Extracorporeal Ultrafiltration for Fluid Overload in Heart Failure

PubMed Central

Costanzo, Maria Rosa; Ronco, Claudio; Abraham, William T.; Agostoni, Piergiuseppe; Barasch, Jonathan; Fonarow, Gregg C.; Gottlieb, Stephen S.; Jaski, Brian E.; Kazory, Amir; Levin, Allison P.; Levin, Howard R.; Marenzi, Giancarlo; Mullens, Wilfried; Negoianu, Dan; Redfield, Margaret M.; Tang, W.H. Wilson; Testani, Jeffrey M.; Voors, Adriaan A.

2017-01-01

More than 1 million heart failure hospitalizations occur annually, and congestion is the predominant cause. Rehospitalizations for recurrent congestion portend poor outcomes independently of age and renal function. Persistent congestion trumps serum creatinine increases in predicting adverse heart failure outcomes. No decongestive pharmacological therapy has reduced these harmful consequences. Simplified ultrafiltration devices permit fluid removal in lower-acuity hospital settings, but with conflicting results regarding safety and efficacy. Ultrafiltration performed at fixed rates after onset of therapy-induced increased serum creatinine was not superior to standard care and resulted in more complications. In contrast, compared with diuretic agents, some data suggest that adjustment of ultrafiltration rates to patients’ vital signs and renal function may be associated with more effective decongestion and fewer heart failure events. Essential aspects of ultrafiltration remain poorly defined. Further research is urgently needed, given the burden of congestion and data suggesting sustained benefits of early and adjustable ultrafiltration. PMID:28494980

Ultrafiltration and modified ultrafiltration in pediatric open heart operations.

PubMed

Elliott, M J

1993-12-01

The capillary leak associated with cardiopulmonary bypass results in an increase in content of water in the tissues measurable by an increase in total body water after cardiac operation. Following work by Magilligan in the 1970s, ultrafiltration was introduced during bypass as a means of hemoconcentrating patients and potentially removing water from the tissues. Conventional methods proved inconsistent; thus, we modified the technique to ultrafilter the patients immediately after cessation of bypass. Modified ultrafiltration takes 10 minutes and results in an elevation of the on-bypass hematocrit to about 35% or 40%. In pilot studies comparing bypass in absence of ultrafiltration with conventional ultrafiltration and modified ultrafiltration, only the modified technique was seen reliably to reduce the elevation in total body water to only 4%, within a narrow range. Subsequent prospective studies confirmed the reduction in accumulation of total body water and also demonstrated a reduction in blood loss and in requirements for blood transfusion. Systolic blood pressure was observed to increase uniformly in all patients undergoing modified ultrafiltration. This effect was investigated and found to be associated with a marked increase in cardiac index, no change in systemic vascular resistance, a decrease in heart rate, and a marked decrease in pulmonary vascular resistance. Recently, we have demonstrated an increase in contractility and a decrease in myocardial wall volume. The modified technique of ultrafiltration has been employed successfully in more than 400 patients in our institution, and represents an excellent option for perioperative management of both accumulation of fluid in the tissues and hemodynamics after hypothermic bypass.

Metal Ion Interactions with Immunoglobulin G (IgG). 1. Preliminary Studies with Electron Paramagnetic Resonance (EPR) Spectroscopy and Ultrafiltration

DTIC Science & Technology

1978-12-12

EPR and ultrafiltration studies are recommceided to conduct luture metal ion- IgG binding research. Using Scatchard plots, bind.ng levels can be...of the binding sites can be best pursued by EPR and ultrafiltration using the fragments of IgG . This report noted some difference in the binding...immunoelectrophoresis, ultrafiltration, UV spectroscopy, atomic absorption spectroscopy, and electron paramagnetic resonance (EPR). IgG used ,- ,is non

Ultrafiltration for the Determination of Cu Complexed with Dissolved Organic Matters of Different Molecular Weight from a Eutrophic River, China.

PubMed

Li, Anding; Zhang, Yan; Zhou, Beihai; Xin, Kailing; Gu, Yingnan; Xu, Weijie; Tian, Jie

2018-05-21

The molecular weight of dissolved organic matter (DOM) is one of the essential factors controlling the properties of metal complexes. A continuous ultrafiltration experiment was designed to study the properties of Cu complexes with different molecular weights in a river before and after eutrophication. The results showed that the concentration of DOM increased from 26.47 to 38.20 mg/L during the eutrophication process, however, DOM was still dominated by the small molecular weight fraction before and after eutrophication. The amount of Cu-DOM complexes increased with the increasing of molecular weight, however, the amounts of DOM-Cu complexes before eutrophication were higher than those after eutrophication. This is because DOM contained more -COOH and -OH before eutrophication and these functional groups are the active sites complexed with Cu.

Automated electronic monitoring of circuit pressures during continuous renal replacement therapy: a technical report.

PubMed

Zhang, Ling; Baldwin, Ian; Zhu, Guijun; Tanaka, Aiko; Bellomo, Rinaldo

2015-03-01

Automated electronic monitoring and analysis of circuit pressures during continuous renal replacement therapy (CRRT) has the potential to predict failure and allow intervention to optimise function. Current CRRT machines can measure and store pressure readings for downloading into databases and for analysis. We developed a procedure to obtain such data at intervals of 1 minute and analyse them using the Prismaflex CRRT machine, and we present an example of such analysis. We obtained data on pressures obtained at intervals of 1 minute in a patient with acute kidney injury and sepsis treated with continuous haemofiltration at 2 L/hour of ultrafiltration and a blood flow of 200 mL/minute. Data analysis identified progressive increases in transmembrane pressure (TMP) and prefilter pressure (PFP) from time 0 until 33 hours or clotting. TMP increased from 104 mmHg to 313 mmHg and PFP increased from from 131 mmHg to 185 mmHg. Effluent pressure showed a progressive increase in the negative pressure applied to achieve ultrafiltration from 0 mmHg to -168 mmHg. The inflection point for such changes was also identified. Blood pathway pressures for access and return remained unchanged throughout. Automated electronic monitoring of circuit pressure during CRRT is possible and provides useful information on the evolution of circuit clotting.

Ozonation and ultrafiltration for the treatment of olive mill wastewaters: effect of key operating conditions and integration schemes.

PubMed

Martins, Rui C; Ferreira, Ana M; Gando-Ferreira, Licínio M; Quinta-Ferreira, Rosa M

2015-10-01

With the objective of reaching suitable techniques for olive mill wastewater treatment, ozonation and ultrafiltration were studied individually and combined. A continuous reactor was run for the treatment of a phenolic mixture mimicking an actual olive mill wastewater (OMW) by ozonation. The effect of the main operating parameters was analysed (pH, liquid flow rate and ozone inlet concentration). The increase of pH and ozone dose improved ozonation efficiency. As expected, the highest residence time led to higher steady-state degradation (35 % of chemical oxygen demand (COD) abatement). Even if the rise on ozone inlet gas concentration was able to remove COD in a higher extent, it should be taken into consideration that with the lowest oxidant load (15 g O3/m(3)), the maximum steady-state biochemical oxygen demand (BOD5)/COD ratio was reached which would reduce the process costs. These operating conditions (pH 9, 1 mL/min of liquid flow rate and 15 g O3/m(3)) were applied to an actual OMW leading to 80 % of phenolic content abatement and 12 % of COD removal at the steady state. Regarding ultrafiltration, it was concluded that the best total phenolic content (TPh) and COD abatement results (55 and 15 %) are attained for pH 9 and using a transmembrane pressure drop of 1 bar. Among the integration schemes that were tested, ultrafiltration followed by ozonation was able to reach 93 and 20 % of TPh and COD depletion, respectively. Moreover, this sequence led to an effluent with a BOD5/COD ratio of about 0.55 which means that it likely can be posteriorly refined in a municipal wastewater treatment plant.

[Comparison of essential oil enriched with ultrafiltration method and extraction method respectively from essential oil-in-water emulsion of Citri Reticulatae Pericarpium Viride by GC-MS].

PubMed

Yin, Ailing; Han, Zhifeng; Shen, Jie; Guo, Liwei; Cao, Guiping

2011-10-01

To study on the separation from essential oil-in-water emulsion of Citri Reticulatae Pericarpium Viride by ultrafiltration and acetoacetate extraction methods respectively, and the comparison of the oil yields and chemical compositions. Essential oil-in-water emulsion of Citri Reticulatae Pericarpium Viride was separated by ultrafiltration and acetoacetate extraction methods respectively, and the chemical compositions were analyzed and compared by GC-MS. Ultrafiltration method could enrich essential oil more and its chemical compositions were more similar to the essential oil prepared by steam distillation method. Ultrafiltration method is a good medium to separate essential oil from essential oil-in-water emulsion of Citri Reticulatae Pericarpium Viride.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shamsuddin Ilias

Fouling problems are perhaps the single most important reason for relatively slow acceptance of ultrafiltration in many areas of chemical and biological processing. To overcome the losses in permeate flux associated with concentration polarization and fouling in cross flow membrane filtration, we investigated the concept of flow reversal as a method to enhance membrane flux in ultrafiltration. Conceptually, flow reversal prevents the formation of stable hydrodynamic and concentration boundary layers at or near the membrane surface. Further more, periodic reversal of the flow direction of the feed stream at the membrane surface results in prevention and mitigation of membrane fouling.more » Consequently, these advantages are expected to enhance membrane flux significantly. A crossflow membrane filtration unit was designed and built to test the concept of periodic flow reversal for flux enhancement. The essential elements of the system include a crossflow hollow fiber membrane module integrated with a two-way valve to direct the feed flow directions. The two-way valve is controlled by a controller-timer for periodic reversal of flow of feed stream. Another important feature of the system is that with changing feed flow direction, the permeate flow direction is also changed to maintain countercurrent feed and permeate flows for enhanced mass transfer driving force (concentration difference). Three feed solutions (Bovine serum albumin (BSA), apple juice and citrus fruit pectin) were studied in crossflow membrane filtration. These solutes are well-known in membrane filtration for their fouling and concentration polarization potentials. Laboratory-scale tests on a hollow-fiber ultrafiltration membrane module using each of the feed solutes show that under flow reversal conditions, the permeate flux is significantly enhanced when compared with the conventional unidirectional flow. The flux enhancement is dramatic (by an order of magnitude) with increased feed concentration and operating transmembrane pressure. Thus, flow reversal technology seems an attractive alternative to mitigate fouling problem in crossflow membrane filtration.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shamsuddin Ilias

Fouling problems are perhaps the single most important reason for relatively slow acceptance of ultrafiltration in many areas of chemical and biological processing. To overcome the losses in permeate flux associated with concentration polarization and fouling in cross flow membrane filtration, we investigated the concept of flow reversal as a method to enhance membrane flux in ultrafiltration. Conceptually, flow reversal prevents the formation of stable hydrodynamic and concentration boundary layers at or near the membrane surface. Further more, periodic reversal of the flow direction of the feed stream at the membrane surface results in prevention and mitigation of membrane fouling.more » Consequently, these advantages are expected to enhance membrane flux significantly. A crossflow membrane filtration unit was designed and built to test the concept of periodic flow reversal for flux enhancement. The essential elements of the system include a crossflow hollow fiber membrane module integrated with a two-way valve to direct the feed flow directions. The two-way valve is controlled by a controller-timer for periodic reversal of flow of feed stream. Another important feature of the system is that with changing feed flow direction, the permeate flow direction is also changed to maintain countercurrent feed and permeate flows for enhanced mass transfer driving force (concentration difference). In this report, we report our application of Flow Reversal technique in clarification of apple juice containing pectin. The presence of pectin in apple juice makes the clarification process difficult and is believed to cause membrane fouling. Of all compounds found in apple juice, pectin is most often identified as the major hindrance to filtration performance. Based on our ultrafiltration experiments with apple juice, we conclude that under flow reversal conditions, the permeate flux is significantly enhanced when compared with the conventional unidirectional flow. Thus, flow reversal technology seems an attractive alternative to mitigate fouling problem in crossflow membrane filtration.« less

Ultrafiltrative deinking of flexographic ONP : the role of surfactants

Treesearch

Bradley H. Upton; Gopal A. Krishnagopalan; Said Abubakr

1999-01-01

Ultrafiltration is a potentially viable method of removing finely dispersed flexographic pigments from the deinking water loop. This work examines the effects of surface-active materials on ultrafiltration efficiency. A logarithmic relationship between permeate flax and pigment concentration was demonstrated at ink concentrations above 0.4%, permeation rates becoming...

A novel membrane based process to isolate photosystem-I membrane complex from spinach.

PubMed

Liu, Jianguo; Yin, Mengmeng; Wang, Meng; Zhang, Xuefang; Ge, Baosheng; Liu, Shuang; Lu, Jianren; Cui, Zhanfeng

2011-02-01

The isolation of photosystem-I (PS-I) from spinach has been conducted using ultrafiltration with 300 kDa molecular weight cut-off polyethersulfone membranes. The effects of ultrafiltration operating conditions on PS-I activity were optimized using parameter scanning ultrafiltration. These conditions included solution pH, ionic strength, stirring speed, and permeate flux. The effects of detergent (Triton X-100 and n-dodecyl-beta-D-maltoside) concentration on time dependent activity of PS-I were also studied using an O(2) electrode. Under optimized conditions, the PS-I purity obtained in the retentate was about 84% and the activity recovery was greater than 94% after ultrafiltration. To our knowledge, this is the first report of the isolation of a membrane protein using ultrafiltration alone.

Evaluation of Ultrafiltration for Spacecraft Water Reuse

NASA Technical Reports Server (NTRS)

Pickering, Karen D.; Wiesner, Mark R.

2001-01-01

Ultrafiltration is examined for use as the first stage of a primary treatment process for spacecraft wastewater. It is hypothesized that ultrafiltration can effectively serve as pretreatment for a reverse osmosis system, removing the majority of organic material in a spacecraft wastewater. However, it is believed that the interaction between the membrane material and the surfactant found in the wastewater will have a significant impact on the fouling of the ultrafiltration membrane. In this study, five different ultrafiltration membrane materials are examined for the filtration of wastewater typical of that expected to be produced onboard the International Space Station. Membranes are used in an unstirred batch cell. Flux, organic carbon rejection, and recovery from fouling are measured. The results of this evaluation will be used to select the most promising membranes for further study.

Errors in fluid balance with pump control of continuous hemodialysis.

PubMed

Roberts, M; Winney, R J

1992-02-01

The use of pumps both proximal and distal to the dialyzer during continuous hemodialysis provides control of dialysate and ultrafiltration flow rates, thereby reducing nursing time. However, we had noted unexpected severe extracellular fluid depletion suggesting that errors in pump delivery may be responsible. We measured in vitro the operation of various pumps under conditions similar to continuous hemodialysis. Fluid delivery of peristaltic and roller pumps varied with how the tubing set was inserted in the pump. Piston and peristaltic pumps with dedicated pump segments were more accurate. Pumps should be calibrated and tested under conditions simulating continuous hemodialysis prior to in vivo use.

Membraneless water filtration using CO2

NASA Astrophysics Data System (ADS)

Shin, Sangwoo; Shardt, Orest; Warren, Patrick B.; Stone, Howard A.

2017-05-01

Water purification technologies such as microfiltration/ultrafiltration and reverse osmosis utilize porous membranes to remove suspended particles and solutes. These membranes, however, cause many drawbacks such as a high pumping cost and a need for periodic replacement due to fouling. Here we show an alternative membraneless method for separating suspended particles by exposing the colloidal suspension to CO2. Dissolution of CO2 into the suspension creates solute gradients that drive phoretic motion of particles. Due to the large diffusion potential generated by the dissociation of carbonic acid, colloidal particles move either away from or towards the gas-liquid interface depending on their surface charge. Using the directed motion of particles induced by exposure to CO2, we demonstrate a scalable, continuous flow, membraneless particle filtration process that exhibits low energy consumption, three orders of magnitude lower than conventional microfiltration/ultrafiltration processes, and is essentially free from fouling.

Membraneless water filtration using CO2

PubMed Central

Shin, Sangwoo; Shardt, Orest; Warren, Patrick B.; Stone, Howard A.

2017-01-01

Water purification technologies such as microfiltration/ultrafiltration and reverse osmosis utilize porous membranes to remove suspended particles and solutes. These membranes, however, cause many drawbacks such as a high pumping cost and a need for periodic replacement due to fouling. Here we show an alternative membraneless method for separating suspended particles by exposing the colloidal suspension to CO2. Dissolution of CO2 into the suspension creates solute gradients that drive phoretic motion of particles. Due to the large diffusion potential generated by the dissociation of carbonic acid, colloidal particles move either away from or towards the gas–liquid interface depending on their surface charge. Using the directed motion of particles induced by exposure to CO2, we demonstrate a scalable, continuous flow, membraneless particle filtration process that exhibits low energy consumption, three orders of magnitude lower than conventional microfiltration/ultrafiltration processes, and is essentially free from fouling. PMID:28462929

Heterogeneous asymmetric recombinase polymerase amplification (haRPA) for rapid hygiene control of large-volume water samples.

PubMed

Elsäßer, Dennis; Ho, Johannes; Niessner, Reinhard; Tiehm, Andreas; Seidel, Michael

2018-04-01

Hygiene of drinking water is periodically controlled by cultivation and enumeration of indicator bacteria. Rapid and comprehensive measurements of emerging pathogens are of increasing interest to improve drinking water safety. In this study, the feasibility to detect bacteriophage PhiX174 as a potential indicator for virus contamination in large volumes of water is demonstrated. Three consecutive concentration methods (continuous ultrafiltration, monolithic adsorption filtration, and centrifugal ultrafiltration) were combined to concentrate phages stepwise from 1250 L drinking water into 1 mL. Heterogeneous asymmetric recombinase polymerase amplification (haRPA) is applied as rapid detection method. Field measurements were conducted to test the developed system for hygiene online monitoring under realistic conditions. We could show that this system allows the detection of artificial contaminations of bacteriophage PhiX174 in drinking water pipelines. Copyright © 2018 Elsevier Inc. All rights reserved.

Evolution of phospholipid contents during the production of quark cheese from buttermilk.

PubMed

Ferreiro, T; Martínez, S; Gayoso, L; Rodríguez-Otero, J L

2016-06-01

We report the evolution of phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylcholine (PC), phosphatidylserine (PS), and sphingomyelin (SM) contents during the production of quark cheese from buttermilk by successive ultrafiltration concentration, enrichment with cream, concurrent homogenization and pasteurization, fermentative coagulation, and separation of quark from whey by further ultrafiltration. Buttermilk is richer than milk itself in phospholipids that afford desirable functional and technological properties, and is widely used in dairy products. To investigate how phospholipid content is affected by end-product production processes such as ultrafiltration, homogenization, pasteurization or coagulation, we measured the phospholipids at several stages of each of 5 industrial-scale quark cheese production runs. In each run, 10,000L of buttermilk was concentrated to half volume by ultrafiltration, enriched with cream, homogenized, pasteurized, inoculated with lactic acid bacteria, incubated to coagulation, and once more concentrated to half volume by ultrafiltration. Phospholipid contents were determined by HPLC with evaporative light scattering detection in the starting buttermilk, concentrated buttermilk, ultrafiltrate, cream-enriched concentrated buttermilk (both before and after concurrent homogenization and pasteurization), coagulate, and quark, and also in the rinsings obtained when the ultrafiltration equipment was washed following initial concentration. The average phospholipid content of buttermilk was approximately 5 times that of milk, and the phospholipid content of buttermilk fat 26 to 29 times that of milk fat. Although phospholipids did not cross ultrafiltration membranes, significant losses occurred during ultrafiltration (due to retention on the membranes) and during the homogenization and pasteurization process. During coagulation, however, phospholipid content rose, presumably as a consequence of the proliferation of the inoculated lactic acid bacteria. In spite of these changes in total phospholipid content, the relative proportions of the phospholipids studied remain fairly stable throughout quark production (PE>PC>SM>PS>PI) and similar to those found in the milk of the region, except that SM content was lower than in milk. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Carbon Nanotubules: Building Blocks for Nanometer-Scale Engineering

NASA Technical Reports Server (NTRS)

Sinnott, Susan B.

1999-01-01

The proposed work consisted of two projects: the investigation of fluid permeation and diffusion through ultrafiltration membranes composed of carbon nanotubules and the design and study of molecular transistors composed of nanotubules. I will outline the progress made on each project and also discuss additional projects, one of which is a continuation of work supported by an 1995-1996 NASA Ames Computer grant.

Increased Intracranial Pressure during Hemodialysis in a Patient with Anoxic Brain Injury.

PubMed

Lund, Anton; Damholt, Mette B; Strange, Ditte G; Kelsen, Jesper; Møller-Sørensen, Hasse; Møller, Kirsten

2017-01-01

Dialysis disequilibrium syndrome (DDS) is a serious neurological complication of hemodialysis, and patients with acute brain injury are at increased risk. We report a case of DDS leading to intracranial hypertension in a patient with anoxic brain injury and discuss the subsequent dialysis strategy. A 13-year-old girl was admitted after prolonged resuscitation from cardiac arrest. Computed tomography (CT) revealed an inferior vena cava aneurysm and multiple pulmonary emboli as the likely cause. An intracranial pressure (ICP) monitor was inserted, and, on day 3, continuous renal replacement therapy (CRRT) was initiated due to acute kidney injury, during which the patient developed severe intracranial hypertension. CT of the brain showed diffuse cerebral edema. CRRT was discontinued, sedation was increased, and hypertonic saline was administered, upon which ICP normalized. Due to persistent hyperkalemia and overhydration, ultrafiltration and intermittent hemodialysis were performed separately on day 4 with a small dialyzer, low blood and dialysate flow, and high dialysate sodium content. During subsequent treatments, isolated ultrafiltration was well tolerated, whereas hemodialysis was associated with increased ICP necessitating frequent pauses or early cessation of dialysis. In patients at risk of DDS, hemodialysis should be performed with utmost care and continuous monitoring of ICP should be considered.

A multiphase approach to model ultrafiltration of deformable colloids

NASA Astrophysics Data System (ADS)

Haribabu, Malavika; Dunstan, Dave; Davidson, Malcolm; Harvie, Dalton

2017-11-01

Ultrafiltration (UF) is widely used in the dairy industry to fractionate and concentrate proteins, during the manufacture of milk protein concentrate and cheese. The protein build-up, comprising casein micelles (CM) and whey proteins, at the membrane surface during UF increases the resistance of the membrane system, thereby decreasing the performance of the process unit. CM have a complex structure that hydrodynamically behaves as a hard-sphere when dilute, but deforms beyond the random packing limit, forming a shear-thinning gel. This study employs a mixture model, based on the mixture phase continuity, Navier-Stokes equations, and solids continuity equation, to predict the solid concentration and velocity distribution during UF of CM. Micelle deformation is modelled as a function of volume fraction and dependent on its elastic modulus and particle size. The effect of deformation on gel permeability is implemented via Happel's permeability for hard spheres. Under crossflow conditions, the gel thickness is observed to increase along the membrane length, followed by a decrease towards the end of the membrane, resulting in an increase in flux at the latter section of the membrane. This study demonstrates that the membrane end-effects are important in determining UF performance.

Quantification and clinical application of carboplatin in plasma ultrafiltrate.

PubMed

Downing, Kim; Jensen, Berit Packert; Grant, Sue; Strother, Matthew; George, Peter

2017-05-10

Carboplatin is a chemotherapy drug used in a variety of cancers with the primary toxicity being exposure-dependant myelosuppression. We present the development and validation of a simple, robust inductively coupled plasma mass spectrometry (ICP-MS) method to measure carboplatin in plasma ultrafiltrate. Plasma ultrafiltrates samples were prepared using Amicon Ultra 30,000da cut-off filters and then diluted with ammonia EDTA before ICP-MS analysis. The assay was validated in the range 0.19-47.5mg/L carboplatin in ultrafiltrate. The assay was linear (r 2 >0.9999), accurate (<6% bias, 12% bias at LLOQ) and precise (intra- and inter-day precision of <3% coefficient of variation). No matrix effects were observed between plasma ultrafiltrate and aqueous platinum calibrators and recovery was complete. The assay was applied to 10 clinical samples from patients receiving carboplatin. Incurred sample reanalysis showed reproducible values over 3 analysis days (<6% CV). As plasma stability prior to ultrafiltration has been a major concern in previous clinical studies this was studied extensively at room temperature (22°C) over 24h. Carboplatin was found to be stable in both spiked plasma (n=3) and real patient samples (n=10) at room temperature for up to 8h before ultrafiltration. This makes routine measurement of carboplatin concentrations in clinical settings feasible. Copyright © 2017 Elsevier B.V. All rights reserved.

Hollow-fiber ultrafiltration of Cryptosporidium parvum oocysts from a wide variety of 10-L surface water samples.

PubMed

Kuhn, Ryan C; Oshima, Kevin H

2002-06-01

An optimized hollow-fiber ultrafiltration system (50 000 MWCO) was developed to concentrate Cryptosporidium oocysts from 10-L samples of environmental water. Seeded experiments were conducted using a number of surface-water samples from the southwestern U.S.A. and source water from four water districts with histories of poor oocyst recovery. Ultrafiltration produced a mean recovery of 47.9% from 19 water samples (55.3% from 39 individual tests). We also compared oocyst recoveries using the hollow-fiber ultrafiltration system with those using the Envirochek filter. In limited comparison tests, the hollow-fiber ultrafiltration system produced recoveries similar to those of the Envirochek filter (hollow fiber, 74.1% (SD = 2.8); Envirochek, 71.9% (SD = 5.2)) in low-turbidity (3.9 NTU) samples and performed better than the Envirochek filter in high-turbidity (159.0 NTU) samples (hollow fiber, 27.5%; Envirochek, 0.4%). These results indicate that hollow-fiber ultrafiltration can efficiently recover oocysts from a wide variety of surface waters and may be a cost-effective alternative for concentrating Cryptosporidium from water, given the reusable nature of the filter.

The Effect of Cellulose Acetate Concentration from Coconut Nira on Ultrafiltration Membrane Characters

NASA Astrophysics Data System (ADS)

Vaulina, E.; Widyaningsih, S.; Kartika, D.; Romdoni, M. P.

2018-04-01

Cellulose acetate is one of material in produce ultrafiltration membrane. Many efforts have been done to produce cellulose acetate from natural product to replace commercial one. In this research, ultrafiltration membrane has been produced from coconut flower water (nira). Ultrafiltration membrane is widely used in separation processes. This research aims to determine the characteristics of ultrafiltration membrane at a various concentration of cellulose acetate. The ultrafiltration membrane is conducted by phase inversion method at various concentration of cellulose acetate. The cellulose acetate concentration was 20%, 23% and 25% (w/w) with formamide as additives. The results showed that the greater the concentration of cellulose acetate, the smaller the flux value. The highest flux was a membrane with 20% cellulose acetate concentration with water flux value 55.34 L/(m2. h). But the greater the concentration of cellulose acetate the greater the rejection. The highest rejection value was on a membrane with 25% cellulose acetate concentration of 82.82%. While from the tensile strength test and the pore size analysis, the greater the cellulose acetate concentration the greater the tensile strength and the smaller the pore size

Residual blood processing by centrifugation, cell salvage or ultrafiltration in cardiac surgery: effects on clinical hemostatic and ex-vivo rheological parameters.

PubMed

Vonk, Alexander B; Muntajit, Warayouth; Bhagirath, Pranav; van Barneveld, Laurentius J; Romijn, Johannes W; de Vroege, Roel; Boer, Christa

2012-10-01

The study compared the effects of three blood concentration techniques after cardiopulmonary bypass on clinical hemostatic and ex-vivo rheological parameters. Residual blood of patients undergoing elective cardiac surgery was processed by centrifugation, cell salvage or ultrafiltration, and retransfused (n = 17 per group). Study parameters included blood loss, (free) hemoglobin, hematocrit, fibrinogen and erythrocyte aggregation, deformability and 2,3-diphosphoglycerate content. Patient characteristics were similar between groups. Ultrafiltration was associated with the highest weight of the transfusion bag [649 ± 261 vs. 320 ± 134 g (centrifugation) and 391 ± 158 g (cell salvage); P < 0.01]. Cell salvage resulted in the lowest hemolysis levels in the transfusion bag. Retransfusion of cell saver blood induced the largest gain in postoperative patient hemoglobin levels when compared to centrifugation and ultrafiltration, and was associated with the largest increase in 2,3-diphosphoglycerate when compared to ultrafiltration (Δ2,3-diphosphoglycerate 1.34 ± 1.92 vs. -0.77 ± 1.56 mmol/l; P = 0.03). Cell salvage is superior with respect to postoperative hemoglobin gain and washout of free hemoglobin when compared to centrifugation or ultrafiltration.

Peritoneal fluid transport in CAPD patients with different transport rates of small solutes.

PubMed

Sobiecka, Danuta; Waniewski, Jacek; Weryński, Andrzej; Lindholm, Bengt

2004-01-01

Continuous ambulatory peritoneal dialysis (CAPD) patients with high peritoneal solute transport rate often have inadequate peritoneal fluid transport. It is not known whether this inadequate fluid transport is due solely to a too rapid fall of osmotic pressure, or if the decreased effectiveness of fluid transport is also a contributing factor. To analyze fluid transport parameters and the effectiveness of dialysis fluid osmotic pressure in the induction of fluid flow in CAPD patients with different small solute transport rates. 44 CAPD patients were placed in low (n = 6), low-average (n = 13), high-average (n = 19), and high (n = 6) transport groups according to a modified peritoneal equilibration test (PET). The study involved a 6-hour peritoneal dialysis dwell with 2 L 3.86% glucose dialysis fluid for each patient. Radioisotopically labeled serum albumin was added as a volume marker.The fluid transport parameters (osmotic conductance and fluid absorption rate) were estimated using three mathematical models of fluid transport: (1) Pyle model (model P), which describes ultrafiltration rate as an exponential function of time; (2) model OS, which is based on the linear relationship of ultrafiltration rate and overall osmolality gradient between dialysis fluid and blood; and (3) model G, which is based on the linear relationship between ultrafiltration rate and glucose concentration gradient between dialysis fluid and blood. Diffusive mass transport coefficients (K(BD)) for glucose, urea, creatinine, potassium, and sodium were estimated using the modified Babb-Randerson-Farrell model. The high transport group had significantly lower dialysate volume and glucose and osmolality gradients between dialysate and blood, but significantly higher K(BD) for small solutes compared with the other transport groups. Osmotic conductance, fluid absorption rate, and initial ultrafiltration rate did not differ among the transport groups for model OS and model P. Model G yielded unrealistic values of fluid transport parameters that differed from those estimated by models OS and P. The K(BD) values for small solutes were significantly different among the groups, and did not correlate with fluid transport parameters for model OS. The difference in fluid transport between the different transport groups was due only to the differences in the rate of disappearance of the overall osmotic pressure of the dialysate, which was a combined result of the transport rate of glucose and other small solutes. Although the glucose gradient is the major factor influencing ultrafiltration rate, other solutes, such as urea, are also of importance. The counteractive effect of plasma small solutes on transcapillary ultrafiltration was found to be especially notable in low transport patients. Thus, glucose gradient alone should not be considered the only force that shapes the ultrafiltration profile during peritoneal dialysis. We did not find any correlations between diffusive mass transport coefficients for small solutes and fluid transport parameters such as osmotic conductance or fluid and volume marker absorption. We may thus conclude that the pathway(s) for fluid transport appears to be partly independent from the pathway(s) for small solute transport, which supports the hypothesis of different pore types for fluid and solute transport.

ETV REPORT - PHYSICAL REMOVAL OF CRYPTOSPORIDIUM OOCYSTS AND GIARDIA CYSTS IN DRINKING WATER, LEOPOLD MEMBRANE SYSTEMS ULTRABAR ULTRAFILTRATION SYSTEM WITH 60 INCH MARK III ELEMENT AT PITTSBURG, PA - NSF/00/10/EPADW395

EPA Science Inventory

Verification testing of the Leopold Ultrabar Mark III Ultrafiltration Systems was conducted from February 3-March9, 1999. The performance claim evaluated during field testing of the Leopold Ultrabar Mark III Ultrafiltration system was that the system is capable of a minimum 3 log...

[Investigation on the phenomena of bacteria exceeding standards in rural pit water treated by ultrafiltration membrane].

PubMed

Yue, Yinling; Zhang, Lan; Ling, Bo

2011-11-01

To investigate the phenomenon of bacteria exceeding standards in rural pit water, which was intermittently operated by water pump equipped with ultrafiltration membrane, and to explore the solutions. Polyvinyl chloride (PVC) alloy capillary membranes combined with UV, disinfectant, one-way valve, water-seal, high water level-water tank and direct outlet were tested. The operation on water treatment was intermittent, simulating the ways of treating pit water in the rural. The combination modes of ultrafiltration membrane with UV, disinfectant and high water level-water tank are valid in solving the problem of high turbidity and microorganism of pit water stored in cellars, the quality of effluents was consistent with the requirements of the national standards. While the combination modes of ultrafiltration membrane with one-way valve or water-seal were less desirable, more bacteria in treated water than raw water were observed because of bacteria breeding on the membrane component. In order to avoid excessive bacteria in filtered pit water caused by intermittent operation, it is recommended that for the pit water in high water level water tanks, the ultrafiltration membranes should be cleaned with disinfectants on a regular basis. The effluent pit water from underground cellars should be disinfected with UV after ultrafiltration.

Identification of the Allergenic Ingredients in Reduning Injection by Ultrafiltration and High-Performance Liquid Chromatography.

PubMed

Wang, Fang; Li, Cun-yu; Zheng, Yun-feng; Li, Hong-yang; Xiao, Wei; Peng, Guo-ping

2016-01-01

Reduning injection is a traditional Chinese medicine injection which has multiple functions such as clearing heat, dispelling wind, and detoxification. Although Reduning injection was widely utilized, reports of its allergenicity emerged one after another. However, there is little research on its allergenic substances. The aim of this study is to evaluate the sensitization of Reduning injection and explore the underlying cause of the anaphylactic reaction. The main ingredients in Reduning injection were analyzed before and after ultrafiltration. Ultrafiltrate Reduning injection, unfiltered Reduning injection, egg albumin, Tween-80, and nine effective components in Reduning injection were utilized to sensitize guinea pigs. The serum 5-hydroxytryptamine level was used to assess the sensitization effect of Reduning injection. We found a significant decrease in Tween-80 content comparing to other components in the injection after ultrafiltration. Unfiltered Reduning injection, Tween-80, chlorogenic acid, and cryptochlorogenin acid caused remarkable anaphylactoid reaction on guinea pigs while ultrafiltration Reduning resulted in a significantly lower degree of sensitization. Our results suggest that ultrafiltration could significantly reduce the sensitization of Reduning injection, which is likely due to the decrease of Tween-80. We also conjectured that the form of chlorogenic acid and cryptochlorogenin acid within the complex solution mixture may also affect the sensitizing effect.

Increased Intracranial Pressure during Hemodialysis in a Patient with Anoxic Brain Injury

PubMed Central

Damholt, Mette B.; Strange, Ditte G.; Kelsen, Jesper; Møller-Sørensen, Hasse; Møller, Kirsten

2017-01-01

Dialysis disequilibrium syndrome (DDS) is a serious neurological complication of hemodialysis, and patients with acute brain injury are at increased risk. We report a case of DDS leading to intracranial hypertension in a patient with anoxic brain injury and discuss the subsequent dialysis strategy. A 13-year-old girl was admitted after prolonged resuscitation from cardiac arrest. Computed tomography (CT) revealed an inferior vena cava aneurysm and multiple pulmonary emboli as the likely cause. An intracranial pressure (ICP) monitor was inserted, and, on day 3, continuous renal replacement therapy (CRRT) was initiated due to acute kidney injury, during which the patient developed severe intracranial hypertension. CT of the brain showed diffuse cerebral edema. CRRT was discontinued, sedation was increased, and hypertonic saline was administered, upon which ICP normalized. Due to persistent hyperkalemia and overhydration, ultrafiltration and intermittent hemodialysis were performed separately on day 4 with a small dialyzer, low blood and dialysate flow, and high dialysate sodium content. During subsequent treatments, isolated ultrafiltration was well tolerated, whereas hemodialysis was associated with increased ICP necessitating frequent pauses or early cessation of dialysis. In patients at risk of DDS, hemodialysis should be performed with utmost care and continuous monitoring of ICP should be considered. PMID:28409034

High performance concentration method for viruses in drinking water.

PubMed

Kunze, Andreas; Pei, Lu; Elsässer, Dennis; Niessner, Reinhard; Seidel, Michael

2015-09-15

According to the risk assessment of the WHO, highly infectious pathogenic viruses like rotaviruses should not be present in large-volume drinking water samples of up to 90 m(3). On the other hand, quantification methods for viruses are only operable in small volumes, and presently no concentration procedure for processing such large volumes has been reported. Therefore, the aim of this study was to demonstrate a procedure for processing viruses in-line of a drinking water pipeline by ultrafiltration (UF) and consecutive further concentration by monolithic filtration (MF) and centrifugal ultrafiltration (CeUF) of viruses to a final 1-mL sample. For testing this concept, the model virus bacteriophage MS2 was spiked continuously in UF instrumentation. Tap water was processed in volumes between 32.4 m(3) (22 h) and 97.7 m(3) (72 h) continuously either in dead-end (DE) or cross-flow (CF) mode. Best results were found by DE-UF over 22 h. The concentration of MS2 was increased from 4.2×10(4) GU/mL (genomic units per milliliter) to 3.2×10(10) GU/mL and from 71 PFU/mL to 2×10(8) PFU/mL as determined by qRT-PCR and plaque assay, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

Protein aggregation under high concentration/density state during chromatographic and ultrafiltration processes.

PubMed

Arakawa, Tsutomu; Ejima, Daisuke; Akuta, Teruo

2017-02-01

Local transient high protein concentration or high density condition can occur during processing of protein solutions. Typical examples are saturated binding of proteins during column chromatography and high protein concentration on the semi-permeable membrane during ultrafiltration. Both column chromatography and ultrafiltration are fundamental technologies, specially for production of pharmaceutical proteins. We summarize here our experiences related to such high concentration conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

The Mutual Relationship Between Peritonitis and Peritoneal Transport.

PubMed

van Esch, Sadie; van Diepen, Anouk T N; Struijk, Dirk G; Krediet, Raymond T

2016-01-01

♦ Preservation of the peritoneum is required for long-term peritoneal dialysis (PD). We investigated the effect of multiple peritonitis episodes on peritoneal transport. ♦ Prospectively collected data from 479 incident PD patients treated between 1990 and 2010 were analyzed, using strict inclusion criteria: follow-up of at least 3 years with the availability of a Standard Peritoneal Permeability Analysis (SPA) in the first year after start of PD and within the third year of PD, without peritonitis preceding the first SPA. For the purpose of the study, we only included patients who remained peritonitis-free (n = 28) or who experienced 3 or more peritonitis episodes (n = 16). ♦ At baseline the groups were similar with regard to small solute and fluid transport. However, the frequent peritonitis group had lower peritoneal protein clearances compared to the no peritonitis group, resulting in lower dialysate concentrations of proteins: albumin 196.5 mg/L vs 372.5 mg/L, IgG 36.4 mg/L vs 65.0 mg/L, and α-2-macroglobulin (A2M) 1.9 mg/L vs 3.6 mg/L, p <0.01. No differences in serum concentrations were present. A comparison between the transport slopes over time in both groups showed a positive time trend of mass transfer area coefficient (MTAC) creatinine (p = 0.03) and glucose absorption (p = 0.09) and a negative trend of transcapillary ultrafiltration (p = 0.06), when compared to the no peritonitis group. Frequent peritonitis did not affect free water transport. ♦ Slow initial peritoneal transport rates of serum proteins result in lower dialysate concentrations, and likely a lower opsonic activity, which is a risk factor for peritonitis. Patients with frequent peritonitis show an increase in small solute transport and a concomitant decrease of ultrafiltration. In long-term peritonitis-free PD patients, small solute transport decreased, while ultrafiltration increased. This suggests that frequent peritonitis leads to an increase of the vascular peritoneal surface area without all the structural membrane alterations that may develop after long-term PD. Copyright © 2016 International Society for Peritoneal Dialysis.

The Mutual Relationship Between Peritonitis and Peritoneal Transport

PubMed Central

van Esch, Sadie; van Diepen, Anouk T.N.; Struijk, Dirk G.; Krediet, Raymond T.

2016-01-01

♦ Background: Preservation of the peritoneum is required for long-term peritoneal dialysis (PD). We investigated the effect of multiple peritonitis episodes on peritoneal transport. ♦ Methods: Prospectively collected data from 479 incident PD patients treated between 1990 and 2010 were analyzed, using strict inclusion criteria: follow-up of at least 3 years with the availability of a Standard Peritoneal Permeability Analysis (SPA) in the first year after start of PD and within the third year of PD, without peritonitis preceding the first SPA. For the purpose of the study, we only included patients who remained peritonitis-free (n = 28) or who experienced 3 or more peritonitis episodes (n = 16). ♦ Results: At baseline the groups were similar with regard to small solute and fluid transport. However, the frequent peritonitis group had lower peritoneal protein clearances compared to the no peritonitis group, resulting in lower dialysate concentrations of proteins: albumin 196.5 mg/L vs 372.5 mg/L, IgG 36.4 mg/L vs 65.0 mg/L, and α-2-macroglobulin (A2M) 1.9 mg/L vs 3.6 mg/L, p <0.01. No differences in serum concentrations were present. A comparison between the transport slopes over time in both groups showed a positive time trend of mass transfer area coefficient (MTAC) creatinine (p = 0.03) and glucose absorption (p = 0.09) and a negative trend of transcapillary ultrafiltration (p = 0.06), when compared to the no peritonitis group. Frequent peritonitis did not affect free water transport. ♦ Conclusions: Slow initial peritoneal transport rates of serum proteins result in lower dialysate concentrations, and likely a lower opsonic activity, which is a risk factor for peritonitis. Patients with frequent peritonitis show an increase in small solute transport and a concomitant decrease of ultrafiltration. In long-term peritonitis-free PD patients, small solute transport decreased, while ultrafiltration increased. This suggests that frequent peritonitis leads to an increase of the vascular peritoneal surface area without all the structural membrane alterations that may develop after long-term PD. PMID:25395498

Making equipment to process paddy water for providing drinking water by using Ozone-UVC& Ultrafiltration

NASA Astrophysics Data System (ADS)

Styani, E.; Dja'var, N.; Irawan, C.; Hanafi

2018-01-01

This study focuses on making equipment which is useful to process paddy water to be consumable as drinking water by using ozone-UVC and ultrafiltration. The equipment which is made by the process of ozone-UVC and ultrafiltration or reverse osmosis is driven by electric power generated from solar panels. In the experiment, reverse osmosis system with ozone-UVC reactor proves to be good enough in producing high quality drinking water.

Limitations of salivary and blood cortisol determinations in pigs.

PubMed

Blackshaw, J K; Blackshaw, A W

1989-01-01

Blood and saliva samples were taken from groups of pigs maintained in intensive conditions. Multiple samples were taken from two unrestrained pregnant sows fitted with jugular cannulae. Single samples were taken from groups (mixed gilts and entire males; 70-90 kg) which were lightly exercised (7) or restrained (12). The rate of salivary secretion was low and collection of adequate samples took 5 min; in a number of pigs no saliva could be obtained. In order to stimulate salivary secretion, pigs (70-80 kg) were injected with pilocarpine nitrate (25 mg, subcutaneous) which produced a copious flow of saliva persisting for at least 15 min. Resting sows had higher mean levels of cortisol in plasma, ultrafiltrate and saliva than the other groups, which did not differ from each other. Within the pilocarpine group, males had a higher ultrafiltrate level of cortisol than females. In most instances salivary cortisol was significantly greater than ultrafiltrate cortisol. Ultrafiltrate and plasma cortisol were highly correlated (r = 0.883) but this correlation was low in the presence of pilocarpine (r = 0.260). Salivary cortisol was poorly correlated with either plasma (r = 0.167) or ultrafiltrate cortisol (r = 0.278) and the correlation with plasma was even lower following the administration of pilocarpine (r = 0.086). It was concluded that salivary estimates of cortisol in the pig were not usefully correlated with levels of ultrafiltrate (free) cortisol.

Fouling mechanism in ultrafiltration of vegetable oil

NASA Astrophysics Data System (ADS)

Ariono, D.; Wardani, A. K.; Widodo, S.; Aryanti, Putu T. P.; Wenten, I. G.

2018-03-01

Energy efficient and cost-effective separation of impurities from vegetable oil is a great challenge for vegetable oil processing. Several technologies have been developed, including pressurized membrane, chemical treatment, and chemical free separation methods. Among those technologies, ultrafiltration membrane is one of the most attractive processes with low operating pressure and temperature. In this work, hydrophobic polypropylene ultrafiltration membrane was used to remove impurities such as non-dissolved solids from palm kernel oil. Unfortunately, the hydrophobicity of polypropylene membrane leads to significant impact on the reduction of permeate flux due to membrane fouling. This fouling is associated with the accumulation of substances on the membrane surface or within the membrane pores. For better understanding, fouling mechanism that occurred during palm kernel oil ultrafiltration using hydrophobic polypropylene membrane was investigated. The effect of trans-membrane pressure and feed temperature on fouling mechanism was also studied. The result showed that cake formation became the dominant fouling mechanism up to 50 min operation of palm kernel oil ultrafiltration. Furthermore, the fouling mechanism was not affected by the increase of trans-membrane pressure and feed temperature.

Ultrafiltration by a compacted clay membrane-II. Sodium ion exclusion at various ionic strengths

USGS Publications Warehouse

Hanshaw, B.B.; Coplen, T.B.

1973-01-01

Several recent laboratory studies and field investigations have indicated that shales and compacted clay minerals behave as semipermeable membranes. One of the properties of semipermeable membranes is to retard or prevent the passage of charged ionic species through the membrane pores while allowing relatively free movement of uncharged species. This phenomenon is termed salt filtering, reverse osmosis, or ultrafiltration. This paper shows how one can proceed from the ion exchange capacity of clay minerals and, by means of Donnan membrane equilibrium concept and the Teorell-Meyer-Siever theory, develop a theory to explain why and to what extent ultrafiltration occurs when solutions of known concentration are forced to flow through a clay membrane. Reasonable agreement between theory and laboratory results were found. The concentration of the ultrafiltrate was always greater than predicted because of uncertainty in values of some parameters in the equations. Ultrafiltration phenomena may be responsible for the formation of some subsurface brines and mineral deposits. The effect should also be taken into consideration in any proposal for subsurface waste emplacement in an environment containing large quantities of clay minerals. ?? 1973.

21 CFR 177.2910 - Ultra-filtration membranes.

Code of Federal Regulations, 2014 CFR

2014-04-01

.... 1314-36-9). (4) Ultrafiltration membranes that consist of a microporous poly(vinylidene fluoride... gallons of potable water prior to their first use in contact with food. (g) Acrylonitrile copolymers...

The evaluation of hollow-fiber ultrafiltration and celite concentration of enteroviruses, adenoviruses and bacteriophage from different water matrices

EPA Pesticide Factsheets

The data to support the evaluation of hollow-fiber ultrafiltration and celite concentration of enteroviruses, adenoviruses and bacteriophage from different water matricesThis dataset is associated with the following publication:Rhodes , E., E. Huff, D. Hamilton, and J. Jones. The evaluation of hollow-fiber ultrafiltration and celite concentration of enteroviruses, adenoviruses and bacteriophage from different water matrices. JOURNAL OF VIROLOGICAL METHODS. Elsevier Science Ltd, New York, NY, USA, 228(2): 31-38, (2016).

Rationale and design of the Aquapheresis Versus Intravenous Diuretics and Hospitalization for Heart Failure (AVOID-HF) trial.

PubMed

Costanzo, Maria Rosa; Negoianu, Daniel; Fonarow, Gregg C; Jaski, Brian E; Bart, Bradley A; Heywood, J Thomas; Nabut, Jose L; Schollmeyer, Michael P

2015-09-01

In patients hospitalized with acutely decompensated heart failure, unresolved signs and symptoms of fluid overload have been consistently associated with poor outcomes. Regardless of dosing and type of administration, intravenous loop diuretics have not reduced heart failure events or mortality in patients with acutely decompensated heart failure. The results of trials comparing intravenous loop diuretics to mechanical fluid removal by isolated venovenous ultrafiltration have yielded conflicting results. Studies evaluating early decongestive strategies have shown that ultrafiltration removed more fluid and was associated with fewer heart failure-related rehospitalization than intravenous loop diuretics. In contrast, when used in the setting of worsening renal function, ultrafiltration was associated with poorer renal outcomes and no reduction in heart failure events. The AVOID-HF trial seeks to determine if an early strategy of ultrafiltration in patients with acutely decompensated heart failure is associated with fewer heart failure events at 90 days compared with a strategy based on intravenous loop diuretics. Study subjects from 40 highly experienced institutions are randomized to either early ultrafiltration or intravenous loop diuretics. In both treatment arms, fluid removal therapies are adjusted according to the patients' hemodynamic condition and renal function. The study was unilaterally terminated by the sponsor in the absence of futility and safety concerns after the enrollment of 221 subjects, or 27% of the originally planned sample size of 810 patients. The AVOID-HF trial's principal aim is to compare the safety and efficacy of ultrafiltration vs that of intravenous loop diuretics in patients hospitalized with acutely decompensated heart failure. Because stepped treatment approaches are applied in both ultrafiltration and intravenous loop diuretics groups and the primary end point is time to first heart failure event within 90 days, it is hoped that the AVOID-HF trial, despite its untimely termination by the sponsor, will provide further insight on how to optimally decongest patients with fluid-overloaded heart failure. Copyright © 2015. Published by Elsevier Inc.

Production of egg white protein hydrolysates with improved antioxidant capacity in a continuous enzymatic membrane reactor: optimization of operating parameters by statistical design.

PubMed

Jakovetić Tanasković, Sonja; Luković, Nevena; Grbavčić, Sanja; Stefanović, Andrea; Jovanović, Jelena; Bugarski, Branko; Knežević-Jugović, Zorica

2018-01-01

This study focuses on the influence of operating conditions on Alcalase-catalyzed egg white protein hydrolysis performed in a continuously stirred tank reactor coupled with ultrafiltration module (10 kDa). The permeate flow rate did not significantly affect the degree of hydrolysis (DH), but a significant increase in process productivity was apparent above flow rate of 1.9 cm 3 min -1 . By contrast, an increase in enzyme/substrate ( E / S ) ratio provided an increase in DH, but a negative correlation was observed between E / S ratio and productivity. The relationship between operating conditions and antioxidant properties of the hydrolysates, measured by three methods, was studied using Box-Behnken experimental design and response surface methodology. The statistical analysis showed that each variable (impeller speed, E / S ratio, and permeate flow rate) had a significant effect on the antioxidant capacity of all tested systems. Nevertheless, obtained response functions revealed that antioxidative activity measured by DPPH, ABTS and FRAP methods were affected differently by the same operating conditions. High impeller speeds and low permeate flow rates favor ABTS while high impeller speeds and high permeate flow rates had a positive effect on the DPPH scavenging activity. On the other hand, the best results obtained with FRAP method were achieved under moderate operating conditions. The integration of the reaction and ultrafiltration membrane separation in a continuous manner appears to be a right approach to improve and intensify the enzymatic process, enabling the production of peptides with desired antioxidant activity.

Ultrafiltration of hemicellulose hydrolysate fermentation broth

NASA Astrophysics Data System (ADS)

Kresnowati, M. T. A. P.; Desiriani, Ria; Wenten, I. G.

2017-03-01

Hemicelulosic material is often used as the main substrate to obtain high-value products such as xylose. The five carbon sugar, xylose, could be further processed by fermentation to produce xylitol. However, not only the hemicellulose hydrolysate fermentation broth contains xylitol, but also metabolite products, residual substances, biomass and mineral salts. Therefore, in order to obtain the end products, various separation processes are required to separate and purify the desired product from the fermentation broth. One of the most promising downstream processing methods of fermentation broth clarification is ultrafiltration due to its potential for energy saving and higher purity. In addition, ultrafiltration membrane has a high performance in separating inhibitory components in the fermentation broth. This paper assesses the influence of operating conditions; including trans-membrane pressure, velocity, pH of the fermentation broth solutions, and also to the xylitol concentration in the product. The challenges of the ultrafiltration process will be pointed out.

[Dialysis and ultrafiltration therapy in patients with cardio-renal syndrome: recommendations of the working group "heart-kidney" of the German Cardiac Society and the German Society of Nephrology].

PubMed

Schwenger, V; Remppis, B A; Westenfeld, R; Weinreich, T; Brunkhorst, R; Schieren, G; Krumme, B; Haller, H; Schmieder, R; Schlieper, G; Frye, B; Hoppe, U C; Hoyer, J; Keller, T; Blumenstein, M; Schunkert, H; Mahfoud, F; Rump, L C

2014-02-01

Renal failure is common in patients with severe heart failure. This complex pathophysiological interaction has been classified as cardio-renal syndrome. In these patients hydropic decompensation is the main cause of hospitalization. In patients with refractory heart failure, characterized by diuretic resistance and congestion due to volume overload, ultrafiltration has to be considered. In acute decompensated heart failure with worsening of renal function, extracorporeal ultrafiltration is the preferred treatment modality. On the other hand, patients suffering from chronic decompensated heart failure, particularly patients with ascites, will profit from the treatment specific advantages of peritoneal ultrafiltration. Prerequisite for an optimized care of patients with cardio-renal syndrome is the close collaboration among intensive care doctors, cardiologists and nephrologists. © Georg Thieme Verlag KG Stuttgart · New York.

Physicochemical and Microbiological Properties of Yogurt-cheese Manufactured with Ultrafiltrated Cow's Milk and Soy Milk Blends

PubMed Central

Lee, Na-Kyoung; Mok, Bo Ram; Jeewanthi, Renda Kankanamge Chaturika; Yoon, Yoh Chang; Paik, Hyun-Dong

2015-01-01

The objective of this study was to develop yogurt-cheese using cow’s milk, ultrafiltrated cow’s milk, and soy milk. The addition of soy milk and ultrafiltrated milk increased the amount of protein in the yogurt-cheese. Yogurt-cheeses were made using cheese base using 10% and 20% soy milk with raw and ultrafiltrated cow’s milk, and stored at 4℃ during 2 wk. The yield of yogurt-cheeses made with added soy milk was decreased and the cutting point was delayed compared to yogurt-cheese made without soy milk. Yogurt-cheese made using ultrafiltrated cow’s milk showed the highest yield. However, yogurt-cheese made with added soy milk had higher protein content and titratable acidity than yogurt-cheese made using raw and ultrafiltrated cow’s milk. Fat and lactose contents in the yogurt-cheese made with added soy milk were lower. Yogurt-cheeses made with added soy milk contained several soy protein bands corresponding to the sizes of α2-, β-, and κ-casein band. Yogurt-cheese made with added soy milk had similar elasticity to yogurt-cheese made without soy milk but had lower cohesiveness. There was no significant difference in the number of lactic acid bacteria in the different cheeses, as all had over 8.0 Log CFU/g. Considering these data and the fact that proteins and fats of vegetable origin with high biological value were observed as well as unsaturated fats, yogurt-cheese made with added soy milk can be considered to be a functional food. PMID:26761829

Effect of Ultrafiltration on Pulmonary Function and Interleukins in Patients Undergoing Cardiopulmonary Bypass.

PubMed

Kosour, Carolina; Dragosavac, Desanka; Antunes, Nilson; Almeida de Oliveira, Rosmari Aparecida Rosa; Martins Oliveira, Pedro Paulo; Wilson Vieira, Reinaldo

2016-08-01

To evaluate the effect of ultrafiltration on interleukins, TNF-α levels, and pulmonary function in patients undergoing coronary artery bypass grafting (CABG). Prospective, randomized, controlled trial. University hospital. Forty patients undergoing CABG were randomized into a group assigned to receive ultrafiltration (UF) during cardiopulmonary bypass (CPB) or into another group (control) that underwent the same procedure but without ultrafiltration. Interleukins and TNF-α levels, pulmonary gas exchange, and ventilatory mechanics were measured in the preoperative, intraoperative, and postoperative periods. Interleukins and TNF-α also were analyzed in the perfusate of the test group. There were increases in IL-6 and IL-8 at 30 minutes after CPB and 6, 12, 24, and 36 hours after surgery, along with an increase in TNF-α at 30 minutes after CPB and 24, 36, and 48 hours after surgery in both groups. IL-1 increased at 30 minutes after CPB and 12 hours after surgery, while IL-6 increased 24 and 36 hours after surgery in the UF group. The analysis of the ultrafiltrate showed the presence of TNF-α and traces of IL-1β, IL-6, and IL-8. There were alterations in the oxygen index, alveolar-arterial oxygen difference, deadspace, pulmonary static compliance and airway resistance after anesthesia and sternotomy, as well as in airway resistance at 6 hours after surgery in both groups, with no difference between them. Ultrafiltration increased the serum level of IL-1 and IL-6, while it did not interfere with gas exchange and pulmonary mechanics in CABG. Copyright © 2016 Elsevier Inc. All rights reserved.

Use of a plant-derived enzyme template for the production of the green-note volatile hexanal.

PubMed

Schade, Frank; Thompson, John E; Legge, Raymond L

2003-11-05

Hexanal is a key organoleptic element of green-note that is found in both fragrances and flavors. We report a novel process for the production of hexanal using immobilized enzyme templates extracted from different plant sources in combination with hollow-fiber ultrafiltration for in situ separation. Enzyme templates, known to be responsible for the synthesis of hexanal from linoleic acid (18:2), were isolated from naturally enriched tissues including carnation petals, strawberry and tomato leaves. These templates were immobilized in an alginate matrix and used as a biocatalyst in a packed-bed bioreactor. Continuous product recovery was achieved using a hollow-fiber ultrafiltration unit. The effects of pH, reaction temperature, and substrate and enzyme concentrations were studied and their effects on hexanal generation identified and optimized. Utilizing optimized conditions, hexanal production 112-fold higher than endogenous steady-state levels in a corresponding amount of plant tissue could be achieved over a 30-minute period. Based on the reactor studies, product inhibition also appears to be an important factor for bioreactor-based hexanal production. Copyright 2003 Wiley Periodicals, Inc.

Evaluation of Ultrafiltration Performance for Phospholipid Separation

NASA Astrophysics Data System (ADS)

Aryanti, N.; Wardhani, D. H.; Maulana, Z. S.; Roberto, D.

2017-11-01

Ultrafiltration membrane for degumming of crude palm oil has been applied as an alternative method since the membrane process required less procedure than the conventional degumming. This research focused on the examination of ultrafiltration performance for phospholipid separation from model crude palm oil degumming. Specifically, profile flux and rejection, as well as blocking mechanism, were investigated. Feed consisting of Refined Crude Palm Oil - Isopropanol - Lecithin mixtures were represented as crude palm oil degumming. Lecithin was denoted a phospholipid component, and the concentrations of lecithin in feed were varied to 0.1%, 0.2%, and 0.3%. The concentration of phospholipid was determined as phosphor content. At the concentration of lecithin in feed representing phospholipid concentration of 8,45 mg/kg, 8,45 mg/kg, 24,87 mg/kg and 57,58 mg/kg, respectively. Flux profiles confirmed that there was a flux decline during filtration. In addition, the lecithin concentrations do not significantly effect on further flux decline. Rejection characteristic and phospholipid concentration in the permeate showed that the phospholipid rejections by ultrafiltration were in the range of 23-79,5% representing permeate’s phospholipid concentration of 1,73 - 44,25 mg/kg. Evaluation of fouling mechanism by Hermia’s blocking model confirmed that the standard blocking is the dominant mechanism in the ultrafiltration of lecithin mixture.

Purification of Drug Loaded PLGA Nanoparticles Prepared by Emulsification Solvent Evaporation Using Stirred Cell Ultrafiltration Technique.

PubMed

Paswan, Suresh K; Saini, T R

2017-12-01

The emulsifiers in an exceedingly higher level are used in the preparation of drug loaded polymeric nanoparticles prepared by emulsification solvent evaporation method. This creates great problem to the formulator due to their serious toxicities when it is to be administered by parenteral route. The final product is therefore required to be freed from the used surfactants by the conventional purification techniques which is a cumbersome job. The solvent resistant stirred cell ultrafiltration unit (Millipore) was used in this study using polyethersulfone ultrafiltration membrane (Biomax®) having pore size of NMWL 300 KDa as the membrane filter. The purification efficiency of this technique was compared with the conventional centrifugation technique. The flow rate of ultrafiltration was optimized for removal of surfactant (polyvinyl alcohol) impurities to the acceptable levels in 1-3.5 h from the nanoparticle dispersion of tamoxifen prepared by emulsification solvent evaporation method. The present investigations demonstrate the application of solvent resistant stirred cell ultrafiltration technique for removal of toxic impurities of surfactant (PVA) from the polymeric drug nanoparticles (tamoxifen) prepared by emulsification solvent evaporation method. This technique offers added benefit of producing more concentrated nanoparticles dispersion without causing significant particle size growth which is observed in other purification techniques, e.g., centrifugation and ultracentrifugation.

Water hammer reduces fouling during natural water ultrafiltration.

PubMed

Broens, F; Menne, D; Pothof, I; Blankert, B; Roesink, H D W; Futselaar, H; Lammertink, R G H; Wessling, M

2012-03-15

Today's ultrafiltration processes use permeate flow reversal to remove fouling deposits on the feed side of ultrafiltration membranes. We report an as effective method: the opening and rapid closing of a valve on the permeate side of an ultrafiltration module. The sudden valve closure generates pressure fluctuations due to fluid inertia and is commonly known as "water hammer". Surface water was filtrated in hollow fiber ultrafiltration membranes with a small (5%) crossflow. Filtration experiments above sustainable flux levels (>125 l (m2h)(-1)) show that a periodic closure of a valve on the permeate side improves filtration performance as a consequence of reduced fouling. It was shown that this effect depends on flux and actuation frequency of the valve. The time period that the valve was closed proved to have no effect on filtration performance. The pressure fluctuations generated by the sudden stop in fluid motion due to the valve closure are responsible for the effect of fouling reduction. High frequency recording of the dynamic pressure evolution shows water hammer related pressure fluctuations to occur in the order of 0.1 bar. The pressure fluctuations were higher at higher fluxes (higher velocities) which is in agreement with the theory. They were also more effective at higher fluxes with respect to fouling mitigation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Dissolution behaviour of 238U, 234U and 230Th deposited on filters from personal dosemeters.

PubMed

Becková, Vera; Malátová, Irena

2008-01-01

Kinetics of dissolution of (238)U, (234)U and (230)Th dust deposited on filters from personal alpha dosemeters was studied by means of a 26-d in vitro dissolution test with a serum ultrafiltrate simulant. Dosemeters had been used by miners at the uranium mine 'Dolní Rozínka' at Rozná, Czech Republic. The sampling flow-rate as declared by the producer is 4 l h(-1) and the sampling period is typically 1 month. Studied filters contained 125 +/- 6 mBq (238)U in equilibrium with (234)U and (230)Th; no (232)Th series nuclides were found. Half-time of rapid dissolution of 1.4 d for (238)U and (234)U and slow dissolution half-times of 173 and 116 d were found for (238)U and (234)U, respectively. No detectable dissolution of (230)Th was found.

Ultrafiltrate and microdialysis DL probe in vitro recoveries: electrolytes and metabolites

NASA Technical Reports Server (NTRS)

Janle, E. M.; Cregor, M.

1996-01-01

UF ultrafiltration and DL microdialysis probes are well-suited for sampling interstitial concentrations of ions and metabolites in peripheral tissue. The first step in utilization of membrane sampling techniques is to determine the recovery characteristics of the probes in vitro.

Tangential Ultrafiltration of Aqueous "Saccharomyces Cerevisiae" Suspensions

ERIC Educational Resources Information Center

Silva, Carlos M.; Neves, Patricia S.; Da Silva, Francisco A.; Xavier, Ana M. R. B.; Eusebio, M. F. J.

2008-01-01

Experimental work on ultrafiltration is presented to illustrate the practical and theoretical principles of this separation technique. The laboratory exercise comprises experiments with pure water and with aqueous "Saccharomyces cerevisiae" (from commercial Baker's yeast) suspensions. With this work students detect the characteristic phenomena…

Production of Hypoallergenic Antibacterial Peptides from Defatted Soybean Meal in Membrane Bioreactor: A Bioprocess Engineering Study with Comprehensive Product Characterization

PubMed Central

2017-01-01

Summary Hypoallergenic antibacterial low-molecular-mass peptides were produced from defatted soybean meal in a membrane bioreactor. In the first step, soybean meal proteins were digested with trypsin in the bioreactor, operated in batch mode. For the tryptic digestion of soybean meal protein, optimum initial soybean meal concentration of 75 g/L, temperature of 40 °C and pH=9.0 were determined. After enzymatic digestion, low-molecular-mass peptides were purified with cross-flow flat sheet membrane (pore size 100 µm) and then with tubular ceramic ultrafiltration membrane (molecular mass cut-off 5 kDa). Effects of transmembrane pressure and the use of a static turbulence promoter to reduce the concentration polarization near the ultrafiltration membrane surface were examined and their positive effects were proven. For the filtration with ultrafiltration membrane, transmembrane pressure of 3·105 Pa with 3-stage discontinuous diafiltration was found optimal. The molecular mass distribution of purified peptides using ultrafiltration membrane was determined by a liquid chromatography–electrospray ionization quadrupole time-of-flight mass spectrometry setup. More than 96% of the peptides (calculated as relative frequency) from the ultrafiltration membrane permeate had the molecular mass M≤1.7 kDa and the highest molecular mass was found to be 3.1 kDa. The decrease of allergenic property due to the tryptic digestion and membrane filtration was determined by an enzyme-linked immunosorbent assay and it was found to exceed 99.9%. It was also found that the peptides purified in the ultrafiltration membrane promoted the growth of Pediococcus acidilactici HA6111-2 and they possessed antibacterial activity against Bacillus cereus. PMID:29089846

Microfiltration and Ultrafiltration Membranes for Drinking Water

EPA Science Inventory

This article provides a concise and abbreviated summary of AWWA Manual of Practice M53, Microfiltration and Ultrafiltration Membranes for Drinking Water, to serve as a quick point of reference. For convenience, the article’s organization matches that of M53, as follows: • wate...

Class and Home Problems. The Lambert W Function in Ultrafiltration and Diafiltration

ERIC Educational Resources Information Center

Foley, Greg

2016-01-01

Novel analytical solutions based on the Lambert W function for two problems in ultrafiltration and diafiltration are described. Example problems, suitable for incorporation into an introductory module in unit operations, membrane processing, or numerical methods are provided in each case.

Microanatomy and ultrastructure of the excretory system of two pelagic opisthobranch species (Gastropoda: Gymnosomata and Thecosomata).

PubMed

Fahrner, A; Haszprunar, G

2000-04-01

The microanatomy and ultrastructure of the excretory system of Pneumoderma sp. (Gymnosomata) and Creseis virgula Rang, 1828 (Thecosomata) have been investigated by means of semithin serial sections, reconstructions and transmission electron microscopy. The studies revealed a functional metanephridial system consisting of a heart with a single ventricle and auricle in a pericardial cavity and a single kidney in both species. Podocytes in the atrial wall of the pericardial epithelium are the site of ultrafiltration, whereas the flat epithelium of the kidney with numerous basal infoldings and a dense microvillous border on the luminal surface suggests modification of the ultrafiltrate. In Pneumoderma sp., additional loci of ultrafiltration with identical fine structure (meandering slits with diaphragms covered by extracellular matrix) occur in the solitary rhogocytes (pore cells). The presence of podocytes situated on the atrial wall in representatives of two higher opisthobranch taxa contradicts former ideas on the loss of the primary site of ultrafiltration in the ancestors of the Opisthobranchia.

Separation of water-soluble polysaccharides from Cyclocarya paliurus by ultrafiltration process.

PubMed

Xie, Jian-Hua; Shen, Ming-Yue; Nie, Shao-Ping; Zhao, Qiang; Li, Chang; Xie, Ming-Yong

2014-01-30

In this study, ultrafiltration membrane process was employed to separate polysaccharides from Cyclocarya paliurus (Batal.) Iljinskaja (C. paliurus) to simulate industrial production. Meanwhile, the molecular weight distribution of C. paliurus polysaccharides was investigated by gel permeation chromatography. Four fractions were obtained and named as CPPS-A, CPPS-B, CPPS-C and CPPS-D, respectively. CPPS-A and CPPS-B contained approximately 69.5% and 12.7% of polysaccharides, whose molecular weight were in the range of 100-300 kDa and 120 kDa, respectively. CPPS-C was comprised of two polysaccharides with average molecular weight of 40 kDa and 15 kDa. Results showed that ultrafiltration resulted in the removal of parts of small molecule weight polysaccharides, the increase of proportion of high molecule weight ones and the obvious improvement of quality of products. Compared with ethanol precipitation and gel permeation chromatography techniques, ultrafiltration showed many advantages, and also provided theoretical support for industrial manufacturing of C. paliurus polysaccharides in separation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cost savings from peritoneal dialysis therapy time extension using icodextrin.

PubMed

Johnson, David W; Vincent, Kaia; Blizzard, Sophie; Rumpsfeld, Markus; Just, Paul

2003-01-01

Previous retrospective studies have reported that icodextrin may prolong peritoneal dialysis (PD) treatment time in patients with refractory fluid overload (RFO). Because the annual cost of PD therapy is lower than that of hemodialysis (HD) therapy in Australia, we prospectively investigated the ability of icodextrin to prolong PD technique survival in patients with RFO. We used a computer model to estimate the savings associated with that therapeutic strategy, based on annual therapy costs determined in a regional PD and HD costing exercise. Patients who met standard criteria for RFO and who were otherwise to be converted immediately to HD, were asked to consent to an open-label assessment of the ability of icodextrin to delay the need to start HD. Time to conversion to HD was measured. The study enrolled 39 patients who were followed for a mean period of 1.1 years. Icodextrin significantly increased peritoneal ultrafiltration by a median value of 368 mL daily. It prolonged technique survival by a mean period of 1.21 years [95% confidence interval (CI): 0.80-1.62 years]. Extension of PD treatment time by icodextrin was particularly marked for patients who had ultrafiltration failure (UFF, n = 20), defined as net daily peritoneal ultrafiltration < 1 L daily (mean extension time: 1.70 years; 95% CI: 1.16-2.25 years). Overall, annualized savings were US$3,683 per patient per year. If just the patients with UFF were considered, the savings increased to US$4,893 per year. Icodextrin prolongs PD technique survival in patients with RFO, permitting them to continue on their preferred therapy. In Australia, that practice is highly cost-effective, particularly in individuals with UFF.

