statistically agr...

- by Marie Kanstrup
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- Archaeology, Prehistoric Archaeology, Geochemistry, Stable Isotope Analysis
- by Kiran Kekre
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- Chemical Engineering, Analytical Chemistry, Stability, Ultrafiltration
- by Richard Lueptow
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- Water, Carbon, Water Purification, Water Treatment
- by Francesco Ferella
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- Engineering, Arsenic, Time Use, Ultrafiltration
- by ming wu
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- Engineering, Wastewater Treatment, Ultrafiltration, Environmental Sciences
- by wim doyen
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- Engineering, Mass Transfer, Membrane Science, Scanning Electron Microscopy
- by Helmut Kroiss
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- Perfume, Activated Sludge, Multidisciplinary, Membrane Bioreactor Technology
- by Boris Koch
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- Engineering, Geology, Geochemistry, Oceanography
- by S. Tulipani
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- Chemical Engineering, Analytical Chemistry, Phospholipids, Ultrafiltration

Volume management is an integral component of the care of patients with acute kidney injury (AKI). Considerable controversy exists regarding the use of pharmacological agents for volume management. Although overt fluid overload is often seen in AKI and may prompt attention for the use of diuretics, often these agents are used in the absence of fluid retention. Over the last decade several new agents have become available for volume removal. We reviewed the literature on this topic and addressed four key questions for the appropriate utilization of these agents. These include the drug targets and mechanism of action of available agents; clinical goals and criteria for timing of intervention; adaptation of therapy for specific clinical settings and measures required for monitoring effectiveness and patient safety. This report details our current knowledge in this area, provides evidence-based clinical practice recommendations where appropriate, and formulates a research agenda to addr...

- by Ravindra Mehta and +1
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- Biomedical Engineering, Acute kidney injury, Ultrafiltration, Heart Failure

This work describes the development of a straightforward method for the determination of free docetaxel and paclitaxel in plasma. The separation of bound and unbound drug was performed with ultrafiltration. Different ultrafiltration devices were evaluated, especially regarding non-specific binding to the device. The most appropriate device for this application was selected and a procedure to counteract non-specific binding to the ultrafiltrate collection cup was developed. This consisted of a wash procedure with methyl t-butyl ether. A liquid/liquid extraction with methyl t-butyl ether was performed and samples were analysed with a previously developed liquid chromatography-tandem mass spectrometry procedure. The method used a Merck Purospher Star RP-18 column (55 mm x 2.0 mm, 3-microm particle size) and electrospray in the positive mode. A triple quadrupole instrument was used to monitor MRM transitions. Small modifications to this procedure were made to ensure adequate sensitivity. Within- and between-day reproducibility did not exceed 15% and accuracy ranged between 94.4 and 102.5%. The calibration range of the method was from 0.4 to 100 ng/ml both for paclitaxel and docetaxel. Finally, a fast and relatively simple method could be developed.

- by Kjell Mortier
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- Engineering, Technology, Mass Spectrometry, Ultrafiltration
- by Hanifah Lioe
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- Food Chemistry, Multidisciplinary, Ultrafiltration, Soybean

The binding of arsenite, As(III), and arsenate, As(V), by molecules in the intracellular compartment of rabbit erythrocytes has been studied by 1H- and 31P-NMR spectroscopy, uptake of 73As, and ultrafiltration experiments. For intact erythrocytes to which 0.1-0.4 mM arsenite was added, direct evidence was obtained for entry of 76% within 1/2 h and subsequent binding of As(III) by intracellular glutathione and induced changes in the hemoglobin structure (NMR), likely due to binding of As(III). These results were compared with the effect of addition of As(V) on intact erythrocytes and revealed that a smaller amount of As(V) (approximately 25%) enters the cells; the main fraction of As(V) enters the phosphate pathway, depletes ATP, and increases Pi. In contrast, As(III) did not affect the ATP level. Both 1H- and 31P-NMR data indicated striking differences between As(III) and As(V) behavior when incubated with rabbit erythrocytes. These differences were confirmed by 73As uptake and binding experiments. meso-2,3-Dimercaptosuccinic acid (DMSA), a dithiol ligand, released glutathione from its arsenite complexes in erythrocytes.

- by Marielle Delnomdedieu
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- Inorganic Chemistry, Organic Chemistry, Arsenic, Chemical
- by Amir Hamzah Sharaai
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- Water Treatment, Life Cycle Assessment, Ultrafiltration, Drinking Water
- by Markus Weiss
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- Algorithms, Dialysis, Ultrafiltration, Dogs

Tollund Man is one of the most famous Iron Age bog bodies due to his well-preserved head. Since he was unearthed in 1950 in Bjældskovdal, Denmark, he has been subjected to several scientific investigations, but until now no attempts to reconstruct his general diet through isotope analyses have been conducted. Furthermore, previous radiocarbon ( ¹⁴ C) analyses have only been able to date him broadly to the 3rd–4th century BC. In this study, stable isotope measurements (δ ¹³ C, δ ¹⁵ N) on bone collagen from Tollund Man’s femur and rib showed that the diet of Tollund Man was terrestrial-based and that the crops he ate probably were grown on manured fields. Accelerator mass spectrometry (AMS) ¹⁴ C dates were obtained on both the <30kDa and >30kDa fractions of ultrafiltered collagen. Results showed that the ultrafiltration removed contamination from older substances from the burial environment. The femur was dated to 2330±23 BP, the rib to 2322±30 BP. These dates statistically agree with a previously published AMS ¹⁴ C age on skin. By combining the new dates with the previous date of his skin it was possible to narrow down the age of Tollund Man to the period 405–380 cal BC (95.4% confidence interval).

- by Vasudeva Singh
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- Chemical Engineering, Algorithms, Food Science, Water
- by Sudip Chakraborty and +1
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- Water, Water Purification, Environmental Management, Multidisciplinary