Study to determine the technical and economic feasibility of reclaiming chemicals used in micellar polymer and low tension surfactant flooding. Final report. [Ultrafiltration membranes and reverse osmosis membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stephens, R.H.; Himmelblau, A.; Donnelly, R.G.

1978-02-01

Energy Resources Company has developed a technology for use with enhanced oil recovery to achieve emulsion breaking and surfactant recovery. By using ultrafiltration membranes, the Energy Resources Company process can dewater an oil-in-water type emulsion expected from enhanced oil recovery projects to the point where the emulsion can be inverted and treated using conventional emulsion-treating equipment. By using a tight ultrafiltration membrane or a reverse osmosis membrane, the Energy Resources Company process is capable of recovering chemicals such as surfactants used in micellar polymer flooding.

Treatment of silica effluents: ultrafiltration or coagulation-decantation.

PubMed

Ndiaye, P I; Moulin, P; Dominguez, L; Millet, J C; Charbit, F

2004-12-10

In the electronics industry, the preparation of silicon plates generates effluents that contain a great amount of colloidal silica. Two processes--decantation and ultrafiltration--are studied with in view the treatment of the effluents released by the firm Rockwood Electronic Materials. The feasibility of each of the two processes is studied separately and their operating parameters optimized. Both processes allow the recovery of a great proportion of the initial effluent (over 89%) as transparent and colorless water that can be reused at the start of a line. In view of the results and of the compared advantages and disadvantages of the two processes, ultrafiltration will be selected for the industrial unit.

Pilot-scale investigation on the removal of organic foulants in secondary effluent by slow sand filtration prior to ultrafiltration.

PubMed

Zheng, Xing; Ernst, Mathias; Jekel, Martin

2010-05-01

Natural biofiltration processes have been verified as effective pre-treatment choice improving the performance of low-pressure membranes (MF/UF) in wastewater reclamation. In the present work, pilot-scale slow sand filtration (SSF) was used to simulate bank filtration at high filtration rates (from 0.25m/h to 0.5m/h) to filter secondary effluent prior to UF. The results showed that SSF improved the performance of UF to a large extent. Related to previous work biopolymers are considered as major dissolved organic foulants in treated wastewater. The removal of these organic foulants in slow sand filters and factors affecting the performance of SSF were investigated. It was observed that the removal of biopolymers took place mainly at the upper sand layer and was related to biological degradation. Tests on the degradability of biopolymers verified that they are biodegradable. Sixteen months monitoring of biopolymer concentration in the secondary effluent indicated that it varied seasonally. In winter season the concentration was much higher than during the summer months. Higher temperature and lower biopolymer concentration led to more effective foulants removal and more sustainable operation of SSF. During the whole experimental period, the performance of SSF was always better at filtration rate of 0.25m/h than at 0.5m/h. Under the present experimental conditions, SSF exhibited stable and effective biopolymer removal at temperatures higher than 15 degrees C, at biopolymer concentrations lower than 0.5mg C/L and with sufficient oxygen available.

[Ultrafiltration versus intravenous diuretics in decompensated heart failure: a meta-analysis of randomized controlled trials].

PubMed

Zhao, Yu-liang; Zhang, Ling; Yang, Ying-ying; Tang, Yi; Liu, Fang; Fu, Ping

2013-08-13

To explore whether ultrafiltration is superior to intravenous diuretics in ameliorating fluid overload and preserving renal functions in decompensated heart failure patients. By searching in Pubmed, Cochrane Library, Embase, Springer, WanFang, CQVIP, CNKI and CBM database as well as related Chinese journals, qualified randomized controlled trials (RCTs) were included for meta-analysis by Revman 5.0 and STATA 10.0. Six RCTs were included with 241 patients in ultrafiltration group and 240 patients in intravenous diuretics group. Pooled analyses demonstrated ultrafiltration was superior to intravenous diuretics in the aspects of weight loss (WMD = 1.44 kg, 95%CI:0.33-2.55 kg, P = 0.01) and fluid removal (WMD = 1.23 kg, 95%CI:0.63-1.82 kg, P < 0.01) while no significant difference was observed in serum creatinine level (WMD = -5.70 µmol/L, 95%CI: -35.02-23.61 µmol/L, P = 0.70), serum creatinine change from baseline (WMD = 4.74 µmol/L, 95%CI:-13.72-23.20 µmol/L, P = 0.61), mortality (RR = 1.09, 95%CI: 0.69-1.70, P = 0.72) or rehospitalization (RR = 0.92, 95%CI:0.53-1.61, P = 0.78). For decompensated heart failure patients, ultrafiltration is superior to intravenous diuretics in mitigating fluid overload. No intergroup difference was observed in renal function preservation, mortality or rehospitalization.

Removal of copper ions from aqueous solutions by means of micellar-enhanced ultrafiltration

NASA Astrophysics Data System (ADS)

Kowalska, Izabela; Klimonda, Aleksandra

2017-11-01

The aim of the study was to assess the usefulness of micellar-enhanced ultrafiltration (MEUF) for removal of copper ions from water solutions in comparison with classic ultrafiltration process. The tests were conducted in a semi-pilot membrane installation with the use of ultrafiltration module KOCH/ROMICON® at a transmembrane pressure of 0.05 MPa. The effect of concentration of copper ions on ultrafiltration process efficiency was investigated. The second part of the tests concerned the removal of copper ions by MEUF under wide range of anionic surfactant concentration (0.25, 1, and 5 CMC (critical micelle concentration)). Concentration of copper ions in model solutions was equal to 5, 20, and 50 mg Cu/L. Furthermore, the effect of surfactant leakage to the permeate side during filtration was evaluated. Conducted experiments confirmed effectiveness of MEUF in copper ions removal. For the highest copper concentration in the feed (i.e. 50 mg/L), the average concentration of copper ions in the permeate ranged from 1.2-4.7 mg Cu/L depending on surfactant concentration. During filtration experiments, UF module exhibited stable transport properties for model solutions containing copper. For the highest concentration of metal, the decrease of permeate flux did not exceed 11% after 60 minutes of filtration. In the presence of the surfactant, a slight deterioration of transport properties was observed.

Ceramic membrane fouling during ultrafiltration of oil/water emulsions: roles played by stabilization surfactants of oil droplets.

PubMed

Lu, Dongwei; Zhang, Tao; Ma, Jun

2015-04-07

Oil/water (O/W) emulsion stabilized by surfactants is the part of oily wastewater that is most difficult to handle. Ceramic membrane ultrafiltration presently is an ideal process to treat O/W emulsions. However, little is known about the fouling mechanism of the ceramic membrane during O/W emulsion treatment. This paper investigated how stabilization surfactants of O/W emulsions influence the irreversible fouling of ceramic membranes during ultrafiltration. An unexpected phenomenon observed was that irreversible fouling was much less when the charge of the stabilization surfactant of O/W emulsions is opposite to the membrane. The less ceramic membrane fouling in this case was proposed to be due to a synergetic steric effect and demulsification effect which prevented the penetration of oil droplets into membrane pores and led to less pore blockage. This proposed mechanism was supported by cross section images of fouled and virgin ceramic membranes taken with scanning electron microscopy, regression results of classical fouling models, and analysis of organic components rejected by the membrane. Furthermore, this mechanism was also verified by the existence of a steric effect and demulsification effect. Our finding suggests that ceramic membrane oppositely charged to the stabilization surfactant should be applied in ultrafiltration of O/W emulsions to alleviate irreversible membrane fouling. It could be a useful rule for ceramic membrane ultrafiltration of oily wastewater.

Flexographic newspaper deinking : treatment of wash filtrate effluent by membrane technology

Treesearch

B. Chabot; G.A. Krishnagopalan; S. Abubakr

1999-01-01

Ultrafiltration was investigated as a means to remove flexographic ink pigments from wash filtrate effluent generated from various mixtures of flexographic and offset old newspapers from deinking operations. Membrane separation efficiency was assessed from permeate flux, fouling rate, and ease of membrane regeneration (cleaning). Ultrafiltration was capable of...

NCL-01: Nanomedicine Drug Release Study in Human Plasma Using Stable Isotope Tracer Ultrafiltration Assay (SITUA)  | Frederick National Laboratory for Cancer Research

Cancer.gov

The Nanotechnology Characterization Laboratory will evaluate drug release from a nanoparticulate formulation in vitro in human plasma, using a novel stable isotope tracer ultrafiltration assay (SITUA) developed at the laboratory. The SITUA is a metho

EFFICIENT RECOVERY OF ENTEROCOCCI FROM MARINE AND FRESH WATER BEACHES BY A 30,000 MOLECULAR WEIGHT CUTOFF HOLLOW FIBER ULTRAFILTER

EPA Science Inventory

Ultrafiltration systems have been used to concentrate pathogens from various types of fresh water samples. However, less work has been done with marine waters for the concentration of pathogens or indicator bacteria. An ultrafiltration approach to concentrate indicator bacteria...

Coagulation pretreatment for ultrafiltration of deinking effluents containing flexographic inks

Treesearch

Bruno Chabot; Gopal A. Krishnagopalan; Said Abubakr

1999-01-01

This study was carried out to determine the potential of coagulation pretreatment with organic or inorganic coagulants to improve ultrafiltration performance during processing of wash deinking effluents containing flexographic inks. Wash filtrate effluents generated from mixtures of old flexographic and offset newspapers and old magazines were pretreated with a...

Evaluation of Hollow-Fiber Ultrafiltration Primary Concentration of Pathogens and Secondary Concentration of Viruses from Water

EPA Science Inventory

In this study, tangential hollow-fiber ultrafiltration (HFUF) was evaluated for virus and Cryptosporidium parvum concentration. Recovery of viruses at a low filtration rate was found to be significantly greater than at a higher filtration rate, with the recoveries of bacteriopha...

A Modified EPA Method 1623 that Uses Tangential Flow Hollow-Fiber Ultrafiltration and Heat Dissociation Steps to Detect Waterborne Cryptosporidum and Giardia spp.

EPA Science Inventory

This protocol describes the use of a tangential flow hollow-fiber ultrafiltration sample concentration system and a heat dissociation as alternative steps for the detection of waterborne Cryptosporidium and Giardia species using EPA Method 1623.

INVESTIGATION OF CONVENTIONAL MEMBRANE AND TANGENTIAL FLOW ULTRAFILTRATION ARTIFACTS AND THEIR APPLICATION TO THE CHARACTERIZATION OF FRESHWATER COLLOIDS

EPA Science Inventory

Artifacts associated with the fractionation of colloids in a freshwater sample were investigated for conventional membrane filtration (0.45 micron cutoff), and two tangential flow ultrafiltration cartridges (0.1 micron cutoff and 3000 MW cutoff). Membrane clogging during conventi...

Role of electrostatic interactions during protein ultrafiltration.

PubMed

Rohani, Mahsa M; Zydney, Andrew L

2010-10-15

A number of studies over the last decade have clearly demonstrated the importance of electrostatic interactions on the transport of charged proteins through semipermeable ultrafiltration membranes. This paper provides a review of recent developments in this field with a focus on the role of both protein and membrane charge on the rate of protein transport. Experimental results are analyzed using available theoretical models developed from the solution of the Poisson-Boltzmann equation for the partitioning of a charged particle into a charged pore. The potential of exploiting these electrostatic interactions for selective protein separations and for the development of ultrafiltration membranes with enhanced performance characteristics is also examined. Copyright © 2010 Elsevier B.V. All rights reserved.

REMOVAL OF MICROBIAL CONTAMINANTS IN DRINKING WATER: KOCH MEMBRANE SYSTEMS, HF-82-35-PMPW™ ULTRAFILTRATION MEMBRANE

EPA Science Inventory

Two Koch Membrane Systems HF-82-35-PMPW ultrafiltration membrane cartridges were tested for removal of viruses, bacteria, and protozoan cysts at NSF’s Drinking Water Treatment Systems Laboratory. The ETV testing was conducted as part of a series of evaluations of the Expeditiona...

Structure and Activity of a New Low Molecular Weight Heparin Produced by Enzymatic Ultrafiltration

PubMed Central

FU, LI; ZHANG, FUMING; LI, GUOYUN; ONISHI, AKIHIRO; BHASKAR, UJJWAL; SUN, PEILONG; LINHARDT, ROBERT J.

2014-01-01

The standard process for preparing the low molecular weight heparin (LMWH) tinzaparin, through the partial enzymatic depolymerization of heparin, results in a reduced yield due to the formation of a high content of undesired disaccharides and tetrasaccharides. An enzymatic ultrafiltration reactor for LMWH preparation was developed to overcome this problem. The behavior, of the heparin oligosaccharides and polysaccharides using various membranes and conditions, was investigated to optimize this reactor. A novel product, LMWH-II, was produced from the controlled depolymerization of heparin using heparin lyase II in this optimized ultrafiltration reactor. Enzymatic ultrafiltration provides easy control and high yields (>80%) of LMWH-II. The molecular weight properties of LMWH-II were similar to other commercial LMWHs. The structure of LMWH-II closely matched heparin’s core structural features. Most of the common process artifacts, present in many commercial LWMHs, were eliminated as demonstrated by 1D and 2D nuclear magnetic resonance spectroscopy. The antithrombin III and platelet factor-4 binding affinity of LMWH-II were comparable to commercial LMWHs, as was its in vitro anticoagulant activity. PMID:24634007

Application of ultrafiltration in the pulp and paper industry: metals removal and whitewater reuse.

PubMed

Oliveira, C R; Silva, C M; Milanez, A F

2007-01-01

In the pulp and paper industry, the water use minimization is a constant target. One way to reduce water use is to recycle the effluent in a closed-cycle concept. In paper mills, the main source of liquid effluent is the so-called whitewater, which is the excess water, originated from pulp stock dewatering and other fibre contaminated water. This research studied the reuse of paper mill whitewater after membrane ultrafiltration (UF) in the paper machine and in the pulp bleach plant of an integrated mill. Contaminant removal and flux behaviour of the UF system were evaluated. The treatment by ultrafiltration was technically feasible and the treated whitewater had good potential to be reused in some processes in the paper machine. The reuse of ultrafiltered whitewater in the bleaching plant was not recommended because of the high level of soluble calcium present in this stream. Therefore, a combined treatment of the whitewater using the principle of precipitation and ultrafiltration was proposed showing good results and enabling the use of the treated whitewater in the bleach plant.

Preparation of ultrafiltration membrane by phase separation coupled with microwave irradiation

NASA Astrophysics Data System (ADS)

Suryani, Puput Eka; Purnama, Herry; Susanto, Heru

2015-12-01

Preparation of low fouling ultrafiltration membrane is still a big challenge in the membrane field. In this paper, polyether sulfone (PES) ultrafiltration membranes were prepared by non-solvent-induced phase separation (NIPS) coupled with microwave irradiation. Polyethylene glycol (PEG) and polyethylene glycol methacrylate (PEGMA) were used as additives to improve membrane hydrophilicity. In this study, the concentration of additive, irradiation time and microwave power was varied. The membranes were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy, while the performances were tested by adsorptive and ultrafiltration fouling experiments. The results show that the irradiation time and irradiation power are very important parameter that influence the membrane characteristic. In addition, type and concentration of additive are other important parameters. The results suggest that microwave irradiation is the most important parameter influencing the membrane characteristic. Both pure water flux and fouling resistance increase with increasing irradiation time, power irradiation, and additive concentration. PES membrane with addition of 10% w/w PEG and irradiated by 130 W microwave power for 180 seconds is the best membrane performance.

Research on the experiment of reservoir water treatment applying ultrafiltration membrane technology of different processes.

PubMed

Zhang, Liyong; Zhang, Penghui; Wang, Meng; Yang, Kai; Liu, Junliang

2016-09-01

The processes and effects of coagulation-ultrafiltration (C-UF) and coagulation sedimentation-ultrafiltration (CS-UF) process used in the treatment of Dalangdian Reservoir water were compared. The experiment data indicated that 99% of turbidity removal and basically 100% of microorganism and algae removal were achieved in both C-UF and CS-UF process. The organic removal effect of CS-UF? process was slightly better than C-UF process. However, the organic removal effect under different processes was not obvious due to limitation of ultrafiltration membrane aperture. Polyaluminium chloride was taken as a coagulant in water plant. The aluminum ion removal result revealed that coagulant dosage was effectively saved by using membrane technology during megathermal high algae laden period. Within the range of certain reagent concentration and soaking time, air-water backwashing of every filtration cycle of membrane was conducted to effectively reduce membrane pollution. Besides, maintenance cleaning was conducted every 60 min. whether or not restorative cleaning was conducted depends on the pollution extent. After cleaning, recovery of membrane filtration effect was obvious.

Venoarterial modified ultrafiltration versus conventional arteriovenous modified ultrafiltration during cardiopulmonary bypass surgery.

PubMed

Mohanlall, Rakesh; Adam, Jamila; Nemlander, Arto

2014-01-01

Different types of modified ultrafiltration (MUF) systems evaluated showed that none of the MUF techniques adhered to the normal venous to arterial blood flow dynamics. This study compared a conventional arteriovenous modified ultrafiltration (AVMUF) system to a custom- designed venoarterial modified ultrafiltration (VAMUF) system. Randomized, controlled clinical study conducted at the Northwest Armed Forces Military hospital in Tabuk, Saudi Arabia. Sixty patients who underwent MUF during the years 2007 and 2009 were divided into 2 groups: the AVMUF (n=30) and the VAMUF (n=30) groups. MUF was performed for a mean time of 12 minutes in both groups. In AVMUF, blood was removed from the aorta, hemoconcentrated, and infused into the right atrium (RA). In VAMUF, blood flow was from the RA through a hemoconcentrator and re-infused into the aorta. Results of the study showed that the VAMUF group required a shorter ventilation time (P < .001), in.tensive care unit (ICU) (P=.003), and hospital stay (P=.007) than the AVMUF group. Results also demonstrated a lower percentage of fluid balance (P=.008) in the VAMUF group. The systolic (P < .001) and mean blood pres.sures (P < .001) were significantly higher after VAMUF, with a decrease in heart rate (P < .001) and central venous pressure (P=.002). The VAMUF group showed a significantly greater decrease of creatinine (P < .001), serum lactacte (P < .001), and uric acid (P < .027) over time with no significant differences in oximetry. Results prove that VAMUF is a more physiological technique than AVMUF.

Removal of Viruses in Drinking Water- Ultrafiltration Module with a Cut Fiber, Dow Chemical Company - Dow Water & Process Solutions, SFD-2880 - Ultrafiltration Module

EPA Science Inventory

The purpose of this verification was a cut fiber challenge study for the Dow Chemical Company SFD-2880 UF membrane module. MS2 coliphage virus was the surrogate challenge organism. The challenge tests followed the requirements of the Department of Health Victoria (Australia) Dr...

Hydrophobic asymmetric ultrafiltration PVDF membranes: an alternative separator for VFB with excellent stability.

PubMed

Wei, Wenping; Zhang, Huamin; Li, Xianfeng; Zhang, Hongzhang; Li, Yun; Vankelecom, Ivo

2013-02-14

Polyvinylidene fluoride (PVDF) ultrafiltration membranes were investigated for the first time in vanadium redox flow battery (VFB) applications. Surprisingly, PVDF ultrafiltration membranes with hydrophobic pore walls and relatively large pore sizes of several tens of nanometers proved able to separate vanadium ions and protons efficiently, thus being suitable as a VFB separator. The ion selectivity of this new type of VFB membrane could be tuned readily by controlling the membrane morphology via changes in the composition of the membrane casting solution, and the casting thickness. The results showed that the PVDF membranes offered good performances and excellent stability in VFB applications, where it could, performance-wise, truly substitute Nafion in VFB applications, but at a much lower cost.

Determination of total and unbound concentrations of lopinavir in plasma using liquid chromatography-tandem mass spectrometry and ultrafiltration methods.

PubMed

Illamola, S M; Labat, L; Benaboud, S; Tubiana, R; Warszawski, J; Tréluyer, J M; Hirt, D

2014-08-15

Lopinavir is an HIV protease inhibitor with high protein binding (98-99%) in human plasma. This study was designed to develop an ultrafiltration method to measure the unbound concentrations of lopinavir overcoming the non-specific binding issue. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of total concentrations of lopinavir in plasma was developed and validated, and an adaptation was also optimized and validated for the determination of unbound concentrations. The chromatographic separation was performed with a C18 column (100 mm × 2.1mm i.d., 5 μm particle size) using a mobile phase containing deionized water with formic acid, and acetonitrile, with gradient elution at a flow-rate of 350 μL min(-1). Identification of the compounds was performed by multiple reaction monitoring, using electrospray ionization in positive ion mode. The method was validated over a clinical range of 0.01-1 μg/mL for human plasma ultrafiltrate and 0.1-15 μg/mL in human plasma. The inter and intra-assay accuracies and precisions were between 0.23% and 11.37% for total lopinavir concentrations, and between 3.50% and 13.30% for plasma ultrafiltrate (unbound concentration). The ultrafiltration method described allows an accurate separation of the unbound fraction of lopinavir, circumscribing the loss of drug by nonspecific binding (NSB), and the validated LC-MS/MS methodology proposed is suitable for the determination of total and unbound concentrations of lopinavir in clinical practice. Copyright © 2014 Elsevier B.V. All rights reserved.

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT - PHYSICAL REMOVAL OF PARTICULATE CONTAMINANTS IN DRINKING WATER: POLYMEM UF 120 S2 ULTRAFILTRATION MEMBRANE MODULE, LUXENBURG, WISCONSIN

EPA Science Inventory

Verification testing of the Polymem UF120 S2 Ultrafiltration Membrane Module was conducted over a 46-day period at the Green Bay Water Utility Filtration Plant, Luxemburg, Wisconsin. The ETV testing described herein was funded in conjunction with a 12-month membrane pilot study f...

Nutrient Recovery from the Dry Grind Process Using Sequential Micro and Ultrafiltration of Thin Stillage

USDA-ARS?s Scientific Manuscript database

The effectiveness of microfiltration (MF) and ultrafiltration (UF) for nutrient recovery from a thin stillage stream was determined. When a stainless steel MF membrane (0.1 um pore size) was used, the content of solids increased from 7.0% to 22.8% with a mean permeate flux rate of 45 L/m**2/h (LMH)...

Structure and activity of a new low-molecular-weight heparin produced by enzymatic ultrafiltration.

PubMed

Fu, Li; Zhang, Fuming; Li, Guoyun; Onishi, Akihiro; Bhaskar, Ujjwal; Sun, Peilong; Linhardt, Robert J

2014-05-01

The standard process for preparing the low-molecular-weight heparin (LMWH) tinzaparin, through the partial enzymatic depolymerization of heparin, results in a reduced yield because of the formation of a high content of undesired disaccharides and tetrasaccharides. An enzymatic ultrafiltration reactor for LMWH preparation was developed to overcome this problem. The behavior, of the heparin oligosaccharides and polysaccharides using various membranes and conditions, was investigated to optimize this reactor. A novel product, LMWH-II, was produced from the controlled depolymerization of heparin using heparin lyase II in this optimized ultrafiltration reactor. Enzymatic ultrafiltration provides easy control and high yields (>80%) of LMWH-II. The molecular weight properties of LMWH-II were similar to other commercial LMWHs. The structure of LMWH-II closely matched heparin's core structural features. Most of the common process artifacts, present in many commercial LWMHs, were eliminated as demonstrated by 1D and 2D nuclear magnetic resonance spectroscopy. The antithrombin III and platelet factor-4 binding affinity of LMWH-II were comparable to commercial LMWHs, as was its in vitro anticoagulant activity. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Effect of electrostatic interactions on the ultrafiltration behavior of charged bacterial capsular polysaccharides.

PubMed

Hadidi, Mahsa; Buckley, John J; Zydney, Andrew L

2016-11-01

Charged polysaccharides are used in the food industry, as cosmetics, and as vaccines. The viscosity, thermodynamics, and hydrodynamic properties of these charged polysaccharides are known to be strongly dependent on the solution ionic strength because of both inter- and intramolecular electrostatic interactions. The goal of this work was to quantitatively describe the effect of these electrostatic interactions on the ultrafiltration behavior of several charged capsular polysaccharides obtained from Streptococcus pneumoniae and used in the production of Pneumococcus vaccines. Ultrafiltration data were obtained using various Biomax™ polyethersulfone membranes with different nominal molecular weight cutoffs. Polysaccharide transmission decreased with decreasing ionic strength primarily because of the expansion of the charged polysaccharide associated with intramolecular electrostatic repulsion. Data were in good agreement with a simple theoretical model based on solute partitioning in porous membranes, with the effective size of the different polysaccharide serotypes evaluated using size exclusion chromatography at the same ionic conditions. These results provide fundamental insights and practical guidelines for exploiting the effects of electrostatic interactions during the ultrafiltration of charged polysaccharides. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1531-1538, 2016. © 2016 American Institute of Chemical Engineers.

Impact of ozonation, anion exchange resin and UV/H2O2 pre-treatments to control fouling of ultrafiltration membrane for drinking water treatment.

PubMed

Pramanik, Biplob Kumar; Pramanik, Sagor Kumar; Sarker, Dipok Chandra; Suja, Fatihah

2017-06-01

The effects of ozonation, anion exchange resin (AER) and UV/H 2 O 2 were investigated as a pre-treatment to control organic fouling (OF) of ultrafiltration membrane in the treatment of drinking water. It was found that high molecular weight (MW) organics such as protein and polysaccharide substances were majorly responsible for reversible fouling which contributed to 90% of total fouling. The decline rate increased with successive filtration cycles due to deposition of protein content over time. All pre-treatment could reduce the foulants of a Ultrafiltration membrane which contributed to the improvement in flux, and there was a greater improvement of flux by UV/H 2 O 2 (61%) than ozonation (43%) which in turn was greater than AER (23%) treatment. This was likely due to the effective removal/breakdown of high MW organic content. AER gave greater removal of biofouling potential components (such as biodegradable dissolved organic carbon and assimilable organic carbon contents) compared to UV/H 2 O 2 and ozonation treatment. Overall, this study demonstrated the potential of pre-treatments for reducing OF of ultrafiltration for the treatment of drinking water.

[Study on the interface of human hepatocyte/micropore polypropylene ultrafiltration membrane].

PubMed

Peng, Cheng-Hong; Han, Bao-San; Gao, Chang-You; Ma, Zu-Wei; Zhao, Zhi-Ming; Wang, Yong; Liu, Hong; Zhang, Gui-di; Yang, Mei-Juan

2004-09-02

To found a new interface of human hepatocyte/micropore polypropylene ultrafiltration membrane (MPP) with good cytocompatibility so as to construct bioartificial bioreactor with polypropylene hollow fibers in future. MPP ultrafiltration membrane underwent chemical grafting modification through ultraviolet irradiation and Fe(2+) reduction. The contact angles of MPP and the modified MPP membranes were measured. Human hepatic cells L-02 were cultured. MPP and modified MPP membranes were spread on the wells of culture plate and human hepatic cells and cytodex 3 were inoculated on them. Different kinds of microscopy were used to observe the morphology of these cells. The water contact angle of MPP and the modified MPP membranes decreased from 78 degrees +/- 5 degrees to 27 degrees +/- 4 degrees (P < 0.05), which indicated that the hydrophilicity of the membrane was improved obviously after the grafting modification. Human hepatocyte L-02 did not adhere to and spread on the modified MPP membrane surface, and only grew on the microcarrier cytodex 3 with higher density and higher proliferation ratio measured by MTT. Grafting modification of acrylamide on MPP membrane is a good method to improve the human hepatocyte cytocompatibility with MPP ultrafiltration membrane.

Thermoase-Derived Flaxseed Protein Hydrolysates and Membrane Ultrafiltration Peptide Fractions Have Systolic Blood Pressure-Lowering Effects in Spontaneously Hypertensive Rats

PubMed Central

Nwachukwu, Ifeanyi D.; Girgih, Abraham T.; Malomo, Sunday A.; Onuh, John O.; Aluko, Rotimi E.

2014-01-01

Thermoase-digested flaxseed protein hydrolysate (FPH) samples and ultrafiltration membrane-separated peptide fractions were initially evaluated for in vitro inhibition of angiotensin I-converting enzyme (ACE) and renin activities. The two most active FPH samples and their corresponding peptide fractions were subsequently tested for in vivo antihypertensive activity in spontaneously hypertensive rats (SHR). The FPH produced with 3% thermoase digestion showed the highest ACE- and renin-inhibitory activities. Whereas membrane ultrafiltration resulted in significant (p < 0.05) increases in ACE inhibition by the <1 and 1–3 kDa peptides, only a marginal improvement in renin-inhibitory activity was observed for virtually all the samples after membrane ultrafiltration. The FPH samples and membrane fractions were also effective in lowering systolic blood pressure (SBP) in SHR with the largest effect occurring after oral administration (200 mg/kg body weight) of the 1–3 kDa peptide fraction of the 2.5% FPH and the 3–5 kDa fraction of the 3% FPH. Such potent SBP-lowering capacity indicates the potential of flaxseed protein-derived bioactive peptides as ingredients for the formulation of antihypertensive functional foods and nutraceuticals. PMID:25302619

Ceramic membrane by tape casting and sol-gel coating for microfiltration and ultrafiltration application

NASA Astrophysics Data System (ADS)

Das, Nandini; Maiti, H. S.

2009-11-01

Alumina membrane filters in the form of thin (0.3-0.8 mm) discs of 25-30 mm diameter suitable for microfiltration application have been fabricated by tape-casting technique. Further using this microfiltration membrane as substrate, boehmite sol coating was applied on it and ultrafiltration membrane with very small thickness was formed. The pore size of the microfiltration membrane could be varied in the range of 0.1-0.7 μm through optimisation of experimental parameter. In addition, each membrane shows a very narrow pore size distribution. The most important factor, which determines the pore size of the membrane, is the initial particle size and its distribution of the ceramic powder. The top thin ultrafiltration, boehmite layer was prepared by sol-gel method, with a thickness of 0.5 μm. Particle size of the sol was approximately 30-40 nm. The structure and formation of the layer was analysed through TEM. At 550 °C formation of the top layer was completed. The pore size of the ultrafiltration membrane measured from TEM micrograph was almost 10 nm. Results of microbial (Escherichia coli—smallest-sized water-borne bacteria) test confirm the possibility of separation through this membrane

Peritoneal fluid transport: mechanisms, pathways, methods of assessment.

PubMed

Waniewski, Jacek

2013-11-01

Fluid removal during peritoneal dialysis is controlled by many mutually dependent factors and therefore its analysis is more complex than that of the removal of small solutes used as markers of dialysis adequacy. Many new tests have been proposed to assess quantitatively different components of fluid transport (transcapillary ultrafiltration, peritoneal absorption, free water, etc.) and to estimate the factors that influence the rate of fluid transport (osmotic conductance). These tests provide detailed information about indices and parameters that describe fluid transport, especially those concerning the problem of the permanent loss of ultrafiltration capacity (ultrafiltration failure). Different theories and respective mathematical models of mechanisms and pathways of fluid transport are presently discussed and applied, and some fluid transport issues are still debated. Copyright © 2013 IMSS. Published by Elsevier Inc. All rights reserved.

The determination of ultrafiltrable calcium and magnesium in serum.

PubMed

Danielson, B G; Pallin, E; Sohtell, M

1982-01-01

Ultrafiltrate of human serum was investigated in order to evaluate the serum content of calcium and magnesium. The acid and base concentrations and pH of the serum was altered through titration with HCl- or NaOH-solutions. The Pco2 was varied in the titrated serum using different carbon dioxide tensions. This was performed when serum was filtered in a recycling system. It is shown that the analysis of calcium and magnesium have to be done under anaerobic conditions or at standardized pH and Pco2 situations, as the concentrations vary with both pH and Pco2. The concentration ratio between ultrafiltrate and serum for calcium and magnesium was found to be 0.56 and 0.74 respectively at pH=7.41 and Pco2=40 mmHg.

High-throughput protein concentration and buffer exchange: comparison of ultrafiltration and ammonium sulfate precipitation.

PubMed

Moore, Priscilla A; Kery, Vladimir

2009-01-01

High-throughput protein purification is a complex, multi-step process. There are several technical challenges in the course of this process that are not experienced when purifying a single protein. Among the most challenging are the high-throughput protein concentration and buffer exchange, which are not only labor-intensive but can also result in significant losses of purified proteins. We describe two methods of high-throughput protein concentration and buffer exchange: one using ammonium sulfate precipitation and one using micro-concentrating devices based on membrane ultrafiltration. We evaluated the efficiency of both methods on a set of 18 randomly selected purified proteins from Shewanella oneidensis. While both methods provide similar yield and efficiency, the ammonium sulfate precipitation is much less labor intensive and time consuming than the ultrafiltration.

Dental handpiece contamination: a proteomics and surface analysis approach.

PubMed

Smith, Andrew; Smith, Gordon; Lappin, David F; Baxter, Helen C; Jones, Anita; Baxter, Robert L

2014-01-01

Dental handpieces (DHPs) become biofouled internally with patient derived material that is difficult to access for removal and inactivation. This study undertook a quantitative and qualitative investigation of protein contamination of internal components from three different types of DHP: the turbine, slow speed contra-angle and surgical. Eluates from the high speed turbine, low speed spray channels and surgical gear were assayed for protein using an orthophthaldehyde assay. Eluates concentrated by Amicon ultrafiltration were also analysed by SDS-PAGE, mass spectroscopy, Western blotting and ELISA. The surfaces of handpiece components were also investigated by SEM, EFSCAN and EDAX microscopy. Surgical gears contained highest levels of protein (403 μg), followed by low speed spray channels (17.7 μg) and the high speed turbine (<5 μg). Mass spectroscopy of surgical gears demonstrated mostly serum derived proteins. Decontamination of the DHPs using an automated washer disinfector and handpiece irrigator showed a significant reduction in residual protein levels.

Hollow-Fiber Ultrafiltration and PCR Detection of Human-Associated Genetic Markers from Various Types of Surface Water in Florida ▿

PubMed Central

Leskinen, Stephaney D.; Brownell, Miriam; Lim, Daniel V.; Harwood, Valerie J.

2010-01-01

Hollow-fiber ultrafiltration (HFUF) and PCR were combined to detect human-associated microbial source tracking marker genes in large volumes of fresh and estuarine Florida water. HFUF allowed marker detection when membrane filtration did not, demonstrating HFUF's ability to facilitate detection of diluted targets by PCR in a variety of water types. PMID:20435774

Neuronal Networks in Children with Continuous Spikes and Waves during Slow Sleep

ERIC Educational Resources Information Center

Siniatchkin, Michael; Groening, Kristina; Moehring, Jan; Moeller, Friederike; Boor, Rainer; Brodbeck, Verena; Michel, Christoph M.; Rodionov, Roman; Lemieux, Louis; Stephani, Ulrich

2010-01-01

Epileptic encephalopathy with continuous spikes and waves during slow sleep is an age-related disorder characterized by the presence of interictal epileptiform discharges during at least greater than 85% of sleep and cognitive deficits associated with this electroencephalography pattern. The pathophysiological mechanisms of continuous spikes and…

A mass balance approach for calculation of recovery and binding enables the use of ultrafiltration as a rapid method for measurement of plasma protein binding for even highly lipophilic compounds.

PubMed

Wang, Changguang; Williams, Noelle S

2013-03-05

The aim of this study is to further validate the use of ultrafiltration (UF) as a method for determining plasma protein binding (PPB) by demonstrating that non-specific binding (NSB) is not a limitation, even for highly lipophilic compounds, because NSB sites on the apparatus are passivated in the presence of plasma. Mass balance theory was used to calculate recovery of 20 commercial and seven investigational compounds during ultrafiltration in the presence and absence of plasma. PPB was also measured using this mass balance approach for comparison to PPB determined by rapid equilibrium dialysis (RED) and as found in the literature. Compound recovery during UF was dramatically different in the presence and absence of plasma for compounds with high NSB in PBS only. A comparison of PPB calculated by ultrafiltration with literature values or calculated by RED gave concordant results. Discrepancies could be explained by changes in pH, insufficient time to equilibrium, or compound instability during RED, problems which were circumvented by ultrafiltration. Therefore, NSB, as measured by the traditional incubation of compound in PBS, need not be an issue when choosing UF as a PPB assay method. It is more appropriate to calculate compound recovery from the device in plasma as measured by mass balance to determine the suitability of the method for an individual compound. The speed with which UF can be conducted additionally avoids changes in pH or compound loss that can occur with other methods. The mass balance approach to UF is thus a preferred method for rapid determination of PPB. Copyright © 2012 Elsevier B.V. All rights reserved.

The processing of used cooking oil (yellow grease) using combination of adsorption and ultrafiltration membrane processes

NASA Astrophysics Data System (ADS)

Rosnelly, C. M.; Sofyana; Amalia, D.; Sarah, S.

2018-03-01

Yellow grease is used cooking oil whose quality has degraded due to the oxidation, polymerization, or hydrolysis process. In previous studies, yellow grease refining had been conducted either by adsorption or by using membrane. In this study, adsorption process using adsorbent from bagasse activated with H3PO4 12.5%, and ultrafiltration using Polyethersulfone (PES) membrane were combined. In adsorption stage, several variation of bagasse mass was fed into 200 ml of yellow grease and stirred for 60 minutes at 60 rpm. Yellow grease produced from adsorption with best condition was then processed using ultrafiltration membran that is PES membran with concentration by 15 wt % with transmembrane pressure variation by 0.5; 1; 1.5; 2; and 2.5 Bar. Analysis of yellow grease characteristics before refined showed its acid number, peroxide number, iodine number, and water content respectively by 2.68 mgKOH/Kg; 5.97 Meq/Kg; 51,48; and 1.29%. Characteristics of yellow grease after adsorption at its best condition on the parameters of acid number, peroxide number, iodine number, and water content are respectively by 2.55 mgKOH/Kg; 4.19 Meq/Kg; 40,02; and 0.27%. Characteristics of yellow grease after ultrafiltration at its best condition on the parameters of acid number, peroxide number, iodine number, and water content are respectively by 1.12 mgKOH/Kg; 1.8 Meq/Kg; 41,36; and 0.02%. Combination of adsorption and ultrafiltration processes for yellow grease processing showed decreasing value on the parameters of acid number, peroxide number, and water content that conforms to the SNI quality standard, but has not been able to increase the iodine number.

Icodextrin as salvage therapy in peritoneal dialysis patients with refractory fluid overload

PubMed Central

Johnson, David Wayne; Arndt, Mary; O'Shea, Amanda; Watt, Rhonda; Hamilton, Jan; Vincent, Kaia

2001-01-01

Background Icodextrin is a high molecular weight, starch-derived glucose polymer, which is capable of inducing sustained ultrafiltration over prolonged (12–16 hour) peritoneal dialysis (PD) dwells. The aim of this study was to evaluate the ability of icodextrin to alleviate refractory, symptomatic fluid overload and prolong technique survival in PD patients. Methods A prospective, open-label, pre-test/post-test study was conducted in 17 PD patients (8 females/9 males, mean age 56.8 ± 2.9 years) who were on the verge of being transferred to haemodialysis because of symptomatic fluid retention that was refractory to fluid restriction, loop diuretic therapy, hypertonic glucose exchanges and dwell time optimisation. One icodextrin exchange (2.5 L 7.5%, 12-hour dwell) was substituted for a long-dwell glucose exchange each day. Results Icodextrin significantly increased peritoneal ultrafiltration (885 ± 210 ml to 1454 ± 215 ml, p < 0.05) and reduced mean arterial pressure (106 ± 4 to 96 ± 4 mmHg, p < 0.05), but did not affect weight, plasma albumin concentration, haemoglobin levels or dialysate:plasma creatinine ratio. Diabetic patients (n = 12) also experienced improved glycaemic control (haemoglobin Alc decreased from 8.9 ± 0.7% to 7.9 ± 0.7%, p < 0.05). Overall PD technique survival was prolonged by a mean of 11.6 months (95% CI 6.0–17.3 months). On multivariate Cox proportional hazards analysis, extension of technique survival by icodextrin was only significantly predicted by baseline net daily peritoneal ultrafiltration (adjusted HR 2.52, 95% CI 1.13–5.62, p < 0.05). Conclusions Icodextrin significantly improved peritoneal ultrafiltration and extended technique survival in PD patients with symptomatic fluid overload, especially those who had substantially impaired peritoneal ultrafiltration. PMID:11737871

Reverse osmosis and ultrafiltration for recovery and reuse of larval rearing water in Anopheles arabiensis mass production: Effect of water quality on larval development and fitness of emerging adults.

PubMed

Mamai, Wadaka; Hood-Nowotny, Rebecca; Maiga, Hamidou; Ali, Adel Barakat; Bimbile-Somda, Nanwintoun S; Soma, Diloma Dieudonné; Yamada, Hanano; Lees, Rosemary Susan; Gilles, Jeremie R L

2017-06-01

Countries around the world are showing increased interest in applying the sterile insect technique against mosquito disease vectors. Many countries in which mosquitoes are endemic, and so where vector control using the sterile insect technique may be considered, are located in arid zones where water provision can be costly or unreliable. Water reuse provides an alternate form of water supply. In order to reduce the cost of mass rearing of Anopheles arabiensis mosquitoes, the possibility of recycling and reusing larval rearing water was explored. The used rearing water ('dirty water') was collected after the tilting of rearing trays for collection of larvae/pupae, and larvae/pupae separation events and underwent treatment processes consisting of ultrafiltration and reverse osmosis. First-instar An. arabiensis larvae were randomly assigned to different water-type treatments, 500 larvae per laboratory rearing tray: 'clean' dechlorinated water, routinely used in rearing; dirty water; and 'recycled' dirty water treated using reverse osmosis and ultrafiltration. Several parameters of insect quality were then compared: larval development, pupation rate, adult emergence, body size and longevity. Water quality of the samples was analyzed in terms of ammonia, nitrite, nitrate, sulphate, dissolved oxygen, chloride, and phosphate concentrations after the larvae had all pupated or died. Surface water temperatures were also recorded continuously during larval development. Pupation rates and adult emergence were similar in all water treatments. Adult body sizes of larvae reared in recycled water were similar to those reared in clean water, but larger than those reared in the dirty larval water treatment, whereas the adult longevity of larvae reared in recycled water was significantly increased relative to both 'clean' and 'dirty' water. Dirty larval water contained significantly higher concentrations of ammonium, sulfate, phosphate and chloride and lower levels of dissolved oxygen than clean water. These parameters significantly varied during the period of larval development. After dirty water was recycled by ultrafiltration and reverse osmosis, all the parameters measured were the same as those in clean water. This study demonstrated the potential for using recycled larval rearing water to supplement clean dechlorinated water supplies. Recycling used water improved its quality and of the reared mosquitoes. As water demands and environmental pressures grow, recycling of larval rearing water will improve the sustainability and affordability of mosquito mass-rearing. Copyright © 2017 Elsevier B.V. All rights reserved.

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT - PHYSICAL REMOVAL OF MICROBIOLOGICAL AND PARTICULATE CONTAMINANTS IN DRINKING WATER, HYDRANAUTICS HYDRACAP ULTRAFILTRATION MEMBRANE SYSTEM AT THE AQUA2000 RESEARCH CENTER - NSF 00/04/EPADW395

EPA Science Inventory

Verification testing of the Hydranautics HYDRA Cap(TM) Ultrafiltration Membrane System (Hydranautics UF unit) was conducted over two test periods at the Aqua 2000 Research Center in San Diego, CA. The first test period, from 8/3/99-9/13/99, represented summer/fall conditions. The...

ETV REPORT - PHYSICAL REMOVAL OF CRYPTOSPORIDIUM OOCYSTS AND GIARDIA CYSTS IN DRINKING WATER AQUASOURCE NORTH AMERICA ULTRAFILTRATION SYSTEM A35 AT PITTSBURGH, PA. - NSF00/07/EPADW395

EPA Science Inventory

Verification testing of the Aquasource Ultrafiltration Treatment System Model A35 was conducted from 12/1 - 12/31/98. The treatment system underwent microbial challenge testing on 1/22/99 and demonstrated a 5.5 log10 removal of Giardia cysts and a 6.5 log10 removal of Cryptospori...

Tangential-flow ultrafiltration with integrated inhibition detection for recovery of surrogates and human pathogens from large-volume source water and finished drinking water.

PubMed

Gibson, Kristen E; Schwab, Kellogg J

2011-01-01

Tangential-flow ultrafiltration was optimized for the recovery of Escherichia coli, Enterococcus faecalis, Clostridium perfringens spores, bacteriophages MS2 and PRD1, murine norovirus, and poliovirus seeded into 100-liter surface water (SW) and drinking water (DW) samples. SW and DW collected from two drinking water treatment plants were then evaluated for human enteric viruses.

Comparison of 2 ultrafiltration systems for the concentration of seeded viruses from environmental waters.

PubMed

Olszewski, John; Winona, Linda; Oshima, Kevin H

2005-04-01

The use of ultrafiltration as a concentration method to recover viruses from environmental waters was investigated. Two ultrafiltration systems (hollow fiber and tangential flow) in a large- (100 L) and small-scale (2 L) configuration were able to recover greater than 50% of multiple viruses (bacteriophage PP7 and T1 and poliovirus type 2) from varying water turbidities (10-157 nephelometric turbidity units (NTU)) simultaneously. Mean recoveries (n = 3) in ground and surface water by the large-scale hollow fiber ultrafiltration system (100 L) were comparable to recoveries observed in the small-scale system (2 L). Recovery of seeded viruses in highly turbid waters from small-scale tangential flow (2 L) (screen and open channel) and hollow fiber ultrafilters (2 L) (small pilot) were greater than 70%. Clogging occurred in the hollow fiber pencil module and when particulate concentrations exceeded 1.6 g/L and 5.5 g/L (dry mass) in the screen and open channel filters, respectively. The small pilot module was able to filter all concentrates without clogging. The small pilot hollow fiber ultrafilter was used to test recovery of seeded viruses from surface waters from different geographical regions in 10-L volumes. Recoveries >70% were observed from all locations.

Determination of moxifloxacin in human plasma, plasma ultrafiltrate, and cerebrospinal fluid by a rapid and simple liquid chromatography- tandem mass spectrometry method.

PubMed

Pranger, Arianna D; Alffenaar, Jan-Willem C; Wessels, A Mireille A; Greijdanus, Ben; Uges, Donald R A

2010-04-01

Moxifloxacin (MFX) is a useful agent in the treatment of multi-drug-resistant tuberculosis (MDR-TB). At Tuberculosis Centre Beatrixoord, a referral center for tuberculosis in the Netherlands, approximately 36% of the patients have received MFX as treatment. Based on the variability of MFX AUC, the variability of in vitro susceptibility to MFX of M. tuberculosis, and the variability of penetration into sanctuary sites, measuring the concentration of MFX in plasma and cerebrospinal fluid (CSF) could be recommended. Therefore, a rapid and validated liquid chromatography-tandem mass spectrometry (LC-MS-MS) analyzing method with a simple pretreatment procedure was developed for therapeutic drug monitoring of MFX in human plasma and CSF. Because of the potential influence of protein binding on efficacy, we decided to determine both bound and unbound (ultrafiltrate) fraction of MFX. The calibration curves were linear in the therapeutic range of 0.05 to 5.0 mg/L plasma and CSF with CV in the range of -5.4% to 9.3%. MFX ultrafiltrate samples could be determined with the same method setup for analysis of MFX in CSF. The LC-MS-MS method developed in this study is suitable for monitoring MFX in human plasma, plasma ultrafiltrate, and CSF.

Acute symptoms during and between hemodialysis: the relative role of speed, duration, and biocompatibility of dialysis.

PubMed

Skroeder, N R; Jacobson, S H; Lins, L E; Kjellstrand, C M

1994-12-01

The relationship between hemodialysis (HD) symptoms and dialyzer membrane composition and area, blood-flow, treatment duration, urea removal, ultrafiltration volume, leukocyte activation, and complement generation (C3a) was studied in 20 patients undergoing 234 HD treatments by 12 different modes in random order using Cuprophan, hemophane, or polyamide membranes with small or large membrane areas with high Qb (400 ml/min) and short duration (2 h) or low Qb (200 ml/min) and long duration (4 h). Fewer symptoms occurred during the 2-h HD at high Qb than during the 4-h HD with low Qb (19% vs. 32%, p = 0.0351). No differences were observed between different dialyzer membranes or areas. More intradialytic symptoms occurred when urea elimination was high than it was low (p = 0.0044). Leukocyte activation (leukocyte drop) after 15 min of dialysis and complement generation did not influence symptom incidence. Blood pressure changes were mainly influenced by ultrafiltration volume (p < 0.001). Symptoms between dialyses were determined by urea removal and ultrafiltration. Membrane, area, or Qb were of no importance. Thus, duration of dialysis, urea removal, and demand for ultrafiltration, but not membrane composition, area, or biocompatability, are important for the development of HD-related symptoms.

Flux enhancement during ultrafiltration of produced water using turbulence promoter.

PubMed

Zhen, Xiang-hua; Yu, Shui-li; Wang, Bei-fu; Zheng, Hai-feng

2006-01-01

Concentration polarization and membrane fouling remain one of the major hurdles for the implementation of ultrafiltration of produced water. Although many applications for ultrafiltration were already suggested, only few were implemented on an industrial scale. Among those techniques, turbulence promoter can be more simple and effective in overcoming membrane fouling and enhancing membrane flux. As for the result that turbulence promoter increase fluid velocity, wall shear rates and produce secondary flows or instabilities, the influence of turbulence promoter was investigated on permeate flux during produced water ultrafiltration and the potential application of this arrangement for an industrial development. Experimental investigations were performed on 100 KDa molecular weight cut-off PVDF single-channel tubular membrane module using four kinds of turbulence promoters. It is observed that the significant flux enhancement in the range of 83%-164% was achieved while the hydraulic dissipated power per unit volume of permeate decreased from 31%-42%, which indicated that the using of turbulence promoter is more efficient than operation without the turbulence promoter. The effects of transmembrane pressure and cross-flow velocity with and without turbulence promoter were studied as well. Among the four kinds of turbulence promoters, winding inserts with 20.0 mm pitch and 1.0 mm wire diameter showed better performances than the others did.

Exploration of zwitterionic cellulose acetate antifouling ultrafiltration membrane for bovine serum albumin (BSA) separation.

PubMed

Liu, Yang; Huang, Haitao; Huo, Pengfei; Gu, Jiyou

2017-06-01

This study focused on the preparation of a new kind of membrane material, zwitterionic cellulose acetate (ZCA), via a three-step procedure consist of oxidization, Schiff base and quaternary amination reaction, and the fabrication of antifouling ZCA ultrafiltration membrane by the non-solvent-induced phase separation method (NIPS). The morphologies, surface chemical structures and compositions of the obtained CA and ZCA membranes were thoroughly characterized by field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray (EDX) spectroscopy, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), respectively. Meanwhile, the thermal stability, porosity and average pore size of two investigated membranes were also studied. As a result, the ZCA membrane displayed significantly improved hydrophilicity and water permeability compared with those of the reference CA membrane, despite a slight decrease in the protein rejection ratio. According to the cycle ultrafiltration performance of bovine serum albumin (BSA) solution and protein adsorption experiment, ZCA membrane exhibited better flux recovery property and fouling resistant ability, especially irreversible fouling resistant ability, suggesting superior antifouling performance. This new approach gives polymer-based membrane a long time life and excellent ultrafiltration performance, and seems promising for potential applications in the protein separation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Perfusion Techniques Toward Bloodless Pediatric Open Heart Surgery

PubMed Central

Olshove, Vincent F.; Preston, Thomas; Gomez, Daniel; Phillips, Alistair; Galantowicz, Mark

2010-01-01

Abstract: There continues to be evidence regarding the negative impact of blood transfusion on morbidity and mortality in the adult literature, including infection risk, increased hospital and intensive care length of stay, and costs. More effort has been put into reducing the use of blood components in adult surgical centers but blood transfusions continue to be used frequently in pediatric centers. From 2002 through 2005, we embarked on a mission of reduced prime volume in an effort toward bloodless cardiac surgery to meet the needs of the Jehovah’s Witness patient. The same bloodless surgical and perfusion techniques were applied to all patients undergoing cardiopulmonary bypass beginning in 2006. Circuit size was minimized and acute normovolemic hemodilution (ANH) was considered and attempted more often, especially if a re-operation. Retrograde arterial prime (RAP) and venous antegrade prime (VAP), dilutional or balanced ultrafiltration during cardiopulmonary bypass, modified arteriovenous ultrafiltration post bypass, and cell salvage of remaining circuit contents after flushing with crystalloid were recorded. ANH, RAP, and VAP, separately or in combination, were used less than 1% of the time prior to 2006. From 2006–2008 ANH was performed on 42% of the patients and RAP/VAP was performed on 70% of the patients. From 2006–2008, 43% (287 of 662) of the open heart surgeries were performed bloodless in the operating room versus 30% (193 of 633) from 2003–2005. Bloodless surgery more than doubled for the 0–6, 6–15, and 15–20 kg groups from 3.5%, 23%, and 23% respectively in 2003–2005 to 9%, 44%, and 58%, respectively in 2006–2008. With the cooperation of the entire cardiac surgical team, bloodless open heart surgery is achievable in a pediatric cardiac surgical center, including neonates. PMID:20648896

The effect of low-GDP solution on ultrafiltration and solute transport in continuous ambulatory peritoneal dialysis patients.

PubMed

Cho, Kyu-Hyang; Do, Jun-Young; Park, Jong-Won; Yoon, Kyung-Woo; Kim, Yong-Lim

2013-01-01

Several studies have reported benefits for human peritoneal mesothelial cell function of a neutral-pH dialysate low in glucose degradation products (GDPs). However, the effects of low-GDP solution on ultrafiltration (UF), transport of solutes, and control of body water remain elusive. We therefore investigated the effect of low-GDP solution on UF, solute transport, and control of body water. Among 79 new continuous ambulatory peritoneal dialysis (CAPD) patients, 60 completed a 12-month protocol (28 in a lactate-based high-GDP solution group, 32 in a lactate-based low-GDP solution group). Clinical indices--including 24-hour UF volume (UFV), 24-hour urine volume (UV), residual renal function, and dialysis adequacy--were measured at months 1, 6, and 12. At months 1, 6, and 12, UFV, glucose absorption, 4-hour dialysate-to-plasma (D/P) creatinine, and 1-hour D/P Na(+) were assessed during a modified 4.25% peritoneal equilibration test (PET). Body composition by bioelectric impedance analysis was measured at months 1 and 12 in 26 CAPD patients. Daily UFV was lower in the low-GDP group. Despite similar solute transport and aquaporin function, the low-GDP group also showed lower UFV and higher glucose absorption during the PET. Factors associated with UFV during the PET were lactate-based high-GDP solution and 1-hour D/P Na(+). No differences in volume status and obesity at month 12 were observed, and improvements in hypervolemia were equal in both groups. Compared with the high-GDP group, the low-GDP group had a lower UFV during a PET and a lower daily UFV during the first year after peritoneal dialysis initiation. Although the low-GDP group had a lower daily UFV, no difficulties in controlling edema were encountered.

Enhancing performance and surface antifouling properties of polysulfone ultrafiltration membranes with salicylate-alumoxane nanoparticles

NASA Astrophysics Data System (ADS)

Mokhtari, Samaneh; Rahimpour, Ahmad; Shamsabadi, Ahmad Arabi; Habibzadeh, Setareh; Soroush, Masoud

2017-01-01

To improve the hydrophilicity and antifouling properties of polysulfone (PS) ultrafiltration membranes, we studied the use of salicylate-alumoxane (SA) nanoparticles as a novel hydrophilic additive. The effects of SA nanoparticles on the membrane characteristics and performance were investigated in terms of membrane structure, permeation flux, solute rejection, hydrophilicity, and antifouling ability. The new mixed-matrix membranes (MMMs) possess asymmetric structures. They have smaller finger-like pores and smoother surfaces than the neat PS membranes. The embedment of SA nanoparticles in the polymer matrix and the improvement of surface hydrophilicity were investigated. Ultrafiltration experiments indicated that the pure-water flux of the new MMMs initially increases with SA nanoparticles loading followed by a decrease at high loadings. Higher BSA solution flux was achieved for the MMMs compared to the neat PS membranes. Membranes with 1 wt.% SA nanoparticles exhibit the highest flux recovery ratio of 87% and the lowest irreversible fouling of 13%.

Novelties of combustion synthesized titania ultrafiltration membrane in efficient removal of methylene blue dye from aqueous effluent.

PubMed

Doke, Suresh M; Yadav, Ganapati D

2014-12-01

In this study, titania nanoparticles were synthesized by combustion and used to make ultrafiltration membrane. Characteristics of titania membranes such as textural evaluation, surface morphology, pure water permeability and protein rejection were investigated. Titania membrane sintered at 450 °C showed pure water permeability 11 × 10−2 L h−1 m−2 kPa−1 and 76% protein rejection. The membrane presented good water flux and retention properties with regards to protein and methylene blue dye. Ultrafiltration process was operated at lower pressure (100 kPa) and showed 99% removal of methylene blue using adsorptive micellar flocculation at sodium dodecyl sulfate concentration below its critical micellar concentration. Ferric chloride was used as the coagulant. The method of making titania membrane and its use are new. These studies can be extended to other dyes and pollutants.

Enhanced permeability and antifouling performance of cellulose acetate ultrafiltration membrane assisted by l-DOPA functionalized halloysite nanotubes.

PubMed

Mu, Keguang; Zhang, Dalun; Shao, Ziqiang; Qin, Dujian; Wang, Yalong; Wang, Shuo

2017-10-15

l-Dopa functionalized halloysite nanotubes (HNTs) were prepared by the self-polymerization of l-dopa in the weak alkaline condition. Then different contents of l-dopa coated HNTs (LPDHNTs) were blended into cellulose acetate to prepare enhanced performance ultrafiltration membranes via the phase inversion method. The HNTs and LPDHNTs were characterized by FTIR, XPS, and TEM anysis. And the membranes morphologies, separation performance, antifouling performance, mechanical properties and hydrophilicity were also investigated. It was found that the composite membranes exhibited excellent antifouling performance. The pure water flux of 3.0wt% LPDHNTs/CA membrane increased from 11.4Lm -2 h -1 to 92.9Lm -2 h -1 , while the EA rejection ratio of the membrane was about 91.2%. In addition, the mechanical properties of the resultant membranes were strengthened compared with the CA ultrafiltration membrane. Copyright © 2017 Elsevier Ltd. All rights reserved.

The composition and compression of biofilms developed on ultrafiltration membranes determine hydraulic biofilm resistance.

PubMed

Derlon, Nicolas; Grütter, Alexander; Brandenberger, Fabienne; Sutter, Anja; Kuhlicke, Ute; Neu, Thomas R; Morgenroth, Eberhard

2016-10-01

This study aimed at identifying how to improve the level of permeate flux stabilisation during gravity-driven membrane filtration without control of biofilm formation. The focus was therefore on understanding (i) how the different fractions of the biofilms (inorganics particles, bacterial cells, EPS matrix) influence its hydraulic resistance and (ii) how the compression of biofilms impacts its hydraulic resistance, i.e., can water head be increased to increase the level of permeate flux stabilisation. Biofilms were developed on ultrafiltration membranes at 88 and 284 cm water heads with dead-end filtration for around 50 days. A larger water head resulted in a smaller biofilm permeability (150 and 50 L m(-2) h(-1) bar(-1) for biofilms grown at 88 cm and 284 cm water head, respectively). Biofilms were mainly composed of EPS (>90% in volume). The comparison of the hydraulic resistances of biofilms to model fouling layers indicated that most of the hydraulic resistance is due to the EPS matrix. The compressibility of the biofilm was also evaluated by subjecting the biofilms to short-term (few minutes) and long-term variations of transmembrane pressures (TMP). A sudden change of TMP resulted in an instantaneous and reversible change of biofilm hydraulic resistance. A long-term change of TMP induced a slow change in the biofilm hydraulic resistance. Our results demonstrate that the response of biofilms to a TMP change has two components: an immediate variation of resistance (due to compression/relaxation) and a long-term response (linked to biofilm adaptation/growth). Our results provide relevant information about the relationship between the operating conditions in terms of TMP, the biofilm structure and composition and the resulting biofilm hydraulic resistance. These findings have practical implications for a broad range of membrane systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of Conversion to a Bicarbonate/Lactate-Buffered, Neutral-pH, Low-GDP PD Regimen in Prevalent PD: A 2-Year Randomized Clinical Trial.

PubMed

Farhat, Karima; Douma, Caroline E; Ferrantelli, E; Ter Wee, Pieter M; Beelen, Robert H J; van Ittersum, Frans J

2017-01-01

♦ BACKGROUND: The use of pH-neutral peritoneal dialysis (PD) fluids low in glucose degradation products (GDP) may better preserve the peritoneal membrane and have fewer systemic effects. The effects of conversion from conventional to neutral-pH, low-GDP PD fluids in prevalent patients are unclear. Few studies on the role of neutral-pH, low-GDP PD have studied residual renal function, ultrafiltration, peritonitis incidence and technique failure, transport characteristics, and local and systemic markers of inflammation in prevalent PD patients. ♦ METHODS: In a multi-center open-label randomized clinical trial (RCT), we randomly assigned 40 of 78 stable continuous ambulatory PD (CAPD) and automated PD (APD) patients to treatment with bicarbonate/lactate, neutral-pH, low-GDP PD fluid (Physioneal; Baxter Healthcare Corporation, Deerfield, IL, USA) and compared them with 38 patients continuing their current standard lactate-buffered PD fluid (PDF) (Dianeal; Baxter Healthcare Corporation, Deerfield, IL, USA) during 2 years. Primary outcome was residual renal function (RRF) and ultrafiltration (UF) during peritoneal equilibration test (PET); peritonitis incidence was a secondary outcome. Furthermore, clinical parameters as well as several biomarkers in effluents and serum were measured. ♦ RESULTS: During follow-up, RRF did not differ between the groups. In the Physioneal group ultrafiltration (UF) during PET remained more or less stable (-20 mL [confidence interval (CI): -163.5 - 123.5 mL]; p = 0.7 over 24 months), whereas it declined in the Dianeal group (-243 mL [CI: -376.6 to -109.4 mL]; p < 0.0001 over 24 months), resulting in a difference of 233.7 mL [95% CI 41.0 - 425.5 mL]; p = 0.017 between the groups at 24 months. The peritonitis rate was lower in the Physioneal group: adjusted odds ratio (OR) 0.38 (0.15 - 0.97) p = 0.043. No differences were observed between the 2 groups in peritoneal adequacy or transport characteristics nor effluent markers of local inflammation (cancer antigen [CA]125, hyaluronan [HA], vascular endothelial growth factor [VEGF], macrophage chemo-attractant protein [MCP]-1, HA and transforming growth factor [TGF]β-1). ♦ CONCLUSION: In prevalent PD patients, our study did not find a difference in RRF after conversion from conventional to neutral-pH, low-GDP PD fluids, although there is a possibility that the study was underpowered to detect a difference. Decline in UF during standardized PET was lower after 2 years in the Physioneal group. Copyright © 2017 International Society for Peritoneal Dialysis.

Screening a fragment cocktail library using ultrafiltration

PubMed Central

Shibata, Sayaka; Zhang, Zhongsheng; Korotkov, Konstantin V.; Delarosa, Jaclyn; Napuli, Alberto; Kelley, Angela M.; Mueller, Natasha; Ross, Jennifer; Zucker, Frank H.; Buckner, Frederick S.; Merritt, Ethan A.; Verlinde, Christophe L. M. J.; Van Voorhis, Wesley C.; Hol, Wim G. J.; Fan, Erkang

2011-01-01

Ultrafiltration provides a generic method to discover ligands for protein drug targets with millimolar to micromolar Kd, the typical range of fragment-based drug discovery. This method was tailored to a 96-well format, and cocktails of fragment-sized molecules, with molecular masses between 150 and 300 Da, were screened against medical structural genomics target proteins. The validity of the method was confirmed through competitive binding assays in the presence of ligands known to bind the target proteins. PMID:21750879

Plasma ultrafiltrates from Fanconi Anemia patients induces chromosomal breakages in donor lymphocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Emerit, I.; Levy, A.; Pagano, G.

1994-09-01

The present study investigated the occurrence, if any, of transferable clastogenic activity in the plasma from Fanconi Anemia (FA) patients and their families. A total of 13 FA homozygotes, 25 parents, and 12 siblings were studied for their: (a) spontaneous and DEB-induced chromosomal instability, and (b) induction of chromosomal breaks in peripheral blood lymphocytes (PBL) from healthy donors, following exposure to plasma ultrafiltrates from FA subjects, their parents or siblings. Plasma was ultrafiltered through membranes with a cutoff at 10,000 daltons (YM 10 Amicon) and 0.25 ml-aliquote added to PBL from 14 healthy donors. DEB test provided FA confirmatory diagnosis.more » The occurrence of clastogenic factors (CF) was evident in all FA patients, except for one. In two out of three patients, who died during this study, very high CF levels were observed. Clastogenic activity was significantly higher in male than in female patients (p<0.05). No correlation was observed between CF data and spontaneous or DEB-induced chromosomal instability. Ultrafiltrates from parents and siblings showed less CF than FA homozygotes; however, concentration by ultrafiltration through YM 2 (3x to 5x) led to excess clastogenic activity. The control plasmas were lacking CF even after an 8x concentration. The present data suggest that CF formation in the plasma of FA patients is consistent with an in vivo prooxident state in FA.« less

Optimization of the elution buffer and concentration method for detecting hepatitis E virus in swine liver using a nested reverse transcription-polymerase chain reaction and real-time reverse transcription-polymerase chain reaction.

PubMed

Son, Na Ry; Seo, Dong Joo; Lee, Min Hwa; Seo, Sheungwoo; Wang, Xiaoyu; Lee, Bog-Hieu; Lee, Jeong-Su; Joo, In-Sun; Hwang, In-Gyun; Choi, Changsun

2014-09-01

The aim of this study was to develop an optimal technique for detecting hepatitis E virus (HEV) in swine livers. Here, three elution buffers and two concentration methods were compared with respect to enhancing recovery of HEV from swine liver samples. Real-time reverse transcription-polymerase chain reaction (RT-PCR) and nested RT-PCR were performed to detect HEV RNA. When phosphate-buffered saline (PBS, pH 7.4) was used to concentrate HEV in swine liver samples using ultrafiltration, real-time RT-PCR detected HEV in 6 of the 26 samples. When threonine buffer was used to concentrate HEV using polyethylene glycol (PEG) precipitation and ultrafiltration, real-time RT-PCR detected HEV in 1 and 3 of the 26 samples, respectively. When glycine buffer was used to concentrate HEV using ultrafiltration and PEG precipitation, real-time RT-PCR detected HEV in 1 and 3 samples of the 26 samples, respectively. When nested RT-PCR was used to detect HEV, all samples tested negative regardless of the type of elution buffer or concentration method used. Therefore, the combination of real-time RT-PCR and ultrafiltration with PBS buffer was the most sensitive and reliable method for detecting HEV in swine livers. Copyright © 2014 Elsevier B.V. All rights reserved.

Novel Functional Whey-Based Drinks with Great Potential in the Dairy Industry

PubMed Central

Pereira, Carlos; Gomes, David; Gomez-Zavaglia, Andrea; de Antoni, Graciela

2015-01-01

Summary This work focuses on the production of liquid whey protein concentrates by ultrafiltration followed by thermal denaturation and homogenization of the ultrafiltrated concentrate, as well as on the production of ultrafiltrated permeates concentrated by reverse osmosis. Kefir grains (fresh and thawed) and/or commercial probiotic bacteria were inoculated in both liquid whey protein concentrates and concentrated ultrafiltrated permeates and grown at 25 °C for 24 h for the manufacture of fermented drinks. The physicochemical characterization (pH, titratable acidity, viscosity, and content of total solids, ash, fat and proteins) of the obtained drinks was then assessed and compared. Enumeration of viable microorganisms was carried out immediately after inoculation (at 0 h), during the fermentation period (at 12 and 24 h) and during refrigerated storage (at 48, 168 and 336 h). The fermented drinks showed acceptable physicochemical and sensorial properties, and contained above 7 log CFU/mL of lactococci and lactobacilli and 6 log CFU/mL of yeasts after 14 days of refrigerated storage, which is in agreement with the standards required by international organizations like European Food Safety Authority (EFSA) and Food and Drug Administration (FDA) for products containing probiotics. In summary, the strategy developed in this work contributes to the expansion of the applications of products derived from whey fractionation for the design of novel functional foods. PMID:27904362

Marine microalgae Nannochloropsis oculata biomass harvesting using ultrafiltration in cross-flow mode

NASA Astrophysics Data System (ADS)

Devianto, L. A.; Aprilia, D. N.; Indriani, D. W.; Sukarni, S.; Sumarlan, S. H.; Wibisono, Y.

2018-03-01

Microalgae is a potential bioenergy source. It can grows rapidly, even it could be harvested within 7 days. Harvesting is an important part of microalgae cultivation due to the method used. It should be undamaging toward essential content of microalgae and should produces high yields of biomass. In this study, the harvesting of Nannochloropsis oculata was carried out using capillary ultrafiltration in cross flow mode. This study aims to test ultrafiltration membrane performance in Nannochloropsis oculata harvesting accompanied by Backwash and Non-Backwash modes and to analyse its total lipid content. The harvest was done under 1; 1.5; and 2 bar of trans membrane pressure. Some observed parameters were permeate flux, cell density, biomass recovery, microalgae’s dry weight, yield, and total lipid content. The application of high pressure and backwashed treatment have boosted slurry production time which lead to microalgae’s biomass abundance. The result showed that the best treatment of Nannochloropsis oculata harvesting using capillary ultrafiltration membrane in cross flow mode is under 2 bar of pressure with backwashed treatment. This is the fastest condition to produce slurry within 1800 s with the highest recovery percentage 79.50%, 16.05 × 106 cell/ml of post-treatment cell density, 6.8 grams of biomass’ dry weight, 22.66 % of yield, and 2.52 % of total lipid content.

Novel Functional Whey-Based Drinks with Great Potential in the Dairy Industry.

PubMed

Pereira, Carlos; Henriques, Marta; Gomes, David; Gomez-Zavaglia, Andrea; de Antoni, Graciela

2015-09-01

This work focuses on the production of liquid whey protein concentrates by ultrafiltration followed by thermal denaturation and homogenization of the ultrafiltrated concentrate, as well as on the production of ultrafiltrated permeates concentrated by reverse osmosis. Kefir grains (fresh and thawed) and/or commercial probiotic bacteria were inoculated in both liquid whey protein concentrates and concentrated ultrafiltrated permeates and grown at 25 °C for 24 h for the manufacture of fermented drinks. The physicochemical characterization (pH, titratable acidity, viscosity, and content of total solids, ash, fat and proteins) of the obtained drinks was then assessed and compared. Enumeration of viable microorganisms was carried out immediately after inoculation (at 0 h), during the fermentation period (at 12 and 24 h) and during refrigerated storage (at 48, 168 and 336 h). The fermented drinks showed acceptable physicochemical and sensorial properties, and contained above 7 log CFU/mL of lactococci and lactobacilli and 6 log CFU/mL of yeasts after 14 days of refrigerated storage, which is in agreement with the standards required by international organizations like European Food Safety Authority (EFSA) and Food and Drug Administration (FDA) for products containing probiotics. In summary, the strategy developed in this work contributes to the expansion of the applications of products derived from whey fractionation for the design of novel functional foods.

Laboratory Tests on Post-Filtration Precipitation in the WTP Pretreatment Process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russell, Renee L.; Peterson, Reid A.; Rinehart, Donald E.

Pacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). The Pretreatment Engineering Platform (PEP) was designed, constructed, and operated as part of a plan to respond to issue M12, "Undemonstrated Leaching Processes," of the External Flowsheet Review Team (EFRT) issue response plan (Barnes et al. 2006). The PEP is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, andmore » slurry washing processes. The PEP replicates the WTP leaching processes using prototypic equipment and control strategies. A simplified flow diagram of the PEP system is shown in Figure 1.1. Two operating scenarios are currently being evaluated for the ultrafiltration process (UFP) and leaching operations. The first scenario has caustic leaching performed in the UFP-2 ultrafiltration feed vessels (i.e., vessel UFP-VSL-T02A in the PEP; and vessels UFP-VSL-00002A and B in the WTP PTF). The second scenario has caustic leaching conducted in the UFP-1 ultrafiltration feed preparation vessels (i.e., vessels UFP-VSL-T01A and B in the PEP; vessels UFP-VSL-00001A and B in the WTP PTF).« less

49 CFR 236.813 - Speed, slow.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Speed, slow. 236.813 Section 236.813 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Speed, slow. A speed not exceeding 20 miles per hour. ...

49 CFR 236.813 - Speed, slow.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Speed, slow. 236.813 Section 236.813 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Speed, slow. A speed not exceeding 20 miles per hour. ...

Carbon Nanotubules: Building Blocks for Nanometer-Scale Engineering

NASA Technical Reports Server (NTRS)

Sinnott, Susan B.

1999-01-01

The proposed work consisted of two projects: the investigation of fluid permeation and diffusion through ultrafiltration membranes composed of carbon nanotubules and the design and study of molecular transistors composed of nanotubules. The progress made on each project is summarized and also discussion about additional projects, one of which is a continuation of work supported by another grant, is included. The first project was Liquid Interactions within a Nanotubule Membrane. The second was the design of nanometer-scale hydrocarbon electronic devices. The third was the investigation of Mechanical properties of Nanotubules and Nanotubule bundles. The fourth project was to investigate the growth mechanisms of Carbon Nanotubules.

Ultrafiltration of pegylated proteins

NASA Astrophysics Data System (ADS)

Molek, Jessica R.

There is considerable clinical interest in the use of "second-generation" therapeutics produced by conjugation of a native protein with various polymers including polyethylene glycol (PEG). PEG--protein conjugates, so-called PEGylated proteins, can exhibit enhanced stability, half-life, and bioavailability. One of the challenges in the commercial production of PEGylated proteins is the purification required to remove unreacted polymer, native protein, and in many cases PEGylated proteins with nonoptimal degrees of conjugation. The overall objective of this thesis was to examine the use of ultrafiltration for the purification of PEGylated proteins. This included: (1) analysis of size-based separation of PEGylated proteins using conventional ultrafiltration membranes, (2) use of electrically-charged membranes to exploit differences in electrostatic interactions, and (3) examination of the effects of PEGylation on protein fouling. The experimental results were analyzed using appropriate theoretical models, with the underlying physical properties of the PEGylated proteins evaluated using size exclusion chromatography, capillary electrophoresis, dynamic light scattering, and reverse phase chromatography. PEGylated proteins were produced by covalent attachment of activated PEG to a protein via primary amines on the lysine residues. A simple model was developed for the reaction kinetics, which was used to explore the effect of reaction conditions and mode of operation on the distribution of PEGylated products. The effective size of the PEGylated proteins was evaluated using size exclusion chromatography, with appropriate correlations developed for the size in terms of the molecular weight of the native protein and attached PEG. The electrophoretic mobility of the PEGylated proteins were evaluated by capillary electrophoresis with the data in good agreement with a simple model accounting for the increase in protein size and the reduction in the number of protonated amine groups in the PEGylated proteins. Ultrafiltration experiments were performed using PEGylated alpha-lactalbumin, ovalbumin, and bovine serum albumin. In contrast to the size exclusion chromatography data, the sieving coefficient of the PEGylated proteins depended upon both the number and size of the attached PEG chains due to the elongation or deformation of the PEG associated with the filtrate flux. Sieving coefficients at low filtrate flux were in good agreement with predictions of available hydrodynamic models, with significant elongation occurring when the Deborah number for the PEG chain exceeded 0.001. The effects of electrostatic interactions on the ultrafiltration of PEGylated proteins were examined using electrically-charged membranes generated by covalent attachment of sulphonic acid groups to the base cellulosic membrane. Transmission of PEGylated proteins through charged membranes was dramatically reduced at low ionic strength due to strong electrostatic interactions, despite the presence of the neutral PEG. The experimental results were in good agreement with model calculations developed for the partitioning of charged spheres into charged cylindrical pores. The experimental and theoretical results provide the first quantitative analysis of the effects of PEGylation on transport through semipermeable ultrafiltration membranes. The results from small-scale ultrafiltration experiments were used to develop a two-stage diafiltration process to purify PEGylated alpha-lactalbumin. The first-stage used a neutral membrane to remove the unreacted protein by exploiting differences in size. The second stage used a negatively-charged membrane to remove hydrolyzed PEG, with the PEGylated product retained by strong electrostatic interactions. This process provided a purification factor greater than 1000 with respect to the unreacted protein and greater than 20-fold with respect to the PEG with an overall yield of PEGylated alpha-lactalbumin of 78%. These results provide the first demonstration of the potential of using ultrafiltration for the purification of protein-polymer conjugates.

A validated inductively coupled plasma mass spectrometry (ICP-MS) method for the quantification of total platinum content in plasma, plasma ultrafiltrate, urine and peritoneal fluid.

PubMed

Lemoine, Lieselotte; Thijssen, Elsy; Noben, Jean-Paul; Adriaensens, Peter; Carleer, Robert; Speeten, Kurt Van der

2018-04-15

Oxaliplatin is a platinum (Pt) 1 containing antineoplastic agent that is applied in current clinical practice for the treatment of colon and appendiceal neoplasms. A fully validated, highly sensitive, high throughput inductively coupled plasma mass spectrometry (ICP-MS) method is provided to quantify the total Pt content in plasma, plasma ultrafiltrate, urine and peritoneal fluid. In this ICP-MS approach, the only step of sample preparation is a 1000-fold dilution in 0.5% nitric acid, allowing the analysis of 17 samples per hour. Detection of Pt was achieved over a linear range of 0.01-100 ng/mL. The limit of quantification was 18.0 ng/mL Pt in plasma, 8.0 ng/mL in ultrafiltrate and 6.1 ng/mL in urine and peritoneal fluid. The ICP-MS method was further validated for inter-and intraday precision and accuracy (≤15%), recovery, robustness and stability. Short-term storage of the biofluids, for 14 days, can be performed at -4 °C, -24 °C and -80 °C. As to long-term stability, up to 5 months, storage at -80 °C is encouraged. Furthermore, a timeline assessing the total and unbound Pt fraction in plasma and ultrafiltrate over a period of 45 h is provided. Following an incubation period of 5 h at 37 °C, 19-21% of Pt was recovered in the ultrafiltrate, emphasizing the extensive and rapid binding of oxaliplatin-derived Pt to plasma proteins. The described method can easily be implemented in a routine setting for pharmacokinetic studies in patients treated with oxaliplatin-based hyperthermic intraperitoneal perioperative chemotherapy. Copyright © 2018 Elsevier B.V. All rights reserved.

Development of a Simple and Rapid Method to Measure the Free Fraction of Tacrolimus in Plasma Using Ultrafiltration and LC-MS/MS.

PubMed

Stienstra, Nicolaas A; Sikma, Maaike A; van Dapperen, Anouk L; de Lange, Dylan W; van Maarseveen, Erik M

2016-12-01

Tacrolimus is an immunosuppressant mainly used in the prophylaxis of solid organ transplant rejection. Therapeutic drug monitoring of tacrolimus is essential for avoiding toxicity related to overexposure and transplant rejection from underexposure. Previous studies suggest that unbound tacrolimus concentrations in the plasma may serve as a better predictor of tacrolimus-associated nephrotoxicity and neurotoxicity compared to tacrolimus concentration in whole blood. Monitoring the plasma concentrations of unbound tacrolimus might be of interest in preventing tacrolimus-related toxicity. Therefore, the aim was to develop a method for the measurement of total and unbound tacrolimus concentrations in plasma. The sample preparation for the determination of the plasma concentrations of unbound tacrolimus consisted of an easy-to-use ultrafiltration method followed by solid-phase extraction. To determine the total concentration of tacrolimus in plasma, a simple method based on protein precipitation was developed. The extracts were injected into a Thermo Scientific HyPurity C18 column using gradient elution. The analytes were detected by liquid chromatography-tandem mass spectrometry with positive ionization. The method was validated over a linear range of 1.00-200 ng/L for unbound tacrolimus concentrations in plasma and 100-3200 ng/L for total plasma concentrations. The lower limit of quantification was 1.00 ng/L in ultrafiltrate and 100 ng/L in plasma. The inaccuracy and imprecision for the determination of unbound tacrolimus concentrations in ultrafiltrate and plasma showed a maximum coefficients of variation (CV) of 11.7% and a maximum bias of 3.8%. A rapid and easy method based on ultrafiltration and liquid chromatography-tandem mass spectrometry was established to measure the total and unbound tacrolimus concentrations in plasma. This method can facilitate further investigations on the relationship between plasma concentrations of unbound tacrolimus and clinical outcomes in transplant recipients.

New aspects of the possible sites of ultrafiltration in annelids (oligochaeta).

PubMed

Hansen, U

1995-02-01

Electron microscopic investigations of blood vessels were conducted to show sites of filtration such as podocytes or fenestrated endothelia. The endothelia of the blood vessels of Aelosoma hemprichi, Nais elinguis, Dero obtusa and Enchytraeus buchholzi consist of myoendothelial cells, chloragocytes and podocytes. The podocytes form large archs over a considerable area of the vessels. On the lumen side of the vessel there are several columnar processes which split into numerous small pedicels. The gaps between the adjacent pedicles are bridged by slit membranes. The podocytes are restricted to the front part of the ventral vessel. They are presumed to form a filtration surface. Furthermore, some parts of the ventral vessel are formed by a fenestrated endothelium, mainly in Enchytraeus buchholzi. In the vascular system of E. buchholzi two separate filtration sites were found. Additionally to the filtration site between ventral vessel and coelomic cavity a second filtration site was found in the front part of the body between blood sinus and coelomic cavity. In such areas the basement membrane is the only continuous layer between the blood vessel and the coelomic cavity. Its thickness is in the range of 40 nm. Possible filtration sites in the form of podocytes and irregular fenestrations could be localized at the border between the blood compartment and the coelomic compartment. It can be presumed that the primary urine may be formed by ultrafiltration of blood.

A general diagram for estimating pore size of ultrafiltration and reverse osmosis membranes

NASA Technical Reports Server (NTRS)

Sarbolouki, M. N.

1982-01-01

A slit sieve model has been used to develop a general correlation between the average pore size of the upstream surface of a membrane and the molecular weight of the solute which it retains by better than 80%. The pore size is determined by means of the correlation using the high retention data from an ultrafiltration (UF) or a reverse osmosis (RO) experiment. The pore population density can also be calculated from the flux data via appropriate equations.

"All that glisters is not gold": Ultrafiltration and free thyroxine measurement With apologies to W Shakespeare.

PubMed

Midgley, John E M

2011-02-01

To examine the merits of measuring free analytes by ultrafiltration using either diluted or undiluted serum. Confidence in the accuracy of measurements is affected both by problems identified in current systems using semipermeable membranes, the sensitivity of the system to artefacts and comparisons with other imperfect assays. All "gold standard" methods must robustly obey sound physicochemical principles if valid conclusions are to be drawn. Copyright © 2010 Elsevier Inc. All rights reserved.

A Low Cost Environmentally Benign Waste Lubricants Recycling/Re-refining Technology.

DTIC Science & Technology

1999-05-01

EXPERIMENTAL 3 2.1 Ceramic Membrane Ultrafiltration Pilot Unit 3 2.2 Polishing/Finishing Pilot Unit 3 2.3 Feed Samples 3 2.4 Sample...development of an additional 2 to 3 sites in the US. 2. EXPERIMENTAL 2.1. Ceramic Membrane Ultrafiltration Pilot Unit A photograph of the pilot...scale ceramic membrane system used in this work is shown in Figure la. Samples of spent turbine oil were charged to the feed tank and heated to 150°C

Thresholds and gradients in a semi-arid grassland: long-term grazing treatments induce slow, continuous, and reversible vegetation change

USDA-ARS?s Scientific Manuscript database

Semiarid ecosystems can exhibit non-reversible shifts among alternative stable ecosystem states (thresholds and hysteresis), but can also be characterized by slow, continuous, and reversible changes in plant composition (successional gradients). Conceptual state-and-transition models (STMs) attempt ...

Optimum Detection Of Slow-Frequency-Hopping Signals

NASA Technical Reports Server (NTRS)

Levitt, Barry K.; Cheng, Unjeng

1994-01-01

Two papers present theoretical analyses of various schemes for coherent and noncoherent detection of M-ary-frequency-shift-keyed (MFSK) signals with slow frequency hopping. Special attention focused on continuous-phase-modulation (CPM) subset of SFH/MFSK signals, for which frequency modulation such carrier phase remains continuous (albeit unknown) during each hop.

More Efficient Sodium Removal by Ultrafiltration Compared to Diuretics in Acute Heart Failure; Underexplored and Overstated.

PubMed

Kazory, Amir

2016-01-01

Enhanced removal of sodium has often been cited as an advantage of ultrafiltration (UF) therapy over diuretic-based medical treatment in the management of acute decompensated heart failure. However, so far clinical studies have rarely evaluated the precise magnitude of sodium removal, and this assumption is largely based on the physiologic mechanisms and anecdotal observations that predate the contemporary management of heart failure. Recent data suggest that patients treated with UF experience substantial reduction in urinary sodium excretion possibly due to prolonged intravascular volume contraction. Consequently, the efficient sodium extraction through production of isotonic ultrafiltrate can be offset by urine hypotonicity. Based on the limited currently available data, it seems unlikely that the persistent benefits of UF could be solely explained by its greater efficiency in sodium removal. The design of the future studies should include frequent measurements of urine sodium to precisely compare the impact of UF and diuretics on sodium balance. © 2016 S. Karger AG, Basel.

Ultrafiltration of skimmed goat milk increases its nutritional value by concentrating nonfat solids such as proteins, Ca, P, Mg, and Zn.

PubMed

Moreno-Montoro, Miriam; Olalla, Manuel; Giménez-Martínez, Rafael; Bergillos-Meca, Triana; Ruiz-López, María Dolores; Cabrera-Vique, Carmen; Artacho, Reyes; Navarro-Alarcón, Miguel

2015-11-01

Goat milk has been reported to possess good nutritional and health-promoting properties. Usually, it must be concentrated before fermented products can be obtained. The aim of this study was to compare physicochemical and nutritional variables among raw (RM), skimmed (SM), and ultrafiltration-concentrated skimmed (UFM) goat milk. The density, acidity, ash, protein, casein, whey protein, Ca, P, Mg, and Zn values were significantly higher in UFM than in RM or SM. Dry extract and fat levels were significantly higher in UFM than in SM, and Mg content was significantly higher in UFM than in RM. Ultrafiltration also increased the solubility of Ca and Mg, changing their distribution in the milk. The higher concentrations of minerals and proteins, especially caseins, increase the nutritional value of UFM, which may therefore be more appropriate for goat milk yogurt manufacturing in comparison to RM or SM. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

The Dynamics of Glomerular Ultrafiltration in the Rat

PubMed Central

Brenner, Barry M.; Troy, Julia L.; Daugharty, Terrance M.

1971-01-01

Using a unique strain of Wistar rats endowed with glomeruli situated directly on the renal cortical surface, we measured glomerular capillary pressures using servo-nulling micropipette transducer techniques. Pressures in 12 glomerular capillaries from 7 rats averaged 60 cm H2O, or approximately 50% of mean systemic arterial values. Wave form characteristics for these glomerular capillaries were found to be remarkably similar to those of the central aorta. From similarly direct estimates of hydrostatic pressures in proximal tubules, and colloid osmotic pressures in systemic and efferent arteriolar plasmas, the net driving force for ultrafiltration was calculated. The average value of 14 cm H2O is lower by some two-thirds than the majority of estimates reported previously based on indirect techniques. Single nephron GFR (glomerular filtration rate) was also measured in these rats, thereby permitting calculation of the glomerular capillary ultrafiltration coefficient. The average value of 0.044 nl sec−1 cm H2O−1 glomerulus−1 is at least fourfold greater than previous estimates derived from indirect observations. PMID:5097578

Ultrafiltration and thermal processing effects on Maillard reaction products and biological properties of date palm sap syrups (Phoenix dactylifera L.).

PubMed

Makhlouf-Gafsi, Ines; Krichen, Fatma; Mansour, Riadh Ben; Mokni, Abir; Sila, Assad; Bougatef, Ali; Blecker, Christophe; Attia, Hamadi; Besbes, Souhail

2018-08-01

The effect of ultrafiltration process and temperature concentration on MRPs content and antioxidant, antimicrobial and cytotoxic properties of date palm sap syrups were investigated. MRPs were analyzed by HPLC. Antioxidant activity was evaluated by reducing power and DPPH free radical and H 2 O 2 scavenging activities. Antimicrobial activity was evaluated by the agar disk diffusion method. In vitro cytotoxic activity was examined by cell proliferation assay. Date sap syrups displayed strong antioxidant activities which are correlated 5HMF and 2F contents. In addition, concentration at 100 °C, unlike ultrafiltration process, enhanced significantly the antioxidant activities sap syrups and total phenolic contents. The antimicrobial activities showed marked activity against S. enterica, P. aeruginosa, S. aureus, L. monocytogenes with an inhibition zone of 21, 34, 27 and 34 mm respectively. Cytotoxicity assays showed that sap syrups can inhibit the proliferation of HeLa cell lines at high concentration. Published by Elsevier Ltd.

Study on the interaction of plasma protein binding rate between edaravone and taurine in human plasma based on HPLC analysis coupled with ultrafiltration technique.

PubMed

Tang, Dao-quan; Li, Yin-jie; Li, Zheng; Bian, Ting-ting; Chen, Kai; Zheng, Xiao-xiao; Yu, Yan-yan; Jiang, Shui-shi

2015-08-01

In this work, two high-performance liquid chromatography (HPLC) assays were developed and validated for the independent determination of edaravone and taurine using 3-methyl-1-p-tolyl-5-pyrazolone and L-glutamine as internal standards. In in vitro experiments, human plasma was separately spiked with a mixture of edaravone and taurine, edaravone or taurine alone. Plasma was precipitated with acetonitrile containing 0.1% formic acid. Ultrafiltration was employed to obtain the unbound ingredients of the two drugs. The factors that might influence the ultrafiltration effiency were elaborately optimized. Plasma supernatant and ultrafiltrate containing taurine were derivated with o-phthalaldehyde and ethanethiol in the presence of 40 mmol/L sodium borate buffer (pH 10.2) at room temperature within 1 min. Chromatographic separations were achieved on an InertSustain C18 column (250 × 4.6 mm, 5 µm). Isocratic 50 mmol/L ammonium acetate-acetonitrile and gradient 50 mmol/L sodium acetate (pH 5.3)-methanol were respectively selected as the mobile phase for the determination of edaravone and taurine. All of the validation data including linearity, extraction recovery, precision, accuracy and stability conformed to the requirements. Results showed that there were no significant alterations in the plasma protein binding rate of taurine and edaravone, implying that the proposed combination therapy was pharmacologically feasible. Copyright © 2014 John Wiley & Sons, Ltd.

Supported mesoporous carbon ultrafiltration membrane and process for making the same

DOEpatents

Strano, Michael; Foley, Henry C.; Agarwal, Hans

2004-04-13

A novel supported mesoporous carbon ultrafiltration membrane and process for producing the same. The membranes comprise a mesoporous carbon layer that exists both within and external to the porous support. A liquid polymer precursor composition comprising both carbonizing and noncarbonizing templating polymers is deposited on the porous metal support. The coated support is then heated in an inert-gas atmosphere to pyrolyze the polymeric precursor and form a mesoporous carbon layer on and within the support. The pore-size of the membranes is dependent on the molecular weight of the noncarbonizing templating polymer precursor. The mesoporous carbon layer is stable and can withstand high temperatures and exposure to organic chemicals. Additionally, the porous metal support provides excellent strength properties. The composite structure of the membrane provides novel structural properties and allows for increased operating pressures allowing for greater membrane flow rates. The invention also relates to the use of the novel ultrafiltration membrane to separate macromolecules from solution. An example is shown separating bovine serum albumin from water. The membrane functions by separating and by selective adsorption. Because of the membrane's porous metal support, it is well suited to industrial applications. The unique properties of the supported mesoporous carbon membrane also allow the membrane to be used in transient pressure or temperature swing separations processes. Such processes were not previously possible with existing mesoporous membranes. The present invention, however, possesses the requisite physical properties to perform such novel ultrafiltration processes.

Improved antifouling performance of ultrafiltration membrane via preparing novel zwitterionic polyimide

NASA Astrophysics Data System (ADS)

Huang, Haitao; Yu, Jiayu; Guo, Hanxiang; Shen, Yibo; Yang, Fan; Wang, Han; Liu, Rong; Liu, Yang

2018-01-01

On the basis of the outstanding fouling resistance of zwitterionic polymers, an antifouling ultrafiltration membrane was fabricated through phase inversion induced by immersion precipitation method, directly using the novel zwitterionic polyimide (Z-PI), which was synthesized via a two-step procedure including polycondensation and quaternary amination reaction, as membrane material. The chemical structure and composition of the obtained polymer were confirmed by using FTIR, 1H NMR and XPS analysis, and its thermal stability was thoroughly characterized by TGA measurement, respectively. The introduction of zwitterionic groups into polyimide could effectively increase membrane pore size, porosity and wettability, and convert the membrane surface from hydrophobic to highly hydrophilic. As a result, Z-PI membrane displayed significantly improved water permeability compared with that of the reference polyimide (R-PI) membrane without having an obvious compromise in protein rejection. According to the static adsorption and dynamic cycle ultrafiltration experiments of bovine serum albumin (BSA) solution, Z-PI membrane exhibited better fouling resistant ability, especially irreversible fouling resistant ability, suggesting superior antifouling property and long-term performance stability. Moreover, Z-PI membrane had a water flux recovery ratio of 93.7% after three cycle of BSA solution filtration, whereas only about 68.5% was obtained for the control R-PI membrane. These findings demonstrated the advantages of Z-PI membrane material and aimed to provide a facile and scalable method for the large-scale preparation of low fouling ultrafiltration membranes for potential applications.

Continuous enzymatic hydrolysis of lignocellulosic biomass in a membrane-reactor system: Continuous enzymatic hydrolysis of lignocellulosic biomass in a membrane-reactor system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stickel, Jonathan J.; Adhikari, Birendra; Sievers, David A.

Converting abundant lignocellulosic biomass to sugars as fungible precursors to fuels and chemicals has the potential to diversify the supply chain for those products, but further process improvements are needed to achieve economic viability. In the current work, process intensification of the key enzymatic hydrolysis unit operation is demonstrated by means of a membrane reactor system that was operated continuously. Lignocellulosic biomass (pretreated corn stover) and buffered enzyme solution were fed to a continuously stirred-tank reactor, and clarified sugar solution was withdrawn via a commercial tubular ultrafiltration membrane. The membrane permeance decline and membrane cleaning efficacy were studied and didmore » not vary significantly when increasing fraction insoluble solids (FIS) from 2.5% to 5%. Continuous enzymatic hydrolysis was successfully operated for more than 80 h. A model for the reactor system was able to predict dynamic behavior that was in reasonable agreement with experimental results. The modeled technical performance of anticipated commercial batch and continuous enzymatic hydrolysis processes were compared and showed that continuous operation would provide at least twice the volumetric productivity for the conditions studied. Further improvements are anticipated by better membrane selection and by increasing FIS.« less

Continuous enzymatic hydrolysis of lignocellulosic biomass in a membrane-reactor system: Continuous enzymatic hydrolysis of lignocellulosic biomass in a membrane-reactor system

DOE PAGES

Stickel, Jonathan J.; Adhikari, Birendra; Sievers, David A.; ...

2018-02-21

Converting abundant lignocellulosic biomass to sugars as fungible precursors to fuels and chemicals has the potential to diversify the supply chain for those products, but further process improvements are needed to achieve economic viability. In the current work, process intensification of the key enzymatic hydrolysis unit operation is demonstrated by means of a membrane reactor system that was operated continuously. Lignocellulosic biomass (pretreated corn stover) and buffered enzyme solution were fed to a continuously stirred-tank reactor, and clarified sugar solution was withdrawn via a commercial tubular ultrafiltration membrane. The membrane permeance decline and membrane cleaning efficacy were studied and didmore » not vary significantly when increasing fraction insoluble solids (FIS) from 2.5% to 5%. Continuous enzymatic hydrolysis was successfully operated for more than 80 h. A model for the reactor system was able to predict dynamic behavior that was in reasonable agreement with experimental results. The modeled technical performance of anticipated commercial batch and continuous enzymatic hydrolysis processes were compared and showed that continuous operation would provide at least twice the volumetric productivity for the conditions studied. Further improvements are anticipated by better membrane selection and by increasing FIS.« less

NE Won't Return to Pre-Recession Employment until 2015, but Region's "Education" Advantage Could Offer "Economic" Advantage

ERIC Educational Resources Information Center

Gittell, Ross

2012-01-01

The New England states continue to experience slow growth and slow recovery of the jobs lost in the 2008 to 2009 recession. The main reason for this is the continued weakness in global and U.S. economic conditions. The U.S. and New England economies continue to be affected by the weak European economy and sovereign debt crisis and by weakness in…

Ceramic membrane ultrafiltration of natural surface water with ultrasound enhanced backwashing.

PubMed

Boley, A; Narasimhan, K; Kieninger, M; Müller, W-R

2010-01-01

Ultrafiltration membrane cleaning with ultrasound enhanced backwashing was investigated with two ceramic membrane systems in parallel. One of them was subjected to ultrasound during backwashing, the other acted as a reference system. The feed water was directly taken from a creek with a sedimentation process as only pre-treatment. The cleaning performance was improved with ultrasound but after 3 weeks of operation damages occurred on the membranes. These effects were studied with online measurements of flux, trans-membrane-pressure and temperature, but also with integrity tests, turbidity measurements and visual examination.

Comparison of colorimetry and electrothermal atomic absorption spectroscopy for the quantification of non-transferrin bound iron in human sera.

PubMed

Jittangprasert, Piyada; Wilairat, Prapin; Pootrakul, Pensri

2004-12-01

This paper describes a comparison of two analytical techniques, one employing bathophenanthrolinedisulfonate (BPT), a most commonly-used reagent for Fe (II) determination, as chromogen and an electrothermal atomic absorption spectroscopy (ETAAS) for the quantification of non-transferrin bound iron (NTBI) in sera from thalassemic patients. Nitrilotriacetic acid (NTA) was employed as the ligand for binding iron from low molecular weight iron complexes present in the serum but without removing iron from the transferrin protein. After ultrafiltration the Fe (III)-NTA complex was then quantified by both methods. Kinetic study of the rate of the Fe (II)-BPT complex formation for various excess amounts of NTA ligand was also carried out. The kinetic data show that a minimum time duration (> 60 minutes) is necessary for complete complex formation when large excess of NTA is used. Calibration curves given by colorimetric and ETAAS methods were linear over the range of 0.15-20 microM iron (III). The colorimetric and ETAAS methods exhibited detection limit (3sigma) of 0.13 and 0.14 microM, respectively. The NTBI concentrations from 55 thalassemic serum samples measured employing BPT as chromogen were statistically compared with the results determined by ETAAS. No significant disagreement at 95% confidence level was observed. It is, therefore, possible to select any one of these two techniques for determination of NTBI in serum samples of thalassemic patients. However, the colorimetric procedure requires a longer analysis time because of a slow rate of exchange of NTA ligand with BPT, leading to the slow rate of formation of the colored complex.

Fabrication of a porous material with a porosity gradient by a pulsed electric current sintering process

NASA Astrophysics Data System (ADS)

Suk, Myung-Jin; Choi, Sung-II; Kim, Ji-Soon; Kim, Young Do; Kwon, Young-Soon

2003-12-01

A porous structure with a porosity gradient can be applied to the preparation of continuous FGM, where liquid or chemical vapor of the second phase is infiltrated into the graded pores. It also has applications in skeletal implant materials and ultrafiltration media. An attempt was made to fabricate a porous material with a porosity gradient by means of a pulsed electric current sintering (PECS) process. The present work describes not only the measured value of the temperature difference between the upper and lower part of the specimen, which brings about a gradual change in pore distribution, but also the sintering characteristics of the porous structure obtained by the pressureless PECS process.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azhar, A.; Hamdy, M.K.

Use of ultrafiltration membrane systems in stirred cell and in thin-channel systems for immobilizing enzyme (sweet potato intrinsic and crystalline beta-amylase) in hydrolysis of sweet potato through a continuous operation mode were studied. Both the filtration rate and reducing sugars, produced as the result of enzymic hydrolysis, decreased with the filtration time. The immobilized enzymes in the thin-channel system showed a much better performance compared to that in the stirred cell system. Addition of crystalline sweet potato beta-amylase to the sweet potato increased both the filtration rate and reducing-sugars content. Alcohol fermentation of the filtrate resulted in an alcohol contentmore » of 4.2%. This represented fermentation of 95% of the sugars with an efficiency of 88%.« less

Evaluation of solute penetration across the polysulfone membrane with vitamin E coating.

PubMed

Yamashita, Akihiro C; Masaki, Hidenori; Kobayashi, Eisuke; Sukegawa, Takeshi

2015-10-01

Vitamin E (vit E) is coated on polysulfone (PS) dialysis membrane for antioxidative purpose. The membrane, however, has not yet been evaluated from the mass transfer point of view. We investigated this PS membrane with and without vit E coating in vitro ultrafiltration experiments to identify whether or not the coating influences the mass transfer. Dialyzers that included PS membrane with and without vit E coating were investigated. Aqueous test solution of various solutes including vitamin B12 (VB12 , MW1355), chymotrypsin (chymo, MW25000), and albumin (alb, MW66000) was prepared, and normal ultrafiltration experiments were performed at 310 K. Reverse ultrafiltration experiments in which test solution was filtered from outside to inside the hollow fiber were also performed. Sieving coefficients (SC) were computed for evaluation. SC for VB12 was the same regardless of vit E coating; however, chymo was 0.82 ± 0.01 and 0.86 ± 0.01, respectively, for the membrane with and without vit E. Thus, it would be understood that vit E coating reduces the pore size of the membrane, resulting the reduced transport of larger solutes. Like other PS membrane, SC for alb was decreased over time regardless of vit E coating. More importantly, although the steady-state SC for alb was almost identical in two membranes, PS without vit E showed much greater decrease for the first 2 h, while that with vit E showed very little decrease over time, which suggested the reduced fouling effect due to vit E coating. All the SC values found in reverse ultrafiltration were higher than those found in normal ultrafiltration; moreover, the degree of increase with chymo was approximately 5%, whereas that with alb was approximately 430%, which may be explained by a new model in which wedge effect is taken into consideration for the membrane transport. Vit E coating not only has antioxidative effect but also reduces the fouling that is usually caused by various proteins. © 2015 International Society for Hemodialysis.

PEP Support Laboratory Leaching and Permeate Stability Tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russell, Renee L.; Peterson, Reid A.; Rinehart, Donald E.

2009-09-25

Pacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). The Pretreatment Engineering Platform (PEP) was designed, constructed, and operated as part of a plan to respond to issue M12, "Undemonstrated Leaching Processes," of the External Flowsheet Review Team (EFRT) issue response plan.( ) The PEP is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, and slurry washing processes.more » The PEP replicates the WTP leaching processes using prototypic equipment and control strategies. A simplified flow diagram of the PEP system is shown in Figure 1.1. Two operating scenarios are currently being evaluated for the ultrafiltration process (UFP) and leaching operations. The first scenario has caustic leaching performed in the UFP-2 ultrafiltration feed vessels (i.e., vessel UFP-VSL-T02A in the PEP and vessels UFP-VSL-00002A and B in the WTP PTF). The second scenario has caustic leaching conducted in the UFP-1 ultrafiltration feed preparation vessels (i.e., vessels UFP-VSL-T01A and B in the PEP and vessels UFP-VSL-00001A and B in the WTP PTF). In both scenarios, 19-M sodium hydroxide solution (NaOH, caustic) is added to the waste slurry in the vessels to leach solid aluminum compounds (e.g., gibbsite, boehmite). Caustic addition is followed by a heating step that uses direct injection of steam to accelerate the leach process. Following the caustic leach, the vessel contents are cooled using vessel cooling jackets and/or external heat exchangers. The main difference between the two scenarios is that for leaching in UFP-VSL-T01A and B, the 19-M NaOH is added to un-concentrated waste slurry (3 to 8 wt% solids), while for leaching in UFP-VSL-T02A, the slurry is concentrated to nominally 20 wt% solids using cross-flow ultrafiltration before adding caustic.« less

Efficient removal of nickel(II) from high salinity wastewater by a novel PAA/ZIF-8/PVDF hybrid ultrafiltration membrane.

PubMed

Li, Ting; Zhang, Weiming; Zhai, Shu; Gao, Guandao; Ding, Jie; Zhang, Wenbin; Liu, Yang; Zhao, Xin; Pan, Bingcai; Lv, Lu

2018-06-15

The development of highly efficient membranes, especially those aimed at the removal of trace (ppm, 10 -6 ) heavy metals from high salinity wastewater, is one of the principal challenges in the wastewater treatment field. In this study, a new metal-organic frameworks-based hybrid ultrafiltration membrane (PAA/ZIF-8/PVDF membrane) was prepared, which outperformed some other adsorption materials and owned the first and highest reported nickel ion (Ni(II)) adsorption capacity (219.09 mg/g) in high salinity ([Na + ] = 15000 mg/L) wastewater. Novel and highly efficient hybrid ultrafiltration membrane was facilely fabricated by physically immobilizing zeolitic imidazolate framework-8 (ZIF-8) particles onto the surface of trimesoyl chloride (TMC)-modified polyvinylidene fluoride (PVDF) membrane under the protection of polyacrylic acid (PAA) layer, and possessed a relatively high water flux of ∼460 L m -2 h -1 . The XPS studies revealed that the Ni(II) uptake was mainly attributed to the specific hydrogen bonding interaction between Ni(II) and hydroxyl on ZIF-8 frameworks as well as the electrostatic adsorption by carboxyl groups in PAA layer. Especially, compared to PAA, ZIF-8 could selectively bind with Ni(II) effectively, which was almost not affected by concentrated sodium ion. The filtration study showed that the membrane with an area of 12.56 cm 2 could treat 5.76 L of Ni(II)-contained high salinity wastewater ([Ni(II) = 2 mg/L, [Na + ] = 15000 mg/L) to meet the maximum contaminant level of 0.1 mg/L Ni(II). Moreover, the hybrid membrane can be regenerated several times by HCl-NaCl solution (pH = 5.5) for repeated use under direct current electric field. Thus, the newly developed ZIF-8 hybrid ultrafiltration membrane showed a promising potential for heavy metals containing wastewater treatment. This work provides a worthy reference for designing highly efficient ultrafiltration membranes modified by metal-organic frameworks. Copyright © 2018 Elsevier Ltd. All rights reserved.

Concentration of infectious aquatic rhabdoviruses from freshwater and seawater using ultrafiltration.

PubMed

Grant, Amelia A M; Jakob, Eva; Richard, Jon; Garver, Kyle A

2011-12-01

Infectious hematopoietic necrosis virus (IHNV), viral hemorrhagic septicemia virus, and spring viremia of carp virus were concentrated and detected from freshwater and seawater samples by using hollow-fiber ultrafiltration. Within 60 min, virus in a 50-L freshwater or saltwater sample was concentrated more than 70-fold, and virus retention efficiencies were consistently greater than 88%. Retention efficiency was highly dependent upon concentrations of column blocking and sample stabilization solutions. A large column with a surface area of 1.15 m2 and a filtration capacity of 5-200 L exhibited optimal viral retention when blocked with 2% fetal bovine serum (FBS) and when the samples were supplemented with 0.1% FBS. Conversely, a small column with 100-fold less surface area and a filtering capacity of 0.5-2.0 L was optimized when blocked with 1% FBS and when the samples were supplemented with 0.1% FBS. The optimized ultrafiltration procedure was further validated with water from a tank that contained IHNV-exposed juvenile sockeye salmon Oncorhynchus nerka, resulting in an average virus retention efficiency of 91.6 +/- 4.1% (mean +/- SE). Virus quantification of concentrated samples demonstrated that IHNV shedding in sockeye salmon preceded mortality; shedding of the virus was observed to increase significantly as early as 7 d postchallenge and peaked at day 14, when virus levels reached 4.87 x 10(3) plaque-forming units/mL. We conclude that ultrafiltration is a reliable and effective method for concentrating viable aquatic rhabdoviruses from large volumes of water and has application for the analysis of environmental water samples.

Xanthan gum recovery from fermentation broth using ultrafiltration: Kinetics and process evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lo, Y.M.; Yang, S.T.; Min, D.B.

1995-12-01

Ultrafiltration of xanthan gum solution as an alternative method to alcohol precipitation for xanthan gum recovery from dilute fermentation broth was studied. A polysulfone membrane (with 500,000 MWCO) hollow fiber (106 mil fiber diameter) tubular cartridge was used to concentrate xanthan broth from less than 3 (w/v) % to {approximately}13.5 (w/v) %, with the xanthan recovery yield of {approximately}95 % or higher. During ultrafiltration, the filtrate flux was one order of magnitude lower for xanthan broth than for water, However, the flux remained almost constant for xanthan concentrations up to {approximately}8%. It was then reduced dramatically as the xanthan concentrationmore » increased beyond 8%. The reduced filtrate flux was caused by the reduced pumping (shear) rate and higher viscosities at higher xanthan concentrations. At constant xanthan concentration, the filtrate flux remained almost unchanged for the entire period studied, suggesting that the process is not subject to membrane fouling. In general, the filtrate flux decreased with increasing the xanthan concentration and increased with increasing the pumping (shear) rate and the trans-membrane pressure difference. Changing the solution pH had a slight effect on the viscosity of xanthan solution, but did not affect the filtration performance. Even under high-shear-rate conditions, ultrafiltration did not give any adverse effects on the rheological properties and molecular weight of the xanthan polymer. Thus, ultra filtration can be used to concentrate xanthan broth from fermentation by a factor of four or higher and to reduce the subsequent alcohol recovery costs by at least 75 %.« less

Acute effects of ultrafiltration on aortic mechanical properties determined by measurement of pulse wave velocity and pulse propagation time in hemodialysis patients

PubMed Central

Yıldız, Banu Şahin; Şahin, Alparslan; Aladağ, Nazire Başkurt; Arslan, Gülgün; Kaptanoğulları, Hakan; Akın, İbrahim; Yıldız, Mustafa

2015-01-01

Objective: The effects of acute hemodialysis session on pulse wave velocity are conflicting. The aim of the current study was to assess the acute effects of ultrafiltration on the aortic mechanical properties using carotid-femoral (aortic) pulse wave velocity and pulse propagation time. Methods: A total of 26 (12 women, 14 men) consecutive patients on maintenance hemodialysis (mean dialysis duration: 40.7±25.6 (4-70) months) and 29 healthy subjects (13 women, 16 men) were included in this study. Baseline blood pressure, carotid-femoral (aortic) pulse wave velocity, and pulse propagation time were measured using a Complior Colson device (Createch Industrie, France) before and immediately after the end of the dialysis session. Results: While systolic blood pressure, diastolic blood pressure, mean blood pressure, pulse pressure, and pulse wave velocity were significantly higher in patients on hemodialysis than in healthy subjects, pulse propagation time was significantly higher in healthy subjects. Although body weight, systolic blood pressure, diastolic blood pressure, mean blood pressure, pulse pressure, and pulse wave velocity were significantly decreased, heart rate and pulse propagation time were significantly increased after ultrafiltration. There was a significant positive correlation between pulse wave velocity and age, body height, waist circumference, systolic blood pressure, diastolic blood pressure, mean blood pressure, pulse pressure, and heart rate. Conclusion: Although hemodialysis treatment may chronically worsen aortic mechanical properties, ultrafiltration during hemodialysis may significantly improve aortic pulse wave velocity, which is inversely related to aortic distensibility and pulse propagation time. PMID:25413228

[Management of patients with chronic renal failure during surgical correction of cardiovascular disease].

PubMed

Iarustovskiĭ, M B; Stupchenko, O S; Abramian, M V; Nazarova, E I; Popok, Z V

2010-01-01

End-stage of chronic renal failure (CRF) is frequently associated with cardiac and vascular comorbidities requiring cardiosurgical interventions. Over 9 years, from 2000 to 2009, the A. N. Bakulev Research Center of Cardiovascular Surgery, Russian Academy of Medical Sciences, delivered cardiosurgical care to 16 patients aged 20 to 74 years with end-stage CRF. The duration of programmed hemodialysis was 1 to 102 months. The preoperative patient preparation protocol comprised correction of anemia, hypoproteinemia, hypertension, and water-electrolyte and acid-base balances. Five patients underwent endovascular myocardial revascularization; open heart surgery was performed in one patient. Interventions under extracorporeal circulation were made in 10 other patients. Ultrafiltration was intraoperatively carried out. On-line hemodiafiltration was performed following coronary artery stenting. After open operations, renal replacement therapy (first hemodiafiltration, then hemodialysis) as daily sessions was initiated on day 2 and, when the patients were transferred to intensive care units, it was performed by the programmed hemodialysis protocol. There were no fatal outcomes at the follow-up. The key aspects of treatment success achievement and improved quality of life in patients on programmed hemodialysis are the detection of cardiovascular diseases requiring surgery, the timely referral of the patients to a cardiosurgical hospital, the meticulous pre- and perioperative management (correction of anemia, hypoproteinemia, water-electrolyte balance, use of ultrafiltration and the adequate rate of perfusion at the stage of extracorporeal circulation, and daily renal replacement therapy in the postoperative period), and continuity in the work of all specialists.

Quantification of autonomic nervous activity by heart rate variability and approximate entropy in high ultrafiltration rate during hemodialysis.

PubMed

Tsuji, Yoshihiro; Suzuki, Naoki; Hitomi, Yasumasa; Yoshida, Toshiko; Mizuno-Matsumoto, Yuko

2017-06-01

Few studies have focused on the imbalance of the autonomic nervous system in ultrafiltration rate (UFR) subjects without blood pressure variation during maintenance hemodialysis (HD), although the role of autonomic nervous system activation during HD has been proposed to be an important factor for the maintenance of blood pressure. Variations over time in autonomic nervous activity due to differences in UFR were evaluated by measuring heart rate variability (HRV) and approximate entropy (ApEn) in 35 HD patients without blood pressure variations during HD session. The subjects were divided into 3 groups, those with UFR <10 ml/h/kg; ≥10 ml/h/kg but ≤15 ml/h/kg; and >15 ml/h/kg, and Holter ECG was recorded continuously during HD session using frequency analysis of RR intervals. High frequency (HF) and low frequency (LF) spectral components are found to be representative of the parasympathetic nervous system and sympathovagal balance, respectively, with the ratio of LF to HF of HRV providing a measure of sympathetic nervous system. In subjects with UFR >15 ml/h/kg, HF components were significantly lower, and LF/HF and ApEn values were significantly higher, in the latter half of an HD session than before starting HD. Removing water from these subjects would promote sustained sympathetic nervous overactivity. These findings indicate that the UFR during HD needs to be set at ≤15 ml/h/kg.

Definitions of differences and changes in peritoneal membrane water transport properties.

PubMed

Widerøe, T E; Smeby, L C; Dahl, K; Jörstad, S

1988-06-01

A survey is given comparing measurements of transperitoneal water transport in different clinical situations with analyses based on the so-called "pore theory." This model links the measured changes to physical alterations of the peritoneal membrane. The calculations include "equivalent pore radius," effective "membrane area" and diffusive length, the transport resistance of the unstirred dialysate layer, and the residual intraperitoneal volume after dialysate drainage. The clinical appearances include individual differences in transperitoneal transport characteristics, changes in transperitoneal transport over time on continuous ambulatory peritoneal dialysis (CAPD) and during peritonitis, the pharmacological effect on the transport properties, and the effect of peritoneal catheter dislocation on ultrafiltration capacity. The main conclusions are as follow: During CAPD treatment the measurement of intraperitoneal solute equilibration and "mass-transfer-area coefficients" for urea and creatinine is less sensitive than the measurement of ultrafiltration volume in revealing peritoneal membrane changes. Differences and changes found have mostly a combined physical explanation, but one is more or less dominant. Changes in peritoneal membrane area seem to be the most dominant cause of changes in transperitoneal transport during time on CAPD and when sodium nitroprusside was added to the peritoneal dialysate. Changes during peritonitis can be explained by changes in pore radius and depth. Individual differences can be explained by differences in "membrane" area and in resistance of the unstirred dialysate fluid. High residual dialysate volume can give rise to clinical problems and should be considered when placing the catheter in the peritoneal cavity.

Antimicrobial compounds of porcine mucosa

NASA Astrophysics Data System (ADS)

Kotenkova, E. A.; Lukinova, E. A.; Fedulova, L. V.

2017-09-01

The aim of the study was to investigate porcine oral cavity mucosa (OCM), nasal cavity mucosa (NCM), rectal mucosa (RM) and tongue mucosa (TM) as sources of antimicrobial compounds. Ultrafiltrates with MW >30 kDa, MW 5-30 kDa and MW <5 kDa were obtained. All ultrafiltrates had antimicrobial activity against Escherichia coli and Proteus vulgaris. NCM ultrafiltrates revealed the highest antibacterial activity in respect to negative control: for the fraction with MW >30 kDa, the zone of microbial growth inhibition was 7.5 mm, for the MW<5 kDa fraction, it was 7 mm, and for MW 5-30 kDa fraction, it was 4.5 mm. No significant differences were found in high molecular weight proteomic profile, while qualitative and quantitative differences were observed in the medium and low molecular weight areas, especially in OCM and NCM. HPLC showed 221 tissue-specific peptides in OCM, 156 in NCM, 225 in RM, but only 5 in TM. The results observed confirmed porcine mucous tissues as a good source of antimicrobial compounds, which could be an actual alternative for reduction of microbial spoilage of foods.

Treatment of laundry wastewater using polyethersulfone/polyvinylpyrollidone ultrafiltration membranes.

PubMed

Sumisha, A; Arthanareeswaran, G; Lukka Thuyavan, Y; Ismail, A F; Chakraborty, S

2015-11-01

In this study, laundry wastewater filtration was studied using hydrophilic polyvinylpyrollidone (PVP) modified polyethersulfone (PES) ultrafiltration membranes. The performances of PES/PVP membranes were assessed using commercial PES membrane with 10kDa in ultrafiltration. Operating parameters The influence of transmembrane pressure (TMP) and stirring speed on laundry wastewater flux was investigated. A higher permeate flux of 55.2L/m(2)h was obtained for modified PES membrane with high concentration of PVP at TMP of 500kPa and 750rpm of stirring speed. The separation efficiencies of membranes were also studied with respect to chemical oxygen demand (COD), total dissolved solids (TDS), turbidity and conductivity. Results showed that PES membrane with 10% of PVP had higher permeate flux, flux recovery and less fouling when compared with other membranes. Higher COD and TDS rejection of 88% and 82% were also observed for modified membranes due to the improved surface property of membranes. This indicated that modified PES membranes are suitable for the treatment of surfactant, detergent and oil from laundry wastewater. Copyright © 2015 Elsevier Inc. All rights reserved.

Preparation and characterization of a novel highly hydrophilic and antifouling polysulfone/nanoporous TiO2 nanocomposite membrane.

PubMed

Bidsorkhi, H Cheraghi; Riazi, H; Emadzadeh, D; Ghanbari, M; Matsuura, T; Lau, W J; Ismail, A F

2016-10-14

In this research, novel ultrafiltration nanocomposite membranes were prepared by incorporating self-synthesized nanoporous titanium dioxide (NTiO2) nanoparticles into polysulfone. The surface of the nanoparticle was treated with a silane-based modifier to improve its distribution in the host polymer. Atomic-force microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller, transmission electron microscopy, energy-dispersive x-ray spectroscopy, porosity and contact angle tests were conducted to characterize the properties of the particles as well as the fabricated nanocomposite membranes. The effects of the nanoparticle incorporation were evaluated by conducting ultrafiltration experiments. It was reported that the membrane pure water flux was increased with increasing NTiO2 loading owing to the high porosity of the nanoparticles embedded and/or formation of enlarged pores upon addition of them. The antifouling capacity of the membranes was also tested by ultrafiltration of bovine serum albumin fouling solution. It was found that both water flux and antifouling capacity tended to reach desired level if the NTiO2 added was at optimized loading.

Differential natural organic matter fouling of ceramic versus polymeric ultrafiltration membranes.

PubMed

Lee, Seung-Jin; Kim, Jae-Hong

2014-01-01

Ceramic ultrafiltration membranes has drawn increasing attention in drinking water treatment sectors as an alternative to traditional polymeric counterparts, yet only limited information has been made available about the characteristics of ceramic membrane fouling by natural organic matter. The effects of solution chemistry including ionic strength, divalent ion concentration and pH on the flux behavior were comparatively evaluated for ceramic and polymeric ultrafiltration of synthetic water containing model natural organic matter. Filtration characteristics were further probed via resistance-in-series model analysis, fouling visualization using quantum dots, batch adsorption test, contact angle measurement, solute-membrane surface adhesion force measurement, and quantitative comparison of fouling characteristics between ceramic and polymeric membranes. The results collectively suggested that the effects of solution chemistry on fouling behavior of ceramic membranes were generally similar to polymeric counterparts in terms of trends, while the extent varied significantly depending on water quality parameters. Lower fouling tendency and enhanced cleaning efficiency were observed with the ceramic membrane, further promoting the potential for ceramic membrane application to surface water treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Efficient Preparation of Super Antifouling PVDF Ultrafiltration Membrane with One Step Fabricated Zwitterionic Surface.

PubMed

Zhao, Xinzhen; He, Chunju

2015-08-19

On the basis of the excellent fouling resistance of zwitterionic materials, the super antifouling polyvinylidene fluoride (PVDF) membrane was efficiently prepared though one-step sulfonation of PVDF and polyaniline blend membrane in situ. The self-doped sulfonated polyaniline (SPANI) was generated as a novel zwitterionic polymer to improve the antifouling property of PVDF ultrafiltration membrane used in sewage treatment. Surface attenuated total reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, surface zeta potential, and water contact angle demonstrated the successful fabrication of zwitterionic interface by convenient sulfonation modification. The static adsorption fouling test showed the quantified adsorption mass of bovine serum albumin (BSA) pollutant on the PVDF/SPANI membrane surface decreases to 3(±2) μg/cm(2), and the water flux recovery ratio (FRR) values were no less than 95% for the three model pollutants of BSA, sodium alginate (SA), and humic acid (HA), which were corresponding hydrophobic, hydrophilic, and natural pollutants in sewage, respectively. This Research Article demonstrated the antifouling advantages of zwitterionic SPANI and aimed to provide a simple method for the large scale preparation of zwitterionic antifouling ultrafiltration membranes.

Influence of pH and temperature of dip-coating solution on the properties of cellulose acetate-ceramic composite membrane for ultrafiltration.

PubMed

Kaur, Harjot; Bulasara, Vijaya Kumar; Gupta, Raj Kumar

2018-09-01

Polymer-ceramic composite membranes were prepared by dip coating technique using 5 wt.% cellulose acetate (CA) solution at different temperatures (15 °C, 25 °C and 40 °C). The effect of pH (2-12) of the polymeric solution on the properties of the membranes was studied using SEM, EDAX, FTIR, gas and liquid permeation. The thickness of the polymeric layer depended on the interaction of CA solution with the surface of ceramic support. Membrane permeability decreased with increase in pH because of decrease in pore size and porosity resulting from strong interaction of the polymer layer with the ceramic support. The porosity and mean pore size of the prepared membranes were found to be 28-60% and 30-47 nm (ultrafiltration range), respectively. The optimized membrane (pH 7) was used for ultrafiltration of oil in water emulsions (100 and 200 mg/L). Oil rejection of 99.61% was obtained for 100 mg/L of oil concentration in water. Copyright © 2018 Elsevier Ltd. All rights reserved.

Graphene oxide based ultrafiltration membranes for photocatalytic degradation of organic pollutants in salty water.

PubMed

Pastrana-Martínez, Luisa M; Morales-Torres, Sergio; Figueiredo, José L; Faria, Joaquim L; Silva, Adrián M T

2015-06-15

Flat sheet ultrafiltration (UF) membranes with photocatalytic properties were prepared with lab-made TiO2 and graphene oxide-TiO2 (GOT), and also with a reference TiO2 photocatalyst from Evonik (P25). These membranes were tested in continuous operation mode for the degradation and mineralization of a pharmaceutical compound, diphenhydramine (DP), and an organic dye, methyl orange (MO), under both near-UV/Vis and visible light irradiation. The effect of NaCl was investigated considering simulated brackish water (NaCl 0.5 g L(-1)) and simulated seawater (NaCl 35 g L(-1)). The results indicated that the membranes prepared with the GOT composite (M-GOT) exhibited the highest photocatalytic activity, outperforming those prepared with bare TiO2 (M-TiO2) and P25 (M-P25), both inactive under visible light illumination. The best performance of M-GOT may be due to the lower band-gap energy (2.9 eV) of GOT. In general, the permeate flux was also higher for M-GOT probably due to a combined effect of its highest photocatalytic activity, highest hydrophilicity (contact angles of 11°, 17° and 18° for M-GOT, M-TiO2 and M-P25, respectively) and higher porosity (71%). The presence of NaCl had a detrimental effect on the efficiency of the membranes, since chloride anions can act as hole and hydroxyl radical scavengers, but it did not affect the catalytic stability of these membranes. A hierarchically ordered membrane was also prepared by intercalating a freestanding GO membrane in the structure of the M-GOT membrane (M-GO/GOT). The results showed considerably higher pollutant removal in darkness and good photocatalytic activity under near-UV/Vis and visible light irradiation in continuous mode experiments. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Effect of Low-GDP Solution on Ultrafiltration and Solute Transport in Continuous Ambulatory Peritoneal Dialysis Patients

PubMed Central

Cho, Kyu-Hyang; Do, Jun-Young; Park, Jong-Won; Yoon, Kyung-Woo; Kim, Yong-Lim

2013-01-01

♦ Background: Several studies have reported benefits for human peritoneal mesothelial cell function of a neutral-pH dialysate low in glucose degradation products (GDPs). However, the effects of low-GDP solution on ultrafiltration (UF), transport of solutes, and control of body water remain elusive. We therefore investigated the effect of low-GDP solution on UF, solute transport, and control of body water. ♦ Methods: Among 79 new continuous ambulatory peritoneal dialysis (CAPD) patients, 60 completed a 12-month protocol (28 in a lactate-based high-GDP solution group, 32 in a lactate-based low-GDP solution group). Clinical indices—including 24-hour UF volume (UFV), 24-hour urine volume (UV), residual renal function, and dialysis adequacy—were measured at months 1, 6, and 12. At months 1, 6, and 12, UFV, glucose absorption, 4-hour dialysate-to-plasma (D/P) creatinine, and 1-hour D/P Na+ were assessed during a modified 4.25% peritoneal equilibration test (PET). Body composition by bioelectric impedance analysis was measured at months 1 and 12 in 26 CAPD patients. ♦ Results: Daily UFV was lower in the low-GDP group. Despite similar solute transport and aquaporin function, the low-GDP group also showed lower UFV and higher glucose absorption during the PET. Factors associated with UFV during the PET were lactate-based high-GDP solution and 1-hour D/P Na+. No differences in volume status and obesity at month 12 were observed, and improvements in hypervolemia were equal in both groups. ♦ Conclusions: Compared with the high-GDP group, the low-GDP group had a lower UFV during a PET and a lower daily UFV during the first year after peritoneal dialysis initiation. Although the low-GDP group had a lower daily UFV, no difficulties in controlling edema were encountered. PMID:23284074

Effect of continuous renal replacement therapy on kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin in patients with septic acute kidney injury

PubMed Central

Shao, Yiming; Fan, Yinqiang; Xie, Yuliu; Yin, Lu; Zhang, Yuanli; Deng, Liehua; Sun, Xiaocong; Shao, Xin; Tan, Xinzhang; He, Junbing; Zhao, Shiman

2017-01-01

Kidney injury molecule-1 (Kim-1) and neutrophil gelatinase-associated lipocalin (NGAL) have been investigated as biomarkers for acute kidney injury (AKI). However, they are seldom investigated in patients with septic AKI treated with continuous renal replacement therapy (CRRT). The aim of the present study was to investigate the therapeutic effectiveness and possible mechanisms of CRRT in septic AKI by observing the changes in Kim-1 and NGAL levels. A group of 38 patients with septic AKI was randomly divided into the conventional drug treatment group (group A) and the CRRT group (group B). All patients were treated with standard antisepsis agents, and group B was additionally submitted to CRRT for 24 h. The levels of Kim-1 and NGAL in serum, urine and the ultrafiltrate of CRRT were measured prior to and at 12, 24, and 48 h after treatment. In group A, urinary Kim-1 (uKim-1) levels at 12, 24 and 48 h were lower than prior to treatment (P<0.05), whereas urinary NGAL (uNGAL) showed no difference among the various time points (P>0.05). In group B, uKim-1 was decreased at 24 and 48 h compared with before treatment (all P<0.05), whereas uNGAL was decreased at 48 h (P<0.05). Serum Kim-1 did not change with time in groups A and B (P>0.05), whereas serum NGAL was increased after treatment in group A (P<0.05) but did not change in group B (P>0.05). Kim-1 and NGAL were not detected in the ultrafiltrate of CRRT. uKim-1 and uNGAL decreased significantly after CRRT, and therefore may be used to reflect the change of renal function during CRRT and to evaluate the therapeutic effectiveness of the method. PMID:28588686

Blood purification in the critically ill patient. Prescription tailored to the indication (including the pediatric patient).

PubMed

Sanchez-Izquierdo Riera, J A; Montoiro Allué, R; Tomasa Irriguible, T; Palencia Herrejón, E; Cota Delgado, F; Pérez Calvo, C

2016-10-01

We maintain a dynamic position on extracorporeal blood purification therapies (EBPT). Continuous therapies are of choice in the hemodynamically unstable patient. We recommend their early introduction in the course of the disease, and starting with a dose of 30-35mL/kg/h. Above all, however, daily re-evaluation is required of the hemodynamic and metabolic situation and water balance of our patients in order to allow dynamic dose adjustment. Some data suggest that continuous EBPT can favorably influence the clinical course of our patients, even in the absence of acute kidney injury. The potential usefulness of hemofiltration at doses higher than the conventional doses (continuous ultrafiltration >50mL/kg/h or pulses of at least 4h a day to more than 100dosesmL/kg/h) for achieving blood purification has also been commented. We review the possible indications of this technique, together with the peculiarities of implementing these therapies in children. Copyright © 2016 Elsevier España, S.L.U. y SEMICYUC. All rights reserved.

Application of ultrafiltration and stable isotopic amendments to field studies of mercury partitioning to filterable carbon in lake water and overland runoff.

PubMed

Babiarz, Christopher L; Hurley, James P; Krabbenhoft, David P; Gilmour, Cynthia; Branfireun, Brian A

2003-03-20

Results from pilot studies on colloidal phase transport of newly deposited mercury in lake water and overland runoff demonstrate that the combination of ultrafiltration, and stable isotope amendment techniques is a viable tool for the study of mercury partitioning to filterable carbon. Ultrafiltration mass balance calculations were generally excellent, averaging 97.3, 96.1 and 99.8% for dissolved organic carbon (DOC), total mercury (Hg(T)), and methylmercury (MeHg), respectively. Sub nanogram per liter quantities of isotope were measurable, and the observed phase distribution from replicate ultrafiltration separations on lake water agreed within 20%. We believe the data presented here are the first published colloidal phase mercury data on lake water and overland runoff from uncontaminated sites. Initial results from pilot-scale lake amendment experiments indicate that the choice of matrix used to dissolve the isotope did not affect the initial phase distribution of the added mercury in the lake. In addition there was anecdotal evidence that native MeHg was either recently produced in the system, or at a minimum, that this 'old' MeHg partitions to the same subset of DOC that binds the amended mercury. Initial results from pilot-scale overland runoff experiments indicate that less than 20% of newly deposited mercury was transported in the filterable fraction (<0.7 microm). There is some indication of colloidal phase enrichment of mercury in runoff compared to the phase distribution of organic carbon, but the mechanism of this enrichment is unclear. The phase distribution of newly deposited mercury can differ from that of organic carbon and native mercury, suggesting that the quality of the carbon (available ligands), not the quantity of carbon, regulates partitioning. Further characterization of DOC is needed to clarify the underlying mechanisms.

Efficient ultrafiltration-based protocol to deplete extracellular vesicles from fetal bovine serum

PubMed Central

Kornilov, Roman; Puhka, Maija; Mannerström, Bettina; Hiidenmaa, Hanna; Peltoniemi, Hilkka; Siljander, Pia; Seppänen-Kaijansinkko, Riitta; Kaur, Sippy

2018-01-01

ABSTRACT Fetal bovine serum (FBS) is the most commonly used supplement in studies involving cell-culture experiments. However, FBS contains large numbers of bovine extracellular vesicles (EVs), which hamper the analyses of secreted EVs from the cell type of preference and, thus, also the downstream analyses. Therefore, a prior elimination of EVs from FBS is crucial. However, the current methods of EV depletion by ultracentrifugation are cumbersome and the commercial alternatives expensive. In this study, our aim was to develop a protocol to completely deplete EVs from FBS, which may have wide applicability in cell-culture applications. We investigated different EV-depleted FBS prepared by our novel ultrafiltration-based protocol, by conventionally used overnight ultracentrifugation, or commercially available depleted FBS, and compared them with regular FBS. All sera were characterized by nanoparticle tracking analysis, electron microscopy, Western blotting and RNA quantification. Next, adipose-tissue mesenchymal stem cells (AT-MSCs) and cancer cells were grown in the media supplemented with the three different EV-depleted FBS and compared with cells grown in regular FBS media to assess the effects on cell proliferation, stress, differentiation and EV production. The novel ultrafiltration-based protocol depleted EVs from FBS clearly more efficiently than ultracentrifugation and commercial methods. Cell proliferation, stress, differentiation and EV production of AT-MSCs and cancer cell lines were similarly maintained in all three EV-depleted FBS media up to 96 h. In summary, our ultrafiltration protocol efficiently depletes EVs, is easy to use and maintains cell growth and metabolism. Since the method is also cost-effective and easy to standardize, it could be used in a wide range of cell-culture applications helping to increase comparability of EV research results between laboratories. PMID:29410778

Carprofen pharmacokinetics in plasma and in control and inflamed canine tissue fluid using in vivo ultrafiltration.

PubMed

Messenger, K M; Wofford, J A; Papich, M G

2016-02-01

Measurement of unbound drug concentrations at their sites of action is necessary for accurate PK/PD modeling. The objective of this study was to determine the unbound concentration of carprofen in canine interstitial fluid (ISF) using in vivo ultrafiltration and to compare pharmacokinetic parameters of free carprofen concentrations between inflamed and control tissue sites. We hypothesized that active concentrations of carprofen would exhibit different dispositions in ISF between inflamed vs. normal tissues. Bilateral ultrafiltration probes were placed subcutaneously in six healthy Beagle dogs 12 h prior to induction of inflammation. Two milliliters of either 2% carrageenan or saline control was injected subcutaneously at each probe site, 12 h prior to intravenous carprofen (4 mg/kg) administration. Plasma and ISF samples were collected at regular intervals for 72 h, and carprofen concentrations were determined using HPLC. Prostaglandin E2 (PGE2 ) concentrations were quantified in ISF using ELISA. Unbound carprofen concentrations were higher in ISF compared with predicted unbound plasma drug concentrations. Concentrations were not significantly higher in inflamed ISF compared with control ISF. Compartmental modeling was used to generate pharmacokinetic parameter estimates, which were not significantly different between sites. Terminal half-life (T½) was longer in the ISF compared with plasma. PGE2 in ISF decreased following administration of carprofen. In vivo ultrafiltration is a reliable method to determine unbound carprofen in ISF, and that disposition of unbound drug into tissue is much higher than predicted from unbound drug concentration in plasma. However, concentrations and pharmacokinetic parameter estimates are not significantly different in inflamed vs. un-inflamed tissues. © 2015 John Wiley & Sons Ltd.

The Effect of Neutral Peritoneal Dialysis Solution with Low Glucose-Degradation-Product on the Fluid Status and Body Composition – A Randomized Control Trial

PubMed Central

Szeto, Cheuk-Chun; Kwan, Bonnie C. H.; Chow, Kai-Ming; Cheng, Phyllis M. S.; Kwong, Vickie W. K.; Choy, Agnes S. M.; Law, Man-Ching; Leung, Chi-Bon; Li, Philip K. T.

2015-01-01

Background Previous studies report conflicting results on the benefit of peritoneal dialysis (PD) patients treated with low glucose degradation product (GDP) solution. The effects of low GDP solution on body fluid status and arterial pulse wave velocity (PWV) have not been studied. Methods We randomly assigned 68 incident PD patients to low GDP (Intervention Group) or conventional solutions (Control Group); 4 dropped off before they received the assigned treatment. Patients were followed for 52 weeks for changes in ultrafiltration, residual renal function, body fluid status and arterial PWV. Result After 52 weeks, Intervention Group had higher overhydration (3.1 ± 2.6 vs 1.9 ± 2.2 L, p = 0.045) and extracellular water volume (17.7 ± 3.9 vs 15.8 ± 3.1 L, p = 0.034) than Control Group. There was no significant difference in PWV between groups. There was no significant difference in residual renal function between the Groups. Intervention Group had lower ultrafiltration volume than Control Group at 4 weeks (0.45 ± .0.61 vs 0.90 ± 0.79 L/day, p = 0.013), but the difference became insignificant at later time points. Intervention Group had lower serum CRP levels than Control Group (4.17 ± 0.77 vs 4.91 ± 0.95 mg/dL, p < 0.0001). Conclusion Incident PD patients treated with low GDP solution have less severe systemic inflammation but trends of less ultrafiltration, and more fluid accumulation. However, the effects on ultrafiltration and fluid accumulation disappear with time. The long term effect of low GDP solution requires further study. Trial Registration ClinicalTrials.gov NCT00966615 PMID:26510186

Centrifugal ultrafiltration of human serum for improving immunoglobulin A quantification using attenuated total reflectance infrared spectroscopy.

PubMed

Elsohaby, Ibrahim; McClure, J Trenton; Riley, Christopher B; Bryanton, Janet; Bigsby, Kathryn; Shaw, R Anthony

2018-02-20

Attenuated total reflectance infrared (ATR-IR) spectroscopy is a simple, rapid and cost-effective method for the analysis of serum. However, the complex nature of serum remains a limiting factor to the reliability of this method. We investigated the benefits of coupling the centrifugal ultrafiltration with ATR-IR spectroscopy for quantification of human serum IgA concentration. Human serum samples (n = 196) were analyzed for IgA using an immunoturbidimetric assay. ATR-IR spectra were acquired for whole serum samples and for the retentate (residue) reconstituted with saline following 300 kDa centrifugal ultrafiltration. IR-based analytical methods were developed for each of the two spectroscopic datasets, and the accuracy of each of the two methods compared. Analytical methods were based upon partial least squares regression (PLSR) calibration models - one with 5-PLS factors (for whole serum) and the second with 9-PLS factors (for the reconstituted retentate). Comparison of the two sets of IR-based analytical results to reference IgA values revealed improvements in the Pearson correlation coefficient (from 0.66 to 0.76), and the root mean squared error of prediction in IR-based IgA concentrations (from 102 to 79 mg/dL) for the ultrafiltration retentate-based method as compared to the method built upon whole serum spectra. Depleting human serum low molecular weight proteins using a 300 kDa centrifugal filter thus enhances the accuracy IgA quantification by ATR-IR spectroscopy. Further evaluation and optimization of this general approach may ultimately lead to routine analysis of a range of high molecular-weight analytical targets that are otherwise unsuitable for IR-based analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Ultrasonic control of ceramic membrane fouling by particles: effect of ultrasonic factors.

PubMed

Chen, Dong; Weavers, Linda K; Walker, Harold W

2006-07-01

Ultrasound at 20 kHz was applied to a cross-flow ultrafiltration system with gamma-alumina membranes in the presence of colloidal silica particles to systematically investigate how ultrasonic factors affect membrane cleaning. Based on imaging of the ultrasonic cavitation region, optimal cleaning occurred when the membrane was outside but close to the cavitation region. Increasing the filtration pressure increased the compressive forces driving cavitation collapse and resulted in fewer cavitation bubbles absorbing and scattering sound waves and increasing sound wave penetration. However, an increased filtration pressure also resulted in greater permeation drag, and subsequently less improvement in permeate flux compared to low filtration pressure. Finally, pulsed ultrasound with short pulse intervals resulted in permeate flux improvement close to that of continuous sonication.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azhar, A.; Hamdy, M.K.

Use of ultrafiltration membrane systems in stirred cell and in thin-channel systems for immobilizing enzyme (sweet potato intrinsic and crystalline /beta/-amylase) in hydrolysis of sweet potato through a continuous operation mode were studied. Both the filtration rate and reducing sugars, produced as the result of enzymatic hydrolysis, decreased with the filtration time. THe immobilized enzymes in the thin-channel system showed a much better performance compared to that in the stirred cell system. Addition of crystalline sweet potato /beta/-amylase to the sweet potato increased both the filtration rate and reducing-sugars content. Alcoholic fermentation of the filtrate resulted in an alcohol contentmore » of 4.2%. This represented fermentation of 95% of the sugars with an efficiency of 88%. 17 refs.« less

Simple, high-yield purification of xanthine oxidase from bovine milk.

PubMed

Ozer, N; Müftüoglu, M; Ataman, D; Ercan, A; Ogüs, I H

1999-05-13

Xanthine oxidase, a commercially important enzyme with a wide area of application, was extracted from fresh milk, without added preservatives, using toluene and heat. The short purification procedure, with high yield, consisted of extraction, ammonium sulfate fractionation, and DEAE-Sepharose (fast flow) column chromatography. Xanthine oxidase was eluted as a single activity peak from the column using a buffer gradient. The purification fold, specific activity and yield for the purified xanthine oxidase were 328, 10.161 U/mg and 69%, respectively. The enzyme was concentrated by ultrafiltration, although 31% of the activity was lost during concentration, no change in specific activity was observed. Activity and protein gave coincident staining bands on native polyacrylamide gels. The intensity and the number of bands were dependent on the oxidative state(s) of the enzyme; reduction by 2-mercaptoethanol decreased the intensity of the slow-moving bands and increased the intensity of the fastest-moving band. Following sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), two major bands (molecular masses of 152 and 131 kDa) were observed, accounting for > or = 95% of xanthine oxidase. Native- and SDS-PAGE showed that the purified xanthine oxidase becomes a heterodimer due to endogenous proteases.

The U.S. Economy to 2006. Employment Outlook: 1996-2006.

ERIC Educational Resources Information Center

Boustead, Thomas

1997-01-01

Slowing gross domestic product (GDP) growth is tied to slowing labor force growth; exports and imports continue to be the fastest growing components of GDP, with high technology products leading the way. (Author)

Serum and plasma for total and free anticonvulsant drug analyses: effects on EMIT assays and ultrafiltration devices.

PubMed

Godolphin, W; Trepanier, J; Farrell, K

1983-01-01

The suitability of serum and plasma anticoagulated with heparin, EDTA, citrate, or oxalate was assessed for analysis of free and total phenytoin, carbamazepine, and valproic acid. The free fraction was isolated by ultrafiltration through FreeLevel devices (Syva, Palo Alto, CA). Serum, heparin, and EDTA plasma were satisfactory for both free and total phenytoin and carbamazepine. EDTA could not be used for EMIT (Syva) analysis of valproate. Citrate and, to a lesser degree, oxalate cause a significant negative interference in the concentration of these three drugs as measured both by EMIT and gas-liquid chromatography.

Enrichment and Purification of Casein Glycomacropeptide from Whey Protein Isolate Using Supercritical Carbon Dioxide Processing and Membrane Ultrafiltration

PubMed Central

Bonnaillie, Laetitia M.; Qi, Phoebe; Wickham, Edward; Tomasula, Peggy M.

2014-01-01

Whey protein concentrates (WPC) and isolates (WPI), comprised mainly of β-lactoglobulin (β-LG), α-lactalbumin (α-LA) and casein glycomacropeptide (GMP), are added to foods to boost nutritional and functional properties. Supercritical carbon dioxide (SCO2) has been shown to effectively fractionate WPC and WPI to obtain enriched fractions of α-LA and β-LG, thus creating new whey ingredients that exploit the properties of the individual component proteins. In this study, we used SCO2 to further fractionate WPI via acid precipitation of α-LA, β-LG and the minor whey proteins to obtain GMP-enriched solutions. The process was optimized and α-LA precipitation maximized at low pH and a temperature (T) ≥65 °C, where β-LG with 84% purity and GMP with 58% purity were obtained, after ultrafiltration and diafiltration to separate β-LG from the GMP solution. At 70 °C, β-LG also precipitated with α-LA, leaving a GMP-rich solution with up to 94% purity after ultrafiltration. The different protein fractions produced with the SCO2 process will permit the design of new foods and beverages to target specific nutritional needs. PMID:28234306

The mechanism of the increase in glomerular filtration rate in the twelve-day pregnant rat.

PubMed Central

Baylis, C

1980-01-01

1. Whole kidney and micropuncture techniques were employed to investigate the determinants of glomerular ultrafiltration in virgin and 12-day pregnant rats. 2. A significant increase in whole kidney glomerular filtration rate (g.f.r.) and superficial cortical single nephron g.f.r. was noted in pregnant rats compared to virgins. 3. Increases in whole kidney and glomerular plasma flow rate also occurred in pregnancy which were in proportion to the increase in rate of filtration. No differences were noted in the hydrostatic and oncotic pressures which influence formation of glomerular ultrafiltrate in the superficial nephron population. 4. Reduction in arterial haematocrit and no change in mean red cell volume indicate that a plasma volume expansion has occurred by day 12 of pregnancy in the rat. 5. It is concluded that the increased g.f.r. seen in 12-day pregnant rats is exclusively the result of an increase in renal plasma flow rate (r.p.f.) since the other determinants of glomerular ultrafiltration are unaffected by pregnancy. The plasma volume expansion which also occurs must be, at least in part, responsible for the increase in r.p.f. PMID:7441561

Stabilization of flux during dead-end ultra-low pressure ultrafiltration.

PubMed

Peter-Varbanets, Maryna; Hammes, Frederik; Vital, Marius; Pronk, Wouter

2010-06-01

Gravity driven ultrafiltration was operated in dead-end mode without any flushing or cleaning. In contrary to general expectations, the flux value stabilized after about one week of operation and remained constant during an extended period of time (several months). Different surface water types and diluted wastewater were used as feed water and, depending on the feed water composition, stable flux values were in the range of 4-10 L h(-1) m(-2). When sodium azide was added to the feed water to diminish the biological activity, no stabilization of flux occurred, indicating that biological processes play an important role in the flux stabilization process. Confocal laser scanning microscopy revealed the presence of a biofouling layer, of which the structure changed over time, leading to relatively heterogeneous structures. It is assumed that the stabilization of flux is related to the development of heterogeneous structures in the fouling layer, due to biological processes in the layer. The phenomenon of flux stabilization opens interesting possibilities for application, for instance in simple and low-cost ultrafiltration systems for decentralized drinking water treatment in developing and transition countries, independent of energy supply, chemicals, or complex process control. 2010 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Josephson, Gary B.; Geeting, John GH; Bredt, Ofelia P.

Pacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Waste Treatment Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). The Pretreatment Engineering Platform (PEP) was designed, constructed, and operated as part of a plan to respond to issue M12, "Undemonstrated Leaching Processes." The PEP is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, and slurry washing processes. The PEP replicates the WTP leaching processes using prototypic equipment and control strategies. The PEPmore » also includes non-prototypic ancillary equipment to support the core processing. Two operating scenarios are currently being evaluated for the ultrafiltration process (UFP) and leaching operations. The first scenario has caustic leaching performed in the UFP-2 ultrafiltration feed vessels (i.e., vessel UFP-VSL-T02A in the PEP; and vessels UFP-VSL-00002A and B in the WTP PTF). The second scenario has caustic leaching conducted in the UFP-1 ultrafiltration feed preparation vessels (i.e., vessels UFP-VSL-T01A and B in the PEP; vessels UFP-VSL-00001A and B in the WTP PTF). In both scenarios, 19-M sodium hydroxide solution (NaOH, caustic) is added to the waste slurry in the vessels to leach solid aluminum compounds (e.g., gibbsite, boehmite). Caustic addition is followed by a heating step that uses direct injection of steam to accelerate the leach process. Following the caustic leach, the vessel contents are cooled using vessel cooling jackets and/or external heat exchangers. The main difference between the two scenarios is that for leaching in UFP-1, the 19-M NaOH is added to un-concentrated waste slurry (3-8 wt% solids), while for leaching in UFP-2, the slurry is concentrated to nominally 20 wt% solids using cross-flow ultrafiltration before the addition of caustic. In both scenarios, following the caustic leach, the slurry was then concentrated to 17 wt% and washed with inhibited water to remove NaOH and other soluble salts. Next, the slurry was oxidatively leached using sodium permanganate to solubilize chrome. The slurry was then washed to remove the dissolved chrome and concentrated.« less

A Zeeman slower for diatomic molecules

NASA Astrophysics Data System (ADS)

Petzold, M.; Kaebert, P.; Gersema, P.; Siercke, M.; Ospelkaus, S.

2018-04-01

We present a novel slowing scheme for beams of laser-coolable diatomic molecules reminiscent of Zeeman slowing of atomic beams. The scheme results in efficient compression of the one-dimensional velocity distribution to velocities trappable by magnetic or magneto-optical traps. We experimentally demonstrate our method in an atomic testbed and show an enhancement of flux below v = 35 m s‑1 by a factor of ≈20 compared to white light slowing. 3D Monte Carlo simulations performed to model the experiment show excellent agreement. We apply the same simulations to the prototype molecule 88Sr19F and expect 15% of the initial flux to be continuously compressed in a narrow velocity window at around 10 m s‑1. This is the first experimentally shown continuous and dissipative slowing technique in molecule-like level structures, promising to provide the missing link for the preparation of large ultracold molecular ensembles.

Characterizing Slow Slip Applying Machine Learning

NASA Astrophysics Data System (ADS)

Hulbert, C.; Rouet-Leduc, B.; Bolton, D. C.; Ren, C. X.; Marone, C.; Johnson, P. A.

2017-12-01

Over the last two decades it has become apparent from strain and GPS measurements, that slow slip on earthquake faults is a widespread phenomenon. Slow slip is also inferred from small amplitude seismic signals known as tremor and low frequency earthquakes (LFE's) and has been reproduced in laboratory studies, providing useful physical insight into the frictional properties associated with the behavior. From such laboratory studies we ask whether we can obtain quantitative information regarding the physics of friction from only the recorded continuous acoustical data originating from the fault zone. We show that by applying machine learning to the acoustical signal, we can infer upcoming slow slip failure initiation as well as the slip termination, and that we can also infer the magnitudes by a second machine learning procedure based on predicted inter-event times. We speculate that by applying this or other machine learning approaches to continuous seismic data, new information regarding the physics of faulting could be obtained.

Performance of an ultrafiltration membrane bioreactor (UF-MBR) as a processing strategy for the synthesis of galacto-oligosaccharides at high substrate concentrations.

PubMed

Córdova, Andrés; Astudillo, Carolina; Vera, Carlos; Guerrero, Cecilia; Illanes, Andrés

2016-04-10

The performance of an ultrafiltration membrane bioreactor for galacto-oligosaccharides (GOS) synthesis using high lactose concentrations (470 g/L) and β-galactosidase from Aspergillus oryzae was assessed. Tested processing variables were: transmembrane-pressure (PT), crossflow-velocity (CFV) and temperature. Results showed that processing variables had significant effect on the yield, the enzyme productivity and the flux but did not on GOS concentration and reaction conversion obtained. As expected, the use of high turbulences improved mass transfer and reduced the membrane fouling, but the use of very high crossflow-velocities caused operational instability due to vortex formation and lactose precipitation. The use of a desirability function allowed determining optimal conditions which were: PT (4.38 bar), CFV (7.35 m/s) and temperature (53.1 °C), optimizing simultaneously flux and specific enzyme productivity Under these optimal processing conditions, shear-stress and temperature did not affect the enzyme but long-term operation was limited by flux decay. In comparison to a conventional batch system, at 12.5h of processing time, the continuous GOS synthesis in the UF-MBR increased significantly the amount of processed substrate and a 2.44-fold increase in the amount of GOS produced per unit mass of catalyst was obtained with respect to a conventional batch system. Furthermore, these results can be improved by far by tuning the membranearea/reactionvolume ratio, showing that the use of an UF-MBR is an attractive alternative for the GOS synthesis at very high lactose concentrations. Copyright © 2016 Elsevier B.V. All rights reserved.

Hypoalbuminemia is an important risk factor of hypotension during hemodialysis.

PubMed

Nakamoto, Hidetomo; Honda, Nobuko; Mimura, Taku; Suzuki, Hiromichi

2006-10-01

Hypotension during hemodialysis (HD) is an important problem in patients on HD. To investigate the risk factors that contribute to the hypotension during HD, we compared background factors of hypotensive (HP) patients during HD. Among 58 patients undergoing HD in Tamura Memorial Hospital, 12 patients could not continue full HD because of hypotension. We compared the data of ultrafiltration volume, cardiothoracic ratio (CTR), total protein (TP), serum albumin, blood urea nitrogen (BUN), serum creatinine, total cholesterol (TC), hemoglobin (Hb), blood glucose (BS), brain natriuretic peptide (BNP), and cardiac function between HP patients (HP group; n=12) and sex- and age-matched control patients (NP group; n=12). There were no significant differences of age, sex, and duration of HD between the 2 groups. Cardiothoracic ratio is bigger and BNP is higher in the HP group compared with the NP group (CTR: HP 55.8+/-2.9% vs. NP 47.7+/-1.1%, p=0.0165; BNP: HP 602+/-171 vs. NP 147+/-38, p=0.0167). Serum albumin in the HP group is significantly lower compared with the NP group (HP 3.2+/-0.1 g/dL vs. NP 3.5+/-0.1 g/dL, p=0.0130). However, there were no significant differences of ultrafiltration rate (UFR), BS, TC, Hb, and cardiac function between the 2 groups. There is a significant negative correlation between changes of systolic blood pressure (delta systolic blood pressure) and serum albumin in these patients (r=-0.598, p=0.0016). From these data, we conclude that hypoalbuminemia is a major risk factor of hypotension during HD.

Arsenic removal from water by coupling photocatalysis and complexation-ultrafiltration processes: A preliminary study.

PubMed

Molinari, R; Argurio, P

2017-02-01

Inorganic As removal from contaminated water has been studied by off-line coupling of photocatalysis and complexation-ultrafiltration (CP-UF), showing that this combination permits to obtain a quite complete arsenic removal from the treated water. Two commercial polymers, poly(dimethylamine-coepichlorohydrin-coethylenediamine) (PDEHED) and poly(diallyl dimethyl amnmonium chloride) (PolyDADMAC) have been tested in the CP-UF process. The operating conditions (pH and polymer/As weight ratio) for As(V) complexation were determined finding values of 7.5/20 and 9.2/30 for PDEHED and polyDADMAC, respectively. The UF tests were performed by continuous diafiltration and diafiltration with volume reduction modes. The latter method permits to save the volume of washing solution during polymer regeneration. As(III) was not complexed, operating under the As(V) complexation conditions, thus a pre-oxidation step by using the photocatalytic approach was carried out to remove As(III) species. As(III) conversion to As(V) was evaluated by As speciation by using the CP-UF process for analytical purposes. Photocatalytic oxidation was successfully performed under UV radiation by using TiO 2 (0.05 mg L -1 ), O 2 and pH = 9. The oxidation was very fast during the first 10 min following a zero order kinetics (k = 0.83 mg L -1  min -1 ) and reaching 90% As(III) oxidation. A conceptual scheme coupling photocatalysis and CP-UF and some criteria to operate the CP-UF process, useful to address it towards application, are reported. Copyright © 2016 Elsevier Ltd. All rights reserved.

Inhibiting core fucosylation attenuates glucose-induced peritoneal fibrosis in rats.

PubMed

Li, Longkai; Shen, Nan; Wang, Nan; Wang, Weidong; Tang, Qingzhu; Du, Xiangning; Carrero, Juan Jesus; Wang, Keping; Deng, Yiyao; Li, Zhitong; Lin, Hongli; Wu, Taihua

2018-06-01

Ultrafiltration failure is a major complication of long-term peritoneal dialysis, resulting in dialysis failure. Peritoneal fibrosis induced by continuous exposure to high glucose dialysate is the major contributor of ultrafiltration failure, for which there is no effective treatment. Overactivation of several signaling pathways, including transforming growth factor-β1 (TGF-β1) and platelet-derived growth factor (PDGF) pathways, contribute to the development of peritoneal fibrosis. Therefore, simultaneously blocking multiple signaling pathways might be a potential novel method of treating peritoneal fibrosis. Previously, we showed that core fucosylation, an important posttranslational modification of the TGF-β1 receptors, can regulate the activation of TGF-β1 signaling in renal interstitial fibrosis. However, it remains unclear whether core fucosylation affects the progression of peritoneal fibrosis. Herein, we show that core fucosylation was enriched in the peritoneal membrane of rats accompanied by peritoneal fibrosis induced by a high glucose dialysate. Blocking core fucosylation dramatically attenuated peritoneal fibrosis in the rat model achieved by simultaneously inactivating the TGF-β1 and PDGF signaling pathways. Next the protective effects of blocking core fucosylation and imatinib (a selective PDGF receptor inhibitor) on peritoneal fibrosis were compared and found to exhibit a greater inhibitory effect over imatinib alone, suggesting that blocking activation of multiple signaling pathways may have superior inhibitory effects on the development of peritoneal fibrosis. Thus, core fucosylation is essential for the development of peritoneal fibrosis by regulating the activation of multiple signaling pathways. This may be a potential novel target for drug development to treat peritoneal fibrosis. Copyright © 2018 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Dialysis modality choice in elderly patients with end-stage renal disease: a narrative review of the available evidence.

PubMed

Segall, Liviu; Nistor, Ionut; Van Biesen, Wim; Brown, Edwina A; Heaf, James G; Lindley, Elizabeth; Farrington, Ken; Covic, Adrian

2017-01-01

The number of elderly patients on maintenance dialysis has rapidly increased in the past few decades, particularly in developed countries, imposing a growing burden on dialysis centres. Hence, many nephrologists and healthcare authorities feel that greater emphasis should be placed on the promotion of home dialysis therapies such as peritoneal dialysis (PD) and home haemodialysis (HD). There is currently no general consensus as to the best dialysis modality for elderly patients with end-stage renal disease. In-centre HD is predominant in most countries, although it is widely recognized that PD has several advantages over HD, including the lack of need for vascular access, continuous slow ultrafiltration, less interference with patients' lifestyle and lower costs. Comparisons of outcomes between elderly patients on PD and HD rely on observational studies, as randomized controlled trials are lacking. The results of these studies are variable. However, most of them suggest that survival rates are largely similar between the two modalities, except for elderly patients with diabetes and/or beyond 1-3 years from dialysis initiation, in which cases HD appears to be superior. An equally important aspect to consider when choosing dialysis modality, particularly in this age group, is the quality of life, and in this regard most studies found no significant differences between PD and HD. In these circumstances, we believe that dialysis modality selection should be guided by patient's preference, based on comprehensive and unbiased information. A multidisciplinary team should review elderly patients starting on dialysis, aiming to identify possible barriers to PD and home HD, including physical, visual, cognitive, psychological and social problems, and to overcome such barriers by adequate care, education, psychological counselling and dialysis assistance. © The Author 2015. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Continuous Shear Wave Signals from around a Subducted Seamount Following 2014 Mw 6.8 Slow-slip Event in the Hikurangi Subduction Margin Offshore New Zealand

NASA Astrophysics Data System (ADS)

Iwasaki, Y.; Mochizuki, K.; Ishise, M.; Todd, E. K.; Schwartz, S. Y.; Henrys, S. A.; Savage, M. K.; Sheehan, A.; Ito, Y.; Wallace, L.; Webb, S. C.; Zal, H. J.; Yamada, T.; Shinohara, M.

2017-12-01

From May 2014 to June 2015 a marine seismic and geodetic experiment was conducted at the Hikurangi subduction margin. During this experiment, a slow-slip event (SSE) with equivalent moment magnitude of Mw 6.8 occurred for two weeks starting in late September 2014, directly beneath the ocean bottom seismometer (OBS) network (Wallace et al., 2016). In this study, we used the continuous waveform data recorded by these OBSs. We calculated a cross correlation coefficient between the two horizontal components and applied a polarization analysis every 10 seconds for 30 second-long OBS waveform records. As a result, we detected the continuous arrival of S-wave signals that appeared to have started in the latter half of the SSE. This continuous signal was identified as tremor and its source location was determined by the envelope cross-correlation method (Todd et al., 2017, in prep). Our result, however, suggests that these signals occur continuously rather than as sporadic individual events, and that they last for more than two weeks. Polarization directions changed at the same time and then remained stable through the two week duration. Such stable polarized directions can only be identified during this period. Our analysis requires fewer OBS than other methods for monitoring such S-wave signals, which may enable us to detect as yet unidentified signals in the Hikurangi margin where seismic attenuation has been shown to be large. The continuous signals with a stable polarization direction were only observed at OBS stations in a limited region, which suggests that the signals were generated near the up-dip edge of the slow slip area and surrounding a subducted seamount. Sources of the continuous signals appear to have migrated from south to north . This observation is consistent with the location of individual tremors identified with envelope cross-correlation methods (Todd et al., 2017, in prep). The slow slip along the plate interface circumvented the subducted seamount (Wallace et al., 2016). By comparing our result with the slip distribution, we can put more constraints on relationship between frictional properties along the plate interface and subducting topographic features such as seamounts. Migration of the sources of the continuous signal may further provide us with information on rupture propagation of the slow slip.

Development of an accurate fluid management system for a pediatric continuous renal replacement therapy device

PubMed Central

SANTHANAKRISHNAN, ARVIND; NESTLE, TRENT T.; MOORE, BRIAN L.; YOGANATHAN, AJIT P.; PADEN, MATTHEW L.

2013-01-01

Acute kidney injury is common in critically ill children and renal replacement therapies provide a life saving therapy to a subset of these children. However, there is no Food and Drug Administration approved device to provide pediatric continuous renal replacement therapy (CRRT). Consequently, clinicians adapt approved adult CRRT devices for use in children due to lack of safer alternatives. Complications occur using adult CRRT devices in children due to inaccurate fluid balance (FB) between the volumes of ultrafiltrate (UF) removed and replacement fluid (RF) delivered. We demonstrate the design and validation of a pediatric fluid management system for obtaining accurate instantaneous and cumulative FB. Fluid transport was achieved via multiple novel pulsatile diaphragm pumps. The conservation of volume principle leveraging the physical property of fluid incompressibility along with mechanical coupling via a crankshaft was used for FB. Accuracy testing was conducted in vitro for 8-hour long continuous operation of the coupled UF and RF pumps. The mean cumulative FB error was <1% across filtration flows from 300 mL/hour to 3000 mL/hour. This approach of FB control in a pediatric specific CRRT device would represent a significant accuracy improvement over currently used clinical implementations. PMID:23644618

Predilution versus postdilution during continuous venovenous hemofiltration: a comparison of circuit thrombogenesis.

PubMed

de Pont, Anne-Cornélie J M; Bouman, Catherine S C; Bakhtiari, Kamran; Schaap, Marianne C L; Nieuwland, Rienk; Sturk, Augueste; Hutten, Barbara A; de Jonge, Evert; Vroom, Margreeth B; Meijers, Joost C M; Büller, Harry R

2006-01-01

During continuous venovenous hemofiltration, predilution can prolong circuit survival time, but the underlying mechanism has not been elucidated. The aim of the present study was to compare predilution with postdilution, with respect to circuit thrombogenesis. Eight critically ill patients were treated with both predilutional and postdilutional continuous venovenous hemofiltration in a crossover fashion. A filtration flow of 60 ml/min was used in both modes. We chose blood flows of 140 and 200 ml/min during predilution and postdilution, respectively, to keep the total flow through the hemofilter constant. Extracorporeal circuit pressures were measured hourly, and samples of blood and ultrafiltrate were collected at five different time points. Thrombin-antithrombin complexes and prothrombin fragments F1 + 2 were measured by ELISA, and platelet activation was assessed by flow cytometry. No signs of thrombin generation or platelet activation were found during either mode. During postdilution, baseline platelet count and maximal prefilter pressure had a linear relation, whereas both parameters were inversely related with circuit survival time. In summary, predilution and postdilution did not differ with respect to extracorporeal circuit thrombogenesis. During postdilution, baseline platelet count and maximal prefilter pressure were inversely related with circuit survival time.

Preparation of hydrophilic and antifouling polysulfone ultrafiltration membrane derived from phenolphthalin by copolymerization method

NASA Astrophysics Data System (ADS)

Liu, Zhixiao; Mi, Zhiming; Chen, Chunhai; Zhou, Hongwei; Zhao, Xiaogang; Wang, Daming

2017-04-01

In this task, carboxylated polysulfone (PSF-COOH) was achieved by introducing the monomer of phenolphthalin (PPL) containing carboxyl to the molecule backbone of polysulfone (PSF). And a series of PSF-COOH copolymers with different carboxylation degree was synthesized by adjusting the molar (%) of bisphenol A (BPA) and PPL in direct copolymerization method and was prepared as PSF-COOH ultrafiltration membranes via phase separation method. The effect of PPL molar (%) in copolymers on the morphology, hydrophilicity, permeation flux, antifouling and mechanical properties of membranes was investigated by scanning electron microscope (SEM), atomic force microscope (AFM), water contact angle, ultrafiltration experiments and universal testing machine, respectively. The results showed that with the increased carboxyl content in membranes, the hydrophilicity, permeation fluxes and antifouling properties of membranes gradually increased. When the molar (%) of PPL to BPA was 100:0, the membrane exhibited the highest pure water flux (329.6 L/m2 h) and the maximum flux recovery rate (92.5%). When the content of carboxyl in the membrane was 80% or more, after three cycles of BSA solution (1 g/L) filtration, the flux recovery rate was basically constant or showed a slightly increase. Thus, it can achieve the goal of long term usage without compromising flux.

Evaluation of Membrane Ultrafiltration and Residual Chlorination as a Decentralized Water Treatment Strategy for Ten Rural Healthcare Facilities in Rwanda

PubMed Central

Huttinger, Alexandra; Dreibelbis, Robert; Roha, Kristin; Ngabo, Fidel; Kayigamba, Felix; Mfura, Leodomir; Moe, Christine

2015-01-01

There is a critical need for safe water in healthcare facilities (HCF) in low-income countries. HCF rely on water supplies that may require additional on-site treatment, and need sustainable technologies that can deliver sufficient quantities of water. Water treatment systems (WTS) that utilize ultrafiltration membranes for water treatment can be a useful technology in low-income countries, but studies have not systematically examined the feasibility of this technology in low-income settings. We monitored 22 months of operation of 10 WTS, including pre-filtration, membrane ultrafiltration, and chlorine residual disinfection that were donated to and operated by rural HCF in Rwanda. The systems were fully operational for 74% of the observation period. The most frequent reasons for interruption were water shortage (8%) and failure of the chlorination mechanism (7%). When systems were operational, 98% of water samples collected from the HCF taps met World Health Organization (WHO) guidelines for microbiological water quality. Water quality deteriorated during treatment interruptions and when water was stored in containers. Sustained performance of the systems depended primarily on organizational factors: the ability of the HCF technician to perform routine servicing and repairs, and environmental factors: water and power availability and procurement of materials, including chlorine and replacement parts in Rwanda. PMID:26516883

Ultrafiltration by a compacted clay membrane. I - Oxygen and hydrogen isotopic fractionation. II - Sodium ion exclusion at various ionic strengths.

NASA Technical Reports Server (NTRS)

Coplen, T. B.; Hanshaw, B. B.

1973-01-01

Laboratory experiments were carried out to determine the magnitude of the isotopic fractionation of distilled water and of 0.01N NaCl forced to flow at ambient temperature under a hydraulic pressure drop of 100 bars across a montmorillonite disk compacted to a porosity of 35% by a pressure of 330 bars. The ultrafiltrates in both experiments were depleted in D by 2.5% and in O-18 by 0.8% relative to the residual solution. No additional isotopic fractionation due to a salt-filtering mechanism was observed at NaCl concentrations up to 0.01N. Adsorption is most likely the principal mechanism which produces isotopic fractionation, but molecular diffusion may play a minor role. The results suggest that oxygen and hydrogen isotopic fractionation of ground water during passage through compacted clayey sediments should be a common occurrence, in accord with published interpretations of isotopic data from the Illinois and Alberta basins. It is shown how it is possible to proceed from the ion exchange capacity of clay minerals and, by means of the Donnan membrane equilibrium concept and the Teorell-Meyer-Siever theory, develop a theory to explain why and to what extent ultrafiltration occurs when solutions of known concentration are forced to flow through a clay membrane.

Quickly Screening for Potential α-Glucosidase Inhibitors from Guava Leaves Tea by Bioaffinity Ultrafiltration Coupled with HPLC-ESI-TOF/MS Method.

PubMed

Wang, Lu; Liu, Yufeng; Luo, You; Huang, Kuiying; Wu, Zhenqiang

2018-02-14

Guava leaves tea (GLT) has a potential antihyperglycemic effect. Nevertheless, it is unclear which compound plays a key role in reducing blood sugar. In this study, GLT extract (IC 50 = 19.37 ± 0.21 μg/mL) exhibited a stronger inhibitory potency against α-glucosidase than did acarbose (positive control) at IC 50 = 178.52 ± 1.37 μg/mL. To rapidly identify the specific α-glucosidase inhibitor components from GLT, an approach based on bioaffinity ultrafiltration combined with high performance liquid chromatography coupled to electrospray ionization-time-of-flight-mass spectrometry (BAUF-HPLC-ESI-TOF/MS) was developed. Under the optimal bioaffinity ultrafiltration conditions, 11 corresponding potential α-glucosidase inhibitors with high affinity degrees (ADs) were screened and identified from the GLT extract. Quercetin (IC 50 = 4.51 ± 0.71 μg/mL) and procyanidin B3 (IC 50 = 28.67 ± 5.81 μg/mL) were determined to be primarily responsible for the antihyperglycemic effect, which further verified the established screening method. Moreover, structure-activity relationships were discussed. In conclusion, the BAUF-HPLC-ESI-TOF/MS method could be applied to determine the potential α-glucosidase inhibitors from complex natural products quickly.

Fluctuation of Ultrafiltration Coefficient of Hemodialysis Membrane During Reuse

NASA Astrophysics Data System (ADS)

Arif, Idam; Christin

2010-12-01

Hemodialysis treatment for patient with kidney failure is to regulate body fluid and to excrete waste products of metabolism. The patient blood and the dialyzing solution (dialysate) are flowed counter currently in a dialyzer to allow volume flux of fluid and diffusion of solutes from the blood to the dialysate through a semipermiable membrane. The volume flux of fluid depends on the hydrostatic and the osmotic pressure difference between the blood and the dialysate. It also depends on the membrane parameter that represents how the membrane allows the fluid and the solutes to move across as a result of the pressure difference, known as the ultrafiltration coefficient Kuf. The coefficient depends on the number and the radius of membrane pores for the movement of the fluids and the solutes across the membrane. The measured membrane ultrafiltration coefficient of reused dialyzer shows fluctuation between one uses to another without any significant trend of change. This indicates that the cleaning process carried out before reuse does not cause perfect removal of clots that happen in the previous use. Therefore the unblocked pores are forced to work hardly to obtain targeted volume flux in a certain time of treatment. This may increase the unblocked pore radius. Reuse is stopped when there is indication of blood leakage during the hemodialysis treatment.

Detection of Macromolecular Fractions in HCN Polymers Using Electrophoretic and Ultrafiltration Techniques.

PubMed

Marín-Yaseli, Margarita R; Cid, Cristina; Yagüe, Ana I; Ruiz-Bermejo, Marta

2017-02-01

Elucidating the origin of life involves synthetic as well as analytical challenges. Herein, for the first time, we describe the use of gel electrophoresis and ultrafiltration to fractionate HCN polymers. Since the first prebiotic synthesis of adenine by Oró, HCN polymers have gained much interest in studies on the origins of life due to the identification of biomonomers and related compounds within them. Here, we demonstrate that macromolecular fractions with electrophoretic mobility can also be detected within HCN polymers. The migration of polymers under the influence of an electric field depends not only on their sizes (one-dimensional electrophoresis) but also their different isoelectric points (two-dimensional electrophoresis, 2-DE). The same behaviour was observed for several macromolecular fractions detected in HCN polymers. Macromolecular fractions with apparent molecular weights as high as 250 kDa were detected by tricine-SDS gel electrophoresis. Cationic macromolecular fractions with apparent molecular weights as high as 140 kDa were also detected by 2-DE. The HCN polymers synthesized were fractionated by ultrafiltration. As a result, the molecular weight distributions of the macromolecular fractions detected in the HCN polymers directly depended on the synthetic conditions used to produce these polymers. The implications of these results for prebiotic chemistry will be discussed. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

Use of Enterococcus faecalis and Bacillus atrophaeus as surrogates to establish and maintain laboratory proficiency for concentration of water samples using ultrafiltration.

PubMed

Mapp, Latisha; Klonicki, Patricia; Takundwa, Prisca; Hill, Vincent R; Schneeberger, Chandra; Knee, Jackie; Raynor, Malik; Hwang, Nina; Chambers, Yildiz; Miller, Kenneth; Pope, Misty

2015-11-01

The U.S. Environmental Protection Agency's (EPA) Water Laboratory Alliance (WLA) currently uses ultrafiltration (UF) for concentration of biosafety level 3 (BSL-3) agents from large volumes (up to 100-L) of drinking water prior to analysis. Most UF procedures require comprehensive training and practice to achieve and maintain proficiency. As a result, there was a critical need to develop quality control (QC) criteria. Because select agents are difficult to work with and pose a significant safety hazard, QC criteria were developed using surrogates, including Enterococcus faecalis and Bacillus atrophaeus. This article presents the results from the QC criteria development study and results from a subsequent demonstration exercise in which E. faecalis was used to evaluate proficiency using UF to concentrate large volume drinking water samples. Based on preliminary testing EPA Method 1600 and Standard Methods 9218, for E. faecalis and B. atrophaeus respectively, were selected for use during the QC criteria development study. The QC criteria established for Method 1600 were used to assess laboratory performance during the demonstration exercise. Based on the results of the QC criteria study E. faecalis and B. atrophaeus can be used effectively to demonstrate and maintain proficiency using ultrafiltration. Published by Elsevier B.V.

Influence of Surface Properties of Filtration-Layer Metal Oxide on Ceramic Membrane Fouling during Ultrafiltration of Oil/Water Emulsion.

PubMed

Lu, Dongwei; Zhang, Tao; Gutierrez, Leo; Ma, Jun; Croué, Jean-Philippe

2016-05-03

In this work, ceramic ultrafiltration membranes deposited with different metal oxides (i.e., TiO2, Fe2O3, MnO2, CuO, and CeO2) of around 10 nm in thickness and similar roughness were tested for O/W emulsion treatment. A distinct membrane fouling tendency was observed, which closely correlated to the properties of the filtration-layer metal oxides (i.e., surface hydroxyl groups, hydrophilicity, surface charge, and adhesion energy for oil droplets). Consistent with the distinct bond strength of the surface hydroxyl groups, hydrophilicity of these common metal oxides is quite different. The differences in hydrophilicity consequently lead to different adhesion of these metal oxides toward oil droplets, consistent with the irreversible membrane fouling tendency. In addition, the surface charge of the metal oxide opposite to that of emulsion can help to alleviate irreversible membrane fouling in ultrafiltration. Highly hydrophilic Fe2O3 with the lowest fouling tendency could be a potential filtration-layer material for the fabrication/modification of ceramic membranes for O/W emulsion treatment. To the best of our knowledge, this is the first study clearly showing the correlations between surface properties of filtration-layer metal oxides and ceramic membrane fouling tendency by O/W emulsion.

Performance of ceramic ultrafiltration membranes and fouling behavior of a dye-polysaccharide binary system.

PubMed

Zuriaga-Agustí, E; Alventosa-deLara, E; Barredo-Damas, S; Alcaina-Miranda, M I; Iborra-Clar, M I; Mendoza-Roca, J A

2014-05-01

Ultrafiltration membrane processes have become an established technology in the treatment and reuse of secondary effluents. Nevertheless, membrane fouling arises as a major obstacle in the efficient operation of these systems. In the current study, the performance of tubular ultrafiltration ceramic membranes was evaluated according to the roles exerted by membrane pore size, transmembrane pressure and feed concentration on a binary foulant system simulating textile wastewater. For that purpose, carboxymethyl cellulose sodium salt (CMC) and an azo dye were used as colloidal and organic foulants, respectively. Results showed that a larger pore size enabled more solutes to get adsorbed into the pores, producing a sharp permeate flux decline attributed to the rapid pore blockage. Besides, an increase in CMC concentration enhanced severe fouling in the case of the tighter membrane. Concerning separation efficiency, organic matter was almost completely removed with removal efficiency above 98.5%. Regarding the dye, 93% of rejection was achieved. Comparable removal efficiencies were attributed to the dynamic membrane formed by the cake layer, which governed process performance in terms of rejection and selectivity. As a result, none of the evaluated parameters showed significant influence on separation efficiency, supporting the significant role of cake layer on filtration process. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of Membrane Ultrafiltration and Residual Chlorination as a Decentralized Water Treatment Strategy for Ten Rural Healthcare Facilities in Rwanda.

PubMed

Huttinger, Alexandra; Dreibelbis, Robert; Roha, Kristin; Ngabo, Fidel; Kayigamba, Felix; Mfura, Leodomir; Moe, Christine

2015-10-27

There is a critical need for safe water in healthcare facilities (HCF) in low-income countries. HCF rely on water supplies that may require additional on-site treatment, and need sustainable technologies that can deliver sufficient quantities of water. Water treatment systems (WTS) that utilize ultrafiltration membranes for water treatment can be a useful technology in low-income countries, but studies have not systematically examined the feasibility of this technology in low-income settings. We monitored 22 months of operation of 10 WTS, including pre-filtration, membrane ultrafiltration, and chlorine residual disinfection that were donated to and operated by rural HCF in Rwanda. The systems were fully operational for 74% of the observation period. The most frequent reasons for interruption were water shortage (8%) and failure of the chlorination mechanism (7%). When systems were operational, 98% of water samples collected from the HCF taps met World Health Organization (WHO) guidelines for microbiological water quality. Water quality deteriorated during treatment interruptions and when water was stored in containers. Sustained performance of the systems depended primarily on organizational factors: the ability of the HCF technician to perform routine servicing and repairs, and environmental factors: water and power availability and procurement of materials, including chlorine and replacement parts in Rwanda.

Application of ultrafiltration and stable isotopic amendments to field studies of mercury partitioning to filterable carbon in lake water and overland runoff

USGS Publications Warehouse

Babiarz, Christopher L.; Hurley, J.P.; Krabbenhoft, D.P.; Gilmour, C.; Branfireun, B.A.

2003-01-01

Results from pilot studies on colloidal phase transport of newly deposited mercury in lake water and overland runoff demonstrate that the combination of ultrafiltration, and stable isotope amendment techniques is a viable tool for the study of mercury partitioning to filterable carbon. Ultrafiltration mass balance calculations were generally excellent, averaging 97.3, 96.1 and 99.8% for dissolved organic carbon (DOC), total mercury (HgT), and methylmercury (MeHg), respectively. Sub nanogram per liter quantities of isotope were measurable, and the observed phase distribution from replicate ultrafiltration separations on lake water agreed within 20%. We believe the data presented here are the first published colloidal phase mercury data on lake water and overland runoff from uncontaminated sites. Initial results from pilot-scale lake amendment experiments indicate that the choice of matrix used to dissolve the isotope did not affect the initial phase distribution of the added mercury in the lake. In addition there was anecdotal evidence that native MeHg was either recently produced in the system, or at a minimum, that this 'old' MeHg partitions to the same subset of DOC that binds the amended mercury. Initial results from pilot-scale overland runoff experiments indicate that less than 20% of newly deposited mercury was transported in the filterable fraction (<0.7 ??m). There is some indication of colloidal phase enrichment of mercury in runoff compared to the phase distribution of organic carbon, but the mechanism of this enrichment is unclear. The phase distribution of newly deposited mercury can differ from that of organic carbon and native mercury, suggesting that the quality of the carbon (available ligands), not the quantity of carbon, regulates partitioning. Further characterization of DOC is needed to clarify the underlying mechanisms. ?? 2002 Elsevier Science B.V. All rights reserved.

Competitive binding experiments can reduce the false positive results of affinity-based ultrafiltration-HPLC: A case study for identification of potent xanthine oxidase inhibitors from Perilla frutescens extract.

PubMed

Wang, Zhiqiang; Kwon, Shin Hwa; Hwang, Seung Hwan; Kang, Young-Hee; Lee, Jae-Yong; Lim, Soon Sung

2017-03-24

The purpose of this study was to assess the possibility of using competitive binding experiments with ultrafiltration-HPLC analysis to identify potent xanthine oxidase (XO) inhibitors from the Perilla frutescens extract as an attempt to reduce the number of false positive results. To isolate the enzyme-ligand complex from unbound compounds, the P. frutescens extract was either incubated in the absence of XO, in the presence of XO, or with the active site blocked XO before the ultrafiltration was performed. Allopurinaol was used as the XO active site blocker. The unbound compounds were subjected to HPLC analysis. The degree of total binding (TBD) and degree of specific binding (SBD) of each compound were calculated using the peak areas. TBD represents the binding affinities of compounds from the P. frutescens extract for the XO binding site. SBD represents the XO competitive binding between allopurinol and ligands from the extract samples. Two criteria were applied to select putative targets that could help avoid false positives. These include TBD>30% and SBD>10%. Using that approach, kaempferol-3-O-rutinoside, rosmarinic acid, methyl-rosmarinic acid, apigenin, and 4',5,7-trimethoxyflavone were identified, from total 11 compounds, as potent XO inhibitors. Finally, apigenin, 4',5,7-trimethoxyflavone, and luteolin were XO inhibitors verified through an XO inhibition assay and structural simulation of the complex. These results showed that the newly developed strategy has the advantage that the number of targets identified via ultrafiltration-HPLC can be narrowed from many false positives. However, not all false positives can be eliminated with this approach. Some potent inhibitors might also be excluded with the use of this method. The limitations of this method are also discussed herein. Copyright © 2017 Elsevier B.V. All rights reserved.

Validation of a highly sensitive ICP-MS method for the determination of platinum in biofluids: application to clinical pharmacokinetic studies with oxaliplatin.

PubMed

Morrison, J G; White, P; McDougall, S; Firth, J W; Woolfrey, S G; Graham, M A; Greenslade, D

2000-12-01

ELOXATIN (Oxaliplatin) is a novel platinum containing anti-cancer agent with a diaminocyclohexane carrier ligand which has been approved in several major European countries. Clinical studies have demonstrated that the compound exhibits marked activity against colorectal cancers in combination with 5-fluorouracil (5-FU). The aim of this work was to develop and validate a highly sensitive inductively coupled plasma mass spectrometry assay for the determination of oxaliplatin-derived platinum in plasma ultrafiltrate, plasma and whole blood and to apply this technique to clinical pharmacokinetic studies with oxaliplatin. Ultratrace detection of platinum in plasma ultrafiltrate was achieved using ultrasonic nebulisation combined with ICP-MS. This technique allows detection of platinum at the 0.001 microg Pt/ml level in only 100 microl of matrix. Assays in blood and plasma utilised a standard Meinhardt nebuliser and spray chamber, achieving detection limits of 0.1 microg Pt/ml in 100 and 200 microl of matrix, respectively. The assays were validated (accuracy and precision within +/- 15%) over the concentration ranges: 0.001-0.250 microg Pt/ml in plasma ultrafiltrate and 0.1-10 microg Pt/ml for plasma and whole blood. The effect of sample digestion. dilution, long term frozen storage and quantitation in the presence of 5-FU were also investigated and validated. The method was used to monitor platinum exposure following oxaliplatin administration (130 mg/m2) to cancer patients. Following a 2 h i.v. infusion, peak platinum levels declined in a triphasic manner in all blood compartments. Free platinum was detected in plasma ultrafiltrate at low levels (0.001 0.010 microg Pt/ml) for up to 3 weeks. In conclusion, a highly sensitive and specific assay has been developed for the determination of platinum in biofluids. This method enabled characterisation of the long term exposure to platinum in patients following oxaliplatin treatment.

Dialyzer clearances and mass transfer-area coefficients for small solutes at low dialysate flow rates.

PubMed

Leypoldt, John K; Kamerath, Craig D; Gilson, Janice F; Friederichs, Goetz

2006-01-01

New daily hemodialysis therapies operate at low dialysate flow rates to minimize dialysate volume requirements; however, the dependence of dialyzer clearances and mass transfer-area coefficients for small solutes on dialysate flow rate under these conditions have not been studied extensively. We evaluated in vitro dialyzer clearances for urea and creatinine at dialysate flow rates of 40, 80, 120, 160, and 200 ml/min and ultrafiltration flow rates of 0, 1, and 2 l/h, using a dialyzer containing PUREMA membranes (NxStage Medical, Lawrence, MA). Clearances were measured directly across the dialyzer by perfusing bovine blood with added urea and creatinine single pass through the dialyzer at a nominal blood flow rate of 400 ml/min. Limited, additional studies were performed with the use of dialyzers containing PUREMA membranes at a blood flow rate of 200 ml/min and also with the use of other dialyzers containing polysulfone membranes (Optiflux 160NR, FMC-NA, Ogden, UT) and dialyzers containing Synphan membranes (NxStage Medical). For dialyzers containing PUREMA membranes, urea and creatinine clearances increased (p < 0.001) with increasing dialysate and ultrafiltration flow rates but were not different at blood flow rates of 200 and 400 ml/min. Dialysate saturation, defined as dialysate outlet concentration divided by blood water inlet concentration, for urea and creatinine was independent of blood and ultrafiltration flow rate but varied inversely (p < 0.001) with dialysate flow rate. Mass transfer-area coefficients for urea and creatinine were independent of blood and ultrafiltration flow rate but decreased (p < 0.001) with decreasing dialysate flow rate. Calculated mass transfer-area coefficients at low dialysate flow rates for all dialyzers tested were substantially lower than those reported by the manufacturers under conventional conditions. We conclude that dialyzers require specific characterization under relevant conditions if they are used in novel daily hemodialysis therapies at low dialysate flow rate.

Association of calcium with colloidal particles and speciation of calcium in the Kalix and Amazon rivers

NASA Astrophysics Data System (ADS)

Dahlqvist, Ralf; Benedetti, Marc F.; Andersson, Karen; Turner, David; Larsson, Tobias; Stolpe, Björn; Ingri, Johan

2004-10-01

A considerable amount of colloidally bound Ca has been detected in water samples from Amazonian rivers and the Kalix River, a sub-arctic boreal river. Fractionation experiments using several analytical techniques and processing tools were conducted in order to elucidate the matter. Results show that on average 84% of the total Ca concentration is present as free Ca. Particulate, colloidal and complexed Ca constitute the remaining 16%, of which the colloidal fraction is significant. Ultrafiltration experiments show that the colloidal fraction in the sampled Amazonian rivers and the Kalix River range between 1% and 25%. In both the Amazonian and the Kalix rivers the technique of cross-flow ultrafiltration was used to isolate particles and colloids. The difference in concentration measured with ICP-AES and a Ca ion-selective electrode in identical samples was used to define the free Ca concentration and thus indirectly the magnitude of the particulate, colloidal and complexed fractions. Results from the Kalix and Amazonian rivers are in excellent agreement. Furthermore, the results show that the colloidal concentrations of Ca can be greatly overestimated (up to 227%) when conventional analysis and calculation of ultrafiltration data is used due to retention of free Ca ions during the ultrafiltration process. Calculation methods for colloidal matter are presented in this work, using complementary data from ISE analysis. In the Kalix River temporal changes in the fractionation of Ca were studied before, during and after a spring-flood event. Changes in the size distribution of colloidally associated Ca was studied using FlFFF (Flow Field-Flow Fractionation) coupled on-line to a HR ICP-MS. The FlFFF-HR ICP-MS fractograms clearly show the colloidal component of Ca, supporting the ultrafiltration findings. During winter conditions the size distribution of colloidally associated Ca has a concentration maximum at ˜5 to 10 nm in diameter, shifting to smaller sizes (<5 nm) during and after the spring flood. This shift in size distribution follows a change in the river during this period from ironoxyhydroxy colloids being the most important colloidal carrier phase to humic substances during and after the spring flood. WHAM and NICA-Donnan models were used to calculate the amount of colloidally bound Ca. The results similar for both models, show that on average 16% of the Ca may be associated to a colloidal phase, which is in broad agreement with the measurements.

Vagus Nerve Stimulation for Electrographic Status Epilepticus in Slow-Wave Sleep.

PubMed

Carosella, Christopher M; Greiner, Hansel M; Byars, Anna W; Arthur, Todd M; Leach, James L; Turner, Michele; Holland, Katherine D; Mangano, Francesco T; Arya, Ravindra

2016-07-01

Electrographic status epilepticus in slow sleep or continuous spike and waves during slow-wave sleep is an epileptic encephalopathy characterized by seizures, neurocognitive regression, and significant activation of epileptiform discharges during nonrapid eye movement sleep. There is no consensus on the diagnostic criteria and evidence-based optimal treatment algorithm for children with electrographic status epilepticus in slow sleep. We describe a 12-year-old girl with drug-resistant electrographic status epilepticus in slow wave sleep that was successfully treated with vagus nerve stimulation. Her clinical presentation, presurgical evaluation, decision-making, and course after vagus nerve stimulator implantation are described in detail. After vagus nerve stimulator implantation, the girl remained seizure free for more than a year, resolved the electrographic status epilepticus in slow sleep pattern on electroencephalography, and exhibited significant cognitive improvement. Vagus nerve stimulation may be considered for electrographic status epilepticus in slow sleep. Copyright © 2016 Elsevier Inc. All rights reserved.

Secondary wastewater polishing with ultrafiltration membranes for unrestricted reuse: fouling and flushing modeling.

PubMed

Gillerman, Leonid; Bick, Amos; Buriakovsky, Nisan; Oron, Gideon

2006-11-01

The effects of operating parameters such astransmembrane pressure, retentate, and recirculation volumetric flow rates on the productivity of an ultrafiltration membrane were studied using field data and development of a management model. Correlation equations for predicting the volumetric permeate flow rates were derived from general membrane blocking laws and experimental data. The experimental data were obtained from a pilot study carried out in the Arad wastewater treatment system (a pilot plant operating in feed and bleed operation mode) located several kilometers west of the City of Arad, Israel. Correlation predictions were confirmed with the independent experimental results. The results enabled us to develop a mathematical expression accurately describing the decline in flux due to fouling.

Concentration and separation of biological organisms by ultrafiltration and dielectrophoresis

DOEpatents

Simmons, Blake A.; Hill, Vincent R.; Fintschenko, Yolanda; Cummings, Eric B.

2010-10-12

Disclosed is a method for monitoring sources of public water supply for a variety of pathogens by using a combination of ultrafiltration techniques together dielectrophoretic separation techniques. Because water-borne pathogens, whether present due to "natural" contamination or intentional introduction, would likely be present in drinking water at low concentrations when samples are collected for monitoring or outbreak investigations, an approach is needed to quickly and efficiently concentrate and separate particles such as viruses, bacteria, and parasites in large volumes of water (e.g., 100 L or more) while simultaneously reducing the sample volume to levels sufficient for detecting low concentrations of microbes (e.g., <10 mL). The technique is also designed to screen the separated microbes based on specific conductivity and size.

Effect of membrane properties on the performance of a hybrid GAC and ultrafiltration process for water treatment.

PubMed

Qiao, Tiejun; Wu, Guangxue; Zhang, Xihui; Au, Doris W T; Zhang, Jinsong

2012-06-01

The performance of a hybrid granular activated carbon (GAC) and ultrafiltration (UF) process for water treatment was investigated using five types of UF membranes. The removal percentages for chemical oxygen demand (COD(Mn)), particles (> or = 2 microm) and total bacteria by the hybrid process were 30-40%, 98-99% and 76-92%, respectively. No invertebrates were detected in the hybrid process effluent. Transmembrane pressure and specific permeate flux (SPF) of the five types of membranes varied. With decreasing membrane pore sizes, removal of COD(Mn) and particles increased, whereas SPF firstly decreased and then increased. Hydrophilic membranes had a relatively high COD(Mn) removal potential, but did not obviously affect particle removal or SPF.

[Study on assistant cleaning of ultrasound for the ultrafiltration membrane].

PubMed

Zhang, Guojun; Liu, Zhongzhou

2003-11-01

The effects of ultrasounds with different frequency on membrane performance were investigated in this paper. The experimental results show that there were nearly no effects of 20 W ultrasound on membrane retention coefficient, but it decreased seriously when the ultrasound power was above 30 W. On the basis of these results, low frequency ultrasound (20 W) was introduced to assist the chemical cleaning in the ultrafiltration process of wastewater from bank note printing works. The cleaning time could be shortened from 20-30 min to 5 min by the ultra-liberation and ultra-blend effects of ultrasound, therefore, the cleaning efficiency was highly improved. However, the fouling substances could not be cleaned entirely in the simple physical cleaning process by SEM analysis.

Analysis of the low molecular weight serum peptidome using ultrafiltration and a hybrid ion trap-Fourier transform mass spectrometer.

PubMed

Zheng, Xiaoyang; Baker, Haven; Hancock, William S

2006-07-07

Advances in proteomics are continuing to expand the ability to analyze the serum proteome. In recent years, it has been realized that in addition to the circulating proteins, human serum also contains a large number of peptides. Many of these peptides are believed to be fragments of larger proteins that have been at least partially degraded by various enzymes such as metalloproteases. Identifying these peptides from a small amount of serum/plasma is difficult due to the complexity of the sample, the low levels of these peptides, and the difficulties in getting a protein identification from a single peptide. In this study, we modified previously published protocols for using centrifugal ultrafiltration, and unlike past studies did not digest the filtrate with trypsin with the intent of identifying endogenous peptides with this method. The filtrate fraction was concentrated and analyzed by a reversed phase-high performance liquid chromatography system connected to a nanospray ionization hybrid ion trap-Fourier transform mass spectrometer (LTQ-FTMS). The mass accuracy of this instrument allows confidence for identifying the protein precursors by a single peptide. The utility of this approach was demonstrated by the identification of over 300 unique peptides with 2 ppm or better mass accuracy per serum sample. With confident identifications, the origin and function of native serum peptides can be more seriously explored. Interestingly, over 34 peptide ladders were observed from over 17 serum proteins. This indicates that a cascade of proteolytic processes affects the serum peptidome. To examine whether this result was an artifact of serum, matched plasma and serum samples were analyzed with similar peptide ladders found in each.

Multipass haemodialysis: a novel dialysis modality

PubMed Central

Heaf, James Goya; Axelsen, Mette; Pedersen, Robert Smith

2013-01-01

Introduction Most home haemodialysis (HD) modalities are limited to home use since they are based on a single-pass (SP) technique, which requires preparation of large amounts of dialysate. We present a new dialysis method, which requires minimal dialysate volumes, continuously recycled during treatment [multipass HD (MPHD)]. Theoretical calculations suggest that MPHD performed six times weekly for 8 h/night, using a dialysate bath containing 50% of the calculated body water, will achieve urea clearances equivalent to conventional HD 4 h thrice weekly, and a substantial clearance of higher middle molecules. Methods Ten stable HD patients were dialyzed for 4 h using standard SPHD (dialysate flow 500 mL/min). Used dialysate was collected. One week later, an 8-h MPHD was performed. The dialysate volume was 50% of the calculated water volume, the dialysate inflow 500 mL/min−0.5 × ultrafiltration/min and the outflow 500 mL/min + 0.5 × ultrafiltration/min. Elimination rates of urea, creatinine, uric acid, phosphate and β2-microglobulin (B2M) and dialysate saturation were determined hourly. Results Three hours of MPHD removed 49, 54, 50, 51 and 57%, respectively, of the amounts of urea, creatinine, uric acid, phosphate and B2M that were removed by 4 h conventional HD. The corresponding figures after 8 h MPHD were 63, 78, 74, 78 and 111%. Conclusions Clearance of small molecules using MPHD 6 × 8 h/week will exceed traditional HD 3 × 4 h/week. Similarly, clearance of large molecules will significantly exceed traditional HD and HD 5 × 2.5 h/week. This modality will increase patients' freedom of movement compared with traditional home HD. The new method can also be used in the intensive care unit and for automated peritoneal dialysis. PMID:23136214

Slow movement execution in event-related potentials (P300).

PubMed

Naruse, Kumi; Sakuma, Haruo; Hirai, Takane

2002-02-01

We examined whether slow movement execution has an effect on cognitive and information processing by measuring the P300 component. 8 subjects performed a continuous slow forearm rotational movement using 2 task speeds. Slow (a 30-50% decrease from the subject's Preferred speed) and Very Slow (a 60-80% decrease). The mean coefficient of variation for rotation speed under Very Slow was higher than that under Slow, showing that the subjects found it difficult to perform the Very Slow task smoothly. The EEG score of alpha-1 (8-10 Hz) under Slow Condition was increased significantly more than under the Preferred Condition; however, the increase under Very Slow was small when compared with Preferred. After performing the task. P300 latency under Very Slow increased significantly as compared to that at pretask. Further, P300 amplitude decreased tinder both speed conditions when compared to that at pretask, and a significant decrease was seen under the Slow Condition at Fz, whereas the decrease under the Very Slow Condition was small. These differences indicated that a more complicated neural composition and an increase in subjects' attention might have been involved when the task was performed under the Very Slow Condition. We concluded that slow movement execution may have an influence on cognitive function and may depend on the percentage of decrease from the Preferred speed of the individual.

Anomalous versus Slowed-Down Brownian Diffusion in the Ligand-Binding Equilibrium

PubMed Central

Soula, Hédi; Caré, Bertrand; Beslon, Guillaume; Berry, Hugues

2013-01-01

Measurements of protein motion in living cells and membranes consistently report transient anomalous diffusion (subdiffusion) that converges back to a Brownian motion with reduced diffusion coefficient at long times after the anomalous diffusion regime. Therefore, slowed-down Brownian motion could be considered the macroscopic limit of transient anomalous diffusion. On the other hand, membranes are also heterogeneous media in which Brownian motion may be locally slowed down due to variations in lipid composition. Here, we investigate whether both situations lead to a similar behavior for the reversible ligand-binding reaction in two dimensions. We compare the (long-time) equilibrium properties obtained with transient anomalous diffusion due to obstacle hindrance or power-law-distributed residence times (continuous-time random walks) to those obtained with space-dependent slowed-down Brownian motion. Using theoretical arguments and Monte Carlo simulations, we show that these three scenarios have distinctive effects on the apparent affinity of the reaction. Whereas continuous-time random walks decrease the apparent affinity of the reaction, locally slowed-down Brownian motion and local hindrance by obstacles both improve it. However, only in the case of slowed-down Brownian motion is the affinity maximal when the slowdown is restricted to a subregion of the available space. Hence, even at long times (equilibrium), these processes are different and exhibit irreconcilable behaviors when the area fraction of reduced mobility changes. PMID:24209851

Trends in cancer mortality in Spain: the influence of the financial crisis.

PubMed

Ferrando, Josep; Palència, Laia; Gotsens, Mercè; Puig-Barrachina, Vanessa; Marí-Dell'Olmo, Marc; Rodríguez-Sanz, Maica; Bartoll, Xavier; Borrell, Carme

2018-02-13

To determine if the onset of the economic crisis in Spain affected cancer mortality and mortality trends. We conducted a longitudinal ecological study based on all cancer-related deaths and on specific types of cancer (lung, colon, breast and prostate) in Spain between 2000 and 2013. We computed age-standardised mortality rates in men and women, and fit mixed Poisson models to analyse the effect of the crisis on cancer mortality and trends therein. After the onset of the economic crisis, cancer mortality continued to decline, but with a significant slowing of the yearly rate of decline (men: RR = 0.987, 95%CI = 0.985-0.990, before the crisis, and RR = 0.993, 95%CI = 0.991-0.996, afterwards; women: RR = 0.990, 95%CI = 0.988-0.993, before, and RR = 1.002, 95%CI = 0.998-1.006, afterwards). In men, lung cancer mortality was reduced, continuing the trend observed in the pre-crisis period; the trend in colon cancer mortality did not change significantly and continued to increase; and the yearly decline in prostate cancer mortality slowed significantly. In women, lung cancer mortality continued to increase each year, as before the crisis; colon cancer continued to decease; and the previous yearly downward trend in breast cancer mortality slowed down following the onset of the crisis. Since the onset of the economic crisis in Spain the rate of decline in cancer mortality has slowed significantly, and this situation could be exacerbated by the current austerity measures in healthcare. Copyright © 2018 SESPAS. Publicado por Elsevier España, S.L.U. All rights reserved.

Telemedicine Project Brings Continuing Education to Rural Doctors.

ERIC Educational Resources Information Center

Technological Horizons in Education, 1980

1980-01-01

Describes a project in Northern Ontario, Canada, demonstrating the feasibility of slow-scan television as a viable and low-cost communications medium for remote diagnosis and teaching. Slow-scan TV allows motionless pictures, such as X-rays, EKGs, charts, or photographs, to be transmitted over normal telephone lines. (JN)

Continuous centrifuge decelerator for polar molecules.

PubMed

Chervenkov, S; Wu, X; Bayerl, J; Rohlfes, A; Gantner, T; Zeppenfeld, M; Rempe, G

2014-01-10

Producing large samples of slow molecules from thermal-velocity ensembles is a formidable challenge. Here we employ a centrifugal force to produce a continuous molecular beam with a high flux at near-zero velocities. We demonstrate deceleration of three electrically guided molecular species, CH3F, CF3H, and CF3CCH, with input velocities of up to 200  m s(-1) to obtain beams with velocities below 15  m s(-1) and intensities of several 10(9)  mm(-2) s(-1). The centrifuge decelerator is easy to operate and can, in principle, slow down any guidable particle. It has the potential to become a standard technique for continuous deceleration of molecules.

Eco-Friendly Superwetting Material for Highly Effective Separations of Oil/Water Mixtures and Oil-in-Water Emulsions.

PubMed

Wang, Chih-Feng; Yang, Sheng-Yi; Kuo, Shiao-Wei

2017-02-20

Because the treatment of oily wastewater, generated from many industrial processes, has become an increasing environmental concern, the search continues for simple, inexpensive, eco-friendly, and readily scalable processes for fabricating novel materials capable of effective oil/water separation. In this study we prepared an eco-friendly superhydrophilic and underwater superoleophobic polyvinylpyrrolidone (PVP)-modified cotton that mediated extremely efficient separations of mixtures of oil/water and oil/corrosive solutions. This PVP-modified cotton exhibited excellent antifouling properties and could be used to separate oil/water mixtures continuously for up to 20 h. Moreover, the compressed PVP-modified cotton could separate both surfactant-free and -stabilized oil-in-water emulsions with fluxes of up to 23,500 L m -2 h -1 bar -1 -a level one to two orders of magnitude higher than that possible when using traditional ultrafiltration membranes having similar rejection properties. The high performance of our PVP-modified cotton and its green, low-energy, cost-effective preparation suggest its great potential for practical applications.

Eco-Friendly Superwetting Material for Highly Effective Separations of Oil/Water Mixtures and Oil-in-Water Emulsions

NASA Astrophysics Data System (ADS)

Wang, Chih-Feng; Yang, Sheng-Yi; Kuo, Shiao-Wei

2017-02-01

Because the treatment of oily wastewater, generated from many industrial processes, has become an increasing environmental concern, the search continues for simple, inexpensive, eco-friendly, and readily scalable processes for fabricating novel materials capable of effective oil/water separation. In this study we prepared an eco-friendly superhydrophilic and underwater superoleophobic polyvinylpyrrolidone (PVP)-modified cotton that mediated extremely efficient separations of mixtures of oil/water and oil/corrosive solutions. This PVP-modified cotton exhibited excellent antifouling properties and could be used to separate oil/water mixtures continuously for up to 20 h. Moreover, the compressed PVP-modified cotton could separate both surfactant-free and -stabilized oil-in-water emulsions with fluxes of up to 23,500 L m-2 h-1 bar-1—a level one to two orders of magnitude higher than that possible when using traditional ultrafiltration membranes having similar rejection properties. The high performance of our PVP-modified cotton and its green, low-energy, cost-effective preparation suggest its great potential for practical applications.

Eco-Friendly Superwetting Material for Highly Effective Separations of Oil/Water Mixtures and Oil-in-Water Emulsions

PubMed Central

Wang, Chih-Feng; Yang, Sheng-Yi; Kuo, Shiao-Wei

2017-01-01

Because the treatment of oily wastewater, generated from many industrial processes, has become an increasing environmental concern, the search continues for simple, inexpensive, eco-friendly, and readily scalable processes for fabricating novel materials capable of effective oil/water separation. In this study we prepared an eco-friendly superhydrophilic and underwater superoleophobic polyvinylpyrrolidone (PVP)-modified cotton that mediated extremely efficient separations of mixtures of oil/water and oil/corrosive solutions. This PVP-modified cotton exhibited excellent antifouling properties and could be used to separate oil/water mixtures continuously for up to 20 h. Moreover, the compressed PVP-modified cotton could separate both surfactant-free and -stabilized oil-in-water emulsions with fluxes of up to 23,500 L m−2 h−1 bar−1—a level one to two orders of magnitude higher than that possible when using traditional ultrafiltration membranes having similar rejection properties. The high performance of our PVP-modified cotton and its green, low-energy, cost-effective preparation suggest its great potential for practical applications. PMID:28216617

Magnetic-field-dependent slow light in strontium atom-cavity system

NASA Astrophysics Data System (ADS)

Liu, Zeng-Xing; Wang, Bao; Kong, Cui; Xiong, Hao; Wu, Ying

2018-03-01

Realizing and controlling a long-lived slow light is of fundamental importance in physics and may find applications in quantum router and quantum information processing. In this work, we propose a feasible scheme to realize the slow light in a strontium atom-cavity system, in which the value of group delay can be continuously adjusted within a range of different Zeeman splittings and vacuum Rabi frequencies by varying the applied static magnetic field and the atom number instead of a strong coherent field. In our scheme, the major limitations of the slow-light structure, namely, dispersion and loss, can be effectively resolved, and so our scheme may help to achieve the practical application of slow light relevant to the optical communication network.

Colloid particle sizes in the Mississippi River and some of its tributaries, from Minneapolis to below New Orleans

USGS Publications Warehouse

Rostad, C.E.; Rees, T.F.; Daniel, S.R.

1998-01-01

An on-board technique was developed that combined discharge-weighted pumping to a high-speed continuous-flow centrifuge for isolation of the particulate-sized material with ultrafiltration for isolation of colloid-sized material. In order to address whether these processes changed the particle sizes during isolation, samples of particles in suspension were collected at various steps in the isolation process to evaluate changes in particle size. Particle sizes were determined using laser light-scattering photon correlation spectroscopy and indicated no change in size during the colloid isolation process. Mississippi River colloid particle sizes from twelve sites from Minneapolis to below New Orleans were compared with sizes from four tributaries and three seasons, and from predominantly autochthonous sources upstream to more allochthonous sources downstream. ?? 1998 John Wiley Sons, Ltd.

Active immunisation of black tiger prawn (Penaeus monodon) against vibriosis in Thailand.

PubMed

Böhnel, H; Lohavanijaya, P; Rungin, S; Schnug, C; Seifert, H S

1999-08-01

Mechanisms of host defence in Crustaceae and vibriosis in shrimp and methods for its prevention are discussed as introduction. The own work deals with the development of a site-specific multivalent anti-vibrio vaccine and its application in Thailand. The vaccine was produced in a continuous bioreactor system from field strains of Vibrio alginolyticus, V. harveyi, V. parahaemolyticus and V. vulnificus, purified through ultrafiltration, and inactivated by formalin. It was applied to Penaeus monodon PL prior to release into the ponds via artemia larvae. As mean result from numerous trials carried out under commercial field conditions in Eastern Thailand it was shown that the PL tolerated the vaccine perfectly. Due to technical problems only few of the field trials could be monitored until harvest. The data available allow claiming an obvious protective effect of the vaccine.

Time dependent deformation of Kilauea Volcano, Hawaii

NASA Astrophysics Data System (ADS)

Montgomery-Brown, Emily Kvietka Desmarais

In 1997 the continuous Global Positioning System (GPS) network was completed on Kilauea, providing the first network of daily position measurements during eruptions and earthquakes on Kilauea. Kilauea has been studied for many decades with continuous seismic and tilt instruments. Other geodetic data (e.g., campaign GPS, leveling, electronic distance measurements) are also available although they contain only sparse data. Data analysis methods used here include inverting multiple data sets for optimal source parameters and the spatio-temporal distribution of magma volume and fault slip, and combining GPS and seismic observations to understand flank tectonics. The field area for this study, Kilauea Volcano, was chosen because of its frequent activity and potential hazards. The 1997 East Rift Zone eruption (Episode 54) was the first major event to occur after the completion of the continuous GPS network. The event lasted 2 days, but transient deformation continued for six months. This long-duration transient allowed the first spatio-temporal study of transient dike deformation on Kilauea from daily GPS positions. Slow-slip events were discovered on Kilauea during which the southern flank of the volcano would accelerate seaward for approximately 2 days. The discovery was made possible because of the continuously operating GPS network. These slip events were also observed to correlate with small swarms of microearthquakes found to follow temporal pattern consistent with them being co- and aftershocks of the slow-slip event (Segall, 2006). Half-space models of geodetic data favor a shallow fault plane (˜ 5 km), which is much too shallow to have increased the Coulomb stress at the depths of the co- and aftershocks. However, optimizations for the slow-slip source parameters including a layered elastic structure and a topographic correction favor deeper models within the range of the co- and aftershocks. Additionally, the spatial distribution of seaward fault slip, fixed to a decollement structure 8 km under the south flank, and the locations of the microearthquakes suggest that both occur on the same structure. In 2007, Episode 56 of the Pu'u 'O'o-Kupianaha eruption occurred. This episode was exciting both because it was the largest intrusion in the last decade, and because it occurred concurrently with a flank slow-slip event. The intrusion started on Father's day (June 17th), 2007 with increased seismicity and abrupt tilts at the summit and rift zones. Quasi-static models of the total deformation determined from GPS, tilt, and InSAR indicate that the intrusion occurred on two en echelon dike segments in the upper East Rift Zone along with deformation consistent with slow-slip in the same areas of previous events. The ˜ 2 m maximum opening occurred on the eastern segment near Makaopui crater. Unlike previous intrusions in 1997, 1999, and 2000, the dike model was not sufficient to explain deformation on the western flank. Additionally, a coastal tiltmeter installed in anticipation of a slow-slip event recorded tilts consistent with those observed during the 2005 slow-slip event. These observations led to the conclusion that a concurrent slow-slip event occurred. Geodetic models indicate a similar amount of decollement slip occurred as in previous slow-slip events. Sub-daily GPS positions were used to study the spatio-temporal distribution of the dike intrusion. The time-dependent intrusion model shows that the intrusion began on the western en echelon segment before jumping to the eastern segment, which accumulated the majority of the 2 m of opening. Sub-daily GPS positions limit the number of stations available since there are very few continuous stations north of the East Rift Zone, where coverage is critical for separating the intrusion from the slow-slip. However, an ENVISAT interferogram at 08:22 on June 18, 2007 provides additional spatial coverage of deformation up to that point. Combining this image with the GPS and tilt data up to that point, we perform a quasi-static inversion for the intrusion source. The residual deformation indicates that slow-slip had not significantly progressed by the ENVISAT image. The slow-slip event occurred therefore at least 20 hours after the initiation of the dike intrusion. (Abstract shortened by UMI.)

Screening and identification of α-glucosidase inhibitors from Shenqi Jiangtang Granule by ultrafiltration liquid chromatography and mass spectrometry.

PubMed

Zhang, Hui; Zhang, Xiaojing; Jiang, Huijie; Xu, Cong; Tong, Shengqiang; Yan, Jizhong

2018-02-01

Shenqi Jiangtang Granule, a well-known traditional Chinese herbal preparation, has been widely used for the treatment of type II diabetes mellitus. In this work, an ultrafiltration liquid chromatography with quadrupole time-of-flight mass spectrometry method was proposed for the rapid identification of bioactive ingredients from Shenqi Jiangtang Granule using α-glucosidase as an example. First, the chemical profile of this preparation was clarified, including 37 saponins, 17 flavonoids, 37 lignans, and seven other compounds. After incubation with α-glucosidase in vitro, the methanol extract with an IC 50 value of 0.19 mg/mL exhibited significant inhibitory activity. Then, 18 specific binding peaks were screened, and 15 peaks were identified. Among these, ten compounds were reported to have potential α-glucosidase inhibitory activity for the first time. Subsequently, the inhibitory activities of these active compounds were evaluated by ultraviolet spectrophotometry with p-nitrophenyl α-d-glucopyranoside as a substrate. As a result, gomisin J and gomisin D exhibited stronger α-glucosidase inhibitory activities than other active compounds with IC 50 values of 77.69 and 133.85 μM, respectively. The results demonstrated that the integrated ultrafiltration liquid chromatography with mass spectrometry method was an effective and powerful tool for the discovery of active ingredients in Shenqi Jiangtang Granule. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultrafiltration-LC-MS combined with semi-preparative HPLC for the simultaneous screening and isolation of lactate dehydrogenase inhibitors from Belamcanda chinensis.

PubMed

Li, Senlin; Li, Sainan; Tang, Ying; Liu, Chunming; Chen, Lina; Zhang, Yuchi

2016-12-01

Stroke represents the fourth leading cause of death in the USA and the second leading cause of death worldwide. Lactate dehydrogenase inhibitors are widely used in the treatment of ischemic stroke and natural products are considered a promising source of novel lactate dehydrogenase inhibitors. In this study, we used PC12 cells to determine the protective effect of extracts from the herb Belamcanda chinensis following toxic challenge. Using ultrafiltration high-performance liquid chromatography coupled with photo-diode array detection and electrospray ionization mass spectrometry, we screened and identified isoflavonoids from Belamcanda chinensis extracts. Semi-preparative high-performance liquid chromatography was then applied to separate and isolate the active constituents. Using these methods, we identified six major compounds in Belamcanda chinensis as lactate dehydrogenase inhibitors: tectoridin, iristectorin A, iridin, tectorigenin, irigenin, and irisflorentin, which were then isolated to >92% purity. This is the first report that Belamcanda chinensis extracts contain potent lactate dehydrogenase inhibitors. Our results demonstrate that the systematic isolation of bioactive components from Belamcanda chinensis guided by ultrafiltration high-performance liquid chromatography coupled with photo-diode array detection and electrospray ionization mass spectrometry represents a feasible and efficient technique that could be extended for the identification and isolation of other enzyme inhibitors. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interstitial matrix proteins determine hyaluronan reflection and fluid retention in rabbit joints: effect of protease

PubMed Central

Sabaratnam, S; Coleman, P J; Mason, R M; Levick, J R

2007-01-01

Hyaluronan (HA) retention inside the synovial cavity of joints serves diverse protective roles. We tested the hypothesis that HA retention is mediated by the network of extracellular matrix proteins in the synovial lining. Cannulated rabbit knee joints were infused with HA solution with or without pretreatment by chymopapain, a collagen-sparing protease. Trans-synovial fluid escape rate was measured and, after a period of trans-synovial filtration, samples of intra-articular fluid and subsynovial fluid were analysed for HA to assess its trans-synovial ultrafiltration. In control joints, HA ultrafiltration was confirmed by postfiltration increases in intra-articular HA concentration (259 ± 17% of infused concentration) and reduced subsynovial concentration (30 ± 8%; n = 11). The proportion of HA molecules reflected by the synovium was 57–75%. Chymopapain treatment increased the hydraulic permeability of the synovial lining ∼13-fold, almost abolished the trans-synovial difference in HA concentration and reduced the HA reflected fraction to 3–7% (n = 6; P < 0.001, ANOVA). Structural studies confirmed that chymopapain treatment depleted the matrix of proteoglycans but preserved its collagen. The findings thus demonstrate that HA ultrafiltration and synovial hydraulic permeability are determined by the network of non-collagen, extracellular matrix proteins. This may be important clinically, since protease activity is raised in rheumatoid arthritis, as are HA and fluid escape. PMID:17008373

Influence of gas-liquid two-phase flow on angiotensin-I converting enzyme inhibitory peptides separation by ultra-filtration.

PubMed

Charoenphun, Narin; Youravong, Wirote

2017-01-01

Membrane fouling is a major problem in ultra-filtration systems and two-phase flow is a promising technique for permeate flux enhancement. The objective of this research was to study the use of an ultra-filtration (UF) system to enrich angiotensin-I converting enzyme (ACE) inhibitory peptides from tilapia protein hydrolysate. To select the most appropriate membrane and operating condition, the effects of membrane molecular weight cut-off (MWCO), transmembrane pressure (TMP) and cross-flow velocity (CFV) on permeate flux and ACE inhibitory peptide separation were studied. Additionally, the gas-liquid two-phase flow technique was applied to investigate its effect on the process capability. The results showed that the highest ACE inhibitory activity was obtained from permeate of the 1 kDa membrane. In terms of TMP and CFV, the permeate flux tended to increase with TMP and CFV. The use of gas-liquid two-phase flow as indicated by shear stress number could reduce membrane fouling and increase the permeate flux up to 42%, depending on shear stress number. Moreover, the use of a shear stress number of 0.039 led to an augmentation in ACE inhibitory activity of permeates. Operating conditions using a shear stress number of 0.039 were recommended for enrichment of ACE inhibitory peptides. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Removal of Surrogate Bacteriophages and Enteric Viruses from Seeded Environmental Waters Using a Semi-technical Ultrafiltration Unit.

PubMed

Frohnert, Anne; Kreißel, Katja; Lipp, Pia; Dizer, Halim; Hambsch, Beate; Szewzyk, Regine; Selinka, Hans-Christoph

2015-03-19

Experiments to determine the removal of viruses in different types of water (surface water from two reservoirs for drinking water treatment, treated groundwater and groundwater contaminated with either 5 or 30 % of wastewater) by ultrafiltration were performed with a semi-technical ultrafiltration unit. Concentrations of human adenoviruses (HAdVs), murine norovirus (MNV), and the bacteriophages MS2, ΦX174 and PRD1 were measured in the feed water and the filtrate, and log removal values were calculated. Bacteria added to the feed water were not detected in the filtrates. In contrast, in most cases viruses and bacteriophages were still present in the filtrates: log removal values were in the range of 1.4-6.3 depending on virus sizes and water qualities. Best removals were observed with bacteriophage PRD1 and HAdVs, followed by MNV and phages MS2 and ΦX174. Virus size, however, was not the only criterion for efficient removal. In diluted wastewater as compared to drinking water and uncontaminated environmental waters, virus removal was clearly higher for all viruses, most likely due to higher membrane fouling. For quality assessment purposes of membrane filtration efficiencies with regard to the elimination of human viruses the small bacteriophages MS2 and ΦX174 should be used as conservative viral indicators.

Block copolymer self-assembly derived ultrafiltration membranes: From science to start-up

NASA Astrophysics Data System (ADS)

Wiesner, Ulrich

In the last ten years a novel method to generate asymmetric ultrafiltration membranes has been established. It is based on the combination of block copolymer self-assembly with non-solvent induced phase separation (NIPS) and is now referred to as SNIPS. NIPS as an industry proven method for the formation of phase inversion membranes opening a pathway to scale up and commercialization of these membranes. The combination of NIPS with block copolymer self-assembly leads to asymmetric membranes with narrow pore size distributions in the top surface layer (so called isoporous membranes) as well as high pore densities, thereby potentially combining high resolution with high flux in membrane separation processes. Such membranes have potential applications in the biopharmaceutical industry where a large fraction of the costs are currently associated with time-consuming non-membrane based separation processes. This talk will describe a family of isoporous ultrafiltration membranes based on the self-assembly behavior of an ABC triblock terpolymer which has led to the formation of a start-up company out of Cornell University. After introduction of the SNIPS process in general, and its application to such ABC triblock terpolymers in particular, open scientific questions associated with the formation mechanisms of the top surface separation layer in such membranes is discussed, which is at the heart of enabling high performance separation behavior. Furthermore, challenges translating scientific work into industrial settings are highlighted.

Peritoneum: a noble membrane in long-term dialysis treatment.

PubMed

Barone, Roberto J; Campora, María I; Gimenez, Nélida S; Ramirez, Liliana; Santopietro, Mónica; Grbavac, Drago; Pattin, Mauricio; Panese, Sergio A

2009-01-01

The durability of the peritoneum as a dialysis membrane is as yet an unanswered question. Peritonitis episodes have an important effect in long-term treatment. To evaluate survival of the peritoneum for dialysis, we analyzed peritoneal failure related to technique dropout because of peritonitis, inadequate dialysis, and ultrafiltration disorders. We retrospectively analyzed data for 89 peritoneal dialysis patients who had been treated for at least 3 months [52 women, 37 men; mean age: 50.91 +/- 13.72 years (range: 22 - 81 years)] from August 4, 1993, to July 1, 2008. The Kaplan-Meier method was used to measure peritoneum survival, with only a definitive switch to hemodialysis or death from peritonitis, ultrafiltration failure, or inadequate dialysis as endpoints. Total treatment time was 5008 patient-months (mean: 55 +/- 44 patient-months), and the historical annual rate of peritonitis was 0.37 per year at risk (1 episode in 32.52 patient-months). Of the 89 patients, 19 dropped treatment because of peritonitis and 1 because of ultrafiltration failure. Peritoneum survival was 98.8%, 93.7%, 87.6%, 66.9%, 46.4%, and 33.8% at 1, 3, 5, 8, 10, and 14 years. In the 15 years of our program, peritoneum failure represented less than 1.5% of drop-out causes annually. The peritoneum is a reliable membrane to reach dialysis targets in long-term therapy.

Study and optimization of the ultrasound-enhanced cleaning of an ultrafiltration ceramic membrane through a combined experimental-statistical approach.

PubMed

Alventosa-deLara, E; Barredo-Damas, S; Alcaina-Miranda, M I; Iborra-Clar, M I

2014-05-01

Membrane fouling is one of the main drawbacks of ultrafiltration technology during the treatment of dye-containing effluents. Therefore, the optimization of the membrane cleaning procedure is essential to improve the overall efficiency. In this work, a study of the factors affecting the ultrasound-assisted cleaning of an ultrafiltration ceramic membrane fouled by dye particles was carried out. The effect of transmembrane pressure (0.5, 1.5, 2.5 bar), cross-flow velocity (1, 2, 3 ms(-1)), ultrasound power level (40%, 70%, 100%) and ultrasound frequency mode (37, 80 kHz and mixed wave) on the cleaning efficiency was evaluated. The lowest frequency showed better results, although the best cleaning performance was obtained using the mixed wave mode. A Box-Behnken Design was used to find the optimal conditions for the cleaning procedure through a response surface study. The optimal operating conditions leading to the maximum cleaning efficiency predicted (32.19%) were found to be 1.1 bar, 3 ms(-1) and 100% of power level. Finally, the optimized response was compared to the efficiency of a chemical cleaning with NaOH solution, with and without the use of ultrasound. By using NaOH, cleaning efficiency nearly triples, and it improves up to 25% by adding ultrasound. Copyright © 2013 Elsevier B.V. All rights reserved.

Automated nystagmus analysis. [on-line computer technique for eye data processing

NASA Technical Reports Server (NTRS)

Oman, C. M.; Allum, J. H. J.; Tole, J. R.; Young, L. R.

1973-01-01

Several methods have recently been used for on-line analysis of nystagmus: A digital computer program has been developed to accept sampled records of eye position, detect fast phase components, and output cumulative slow phase position, continuous slow phase velocity, instantaneous fast phase frequency, and other parameters. The slow phase velocity is obtained by differentiation of the calculated cumulative position rather than the original eye movement record. Also, a prototype analog device has been devised which calculates the velocity of the slow phase component during caloric testing. Examples of clinical and research eye movement records analyzed with these devices are shown.

Influence of operating conditions on ceramic ultrafiltration membrane performance when treating textile effluents.

PubMed

Barredo-Damas, S; Alcaina-Miranda, M I; Gemma, M; Iborra-Clar, M I; Mendoza-Roca, J A

2011-01-01

This work studies the performance of three commercial ceramic ultrafiltration membranes (ZrO(2)-TiO(2)) treating raw effluent from a textile industry. The effect of crossflow velocity at 3, 4 and 5 m s(-1) as well as membrane characteristics, such as molecular weight cut-off (30, 50 and 150 kDa), on process performance were studied. Experiments were carried out in concentration mode in order to observe the effect of volume reduction factor simultaneously. Results showed a combined influence of both crossflow velocity and molecular weight cut-off on flux performance. TOC and COD removals up to 70% and 84% respectively were reached. On the other hand, almost complete color (>97%) and turbidity (>99%) removals were achieved for all the membranes and operating conditions.

Method for concentration and separation of biological organisms by ultrafiltration and dielectrophoresis

DOEpatents

Simmons, Blake A.; Hill, Vincent R.; Fintschenko, Yolanda; Cummings, Eric B.

2012-09-04

Disclosed is a method for monitoring sources of public water supply for a variety of pathogens by using a combination of ultrafiltration techniques together dielectrophoretic separation techniques. Because water-borne pathogens, whether present due to "natural" contamination or intentional introduction, would likely be present in drinking water at low concentrations when samples are collected for monitoring or outbreak investigations, an approach is needed to quickly and efficiently concentrate and separate particles such as viruses, bacteria, and parasites in large volumes of water (e.g., 100 L or more) while simultaneously reducing the sample volume to levels sufficient for detecting low concentrations of microbes (e.g., <10 mL). The technique is also designed to screen the separated microbes based on specific conductivity and size.

Quantification of Free Phenytoin by Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS).

PubMed

Peat, Judy; Frazee, Clint; Garg, Uttam

2016-01-01

Phenytoin (diphenylhydantoin) is an anticonvulsant drug that has been used for decades for the treatment of many types of seizures. The drug is highly protein bound and measurement of free-active form of the drug is warranted particularly in patients with conditions that can affect drug protein binding. Here, we describe a LC/MS/MS method for the measurement of free phenytoin. Free drug is separated by ultrafiltration of serum or plasma. Ultrafiltrate is treated with acetonitrile containing internal standard phenytoin d-10 to precipitate proteins. The mixture is centrifuged and supernatant is injected onto LC-MS-MS, and analyzed using multiple reaction monitoring. This method is linear from 0.1 to 4.0 μg/mL and does not demonstrate any significant ion suppression or enhancement.

Flower Power: Sunflowers as a Model for Logistic Growth

ERIC Educational Resources Information Center

Fernandez, Eileen; Geist, Kristi A.

2011-01-01

Logistic growth displays an interesting pattern: It starts fast, exhibiting the rapid growth characteristic of exponential models. As time passes, it slows in response to constraints such as limited resources or reallocation of energy. The growth continues to slow until it reaches a limit, called capacity. When the growth describes a population,…

Revealing the cascade of slow transients behind a large slow slip event

NASA Astrophysics Data System (ADS)

Frank, W.; Rousset, B.; Lasserre, C.; Campillo, M.

2017-12-01

Capable of reaching similar magnitudes to large megathrust earthquakes (Mw > 7), slow slip events play a major role in accommodating tectonic motion on plate boundaries. These slip transients are the slow release of built-up tectonic stress that are geodetically imaged as a predominantly aseismic rupture, which is smooth in both time and space. We demonstrate here that large slow slip events are in fact a complex cascade of short-duration slow transients. Using a dense catalog of low-frequency earthquakes as a guide, we investigate the Mw 7.5 slow slip event that occurred in 2006 along the subduction interface 40 km beneath Guerrero, Mexico. We show that while the long-period surface displacement as recorded by GPS suggests a six month duration, motion in the direction of tectonic release only sporadically occurs over 55 days and its surface signature is attenuated by rapid relocking of the plate interface. These results demonstrate that our current conceptual model of slow and continuous rupture is an artifact of low-resolution geodetic observations of a superposition of small, clustered slip events. Our proposed description of slow slip as a cascade of slow transients implies that we systematically overestimate the duration T and underestimate the moment magnitude M of large slow slip events.

Fractional dynamics of globally slow transcription and its impact on deterministic genetic oscillation.

PubMed

Wei, Kun; Gao, Shilong; Zhong, Suchuan; Ma, Hong

2012-01-01

In dynamical systems theory, a system which can be described by differential equations is called a continuous dynamical system. In studies on genetic oscillation, most deterministic models at early stage are usually built on ordinary differential equations (ODE). Therefore, gene transcription which is a vital part in genetic oscillation is presupposed to be a continuous dynamical system by default. However, recent studies argued that discontinuous transcription might be more common than continuous transcription. In this paper, by appending the inserted silent interval lying between two neighboring transcriptional events to the end of the preceding event, we established that the running time for an intact transcriptional event increases and gene transcription thus shows slow dynamics. By globally replacing the original time increment for each state increment by a larger one, we introduced fractional differential equations (FDE) to describe such globally slow transcription. The impact of fractionization on genetic oscillation was then studied in two early stage models--the Goodwin oscillator and the Rössler oscillator. By constructing a "dual memory" oscillator--the fractional delay Goodwin oscillator, we suggested that four general requirements for generating genetic oscillation should be revised to be negative feedback, sufficient nonlinearity, sufficient memory and proper balancing of timescale. The numerical study of the fractional Rössler oscillator implied that the globally slow transcription tends to lower the chance of a coupled or more complex nonlinear genetic oscillatory system behaving chaotically.

WATER QUALITY

EPA Science Inventory

This manual was develped to provide an overview of microfiltration and ultrafiltration technology for operators, administrators, engineers, scientists, educators, and anyone seeking an introduction to these processes. Chapters on theory, water quality, applications, design, equip...

Anomalous versus slowed-down Brownian diffusion in the ligand-binding equilibrium.

PubMed

Soula, Hédi; Caré, Bertrand; Beslon, Guillaume; Berry, Hugues

2013-11-05

Measurements of protein motion in living cells and membranes consistently report transient anomalous diffusion (subdiffusion) that converges back to a Brownian motion with reduced diffusion coefficient at long times after the anomalous diffusion regime. Therefore, slowed-down Brownian motion could be considered the macroscopic limit of transient anomalous diffusion. On the other hand, membranes are also heterogeneous media in which Brownian motion may be locally slowed down due to variations in lipid composition. Here, we investigate whether both situations lead to a similar behavior for the reversible ligand-binding reaction in two dimensions. We compare the (long-time) equilibrium properties obtained with transient anomalous diffusion due to obstacle hindrance or power-law-distributed residence times (continuous-time random walks) to those obtained with space-dependent slowed-down Brownian motion. Using theoretical arguments and Monte Carlo simulations, we show that these three scenarios have distinctive effects on the apparent affinity of the reaction. Whereas continuous-time random walks decrease the apparent affinity of the reaction, locally slowed-down Brownian motion and local hindrance by obstacles both improve it. However, only in the case of slowed-down Brownian motion is the affinity maximal when the slowdown is restricted to a subregion of the available space. Hence, even at long times (equilibrium), these processes are different and exhibit irreconcilable behaviors when the area fraction of reduced mobility changes. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Vascular endothelial growth factor receptor-3 is a novel target to improve net ultrafiltration in methylglyoxal-induced peritoneal injury.

PubMed

Terabayashi, Takeshi; Ito, Yasuhiko; Mizuno, Masashi; Suzuki, Yasuhiro; Kinashi, Hiroshi; Sakata, Fumiko; Tomita, Takako; Iguchi, Daiki; Tawada, Mitsuhiro; Nishio, Ryosuke; Maruyama, Shoichi; Imai, Enyu; Matsuo, Seiichi; Takei, Yoshifumi

2015-09-01

Appropriate fluid balance is important for good clinical outcomes and survival in patients on peritoneal dialysis. We recently reported that lymphangiogenesis associated with fibrosis developed in the peritoneal cavity via the transforming growth factor-β1-vascular endothelial growth factor-C (VEGF-C) pathway. We investigated whether VEGF receptor-3 (VEGFR-3), the receptor for VEGF-C and -D, might be a new target to improve net ultrafiltration by using adenovirus-expressing soluble VEGFR-3 (Adeno-sVEGFR-3) in rodent models of peritoneal injury induced by methylglyoxal (MGO). We demonstrated that lymphangiogenesis developed in these MGO models, especially in the diaphragm, indicating that lymphangiogenesis is a common feature in the peritoneal cavity with inflammation and fibrosis. In MGO models, VEGF-D was significantly increased in the diaphragm; however, VEGF-C was not significantly upregulated. Adeno-sVEGFR-3, which was detected on day 50 after administration via tail vein injections, successfully suppressed lymphangiogenesis in the diaphragm and parietal peritoneum in mouse MGO models without significant effects on fibrosis, inflammation, or neoangiogenesis. Drained volume in the peritoneal equilibration test using a 7.5% icodextrin peritoneal dialysis solution (the 7.5% icodextrin peritoneal equilibration test) was improved by Adeno-sVEGFR-3 on day 22 (P<0.05) and day 50 after reduction of inflammation (P<0.01), indicating that the 7.5% icodextrin peritoneal equilibration test identifies changes in lymphangiogenesis. The solute transport rate was not affected by suppression of lymphangiogenesis. In human peritoneal dialysis patients, the dialysate to plasma ratio of creatinine positively correlated with the dialysate VEGF-D concentration (P<0.001). VEGF-D mRNA was significantly higher in the peritoneal membranes of patients with ultrafiltration failure, indicating that VEGF-D is involved in the development of lymphangiogenesis in peritoneal dialysis patients. These results indicate that VEGFR-3 is a new target to improve net ultrafiltration by suppressing lymphatic absorption and that the 7.5% icodextrin peritoneal equilibration test is useful for estimation of lymphatic absorption.

[Effect of priming solution and ultrafiltration on post-operative bleeding and blood transfusion in cardiac surgery. Randomized controlled trial].

PubMed

Olmos Rodríguez, M; Ballester Hernández, J A; Arteta Bárcenas, M T; Rodríguez Cerezo, A; Vidarte Ortiz de Artiñano, M A; Veiga Alameda, C

2015-02-01

Assess the effectiveness of priming the extracorporeal circulation system with albumin-mannitol combined with ultrafiltration during extracorporeal circulation to reduce post-operative bleeding and transfusion requirements in heart surgery, as well as its impact on the fluid balance, coagulation and hematocrit parameters, re-operation for bleeding, ICU, and hospital length of stay. A total of 134 patients scheduled for heart surgery were randomized to receive Ringer's lactate 1,500mL in the priming reservoir (group C), or mannitol 20% 250mL, albumin 20% 150mL and Ringer's lactate 1,100mL combined with ultrafiltration (group T). Bleeding volume, transfusions, fluid balance, coagulation, and hematology parameters were determined until 48h in the post-operative period. There was a reduction of postoperative bleeding in group T, 1,165±789mL vs 992±662mL (P=.17), and red blood cell concentrate transfusions, 694±843mL vs 413±605mL (P=.03). Intra-operative and post-operative fluid balance was significantly less positive in group T, with an overall balance of 2,292±2,152mL vs 5,388±2,834mL (P<.001). There were higher values of hemoglobin and hematocrit, intraoperative (P<.001), on admission to ICU (P=.001), and at 6h (P=.05) in group T, and lower INR at 6h (P=.01) and 24h (P=.02). Re-operation rate and length of stay in ICU were higher in group C, but not statiscally significant. The priming of extracorporeal reservoir with mannitol, albumin, and Ringer's lactate, combined with ultrafiltration, significantly improves intra- and post-operative fluid balance, resulting in a reduction in blood transfusions, with no significant decrease in post-operative bleeding, re-operation bleeding rate, and length of stay in the ICU. Copyright © 2014 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

Effect of solvent and temperature on the size distribution of casein micelles measured by dynamic light scattering.

PubMed

Beliciu, C M; Moraru, C I

2009-05-01

The objectives of this study were to investigate the effect of the solvent on the accuracy of casein micelle particle size determination by dynamic light scattering (DLS) at different temperatures and to establish a clear protocol for these measurements. Dynamic light scattering analyses were performed at 6, 20, and 50 degrees C using a 90Plus Nanoparticle Size Analyzer (Brookhaven Instruments, Holtsville, NY). Raw and pasteurized skim milk were used as sources of casein micelles. Simulated milk ultrafiltrate, ultrafiltered water, and permeate obtained by ultrafiltration of skim milk using a 10-kDa cutoff membrane were used as solvents. The pH, ionic concentration, refractive index, and viscosity of all solvents were determined. The solvents were evaluated by DLS to ensure that they did not have a significant influence on the results of the particle size measurements. Experimental protocols were developed for accurate measurement of particle sizes in all solvents and experimental conditions. All measurements had good reproducibility, with coefficients of variation below 5%. Both the solvent and the temperature had a significant effect on the measured effective diameter of the casein micelles. When ultrafiltered permeate was used as a solvent, the particle size and polydispersity of casein micelles decreased as temperature increased. The effective diameter of casein micelles from raw skim milk diluted with ultrafiltered permeate was 176.4 +/- 5.3 nm at 6 degrees C, 177.4 +/- 1.9 nm at 20 degrees C, and 137.3 +/- 2.7 nm at 50 degrees C. This trend was justified by the increased strength of hydrophobic bonds with increasing temperature. Overall, the results of this study suggest that the most suitable solvent for the DLS analyses of casein micelles was casein-depleted ultrafiltered permeate. Dilution with water led to micelle dissociation, which significantly affected the DLS measurements, especially at 6 and 20 degrees C. Simulated milk ultrafiltrate seemed to give accurate results only at 20 degrees C. Results obtained in simulated milk ultrafiltrate at 6 degrees C could not be explained based on the known effects of temperature on the casein micelle, whereas at 50 degrees C, precipitation of amorphous calcium phosphate affected the DLS measurement.

THE HISTOLOGY OF FITC AND FITC-17B ESTRADIOL IN CUNNER, TAUTOGOLABRUS ADSPERSUS, AFTER SUBCUTANEOUS IMPLANTATION IN A CONTROLLED RELEASE MATRIX

EPA Science Inventory

To mimic environmental exposures in studying the effects of estrogenic chemicals on fish reproduction, a slow-release mechanism is needed to deliver a continuous dosing of chemicals over the course of a long-term study. The effects of slow-release chemical exposures via a subcuta...

Fast-slow asymptotics for a Markov chain model of fast sodium current

NASA Astrophysics Data System (ADS)

Starý, Tomáš; Biktashev, Vadim N.

2017-09-01

We explore the feasibility of using fast-slow asymptotics to eliminate the computational stiffness of discrete-state, continuous-time deterministic Markov chain models of ionic channels underlying cardiac excitability. We focus on a Markov chain model of fast sodium current, and investigate its asymptotic behaviour with respect to small parameters identified in different ways.

SITE TECHNOLOGY CAPSULE: ZENOGEM™ WASTEWATER TREATMENT PROCESS

EPA Science Inventory

Zenon Environmental System's ZenoGem™ Wastewater Treatment Process treats aqueous media contaminated with volatile/semi-volatile organic compounds. This technology combines aerobic biological treatment to remove biodegradable organic compounds with ultrafiltration to separate res...

21 CFR 177.2910 - Ultra-filtration membranes.

Code of Federal Regulations, 2012 CFR

2012-04-01

... a microporous poly(vinylidene fluoride) membrane with a hydrophilic surface modifier consisting of... washing with a minimum of 8 gallons of potable water prior to their first use in contact with food. (g...

21 CFR 177.2910 - Ultra-filtration membranes.

Code of Federal Regulations, 2011 CFR

2011-04-01

... a microporous poly(vinylidene fluoride) membrane with a hydrophilic surface modifier consisting of... washing with a minimum of 8 gallons of potable water prior to their first use in contact with food. (g...

21 CFR 177.2910 - Ultra-filtration membranes.

Code of Federal Regulations, 2013 CFR

2013-04-01

... a microporous poly(vinylidene fluoride) membrane with a hydrophilic surface modifier consisting of... washing with a minimum of 8 gallons of potable water prior to their first use in contact with food. (g...

Pretreatment Engineering Platform Phase 1 Final Test Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurath, Dean E.; Hanson, Brady D.; Minette, Michael J.

2009-12-23

Pacific Northwest National Laboratory (PNNL) was tasked by Bechtel National Inc. (BNI) on the River Protection Project, Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to conduct testing to demonstrate the performance of the WTP Pretreatment Facility (PTF) leaching and ultrafiltration processes at an engineering-scale. In addition to the demonstration, the testing was to address specific technical issues identified in Issue Response Plan for Implementation of External Flowsheet Review Team (EFRT) Recommendations - M12, Undemonstrated Leaching Processes.( ) Testing was conducted in a 1/4.5-scale mock-up of the PTF ultrafiltration system, the Pretreatment Engineering Platform (PEP). Parallel laboratory testing wasmore » conducted in various PNNL laboratories to allow direct comparison of process performance at an engineering-scale and a laboratory-scale. This report presents and discusses the results of those tests.« less

Effect of acid whey-fortified breads on caecal fermentation processes and blood lipid profile in rats.

PubMed

Wronkowska, Małgorzata; Soral-Śmietana, Maria; Zduńczyk, Zenon; Juśkiewicz, Jerzy; Jadacka, Monika; Majkowska, Anna; Dajnowiec, Fabian J

2017-08-01

Two types of diet - standard and atherogenic - were used to study the effect of wheat or wheat-rye breads supplemented with 20 % acid whey concentrate after ultrafiltration on the physiological response of growing rats. The acid whey concentrate after ultrafiltration used in rat diets caused reduced weight gain (for atherogenic diet with wheat bread); growth of caecum tissue and digesta weight; a decrease in the pH of caecum digesta (for atherogenic diet); reduced activity of bacterial glycolytic enzymes; and a significant increase in total SCFA for both types of diet with wheat-rye breads containing acid whey concentrate. For wheat bread with acid whey, in standard diet, a statistically significant increase was found in the population of bifidobacteria. The results showed that the acid whey concentrates could be used as a valuable food ingredient.

Polyethersulfone - barium chloride blend ultrafiltration membranes for dye removal studies

NASA Astrophysics Data System (ADS)

Rambabu, K.; Srivatsan, N.; Gurumoorthy, Anand V. P.

2017-11-01

A series of Polyethersulfone (PES) - barium chloride (BaCl2) blend ultra filtration membrane was developed by varying the BaCl2 concentration in the dope solution. Prepared membranes were subjected to membrane characterization and their performance was studied through dye rejection tests. Morphological studies through SEM and AFM showed that the composite membranes exhibited differences in morphologies, porosities and properties due to the BaCl2 addition as compared with pristine PES membrane. Addition of the inorganic modifier enhanced the hydrophilicity and water permeability of the blend membrane system. Polymer enhanced ultrafiltration of dye solutions showed that the proposed blend system had better performance in terms of flux and rejection efficiency than the pure polymer membrane. The performance of the 2 wt% BaCl2 blend membrane was more promising for application to real time dye wastewater studies.

Synthesis and characterization of composite polysulfone membranes for desalination in nanofiltration technique.

PubMed

Akbari, A; Homayonfal, M; Jabbari, V

2010-01-01

Composite nanofiltration (NF) membrane was developed polyacrylic acid (PAA) in situ UV graft polymerization process using ultrafiltration (UF) polysulfone (PSF) membrane as porous support. FT-IR spectra indicated that grafting was performed and it show peaks at 1,732 cm⁻¹ and 3,396 cm⁻¹ region for CO and OH starching bond of acrylic acid (AA) monomer, respectively. AFM microscopy showed the roughness of surface was reduced by increase of UV irradiation times. Effect of irradiation time on the grafting of acrylic acid (AA) in the same concentration was discussed. The salts rejection increase was accompanied with grafting of polysulfone (PSF) ultrafiltration (UF) membrane. The rejection of Na₂SO₄, MgSO₄, NaCl and CaCl₂ salts by PSF-grafted-PAA nanofiltration (NF) membrane was in 98, 60, 52 and 30% respectively, under 0.3 MPa.

Treatment of the Bleaching Effluent from Sulfite Pulp Production by Ceramic Membrane Filtration

PubMed Central

Ebrahimi, Mehrdad; Busse, Nadine; Kerker, Steffen; Schmitz, Oliver; Hilpert, Markus; Czermak, Peter

2015-01-01

Pulp and paper waste water is one of the major sources of industrial water pollution. This study tested the suitability of ceramic tubular membrane technology as an alternative to conventional waste water treatment in the pulp and paper industry. In this context, in series batch and semi-batch membrane processes comprising microfiltration, ultrafiltration and nanofiltration, ceramic membranes were developed to reduce the chemical oxygen demand (COD) and remove residual lignin from the effluent flow during sulfite pulp production. A comparison of the ceramic membranes in terms of separation efficiency and performance revealed that the two-stage process configuration with microfiltration followed by ultrafiltration was most suitable for the efficient treatment of the alkaline bleaching effluent tested herein, reducing the COD concentration and residual lignin levels by more than 35% and 70%, respectively. PMID:26729180

Treatment of the Bleaching Effluent from Sulfite Pulp Production by Ceramic Membrane Filtration.

PubMed

Ebrahimi, Mehrdad; Busse, Nadine; Kerker, Steffen; Schmitz, Oliver; Hilpert, Markus; Czermak, Peter

2015-12-31

Pulp and paper waste water is one of the major sources of industrial water pollution. This study tested the suitability of ceramic tubular membrane technology as an alternative to conventional waste water treatment in the pulp and paper industry. In this context, in series batch and semi-batch membrane processes comprising microfiltration, ultrafiltration and nanofiltration, ceramic membranes were developed to reduce the chemical oxygen demand (COD) and remove residual lignin from the effluent flow during sulfite pulp production. A comparison of the ceramic membranes in terms of separation efficiency and performance revealed that the two-stage process configuration with microfiltration followed by ultrafiltration was most suitable for the efficient treatment of the alkaline bleaching effluent tested herein, reducing the COD concentration and residual lignin levels by more than 35% and 70%, respectively.

Reduction of disinfection by-product precursors in reservoir water by coagulation and ultrafiltration.

PubMed

Wang, Feng; Gao, Baoyu; Ma, Defang; Yue, Qinyan; Li, Ruihua; Wang, Qianwen

2016-11-01

In this study, reservoir water intended for drinking water supply was treated by (i) ultrafiltration (UF) (ii) coagulation (CW) (iii) coagulation combined with ultrafiltration (CW-UF). To probe the influences of three treatment processes on disinfection byproduct (DBP) precursors in source water, the changes of dissolved organic matter (DOM) amounts and physicochemical properties, and disinfection byproduct (DBP) formation characteristics during chlorine disinfection were investigated. Both carbonaceous DBP (C-DBP) and nitrogenous DBP (N-DBP) formation and speciation were analyzed. The influence of chlorine dose, contact time on DBP formation and speciation were also studied to optimize the disinfection conditions to minimize the DBP formation. Compared with UF and CW alone, CW-UF improved the dissolved organic carbon (DOC) removal from about 20 % to 59 %. The three-dimensional excitation and emission matrix (3DEEM) fluorescence spectroscopy analysis showed that CW-UF had high removal efficiency in microbial products (Region IV), fulvic acid-like (Region III) and humic acid-like (Region V). The total C-DBP was determined by the formation of trihalomethanes and trichloromethane was the most abundant species (40 %). The most abundant N-DBP species was dichloroacetonitrile (32.5 %), followed by trichloroactetonitrile. CW-UF effectively reduced the risk of DBPs in drinking water supply by reducing 30.8 % and 16.9 % DBPs formation potential compared with UF and CW alone. Increasing contact time improved the yields of both C-DBPs and N-DBPs. Chlorine dosage had slight influence on DBP yield in this study.

Selective separation of Eu{sup 3+} using polymer-enhanced ultrafiltration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Norton, M.V.

1994-03-01

A process to selectively remove {sup 241}Am from liquid radioactive waste was investigated as an actinide separation method applicable to Hanford and other waste sites. The experimental procedures involved removal of Eu, a nonradioactive surrogate for Am, from aqueous solutions at pH 5 using organic polymers in conjunction with ultrafiltration. Commercially available polyacrylic acid (60,000 MW) and Pacific Northwest Laboratory`s (PNL) synthesized E3 copolymer ({approximately}10,000 MW) were tested. Test solutions containing 10 {mu}g/mL of Eu were dosed vath each polymer at various concentrations in order to bind Eu (i.e., by complexation and/or cation exchange) for subsequent rejection by an ultrafiltrationmore » coupon. Test solutions were filtered with and without polymer to determine if enhanced Eu separation could be achieved from polymer treatment. Both polymers significantly increased Eu removal. Optimum concentrations were 20 {mu}g/mL of polyacrylic acid and 100 {mu}g/mL of E3 for 100% Eu rejection by the Amicon PM10 membrane at 55 psi. In addition to enhancement of removal, the polymers selectively bound Eu over Na, suggesting that selective separation of Eu was possible. This suggests that polymer-enhanced ultrafiltration is a potential process for separation of {sup 241}Am from Hanford tank waste, further investigation of binding agents and membranes effective under very alkaline and high ionic strength is warranted. This process also has potential applications for selective separation of toxic metals from industrial process streams.« less

Concentrating membrane proteins using ultrafiltration without concentrating detergents.

PubMed

Feroz, Hasin; Vandervelden, Craig; Ikwuagwu, Bon; Ferlez, Bryan; Baker, Carol S; Lugar, Daniel J; Grzelakowski, Mariusz; Golbeck, John H; Zydney, Andrew L; Kumar, Manish

2016-10-01

Membrane proteins (MPs) are of rapidly growing interest in the design of pharmaceutical products, novel sensors, and synthetic membranes. Ultrafiltration (UF) using commercially available centrifugal concentrators is typically employed for laboratory-scale concentration of low-yield MPs, but its use is accompanied by a concomitant increase in concentration of detergent micelles. We present a detailed analysis of the hydrodynamic processes that control detergent passage during ultrafiltration of MPs and propose methods to optimize detergent passage during protein concentration in larger-scale membrane processes. Experiments were conducted using nonionic detergents, octyl-β-D glucoside (OG), and decyl-β-D maltoside (DM) with the bacterial water channel protein, Aquaporin Z (AqpZ) and the light driven chloride pump, halorhodopsin (HR), respectively. The observed sieving coefficient (So ), a measure of detergent passage, was evaluated in both stirred cell and centrifugal systems. So for DM and OG increased with increasing filtrate flux and decreasing shear rates in the stirred cell, that is, with increasing concentration polarization (CP). Similar effects were observed during filtration of MP-detergent (MPD) micelles. However, lower transmission was observed in the centrifugal system for both detergent and MPD systems. This is attributed to free convection-induced shear and hence reduced CP along the membrane surface during centrifugal UF. Thus to concentrate MPs without retention of detergent, design of UF systems that promote CP is required. Biotechnol. Bioeng. 2016;113: 2122-2130. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Dual-Functional Ultrafiltration Membrane for Simultaneous Removal of Multiple Pollutants with High Performance.

PubMed

Pan, Shunlong; Li, Jiansheng; Noonan, Owen; Fang, Xiaofeng; Wan, Gaojie; Yu, Chengzhong; Wang, Lianjun

2017-05-02

Simultaneous removal of multiple pollutants from aqueous solution with less energy consumption is crucial in water purification. Here, a novel concept of dual-functional ultrafiltration (DFUF) membrane is demonstrated by entrapment of nanostructured adsorbents into the finger-like pores of ultrafiltration (UF) membrane rather than in the membrane matrix in previous reports of blend membranes, resulting in an exceptionally high active content and simultaneous removal of multiple pollutants from water due to the dual functions of rejection and adsorption. As a demonstration, hollow porous Zr(OH) x nanospheres (HPZNs) were immobilized in poly(ether sulfone) (PES) UF membranes through polydopamine coating with a high content of 68.9 wt %. The decontamination capacity of DFUF membranes toward multiple model pollutants (colloidal gold, polyethylene glycol (PEG), Pb(II)) was evaluated against a blend membrane. Compared to the blend membrane, the DFUF membranes showed 2.1-fold increase in the effective treatment volume for the treatment of Pb(II) contaminated water from 100 ppb to below 10 ppb (WHO drinking water standard). Simultaneously, the DFUF membranes effectively removed the colloidal gold and PEG below instrument detection limit, however the blend membrane only achieved 97.6% and 96.8% rejection for colloidal gold and PEG, respectively. Moreover, the DFUF membranes showed negligible leakage of nanoadsorbents during testing; and the membrane can be easily regenerated and reused. This study sheds new light on the design of high performance multifunction membranes for drinking water purification.

Fractionation of canine serum magnesium.

PubMed

Schenck, Patricia A

2005-06-01

Serum total magnesium (tMg) consists of 3 fractions: ionized magnesium (iMg), protein-bound magnesium (pbMg), and complexed magnesium (cMg). Serum iMg may be measured by an ion-selective electrode, but determination of pbMg and cMg has not been attempted in dogs. The objectives of this study were to assess the validity of a micropartition system to fractionate serum tMg and to establish reference intervals for pbMg, cMg, and iMg in clinically normal dogs using this method. Serum samples from 10 clinically healthy dogs were fractionated using a micropartition system (Centrifree YM-30, Amicon Corp, Lexington, MA, USA). Serum tMg and iMg were measured in whole serum, and tMg was also measured in the ultrafiltrate. Concentration of cMg was obtained by the subtraction of iMg from tMg concentrations of the ultrafiltrate. Protein-bound Mg was calculated by subtracting the tMg concentration of the ultrafiltrate from the tMg concentration of whole serum. Results for pbMg and cMg using the micropartition system showed good reproducibility. Determination of tMg and iMg had acceptable inter- and intra-assay precision. Concentrations of iMg, cMg, and pbMg were 0.50 +/- 0.05 mmol/L, 0.05 +/- 0.04 mmol/L, and 0.24 +/- 0.04 mmol/L, representing 63%, 6%, and 31% of the tMg concentration, respectively. The micropartition system was a reproducible means to accurately assess cMg and pbMg concentrations in dogs.

Gold nanoparticle chemiresistors operating in biological fluids.

PubMed

Hubble, Lee J; Chow, Edith; Cooper, James S; Webster, Melissa; Müller, Karl-Heinz; Wieczorek, Lech; Raguse, Burkhard

2012-09-07

Functionalised gold nanoparticle (Au(NP)) chemiresistors are investigated for direct sensing of small organic molecules in biological fluids. The principle reason that Au(NP) chemiresistors, and many other sensing devices, have limited operation in biological fluids is due to protein and lipid fouling deactivating the sensing mechanism. In order to extend the capability of such chemiresistor sensors to operate directly in biofluids, it is essential to minimise undesirable matrix effects due to protein and lipidic components. Ultrafiltration membranes were investigated as semi-permeable size-selective barriers to prevent large biomolecule interactions with Au(NP) chemiresistors operating in protein-loaded biofluids. All of the ultrafiltration membranes protected the Au(NP) chemiresistors from fouling by the globular biomolecules, with the 10 kDa molecular weight cut-off size being optimum for operation in biofluids. Titrations of toluene in different protein-loaded fluids indicated that small molecule detection was possible. A sensor array consisting of six different thiolate-functionalised Au(NP) chemiresistors protected with a size-selective ultrafiltration membrane successfully identified, and discriminated the spoilage of pasteurised bovine milk. This proof-of-principle study demonstrates the on-chip protein separation and small metabolite detection capability, illustrating the potential for this technology in the field of microbial metabolomics. Overall, these results demonstrate that a sensor array can be protected from protein fouling with the use of a membrane, significantly increasing the possible application areas of Au(NP) chemiresistors ranging from the food industry to health services.

Pharmacokinetic analysis of flomoxef in children undergoing cardiopulmonary bypass and modified ultrafiltration.

PubMed

Masuda, Zenichi; Kurosaki, Yuji; Ishino, Kozo; Yamauchi, Keita; Sano, Shunji

2008-04-01

Cardiopulmonary bypass (CPB) induces changes in the pharmacokinetics of drugs. The purpose of this study was to model the pharmacokinetics of flomoxef, a cephalosporin antibiotic, in pediatric cardiac surgery. Each patient received a flomoxef dose of 30 mg/kg as a bolus after the induction of anesthesia and an additional dose (1 g for a child weighing < 10 kg, 2 g for > or = 10 kg) was injected into the CPB prime. Modified ultrafiltration (MUF) was routinely performed. Blood samples, urine, and ultrafiltrate were collected. In seven patients (group I), serum flomoxef concentration-time courses were analyzed by a modified two-compartment model. Utilizing the estimated parameters, serum concentrations were simulated in another eight patients (group II). The initiation of CPB resulted in an abrupt increase in serum flomoxef concentrations in group I; however, concentrations declined biexponentially. The amount of excreted flomoxef in the urine and by MUF was 47% +/- 8% of the total administered dose. In group II, an excellent fit was found between the values calculated by the program and the observed serum concentrations expressed; most of the performance errors were <1.0. There was no difference in any kinetic parameter between group I and groups I + II (n = 15). The pharmacokinetics of flomoxef in children undergoing CPB and MUF were well fitted to a modified two-compartment model. Using the kinetic data from this study, the individualization of dosage regimens for prophylactic use of flomoxef might be possible.

Ultrafiltration technology with a ceramic membrane for reactive dye removal: optimization of membrane performance.

PubMed

Alventosa-deLara, E; Barredo-Damas, S; Alcaina-Miranda, M I; Iborra-Clar, M I

2012-03-30

An ultrafiltration (UF) ceramic membrane was used to decolorize Reactive Black 5 (RB5) solutions at different dye concentrations (50 and 500 mg/L). Transmembrane pressure (TMP) and cross-flow velocity (CFV) were modified to study their influence on initial and steady-state permeate flux (J(p)) and dye rejection (R). Generally, J(p) increased with higher TMP and CFV and lower feed concentration, up to a maximum steady-state J(p) of 266.81 L/(m(2)h), obtained at 3 bar, 3m/s and 50mg/L. However, there was a TMP value (which changed depending on operating CFV and concentration) beyond which slight or no further increase in steady-state J(p) was observed. Similarly, the higher the CFV was, the more slightly the steady-state J(p) increased. Furthermore, the effectiveness of ultrafiltration treatment was evaluated through dye rejection coefficient. The results showed significant dye removals, regardless of the tested conditions, with steady-state R higher than 79.8% for the 50mg/L runs and around 73.2% for the 500 mg/L runs. Finally response surface methodology (RSM) was used to optimize membrane performance. At 50mg/L, a TMP of 4 bar and a CFV of 2.53 m/s were found to be the conditions giving the highest steady-state J(p), 255.86 L/(m(2)h), and the highest R, 95.2% simultaneously. Copyright © 2012 Elsevier B.V. All rights reserved.

Current advances in screening for bioactive components from medicinal plants by affinity ultrafiltration mass spectrometry.

PubMed

Chen, Guilin; Huang, Bill X; Guo, Mingquan

2018-05-21

Medicinal plants have played an important role in maintaining human health for thousands of years. However, the interactions between the active components in medicinal plants and some certain biological targets during a disease are still unclear in most cases. To conduct the high-throughput screening for small active molecules that can interact with biological targets, which is of great theoretical significance and practical value. The ultrafiltration mass spectrometry (UF-LC/MS) is a powerful bio-analytical method by combining affinity ultrafiltration and liquid chromatography-mass spectrometry (LC/MS), which could rapidly screen and identify small active molecules that bind to biological targets of interest at the same time. Compared with other analytical methods, affinity UF-LC/MS has the characteristics of fast, sensitive and high throughput, and is especially suitable for the complicated extracts of medicinal plants. In this review, the basic principle, characteristics and some most recent challenges in UF-LC/MS have been demonstrated. Meanwhile, the progress and applications of affinity UF-LC/MS in the discovery of the active components from natural medicinal plants and the interactions between small molecules and biological target proteins are also briefly summarised. In addition, the future directions for UF-LC/MS are also prospected. Affinity UF-LC/MS is a powerful tool in studies on the interactions between small active molecules and biological protein targets, especially in the high-throughput screening of active components from the natural medicinal plants. Copyright © 2018 John Wiley & Sons, Ltd.

Production of wheat gluten hydrolysates with reduced antigenicity employing enzymatic hydrolysis combined with downstream unit operations.

PubMed

Merz, Michael; Kettner, Lucas; Langolf, Emma; Appel, Daniel; Blank, Imre; Stressler, Timo; Fischer, Lutz

2016-08-01

Due to allergies or other health disorders a certain segment of the population is not able to safely consume some plant proteins, which are the main protein support in human nutrition. Coeliac disease is a prominent autoimmune disorder and requires a strict adherence to a gluten-free diet. The aim of this study was to identify suitable combinations of enzymatic hydrolysis and common unit operations in food processing (centrifugation, ultra-filtration) to produce gluten-free wheat gluten hydrolysates for food application. To analyse the hydrolysates, a simple and cheap competitive ELISA protocol was designed and validated in this study as well. The competitive ELISA was validated using gliadin spiked skim milk protein hydrolysates, due to the latter application of the assay. The limit of quantification was 4.19 mg kg(-1) , which allowed the identification of gluten-free (<20 mg kg(-1) ) hydrolysates. Enzymatic hydrolysis, including the type of peptidase, and the downstream processing greatly affected the antigenicity of the hydrolysates. Enzymatic hydrolysis and downstream processing operations, such as centrifugation and ultra-filtration, reduced the antigenicity of wheat gluten hydrolysates. Gluten-free hydrolysates were obtained with Flavourzyme after centrifugation (25 g L(-1) substrate) and after 1 kDa ultra-filtration (100 g L(-1) substrate). A multiple peptidase complex, such as Flavourzyme, seems to be required for the production of gluten-free hydrolysates. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Tangential Flow Ultrafiltration Allows Purification and Concentration of Lauric Acid-/Albumin-Coated Particles for Improved Magnetic Treatment.

PubMed

Zaloga, Jan; Stapf, Marcus; Nowak, Johannes; Pöttler, Marina; Friedrich, Ralf P; Tietze, Rainer; Lyer, Stefan; Lee, Geoffrey; Odenbach, Stefan; Hilger, Ingrid; Alexiou, Christoph

2015-08-14

Superparamagnetic iron oxide nanoparticles (SPIONs) are frequently used for drug targeting, hyperthermia and other biomedical purposes. Recently, we have reported the synthesis of lauric acid-/albumin-coated iron oxide nanoparticles SEON(LA-BSA), which were synthesized using excess albumin. For optimization of magnetic treatment applications, SPION suspensions need to be purified of excess surfactant and concentrated. Conventional methods for the purification and concentration of such ferrofluids often involve high shear stress and low purification rates for macromolecules, like albumin. In this work, removal of albumin by low shear stress tangential ultrafiltration and its influence on SEON(LA-BSA) particles was studied. Hydrodynamic size, surface properties and, consequently, colloidal stability of the nanoparticles remained unchanged by filtration or concentration up to four-fold (v/v). Thereby, the saturation magnetization of the suspension can be increased from 446.5 A/m up to 1667.9 A/m. In vitro analysis revealed that cellular uptake of SEON(LA-BSA) changed only marginally. The specific absorption rate (SAR) was not greatly affected by concentration. In contrast, the maximum temperature Tmax in magnetic hyperthermia is greatly enhanced from 44.4 °C up to 64.9 °C by the concentration of the particles up to 16.9 mg/mL total iron. Taken together, tangential ultrafiltration is feasible for purifying and concentrating complex hybrid coated SPION suspensions without negatively influencing specific particle characteristics. This enhances their potential for magnetic treatment.

Continuous ambulatory peritoneal dialysis (CAPD): experience with the first 100 patients in a Hong Kong centre.

PubMed

Chan, M K; Lam, S S; Chan, P C; Cheng, I K

1987-03-01

We treated 100 Chinese patients age 16 to 83 years by CAPD, using three 2-litre exchanges per day. The treatment was self-financed in 69 patients, by charitable organisations in 25 patients, and by government funds in 6 patients. Satisfactory biochemistry was maintained and there was no gross hyperlipidaemia, renal osteodystrophy, or loss of ultrafiltration capacity of the peritoneum. Rehabilitation was good and 62% of patients returned to full-time employment. The average duration of hospitalization was 11.3 days per patient year. Peritonitis usually due to Staphylococcus pyogenes occurred at a frequency of one episode per 12.3 patient-months. Sixteen patients were transplanted and had a 2-year graft survival of 78.5%. The cumulative patient survival was 97% at 1 year and 84% at 2 years. The corresponding technique survival rates were 87% and 76% respectively.

Anti-bacterial properties of ultrafiltration membrane modified by graphene oxide with nano-silver particles.

PubMed

Li, Jingchun; Liu, Xuyang; Lu, Jiaqi; Wang, Yudan; Li, Guanglu; Zhao, Fangbo

2016-12-15

To improve the anti-biofouling properties of PVDF membranes, GO-Ag composites were synthesized and used as membrane antibacterial agent by a simple and environmentally friendly method. As identified by XRD, TEM and FTIR analysis, AgNPs were uniformly assembled on the synthesized GO-Ag sheets. The membranes were prepared by phase inversion method with different additional amounts (0.00-0.15wt%) of GO-Ag composites. The GO-Ag composites modified membranes show improved hydrophilicity, mechanical property and permeability than unmodified PVDF membrane. Specially, the antibacterial properties and inhibition of biofilm formation were greatly enhanced based on conventional inhibition zone test and anti-adhesion of bacterial experiment. The modified membranes also reveal a remarkable long-term continuous antimicrobial activity with slower release rate of Ag + compared to AgNPs/PVDF membrane. Copyright © 2016 Elsevier Inc. All rights reserved.

Poor ultrafiltration during nighttime dialysis in CAPD patients and its effects on fluid balance.

PubMed

Pagé, D E; Levine, D Z

1993-01-01

To evaluate fluid retention during the long nighttime peritoneal dwell in continuous ambulatory peritoneal dialysis (CAPD) patients, we measured remaining volumes in 70 patients. In only 50% of these patients were more than 2 L of fluid recovered; in 30% between 1.5 and 2 L were recovered; and in 17% of patients we retrieved less than 1.5 L of peritoneal fluid. In 3 of these patients, who were edematous and had marked pitting edema, we shortened the nighttime dwell by having the patients awaken after 4 hours and drain the dwell. This resulted in 3-5 kg of weight loss in each patient, when compared with each patient's previous use of long nighttime dwells. Finally, we propose in this report two automated methods whereby the period of nighttime dialysis can be controlled, while patients sleep, using a system of timer clamps.

Experimental demonstration of spinor slow light

NASA Astrophysics Data System (ADS)

Lee, Meng-Jung; Ruseckas, Julius; Lee, Chin-Yuan; Kudriašov, Viačeslav; Chang, Kao-Fang; Cho, Hung-Wen; JuzeliÅ«nas, Gediminas; Yu, Ite A.

2016-03-01

Over the last decade there has been a continuing interest in slow and stored light based on the electromagnetically induced transparency (EIT) effect, because of their potential applications in quantum information manipulation. However, previous experimental works all dealt with the single-component slow light which cannot be employed as a qubit. In this work, we report the first experimental demonstration of two-component or spinor slow light (SSL) using a double tripod (DT) atom-light coupling scheme. The oscillations between the two components, similar to the Rabi oscillation of a two-level system or a qubit, were observed. Single-photon SSL can be considered as two-color qubits. We experimentally demonstrated a possible application of the DT scheme as quantum memory and quantum rotator for the two-color qubits. This work opens up a new direction in the slow light research.

Controlling slow and fast light and dynamic pulse-splitting with tunable optical gain in a whispering-gallery-mode microcavity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asano, M.; Ikuta, R.; Imoto, N.

We report controllable manipulation of slow and fast light in a whispering-gallery-mode microtoroid resonator fabricated from Erbium (Er{sup 3+}) doped silica. We observe continuous transition of the coupling between the fiber-taper waveguide and the microresonator from undercoupling to critical coupling and then to overcoupling regimes by increasing the pump power even though the spatial distance between the resonator and the waveguide was kept fixed. This, in turn, enables switching from fast to slow light and vice versa just by increasing the optical gain. An enhancement of delay of two-fold over the passive silica resonator (no optical gain) was observed inmore » the slow light regime. Moreover, we show dynamic pulse splitting and its control in slow/fast light systems using optical gain.« less

Slow Earthquake Hunters: A New Citizen Science Project to Identify and Catalog Slow Slip Events in Geodetic Data

NASA Astrophysics Data System (ADS)

Bartlow, N. M.

2017-12-01

Slow Earthquake Hunters is a new citizen science project to detect, catalog, and monitor slow slip events. Slow slip events, also called "slow earthquakes", occur when faults slip too slowly to generate significant seismic radiation. They typically take between a few days and over a year to occur, and are most often found on subduction zone plate interfaces. While not dangerous in and of themselves, recent evidence suggests that monitoring slow slip events is important for earthquake hazards, as slow slip events have been known to trigger damaging "regular" earthquakes. Slow slip events, because they do not radiate seismically, are detected with a variety of methods, most commonly continuous geodetic Global Positioning System (GPS) stations. There is now a wealth of GPS data in some regions that experience slow slip events, but a reliable automated method to detect them in GPS data remains elusive. This project aims to recruit human users to view GPS time series data, with some post-processing to highlight slow slip signals, and flag slow slip events for further analysis by the scientific team. Slow Earthquake Hunters will begin with data from the Cascadia subduction zone, where geodetically detectable slow slip events with a duration of at least a few days recur at regular intervals. The project will then expand to other areas with slow slip events or other transient geodetic signals, including other subduction zones, and areas with strike-slip faults. This project has not yet rolled out to the public, and is in a beta testing phase. This presentation will show results from an initial pilot group of student participants at the University of Missouri, and solicit feedback for the future of Slow Earthquake Hunters.

Age-Dependency of Location of Epileptic Foci in "Continuous Spike-and-Waves during Sleep": A Parallel to the Posterior-Anterior Trajectory of Slow Wave Activity.

PubMed

Bölsterli Heinzle, Bigna Katrin; Bast, Thomas; Critelli, Hanne; Huber, Reto; Schmitt, Bernhard

2017-02-01

Epileptic encephalopathy with continuous spike-and-waves during sleep (CSWS) occurs during childhood and is characterized by an activation of spike wave complexes during slow wave sleep. The location of epileptic foci is variable, as is etiology. A relationship between the epileptic focus and age has been shown in various focal epilepsies following a posterior-anterior trajectory, and a link to brain maturation has been proposed. We hypothesize that in CSWS, maximal spike wave activity, corresponding to the epileptic focus, is related to age and shows a posterior-anterior evolution. In a retrospective cross-sectional study on CSWS (22 EEGs of 22 patients aged 3.1–13.5 years), the location of the epileptic focus is related to age and follows a posterior-anterior course. Younger patients are more likely to have posterior foci than older ones. We propose that the posterior-anterior trajectory of maximal spike waves in CSWS might reflect maturational changes of maximal expression of sleep slow waves, which follow a comparable course. Epileptic spike waves, that is, “hyper-synchronized slow waves” may occur at the place where the highest and therefore most synchronized slow waves meet brain tissue with an increased susceptibility to synchronization. Georg Thieme Verlag KG Stuttgart · New York.

Integration of auditory and kinesthetic information in motion: alterations in Parkinson's disease.

PubMed

Sabaté, Magdalena; Llanos, Catalina; Rodríguez, Manuel

2008-07-01

The main aim in this work was to study the interaction between auditory and kinesthetic stimuli and its influence on motion control. The study was performed on healthy subjects and patients with Parkinson's disease (PD). Thirty-five right-handed volunteers (young, PD, and age-matched healthy participants, and PD-patients) were studied with three different motor tasks (slow cyclic movements, fast cyclic movements, and slow continuous movements) and under the action of kinesthetic stimuli and sounds at different beat rates. The action of kinesthesia was evaluated by comparing real movements with virtual movements (movements imaged but not executed). The fast cyclic task was accelerated by kinesthetic but not by auditory stimuli. The slow cyclic task changed with the beat rate of sounds but not with kinesthetic stimuli. The slow continuous task showed an integrated response to both sensorial modalities. These data show that the influence of the multisensory integration on motion changes with the motor task and that some motor patterns are modulated by the simultaneous action of auditory and kinesthetic information, a cross-modal integration that was different in PD-patients. PsycINFO Database Record (c) 2008 APA, all rights reserved.

21 CFR 177.2910 - Ultra-filtration membranes.

Code of Federal Regulations, 2010 CFR

2010-04-01

... of a sintered carbon support that is coated with zirconium oxide (CAS Reg. No. 1314-23-4) containing... of an aluminum oxide support that is coated with zirconium oxide (CAS Reg. No. 1314-23-4) containing...

Topological Origins of the Slow Solar Wind

NASA Technical Reports Server (NTRS)

Antiochos, Spiro

2008-01-01

Although the slow solar wind has been studied for decades with both in situ and remote sensing observations, its origin is still a matter of intense debate. In the standard quasi-steady model, the slow wind is postulated to originate near coronal hole boundaries that define topologically well-behaved separatrices between open and closed field regions. In the interchange model, on the other hand, the slow wind is postulated to originate on open flux that is dynamically diffusing throughout the seemingly closed-field corona. We argue in favor of the quasi-steady scenario and propose that the slow wind is due to two effects: First, the open-closed boundary is highly complex due to the complexity of the photospheric flux distribution. Second, this boundary is continuously driven by the transport of magnetic helicity from the closed field region into the open. The implications of this model for the structure and dynamics of the corona and slow wind are discussed, and observational tests of the mode

A comparison of continuous video-EEG monitoring and 30-minute EEG in an ICU.

PubMed

Khan, Omar I; Azevedo, Christina J; Hartshorn, Alendia L; Montanye, Justin T; Gonzalez, Juan C; Natola, Mark A; Surgenor, Stephen D; Morse, Richard P; Nordgren, Richard E; Bujarski, Krzysztof A; Holmes, Gregory L; Jobst, Barbara C; Scott, Rod C; Thadani, Vijay M

2014-12-01

To determine whether there is added benefit in detecting electrographic abnormalities from 16-24 hours of continuous video-EEG in adult medical/surgical ICU patients, compared to a 30-minute EEG. This was a prospectively enroled non-randomized study of 130 consecutive ICU patients for whom EEG was requested. For 117 patients, a 30-minute EEG was requested for altered mental state and/or suspected seizures; 83 patients continued with continuous video-EEG for 16-24 hours and 34 patients had only the 30-minute EEG. For 13 patients with prior seizures, continuous video-EEG was requested and was carried out for 16-24 hours. We gathered EEG data prospectively, and reviewed the medical records retrospectively to assess the impact of continuous video-EEG. A total of 83 continuous video-EEG recordings were performed for 16-24 hours beyond 30 minutes of routine EEG. All were slow, and 34% showed epileptiform findings in the first 30 minutes, including 2% with seizures. Over 16-24 hours, 14% developed new or additional epileptiform abnormalities, including 6% with seizures. In 8%, treatment was changed based on continuous video-EEG. Among the 34 EEGs limited to 30 minutes, almost all were slow and 18% showed epileptiform activity, including 3% with seizures. Among the 13 patients with known seizures, continuous video-EEG was slow in all and 69% had epileptiform abnormalities in the first 30 minutes, including 31% with seizures. An additional 8% developed epileptiform abnormalities over 16-24 hours. In 46%, treatment was changed based on continuous video-EEG. This study indicates that if continuous video-EEG is not available, a 30-minute EEG in the ICU has a substantial diagnostic yield and will lead to the detection of the majority of epileptiform abnormalities. In a small percentage of patients, continuous video-EEG will lead to the detection of additional epileptiform abnormalities. In a sub-population, with a history of seizures prior to the initiation of EEG recording, the benefits of continuous video-EEG in monitoring seizure activity and influencing treatment may be greater.

Dynamics of a linear system coupled to a chain of light nonlinear oscillators analyzed through a continuous approximation

NASA Astrophysics Data System (ADS)

Charlemagne, S.; Ture Savadkoohi, A.; Lamarque, C.-H.

2018-07-01

The continuous approximation is used in this work to describe the dynamics of a nonlinear chain of light oscillators coupled to a linear main system. A general methodology is applied to an example where the chain has local nonlinear restoring forces. The slow invariant manifold is detected at fast time scale. At slow time scale, equilibrium and singular points are sought around this manifold in order to predict periodic regimes and strongly modulated responses of the system. Analytical predictions are in good accordance with numerical results and represent a potent tool for designing nonlinear chains for passive control purposes.

If slow rate of health care spending growth persists, projections may be off by $770 billion.

PubMed

Cutler, David M; Sahni, Nikhil R

2013-05-01

Despite earlier forecasts to the contrary, US health care spending growth has slowed in the past four years, continuing a trend that began in the early 2000s. In this article we attempt to identify why US health care spending growth has slowed, and we explore the spending implications if the trend continues for the next decade. We find that the 2007-09 recession, a one-time event, accounted for 37 percent of the slowdown between 2003 and 2012. A decline in private insurance coverage and cuts to some Medicare payment rates accounted for another 8 percent of the slowdown, leaving 55 percent of the spending slowdown unexplained. We conclude that a host of fundamental changes--including less rapid development of imaging technology and new pharmaceuticals, increased patient cost sharing, and greater provider efficiency--were responsible for the majority of the slowdown in spending growth. If these trends continue during 2013-22, public-sector health care spending will be as much as $770 billion less than predicted. Such lower levels of spending would have an enormous impact on the US economy and on government and household finances.

40 CFR 141.711 - Filtered system additional Cryptosporidium treatment requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced...(including softening) Direct filtration Slow sand or diatomaceous earth filtration Alternative filtration... survey or an equivalent source water assessment that after a system completed the monitoring conducted...

40 CFR 141.711 - Filtered system additional Cryptosporidium treatment requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced...(including softening) Direct filtration Slow sand or diatomaceous earth filtration Alternative filtration... survey or an equivalent source water assessment that after a system completed the monitoring conducted...

40 CFR 141.711 - Filtered system additional Cryptosporidium treatment requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced...(including softening) Direct filtration Slow sand or diatomaceous earth filtration Alternative filtration... survey or an equivalent source water assessment that after a system completed the monitoring conducted...

The S-Web Model for the Sources of the Slow Solar Wind

NASA Technical Reports Server (NTRS)

Antiochos, Spiro K.; Karpen, Judith T.; DeVore, C. Richard

2012-01-01

Models for the origin of the slow solar wind must account for two seemingly contradictory observations: The slow wind has the composition of the closed-field corona, implying that it originates from the continuous opening and closing of flux at the boundary between open and closed field. On the other hand, the slow wind has large angular width, up to 60 degrees, suggesting that its source extends far from the open-closed boundary. We describe a model that can explain both observations. The key idea is that the source of the slow wind at the Sun is a network of narrow (possibly singular) open-field corridors that map to a web of separatrices (the S-Web) and quasi-separatrix layers in the heliosphere. We discuss the dynamics of the S-Web model and its implications for present observations and for the upcoming observations from Solar Orbiter and Solar Probe Plus.

Chronic low-frequency stimulation transforms cat masticatory muscle fibers into jaw-slow fibers.

PubMed

Kang, Lucia H D; Hoh, Joseph F Y

2011-09-01

Cat masticatory muscle during regeneration expresses masticatory-specific myofibrillar proteins upon innervation by a fast muscle nerve but acquires the jaw-slow phenotype when innervated by a slow muscle nerve. Here, we test the hypothesis that chronic low-frequency stimulation simulating impulses from the slow nerve can result in masticatory-to-slow fiber-type transformation. In six cats, the temporalis muscle was continuously stimulated directly at 10 Hz for up to 12 weeks using a stimulator affixed to the skull. Stimulated muscles were analyzed by immunohistochemistry using, among others, monoclonal antibodies against masticatory-specific myosin heavy chain (MyHC), myosin binding protein-C, and tropomyosins. Under the electrodes, stimulation induced muscle regeneration, which generated slow fibers. Deep to the electrodes, at two to three weeks, two distinct populations of masticatory fibers began to express slow MyHC: 1) evenly distributed fibers that completely suppressed masticatory-specific proteins but transiently co-expressed fetal MyHCs, and 2) incompletely transformed fibers that express slow and masticatory but not fetal MyHCs. SDS-PAGE confirmed de novo expression of slow MyHC and β-tropomyosin in the stimulated muscles. We conclude that chronic low-frequency stimulation induces masticatory-to-slow fiber-type conversion. The two populations of transforming masticatory fibers may differ in their mode of activation or lineage of their myogenic cells.

Role of the sodium pump in pacemaker generation in dog colonic smooth muscle.

PubMed Central

Barajas-López, C; Chow, E; Den Hertog, A; Huizinga, J D

1989-01-01

1. The role of the Na+ pump in the generation of slow wave activity in circular muscle of the dog colon was investigated using a partitioned 'Abe-Tomita' type chamber for voltage control. 2. Blockade of the Na+ pump by omission of extracellular K+, by ouabain, or the combination of 0 mM-Na+ and ouabain, depolarized the membrane up to approximately -40 mV and abolished the slow wave activity. Repolarization back to the control membrane potential by hyperpolarizing current restored the slow wave activity. 3. Slow waves continued to be present in 0 Na+, Li+ HEPES solution. 4. The depolarization induced by the procedures to block Na+ pump activity was associated with an increase in input membrane resistance. 5. Voltage-current relationships show the presence of an inward rectification. 6. Reduction of temperature depolarized the membrane, and decreased the slow wave frequency and amplitude. The slow wave amplitude was restored by repolarization of the membrane. 7. Brief depolarizing pulses evoked premature slow waves. Brief hyperpolarizing pulses terminated the slow waves. 8. We conclude that abolition of slow wave activity by Na+ pump blockade is a direct effect of membrane depolarization and that the Na+ pump is not responsible for the generation of the slow wave. 9. Our results are consistent with the hypothesis that pacemaker activity in smooth muscle is a consequence of membrane conductance changes which are metabolically dependent. PMID:2607455

Continuous blood densitometry - Fluid shifts after graded hemorrhage in animals

NASA Technical Reports Server (NTRS)

Hinghofer-Szalkay, H.

1986-01-01

Rapid fluid shifts in four pigs and two dogs subjected to graded hemorrhage are investigated. Arterial blood density (BD), mean arterial pressure (MAP), central venous pressure (CVP), arterial plasma density (PD), hematocrit (Hct) and erythrocyte density were measured. The apparatus and mechancial oscillator technique for measuring density are described. Fluid shifts between red blood cells and blood plasma and alterations in the whole-body-to-large vessel Hct, F(cell) are studied using two models. The bases of the model calculations are discussed. A decrease in MAP, CVP, and BP is detected at the beginning of hemorrhaging; continued bleeding results in further BD decrease correlating with volume displacement. The data reveal that at 15 ml/kg blood loss the mean PD and BD dropped by 0.99 + or - 0.15 and 2.42 + or 0.26 g/liter, respectively, and the Hct dropped by 2.40 + or 0.47 units. The data reveal that inward-shifted fluid has a higher density than normal ultrafiltrate and/or there is a rise in the F(cell) ratio. It is noted that rapid fluid replacement ranged from 5.8 + or - 0.8 to 10.6 + or - 2.0 percent of the initial plasma volume.

Printing-assisted surface modifications of patterned ultrafiltration membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wardrip, Nathaniel C.; Dsouza, Melissa; Urgun-Demirtas, Meltem

Understanding and restricting microbial surface attachment will enhance wastewater treatment with membranes. We report a maskless lithographic patterning technique for the generation of patterned polymer coatings on ultrafiltration membranes. Polyethylene glycol, zwitterionic, or negatively charged hydrophilic polymer compositions in parallel- or perpendicular-striped patterns with respect to feed flow were evaluated using wastewater. Membrane fouling was dependent on the orientation and chemical composition of the coatings. Modifications reduced alpha diversity in the attached microbial community (Shannon indices decreased from 2.63 to 1.89) which nevertheless increased with filtration time. Sphingomonas species, which condition membrane surfaces and facilitate cellular adhesion, were depleted inmore » all modified membranes. Microbial community structure was significantly different between control, different patterns, and different chemistries. Lastly, this study broadens the tools for surface modification of membranes with polymer coatings and for understanding and optimization of antifouling surfaces.« less

Performance of ultrafiltration membrane process combined with coagulation/sedimentation.

PubMed

Jang, N Y; Watanabe, Y; Minegishi, S

2005-01-01

Effects of coagulation/sedimentation as a pre-treatment on the dead-end ultrafiltration (UF) membrane process were studied in terms of membrane fouling and removal efficiency of natural dissolved organic matter, using Chitose River water. Two types of experiment were carried out. One was a bench scale membrane filtration with jar-test and the other was membrane filtration pilot plant combined with the Jet Mixed Separator (JMS) as a pre-coagulation/sedimentation unit. In the bench scale experiment, the effects of coagulant dosage, pH and membrane operating pressure on the membrane fouling and removal efficiency of natural dissolved organic matter were investigated. In the pilot plant experiment, we also investigated the effect of pre-coagulation/sedimentation on the membrane fouling and the removal efficiency of natural dissolved organic matter. Coagulation/sedimentation prior to membrane filtration process controlled the membrane fouling and increased the removal efficiency of natural dissolved organic matter.

Printing-assisted surface modifications of patterned ultrafiltration membranes

DOE PAGES

Wardrip, Nathaniel C.; Dsouza, Melissa; Urgun-Demirtas, Meltem; ...

2016-10-17

Understanding and restricting microbial surface attachment will enhance wastewater treatment with membranes. We report a maskless lithographic patterning technique for the generation of patterned polymer coatings on ultrafiltration membranes. Polyethylene glycol, zwitterionic, or negatively charged hydrophilic polymer compositions in parallel- or perpendicular-striped patterns with respect to feed flow were evaluated using wastewater. Membrane fouling was dependent on the orientation and chemical composition of the coatings. Modifications reduced alpha diversity in the attached microbial community (Shannon indices decreased from 2.63 to 1.89) which nevertheless increased with filtration time. Sphingomonas species, which condition membrane surfaces and facilitate cellular adhesion, were depleted inmore » all modified membranes. Microbial community structure was significantly different between control, different patterns, and different chemistries. Lastly, this study broadens the tools for surface modification of membranes with polymer coatings and for understanding and optimization of antifouling surfaces.« less

Modeling the improvement of ultrafiltration membrane mass transfer when using biofiltration pretreatment in surface water applications.

PubMed

Netcher, Andrea C; Duranceau, Steven J

2016-03-01

In surface water treatment, ultrafiltration (UF) membranes are widely used because of their ability to supply safe drinking water. Although UF membranes produce high-quality water, their efficiency is limited by fouling. Improving UF filtrate productivity is economically desirable and has been attempted by incorporating sustainable biofiltration processes as pretreatment to UF with varying success. The availability of models that can be applied to describe the effectiveness of biofiltration on membrane mass transfer are lacking. In this work, UF water productivity was empirically modeled as a function of biofilter feed water quality using either a quadratic or Gaussian relationship. UF membrane mass transfer variability was found to be governed by the dimensionless mass ratio between the alkalinity (ALK) and dissolved organic carbon (DOC). UF membrane productivity was optimized when the biofilter feed water ALK to DOC ratio fell between 10 and 14. Copyright © 2015 Elsevier Ltd. All rights reserved.

Liquid Whey Protein Concentrates Produced by Ultrafiltration as Primary Raw Materials for Thermal
Dairy Gels

PubMed Central

2017-01-01

Summary The aim of this work is to study the gelation properties of liquid whey protein concentrates (LWPC) produced by ultrafiltration (UF) as raw material for thermally induced gels intended for food applications. LWPC thermal gelation was performed using different types of LWPC (non-
-defatted, defatted and diafiltered) of different protein mass fractions and pH. Most of the produced gels showed viscoelastic behaviour. Non-defatted LWPC gave stronger heat-induced gels with a more cohesive microstructure, a higher water holding capacity and also higher elastic modulus (G’) and viscous modulus (G’’). Gel properties were not improved in products with lower content of non-protein compounds. As expected, the increase in protein mass fraction positively influences protein interactions. However, the pH is responsible for the equilibrium between attraction and repulsion forces in the gel components that influence gel hardness and water holding capacity. PMID:29540980

Liquid Whey Protein Concentrates Produced by Ultrafiltration as Primary Raw Materials for Thermal
Dairy Gels.

PubMed

Henriques, Marta; Gomes, David; Pereira, Carlos

2017-12-01

The aim of this work is to study the gelation properties of liquid whey protein concentrates (LWPC) produced by ultrafiltration (UF) as raw material for thermally induced gels intended for food applications. LWPC thermal gelation was performed using different types of LWPC (non-
-defatted, defatted and diafiltered) of different protein mass fractions and pH. Most of the produced gels showed viscoelastic behaviour. Non-defatted LWPC gave stronger heat-induced gels with a more cohesive microstructure, a higher water holding capacity and also higher elastic modulus (G') and viscous modulus (G''). Gel properties were not improved in products with lower content of non-protein compounds. As expected, the increase in protein mass fraction positively influences protein interactions. However, the pH is responsible for the equilibrium between attraction and repulsion forces in the gel components that influence gel hardness and water holding capacity.

Modification of poly(vinylidene fluoride) ultrafiltration membranes with poly(vinyl alcohol) for fouling control in drinking water treatment.

PubMed

Du, Jennifer R; Peldszus, Sigrid; Huck, Peter M; Feng, Xianshe

2009-10-01

A commercial poly(vinylidene fluoride) flat sheet membrane was modified by surface coating with a dilute poly(vinyl alcohol) (PVA) aqueous solution followed by solid-vapor interfacial crosslinking. The resulting PVA layer increased membrane smoothness and hydrophilicity and resulted in comparable pure water permeation between the modified and unmodified membranes. Fouling tests using a 5 mg/L protein solution showed that a short period of coating and crosslinking improved the anti-fouling performance. After 18 h ultrafiltration of a surface water with a TOC of approximately 7 mg C/L, the flux of the modified membrane was twice as high as that of the unmodified membrane. The improved fouling resistance of the modified membrane was related to the membrane physiochemical properties, which were confirmed by pure water permeation, X-ray photoelectron spectroscopy, and contact angle, zeta potential and roughness measurements.

Production and recovery of monosaccharides from lignocellulose hot water extracts in a pulp mill biorefinery.

PubMed

Sainio, Tuomo; Kallioinen, Mari; Nakari, Olli; Mänttäri, Mika

2013-05-01

Processing of hemicelluloses obtained with pressurized hot water extraction (PHWE) from Scots pine to monosaccharides and other chemicals was investigated experimentally. A process scheme consisting of ultrafiltration, acid hydrolysis, and chromatographic separation was proposed and evaluated. A two-stage ultrafiltration was found necessary for efficient fractionation of the wood extract. It was shown that the monosaccharides can be released from a concentrated hemicellulose fraction with sulfuric acid hydrolysis without a significant loss of yield due to decomposition of monosaccharides. Acid hydrolysate was successfully fractionated with ion exchange chromatography and the hydrolysis acid was recovered for reuse. The product fractions obtained include polyphenols and high molar mass hemicelluloses (from UF stage 1), arabinose (from UF stage 2), as well as acetic acid and a mixture of monosaccharides (xylose, galactose, mannose, glucose) from chromatography. Copyright © 2012 Elsevier Ltd. All rights reserved.

From lab to full-scale ultrafiltration in microalgae harvesting

NASA Astrophysics Data System (ADS)

Wenten, I. G.; Steven, S.; Dwiputra, A.; Khoiruddin; Hakim, A. N.

2017-07-01

Ponding system is generally used for microalgae cultivation. However, selection of appropriate technology for the harvesting process is challenging due to the low cell density of cultivated microalgae from the ponding system and the large volume of water to be handled. One of the promising technologies for microalgae harvesting is ultrafiltration (UF). In this study, the performance of UF during harvesting of microalgae in a lab- and a full-scale test is investigated. The performances of both scales are compared and analyzed to provide an understanding of several aspects which affect the yield produced from lab and actual conditions. Furthermore, a unique self-standing non-modular UF is introduced in the full-scale test. The non-modular UF exhibits several advantages, such as simple piping and connection, single pump for filtration and backwashing, and smaller footprint. With those advantages, the non-modular UF could be a promising technology for microalgae harvesting in industrial-scale.

Bacterial challenge of NISSHO ultrafilter ETF 609: results of in vitro testing.

PubMed

Krautzig, S; Lonnemann, G; Shaldon, S; Koch, K M

1996-07-01

In hemodialysis, a certain degree of bacterial contamination on the dialysate side is a regular finding. Concern has been growing that this contamination may lead to a chronic inflammatory response in the patient. Ultrafiltration of dialysate can be used to reduce bacterial content and levels of cytokine-inducing substances upstream of the patient's dialyzer. The aim of this study was to test in vitro the rejection capacity of a polysulfone hollow-fiber ultrafilter (ETF 609, NISSHO Co., Osaka, Japan) challenged with bacterial filtrates derived from Pseudomonas aeruginosa PA103. Results showed a reduction of interleukin-1 beta-inducing activity (measured on peripheral blood mononuclear cells) from 5,035 +/- 394 pg/ml prefilter to nondetectable levels postfilter and endotoxin levels (limulus amebocyte lysate assay) of 4,167 +/- 1,079 versus 12 +/- 2 pg/ml, respectively. In conclusion, ultrafiltration of dialysate with the polysulfone ultrafilter ETF 609 leads to a potent reduction of cytokine-inducing activity.

A Review of Ultrafiltration and Forward Osmosis:application and modification

NASA Astrophysics Data System (ADS)

Chao, Gong; Shuili, Yu; Yufei, Shangguan; Zhengyang, Gu; Wangzhen, Yang; Liumo, Ren

2018-03-01

As a new treatment, membrane filtration is playing a more prominent role in treating many kinds of wastewater. Among all the membrane technologies, ultrafiltration(UF) and forward osmosis(FO) technology has been widely utilized and developed in oil field and refinery produced water. However, the reports about the differences between the two kinds of membrane technology used in oily wastewater are not yet available. In this review, at first we introduce the advantages, shortcomings and applications of UF and FO membranes. Among these, we mainly illustrate the membrane fouling, which now is a big problem because it increases costs and decreases membrane life to limit the industrialization of the membrane, and the different modification methods of membranes are discussed to figure out how these ways can ease the membrane fouling. Next we make a comparison of the two membranes. Finally we illustrate the future research topics.

Comparative analysis of methods for concentrating venom from jellyfish Rhopilema esculentum Kishinouye

NASA Astrophysics Data System (ADS)

Li, Cuiping; Yu, Huahua; Feng, Jinhua; Chen, Xiaolin; Li, Pengcheng

2009-02-01

In this study, several methods were compared for the efficiency to concentrate venom from the tentacles of jellyfish Rhopilema esculentum Kishinouye. The results show that the methods using either freezing-dry or gel absorption to remove water to concentrate venom are not applicable due to the low concentration of the compounds dissolved. Although the recovery efficiency and the total venom obtained using the dialysis dehydration method are high, some proteins can be lost during the concentrating process. Comparing to the lyophilization method, ultrafiltration is a simple way to concentrate the compounds at high percentage but the hemolytic activities of the proteins obtained by ultrafiltration appear to be lower. Our results suggest that overall lyophilization is the best and recommended method to concentrate venom from the tentacles of jellyfish. It shows not only the high recovery efficiency for the venoms but high hemolytic activities as well.

A two-stage ultrafiltration and nanofiltration process for recycling dairy wastewater.

PubMed

Luo, Jianquan; Ding, Luhui; Qi, Benkun; Jaffrin, Michel Y; Wan, Yinhua

2011-08-01

A two-stage ultrafiltration and nanofiltration (UF/NF) process for the treatment of model dairy wastewater was investigated to recycle nutrients and water from the wastewater. Ultracel PLGC and NF270 membranes were found to be the most suitable for this purpose. In the first stage, protein and lipid were concentrated by the Ultracel PLGC UF membrane and could be used for algae cultivation to produce biodiesel and biofuel, and the permeate from UF was concentrated by the NF270 membrane in the second stage to obtain lactose in retentate and reusable water in permeate, while the NF retentate could be recycled for anaerobic digestion to produce biogas. With this approach, most of dairy wastewater could be recycled to produce reusable water and substrates for bioenergy production. Compared with the single NF process, this two-stage UF/NF process had a higher efficiency and less membrane fouling. Copyright © 2011 Elsevier Ltd. All rights reserved.

Experiments on the heat-induced salt balance changes in cow's milk.

PubMed

Pouliot, Y; Boulet, M; Paquin, P

1989-01-01

The heat-induced changes in salt balance between the colloidal phase of milk and its serum were studied using an ultrafiltration technique. Milk permeate was isolated at the heating temperature by means of a hollow fibre ultrafiltration cartridge coupled with a stainless steel heat exchanger unit. The milk samples initially at 4 degrees C were heated to 20, 40, 60, 80 or 90 degrees C. Ca, P, Mg and citrate contents of the permeates were determined. The decreases in Ca and P were proportional to the increase in temperature. Smaller losses in Mg and citrate were observed. An initial sharp decrease in concentration occurred within the first seconds of holding time and was followed by a slower and smaller decrease. The possible occurrence of a two-stage mechanism for the heat-induced salt precipitation is discussed. The precipitation of dicalcium phosphate is believed to occur together with some tricalcium citrate precipitation.

Integrated process for the removal of emulsified oils from effluents in the steel industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benito, J.M.; Rios, G.; Gutierrez, B.

1999-11-01

Emulsified oils contained in aqueous effluents from cold-rolling mills of the steel industry can be effectively removed via an integrated process consisting of a coagulation/flocculation stage followed by ultrafiltration of the resulting aqueous phase. The effects of CaCl{sub 2}, NaOH, and lime on the stability of different industrial effluents were studied in the coagulation experiments. The flocculants tested were inorganic prehydrolyzed aluminum salts and quaternary polyamines. Ultrafiltration of the aqueous phase from the coagulation/flocculation stage was carried out in a stirred cell using Amicon PM30 and XM300 organic membranes. Permeate fluxes were measured for industrial effluents to which the indicatedmore » coagulants and flocculants had been added. Oil concentrations in the permeate were 75% lower than the limits established by all European Union countries. Complete regeneration of the membrane was accomplished with an aqueous solution of a commercial detergent.« less

Stall in Women's Real Wage Growth Slows Progress in Closing the Wage Gap. Briefing Paper.

ERIC Educational Resources Information Center

Hartmann, Heidi; Whittaker, Julie

Since 1979, the wage gap between women and men has narrowed significantly, falling by more than 10 percent overall. The closing of the wage gap has slowed considerably in the 1990's, however, with women's real wages (adjusted for inflation) stagnating in recent year and men's wages continuing to decline. The lack of growth in both women's and…

Wall street comes to Washington.

PubMed

2004-08-01

While health care cost trends likely will continue slowing through the end of 2004, the longer-term outlook for a sustained slowdown in underlying costs and private health insurance premiums largely depends on the strength of the economy, according to market and health policy experts at the Center for Studying Health System Change's (HSC) ninth annual Wall Street roundtable. Even as cost growth slows, insurers are practicing pricing discipline to keep premium trends ahead of cost trends to maintain profitability. Employers will continue to shift costs to workers through higher deductibles, copayments and coinsurance, but an improving economy could temper this trend as labor markets tighten. Employers remain skeptical of new health insurance products, including tiered-provider networks and consumer-driven health plans. Although growth in hospital use has slowed, the industry remains in the throes of a building boom. Increased payments to managed care plans could reinvigorate private plan participation in Medicare, but concerns about the federal budget deficit could prompt Congress to roll back rate increases.

Screening for Natural Inhibitors of Topoisomerases I from Rhamnus davurica by Affinity Ultrafiltration and High-Performance Liquid Chromatography–Mass Spectrometry

PubMed Central

Chen, Guilin; Guo, Mingquan

2017-01-01

Topoisomerase I (Topo I) catalyzes topological interconversion of duplex DNA during DNA replication and transcription, and has been deemed as important antineoplastic targets. In this study, the fraction R.d-60 from ethyl acetate extracts of Rhamnus davurica showed higher inhibitory rates against SGC-7901 and HT-29 compared with the R.d-30 fraction in vitro. However, the specific active components of R.d-60 fraction remain elusive. To this end, a method based on bio-affinity ultrafiltration and high performance liquid chromatography/electrospray mass spectrometry (HPLC- ESI-MS/MS) was developed to rapidly screen and identify the Topo I inhibitors in this fraction. The enrichment factors (EFs) were calculated to evaluate the binding affinities between the bioactive constituents and Topo I. As a result, eight ligands were identified and six of which with higher EFs showed more potential antitumor activity. Furthermore, antiproliferative assays in vitro (IC50 values) with two representative candidates (apigenin, quercetin) against SGC-7901, HT-29 and Hep G2 cells were conducted and further validated. Finally, the structure-activity relationships revealed that flavones contain a C2-C3 double bond of C ring exhibited higher bio-affinities to Topo I than those without it. This integrated method combining Topo I ultrafiltration with HPLC-MS/MS proved to be very efficient in rapid screening and identification of potential Topo I inhibitors from the complex extracts of medicinal plants, and could be further explored as a valuable high-throughput screening platform in the early drug discovery stage. PMID:28919906

Characterization of the Low-Molecular-Weight Human Plasma Peptidome.

PubMed

Greening, David W; Simpson, Richard J

2017-01-01

The human plasma proteome represents an important secreted sub-proteome. Proteomic analysis of blood plasma with mass spectrometry is a challenging task. The high complexity and wide dynamic range of proteins as well as the presence of several proteins at very high concentrations complicate the profiling of the human plasma proteome. The peptidome (or low-molecular-weight fraction, LMF) of the human plasma proteome is an invaluable source of biological information, especially in the context of identifying plasma-based markers of disease. Peptides are generated by active synthesis and proteolytic processing, often yielding proteolytic fragments that mediate a variety of physiological and pathological functions. As such, degradomic studies, investigating cleavage products via peptidomics and top-down proteomics in particular, have warranted significant research interest. However, due to their molecular weight, abundance, and solubility, issues with identifying specific cleavage sites and coverage of peptide fragments remain challenging. Peptidomics is currently focused toward comprehensively studying peptides cleaved from precursor proteins by endogenous proteases. This protocol outlines a standardized rapid and reproducible procedure for peptidomic profiling of human plasma using centrifugal ultrafiltration and mass spectrometry. Ultrafiltration is a convective process that uses anisotropic semipermeable membranes to separate macromolecular species on the basis of size. We have optimized centrifugal ultrafiltration (cellulose triacetate membrane) for plasma fractionation with respect to buffer and solvent composition, centrifugal force, duration, and temperature to facilitate recovery >95% and enrichment of the human plasma peptidome. This method serves as a comprehensive and facile process to enrich and identify a key, underrepresented sub-proteome of human blood plasma.

Towards sustainable membrane filtration of palm oil mill effluent: analysis of fouling phenomena from a hybrid PAC-UF process

NASA Astrophysics Data System (ADS)

Amosa, Mutiu Kolade

2017-10-01

Sustainability of a membrane process depends on many factors of which fouling mitigation is the most central. Because membrane fouling phenomenon is very complex, extent of fouling potential of a feedwater with respect to a membrane has to be identified right from the design stage. This will acquaint engineers with the proper fouling mitigation measures during operation. This study presents a preliminary fouling data from the ultrafiltration of biotreated palm oil mill effluent (POME) after an upstream adsorption process. The flux decline is studied in a typical constant-pressure experiments with a cross-flow ultrafiltration of biotreated POME through Sartocon® polyethersulfone membranes (MWCOs 1, 5 and 10 kDa) at applied pressures of 40, 80 and 120 kPa. Results are examined, within the frame of the common blocking mechanisms and it was found that the blocking index η decreased from 2 to 0. Pore blocking phenomenon was successively observed from complete blocking ( η = 2) down to cake filtration ( η = 0), and the early blockage of the pores and a formation of a cake resulted in a limiting cake height. Thus, cake filtration could be best used to explain the fouling mechanisms of biotreated POME on the ultrafiltration membranes based on the R 2 values at all applied pressures. This demonstrates that the fouling was as a result of gradual reversible cake deposition which could easily be removed by less onerous cleaning methods. In addition, it could be concluded that the upstream adsorption reduced the particulate deposition on the membrane surface.

Interplay of different NOM fouling mechanisms during ultrafiltration for drinking water production.

PubMed

Jermann, D; Pronk, W; Meylan, S; Boller, M

2007-04-01

Ultrafiltration is an emerging technology for drinking water production, but a main challenge remains the lack of understanding about fouling. This paper investigates the impact of molecular interactions between different natural organic matter (NOM) compounds on ultrafiltration fouling mechanisms. We performed dead-end filtration experiments with individual and mixed humic acid and alginate (polysaccharide). Alginate showed detrimental, but mostly reversible, flux decline and high solute retention. Our results indicate that this was caused by pore blocking transformed into cake building and weak molecular foulant-membrane and foulant-foulant interactions. In the presence of calcium, aggravated fouling was observed, related to complexation of alginate and its subsequently induced gel formation. With humic acid, more severe irreversible fouling occurred due to humic acid adsorption. Minor adsorption of alginate onto the membrane was also observed, which probably caused the substantial irreversible flux decline. The fouling characteristics in the mixtures reflected a combination of the individual humic acid and alginate experiments and we conclude, that the individual fouling mechanisms mutually influence each other. A model elucidates this interplay of the individual fouling mechanisms via hydrophobic and electrostatic interactions. In our study such an interplay resulted in an alginate cake, or gel in the presence of calcium, which is relatively irreversibly adsorbed onto the membrane by humic acid associations. This study shows the importance of mutual influences between various foulants for improved understanding of fouling phenomena. Furthermore it shows that substances with a minor individual influence might have a large impact in mixed systems such as natural water.

Production and characterisation of whey protein hydrolysate having antioxidant activity from cheese whey.

PubMed

Athira, Syamala; Mann, Bimlesh; Saini, Prerna; Sharma, Rajan; Kumar, Rajesh; Singh, Ashish Kumar

2015-11-01

Cheese whey is a rich by-product in nutritional terms, possessing components with high biological value, excellent functional properties, and an inert flavour profile. In the present study, mozzarella cheese whey was ultra-filtrated to remove lactose and mineral. The retentate was hydrolysed with food-grade enzyme alcalase and the hydrolysis conditions (pH, temperature and time) were optimised for maximum antioxidant activity using response surface methodology. Whey protein hydrolysed for 8 h at pH 9 and 55 °C showed a maximum antioxidant activity of 1.18 ± 0.015 µmol Trolox mg(-1) protein. The antioxidant peptides were further enriched by ultra-filtration through a 3 kDa membrane. Seven peptides - β-Lg f(123-131), β-Lg f(122-131), β-Lg f(124-131), β-Lg f(123-134), β-Lg f(122-131), β-Lg f(96-100) and β-Lg f(94-100) - were identified by LC-MS/MS in the 3 kDa permeate of the hydrolysate. The incorporation of whey protein hydrolysate (WPH) in lemon whey drink (5-10 g L(-1)) increased the antioxidant activity from 76% to 90% as compared to control. Hydrolysis of ultra-filtrated retentate of whey can be an energy- and cost-effective method for the direct production of WPH from whey compared to the industrial production of WPH from whey protein concentrate. This study suggests that WPH with good nutritional and biological properties can be effectively used in health-promoting foods as a biofunctional ingredient. © 2014 Society of Chemical Industry.

Ionic-liquid-based ultrasound-assisted extraction of isoflavones from Belamcanda chinensis and subsequent screening and isolation of potential α-glucosidase inhibitors by ultrafiltration and semipreparative high-performance liquid chromatography.

PubMed

Li, Senlin; Li, Sainan; Huang, Yu; Liu, Chunming; Chen, Lina; Zhang, Yuchi

2017-06-01

The separation of a compound of interest from its structurally similar homologues to produce high-purity natural products is a challenging problem. This work proposes a novel method for the separation of iristectorigenin A from its structurally similar homologues by ionic-liquid-based ultrasound-assisted extraction and the subsequent screening and isolation of potential α-glucosidase inhibitors via ultrafiltration and semipreparative high-performance liquid chromatography. Ionic-liquid-based ultrasound-assisted extraction was successfully applied to the extraction of tectorigenin, iristectorigenin A, irigenin, and irisflorentin from Belamcanda chinensis. The optimum conditions for the efficient extraction of isoflavones were determined as 1.0 M 1-ethyl-3-methylimidazolium tetrafluoroborate with extraction time of 30 min and a solvent to solid ratio of 30 mL/g. Ultrafiltration with liquid chromatography and mass spectrometry was applied to screen and identify α-glucosidase inhibitors from B. chinensis, followed by the application of semipreparative high-performance liquid chromatography to separate and isolate the active constituents. Four major compounds including tectorigenin, iristectorigenin A, irigenin, and irisflorentin were screened and identified as α-glucosidase inhibitors, and then the four active compounds abovementioned were subsequently isolated by semipreparative high-performance liquid chromatography (99.89, 88.97, 99.79, and 99.97% purity, respectively). The results demonstrate that ionic liquid extraction can be successfully applied to the extraction of isoflavones from B. chinensis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultrafiltration and Microarray for Detection of Microbial Source Tracking Marker and Pathogen Genes in Riverine and Marine Systems

PubMed Central

Li, Xiang; Harwood, Valerie J.; Nayak, Bina

2016-01-01

Pathogen identification and microbial source tracking (MST) to identify sources of fecal pollution improve evaluation of water quality. They contribute to improved assessment of human health risks and remediation of pollution sources. An MST microarray was used to simultaneously detect genes for multiple pathogens and indicators of fecal pollution in freshwater, marine water, sewage-contaminated freshwater and marine water, and treated wastewater. Dead-end ultrafiltration (DEUF) was used to concentrate organisms from water samples, yielding a recovery efficiency of >95% for Escherichia coli and human polyomavirus. Whole-genome amplification (WGA) increased gene copies from ultrafiltered samples and increased the sensitivity of the microarray. Viruses (adenovirus, bocavirus, hepatitis A virus, and human polyomaviruses) were detected in sewage-contaminated samples. Pathogens such as Legionella pneumophila, Shigella flexneri, and Campylobacter fetus were detected along with genes conferring resistance to aminoglycosides, beta-lactams, and tetracycline. Nonmetric dimensional analysis of MST marker genes grouped sewage-spiked freshwater and marine samples with sewage and apart from other fecal sources. The sensitivity (percent true positives) of the microarray probes for gene targets anticipated in sewage was 51 to 57% and was lower than the specificity (percent true negatives; 79 to 81%). A linear relationship between gene copies determined by quantitative PCR and microarray fluorescence was found, indicating the semiquantitative nature of the MST microarray. These results indicate that ultrafiltration coupled with WGA provides sufficient nucleic acids for detection of viruses, bacteria, protozoa, and antibiotic resistance genes by the microarray in applications ranging from beach monitoring to risk assessment. PMID:26729716

Structure and chemical composition of layers adsorbed at interfaces with champagne.

PubMed

Aguié-Béghin, V; Adriaensen, Y; Péron, N; Valade, M; Rouxhet, P; Douillard, R

2009-11-11

The structure and the chemical composition of the layer adsorbed at interfaces involving champagne have been investigated using native champagne, as well as ultrafiltrate (UFch) and ultraconcentrate (UCch) obtained by ultrafiltration with a 10(4) nominal molar mass cutoff. The layer adsorbed at the air/liquid interface was examined by surface tension and ellipsometry kinetic measurements. Brewster angle microscopy demonstrated that the layer formed on polystyrene by adsorption or drop evaporation was heterogeneous, with a domain structure presenting similarities with the layer adsorbed at the air/liquid interface. The surface chemical composition of polystyrene with the adlayer was determined by X-ray photoelectron spectroscopy (XPS). The contribution of champagne constituents varied according to the liquid (native, UFch, and UCch) and to the procedure of adlayer formation (evaporation, adsorption, and adsorption + rinsing). However, their chemical composition was not significantly influenced either by ultrafiltration or by the procedure of deposition on polystyrene. Modeling this composition in terms of classes of model compounds gave approximately 35% (w/w) of proteins and 65% (w/w) of polysaccharides. In the adlayer, the carboxyl groups or esters represent about 18% of carbon due to nonpolypeptidic compounds, indicating the presence of either uronic acids in the complex structure of pectic polysaccharides or of polyphenolic esters. This structural and chemical information and its relationship with the experimental procedures indicate that proteins alone cannot be used as a realistic model for the macromolecules forming the adsorption layer of champagne. Polysaccharides, the other major macromolecular components of champagne wine, are assembled with proteins at the interfaces, in agreement with the heterogeneous character of the adsorbed layer at interfaces.

Immunological Relationship of Different Preparations of Coliform Enterotoxins

PubMed Central

Klipstein, Frederick A.; Engert, Richard F.

1978-01-01

Antisera raised in rabbits to ultrafiltrate toxin preparations containing either the heat-labile (LT) toxin form obtained from whole cell lysates or broth filtrates or the heat-stable (ST) toxin form prepared from broth filtrates from nontoxigenic and toxigenic strains of Escherichia coli and Klebsiella were examined for their ability to neutralize the secretory effect on water transport of these toxins in the rat jejunum as determined by the in vivo marker perfusion technique. Antisera to the heat-labile toxin derived from whole cell lysate preparations from nontoxigenic strains had no neutralizing effect. Antisera to both types of LT preparation from both toxigenic strains neutralized, with several exceptions, all of the homologous and heterologous LT toxins as well as a heat-labile toxin preparation derived from sequential ultrafiltration of cell-free whole cell lysates which had a defined molecular weight of between 30,000 and 100,000. These antisera also neutralized homologous and heterologous ST preparations obtained from broth filtrates, but they had no neutraliziṅg effect on low-molecular-weight, ST toxin material obtained during the sequential ultrafiltration of cell lysates. Antisera to ST prepared from broth filtrates had no neutralizing capacity against either LT or ST toxin preparations. These observations (i) indicate that the immunological relationship of E. coli and Klebsiella LT and ST toxins extends to antisera raised against LT prepared by several different methods, (ii) raise the possibility that, based on the response to antisera to LT, there may be several immunologically heterogeneous forms of low-molecular-weight ST toxin, and (c) confirm the lack of immunogenicity of ST. PMID:361578

The Potential Source of B. licheniformis Contamination During Whey Protein Concentrate 80 Manufacture.

PubMed

Md Zain, Siti Norbaizura; Bennett, Rod; Flint, Steve

2017-03-01

The objective of this study was to determine the possible source of predominant Bacillus licheniformis contamination in a whey protein concentrate (WPC) 80 manufacturing plant. Traditionally, microbial contaminants of WPC were believed to grow on the membrane surfaces of the ultrafiltration plant as this represents the largest surface area in the plant. Changes from hot to cold ultrafiltration have reduced the growth potential for bacteria on the membrane surfaces. Our recent studies of WPCs have shown the predominant microflora B. licheniformis would not grow in the membrane plant because of the low temperature (10 °C) and must be growing elsewhere. Contamination of dairy products is mostly due to bacteria being released from biofilm in the processing plant rather from the farm itself. Three different reconstituted WPC media at 1%, 5%, and 20% were used for biofilm growth and our results showed that B. licheniformis formed the best biofilm at 1% (low solids). Further investigations were done using 3 different media; tryptic soy broth, 1% reconstituted WPC80, and 1% reconstituted WPC80 enriched with lactose and minerals to examine biofilm growth of B. licheniformis on stainless steel. Thirty-three B. licheniformis isolates varied in their ability to form biofilm on stainless steel with stronger biofilm in the presence of minerals. The source of biofilms of thermo-resistant bacteria such as B. licheniformis is believed to be before the ultrafiltration zone represented by the 1% WPC with lactose and minerals where the whey protein concentration is about 0.6%. © 2017 Institute of Food Technologists®.

Removal of toxic metals during biological treatment of landfill leachates.

PubMed

Robinson, T

2017-05-01

Progressive implementation of the European Water Framework Directive has resulted in substantial changes in limits for discharges of heavy metals both to watercourses, and to sewer. The objective of this paper is to provide original, real, full-scale data obtained for removal of metals during aerobic biological leachate treatment, and also to report on studies carried out to look at further trace metal removal. Polishing technologies examined and investigated include; the incorporation of ultrafiltration (UF) membranes into biological treatment systems, the use of ion exchange, and of activated carbon polishing processes. Ultrafiltration was able to provide a 60 percent reduction in COD values in treated leachates, compared with COD values found in settled/clarified effluents. Removal rates for COD varied from 30.5 to 79.8 percent. Additionally, ultrafiltration of treated leachates significantly reduced both chromium and nickel concentrations of effluents by 61.6% and 34.3% respectively (median values). Despite mean reductions of chromium (9.7%) and nickel (13.7%) noted during the ion exchange trials, these results would not justify use of this technology for metals removal at full-scale. Further preliminary studies used pulverized activated carbon (PAC) polishing of UF effluents to demonstrate that significant (up to 80 per cent) removal of COD, TOC and heavy metals could readily be achieved by doses of up to 10g/l of suitable activated carbons. Additional evidence is provided that many trace metals are present not in ionic form, but as organic complexes; this is likely to make their removal to low levels more difficult and expensive. Copyright © 2016 Elsevier Ltd. All rights reserved.

UF/RO applications at the Browns Ferry Nuclear Power Station

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palino, G.F.; Sailor, W.C.; Sawochka, S.G.

1981-04-01

In June 1979, NWT was contracted by TVA to review the applicability of reverse osmosis (RO) and ultrafiltration (UF) membrane treatment technology at the Browns Ferry Nuclear Power Station. Specific program tasks are described and results presented.

Simplified process for preparation of schizophyllan solutions for biomaterial applications

USDA-ARS?s Scientific Manuscript database

Schizophyllan is a biopolymer commercially produced for pharmaceutical and cosmetics uses. However, schizophyllan also has potential biomaterial applications. Schizophyllan is conventionally produced from glucose and recovered by diafiltration and ultrafiltration to produce a highly purified product...

Design of a Nutrient Reclamation System for the Cultivation of Microalgae for Biofuel Production and Other Industrial Applications

NASA Astrophysics Data System (ADS)

Sandefur, Heather Nicole

Microalgal biomass has been identified as a promising feedstock for a number of industrial applications, including the synthesis of new pharmaceutical and biofuel products. However, there are several economic limitations associated with the scale up of existing algal production processes. Critical economic studies of algae-based industrial processes highlight the high cost of supplying essential nutrients to microalgae cultures. With microalgae cells having relatively high nitrogen contents (4 to 8%), the N fertilizer cost in industrial-scale production is significant. In addition, the disposal of the large volumes of cell residuals that are generated during product extraction stages can pose other economic challenges. While waste streams can provide a concentrated source of nutrients, concerns about the presence of biological contaminants and the expense of heat treatment pose challenges to processes that use wastewater as a nutrient source in microalgae cultures. The goal of this study was to evaluate the potential application of ultrafiltration technology to aid in the utilization of agricultural wastewater in the cultivation of a high-value microalgae strain. An ultrafiltration system was used to remove inorganic solids and biological contaminants from wastewater taken from a swine farm in Savoy, Arkansas. The permeate from the system was then used as the nutrient source for the cultivation of the marine microalgae Porphyridium cruentum. During the ultrafiltration system operation, little membrane fouling was observed, and permeate fluxes remained relatively constant during both short-term and long-term tests. The complete rejection of E. coli and coliforms from the wastewater was also observed, in addition to a 75% reduction in total solids, including inorganic materials. The processed permeate was shown to have very high concentrations of total nitrogen (695.6 mg L-1) and total phosphorus (69.1 mg L-1 ). In addition, the growth of P. cruentum was analyzed in a medium containing swine waste permeate, and was compared to P. cruentum growth in a control medium. A higher biomass productivity, lipid productivity, and lipid content were observed in the microalgae cultivated in the swine waste medium compared to that of the control medium. These results suggest that, through the use of ultrafiltration technology as an alternative to traditional heat treatment, agricultural wastewaters could be effectively utilized as a nutrient source for microalgae cultivation.

Blood volume-monitored regulation of ultrafiltration in fluid-overloaded hemodialysis patients: study protocol for a randomized controlled trial.

PubMed

Hecking, Manfred; Antlanger, Marlies; Winnicki, Wolfgang; Reiter, Thomas; Werzowa, Johannes; Haidinger, Michael; Weichhart, Thomas; Polaschegg, Hans-Dietrich; Josten, Peter; Exner, Isabella; Lorenz-Turnheim, Katharina; Eigner, Manfred; Paul, Gernot; Klauser-Braun, Renate; Hörl, Walter H; Sunder-Plassmann, Gere; Säemann, Marcus D

2012-06-08

Data generated with the body composition monitor (BCM, Fresenius) show, based on bioimpedance technology, that chronic fluid overload in hemodialysis patients is associated with poor survival. However, removing excess fluid by lowering dry weight can be accompanied by intradialytic and postdialytic complications. Here, we aim at testing the hypothesis that, in comparison to conventional hemodialysis, blood volume-monitored regulation of ultrafiltration and dialysate conductivity (UCR) and/or regulation of ultrafiltration and temperature (UTR) will decrease complications when ultrafiltration volumes are systematically increased in fluid-overloaded hemodialysis patients. BCM measurements yield results on fluid overload (in liters), relative to extracellular water (ECW). In this prospective, multicenter, triple-arm, parallel-group, crossover, randomized, controlled clinical trial, we use BCM measurements, routinely introduced in our three maintenance hemodialysis centers shortly prior to the start of the study, to recruit sixty hemodialysis patients with fluid overload (defined as ≥15% ECW). Patients are randomized 1:1:1 into UCR, UTR and conventional hemodialysis groups. BCM-determined, 'final' dry weight is set to normohydration weight -7% of ECW postdialysis, and reached by reducing the previous dry weight, in steps of 0.1 kg per 10 kg body weight, during 12 hemodialysis sessions (one study phase). In case of intradialytic complications, dry weight reduction is decreased, according to a prespecified algorithm. A comparison of intra- and post-dialytic complications among study groups constitutes the primary endpoint. In addition, we will assess relative weight reduction, changes in residual renal function, quality of life measures, and predialysis levels of various laboratory parameters including C-reactive protein, troponin T, and N-terminal pro-B-type natriuretic peptide, before and after the first study phase (secondary outcome parameters). Patients are not requested to revert to their initial degree of fluid overload after each study phase. Therefore, the crossover design of the present study merely serves the purpose of secondary endpoint evaluation, for example to determine patient choice of treatment modality. Previous studies on blood volume monitoring have yielded inconsistent results. Since we include only patients with BCM-determined fluid overload, we expect a benefit for all study participants, due to strict fluid management, which decreases the mortality risk of hemodialysis patients. ClinicalTrials.gov, NCT01416753.

Blood volume-monitored regulation of ultrafiltration in fluid-overloaded hemodialysis patients: study protocol for a randomized controlled trial

PubMed Central

2012-01-01

Background Data generated with the body composition monitor (BCM, Fresenius) show, based on bioimpedance technology, that chronic fluid overload in hemodialysis patients is associated with poor survival. However, removing excess fluid by lowering dry weight can be accompanied by intradialytic and postdialytic complications. Here, we aim at testing the hypothesis that, in comparison to conventional hemodialysis, blood volume-monitored regulation of ultrafiltration and dialysate conductivity (UCR) and/or regulation of ultrafiltration and temperature (UTR) will decrease complications when ultrafiltration volumes are systematically increased in fluid-overloaded hemodialysis patients. Methods/design BCM measurements yield results on fluid overload (in liters), relative to extracellular water (ECW). In this prospective, multicenter, triple-arm, parallel-group, crossover, randomized, controlled clinical trial, we use BCM measurements, routinely introduced in our three maintenance hemodialysis centers shortly prior to the start of the study, to recruit sixty hemodialysis patients with fluid overload (defined as ≥15% ECW). Patients are randomized 1:1:1 into UCR, UTR and conventional hemodialysis groups. BCM-determined, ‘final’ dry weight is set to normohydration weight −7% of ECW postdialysis, and reached by reducing the previous dry weight, in steps of 0.1 kg per 10 kg body weight, during 12 hemodialysis sessions (one study phase). In case of intradialytic complications, dry weight reduction is decreased, according to a prespecified algorithm. A comparison of intra- and post-dialytic complications among study groups constitutes the primary endpoint. In addition, we will assess relative weight reduction, changes in residual renal function, quality of life measures, and predialysis levels of various laboratory parameters including C-reactive protein, troponin T, and N-terminal pro-B-type natriuretic peptide, before and after the first study phase (secondary outcome parameters). Discussion Patients are not requested to revert to their initial degree of fluid overload after each study phase. Therefore, the crossover design of the present study merely serves the purpose of secondary endpoint evaluation, for example to determine patient choice of treatment modality. Previous studies on blood volume monitoring have yielded inconsistent results. Since we include only patients with BCM-determined fluid overload, we expect a benefit for all study participants, due to strict fluid management, which decreases the mortality risk of hemodialysis patients. Trial registration ClinicalTrials.gov, NCT01416753 PMID:22682149

Comparison of ultrafiltration and solid phase extraction for the separation of free and protein-bound serum copper for the Wilson's disease diagnosis.

PubMed

Bohrer, Denise; Do Nascimento, Paulo Cícero; Ramirez, Adrian G; Mendonça, Jean Karlo A; De Carvalho, Leandro M; Pomblum, Solange Cristina G

2004-07-01

The determination of the ratio free/protein-bound serum copper along with urinary copper can be used as a preliminary test for the Wilson's Disease diagnosis. In this work, the determination of these copper fractions in serum samples was carried out in two different ways; after separation of the copper bound to proteins from the free fraction by a column for protein adsorption and by ultrafiltration. As proteins can be adsorbed onto plastic polymeric surfaces, polyethylene (PE) with different molecular weights in powder form was investigated for protein adsorption. A small column was adapted in a flow system to carry out a solid-phase extraction (SPE) on-line. Preliminary experiments defined conditions for protein retention and elution and column saturation. Good performance was achieved using Mg(NO3)2 solution as carrier and methanol as eluent. The presence of proteins in both fraction (column effluent and eluate) was checked by the Coomassie Brilliant Blue test. Copper was measured by graphite furnace atomic absorption spectrometry. The measurement in the column effluent furnished the free-fraction of copper while the copper measured in the eluate the bound-fraction. The method was compared with ultrafiltration (20 kDa), measuring the free-copper in the ultrafiltrate. For the determination of protein-bound copper, the copper found in the ultrafitrate was discounted from the total copper measured in the sample. Serum samples of 10 individuals were analyzed by both methods with good agreement of the results. The regression plots, obtained by analysing the samples by both methods, presented r2 and slope of 0.97 and 0.96 for free copper and 1.00 and 1.00 for bound copper, respectively. Protein-bound copper (PB) concentrations ranged from 74 to 2074 microg/l and free-copper (F) from 22 to 54 microg/l. The ratio F/PB, calculated from SPE data, was 29.7% for one individual, with Wilson Disease well-characterized, and ranged from 1.2% to 5.2% for the others. The SPE method performed well in terms of accuracy and precision, and showed good agreement with the UF. Advantages of SPE are small sample volume (50 microl), separation carried out in 10 min, and the use of the same column for several analyses. Copyright 2004 Elsevier B.V.

Areas prone to slow slip events impede earthquake rupture propagation and promote afterslip.

PubMed

Rolandone, Frederique; Nocquet, Jean-Mathieu; Mothes, Patricia A; Jarrin, Paul; Vallée, Martin; Cubas, Nadaya; Hernandez, Stephen; Plain, Morgan; Vaca, Sandro; Font, Yvonne

2018-01-01

At subduction zones, transient aseismic slip occurs either as afterslip following a large earthquake or as episodic slow slip events during the interseismic period. Afterslip and slow slip events are usually considered as distinct processes occurring on separate fault areas governed by different frictional properties. Continuous GPS (Global Positioning System) measurements following the 2016 M w (moment magnitude) 7.8 Ecuador earthquake reveal that large and rapid afterslip developed at discrete areas of the megathrust that had previously hosted slow slip events. Regardless of whether they were locked or not before the earthquake, these areas appear to persistently release stress by aseismic slip throughout the earthquake cycle and outline the seismic rupture, an observation potentially leading to a better anticipation of future large earthquakes.

Areas prone to slow slip events impede earthquake rupture propagation and promote afterslip

PubMed Central

Rolandone, Frederique; Nocquet, Jean-Mathieu; Mothes, Patricia A.; Jarrin, Paul; Vallée, Martin; Cubas, Nadaya; Hernandez, Stephen; Plain, Morgan; Vaca, Sandro; Font, Yvonne

2018-01-01

At subduction zones, transient aseismic slip occurs either as afterslip following a large earthquake or as episodic slow slip events during the interseismic period. Afterslip and slow slip events are usually considered as distinct processes occurring on separate fault areas governed by different frictional properties. Continuous GPS (Global Positioning System) measurements following the 2016 Mw (moment magnitude) 7.8 Ecuador earthquake reveal that large and rapid afterslip developed at discrete areas of the megathrust that had previously hosted slow slip events. Regardless of whether they were locked or not before the earthquake, these areas appear to persistently release stress by aseismic slip throughout the earthquake cycle and outline the seismic rupture, an observation potentially leading to a better anticipation of future large earthquakes. PMID:29404404

On-line confidence monitoring during decision making.

PubMed

Dotan, Dror; Meyniel, Florent; Dehaene, Stanislas

2018-02-01

Humans can readily assess their degree of confidence in their decisions. Two models of confidence computation have been proposed: post hoc computation using post-decision variables and heuristics, versus online computation using continuous assessment of evidence throughout the decision-making process. Here, we arbitrate between these theories by continuously monitoring finger movements during a manual sequential decision-making task. Analysis of finger kinematics indicated that subjects kept separate online records of evidence and confidence: finger deviation continuously reflected the ongoing accumulation of evidence, whereas finger speed continuously reflected the momentary degree of confidence. Furthermore, end-of-trial finger speed predicted the post-decisional subjective confidence rating. These data indicate that confidence is computed on-line, throughout the decision process. Speed-confidence correlations were previously interpreted as a post-decision heuristics, whereby slow decisions decrease subjective confidence, but our results suggest an adaptive mechanism that involves the opposite causality: by slowing down when unconfident, participants gain time to improve their decisions. Copyright © 2017 Elsevier B.V. All rights reserved.

Ultrafiltration and nanofiltration membrane fouling by natural organic matter: Mechanisms and mitigation by pre-ozonation and pH.

PubMed

Yu, Wenzheng; Liu, Teng; Crawshaw, John; Liu, Ting; Graham, Nigel

2018-08-01

The fouling of ultrafiltration (UF) and nanofiltration (NF) membranes during the treatment of surface waters continues to be of concern and the particular role of natural organic matter (NOM) requires further investigation. In this study the effect of pH and surface charge on membrane fouling during the treatment of samples of a representative surface water (Hyde Park recreational lake) were evaluated, together with the impact of pre-ozonation. While biopolymers in the surface water could be removed by the UF membrane, smaller molecular weight (MW) fractions of NOM were poorly removed, confirming the importance of membrane pore size. For NF membranes the removal of smaller MW fractions (800 Da-10 kDa) was less than expected from their pore size; however, nearly all of the hydrophobic, humic-type substances could be removed by the hydrophilic NF membranes for all MW distributions (greater than 90%). The results indicated the importance of the charge and hydrophilic nature of the NOM. Thus, the hydrophilic NF membrane could remove the hydrophobic organic matter, but not the hydrophilic substances. Increasing charge effects (more negative zeta potentials) with increasing solution pH were found to enhance organics removal and reduce fouling (flux decline), most likely through greater membrane surface repulsion. Pre-ozonation of the surface water increased the hydrophilic fraction and anionic charge of NOM and altered their size distributions. This resulted in a decreased fouling (less flux decline) for the UF and smaller pore NF, but a slight increase in fouling for the larger pore NF. The differences in the NF behavior are believed to relate to the relative sizes of ozonated organic fractions and the NF pores; a similar size of ozonated organic fractions and the NF pores causes significant membrane fouling. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Induction of slow oscillations by rhythmic acoustic stimulation.

PubMed

Ngo, Hong-Viet V; Claussen, Jens C; Born, Jan; Mölle, Matthias

2013-02-01

Slow oscillations are electrical potential oscillations with a spectral peak frequency of ∼0.8 Hz, and hallmark the electroencephalogram during slow-wave sleep. Recent studies have indicated a causal contribution of slow oscillations to the consolidation of memories during slow-wave sleep, raising the question to what extent such oscillations can be induced by external stimulation. Here, we examined whether slow oscillations can be effectively induced by rhythmic acoustic stimulation. Human subjects were examined in three conditions: (i) with tones presented at a rate of 0.8 Hz ('0.8-Hz stimulation'); (ii) with tones presented at a random sequence ('random stimulation'); and (iii) with no tones presented in a control condition ('sham'). Stimulation started during wakefulness before sleep and continued for the first ∼90 min of sleep. Compared with the other two conditions, 0.8-Hz stimulation significantly delayed sleep onset. However, once sleep was established, 0.8-Hz stimulation significantly increased and entrained endogenous slow oscillation activity. Sleep after the 90-min period of stimulation did not differ between the conditions. Our data show that rhythmic acoustic stimulation can be used to effectively enhance slow oscillation activity. However, the effect depends on the brain state, requiring the presence of stable non-rapid eye movement sleep. © 2012 European Sleep Research Society.

Reading strategies of fast and slow readers.

PubMed

Haberlandt, K F; Graesser, A C; Schneider, N J

1989-09-01

In three subject-paced experiments we evaluated reading patterns at the word, line, and sentence level for fast and slow readers. A moving-window method was used to collect word reading times for natural texts. At the word level, reading times of word N were influenced by features of word N-1 for fast readers but not for slow readers. The lag effect exhibited by fast readers indicates that they continue to process a word when it is no longer in view, thus limiting the notion of immediate processing. Contrary to our initial expectation that fast readers would process only a single new argument from a sentence, whereas slow readers would process several new arguments, we found that both reader groups adopted a many-argument strategy. However, fast and slow readers differed in terms of the text units (lines vs. sentences) defining the new-argument effects: Fast readers exhibited greater new-argument effects relative to lines, whereas slow readers exhibited greater new-argument effects relative to sentences. Specifically, slow readers integrated the new arguments primarily at the end of the sentence, whereas fast readers did so at line boundaries. These results are discussed in terms of a buffer-and-integrate model of reading comprehension.

Cerebellar Purkinje Cells Generate Highly Correlated Spontaneous Slow-Rate Fluctuations.

PubMed

Cao, Ying; Liu, Yu; Jaeger, Dieter; Heck, Detlef H

2017-01-01

Cerebellar Purkinje cells (PC) fire action potentials at high, sustained rates. Changes in spike rate that last a few tens of milliseconds encode sensory and behavioral events. Here we investigated spontaneous fluctuations of PC simple spike rate at a slow time scale of the order of 1 s. Simultaneous recordings from pairs of PCs that were aligned either along the sagittal or transversal axis of the cerebellar cortex revealed that simple spike rate fluctuations at the 1 s time scale were highly correlated. Each pair of PCs had either a predominantly positive or negative slow-rate correlation, with negative correlations observed only in PC pairs aligned along the transversal axis. Slow-rate correlations were independent of faster rate changes that were correlated with fluid licking behavior. Simultaneous recordings from PCs and cerebellar nuclear (CN) neurons showed that slow-rate fluctuations in PC and CN activity were also highly correlated, but their correlations continually alternated between periods of positive and negative correlation. The functional significance of this new aspect of cerebellar spike activity remains to be determined. Correlated slow-rate fluctuations seem too slow to be involved in the real-time control of ongoing behavior. However, slow-rate fluctuations of PCs converging on the same CN neuron are likely to modulate the excitability of the CN neuron, thus introduce a possible slow modulation of cerebellar output activity.

Slow Earthquakes in the Alaska-Aleutian Subduction Zone Detected by Multiple Mini Seismic Arrays

NASA Astrophysics Data System (ADS)

LI, B.; Ghosh, A.; Thurber, C. H.; Lanza, F.

2017-12-01

The Alaska-Aleutian subduction zone is one of the most seismically and volcanically active plate boundaries on earth. Compared to other subduction zones, the slow earthquakes, such as tectonic tremors (TTs) and low frequency earthquakes (LFEs), are relatively poorly studied due to the limited data availability and difficult logistics. The analysis of two-months of continuous data from a mini array deployed in 2012 shows abundant tremor and LFE activities under Unalaska Island that is heterogeneously distributed [Li & Ghosh, 2017]. To better study slow earthquakes and understand their physical characteristics in the study region, we deployed a hybrid array of arrays, consisting of three well-designed mini seismic arrays and five stand alone stations, in the Unalaska Island in 2014. They were operational for between one and two years. Using the beam back-projection method [Ghosh et al., 2009, 2012], we detect continuous tremor activities for over a year when all three arrays are running. The sources of tremors are located south of the Unalaska and Akutan Islands, at the eastern and down-dip edge of the rupture zone of the 1957 Mw 8.6 earthquake, and they are clustered in several patches, with a gap between the two major clusters. Tremors show multiple migration patterns with propagation in both along-strike and dip directions and a wide range of velocities. We also identify tens of LFE families and use them as templates to search for repeating LFE events with the matched-filter method. Hundreds to thousands of LFEs for each family are detected and their activities are spatiotemporally consistent with tremor activities. The array techniques are revealing a near-continuous tremor activity in this area with remarkable spatiotemporal details. It helps us to better recognize the physical properties of the transition zone, provides new insights into the slow earthquake activities in this area, and explores their relation with the local earthquakes and the potential slow slip events.

"Slow-scanning" in Ground-based Mid-infrared Observations

NASA Astrophysics Data System (ADS)

Ohsawa, Ryou; Sako, Shigeyuki; Miyata, Takashi; Kamizuka, Takafumi; Okada, Kazushi; Mori, Kiyoshi; Uchiyama, Masahito S.; Yamaguchi, Junpei; Fujiyoshi, Takuya; Morii, Mikio; Ikeda, Shiro

2018-04-01

Chopping observations with a tip-tilt secondary mirror have conventionally been used in ground-based mid-infrared observations. However, it is not practical for next generation large telescopes to have a large tip-tilt mirror that moves at a frequency larger than a few hertz. We propose an alternative observing method, a "slow-scanning" observation. Images are continuously captured as movie data, while the field of view is slowly moved. The signal from an astronomical object is extracted from the movie data by a low-rank and sparse matrix decomposition. The performance of the "slow-scanning" observation was tested in an experimental observation with Subaru/COMICS. The quality of a resultant image in the "slow-scanning" observation was as good as in a conventional chopping observation with COMICS, at least for a bright point-source object. The observational efficiency in the "slow-scanning" observation was better than that in the chopping observation. The results suggest that the "slow-scanning" observation can be a competitive method for the Subaru telescope and be of potential interest to other ground-based facilities to avoid chopping.

Pulsed rotating supersonic source for merged molecular beams

NASA Astrophysics Data System (ADS)

Sheffield, Les; Hickey, Mark; Krasovitskiy, Vitaliy; Rathnayaka, Daya; Lyuksyutov, Igor; Herschbach, Dudley

2012-10-01

We continue the characterization of a pulsed rotating supersonic beam source. The original device was described by M. Gupta and D. Herschbach, J. Phys. Chem. A 105, 1626 (2001). The beam emerges from a nozzle near the tip of a hollow rotor which can be spun at high-speed to shift the molecular velocity distribution downward or upward over a wide range. Here we consider mostly the slowing mode. Introducing a pulsed gas inlet system, and a shutter gate eliminate the main handicap of the original device in which continuous gas flow imposed high background pressure. The new version provides intense pulses, of duration 0.1--0.6 ms (depending on rotor speed) and containing ˜10^12 molecules at lab speeds as low as 35 m/s and ˜10^15 molecules at 400 m/s. Beams of any molecule available as a gas can be slowed (or speeded); e.g., we have produced slow and fast beams of rare gases, O2, NO2, NH3, and SF6. For collision experiments, the ability to scan the beam speed by merely adjusting the rotor is especially advantageous when using two merged beams. By closely matching the beam speeds, very low relative collision energies can be attained without making either beam very slow.

NCL-02: Nanomedicine Pharmacokinetics in Rats Evaluated by SITUA | Frederick National Laboratory for Cancer Research

Cancer.gov

The Nanotechnology Characterization Laboratory will evaluate the pharmacokinetics of a nanoparticulate formulation in rats using a novel stable isotope tracer ultrafiltration assay (SITUA) developed at thelaboratory. The SITUA is a method to fr

Evaluation of the Effectiveness of Using Alfalfa and Buffalo Grass for Remediation of Trichloroethylene from Groundwater

DTIC Science & Technology

1998-06-03

Defense Environmental Restoration Account (DERA) funds provided by Humans Systems Center, Occupational and Environmental Health Directorate...ultrafiltration/ microfiltration , (3) freeze crystallization, (4) membrane prevaporation and (5) reverse osmosis. Sprinkler Irrigation. Wastewater is distributed

Design and characterization of a new bioreactor for continuous ultra-slow uniaxial distraction of a three-dimensional scaffold-free stem cell culture.

PubMed

Weiss, S; Henle, P; Roth, W; Bock, R; Boeuf, S; Richter, W

2011-01-01

A computer controlled dynamic bioreactor for continuous ultra-slow uniaxial distraction of a scaffold-free three-dimensional (3D) mesenchymal stem cell pellet culture was designed to investigate the influence of stepless tensile strain on behavior of distinct primary cells like osteoblasts, chondroblasts, or stem cells without the influence of an artificial culture matrix. The main advantages of this device include the following capabilities: (1) Application of uniaxial ultra-slow stepless distraction within a range of 0.5-250 μm/h and real-time control of the distraction distance with high accuracy (mean error -3.4%); (2) tension strain can be applied on a 3D cell culture within a standard CO(2) -incubator without use of an artificial culture matrix; (3) possibility of histological investigation without loss of distraction; (4) feasibility of molecular analysis on RNA and protein level. This is the first report on a distraction device capable of applying continuous tensile strain to a scaffold-free 3D cell culture within physiological ranges of motion comparable to distraction ostegenesis in vivo. We expect the newly designed microdistraction device to increase our understanding on the regulatory mechanisms of mechanical strains on the metabolism of stem cells. Copyright © 2010 American Institute of Chemical Engineers (AIChE).

Epileptic encephalopathy with continuous spike-waves during sleep: the need for transition from childhood to adulthood medical care appears to be related to etiology.

PubMed

de Saint-Martin, Anne; Rudolf, Gabrielle; Seegmuller, Caroline; Valenti-Hirsch, Maria Paola; Hirsch, Edouard

2014-08-01

Epileptic encephalopathy with continuous diffuse spike-waves during slow-wave sleep (ECSWS) presents clinically with infrequent nocturnal focal seizures, atypical absences related to secondary bilateral synchrony, negative myoclonia, and atonic and rare generalized tonic-clonic seizures. The unique electroencephalography (EEG) pattern found in ECSWS consists of continuous, diffuse, bilateral spike-waves during slow-wave sleep. Despite the eventual disappearance of clinical seizures and EEG abnormalities by adolescence, the prognosis is guarded in most cases because of neuropsychological and behavioral deficits. ECSWS has a heterogeneous etiology (genetic, structural, and unknown). Because epilepsy and electroencephalography (EEG) abnormalities in epileptic encephalopathy with continuous diffuse spike-waves during slow-wave sleep (ECSWS) are self-limited and age related, the need for ongoing medical care and transition to adult care might be questioned. For adolescents in whom etiology remains unknown (possibly genetic) and who experience the disappearance of seizures and EEG abnormalities, there is rarely need for long-term neurologic follow-up, because often a relatively normal cognitive and social evolution follows. However, the majority of patients with structural and possibly "genetic syndromic" etiologies will have persistent cognitive deficits and will need suitable socioeducative care. Therefore, the transition process in ECSWS will depend mainly on etiology and its related features (epileptic active phase duration, and cognitive and behavioral evolution) and revolve around neuropsychological and social support rather than medical and pharmacologic follow-up. Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.

Focal mechanisms and inter-event times of low-frequency earthquakes reveal quasi-continuous deformation and triggered slow slip on the deep Alpine Fault

NASA Astrophysics Data System (ADS)

Baratin, Laura-May; Chamberlain, Calum J.; Townend, John; Savage, Martha K.

2018-02-01

Characterising the seismicity associated with slow deformation in the vicinity of the Alpine Fault may provide constraints on the stresses acting on a major transpressive margin prior to an anticipated great (≥M8) earthquake. Here, we use recently detected tremor and low-frequency earthquakes (LFEs) to examine how slow tectonic deformation is loading the Alpine Fault late in its typical ∼300-yr seismic cycle. We analyse a continuous seismic dataset recorded between 2009 and 2016 using a network of 10-13 short-period seismometers, the Southern Alps Microearthquake Borehole Array. Fourteen primary LFE templates are used in an iterative matched-filter and stacking routine, allowing the detection of similar signals corresponding to LFE families sharing common locations. This yields an 8-yr catalogue containing 10,000 LFEs that are combined for each of the 14 LFE families using phase-weighted stacking to produce signals with the highest possible signal-to-noise ratios. We show that LFEs occur almost continuously during the 8-yr study period and highlight two types of LFE distributions: (1) discrete behaviour with an inter-event time exceeding 2 min; (2) burst-like behaviour with an inter-event time below 2 min. We interpret the discrete events as small-scale frequent deformation on the deep extent of the Alpine Fault and LFE bursts (corresponding in most cases to known episodes of tremor or large regional earthquakes) as brief periods of increased slip activity indicative of slow slip. We compute improved non-linear earthquake locations using a 3-D velocity model. LFEs occur below the seismogenic zone at depths of 17-42 km, on or near the hypothesised deep extent of the Alpine Fault. The first estimates of LFE focal mechanisms associated with continental faulting, in conjunction with recurrence intervals, are consistent with quasi-continuous shear faulting on the deep extent of the Alpine Fault.

Cyclic ethanol metabolism in hypophysectomized rats continuously infused alcohol-containing diets

USDA-ARS?s Scientific Manuscript database

Chronic ethanol (EtOH) intake induces hepatic alcohol dehydrogenase (ADH) expression via disruption of insulin signaling in liver (JBC 2006; 281:1126-34). Total enteral nutrition (TEN) is a method of slow and continuous (approx. 23/day) feeding patients through an intragastric tube. Rats fed EtOH-co...

Exact nonlinear model reduction for a von Kármán beam: Slow-fast decomposition and spectral submanifolds

NASA Astrophysics Data System (ADS)

Jain, Shobhit; Tiso, Paolo; Haller, George

2018-06-01

We apply two recently formulated mathematical techniques, Slow-Fast Decomposition (SFD) and Spectral Submanifold (SSM) reduction, to a von Kármán beam with geometric nonlinearities and viscoelastic damping. SFD identifies a global slow manifold in the full system which attracts solutions at rates faster than typical rates within the manifold. An SSM, the smoothest nonlinear continuation of a linear modal subspace, is then used to further reduce the beam equations within the slow manifold. This two-stage, mathematically exact procedure results in a drastic reduction of the finite-element beam model to a one-degree-of freedom nonlinear oscillator. We also introduce the technique of spectral quotient analysis, which gives the number of modes relevant for reduction as output rather than input to the reduction process.

Committee Report: Metrics & Methods for MF/UF System Optimization

EPA Science Inventory

After a membrane filtration (i.e., microfiltration (MF) and ultrafiltration (UF)) system is designed, installed, and commissioned, it is essential that the plant is well-maintained in order to proactively identify potential design or equipment problems and ensure its proper opera...

EPA Technology Available for Licensing: Portable Device to Concentrate Water Samples for Microorganism Analysis

EPA Pesticide Factsheets

Using a computer controlled system, this ultrafiltration device automates the process of concentrating a water sample and can be operated in the field. The system was also designed to reduce human exposure to potentially contaminated water.

Concentration and Quantification of Somatic and F+ Coliphage from Recreational Waters

EPA Science Inventory

Somatic and F+ coliphages are promising alternative fecal indicators, but current detection methods are hindered by lower levels of coliphages in surface waters compared to traditional bacterial fecal indicators. We evaluated the ability of dead-end hollow fiber ultrafiltration (...

ZENON ENVIRONMENTAL INC., ZENOGEM™ BIOLOGICAL AND ULTRAFILTRATION TECHNOLOGY; INNOVATIVE TECHNOLOGY EVALUATION REPORT

EPA Science Inventory

This report summarizes the results of a field demonstration conducted under the SITE Program. The technology which was demonstrated was a wastewater treatment technology developed by Zenon Environmental Inc. The process, named ZenoGem™, integrates biological treatment with memb...

EMERGING TECHNOLOGY BULLETIN: NEW JERSEY INSTITUTE OF TECHNOLOGY - GHEA ASSOCIATES PROCESS

EPA Science Inventory

The GHEA Associates process applies surfactants and additives to soil washing and wastewater treatment to make organic and metal contaminants soluble (figure 1). The process components include a 25-gal extractor, solid liquid separation, rinse, mixer-settler, and ultrafiltration ...

UTILIZATION OF CHEESE WHEY FOR WINE PRODUCTION

EPA Science Inventory

Wine was successfully produced in the laboratory from cheese whey. The method used involves the deproteinization of either sweet (cheddar cheese) whey or acid (cottage cheese) whey by heat or ultrafiltration, the addition of sulfur dioxide to stabilize the whey by Kruyveromyces f...

Design of a Slowed-Rotor Compound Helicopter for Future Joint Service Missions

DTIC Science & Technology

2010-01-01

achieves a 208kt top speed at engine MCP and 11,000ft/ISA while having 216hp/ton installed power, based on engine MRP and MTOW. Figure 33...Intermediate rated power ISA International Standard Atmosphere MCP Maximum continuous power MRP Maximum rated power MTOW Maximum Takeoff Weight NDARC...NASA Design and Analysis of Rotorcraft SFC Specific fuel consumption SRC Slowed-Rotor Compound Symbols σ Rotor solidity (geometric) CD Drag

Tannins from Hamamelis virginiana bark extract: characterization and improvement of the antiviral efficacy against influenza A virus and human papillomavirus.

PubMed

Theisen, Linda L; Erdelmeier, Clemens A J; Spoden, Gilles A; Boukhallouk, Fatima; Sausy, Aurélie; Florin, Luise; Muller, Claude P

2014-01-01

Antiviral activity has been demonstrated for different tannin-rich plant extracts. Since tannins of different classes and molecular weights are often found together in plant extracts and may differ in their antiviral activity, we have compared the effect against influenza A virus (IAV) of Hamamelis virginiana L. bark extract, fractions enriched in tannins of different molecular weights and individual tannins of defined structures, including pseudotannins. We demonstrate antiviral activity of the bark extract against different IAV strains, including the recently emerged H7N9, and show for the first time that a tannin-rich extract inhibits human papillomavirus (HPV) type 16 infection. As the best performing antiviral candidate, we identified a highly potent fraction against both IAV and HPV, enriched in high molecular weight condensed tannins by ultrafiltration, a simple, reproducible and easily upscalable method. This ultrafiltration concentrate and the bark extract inhibited early and, to a minor extent, later steps in the IAV life cycle and tannin-dependently inhibited HPV attachment. We observed interesting mechanistic differences between tannin structures: High molecular weight tannin containing extracts and tannic acid (1702 g/mol) inhibited both IAV receptor binding and neuraminidase activity. In contrast, low molecular weight compounds (<500 g/mol) such as gallic acid, epigallocatechin gallate or hamamelitannin inhibited neuraminidase but not hemagglutination. Average molecular weight of the compounds seemed to positively correlate with receptor binding (but not neuraminidase) inhibition. In general, neuraminidase inhibition seemed to contribute little to the antiviral activity. Importantly, antiviral use of the ultrafiltration fraction enriched in high molecular weight condensed tannins and, to a lesser extent, the unfractionated bark extract was preferable over individual isolated compounds. These results are of interest for developing and improving plant-based antivirals.

NMR-based metabolite profiling of human milk: A pilot study of methods for investigating compositional changes during lactation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Junfang; Domellöf, Magnus; Zivkovic, Angela M.

Low-molecular-weight metabolites in human milk are gaining increasing interest in studies of infant nutrition. In the present study, the milk metabolome from a single mother was explored at different stages of lactation. Metabolites were extracted from sample aliquots using either methanol/water (MeOH/H{sub 2}O) extraction or ultrafiltration. Nuclear magnetic resonance (NMR) spectroscopy was used for metabolite identification and quantification, and multi- and univariate statistical data analyses were used to detect changes over time of lactation. Compared to MeOH/H{sub 2}O extraction, ultrafiltration more efficiently reduced the interference from lipid and protein resonances, thereby enabling the identification and quantification of 36 metabolites. Themore » human milk metabolomes at the early (9–24 days after delivery) and late (31–87 days after delivery) stages of lactation were distinctly different according to multi- and univariate statistics. The late lactation stage was characterized by significantly elevated concentrations of lactose, choline, alanine, glutamate, and glutamine, as well as by reduced levels of citrate, phosphocholine, glycerophosphocholine, and N-acetylglucosamine. Our results indicate that there are significant compositional changes of the human milk metabolome also in different phases of the matured lactation stage. These findings complement temporal studies on the colostrum and transitional metabolome in providing a better understanding of the nutritional variations received by an infant. - Highlights: • 36 metabolites were simultaneously quantified in human milk by NMR. • Ultrafiltration more efficiently reduces interferences than MeOH/H{sub 2}O extraction. • Compositional changes of the human milk exist during the matured lactation stage.« less

Removal of trace organic chemicals and performance of a novel hybrid ultrafiltration-osmotic membrane bioreactor.

PubMed

Holloway, Ryan W; Regnery, Julia; Nghiem, Long D; Cath, Tzahi Y

2014-09-16

A hybrid ultrafiltration-osmotic membrane bioreactor (UFO-MBR) was investigated for over 35 days for nutrient and trace organic chemical (TOrC) removal from municipal wastewater. The UFO-MBR system uses both ultrafiltration (UF) and forward osmosis (FO) membranes in parallel to simultaneously extract clean water from an activated sludge reactor for nonpotable (or environmental discharge) and potable reuse, respectively. In the FO stream, water is drawn by osmosis from activated sludge through an FO membrane into a draw solution (DS), which becomes diluted during the process. A reverse osmosis (RO) system is then used to reconcentrate the diluted DS and produce clean water suitable for direct potable reuse. The UF membrane extracts water, dissolved salts, and some nutrients from the system to prevent their accumulation in the activated sludge of the osmotic MBR. The UF permeate can be used for nonpotable reuse purposes (e.g., irrigation and toilet flushing). Results from UFO-MBR investigation illustrated that the chemical oxygen demand, total nitrogen, and total phosphorus removals were greater than 99%, 82%, and 99%, respectively. Twenty TOrCs were detected in the municipal wastewater that was used as feed to the UFO-MBR system. Among these 20 TOrCs, 15 were removed by the hybrid UFO-MBR system to below the detection limit. High FO membrane rejection was observed for all ionic and nonionic hydrophilic TOrCs and lower rejection was observed for nonionic hydrophobic TOrCs. With the exceptions of bisphenol A and DEET, all TOrCs that were detected in the DS were well rejected by the RO membrane. Overall, the UFO-MBR can operate sustainably and has the potential to be utilized for direct potable reuse applications.

High concentration biotherapeutic formulation and ultrafiltration: Part 1 pressure limits.

PubMed

Lutz, Herb; Arias, Joshua; Zou, Yu

2017-01-01

High therapeutic dosage requirements and the desire for ease of administration drive the trend to subcutaneous administration using delivery systems such as subcutaneous pumps and prefilled syringes. Because of dosage volume limits, prefilled syringe administration requires higher concentration liquid formulations, limited to about 30 cP or roughly 100-300 g L -1 for mAb's. Ultrafiltration (UF) processes are routinely used to formulate biological therapeutics. This article considers pressure constraints on the UF process that may limit its ability to achieve high final product concentrations. A system hardware analysis shows that the ultrafiltration cassette pressure drop is the major factor limiting UF systems. Additional system design recommendations are also provided. The design and performance of a new cassette with a lower feed channel flow resistance is described along with 3D modeling of feed channel pressure drop. The implications of variations in cassette flow channel resistance for scaling up and setting specifications are considered. A recommendation for a maximum pressure specification is provided. A review of viscosity data and theory shows that molecular engineering, temperature, and the use of viscosity modifying excipients including pH adjustment can be used to achieve higher concentrations. The combined use of a low pressure drop cassette with excipients further increased final concentrations by 35%. Guidance is provided on system operation to control hydraulics during final concentration. These recommendations should allow one to design and operate systems to routinely achieve the 30 cP target final viscosity capable of delivery using a pre-filled syringe. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:113-124, 2017. © 2016 American Institute of Chemical Engineers.

Bicarbonate buffered peritoneal dialysis fluid upregulates angiopoietin-1 and promotes vessel maturation.

PubMed

Eich, Gwendolyn; Bartosova, Maria; Tischer, Christian; Wlodkowski, Tanja Tamara; Schaefer, Betti; Pichl, Sebastian; Kraewer, Nicole; Ranchin, Bruno; Vondrak, Karel; Liebau, Max Christoph; Hackert, Thilo; Schmitt, Claus Peter

2017-01-01

Ultrafiltration decline is a progressive issue for patients on chronic peritoneal dialysis (PD) and can be caused by peritoneal angiogenesis induced by PD fluids. A recent pediatric trial suggests better preservation of ultrafiltration with bicarbonate versus lactate buffered fluid; underlying molecular mechanisms are unknown. Angiogenic cytokine profile, tube formation capacity and Receptor Tyrosine Kinase translocation were assessed in primary human umbilical vein endothelial cells following incubation with bicarbonate (BPDF) and lactate buffered (LPDF), pH neutral PD fluid with low glucose degradation product content and lactate buffered, acidic PD fluid with high glucose degradation product content (CPDF). Peritoneal biopsies from age-, PD-vintage- and dialytic glucose exposure matched, peritonitis-free children on chronic PD underwent automated histomorphometry and immunohistochemistry. In endothelial cells angiopoietin-1 mRNA and protein abundance increased 200% upon incubation with BPDF, but decreased by 70% with LPDF as compared to medium control; angiopoietin-2 remained unchanged. Angiopoietin-1/Angiopoietin-2 protein ratio was 15 and 3-fold increased with BPDF compared to LPDF and medium. Time-lapse microscopy with automated network analysis demonstrated less endothelial cell tube formation with BPDF compared to LPDF and CPDF incubation. Receptor Tyrosine Kinase translocated to the cell membrane in BPDF but not in LPDF or CPDF incubated endothelial cells. In children dialyzed with BPDF peritoneal vessels were larger and angiopoietin-1 abundance in CD31 positive endothelium higher compared to children treated with LPDF. Bicarbonate buffered PD fluid promotes vessel maturation via upregulation of angiopoietin-1 in vitro and in children on dialysis. Our findings suggest a molecular mechanism for the observed superior preservation of ultrafiltration capacity with bicarbonate buffered PD fluid with low glucose degradation product content.

Mixed Matrix PVDF Membranes With in Situ Synthesized PAMAM Dendrimer-Like Particles: A New Class of Sorbents for Cu(II) Recovery from Aqueous Solutions by Ultrafiltration.

PubMed

Kotte, Madhusudhana Rao; Kuvarega, Alex T; Cho, Manki; Mamba, Bhekie B; Diallo, Mamadou S

2015-08-18

Advances in industrial ecology, desalination, and resource recovery have established that industrial wastewater, seawater, and brines are important and largely untapped sources of critical metals and elements. A Grand Challenge in metal recovery from industrial wastewater is to design and synthesize high capacity, recyclable and robust chelating ligands with tunable metal ion selectivity that can be efficiently processed into low-energy separation materials and modules. In our efforts to develop high capacity chelating membranes for metal recovery from impaired water, we report a one-pot method for the preparation of a new family of mixed matrix polyvinylidene fluoride (PVDF) membranes with in situ synthesized poly(amidoamine) [PAMAM] particles. The key feature of our new membrane preparation method is the in situ synthesis of PAMAM dendrimer-like particles in the dope solutions prior to membrane casting using low-generation dendrimers (G0 and G1-NH2) with terminal primary amine groups as precursors and epichlorohydrin (ECH) as cross-linker. By using a combined thermally induced phase separation (TIPS) and nonsolvent induced phase separation (NIPS) casting process, we successfully prepared a new family of asymmetric PVDF ultrafiltration membranes with (i) neutral and hydrophilic surface layers of average pore diameters of 22-45 nm, (ii) high loadings (∼48 wt %) of dendrimer-like PAMAM particles with average diameters of ∼1.3-2.4 μm, and (iii) matrices with sponge-like microstructures characteristics of membranes with strong mechanical integrity. Preliminary experiments show that these new mixed matrix PVDF membranes can serve as high capacity sorbents for Cu(II) recovery from aqueous solutions by ultrafiltration.

Tangential flow ultrafiltration for detection of white spot syndrome virus (WSSV) in shrimp pond water.

PubMed

Alavandi, S V; Ananda Bharathi, R; Satheesh Kumar, S; Dineshkumar, N; Saravanakumar, C; Joseph Sahaya Rajan, J

2015-06-15

Water represents the most important component in the white spot syndrome virus (WSSV) transmission pathway in aquaculture, yet there is very little information. Detection of viruses in water is a challenge, since their counts will often be too low to be detected by available methods such as polymerase chain reaction (PCR). In order to overcome this difficulty, viruses in water have to be concentrated from large volumes of water prior to detection. In this study, a total of 19 water samples from aquaculture ecosystem comprising 3 creeks, 10 shrimp culture ponds, 3 shrimp broodstock tanks and 2 larval rearing tanks of shrimp hatcheries and a sample from a hatchery effluent treatment tank were subjected to concentration of viruses by ultrafiltration (UF) using tangential flow filtration (TFF). Twenty to 100l of water from these sources was concentrated to a final volume of 100mL (200-1000 fold). The efficiency of recovery of WSSV by TFF ranged from 7.5 to 89.61%. WSSV could be successfully detected by PCR in the viral concentrates obtained from water samples of three shrimp culture ponds, one each of the shrimp broodstock tank, larval rearing tank, and the shrimp hatchery effluent treatment tank with WSSV copy numbers ranging from 6 to 157mL(-1) by quantitative real time PCR. The ultrafiltration virus concentration technique enables efficient detection of shrimp viral pathogens in water from aquaculture facilities. It could be used as an important tool to understand the efficacy of biosecurity protocols adopted in the aquaculture facility and to carry out epidemiological investigations of aquatic viral pathogens. Copyright © 2015 Elsevier B.V. All rights reserved.

The removal of organic precursors of DBPs during three advanced water treatment processes including ultrafiltration, biofiltration, and ozonation.

PubMed

Zha, Xiao-Song; Ma, Lu-Ming; Wu, Jin; Liu, Yan

2016-08-01

The removal efficiency of organic matter, the formation potential of trihalomethanes (THMFP), and the formation potential of haloacetic acids (HAAFP) in each unit of three advanced treatment processes were investigated in this paper. The molecular weight distribution and the components of organic matter in water samples were also determined to study the transformation of organic matter during these advanced treatments. Low-molecular-weight matter was the predominant fraction in raw water, and it could not be removed effectively by ultrafiltration and biofiltration. The dominant species of disinfection by-product formation potential (DBPFP) in raw water were chloroform and monochloroacetic acid (MCAA), with average concentrations of 107.3 and 125.9 μg/L, respectively. However, the formation potential of chloroform and MCAA decreased to 36.2 and 11.5 μg/L after ultrafiltration. Similarly, biological pretreatment obtained high removal efficiency for DBPFP. The total THMFP decreased from 173.8 to 81.8 μg/L, and the total HAAFP decreased from 211.9 to 84.2 μg/L. Separate ozonation had an adverse effect on DBPFP, especially for chlorinated HAAFP. Numerous low-molecular-weight compounds such as aldehydes, ketones, and alcohols were generated during the ozonation, which have been proven to be important precursors of HAAs. However, the ozonation/biological activated carbon (BAC) combined process had a better removal efficiency for DBPFP. The total DBPFP decreased remarkably from 338.7 to 113.3 μg/L after the O3/BAC process, far below the separated BAC of process B (189.1 μg/L).

Isolation and partial characterization of melanoma-associated antigens identified by autologous antibody.

PubMed

Vlock, D R; Scalise, D; Meglin, N; Kirkwood, J M; Ballou, B

1988-06-01

The study of the autologous immune response to cancer avoids the difficulties encountered in the use of xenoantisera and may identify antigens of physiological relevance. However, the low titer and incidence of autologous antibody to melanoma have hampered further evaluation. By utilizing acid dissociation and ultrafiltration of serum, we have been able to augment the detectable autologous immune response to melanoma in the majority of patients studied. In autologous system Y-Mel 84:420, serum S150 demonstrated a rise in titer from 1:32 in native sera to 1:262,044 after dissociation. The antigen detected by S150 was found to be broadly represented on melanoma, glioma, renal cell carcinoma, neuroblastoma, and head and neck carcinoma cell lines. It did not react with bladder or colon carcinoma, fetal fibroblasts, pooled platelets, lymphocytes and red blood cells, or autologous cultured lymphocytes. Using polyacrylamide gel electrophoresis, S150 detects a 66,000-mol wt antigen in spent tissue culture media and serum ultrafiltrate. In cell lysate two bands between 20,000 and 30,000 mol wt are detected by S150. The 66,000-mol wt antigen is sensitive to trypsin digestion and but is resistant to pepsin and heat inactivation. Exposure of spent media to trypsin results in the development of a 24,000-mol wt band that appears to correspond to the antigen detected in the cell lysate. The difference between the antigens detected in the cell lysate as compared with spent media and serum ultrafiltrate may be due to degradation during cell lysis. We conclude that melanoma-associated antigens are present in the serum of patients with melanoma and are shed or secreted by their tumor cells.

Tannins from Hamamelis virginiana Bark Extract: Characterization and Improvement of the Antiviral Efficacy against Influenza A Virus and Human Papillomavirus

PubMed Central

Theisen, Linda L.; Erdelmeier, Clemens A. J.; Spoden, Gilles A.; Boukhallouk, Fatima; Sausy, Aurélie; Florin, Luise; Muller, Claude P.

2014-01-01

Antiviral activity has been demonstrated for different tannin-rich plant extracts. Since tannins of different classes and molecular weights are often found together in plant extracts and may differ in their antiviral activity, we have compared the effect against influenza A virus (IAV) of Hamamelis virginiana L. bark extract, fractions enriched in tannins of different molecular weights and individual tannins of defined structures, including pseudotannins. We demonstrate antiviral activity of the bark extract against different IAV strains, including the recently emerged H7N9, and show for the first time that a tannin-rich extract inhibits human papillomavirus (HPV) type 16 infection. As the best performing antiviral candidate, we identified a highly potent fraction against both IAV and HPV, enriched in high molecular weight condensed tannins by ultrafiltration, a simple, reproducible and easily upscalable method. This ultrafiltration concentrate and the bark extract inhibited early and, to a minor extent, later steps in the IAV life cycle and tannin-dependently inhibited HPV attachment. We observed interesting mechanistic differences between tannin structures: High molecular weight tannin containing extracts and tannic acid (1702 g/mol) inhibited both IAV receptor binding and neuraminidase activity. In contrast, low molecular weight compounds (<500 g/mol) such as gallic acid, epigallocatechin gallate or hamamelitannin inhibited neuraminidase but not hemagglutination. Average molecular weight of the compounds seemed to positively correlate with receptor binding (but not neuraminidase) inhibition. In general, neuraminidase inhibition seemed to contribute little to the antiviral activity. Importantly, antiviral use of the ultrafiltration fraction enriched in high molecular weight condensed tannins and, to a lesser extent, the unfractionated bark extract was preferable over individual isolated compounds. These results are of interest for developing and improving plant-based antivirals. PMID:24498245

Effect of Mannitol on Glomerular Ultrafiltration in the Hydropenic Rat

PubMed Central

Blantz, Roland C.

1974-01-01

The effect of mannitol upon glomerular ultrafiltration was examined in hydropenic Munich-Wistar rats. Superficial nephron filtration rate (sngfr) rose from 32.0±0.9 nl/min/g kidney wt to 42.0±1.6 (P < 0.001) in eight rats. Hydrostatic pressure gradients acting across the glomerular capillary (ΔP) were measured in glomerular capillaries and Bowman's space with a servo-nulling device, systemic (πA) and efferent arteriolar oncotic pressures (πE) were determined by microprotein analysis. These data were applied to a computer-based mathematical model of glomerular ultrafiltration to determine the profile of effective filtration pressure (EFP = ΔP — π) and total glomerular permeability (LpA) in both states. Filtration equilibrium obtained in hydropenia (LpA ≥ 0.099±0.006 nl/s/g kidney wt/mm Hg) and sngfr rose because EFP increased from a maximum value of 4.2±1.1 to 12.8±0.5 mm Hg after mannitol (P <0.01). This increase was due to both increased nephron plasma flow and decreased πA. Computer analysis of these data revealed that more than half (>58%) of this increase was due to decreased πA, consequent to dilution of protein. Since EFP was disequilibrated after mannitol, LpA could be calculated accurately (0.065 ± 0.003 nl/s/g kidney wt/mm Hg) and was significantly lower than the minimum estimate in hydropenia. Therefore, sngfr does increase with mannitol and this increase is not wholly dependent upon an increase in nephron plasma flow since the major factor increasing EFP was decreased πA. PMID:4418509

Protein binding and its potential for eliciting minimal systemic side effects with a novel inhaled corticosteroid, ciclesonide.

PubMed

Rohatagi, Shashank; Luo, Yongyi; Shen, Liduo; Guo, Zuyu; Schemm, Christina; Huang, Yongqing; Chen, Kelly; David, Michael; Nave, Ruediger; King, S Peter

2005-01-01

Freely circulating, protein unbound, active inhaled corticosteroid (ICS) can cause systemic adverse effects. Desisobutyryl-ciclesonide (des-CIC) is the active metabolite of ciclesonide, an effective, novel ICS for persistent asthma. This study examines the free fraction of ciclesonide and des-CIC and determines whether the presence of other agents or disease states affects protein binding. Protein binding of des-CIC (0.5, 5.0, 25, 100, and 500 ng/mL) was determined, using both equilibrium dialysis and ultrafiltration, in plasma from humans (healthy and either renally or hepatically impaired) and several animal species and in the presence of either salicylates or warfarin. Dialyzed samples were analyzed by liquid chromatography with tandem mass spectroscopy to determine both free and bound concentrations of des-CIC. After ultrafiltration, spiked plasma plus H-des-CIC was separated into free and bound fractions by centrifugation and quantified by scintillation counting. Additionally, in another study, protein binding of ciclesonide was determined by equilibrium dialysis. For equilibrium dialysis, the mean percentages of des-CIC (0.5-500 ng/mL) plasma protein binding across species were high, approximately 99%, and no apparent saturation of protein binding was observed. Results were similar for ultrafiltration analysis. Protein binding of des-CIC did not change in the presence of warfarin or salicylates or in the plasma of renally or hepatically impaired patients. The protein binding of ciclesonide was 99.4% in human serum. The very low fraction of unbound des-CIC in the systemic circulation suggests minimal systemic exposure of unbound des-CIC, thus suggesting a low potential for systemic adverse effects after administration of inhaled ciclesonide.

Can sterile and pyrogen-free on-line substitution fluid be routinely delivered? A multicentric study on the microbiological safety of on-line haemodiafiltration.

PubMed

Vaslaki, L; Karátson, A; Vörös, P; Major, L; Pethö, F; Ladányi, E; Weber, C; Mitteregger, R; Falkenhagen, D

2000-01-01

Microbial contamination is characterized not only by the presence of bacteria, but also by high concentrations of biologically active by-products. They are potentially able to cross ultrafiltration and dialysis membranes and stimulate immunocompetent blood cells to synthesize cytokines. In turn, cytokine induction causes acute symptoms and has been incriminated in the long-term complications of haemodialysis patients. Infusion of large volumes of substitution fluids following ultrafiltration of microbially contaminated dialysis fluids may place patients on on-line therapies at particular risk. In this study we evaluated 30 machines with a two-stage ultrafiltration system in routine clinical haemodiafiltration settings in six centres for 6 months. Microbiological safety was assessed monthly and at the last use of the filters by determining microbial counts, endotoxin concentration and cytokine-inducing activity. No pyrogenic episodes were observed during the study period. Double-filtration of standard dialysis fluid (range, <1-895 cfu/ml, 0.0028-4.6822 IU/ml) resulted in sterile substitution fluids with endotoxin concentrations well below the Ph.Eur. standard for haemofiltration solutions (range, 0.0014-0.0281 vs 0.25 IU/ml). Moreover, they did not differ from commercial haemofiltration solutions and depyrogenated saline. Likewise, there was no difference in the cytokine-inducing activity between the solutions tested. The high microbiological quality of the ultrafiltered dialysis fluid, which was in the same range as substitution fluid, translates into both the absence of cytokine induction by dialyser back-transport and a redundant safety mode of the on-line system by a second filtration step. On-line HDF treatment can routinely be provided with ultra-pure dialysis fluids and sterile substitution fluids at pyrogen-free levels. The online preparation of substitution fluids thus can be considered microbiologically safe.

The longitudinal effects of peritonitis on peritoneal membrane function
.

PubMed

Sia, Christopher S B; Paul, Eldho; Tregaskis, Peter; Walker, Rowan G; Wilson, Scott G

2017-12-01

The longitudinal effects of peritoneal dialysis (PD) peritonitis on small solute clearance and ultrafiltration are controversial. We identified 27 patients with PD peritonitis over a 4-year period at a tertiary hospital. Adequacy tests at an "early" (1 - 3 months), "intermediate" (6 ± 2 months), and a "late" (12 ± 2 months) time period after the episode were compared with a pre-peritonitis baseline. The effect of time on serum albumin, weekly creatinine clearance, Kt/V, and net fluid volume removal was assessed. At 12 months, 16/27 (59.3%) patients were no longer on PD. Ten were transferred to hemodialysis, predominantly due to peritonitis (60%). Five patients died, and 1 received a renal allograft. Total daily fluid volume removal significantly decreased over time with an aggregated mean reduction of 523 mL/day between the baseline and 12-month test (1,624 ± 139 mL vs. 1,101 ± 160 mL; p = 0.02). This was due to an equivalent loss of both ultrafiltration and residual urine output, although the separate decline in these individual parameters was not statistically significant. There was no significant change in Kt/V, creatinine clearance, or serum albumin indicating preserved solute transport in those patients with sustained technique survival post peritonitis. Peritonitis is a common cause for transfer to hemodialysis. Fluid volume removal is the most significantly affected parameter at 12 months post peritonitis, driven by the combination of both ultrafiltration reduction and loss of residual diuresis. Clinicians should be aware that peritonitis identifies patients at high risk for technique failure. These findings should prompt clinicians to closely surveil volume status and consider backup dialytic strategies as early as 12 months post peritonitis.
.

Effect of Neutral-pH, Low–Glucose Degradation Product Peritoneal Dialysis Solutions on Residual Renal Function, Urine Volume, and Ultrafiltration: A Systematic Review and Meta-Analysis

PubMed Central

Yohanna, Seychelle; Alkatheeri, Ali M.A.; Brimble, Scott K.; McCormick, Brendan; Iansavitchous, Arthur; Blake, Peter G.

2015-01-01

Background and objectives Neutral-pH, low–glucose degradation products solutions were developed in an attempt to lessen the adverse effects of conventional peritoneal dialysis solutions. A systematic review was performed evaluating the effect of these solutions on residual renal function, urine volume, peritoneal ultrafiltration, and peritoneal small-solute transport (dialysate to plasma creatinine ratio) over time. Design, setting, participants, & measurements Multiple electronic databases were searched from January of 1995 to January of 2013. Randomized trials reporting on any of four prespecified outcomes were selected by consensus among multiple reviewers. Results Eleven trials of 643 patients were included. Trials were generally of poor quality. The meta-analysis was performed using a random effects model. The use of neutral-pH, low-glucose degradation products solutions resulted in better preserved residual renal function at various study durations, including >1 year (combined analysis: 11 studies; 643 patients; standardized mean difference =0.17 ml/min; 95% confidence interval, 0.01 to 0.32), and greater urine volumes (eight studies; 598 patients; mean difference =128 ml/d; 95% confidence interval, 58 to 198). There was no significant difference in peritoneal ultrafiltration (seven studies; 571 patients; mean difference =−110; 95% confidence interval, −312 to 91) or dialysate to plasma creatinine ratio (six studies; 432 patients; mean difference =0.03; 95% confidence interval, 0.00 to 0.06). Conclusions The use of neutral-pH, low–glucose degradation products solutions results in better preservation of residual renal function and greater urine volumes. The effect on residual renal function occurred early and persisted beyond 12 months. Additional studies are required to evaluate the use of neutral-pH, low–glucose degradation products solutions on hard clinical outcomes. PMID:26048890

The action of water films at Å-scales in the Earth: Implications for the Nankai subduction system

NASA Astrophysics Data System (ADS)

Brown, Kevin M.; Poeppe, Dean; Josh, Matthew; Sample, James; Even, Emilie; Saffer, Demian; Tobin, Harold; Hirose, Takehiro; Kulongoski, J. T.; Toczko, Sean; Maeda, Lena; IODP Expedition 348 Shipboard Party

2017-04-01

Water properties change with confinement within nanofilms trapped between natural charged clay particles. We investigated nanofilm characteristics through high-stress laboratory compression tests in combination with analyses of expelled pore fluids. We utilized sediments obtained from deep drilling of the Nankai subduction zone at Site C0002 of the Integrated Ocean Drilling Program (IODP). We show that below 1-2 km, there should be widespread ultrafiltration of migrating fluids. Experiments to > ∼ 100 MPa normal compression collapse pores below a few ion monofilm thicknesses. A reduction towards a single condensing/dehydrating ion monofilm occurs as stresses rise >100-200 MPa and clay separations are reduced to <10-20 Å. Thus, porosity in high mineral surface area systems only consists of double and single monofilms at depths below a few km leaving little room for either bulk water or the deep biosphere. The resulting semipermeable properties result in variable segregation of ions and charged isotopes and water during active flow. The ultrafiltration and ion dehydration processes are coupled in that both require the partial immobilization of ions between the charged clay surfaces. The general effect is to increase salinities in residual pore fluids at depth and freshen fluids expelled during consolidation. Cessation of nanofilm collapse to a near constant ∼17 Å below 2 km depth at Nankai supports the contention for the onset of substantial geopressuring on the deeper seismogenic fault. The properties of monofilm water, thus, have considerable implications for the deep water properties of subduction zones generating major tremor and Mw 8+ earthquakes. Indeed, the combined effects of advective flow, ultrafiltration, diffusion, and diagenesis could provide a unifying explanation for the origins of overpressuring and pore water geochemical signals observed in many natural systems.

The Effects of Sleep Continuity Disruption on Positive Mood and Sleep Architecture in Healthy Adults

PubMed Central

Finan, Patrick H.; Quartana, Phillip J.; Smith, Michael T.

2015-01-01

Objective: The purpose of this study was to test an experimental model of the effects of sleep continuity disturbance on sleep architecture and positive mood in order to better understand the mechanisms linking insomnia and depression. Design: Participants were randomized to receive 3 consecutive nights of sleep continuity disruption via forced nocturnal awakenings (FA, n = 21), or one of two control conditions: restricted sleep opportunity (RSO, n = 17) or uninterrupted sleep (US, n = 24). Setting: The study was set in an inpatient clinical research suite. Participants: Healthy, good-sleeping men and women were included. Measurement and Results: Polysomnography was used to measure sleep architecture, and mood was assessed via self-report each day. Compared to restricted sleep opportunity controls, forced awakenings subjects had significantly less slow wave sleep (P < 0.05) after the first night of sleep deprivation, and significantly lower positive mood (P < 0.05) after the second night of sleep deprivation. The differential change in slow wave sleep statistically mediated the observed group differences in positive mood (P = 0.002). Conclusions: To our knowledge, this is the first human experimental study to demonstrate that, despite comparable reductions in total sleep time, partial sleep loss from sleep continuity disruption is more detrimental to positive mood than partial sleep loss from delaying bedtime, even when controlling for concomitant increases in negative mood. With these findings, we provide temporal evidence in support of a putative biologic mechanism (slow wave sleep deficit) that could help explain the strong comorbidity between insomnia and depression. Citation: Finan PH, Quartana PJ, Smith MT. The effects of sleep continuity disruption on positive mood and sleep architecture in healthy adults. SLEEP 2015;38(11):1735–1742. PMID:26085289

Calculations of the Electron Energy Distribution Function in a Uranium Plasma by Analytic and Monte Carlo Techniques. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Bathke, C. G.

1976-01-01

Electron energy distribution functions were calculated in a U235 plasma at 1 atmosphere for various plasma temperatures and neutron fluxes. The distributions are assumed to be a summation of a high energy tail and a Maxwellian distribution. The sources of energetic electrons considered are the fission-fragment induced ionization of uranium and the electron induced ionization of uranium. The calculation of the high energy tail is reduced to an electron slowing down calculation, from the most energetic source to the energy where the electron is assumed to be incorporated into the Maxwellian distribution. The pertinent collisional processes are electron-electron scattering and electron induced ionization and excitation of uranium. Two distinct methods were employed in the calculation of the distributions. One method is based upon the assumption of continuous slowing and yields a distribution inversely proportional to the stopping power. An iteration scheme is utilized to include the secondary electron avalanche. In the other method, a governing equation is derived without assuming continuous electron slowing. This equation is solved by a Monte Carlo technique.

Membrane technology for sustainable treated wastewater reuse: agricultural, environmental and hydrological considerations.

PubMed

Oron, Gideon; Gillerman, Leonid; Bick, Amos; Manor, Yossi; Buriakovsky, Nisan; Hagin, Joseph

2008-01-01

Field experiments were conducted in agricultural fields in which secondary wastewater of the City of Arad (Israel) is reused for irrigation. For sustainable agricultural production and safe groundwater recharge the secondary effluent is further polished by a combined two-stage membrane pilot system. The pilot membrane system consists of two main in row stages: Ultrafiltration (UF) and Reverse Osmosis (RO). The UF stage is efficient in the removal of the pathogens and suspended organic matter while the successive RO stage provides safe removal of the dissolved solids (salinity). Effluents of various qualities were applied for agricultural irrigation along with continuous monitoring of the membrane system performance. Best agricultural yields were obtained when applying effluent having minimal content of dissolved solids (after the RO stage) as compared with secondary effluent without any further treatment and extended storage. In regions with shallow groundwater reduced soil salinity in the upper productive layers, maintained by extra membrane treatment, will guarantee minimal dissolved solids migration to the aquifers and minimize salinisation processes. (c) IWA Publishing 2008.

In vitro chemopreventive properties of peptides released from quinoa (Chenopodium quinoa Willd.) protein under simulated gastrointestinal digestion.

PubMed

Vilcacundo, Rubén; Miralles, Beatriz; Carrillo, Wilman; Hernández-Ledesma, Blanca

2018-03-01

Because of the continuous and direct interaction between the digestive tract and foods, dietary compounds represent an interesting source of chemopreventive agents for gastrointestinal health. In this study, the influence of a standardized static in vitro gastrointestinal digestion model on the release of peptides with chemopreventive potential from quinoa protein was investigated. Gastroduodenal digests and fractions collected by ultrafiltration were evaluated for their in plate oxygen radical absorbance capacity and in vitro colon cancer cell viability inhibitory activity. Highest effects were observed in the digests obtained during the intestinal phase, with fraction containing peptides <5kDa as the main responsible for the antioxidant activity and peptides >5kDa showing the greatest anti-cancer effects. Seventeen potential bioactive peptides derived from quinoa proteins have been identified. These proteins might be utilized as new ingredients in the development of functional foods or nutraceuticals with the aim of reducing oxidative stress-associated diseases, including cancer. Copyright © 2017 Elsevier Ltd. All rights reserved.

Whey protein fractionation using supercritical carbon dioxide

USDA-ARS?s Scientific Manuscript database

Sweet whey, a coproduct of the cheesemaking process, can be concentrated using ultrafiltration and ion-exchange to produce whey protein isolates (WPI). WPI contains approximately 32% alpha-lactalbumin (alpha-LA) and 61% beta-lactoglobulin (beta-LG), plus a small amount of minor whey proteins. Whil...

EVALUATION OF ULTRAFILTRATION TO RECOVER AQUEOUS IRON PHOSPHATING/DEGREASING BATH

EPA Science Inventory

Pollution prevention efforts studied in the report summarized here targeted the hazardous waste generated from a 5000-gal iron phosphating/degreasing bath used by a metal fabricator to clean and precondition steel parts for painting. This project was carried out in four stages: (...

A method of chemiluminescence coupled with ultrafiltration for investigating the interaction between ibuprofen and human serum albumin.

PubMed

Xiong, Xunyu; Zhang, Qunzheng; Nan, Yefei; Gu, Xuefan

2013-01-01

In acidic media, ibuprofen substantially enhanced the weak chemiluminescence (CL) produced by sodium sulfite and potassium permanganate. The increased signals were linearly correlated with ibuprofen concentrations ranging from 1.2 × 10(-3) to 4.8 μM, with a detection limit of 4.8 × 10(-4) μM. Two ultrafiltration (UF) membranes were used to construct a unit for trapping 0.15 and 0.75 μM human serum albumin (HSA) and coupled online with the CL system. At low HSA concentrations, the numbers of bound molecules per binding site were calculated to be 0.9 for Sudlow site I and 6.2 for Sudlow site II. The association constants on these binding sites were 5.9 × 10(5) and 3.4 × 10(4) M(-1), respectively. Our CL-UF protocol presents a rapid and sensitive method for studies on drug-protein interaction. Copyright © 2012 John Wiley & Sons, Ltd.

Separation and purification of γ-aminobutyric acid from fermentation broth by flocculation and chromatographic methodologies.

PubMed

Gao, Qiang; Duan, Qiang; Wang, Depei; Zhang, Yunze; Zheng, Chunyang

2013-02-27

To date, the multifunctional γ-aminobutyric acid (GABA) is mainly produced by microbial fermentation in industry. The purpose of this study was to find an effective method for separation and purification of 31.2 g/L initial GABA from the fermentation broth of Enterococcus raffinosus TCCC11660. To remove the impurities from fermentation broth, flocculation pretreatment using chitosan and sodium alginate was first implemented to facilitate subsequent filtration. Ultrafiltration followed two discontinuous diafiltration steps to effectively remove proteins and macromolecular pigments, and the resulting permeate was further decolored by DA201-CII resin at a high decoloration ratio and GABA recovery. Subsequently, ion exchange chromatography (IEC) with Amberlite 200C resin and gradient elution were applied for GABA separation from glutamate and arginine. Finally, GABA crystals of 99.1% purity were prepared via warm ethanol precipitation twice. Overall, our results reveal that the successive process including flocculation, filtration, ultrafiltration, decoloration, IEC, and crystallization is promising for scale-up GABA extraction from fermentation broth.

Effects of endogenous small molecular compounds on the rheological properties, texture and microstructure of soymilk coagulum: Removal of phytate using ultrafiltration.

PubMed

Wang, Ruican; Guo, Shuntang

2016-11-15

This study aims to clarify the roles played by endogenous small molecular components in soymilk coagulation process and the properties of gels. Soymilk samples with decreasing levels of small molecules were prepared by ultrafiltration, to reduce the amount of phytate and salts. CaSO4-induced coagulation process was analyzed using rheological methods. Results showed that removal of free small molecules decreased the activation energy of protein coagulation, resulting in accelerated reaction and increased gel strength. However, too fast a reaction led to the drop in storage modulus (G'). Microscopic observation suggested that accelerated coagulation generated a coarse and non-uniform gel network with large pores. This network could not hold much water, leading to serious syneresis. Endogenous small molecules in soymilk were vital in the fine gel structure. Coagulation rate could be controlled by adjusting the amount of small molecules to obtain tofu products with the optimal texture. Copyright © 2016 Elsevier Ltd. All rights reserved.

Identification of tyrosinase specific inhibitors from Xanthium strumarium fruit extract using ultrafiltration-high performance liquid chromatography.

PubMed

Wang, Zhiqiang; Hwang, Seung Hwan; Huang, Bo; Lim, Soon Sung

2015-10-01

In this study, a strategy based on ultrafiltration-high performance liquid chromatography coupled with diode array detection (UF-HPLC-DAD) was proposed for screening tyrosinase specific inhibitors in Xanthii fructus. The false negatives were distinguished by optimizing the UF-HPLC-DAD parameters to reduce the background noise; the false positives were distinguished by introducing a blocked tyrosinase in the control group for comparison. To obtain the best blocker, the competitive experiments were performed using various known ligands. Using this strategy, three competitive inhibitors (protocatechuic acid; 3,5-di-O-caffeoylquinic acid; and 1,5-di-O-caffeoylquinic acid) and one mixed-type inhibitor (chlorogenic acid) were identified. These results were verified using tyrosinase inhibition assay, kinetic analysis, and structural simulation of the complex. Our experimental results suggest that the proposed strategy could be useful for high-throughput identification of tyrosinase specific inhibitors in natural products. Copyright © 2015 Elsevier B.V. All rights reserved.

Nano-structured silica coated mesoporous carbon micro-granules for potential application in water filtration

NASA Astrophysics Data System (ADS)

Das, Avik; Sen, D.; Mazumder, S.; Ghosh, A. K.

2017-05-01

A novel nano-composite spherical micro-granule has been synthesized using a facile technique of solvent evaporation induced assembly of nanoparticles for potential application in water filtration. The spherical micro-granule is comprised of nano-structured shell of hydrophilic silica encapsulating a hydrophobic mesoporous carbon at the core. Hierarchical structure of such core-shell micro-granules has been rigorously characterized using small-angle neutron and X-ray scattering techniques and complemented with scanning electron microscopy. The hydrophilic silica envelope around the carbon core helps in incorporation of such granules into the hydrophilic polymeric ultra-filtration membrane. The interstitial micro-pores present in the silica shell can serve as water transport channels and the mesoporus carbon core enhances the separation performance due its well adsorption characteristics. It has been found that the incorporation of such granules inside the ultra-filtration membrane indeed enhances the water permeability as well as the separation performance in a significant way.

Not-from-concentrate pilot plant 'Wonderful' cultivar pomegranate juice changes: Volatiles.

PubMed

Beaulieu, John C; Obando-Ulloa, Javier M

2017-08-15

Pilot plant ultrafiltration was used to mimic the dominant U.S. commercial pomegranate juice extraction method (hydraulic pressing whole fruit), to deliver a not-from-concentrate (NFC) juice that was high-temperature short-time pasteurized and stored at 4 and 25°C. Recovered were 46 compounds, of which 38 were routinely isolated and subjected to analysis of variance to assess these NFC juices. Herein, 18 of the 21 consensus pomegranate compounds were recovered. Ultrafiltration resulted in significant decreases for many compounds. Conversely, pasteurization resulted in compound increases. Highly significant decreases in 12 consensus compounds were observed during storage. Principal component analysis demonstrated clearly which compounds were tightly associated, and how storage samples behaved very similarly, independent of temperature. Based on these data and previous work we reported, this solid-phase microextraction (SPME) method delivered a robust 'Wonderful' volatile profile in NFC juices that is likely superior qualitatively and perhaps quantitatively to typical commercial offerings. Published by Elsevier Ltd.

Ultrafiltration by a compacted clay membrane-I. Oxygen and hydrogen isotopic fractionation

USGS Publications Warehouse

Coplen, T.B.; Hanshaw, B.B.

1973-01-01

Laboratory experiments were carried out to determine the magnitude of the isotopic fractionation of distilled water and of 0.01 N NaCl forced to flow at ambient temperature under a hydraulic pressure drop of 100 bars across a montmorillonite disc compacted to a porosity of 35 per cent by a pressure of 330 bars. The ultrafiltrates in both experiments were depleted in D by 2.5%. and in O18 by 0.8%. relative to the residual solution. No additional isotopic fractionation due to a salt filtering mechanism was observed at NaCl concentrations up to 0.01 N. Adsorption is most likely the principal mechanism which produces isotopic fractionation, but molecular diffusion may play a minor role. The results suggest that oxygen and hydrogen isotopic fractionation of ground water during passage through compacted clayey sediments should be a common occurrence, in accord with published interpretations of isotopic data from the Illinois and Alberta basins. ?? 1973.

Metabolic studies of an orally active platinum anticancer drug by liquid chromatography-electrospray ionization mass spectrometry.

PubMed

Poon, G K; Raynaud, F I; Mistry, P; Odell, D E; Kelland, L R; Harrap, K R; Barnard, C F; Murrer, B A

1995-09-29

Bis(acetato)amminedichloro(cyclohexylamine) platinum(IV) (JM216) is a new orally administered platinum complex with antitumor properties, and is currently undergoing phase II clinical trials. When JM216 was incubated with human plasma ultrafiltrate, 93% of the platinum species were protein-bound and 7% were unbound. The unbound platinum complexes in the ultrafiltrates of human plasma were analysed using a liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method. Apart from the parent drug, four metabolites were identified and characterised. These include JM118 [amminedichloro(cyclohexylamine) platinum(II)], JM383 [bis(acetato)ammine(cyclohexylamine)dihydroxo platinum(IV)] and the two isomers JM559 and JM518 [bis(acetato)amminechloro(cyclohexylamine) hydroxo platinum(IV)]. Their elemental compositions were determined by accurate mass measurement during the LC analysis, to confirm their identities. Quantitation of these metabolites by off-line LC atomic absorption spectroscopy demonstrated that JM118 is the major metabolite in plasma from patients receiving JM216 treatment.

Hydrophilicity and antifouling property of membrane materials from cellulose acetate/polyethersulfone in DMAc.

PubMed

Sun, Zhonghua; Chen, Fushan

2016-10-01

In this study, cellulose acetate (CA) was blended with polyethersulfone (PES) to endow the ultrafiltration membrane with the improved hydrophilicity and antifouling property by using N,N-dimethylacetamide (DMAc) as the solvent. The effects of blend composition and evaporation time on the mechanical strength and pure water flux were investigated. It was found that the optimal composition of the casting solution was: 18wt% (PES), 4wt% (Polyvinylpyrrolidone K30), 3wt% (CA) and 20s (Evaporation time). The characteristics of CA-PES blend membranes were investigated through the methods of contact angle goniometer, antifouling property, compatibility, thermo gravimetric analysis and SEM. The results showed that the hydrophilicity and antifouling property of CA-PES ultrafiltration membranes were enhanced in comparison with the pure PES membranes. The CA-PES membranes exhibited semi-compatibility and good thermal stability below 270°C. This study provided a potential industrial application prospect of CA-PES membranes prepared in DMAc. Copyright © 2016 Elsevier B.V. All rights reserved.

Ultrafiltration and endotoxin removal from dialysis fluids.

PubMed

Di Felice, A; Cappelli, G; Facchini, F; Tetta, C; Cornia, F; Aimo, G; Lusvarghi, E

1993-06-01

Biocompatibility in hemodialysis is now regarded as a multifactorial problem and dialysate represents a main risk. Pyrogenic fractions mostly coming from gram-negative bacteria easily pass through dialysis membrane, either by backdiffusion or by backfiltration, and induce blood cell activation. To demonstrate the long-term efficiency of a 2 m2 polyamide ultrafilter in producing a pyrogen free solution, we used an experimental circuit ultrafiltering for 240 hours (500 ml/min) a bicarbonate dialysate contaminated (5 to 48 EU/ml) by a Pseudomonas aeruginosa filtrate. The efficiency was monitored by LAL-test and IL-1 PBMC so to detect not only lipid A containing endotoxins but also other cytokines inducing bacterial fractions. At the post-ultrafilter sampling port the LAL-test was < 0.005 to 0.034 EU/ml; IL-1 PBMC was below the detection limit (20 pg/ml) being 27 to 63 pg/ml at the pre-ultrafilter level. Polyamide ultrafiltration represents an efficient system to obtain an endotoxin-free dialysate and a single filter works up to 240 hours.

Successive membrane separation processes simplify concentration of lipases produced by Aspergillus niger by solid-state fermentation.

PubMed

Reinehr, Christian Oliveira; Treichel, Helen; Tres, Marcus Vinicius; Steffens, Juliana; Brião, Vandré Barbosa; Colla, Luciane Maria

2017-06-01

In this study, we developed a simplified method for producing, separating, and concentrating lipases derived from solid-state fermentation of agro-industrial residues by filamentous fungi. First, we used Aspergillus niger to produce lipases with hydrolytic activity. We analyzed the separation and concentration of enzymes using membrane separation processes. The sequential use of microfiltration and ultrafiltration processes made it possible to obtain concentrates with enzymatic activities much higher than those in the initial extract. The permeate flux was higher than 60 L/m 2 h during microfiltration using 20- and 0.45-µm membranes and during ultrafiltration using 100- and 50-kDa membranes, where fouling was reversible during the filtration steps, thereby indicating that the fouling may be removed by cleaning processes. These results demonstrate the feasibility of lipase production using A. niger by solid-state fermentation of agro-industrial residues, followed by successive tangential filtration with membranes, which simplify the separation and concentration steps that are typically required in downstream processes.

Treatment of a waste oil-in-water emulsion from a copper-rolling process by ultrafiltration and vacuum evaporation.

PubMed

Gutiérrez, Gemma; Lobo, Alberto; Benito, José M; Coca, José; Pazos, Carmen

2011-01-30

A process is proposed for the treatment of a waste oil-in-water (O/W) emulsion generated in an industrial copper-rolling operation. The use of demulsifier agents improves the subsequent treatment by techniques such as ultrafiltration (UF) or evaporation. The effluent COD is reduced up to 50% when the O/W emulsion is treated by UF using a flat 30 nm TiO(2) ceramic membrane (ΔP = 0.1 MPa) and up to 70% when it is treated by vacuum evaporation, after an emulsion destabilization pretreatment in both cases. Increases in the UF permeate flux and in the evaporation rate are observed when a chemical demulsifier is used in the pretreatment step. A combined process consisting of destabilization/settling, UF, and vacuum evaporation can yield a very high-quality aqueous effluent that could be used for process cooling or emulsion reformulation. Copyright © 2010 Elsevier B.V. All rights reserved.

Rennet-induced gelation of concentrated milk in the presence of sodium caseinate: differences between milk concentration using ultrafiltration and osmotic stressing.

PubMed

Krishnankutty Nair, P; Corredig, M

2015-01-01

Concentrating milk is a common unit operation in the dairy industry. With the reduction of water, the particles interact more frequently with each other and the functionality of the casein micelles may depend on the interactions occurring during concentration. The objective of this research was to investigate the effect of concentration on the renneting properties of the casein micelles by comparing 2 concentration methods: ultrafiltration and osmotic stressing. Both methods selectively concentrate the protein fraction of milk, while the composition of the soluble phase is unaltered. To evaluate possible differences in the rearrangements of the casein micelles during concentration, renneting properties were evaluated with or without the addition of soluble caseins, added either before or after concentration. The results indicate that casein micelles undergo rearrangements during concentration and that shear during membrane filtration may play a role in affecting the final properties of the milk. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Surface Properties and Permeability of Poly(Vinylidene Fluoride)-Clays (PVDF/Clays) Composite Membranes

NASA Astrophysics Data System (ADS)

Pramono, E.; Ahdiat, M.; Simamora, A.; Pratiwi, W.; Radiman, C. L.; Wahyuningrum, D.

2017-07-01

Surface properties are important factors that determine the performance of ultrafiltration membranes. This study aimed to investigate the effects of clay addition on the surface properties and membrane permeability of PVDF (poly-vinylidene fluoride) membranes. Three types of clay with different particle size were used in this study, namely montmorillonite-MMT, bentonite-BNT and cloisite 15A-CLS. The PVDF-clay composite membranes were prepared by phase inversion method using PEG as additive. The hydrophobicity of membrane surface was characterized by contact angle. The membrane permeability was determined by dead- end ultrafiltration with a trans-membrane pressure of 2 bars. In contact angle measurement, water contact angle of composite membranes is higher than PVDF membrane. The addition of clays decreased water flux but increased of Dextran rejection. The PVDF-BNT composite membranes reach highest Dextran rejection value of about 93%. The type and particle size of clay affected the hydrophobicity of membrane surface and determined the resulting membrane structure as well as the membrane performance.

Ultrafiltration for acute decompensated heart failure: cost, reimbursement, and financial impact.

PubMed

Ross, Edward A; Bellamy, Frank B; Hawig, Scott; Kazory, Amir

2011-05-01

In addition to the proposed pathophysiologic mechanisms whereby ultrafiltration (UF) can be advantageous over diuretics in the treatment of heart failure, there can also be financial and resource-utilization reasons for pursuing this extracorporeal strategy. In those cases in which the clinical outcomes would be equivalent, however, the decision whether to pursue UF will depend greatly on the anticipated hospitalization length of stay (LOS), the patient population's pay or mix, the needs and costs for high-acuity (eg, intensive care unit) care, and widely varying expenses for the equipment and disposable supplies. From a fiscal perspective, the financial viability of UF programs revolves around how improvements in LOS, resource utilization, and readmissions relate to the typical diagnosis-driven (eg, diagnosis-related group) reimbursement. We analyzed the impact of these various factors so as to better understand how the intensity (and expense) of pharmaceutical and extracorporeal therapies impacts a single admission, as well as to serve as the basis for developing strategies for optimizing long-term care. 2011 Wiley Periodicals, Inc.

Slow slip events and seismic tremor at circum-Pacific subduction zones

NASA Astrophysics Data System (ADS)

Schwartz, Susan Y.; Rokosky, Juliana M.

2007-09-01

It has been known for a long time that slip accompanying earthquakes accounts for only a fraction of plate tectonic displacements. However, only recently has a fuller spectrum of strain release processes, including normal, slow, and silent earthquakes (or slow slip events) and continuous and episodic slip, been observed and generated by numerical simulations of the earthquake cycle. Despite a profusion of observations and modeling studies the physical mechanism of slow slip events remains elusive. The concurrence of seismic tremor with slow slip episodes in Cascadia and southwestern Japan provides insight into the process of slow slip. A perceived similarity between subduction zone and volcanic tremor has led to suggestions that slow slip involves fluid migration on or near the plate interface. Alternatively, evidence is accumulating to support the notion that tremor results from shear failure during slow slip. Global observations of the location, spatial extent, magnitude, duration, slip rate, and periodicity of these aseismic slip transients indicate significant variation that may be exploited to better understand their generation. Most slow slip events occur just downdip of the seismogenic zone, consistent with rate- and state-dependent frictional modeling that requires unstable to stable transitional properties for slow slip generation. At a few convergent margins the occurrence of slow slip events within the seismogenic zone makes it highly likely that transitions in frictional properties exist there and are the loci of slow slip nucleation. Slow slip events perturb the surrounding stress field and may either increase or relieve stress on a fault, bringing it closer to or farther from earthquake failure, respectively. This paper presents a review of slow slip events and related seismic tremor observed at plate boundaries worldwide, with a focus on circum-Pacific subduction zones. Trends in global observations of slow slip events suggest that (1) slow slip is a common phenomena observed at almost all subduction zones with instrumentation capable of recording it, (2) different frictional properties likely control fast versus slow slip, (3) the depth range of slow slip may be related to the thermal properties of the plate interface, and (4) the equivalent seismic moment of slow slip events is proportional to their duration (Moατ), different from the Moατ3 scaling observed for earthquakes.

Nasal continuous positive airway pressure: does bubbling improve gas exchange?

PubMed

Morley, C J; Lau, R; De Paoli, A; Davis, P G

2005-07-01

In a randomised crossover trial, 26 babies, treated with Hudson prong continuous positive airway pressure (CPAP) from a bubbling bottle, received vigorous, high amplitude, or slow bubbling for 30 minutes. Pulse oximetry, transcutaneous carbon dioxide, and respiratory rate were recorded. The bubbling rates had no effect on carbon dioxide, oxygenation, or respiratory rate.

Eflornithine

MedlinePlus

... than prescribed by your doctor.Eflornithine cream slows hair growth but does not prevent it. You should continue to use your current method of hair removal (e.g., shaving, plucking, cutting) or treatment ...

The Slow Control System of the Auger Fluorescence Detectors

NASA Astrophysics Data System (ADS)

Barenthien, N.; Bethge, C.; Daumiller, K.; Gemmeke, H.; Kampert, K.-H.; Wiebusch, C.

2003-07-01

The fluorescence detector (FD) of the Pierre Auger experiment [1] comprises 24 telescopes that will be situated in 4 remote buildings in the Pampa Amarilla. It is planned to run the fluorescence detectors in absence of operators on site. Therefore, the main task of the Slow Control System (SCS) is to ensure a secure remote operation of the FD system. The Slow Control System works autonomously and continuously monitors those parameters which may disturb a secure operation. Commands from the data-acquisition system or the remote operator are accepted only if they do not violate safety rules that depend on the actual experimental conditions (e.g. high-voltage, wind-sp eed, light, etc.). In case of malfunctions (power failure, communication breakdown, ...) the SCS performs an orderly shutdown and subsequent startup of the fluorescence detector system. The concept and the implementation of the Slow Control System are presented.

Tough Choices or Tough Times: The Report of the "New" Commission on the Skills of the American Workforce. Executive Summary

ERIC Educational Resources Information Center

National Center on Education and the Economy (NJ1), 2007

2007-01-01

A swiftly rising number of American workers at every skill level are in direct competition with workers in every corner of the globe. While the United States' relative position in the world's education league tables has continued its long slow decline, the structure of the global economy has continued to evolve. If the U.S. continue on its current…

Monitoring Cole-Cole parameters during haemodialysis (HD).

PubMed

Al-Surkhi, Omar I; Riu, P J; Vazquez, F F; Ibeas, J

2007-01-01

The investigation of the hydration process during the haemodialysis treatment sessions is very important for the development of methods for predicting the unbalanced fluid shifts and hypotension crisis hence improving the quality of the haemodialysis procedure. Bioimpedance measurements can give valuable information about the tissue under measurement, therefore characterizing the tissue. In this work we propose a non-invasive method based on local multifrequency bioimpedance measurements that allow us to determine the fluid distribution and variations during haemodialysis. Clinical measurements were done using 10 HD patients during 60 HD sessions. Bioimpedance data, ultrafiltration volume, blood volume and blood heamatocrit variations were recorded continuously during the HD sessions. Bioimpedance of the local tissue was measured with a 4-elctrode impedance system using surface electrodes with sampling rate of 1meas./4min. at 6 different frequencies. The measured impedances were fitted into Cole-Cole model and the Cole-Cole parameters were continuously determined for each measurement point during the HD session. The 4 Cole-Cole parameters (R 00, R 0, Fc,alpha) and their variations were evaluated. Impedance values at infinite and zero (R 00, R 0) frequencies were extrapolated from Cole-Cole mathematical model. These values are assumed to represent the impedance of total tissue fluid and the impedance of the extracellular space respectively.

The Effects of Sleep Continuity Disruption on Positive Mood and Sleep Architecture in Healthy Adults.

PubMed

Finan, Patrick H; Quartana, Phillip J; Smith, Michael T

2015-11-01

The purpose of this study was to test an experimental model of the effects of sleep continuity disturbance on sleep architecture and positive mood in order to better understand the mechanisms linking insomnia and depression. Participants were randomized to receive 3 consecutive nights of sleep continuity disruption via forced nocturnal awakenings (FA, n = 21), or one of two control conditions: restricted sleep opportunity (RSO, n = 17) or uninterrupted sleep (US, n = 24). The study was set in an inpatient clinical research suite. Healthy, good-sleeping men and women were included. Polysomnography was used to measure sleep architecture, and mood was assessed via self-report each day. Compared to restricted sleep opportunity controls, forced awakenings subjects had significantly less slow wave sleep (P < 0.05) after the first night of sleep deprivation, and significantly lower positive mood (P < 0.05) after the second night of sleep deprivation. The differential change in slow wave sleep statistically mediated the observed group differences in positive mood (P = 0.002). To our knowledge, this is the first human experimental study to demonstrate that, despite comparable reductions in total sleep time, partial sleep loss from sleep continuity disruption is more detrimental to positive mood than partial sleep loss from delaying bedtime, even when controlling for concomitant increases in negative mood. With these findings, we provide temporal evidence in support of a putative biologic mechanism (slow wave sleep deficit) that could help explain the strong comorbidity between insomnia and depression. © 2015 Associated Professional Sleep Societies, LLC.

A Reverse Osmosis System for an Advanced Separation Process Laboratory.

ERIC Educational Resources Information Center

Slater, C. S.; Paccione, J. D.

1987-01-01

Focuses on the development of a pilot unit for use in an advanced separations process laboratory in an effort to develop experiments on such processes as reverse osmosis, ultrafiltration, adsorption, and chromatography. Discusses reverse osmosis principles, the experimental system design, and some experimental studies. (TW)

LC-MS/MS and UPLC-UV evaluation of anthocyanins and anthocyanidins during rabbiteye blueberry juice processing

USDA-ARS?s Scientific Manuscript database

Blueberry juice processing includes multiple steps and each affect the chemical composition of the berries, including thermal degradation of anthocyanins. Not from concentrate juice was made by heating and enzyme processing blueberries before pressing followed by ultrafiltration and pasteurization. ...

USE OF MEMBRANE BIOREACTOR FOR BIODEGRADATION OF MTBE IN CONTAMINATED WATER1

EPA Science Inventory

An ultrafiltration membrane bioreactor was evaluated for biodegradation of methyl tert-butyl ether (MTBE) in contaminated water. The system was fed 5 mg/L MTBE in granular activated carbon (GAC) treated Cincinnati tap water containing ample buffer and nutrients. Within 120...

Earthquake cycle deformation in Mexico and Central America constrained by GPS: Implications for coseismic, postseismic, and slow slip

NASA Astrophysics Data System (ADS)

Graham, Shannon E.

Using surface deformation measured by GPS stations within Mexico and Central America, I model coseismic slip, Coulomb stress changes, postseismic afterslip, and slow slip events in order to increase our knowledge of the earthquake deformation cycle in seismically hazardous regions. In Chapter 1, I use GPS data to estimate coseismic slip due to the May 28, 2009 Swan Islands fault earthquake off the coast of Honduras and then use the slip distribution to calculate Coulomb stress changes for the earthquake. Coulomb stress change calculations resolve stress transfer to the seismically hazardous Motagua fault and further show an unclamping of normal faults in northern Honduras. In Chapter 2, the focus shifts to southern Mexico, where continuous GPS measurements since the mid-1990s are revolutionizing our understanding of the flatly subducting Cocos plate. I perform a time-dependent inversion of continuous GPS observations of the 2011-2012 slow slip event (SSE) to estimate the location and magnitude of slow slip preceding the March 20, 2012 Ometepec earthquake. Coulomb stress changes as a result of slip during the SSE are consistent with the hypothesis that the SSE triggered the Ometepec earthquake. Chapter 3 describes inversions for slip both during and after the Ometepec earthquake. Time-dependent modeling of the first six months of postseismic deformation reveals that fault afterslip extended ˜250 km inland to depths of ˜50 km along the Cocos plate subduction. The postseismic afterslip and previous SSEs in southern Mexico occur at similar depths down-dip from the seismogenic zone, indicating that transitional areas of the subduction interface underlie much of southern Mexico. Finally, I perform the first time-dependent modeling of SSEs below Mexico and the first to exploit all available continuous GPS stations in southern and central Mexico. The results provide a more complete and consistent catalog of modeled SSE for the Mexico subduction zone (MSZ) than is currently available and add to our understanding of how SSEs on the subduction interface evolve in time, migrate in space, and possibly interact. I find that slow slip along the MSZ migrates across the gap between the Guerrero and Oaxaca regions, contrary to previous results.

Receptivity of Hypersonic Boundary Layers to Distributed Roughness and Acoustic Disturbances

NASA Technical Reports Server (NTRS)

Balakumar, P.

2013-01-01

Boundary-layer receptivity and stability of Mach 6 flows over smooth and rough seven-degree half-angle sharp-tipped cones are numerically investigated. The receptivity of the boundary layer to slow acoustic disturbances, fast acoustic disturbances, and vortical disturbances is considered. The effects of three-dimensional isolated roughness on the receptivity and stability are also simulated. The results for the smooth cone show that the instability waves are generated in the leading edge region and that the boundary layer is much more receptive to slow acoustic waves than to the fast acoustic waves. Vortical disturbances also generate unstable second modes, however the receptivity coefficients are smaller than that of the slow acoustic wave. Distributed roughness elements located near the nose region decreased the receptivity of the second mode generated by the slow acoustic wave by a small amount. Roughness elements distributed across the continuous spectrum increased the receptivity of the second mode generated by the slow and fast acoustic waves and the vorticity wave. The largest increase occurred for the vorticity wave. Roughness elements distributed across the synchronization point did not change the receptivity of the second modes generated by the acoustic waves. The receptivity of the second mode generated by the vorticity wave increased in this case, but the increase is lower than that occurred with the roughness elements located across the continuous spectrum. The simulations with an isolated roughness element showed that the second mode waves generated by the acoustic disturbances are not influenced by the small roughness element. Due to the interaction, a three-dimensional wave is generated. However, the amplitude is orders of magnitude smaller than the two-dimensional wave.

On generic obstructions to recovering correct statistics from climate simulations: Homogenization for deterministic maps and multiplicative noise

NASA Astrophysics Data System (ADS)

Gottwald, Georg; Melbourne, Ian

2013-04-01

Whereas diffusion limits of stochastic multi-scale systems have a long and successful history, the case of constructing stochastic parametrizations of chaotic deterministic systems has been much less studied. We present rigorous results of convergence of a chaotic slow-fast system to a stochastic differential equation with multiplicative noise. Furthermore we present rigorous results for chaotic slow-fast maps, occurring as numerical discretizations of continuous time systems. This raises the issue of how to interpret certain stochastic integrals; surprisingly the resulting integrals of the stochastic limit system are generically neither of Stratonovich nor of Ito type in the case of maps. It is shown that the limit system of a numerical discretisation is different to the associated continuous time system. This has important consequences when interpreting the statistics of long time simulations of multi-scale systems - they may be very different to the one of the original continuous time system which we set out to study.

The Role of Adaptive Photorefractive Power Limiting on Acousto-Optic Radio Frequency (RF) Signal Excision

DTIC Science & Technology

2001-12-01

using TeO2 , A-O cell, slow acoustic wave). Beam deflection is a continuous function of the input voltage power spectrum; however, the spot width...than for isotropic crystals. Thus, anisotropic, A-O materials, such as TeO2 , have advantages for high RF bandwidth; slow acoustic speeds give better...112 Unfortunately, signal resolution worsened because the new TeO2 crystal was designed to operate in the longitudinal acoustic mode, ua = 5.5 Km

The Strategic Context for Assessing Long Range Offense and Active Defense.

DTIC Science & Technology

1986-10-27

such Europeans do not really think that there is much of a Soviet nuclear threat to Western Europe, but d. hink that there is an American threat--or at...American military innovation has slowed down. It has been clear for many years that continuing references to a quantitative strategic arms race...have for a long time called for renewed efforts to " slow down the rate of weapons innovation" and "hence to reduce the frequency of introduction of

PROBING REACTIVITY OF DISSOLVED ORGANIC MATTER FOR DISINFECTION BY-PRODUCT FORMATION USING XAD-8 RESIN ADSORPTION AND ULTRAFILTRATION FRACTIONATION. (R828045)

EPA Science Inventory

The disinfection by-product (DBP) reactivity (yield and speciation upon reaction with chlorine) of dissolved organic matter (DOM) isolated from two surface waters was investigated. The source waters, each having significantly different specific ultraviolet absorbance (SUVA

Ultrafiltration of Protein Solutions: A Laboratory Experiment

ERIC Educational Resources Information Center

Pansare, Vikram J.; Tien, Daniel; Prud'homme, Robert K.

2015-01-01

Biology is playing an increasingly important role in the chemical engineering curriculum. We describe a set of experiments we have implemented in our Undergraduate Laboratory course giving students practical insights into membrane separation processes for protein processing. The goal of the lab is to optimize the purification and concentration of…

The Use of Cognitive Strategies To Enhance Motor Skill Acquisition and Retention in the Elderly.

ERIC Educational Resources Information Center

Anshel, Mark H.

It has been hypothesized that the use of techniques to enhance motor skill acquisition and retention in the elderly may retard the onset of retirement, result in the continuation of a productive professional career, allow continued participation in recreational activities, and possibly slow the decline in physiological functions that normally…

EFRT M12 Issue Resolution: Comparison of PEP and Bench-Scale Oxidative Leaching Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rapko, Brian M.; Brown, Christopher F.; Eslinger, Paul W.

2009-08-14

Pacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). The Pretreatment Engineering Platform (PEP) was designed and constructed and is to be operated as part of a plan to respond to issue M12, “Undemonstrated Leaching Processes.” The PEP is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, and slurry washing processes. The PEP replicates the WTP leaching processesmore » using prototypic equipment and control strategies. The PEP also includes non-prototypic ancillary equipment to support the core processing. Two operating scenarios are currently being evaluated for the ultrafiltration process (UFP) and leaching operations. The first scenario has caustic leaching performed in the UFP-2 ultrafiltration feed vessels (i.e., vessel UFP-VSL-T02A in the PEP; and vessels UFP-VSL-00002A and B in the WTP PTF). The second scenario has caustic leaching conducted in the UFP-1 ultrafiltration feed preparation vessels (i.e., vessels UFP-VSL-T01A and B in the PEP; vessels UFP-VSL-00001A and B in the WTP PTF). In both scenarios, 19-M sodium hydroxide solution (NaOH, caustic) is added to the waste slurry in the vessels to dissolve solid aluminum compounds (e.g., gibbsite, boehmite). Caustic addition is followed by a heating step that uses direct steam injection to accelerate the leaching process. Following the caustic leach, the vessel contents are cooled using vessel cooling jackets and/or external heat exchangers. The main difference between the two scenarios is that for leaching in UFP1, the 19-M NaOH is added to un-concentrated waste slurry (3 to 8 wt% solids), while for leaching in UFP2, the slurry is concentrated to nominally 20 wt% solids using cross-flow ultrafiltration before the addition of caustic. For wastes that have significantly high chromium content, the caustic leaching and slurry dewatering is followed by adding sodium permanganate to UFP-VSL-T02A, and the slurry is subjected to oxidative leaching at nominally ambient temperature. The purpose of the oxidative leaching is to selectively oxidize the poorly alkaline-soluble Cr(III) believed to be the insoluble form in Hanford tank sludge to the much more alkaline-soluble Cr(VI), e.g., chromate. The work described in this report provides the test results that are related to the efficiency of the oxidative leaching process to support process modeling based on tests performed with a Hanford waste simulant. The tests were completed both at the lab-bench scale and in the PEP. The purpose of this report is to summarize the results from both scales that are related to oxidative leaching chemistry to support a scale factor for the submodels to be used in the G2 model, which predicts WTP operating performance. Owing to schedule constraints, the PEP test data to be included in this report are limited to those from Integrated Tests A (T01 A/B caustic leaching) and B (T02A caustic leaching).« less

Seismicity rate increases associated with slow slip episodes prior to the 2012 Mw 7.4 Ometepec earthquake

NASA Astrophysics Data System (ADS)

Colella, Harmony V.; Sit, Stefany M.; Brudzinski, Michael R.; Graham, Shannon E.; DeMets, Charles; Holtkamp, Stephen G.; Skoumal, Robert J.; Ghouse, Noorulann; Cabral-Cano, Enrique; Kostoglodov, Vladimir; Arciniega-Ceballos, Alejandra

2017-04-01

The March 20, 2012 Mw 7.4 Ometepec earthquake in the Oaxaca region of Southern Mexico provides a unique opportunity to examine whether subtle changes in seismicity, tectonic tremor, or slow slip can be observed prior to a large earthquake that may illuminate changes in stress or background slip rate. Continuous Global Positioning System (cGPS) data reveal a 5-month-long slow slip event (SSE) between ∼20 and 35 km depth that migrated toward and reached the vicinity of the mainshock a few weeks prior to the earthquake. Seismicity in Oaxaca is examined using single station tectonic tremor detection and multi-station waveform template matching of earthquake families. An increase in seismic activity, detected with template matching using aftershock waveforms, is only observed in the weeks prior to the mainshock in the region between the SSE and mainshock. In contrast, a SSE ∼15 months earlier occurred at ∼25-40 km depth and was primarily associated with an increase in tectonic tremor. Together, these observations indicate that in the Oaxaca region of Mexico shallower slow slip promotes elevated seismicity rates, and deeper slow slip promotes tectonic tremor. Results from this study add to a growing number of published accounts that indicate slow slip may be a common pre-earthquake signature.

An integrated perspective of the continuum between earthquakes and slow-slip phenomena

USGS Publications Warehouse

Peng, Zhigang; Gomberg, Joan

2010-01-01

The discovery of slow-slip phenomena has revolutionized our understanding of how faults accommodate relative plate motions. Faults were previously thought to relieve stress either through continuous aseismic sliding, or as earthquakes resulting from instantaneous failure of locked faults. In contrast, slow-slip events proceed so slowly that slip is limited and only low-frequency (or no) seismic waves radiate. We find that slow-slip phenomena are not unique to the depths (tens of kilometres) of subduction zone plate interfaces. They occur on faults in many settings, at numerous scales and owing to various loading processes, including landslides and glaciers. Taken together, the observations indicate that slowly slipping fault surfaces relax most of the accrued stresses through aseismic slip. Aseismic motion can trigger more rapid slip elsewhere on the fault that is sufficiently fast to generate seismic waves. The resulting radiation has characteristics ranging from those indicative of slow but seismic slip, to those typical of earthquakes. The mode of seismic slip depends on the inherent characteristics of the fault, such as the frictional properties. Slow-slip events have previously been classified as a distinct mode of fault slip compared with that seen in earthquakes. We conclude that instead, slip modes span a continuum and are of common occurrence.

Rivastigmine Transdermal Patch

MedlinePlus

... also used to treat dementia in people with Parkinson's disease (a brain system disease with symptoms of slowing ... cure Alzheimer's disease or dementia in people with Parkinson's disease. Continue to use transdermal rivastigmine even if you ...

Accurate hybrid stochastic simulation of a system of coupled chemical or biochemical reactions.

PubMed

Salis, Howard; Kaznessis, Yiannis

2005-02-01

The dynamical solution of a well-mixed, nonlinear stochastic chemical kinetic system, described by the Master equation, may be exactly computed using the stochastic simulation algorithm. However, because the computational cost scales with the number of reaction occurrences, systems with one or more "fast" reactions become costly to simulate. This paper describes a hybrid stochastic method that partitions the system into subsets of fast and slow reactions, approximates the fast reactions as a continuous Markov process, using a chemical Langevin equation, and accurately describes the slow dynamics using the integral form of the "Next Reaction" variant of the stochastic simulation algorithm. The key innovation of this method is its mechanism of efficiently monitoring the occurrences of slow, discrete events while simultaneously simulating the dynamics of a continuous, stochastic or deterministic process. In addition, by introducing an approximation in which multiple slow reactions may occur within a time step of the numerical integration of the chemical Langevin equation, the hybrid stochastic method performs much faster with only a marginal decrease in accuracy. Multiple examples, including a biological pulse generator and a large-scale system benchmark, are simulated using the exact and proposed hybrid methods as well as, for comparison, a previous hybrid stochastic method. Probability distributions of the solutions are compared and the weak errors of the first two moments are computed. In general, these hybrid methods may be applied to the simulation of the dynamics of a system described by stochastic differential, ordinary differential, and Master equations.

Alfvén wave dynamics at the neighborhood of a 2.5D magnetic null-point

NASA Astrophysics Data System (ADS)

Sabri, S.; Vasheghani Farahani, S.; Ebadi, H.; Hosseinpour, M.; Fazel, Z.

2018-05-01

The aim of the present study is to highlight the energy transfer via the interaction of magnetohydrodynamic waves with a 2.5D magnetic null-point in a finite plasma-β regime of the solar corona. An initially symmetric Alfvén pulse at a specific distance from a magnetic null-point is kicked towards the isothermal null-point. A shock-capturing Godunov-type PLUTO code is used to solve the ideal magnetohydrodynamic set equations in the context of wave-plasma energy transfer. As the Alfvén wave propagates towards the magnetic null-point it experiences speed lowering which ends up in releasing energy along the separatrices. In this line owing to the Alfvén wave, a series of events take place that contribute towards coronal heating. Nonlinear induced waves are by products of the torsional Alfvén interaction with magnetic null-points. The energy of these induced waves which are fast magnetoacoustic (transverse) and slow magnetoacoustic (longitudinal) waves are supplied by the Alfvén wave. The nonlinearly induced density perturbations are proportional to the Alfvén wave energy loss. This supplies energy for the propagation of fast and slow magnetoacoustic waves, where in contrast to the fast wave the slow wave experiences a continuous energy increase. As such, the slow wave may transfer its energy to the medium at later times, maintaining a continuous heating mechanism at the neighborhood of a magnetic null-point.

Pharmacokinetics of Cefepime during Continuous Renal Replacement Therapy in Critically Ill Patients

PubMed Central

Malone, Rebecca S.; Fish, Douglas N.; Abraham, Edward; Teitelbaum, Isaac

2001-01-01

The pharmacokinetics of cefepime were studied in 12 adult patients in intensive care units during continuous venovenous hemofiltration (CVVH) or continuous venovenous hemodiafiltration (CVVHDF) with a Multiflow60 AN69HF 0.60-m2 polyacrylonitrile hollow-fiber membrane (Hospal Industrie, Meyzieu, France). Patients (mean age, 52.0 ± 13.0 years [standard deviation]; mean weight, 96.7 ± 18.4 kg) received 1 or 2 g of cefepime every 12 or 24 h (total daily doses of 1 to 4 g/day) by intravenous infusion over 15 to 30 min. Pre- and postmembrane blood (serum) samples and corresponding ultrafiltrate or dialysate samples were collected 1, 2, 4, 8, and 12 or 24 h (depending on dosing interval) after completion of the drug infusion. Drug concentrations were measured using validated high-performance liquid chromatography methods. Mean systemic clearance (CLS) and elimination half-life (t1/2) of cefepime were 35.9 ± 6.0 ml/min and 12.9 ± 2.6 h during CVVH versus 46.8 ± 12.4 ml/min and 8.6 ± 1.4 h during CVVHDF, respectively. Cefepime clearance was substantially increased during both CVVH and CVVHDF, with membrane clearance representing 40 and 59% of CLS, respectively. The results of this study confirm that continuous renal replacement therapy contributes substantially to total CLS of cefepime and that CVVHDF appears to remove cefepime more efficiently than CVVH. Cefepime doses of 2 g/day (either 2 g once daily or 1 g twice daily) appear to achieve concentrations adequate to treat most common gram-negative pathogens (MIC ≤ 8 μg/ml) during CVVH or CVVHDF. PMID:11600370

Sodium Chloride and Water Transport in the Medullary Thick Ascending Limb of Henle. EVIDENCE FOR ACTIVE CHLORIDE TRANSPORT

PubMed Central

Rocha, Antonino S.; Kokko, Juha P.

1973-01-01

Transport of NaCl and water was examined in the rabbit medullary thick ascending limb of Henle (ALH) by perfusing isolated segments of these nephrons in vitro. Osmotic water permeability was evaluated by perfusing tubules against imposed osmotic gradients. In these experiments the net transport of fluid remained at zero when segments of thick ALH were perfused with isotonic ultrafiltrate in a bath of rabbit serum in which the serum osmolality was increased by the addition of either 239±8 mosmol/liter of raffinose or 232±17 mosmol of NaCl indicating that the thick ascending limb of Henle is impermeant to osmotic flow of water. When these tubules were perfused at slow rates with isosmolal ultrafiltrate of same rabbit serum as used for the bath, the effluent osmolality was consistently lowered to concentrations less than the perfusate and the bath. That this decrease in collected fluid osmolality represented salt transport was demonstrated in a separate set of experiments in which it was shown that the sodium and chloride concentrations decreased to 0.79±0.02 and 0.77±0.02 respectively when compared with the perfusion fluid concentrations. In each instance the simultaneously determined transtubular potential difference (PD) revealed the lumen to be positive with the magnitude dependent on the perfusion rate. At flow rates above 2 nl·min-1, the mean transtubular PD was stable and equal to 6.70±0.34 mv. At stop-flow conditions this PD became more positive. Ouabain and cooling reversibly decreased the magnitude of this PD. The transtubular PD remained positive, 3.3±0.2 mV, when complete substitution of Na by choline was carried out in both the perfusion fluid and the bathing media. These results are interpreted to indicate that the active transport process is primarily an electrogenic chloride mechanism. The isotopic permeability coefficient for Na was 6.27±0.38 × 10-5 cm·s-1 indicating that the thick ALH is approximately as permeable to Na as the proximal convoluted tubule. The chloride permeability coefficient for the thick ALH was 1.06±0.12 × 10-5 cm·s-1 which is significantly less than the chloride permeability of the proximal tubule. These data demonstrate that the medullary thick ascending limb of Henle is water impermeable while having the capacity for active outward solute transport as a consequence of an electrogenic chloride pump. The combination of these characteristics allows this segment to generate a dilute tubular fluid and participate as the principal energy source for the overall operation of the countercurrent multiplication system. Images PMID:4685086

Event-related potentials for post-error and post-conflict slowing.

PubMed

Chang, Andrew; Chen, Chien-Chung; Li, Hsin-Hung; Li, Chiang-Shan R

2014-01-01

In a reaction time task, people typically slow down following an error or conflict, each called post-error slowing (PES) and post-conflict slowing (PCS). Despite many studies of the cognitive mechanisms, the neural responses of PES and PCS continue to be debated. In this study, we combined high-density array EEG and a stop-signal task to examine event-related potentials of PES and PCS in sixteen young adult participants. The results showed that the amplitude of N2 is greater during PES but not PCS. In contrast, the peak latency of N2 is longer for PCS but not PES. Furthermore, error-positivity (Pe) but not error-related negativity (ERN) was greater in the stop error trials preceding PES than non-PES trials, suggesting that PES is related to participants' awareness of the error. Together, these findings extend earlier work of cognitive control by specifying the neural correlates of PES and PCS in the stop signal task.

Reconsidering earthquake scaling

USGS Publications Warehouse

Gomberg, Joan S.; Wech, Aaron G.; Creager, Kenneth; Obara, K.; Agnew, Duncan

2016-01-01

The relationship (scaling) between scalar moment, M0, and duration, T, potentially provides key constraints on the physics governing fault slip. The prevailing interpretation of M0-T observations proposes different scaling for fast (earthquakes) and slow (mostly aseismic) slip populations and thus fundamentally different driving mechanisms. We show that a single model of slip events within bounded slip zones may explain nearly all fast and slow slip M0-T observations, and both slip populations have a change in scaling, where the slip area growth changes from 2-D when too small to sense the boundaries to 1-D when large enough to be bounded. We present new fast and slow slip M0-T observations that sample the change in scaling in each population, which are consistent with our interpretation. We suggest that a continuous but bimodal distribution of slip modes exists and M0-T observations alone may not imply a fundamental difference between fast and slow slip.

Assessment of a Point-of-Use Ultrafiltration System for Turbidity and Microbial Pathogen Removal

EPA Science Inventory

U.S. EPA’s Office of Research and Development has been evaluating the performance of point-of-use (POU) devices designed for use in homes and small businesses for many years. In collaboration with the University of Cincinnati, a series of pilot-scale tests were conducted on a Mat...

Effects of Bloom-Forming Algae on Fouling of Integrated Membrane Systems in Seawater Desalination

ERIC Educational Resources Information Center

Ladner, David Allen

2009-01-01

Combining low- and high-pressure membranes into an integrated membrane system is an effective treatment strategy for seawater desalination. Low-pressure microfiltration (MF) and ultrafiltration (UF) membranes remove particulate material, colloids, and high-molecular-weight organics leaving a relatively foulant-free salt solution for treatment by…

Not-from-concentrate pilot plant ‘Wonderful’ cultivar pomegranate juice changes: Volatiles

USDA-ARS?s Scientific Manuscript database

Pilot plant ultrafiltration was used to mimic the dominant U.S. commercial pomegranate juice extraction method (hydraulic pressing whole fruit), to deliver a not-from-concentrate (NFC) juice that was high-temperature short-time pasteurized and stored at 4 and 25 °C. Recovered were 46 compounds, of ...

Rapid purification of fluorescent enzymes by ultrafiltration

NASA Technical Reports Server (NTRS)

Benjaminson, M. A.; Satyanarayana, T.

1983-01-01

In order to expedite the preparation of fluorescently tagged enzymes for histo-cyctochemistry, a previously developed method employing gel column purification was compared with a more rapid modern technique using the Millipore Immersible CX-ultrafilter. Microscopic evaluation of the resulting conjugates showed comparable products. Much time and effort is saved using the new technique.

Rapid purification of fluorescent enzymes by ultrafiltration

NASA Technical Reports Server (NTRS)

Benjaminson, M. A.; Satyanarayana, T.

1983-01-01

In order to expedite the preparation of fluorescently tagged enzymes for histo/cytochemistry, a previously developed method employing gel column purification was compared with a more rapid modern technique using the Millipore Immersible CX-ultrafilter. Microscopic evaluation of the resulting conjugates showed comparable products. Much time and effort is saved using the new technique.

Purification of Pseudomonas aeruginosa Endotoxin by Membrane Partition Chromatography

PubMed Central

Rubio, Nazario; Lopez, Rubens

1972-01-01

A procedure is described for obtaining large quantities of purified endotoxin of Pseudomonas aeruginosa by using Diaflo ultrafiltration. This method allowed us to isolate from the protein-lipopolysaccharide complex two low-molecular-weight substances which do not play any antigenic role. It provides a useful tool for immunological purposes. Images PMID:4622818

Effect of filtration rates on hollow fiber ultrafilter concentration of viruses and protozoans from large volumes of water

EPA Science Inventory

Aims: To describe the ability of tangential flow hollow-fiber ultrafiltration to recover viruses from large volumes of water when run either at high filtration rates or lower filtration rates and recover Cryptosporidium parvum at high filtration rates. Methods and Results: Wate...

Ultrafiltration Membrane Module Virus Reduction at Different Fluxes, and with a Cut Fiber

EPA Science Inventory

NSF International evaluated The Dow Chemical Company SFD-2880 UF membrane module for MS2 reduction at four different fluxes, and also with and without a cut fiber, to compare MS2 log reduction under the different scenarios. All tests were conducted in accordance with the U.S. En...

Assessment of a Point-of-Use Ultrafiltration System for Turbidity and Microbial Pathogen Removal

EPA Science Inventory

U.S. EPA’s Office of Research and Development has been evaluating the performance of point-of-use (POU) devices designed for use in homes and small businesses for many years. In collaboration with the University of Cincinnati, a series of pilot-scale tests were conducted on a Ma...

Preparation of Cu2O nanowire-blended polysulfone ultrafiltration membrane with improved stability and antimicrobial activity

NASA Astrophysics Data System (ADS)

Xu, Zehai; Ye, Shuaiju; Fan, Zheng; Ren, Fanghua; Gao, Congjie; Li, Qingbiao; Li, Guoqing; Zhang, Guoliang

2015-10-01

Polysulfone (PSF) membranes have been widely applied in water and wastewater treatment, food-processing and biomedical fields. In this study, we report the preparation of modified PSF membranes by blending PSF with Cu2O nanowires (NWs) to improve their stability and antifouling activity. Synthesis of novel Cu2O NWs/PSF-blended ultrafiltration membrane was achieved via phase inversion method by dispersing one-dimensional Cu2O nanowires in PSF casting solutions. Various techniques such as XRD, SEM, TEM, and EDS were applied to characterize and investigate the properties of nanowires and membranes. The introduced Cu2O nanowires can firmly be restricted into micropores of PSF membranes, and therefore, they can effectively prevent the serious leaking problem of inorganic substances in separation process. The blended PSF membranes also provided enhanced antimicrobial activity and superior permeation property compared to pure PSF membrane. The overall work can not only provide a new way for preparation of novel blended membranes with multidimensional nanomaterials, but can also be beneficial to solve the annoying problem of biofouling.

The use of D-penicillamine in patients with rheumatoid arthritis undergoing hemodialysis.

PubMed

Matthey, F; Perrett, D; Greenwood, R N; Baker, L R

1986-05-01

D-penicillamine and its major metabolites cysteine-penicillamine disulphide (CP) and penicillamine disulphide (P2) concentrations were measured in plasma from a hemodialysis patient with rheumatoid arthritis. CP and P2 alone were measured in plasma and a plasma ultrafiltrate from a second patient. On penicillamine 250 mg thrice weekly taken after dialysis pre-dialysis penicillamine concentrations were in the range 5.9-9.9 mumol/l. CP and P2 concentrations remained stable (range 139-197 mumol/l and 10-20 mumol/l) over 5 weeks and were of the same order as previously found in patients with normal renal function on higher doses of the drug. On penicillamine 250 mg daily concentrations of metabolites CP and P2 reach 193 mumol/l and 59.2 mumol/l after 2 and 3 weeks respectively. Concentration of metabolites fell by about half and of penicillamine by about a third after dialysis. Concentration of metabolites in ultrafiltrate were on average 75% lower than in plasma. Penicillamine 250 mg thrice weekly given after dialysis appears to be an appropriate dose for hemodialysis patients with rheumatoid arthritis.

An in vitro study of interactions between insulin-mimetic zinc(II) complexes and selected plasma components.

PubMed

Enyedy, Eva Anna; Horváth, László; Gajda-Schrantz, Krisztina; Galbács, Gábor; Kiss, Tamás

2006-12-01

The speciations of some potent insulin-mimetic zinc(II) complexes of bidentate ligands: maltol and 1,2-dimethyl-3-hydroxypyridinone with (O,O) and picolinic acid with (N,O) coordination modes, were studied via solution equilibrium investigations of the ternary complex formation in the presence of small relevant bioligands of the blood serum such as cysteine, histidine and citric acid. Results show that formation of the ternary complexes, especially with cysteine, is favoured at physiological pH range in almost all systems studied. Besides these low molecular mass binders, serum proteins among others albumin and transferrin can bind zinc(II) or its complexes. Accordingly, the distribution of zinc(II) between the small and high molecular mass fractions of the serum was also studied by ultrafiltration. Modelling calculations relating to the distribution of zinc(II), using the stability constants of the ternary complexes studied and those of the serum proteins reported in the literature, confirmed the ultrafiltration results, namely, the primary role of albumin in zinc(II) binding among the low and high molecular mass components of the serum.

Removal of Cu(II) in water by polymer enhanced ultrafiltration: Influence of polymer nature and pH.

PubMed

Kochkodan, Olga D; Kochkodan, Viktor M; Sharma, Virender K

2018-01-02

This study presents an efficient removal of Cu(II) in water using the polymer enhanced ultrafiltration (PEUF) method. Polymer of different molecular weight (MW) (polyethyleneimine (PEI), sodium lignosulfonates (SLS) and dextrans) were investigated to evaluate efficiency in removal of Cu(II) in water by the PEUF method. The decomposition of Cu(II)-polymer complex was also evaluated in order to reuse polymers. Cu(II) complexation depends on the MW of chelating polymer and the pH of feed solution. It was found that the Cu(II) rejection increased with the polymer dosage with high removal of Cu(II) when using PEI and SLS at a 10:20 (mg/mg) ratio ([Cu(II)]:[polymer]). It was found that the maximum chelating capacity was 15 mg of Cu(II) per 20 mg of PEI. The Cu(II)-PEI complex could be decomposed by acid addition and the polymer could be efficiently reused with multiple complexation-decomplexation cycles. A conceptual flow chart of the integrated process of efficient removal of Cu(II) by PEUF method is suggested.

Summary of the ultrafiltration, reverse osmosis, and adsorbents project

NASA Astrophysics Data System (ADS)

Colvin, C. M.; Roberts, R. C.; Williams, M. K.

1983-01-01

The design for a medium size (40 gal/min) ultrafiltration (UF) membrane unit includes a schematic diagram, capital and operating costs, a list and discussion of the radioisotopes tested and the results achieved, operating parameters, and characteristics of the available membrane configurations. The plant design for a reverse osmosis (RO) membrane unit includes a conceptual diagram, specifications for a RO unit producing 40 gal/min of permeated product, a list of radioisotopes tested on RO units and the rejections achieved, a discussion of the principal of RO, a discussion of the upper limits of cation and anion concentrations (there are no lower limits), a discussion of membrane configurations and porosities, a discussion of factors affecting membranes, a section on calculating the membrane area needed for a particular application, and capital and operating cost calculations. The design for an ion exchange pilot plant includes a schematic diagram; flow, resin, and column specifications; impurity limits; and operating and capital costs. A short theoretical discussion and process description are also included. The design retains flexibility so that application to a specific stream can be determined.

Recovery of Whey Proteins and Enzymatic Hydrolysis of Lactose Derived from Casein Whey Using a Tangential Flow Ultrafiltration Module

NASA Astrophysics Data System (ADS)

Das, Bipasha; Bhattacharjee, Sangita; Bhattacharjee, Chiranjib

2013-09-01

In this study, ultrafiltration (UF) of pretreated casein whey was carried out in a cross-flow module fitted with 5 kDa molecular weight cut-off polyethersulfone membrane to recover whey proteins in the retentate and lactose in the permeate. Effects of processing conditions, like transmembrane pressure and pH on permeate flux and rejection were investigated and reported. The polarised layer resistance was found to increase with time during UF even in this high shear device. The lactose concentration in the permeate was measured using dinitro salicylic acid method. Enzymatic kinetic study for lactose hydrolysis was carried out at three different temperatures ranging from 30 to 50 °C using β-galactosidase enzyme. The glucose formed during lactose hydrolysis was analyzed using glucose oxidase-peroxidase method. Kinetics of enzymatic hydrolysis of lactose solution was found to follow Michaelis-Menten model and the model parameters were estimated by Lineweaver-Burk plot. The hydrolysis rate was found to be maximum (with Vmax = 5.5091 mmol/L/min) at 30 °C.

Removal of antibiotic resistant E. coli in two Norwegian wastewater treatment plants and by nano- and ultra-filtration processes.

PubMed

Schwermer, Carsten Ulrich; Krzeminski, Pawel; Wennberg, Aina Charlotte; Vogelsang, Christian; Uhl, Wolfgang

2018-02-01

The effectivity of different treatment stages at two large wastewater treatment plants (WWTPs) located in Oslo, Norway, to remove antibiotic resistant Escherichia coli from municipal wastewater was investigated. The WWTPs were effective in reducing the total cultivable E. coli. The E. coli in WWTP samples were mainly resistant to ampicillin (6-27%) and trimethoprim-sulfamethoxazole (5-24%), and, to a lesser extent, tetracycline (3-14%) and ciprofloxacin (0-7%). In the first WWTP, a clear decrease in the percentage of E. coli resistant to these antibiotics was found, with the main removal occurring during physical/chemical treatment. In the second WWTP, the percentage of cultivable resistant E. coli did not display a considerable change. During laboratory-scale membrane filtration of WWTP effluents using ultrafiltration (UF) and nanofiltration (NF) membranes, all E. coli, including those resistant to antibiotics, were removed completely. The results imply that UF and NF processes are potent measures to remove antibiotic resistant bacteria (ARB) during post-treatment of WWTP effluents, thus reducing the potential spread of antibiotic resistance in the receiving aquatic environment.

Removal characteristics of anionic metals by micellar-enhanced ultrafiltration.

PubMed

Baek, Kitae; Kim, Bo-Kyong; Cho, Hyun-Jeong; Yang, Ji-Won

2003-05-30

Surfactant-based separation of Fe(CN)(6)(3-) and CrO(4)(2-) using regenerated cellulose membrane was studied in order to assess the potential of micellar-enhanced ultrafiltration for the remediation of wastewater or groundwater polluted with ferriccyanide and chromate. In the ferriccyanide/octadecylamine acetate (ODA) and chromate/ODA systems, removal of ferriccyanide increased from 73 to 92% and to 98%, and that of chromate from 64 to 97% and to >99.9% as the molar ratio of ODA to ferriccyanide and to chromate increased from 1 to 2 and to 3, respectively. In the ferriccyanide/chromate/ODA system, while the removal of ferriccyanide increased from 62 to 72% and to 93%, the removal of chromate from 20 to 38% and to 68% as the molar ratio of ferriccyanide:chromate:ODA increased from 1:1:1 to 1:1:2 and to 1:1:4, respectively. With the molar ratio of 1:1:6, the removal was >99.9 and 98% for chromate and ferriccyanide, respectively. Ferriccyanide ions were more easily bound to ODA micelles because the binding power of ferriccyanide was greater than that of chromate.

Bloodless pediatric cardiopulmonary bypass for a 3.2-kg patient whose parents are of Jehovah's Witness faith.

PubMed

Ratliff, Todd M; Hodge, Ashley B; Preston, Thomas J; Galantowicz, Mark; Naguib, Aymen; Gomez, Daniel

2014-06-01

Patients and parents of Jehovah's Witness (JW) faith present multiple challenges to a medical team, especially in the neonatal and pediatric population. The medical team must balance honoring the parents' request of not receiving blood products and fulfilling our commitment as advocates for the child's wellbeing. A multidisciplinary approach to cardiac surgery must be embraced for bloodless cardiopulmonary bypass (CPB) to be successful. At our institution, we have developed strategies and techniques for blood conservation that are used preoperatively, intraoperatively, and postoperatively for every CPB case with the goal of a bloodless procedure. These protocols include: preoperative erythropoietin, preoperative iron administration, selection of a CPB circuit specific to the patient's height and weight, acute normovolemic hemodilution, retrograde autologous prime and venous autologous prime, tranexamic acid administration, zero-balance ultrafiltration, flushing of the pump suckers post-CPB, modified ultrafiltration, and cell salvage. We present an 8-day-old, 3.2-kg patient of JW faith with aortic valve stenosis and regurgitation and a patent foramen ovale who underwent a bloodless left ventricle-to-aorta tunnel repair and aortic valve repair on CPB.

An endogenous factor enhances ferulic acid decarboxylation catalyzed by phenolic acid decarboxylase from Candida guilliermondii

PubMed Central

2012-01-01

The gene for a eukaryotic phenolic acid decarboxylase of Candida guilliermondii was cloned, sequenced, and expressed in Escherichia coli for the first time. The structural gene contained an open reading frame of 504 bp, corresponding to 168 amino acids with a calculated molecular mass of 19,828 Da. The deduced amino sequence exhibited low similarity to those of functional phenolic acid decarboxylases previously reported from bacteria with 25-39% identity and to those of PAD1 and FDC1 proteins from Saccharomyces cerevisiae with less than 14% identity. The C. guilliermondii phenolic acid decarboxylase converted the main substrates ferulic acid and p-coumaric acid to the respective corresponding products. Surprisingly, the ultrafiltrate (Mr 10,000-cut-off) of the cell-free extract of C. guilliermondii remarkably activated the ferulic acid decarboxylation by the purified enzyme, whereas it was almost without effect on the p-coumaric acid decarboxylation. Gel-filtration chromatography of the ultrafiltrate suggested that an endogenous amino thiol-like compound with a molecular weight greater than Mr 1,400 was responsible for the activation. PMID:22217315

Effect of ozone on biopolymers in biofiltration and ultrafiltration processes.

PubMed

Siembida-Lösch, Barbara; Anderson, William B; Wang, Yulang Michael; Bonsteel, Jane; Huck, Peter M

2015-03-01

The focus of this full-scale study was to determine the effect of ozone on biopolymer concentrations in biofiltration and ultrafiltration (UF) processes treating surface water from Lake Ontario. Ozonation was out of service for maintenance for 9 months, hence, it was possible to investigate ozone's action on biologically active carbon contactors (BACCs) and UF, in terms of biopolymer removal. Given the importance of biopolymers for fouling, this fraction was quantified using a chromatographic technique. Ozone pre-treatment was observed to positively impact the active biomass in biofilters. However, since an increase of the active biomass did not result in higher biopolymer removal, active biomass concentration cannot be a surrogate for biofiltration performance. It was evident that increasing empty bed contact time (EBCT) from 4 to 19 min only had a positive effect on biopolymer removal through BACCs when ozone was out of service. However, as a mass balance experiment showed, ozone-free operation resulted in higher deposition of biopolymers on a UF membrane and slight deterioration in its performance. Copyright © 2014 Elsevier Ltd. All rights reserved.

The evaluation of hollow-fiber ultrafiltration and celite concentration of enteroviruses, adenoviruses and bacteriophage from different water matrices.

PubMed

Rhodes, Eric R; Huff, Emma M; Hamilton, Douglas W; Jones, Jenifer L

2016-02-01

The collection of waterborne pathogen occurrence data often requires the concentration of microbes from large volumes of water due to the low number of microorganisms that are typically present in environmental and drinking waters. Hollow-fiber ultrafiltration (HFUF) has shown promise in the recovery of various microorganisms. This study has demonstrated that the HFUF primary concentration method is effective at recovering bacteriophage φX174, poliovirus, enterovirus 70, echovirus 7, coxsackievirus B4 and adenovirus 41 from large volumes of tap and river water with an average recovery of all viruses of 73.4% and 81.0%, respectively. This study also evaluated an effective secondary concentration method using celite for the recovery of bacteriophage and enteric viruses tested from HFUF concentrates of both matrices. Overall, the complete concentration method (HFUF primary concentration plus celite secondary concentration) resulted in a concentration factor of 3333 and average recoveries for all viruses from tap and river waters of 60.6% and 60.0%, respectively. Published by Elsevier B.V.

Effect of chymosin and salt reduction on the quality of ultrafiltrated white-salted cheese.

PubMed

Al-Otaibi, Mutlag M; Wilbey, R Andrew

2005-05-01

This study demonstrated that both chymosin and salt-in-moisture (SM) were important factors for proteolysis in the manufacture of ultrafiltrated white-salted cheese, with significant effects on water-soluble nitrogen and nitrogen soluble in trichloroacetic acid. In contrast, the levels of free amino acids were not significantly affected by chymosin and salt treatments. The cheeses made, using high levels of chymosin with low SM had lower levels of residual alpha(S1)- and beta-casein at the end of ripening. On texture profile analysis, the hardness and fracturability of the cheeses significantly increased with SM and decreased during ripening. Increases in chymosin significantly contributed to the overall weakening of the structure throughout ripening. Bitter flavour was detected after 12 weeks in the cheese made with the higher chymosin level and lower SM, which could be the result of accumulation of gamma-casein fractions. The sensory data indicated that the hedonic responses for low chymosin with low SM cheeses were good and acceptable in flavour, which may be due to the moderate levels of proteolysis products.

Production of Bakers' Yeast in Cheese Whey Ultrafiltrate †

PubMed Central

Champagne, C. P.; Goulet, J.; Lachance, R. A.

1990-01-01

A process for the production of bakers' yeast in whey ultrafiltrate (WU) is described. Lactose in WU was converted to lactic acid and galactose by fermentation. Streptococcus thermophilus was selected for this purpose. Preculturing of S. thermophilus in skim milk considerably reduced its lag. Lactic fermentation in 2.3×-concentrated WU was delayed compared with that in unconcentrated whey, and fermentation could not be completed within 60 h. The growth rate of bakers' yeast in fermented WU differed among strains. The rate of galactose utilization was similar for all strains, but differences in lactic acid utilization occurred. Optimal pH ranges for galactose and lactic acid utilization were 5.5 to 6.0 and 5.0 to 5.5, respectively. The addition of 4 g of corn steep liquor per liter to fermented WU increased cell yields. Two sources of nitrogen were available for growth of Saccharomyces cerevisiae: amino acids (corn steep liquor) and ammonium (added during the lactic acid fermentation). Ammonium was mostly assimilated during growth on lactic acid. This process could permit the substitution of molasses by WU for the industrial production of bakers' yeast. PMID:16348117

Influence of fertilizer draw solution properties on the process performance and microbial community structure in a side-stream anaerobic fertilizer-drawn forward osmosis - ultrafiltration bioreactor.

PubMed

Kim, Youngjin; Li, Sheng; Chekli, Laura; Phuntsho, Sherub; Ghaffour, Noreddine; Leiknes, TorOve; Shon, Ho Kyong

2017-09-01

In this study, a side-stream anaerobic fertilizer-drawn forward osmosis (FDFO) and ultrafiltration (UF) membrane bioreactor (MBR) hybrid system was proposed and operated for 55days. The FDFO performance was first investigated in terms of flux decline with various fertilizers draw solution. Flux decline was very severe with all fertilizers due to the absence of aeration and the sticky property of sludge. Flux recovery by physical cleaning varied significantly amongst tested fertilizers which seriously affected biofouling in FDFO via reverse salt flux (RSF). Besides, RSF had a significant impact on nutrient accumulation in the bioreactor. These results indicated that nutrient accumulation negatively influenced the anaerobic activity. To elucidate these phenomena, bacterial and archaeal community structures were analyzed by pyrosequencing. Results showed that bacterial community structure was affected by fertilizer properties with less impact on archaeal community structure, which resulted in a reduction in biogas production and an increase in nitrogen content. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structure and rheological behavior of casein micelle suspensions during ultrafiltration process

NASA Astrophysics Data System (ADS)

Pignon, F.; Belina, G.; Narayanan, T.; Paubel, X.; Magnin, A.; Gésan-Guiziou, G.

2004-10-01

The stability and mechanism underlying the formation of deposits of casein micelles during ultrafiltration process were investigated by small-angle and ultra small-angle x-ray scattering (SAXS and USAXS). The casein micelle dispersions consisted of phospho-caseinate model powders and the measurements probed length scales ranging from 1 to 2000 nm. Rheometric and frontal filtration measurements were combined with SAXS to establish the relationship between the rheological behavior of deposits (shear and/or compression) and the corresponding microstructure. The results revealed two characteristic length scales for the equilibrium structure with radius of gyrations Rg, about 100 and 5.6 nm pertaining to the globular micelles and their non-globular internal structure, respectively. The SAXS measurements further indicated that the increase of temperature from 20 to 70 °C or the decrease of pH from 6.6 to 6 lead to agglomeration of the globular micelles. In situ scattering measurements showed that the decrease of permeation flows is directly related to the deformation and compression of the micelles in the immediate vicinity of the membrane.

Permeability-Selectivity Analysis of Microfiltration and Ultrafiltration Membranes: Effect of Pore Size and Shape Distribution and Membrane Stretching.

PubMed

Siddiqui, Muhammad Usama; Arif, Abul Fazal Muhammad; Bashmal, Salem

2016-08-06

We present a modeling approach to determine the permeability-selectivity tradeoff for microfiltration and ultrafiltration membranes with a distribution of pore sizes and pore shapes. Using the formulated permeability-selectivity model, the effect of pore aspect ratio and pore size distribution on the permeability-selectivity tradeoff of the membrane is analyzed. A finite element model is developed to study the effect of membrane stretching on the distribution of pore sizes and shapes in the stretched membrane. The effect of membrane stretching on the permeability-selectivity tradeoff of membranes is also analyzed. The results show that increasing pore aspect ratio improves membrane performance while increasing the width of pore size distribution deteriorates the performance. It was also found that the effect of membrane stretching on the permeability-selectivity tradeoff is greatly affected by the uniformity of pore distribution in the membrane. Stretching showed a positive shift in the permeability-selectivity tradeoff curve of membranes with well-dispersed pores while in the case of pore clustering, a negative shift in the permeability-selectivity tradeoff curve was observed.

Studies on a novel approach for the separation of L-phenylalanine amino acid from fermentation broth using a newly developed charged ultrafiltration membrane. I. Single solute system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agarwal, A.K.; Huang, R.Y.M.

A newly developed thin-film composite (TFC) ultrafiltration membrane made of sulfonated poly(phenylene oxide) (SPPO) was used to establish the feasibility of separating L-phenylalanine from the fermentation broth containing a number of dissolved inorganic and organic solutes as an alternative approach to the currently used complex and uneconomical conventional ion-exchange schemes. It was found that the rejection of inorganic salts in a single component system was highly dependent on the feed solution concentration and varied inversely with it. The pH of the feed solution was found to have a strong effect on the rejection of L-phenylalanine, changing it from - 10more » to 90%. This rejection behavior was identical for the two TFC-SPPO membrane samples which had molecular weight cutoff ratings of 10,000 and 20,000, respectively, although the permeate flux of the latter sample was almost twice that of the former sample. It was found that glucose molecules were not rejected by the membrane. 11 refs., 18 figs., 2 tab.« less

High Concentration Protein Ultrafiltration: a Comparative Fouling Assessment

NASA Astrophysics Data System (ADS)

Lim, Y. P.; Mohammad, A. W.

2018-05-01

In this paper, the predominant fouling mechanism via pH manipulation in gelatin ultrafiltration (UF) at constant operating pressure was studied. Two 30 kDa molecular weight cut off (MWCO) UF membranes with different hydrophilic/hydrophobic properties were tested at solution pH near gelatin isoelectric point (IEP), pH below and above gelatin’s IEP. The resistance-in-series model was used to determine quantitatively the contribution of each filtration resistance occurred during gelatin UF. The governing fouling mechanisms were investigated using classical blocking laws. The results demonstrated that concentration polarization remain as dominant fouling resistance in gelatin UF, but exceptional case was observed at pH away from gelatin’s IEP, showing that combined reversible and irreversible fouling resistances contributed around 57% and 37%, respectively to the overall fouling resistances. Under all experimental condition tested, permeate flux decline was accurately predicted by all the models studied. Fouling profile was fitted well with “Standard Blocking”, “Intermediate Blocking” and “Cake Filtration” model for regenerated cellulose acetate (RCA) membrane and “Cake Filtration” model for polyethersulphone (PES) membrane.

Effect of ultrasound pretreatment and Maillard reaction on structure and antioxidant properties of ultrafiltrated smooth-hound viscera proteins-sucrose conjugates.

PubMed

Abdelhedi, Ola; Mora, Leticia; Jemil, Ines; Jridi, Mourad; Toldrá, Fidel; Nasri, Moncef; Nasri, Rim

2017-09-01

The effect of ultrasound (US) pre-treatment on the evolution of Maillard reaction (MR), induced between low molecular weight (LMW) peptides and sucrose, was studied. LMW peptides (<1kDa) were obtained by the ultrafiltration of smooth hound viscera protein hydrolysates, produced by Neutrase, Esperase and Purafect. MR was induced by heating the LMW peptides in the presence of sucrose for 2h at 90°C, without or with US pre-treatment. During the reaction, a marked decrease in pH values, coupled to the increase in colour of the Maillard reaction products (MRPs), were recorded. In addition, after sonication, the glycation degree was significantly enhanced in Esperase-derived peptides/sucrose conjugates (p<0.05). Moreover, results showed that thermal heating, particularly after US treatment, reduced the bitter taste and enhanced the antioxidant capacities of the resulting conjugates. Hence, it could be concluded that US leads to efficient mixing of sugar-protein solution and efficient heat/mass transfer, contributing to increase the MR rate. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preparation and characterization of novel zwitterionic poly(arylene ether sulfone) ultrafiltration membrane with good thermostability and excellent antifouling properties

NASA Astrophysics Data System (ADS)

Rong, Guolong; Zhou, Di; Han, Xiaocui; Pang, Jinhui

2018-01-01

Zwitterionic poly(arylene ether sulfone) (PAES-NS) was synthesized via copolymerization by using a bisphenol monomer with a pyridine group. The chemical structures of the copolymers were confirmed by using Fourier transform infrared (FTIR) and 1H nuclear magnetic resonance (NMR) spectroscopy; the copolymers showed good thermal stability. A series of polyphenysulfone (PPSU)/PAES-NS blend ultrafiltration (UF) membranes was prepared via conventional immersion precipitation phase inversion methods The morphologies of the modified membranes were investigated by scanning electron microscopy (SEM). The surface hydrophilicity of the UF membranes was studied by water contact angle measurement, indicating that the zwitterionic group increased the membrane hydrophilicity. UF of solvated model pollutants using the membranes showed a significant reduction of the irreversible adsorption of the foulants, illustrating the excellent anti-fouling properties of the membrane. The water flux of the PAES-NS membrane was significantly enhanced, being almost three times higher than that of the pristine PPSU membrane, with retention of a high rejection level. After three UF cycles, the water flux recovery of the PAES-NS membrane was as high as 96%.

Biological and structural analyses of bovine heparin fractions of intermediate and high molecular weight.

PubMed

Nogueira, Alexsandro V; Drehmer, Daiana L; Iacomini, Marcello; Sassaki, Guilherme L; Cipriani, Thales R

2017-02-10

Low molecular weight heparin, which is generally obtained by chemical and enzymatic depolymerization of unfractionated heparin, has high bioavailability and can be subcutaneously injected. The aim of the present investigation was to fractionate bovine heparin using a physical method (ultrafiltration through a 10kDa cut-off membrane), avoiding structural modifications that can be caused by chemical or enzymatic treatments. Two fractions with different molecular weights were obtained: the first had an intermediate molecular weight (B-IMWH; Mn=9587Da) and the other had a high molecular weight (B-HMWH; 22,396Da). B-IMWH and B-HMWH have anticoagulant activity of 103 and 154IU/mg respectively, which could be inhibited by protamine. Both fractions inhibited α-thrombin and factor Xa in vitro and showed antithrombotic effect in vivo. Moreover, ex vivo aPTT assay demonstrated that B-IMWH is absorbed by subcutaneous route. The results showed that ultrafiltration can be used to obtain two bovine heparin fractions, which differ on their molecular weights, structural components, anticoagulant potency, and administration routes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Polyethersulfone-based ultrafiltration hollow fibre membrane for drinking water treatment systems

NASA Astrophysics Data System (ADS)

Chew, Chun Ming; Ng, K. M. David; Ooi, H. H. Richard

2017-12-01

Conventional media/sand filtration has been the mainstream water treatment process for most municipal water treatment plants in Malaysia. Filtrate qualities of conventional media/sand filtration are very much dependent on the coagulation-flocculation process prior to filtration and might be as high as 5 NTU. However, the demands for better quality of drinking water through public piped-water supply systems are growing. Polymeric ultrafiltration (UF) hollow fibre membrane made from modified polyethersulfone (PES) material is highly hydrophilic with high tensile strength and produces excellent quality filtrate of below 0.3 NTU in turbidity. This advanced membrane filtration material is also chemical resistance which allows a typical lifespan of 5 years. Comparisons between the conventional media/sand filtration and PES-based UF systems are carried out in this paper. UF has been considered as the emerging technology in municipal drinking water treatment plants due to its consistency in producing high quality filtrates even without the coagulation-flocculation process. The decreasing cost of PES-based membrane due to mass production and competitive pricing by manufacturers has made the UF technology affordable for industrial-scale water treatment plants.

Technical and economical evaluation of water recycling in the carwash industry with membrane processes.

PubMed

Boussu, K; Eelen, D; Vanassche, S; Vandecasteele, C; Van der Bruggen, B; Van Baelen, G; Colen, W; Vanassche, S

2008-01-01

In the carwash industry, water recycling is necessary to be in accordance with present and upcoming environmental laws. As this is not possible with traditional techniques, membrane processes (like ultrafiltration (UF) and nanofiltration (NF)) are technically and economically evaluated in this study. Concerning the technical part, there needs to be a compromise between a high permeate permeability on the one hand and a high permeate purity on the other hand. Depending on the use of the purified wastewater, ultrafiltration (to recycle wastewater in the main wash cycle) or nanofiltration (to recycle wastewater in the rinsing step) would be the optimal choice. Concerning the financial part, the implementation of membrane processes in the wastewater purification installation is economically feasible, especially when expensive tap water is used as pure water. These positive evaluations imply that membrane processes can be useful to recycle wastewater in the carwash industry, on condition that the right membrane type (with the least membrane fouling) and the right process format (e.g., hybrid process of UF and/or NF with a biological treatment) is selected. Copyright IWA Publishing 2008.

Behavior of pharmaceuticals and drugs of abuse in a drinking water treatment plant (DWTP) using combined conventional and ultrafiltration and reverse osmosis (UF/RO) treatments.

PubMed

Boleda, M A Rosa; Galceran, M A Teresa; Ventura, Francesc

2011-06-01

The behavior along the potabilization process of 29 pharmaceuticals and 12 drugs of abuse identified from a total of 81 compounds at the intake of a drinking water treatment plant (DWTP) has been studied. The DWTP has a common treatment consisting of dioxychlorination, coagulation/flocculation and sand filtration and then water is splitted in two parallel treatment lines: conventional (ozonation and carbon filtration) and advanced (ultrafiltration and reverse osmosis) to be further blended, chlorinated and distributed. Full removals were reached for most of the compounds. Iopromide (up to 17.2 ng/L), nicotine (13.7 ng/L), benzoylecgonine (1.9 ng/L), cotinine (3.6 ng/L), acetaminophen (15.6 ng/L), erythromycin (2.0 ng/L) and caffeine (6.0 ng/L) with elimination efficiencies ≥ 94%, were the sole compounds found in the treated water. The advanced treatment process showed a slightly better efficiency than the conventional treatment to eliminate pharmaceuticals and drugs of abuse. Copyright © 2011 Elsevier Ltd. All rights reserved.

Serum level of vascular endothelial growth factor is influenced by erythropoietin treatment in peritoneal dialysis patients. (Grupo de Estudios Peritoneales de Madrid).

PubMed

del Peso, G; Selgas, R; Bajo, M A; Fernández de Castro, M; Aguilera, A; Cirugeda, A; Jiménez, C

2000-01-01

Some patients on long-term peritoneal dialysis (PD) develop a hyperpermeability state, owing to peritoneal neoangiogenesis. Vascular endothelial growth factor (VEGF), a potent mitogen for endothelial cells, has been implicated in most diseases characterized by microvascular neoformation. Erythropoietin (EPO) is able to induce endothelial proliferation in vitro. Our aim was to elucidate whether VEGF serum levels are influenced by EPO treatment, and whether VEGF serum level maintains a relationship with peritoneal transport data. We analyzed serum levels of VEGF in 35 PD patients (18 males, 17 females). Mean age was 58 years, with a mean time on PD of 98 +/- 75 months. Of the 35 patients, 19 were on automated peritoneal dialysis, and 16 were on continuous ambulatory peritoneal dialysis. Seven patients had diabetes. Peritoneal transport parameters were: urea mass transfer coefficient (MTC), 19.5 +/- 6.6 mL/min; creatinine MTC, 9.9 +/- 4.7 mL/min; net ultrafiltration, 491 +/- 166 mL per 4-hour dwell. Twenty seven patients were under therapy with recombinant human erythropoietin (rHuEPO). Mean serum VEGF levels were 347 +/- 203 pg/mL (range 66-857 pg/mL), with most patients in the normal range (60-700 pg/mL). VEGF levels did not correlate with age, sex, primary renal disease, diabetes, type of PD, time on PD, peritonitis, and cumulative glucose load. We found no correlation with urea MTC, creatinine MTC, ultrafiltration rate, or protein effluent levels. However, a significant negative correlation with residual renal function was seen (r = -0.39, p < 0.05). Patients treated with rHuEPO showed significantly higher serum levels of VEGF than non treated patients (375 +/- 220 pg/mL vs 251 +/- 75 pg/mL, p < 0.05), although they had similar residual renal function. We conclude that increased serum VEGF levels are associated with EPO treatment. Consequently, VEGF might have a role in the EPO effects found in PD patients. Whether both agents are related to peritoneal neoangiogenesis requires further research.

Evolution of mixed surfactant aggregates in solutions and at solid/solution interfaces

NASA Astrophysics Data System (ADS)

Zhang, Rui

Surfactant systems have been widely used in such as enhanced oil recovery, waste treatment and metallurgy, etc., in order to solve the problem of global energy crisis, to remove the pollutants and to generate novel energy resources. Almost all surfactant systems are invariably mixtures due to beneficial and economic considerations. The sizes and shapes of aggregates in solutions and at solid/solution interfaces become important, since the nanostructures of mixed aggregates determine solution and adsorption properties. A major hurdle in science is the lack of information on the type of complexes and aggregates formed by mixtures and the lack of techniques for deriving such information. Using techniques such as analytical ultracentrifuge, small angle neutron scattering, surface tension, fluorescence, cryo-TEM, light scattering and ultrafiltration, the nanostructures of aggregates of sugar based n-dodecyl-beta-D-maltoside (DM) and nonionic pentaethyleneglycol monododecyl ether or nonyl phenol ethoxylated decyl ether (NP-10) and their mixtures have been investigated to prove the hypothesis that the aggregation behavior is linked to packing of the surfactant governed by the molecular interactions as well as the molecular structures. The results from both sedimentation velocity and sedimentation equilibrium experiments suggest coexistence of two types of micelles in nonyl phenol ethoxylated decyl ether solutions and its mixtures with n-dodecyl-beta-D-maltoside while only one micellar species is present in n-dodecyl-beta-D-maltoside solutions, in good agreement with those from small angle neutron scattering, cryo-TEM, light scattering and ultrafiltration. Type I micelles were primary micelles at cmc while type II micelles were elongated micelles. On the other hand, the nanostructures of mixed surface aggregates have been quantitatively predicted for the first time using a modified packing index. As a continuation of the Somasundaran-Fuersteneau adsorption model, a modified one-step model has been developed to fully understand the adsorption behavior of surfactant mixtures and obtained thermodynamic information on aggregation number and standard free energy for surface aggregation. The findings are expected to provide fundamental basis for the design optimal surfactant schemes for desired purposes.

The effect of ultrafiltration with cardiopulmonary bypass on the removal of dabigatran from the circulation of adult pigs.

PubMed

DeNino, Walter F; Carter, Christopher B; Sievert, Alicia; Goss, Ashley; Toole, John M; Mukherjee, Rupak; Uber, Walter E

2016-07-01

Dabigatran etexilate is a direct thrombin inhibitor approved for use in patients with non-valvular atrial fibrillation. There is no currently available pharmacological therapy to reverse this renally cleared anticoagulant. Dabigatran has a low level of plasma protein binding and has been considered dialyzable. We used a pig model with renal artery ligation to exclude intrinsic drug excretion to examine the efficacy of ultrafiltration (UF) during cardiopulmonary bypass (CPB) for dabigatran removal. Dabigatran was intravenously infused (20 mg) in Yorkshire pigs (male, n=7, 70±1 kg) following renal artery ligation. CPB with UF was initiated after heparinization and continued until a total volume of 6 liters of UF effluent was removed. Serial labs, including dabigatran concentration, activated coagulation times (ACT), hematocrit and creatinine were drawn at intervals before the start of CPB and then incrementally during UF (0, 2, 4 and 6 L removed). Hemodialysis (HD) was performed on one animal following UF. Dabigatran concentration (ng/mL) rose from undetectable levels at baseline to 296±70 (p<0.05) at the conclusion of infusion, but dropped significantly upon administration of heparin (178±40, p<0.05). A further decrement in dabigatran concentration was observed from the administration of heparin to the start of CPB (to 135±28, p<0.05). Once on CPB, dabigatran remained stable, with the end UF (eUF) dabigatran concentration being 133±34. Dabigatran concentration in the UF effluent was measured in one animal and was 98.8, with 6 L of effluent having been removed. The total recovery of dabigatran was calculated to be less than 5%. Dabigatran concentrations also did not decrease appreciably with HD on CPB following UF. UF in conjunction with CPB was ineffective at removing dabigatran. Heparin demonstrated a dabigatran-lowering effect, suggesting a possible drug interaction or assay impairment. Based on these findings, emergent cardiac surgery with UF on cardiopulmonary bypass to remove dabigatran is not advisable. Alternative forms of drug removal or reversal must be identified. © The Author(s) 2015.

Coagulation and oxidation for controlling ultrafiltration membrane fouling in drinking water treatment: Application of ozone at low dose in submerged membrane tank.

PubMed

Yu, Wenzheng; Graham, Nigel J D; Fowler, Geoffrey D

2016-05-15

Coagulation prior to ultrafiltration (UF) is widely applied for treating contaminated surface water sources for potable supply. While beneficial, coagulation alone is unable to control membrane fouling effectively in many cases, and there is continuing interest in the use of additional, complementary methods such as oxidation in the pre-treatment of raw water prior to UF. In this study, the application of ozone at low dose in the membrane tank immediately following coagulation has been evaluated at laboratory-scale employing model raw water. In parallel tests with and without the application of ozone, the impact of applied ozone doses of 0.5 mg L(-1) and 1.5 mg L(-1) (approximately 0.18 mg L(-1) and 0.54 mg L(-1) consumed ozone, respectively) on the increase of trans-membrane pressure (TMP) was evaluated and correlated with the quantity and nature of membrane deposits, both as a cake layer and within membrane pores. The results showed that a dose of 0.5 mgO3 L(-1) gave a membrane fouling rate that was substantially lower than without ozone addition, while a dose of 1.5 mgO3 L(-1) was able to prevent fouling effects significantly (no increase in TMP). Ozone was found to decrease the concentration of bacteria (especially the concentration of bacteria per suspended solid) in the membrane tank, and to alter the nature of dissolved organic matter by increasing the proportion of hydrophilic substances. Ozone decreased the concentration of extracellular polymeric substances (EPS), such as polysaccharides and proteins, in the membrane cake layer; the reduced EPS and bacterial concentrations resulted in a much thinner cake layer, although the suspended solids concentration was much higher in the ozone added membrane tank. Ozone also decreased the accumulation and hydrophobicity of organic matter within the membrane pores, leading to minimal irreversible fouling. Therefore, the application of low-dose ozone within the UF membrane tank is a potentially important approach for fully mitigating membrane fouling. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Emergence of Slow Collective Oscillations in Neural Networks with Spike-Timing Dependent Plasticity

NASA Astrophysics Data System (ADS)

Mikkelsen, Kaare; Imparato, Alberto; Torcini, Alessandro

2013-05-01

The collective dynamics of excitatory pulse coupled neurons with spike-timing dependent plasticity is studied. The introduction of spike-timing dependent plasticity induces persistent irregular oscillations between strongly and weakly synchronized states, reminiscent of brain activity during slow-wave sleep. We explain the oscillations by a mechanism, the Sisyphus Effect, caused by a continuous feedback between the synaptic adjustments and the coherence in the neural firing. Due to this effect, the synaptic weights have oscillating equilibrium values, and this prevents the system from relaxing into a stationary macroscopic state.

Uranium aqueous speciation in the vicinity of the former uranium mining sites using the diffusive gradients in thin films and ultrafiltration techniques.

PubMed

Drozdzak, Jagoda; Leermakers, Martine; Gao, Yue; Elskens, Marc; Phrommavanh, Vannapha; Descostes, Michael

2016-03-24

The performance of the Diffusive Gradients in Thin films (DGT) technique with Chelex(®)-100, Metsorb™ and Diphonix(®) as binding phases was evaluated in the vicinity of the former uranium mining sites of Chardon and L'Ecarpière (Loire-Atlantique department in western France). This is the first time that the DGT technique with three different binding agents was employed for the aqueous U determination in the context of uranium mining environments. The fractionation and speciation of uranium were investigated using a multi-methodological approach using filtration (0.45 μm, 0.2 μm), ultrafiltration (500 kDa, 100 kDa and 10 kDa) coupled to geochemical speciation modelling (PhreeQC) and the DGT technique. The ultrafiltration data showed that at each sampling point uranium was present mostly in the 10 kDa truly dissolved fraction and the geochemical modelling speciation calculations indicated that U speciation was markedly predominated by CaUO2(CO3)3(2-). In natural waters, no significant difference was observed in terms of U uptake between Chelex(®)-100 and Metsorb™, while similar or inferior U uptake was observed on Diphonix(®) resin. In turn, at mining influenced sampling spots, the U accumulation on DGT-Diphonix(®) was higher than on DGT-Chelex(®)-100 and DGT-Metsorb™, probably because their performance was disturbed by the extreme composition of the mining waters. The use of Diphonix(®) resin leads to a significant advance in the application and development of the DGT technique for determination of U in mining influenced environments. This investigation demonstrated that such multi-technique approach provides a better picture of U speciation and enables to assess more accurately the potentially bioavailable U pool. Copyright © 2016 Elsevier B.V. All rights reserved.

Meta-Analysis of Ultrafiltration versus Diuretics Treatment Option for Overload Volume Reduction in Patients with Acute Decompensated Heart Failure.

PubMed

Barkoudah, Ebrahim; Kodali, Sindhura; Okoroh, Juliet; Sethi, Rosh; Hulten, Edward; Suemoto, Claudia; Bittencourt, Marcio Sommer

2015-05-01

Although diuretics are mainly used for the treatment of acute decompensated heart failure (ADHF), inadequate responses and complications have led to the use of extracorporeal ultrafiltration (UF) as an alternative strategy for reducing volume overloads in patients with ADHF. The aim of our study is to perform meta-analysis of the results obtained from studies on extracorporeal venous ultrafiltration and compare them with those of standard diuretic treatment for overload volume reduction in acute decompensated heart failure. MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials databases were systematically searched using a pre‑specified criterion. Pooled estimates of outcomes after 48 h (weight change, serum creatinine level, and all-cause mortality) were computed using random effect models. Pooled weighted mean differences were calculated for weight loss and change in creatinine level, whereas a pooled risk ratio was used for the analysis of binary all-cause mortality outcome. A total of nine studies, involving 613 patients, met the eligibility criteria. The mean weight loss in patients who underwent UF therapy was 1.78 kg [95% Confidence Interval (CI): -2.65 to -0.91 kg; p < 0.001) more than those who received standard diuretic therapy. The post-intervention creatinine level, however, was not significantly different (mean change = -0.25 mg/dL; 95% CI: -0.56 to 0.06 mg/dL; p = 0.112). The risk of all-cause mortality persisted in patients treated with UF compared with patients treated with standard diuretics (Pooled RR = 1.00; 95% CI: 0.64-1.56; p = 0.993). Compared with standard diuretic therapy, UF treatment for overload volume reduction in individuals suffering from ADHF, resulted in significant reduction of body weight within 48 h. However, no significant decrease of serum creatinine level or reduction of all-cause mortality was observed.

Meta-Analysis of Ultrafiltration versus Diuretics Treatment Option for Overload Volume Reduction in Patients with Acute Decompensated Heart Failure

PubMed Central

Barkoudah, Ebrahim; Kodali, Sindhura; Okoroh, Juliet; Sethi, Rosh; Hulten, Edward; Suemoto, Claudia; Bittencourt, Marcio Sommer

2015-01-01

Introduction Although diuretics are mainly used for the treatment of acute decompensated heart failure (ADHF), inadequate responses and complications have led to the use of extracorporeal ultrafiltration (UF) as an alternative strategy for reducing volume overloads in patients with ADHF. Objective The aim of our study is to perform meta-analysis of the results obtained from studies on extracorporeal venous ultrafiltration and compare them with those of standard diuretic treatment for overload volume reduction in acute decompensated heart failure. Methods MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials databases were systematically searched using a pre‑specified criterion. Pooled estimates of outcomes after 48 h (weight change, serum creatinine level, and all-cause mortality) were computed using random effect models. Pooled weighted mean differences were calculated for weight loss and change in creatinine level, whereas a pooled risk ratio was used for the analysis of binary all-cause mortality outcome. Results A total of nine studies, involving 613 patients, met the eligibility criteria. The mean weight loss in patients who underwent UF therapy was 1.78 kg [95% Confidence Interval (CI): −2.65 to −0.91 kg; p < 0.001) more than those who received standard diuretic therapy. The post-intervention creatinine level, however, was not significantly different (mean change = −0.25 mg/dL; 95% CI: −0.56 to 0.06 mg/dL; p = 0.112). The risk of all-cause mortality persisted in patients treated with UF compared with patients treated with standard diuretics (Pooled RR = 1.00; 95% CI: 0.64–1.56; p = 0.993). Conclusion Compared with standard diuretic therapy, UF treatment for overload volume reduction in individuals suffering from ADHF, resulted in significant reduction of body weight within 48 h. However, no significant decrease of serum creatinine level or reduction of all-cause mortality was observed. PMID:25626761

Renal ultrafiltration changes induced by focused US.

PubMed

Fischer, Krisztina; McDannold, Nathan J; Zhang, Yongzhi; Kardos, Magdolna; Szabo, Andras; Szabo, Antal; Reusz, Gyorgy S; Jolesz, Ferenc A

2009-12-01

To determine if focused ultrasonography (US) combined with a diagnostic microbubble-based US contrast agent can be used to modulate glomerular ultrafiltration and size selectivity. The experiments were approved by the animal care committee. The left kidney of 17 healthy rabbits was sonicated by using a 260-kHz focused US transducer in the presence of a microbubble-based US contrast agent. The right kidney served as the control. Three acoustic power levels were applied: 0.4 W (six rabbits), 0.9 W (six rabbits), and 1.7 W (five rabbits). Three rabbits were not treated with focused US and served as control animals. The authors evaluated changes in glomerular size selectivity by measuring the clearance rates of 3000- and 70,000-Da fluorescence-neutral dextrans. The creatinine clearance was calculated for estimation of the glomerular filtration rate. The urinary protein-creatinine ratio was monitored during the experiments. The authors assessed tubular function by evaluating the fractional sodium excretion, tubular reabsorption of phosphate, and gamma-glutamyltransferase-creatinine ratio. Whole-kidney histologic analysis was performed. For each measurement, the values obtained before and after sonication were compared by using the paired t test. Significant (P < .05) increases in the relative (ratio of treated kidney value/nontreated kidney value) clearance of small- and large-molecule agents and the urine flow rates that resulted from the focused US treatments were observed. Overall, 1.23-, 1.23-, 1.61-, and 1.47-fold enhancement of creatinine clearance, 3000-Da dextran clearance, 70 000-Da dextran clearance, and urine flow rate, respectively, were observed. Focal tubular hemorrhage and transient functional tubular alterations were observed at only the highest (1.7-W) acoustic power level tested. Glomerular ultrafiltration and size selectivity can be temporarily modified with simultaneous application of US and microbubbles. This method could offer new opportunities for treatment of renal disease.

On the suitability of refractometry for the analysis of glucose in blood-derived fluids.

PubMed

Zirk, K; Poetzschke, H

2004-07-01

Refractometry is the determination of the optical refractive index of a substance or a mixture of substances. It is a very sensitive method for the detection and quantification of dissolved analytes, but it is incapable of distinguishing between different analytes. The aim of this investigation was to determine the principle suitability of refractometry for the quantification of glucose (blood sugar) in blood and various blood fluids which can readily be obtained for medical diagnosis, in particular blood plasma, blood serum, and their ultrafiltrates. After the oral intake of freshly dissolved alpha-glucose, the in vivo blood contents of the alpha and beta anomers of glucose were found to be in an at least approximate equilibrium at all times. This observation is a prerequisite for a refractometrical determination of glucose due to the fact that both molecule forms have different refractive index increments. An assessment of the glucose content in untreated blood fluids was not possible, since no suitable relationship to the refractive index was found, most probably due to the influence of the many other substances present in blood on this parameter. However, after removal of certain macromolecules by ultrafiltration, value pairs showed a high level of correlation, providing the nominal molecular weight limit (cut-off) of the ultrafilter used possessed a maximum of 300 kDa. Besides macromolecules, the osmolality of the fluids undergoing measurement also proved to be a considerable interfering factor, particularly when values were outside the normal physiological range between 285 and 293 mmol/L. If a clinical application of this method is to be contemplated it is imperative (1) that blood cells are separated and removed, (2) that macromolecules present in plasma or serum are removed, e.g. by ultrafiltration, and (3) that beyond the results presented the influence of all small molecules other than glucose on the overall refractive index be determined and included in the calculation of analysis results.

The synthesis and characterization of environmentally-responsive water-swellable and water-soluble polymers for wastewater remediation

NASA Astrophysics Data System (ADS)

Armentrout, Rodney Scott

The primary research goal is the development of new polymeric materials that demonstrate the environmentally-responsive sequestration of common water foulants, including surfactants and oils. Water-swellable and water-soluble polymers have been synthesized, structurally characterized, and their physical properties have been determined. In addition, the ability of the materials to sequester model water foulants has been evaluated. Anionic crosslinked polymer networks of 2-acrylamido-2-methyl-1-propanesulfonic acid, acrylamide, and methylene bisacrylamide have been synthesized and characterized by determining the equilibrium water contents as a function of ionic content of the polymer network. The molar ratio of bound surfactant to ionic group was determined to be less than one for all hydrogels studied, indicating an ion-exchange binding mechanism with minimal hydrophobic interactions between bound and unbound surfactant molecules is responsible for surfactant binding. Cationic crosslinked cyclopolymer networks of N,N-diallyl- N-methyl amine (DAMA) and N,N,N,N-tetraallyl ammonium chloride (TAAC) have been synthesized and characterized by determining the equilibrium water content as a function of pH. A maximum in the equilibrium water content is observed for pH-6 when the polymer is fully ionized. The solubilization of a model water foulant, p-cresol, by the polymeric surfactant, Pluronic F127, has been studied via equilibrium dialysis, dynamic light scattering and ultrafiltration experiments. It has been shown that at 25°C p-cresol is readily solubilized by F127 since the polymeric surfactant exists in a multimer conformation. Ultrafiltration experiments have demonstrated that the polymer-foulant binding interactions are largely unaffected by shear in a hollow fiber membrane. Copolymers of the zwitterionic monomer, 3-(N,N-diallyl- N-methyl ammonio) propane sulfonate (DAMAPS) and N,N-diallyl- N,N-dimethylammonium chloride (DADMAC) (the DADS series) or the pH-responsive hydrophobic monomer, N,N-diallyl-N-methyl amine (DAMA) (the DAMS series) have been prepared in a 0.5 M NaCl aqueous solution using 2-hydroxy-1-[4-(hydroxy-ethoxy)phenyl]-2-methyl-1-propanone (Irgacure 2959) as the free-radical photoinitiator. 13C NMR data indicate that the resulting polymers maintain the five-membered ring structure in the cis conformation common to diallylammonium salts. Equilibrium dialysis experiments demonstrate that pH-responsive hydrophobic microdomain formation may be utilized to control the solubilization of the organic solute, p-cresol. Ultrafiltration experiments have demonstrated that the polymer-foulant binding interactions are largely unaffected by shear in a hollow fiber membrane. Macromolecular aggregates of the poly( N,N-diallyl-N-methyl amine)/p-cresol complexes lead to fouling of the ultrafiltration membrane. However, incorporation of the sulfobetaine moiety hinders the formation of the macroscopic structures and higher permeate flux rates are achieved. (Abstract shortened by UMI.)

PEP Integrated Test D Run Report Caustic and Oxidative Leaching in UFP-VSL-T02A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sevigny, Gary J.; Bredt, Ofelia P.; Burns, Carolyn A.

2009-12-11

Pacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). The Pretreatment Engineering Platform (PEP) was designed, constructed and operated as part of a plan to respond to issue M12, "Undemonstrated Leaching Processes" of the External Flowsheet Review Team (EFRT) issue response plan. The PEP is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, and slurry washing processes. Themore » PEP replicates the WTP leaching processes using prototypic equipment and control strategies. The PEP also includes non-prototypic ancillary equipment to support the core processing. Two operating scenarios are currently being evaluated for the ultrafiltration process (UFP) and leaching operations. The first scenario (Test B and D) has caustic leaching performed in the UFP-2 ultrafiltration feed vessels (i.e., vessel UFP-VSL-T02A in the PEP and vessels UFP-VSL-00002A and B in the WTP PTF). The second scenario (Test A) has caustic leaching conducted in the UFP-1 ultrafiltration feed preparation vessels (i.e., vessels UFP-VSL-T01A and B in the PEP and vessels UFP VSL-00001A and B in the WTP PTF). In Test D, 19M sodium hydroxide (NaOH, caustic) was added to the waste slurry in the UFP VSL T02 vessel after the solids were concentrated to ~20% undissolved solids. The NaOH was added to leach solid aluminum compounds (e.g., gibbsite, boehmite). Caustic addition is followed by heating to 85°C using direct injection of steam to accelerate the leach process. The main difference of Test D compared to Test B is that the leach temperature is 85°C for 24 hrs as compared to 100°C for 12 hours. The other difference is the Test D simulant had Cr in the simulant from the start of processing and Test B had Cr added to adjust the simulant composition after aluminum leaching. Following the caustic leach, the UFP-VSL-T02A vessel contents are cooled using the vessel cooling jacket. The slurry was then concentrated to 17 wt% undissolved solids and washed with inhibited water to remove NaOH and other soluble salts. Next, the slurry was oxidatively leached using sodium permanganate to solubilize chrome. The slurry was then washed to remove the dissolved chrome and concentrated.« less

Doripenem Treatment during Continuous Renal Replacement Therapy

PubMed Central

Wenisch, J. M.; Maier-Salamon, A.; Fritsch, A.; Saria, K.; Zuba, C.; Jilch, S.; Lemmerer, R.; Unger, M.; Jaehde, U.; Jäger, W.; Thalhammer, F.

2015-01-01

Doripenem is a broad-spectrum parenteral carbapenem with enhanced activity against Pseudomonas aeruginosa. While the initial dosing recommendation for renally competent patients and patients undergoing continuous renal replacement therapy (cRRT) was 500 mg every 8 h (q8h), the dose for renally competent patients was updated to 1 g q8h in June 2012. There are no updated data for the dosing of patients on continuous renal replacement therapy. The original dosing regimen for cRRT patients was based on nonseptic patients, while newer publications chose comparatively low target concentrations for a carbapenem. Thus, there is an urgent need for updated recommendations for dosing during cRRT. In the trial presented here, we included 13 oliguric septic patients undergoing cRRT in an intensive care setting. Five patients each were treated with hemodiafiltration or hemodialysis, while three patients received hemofiltration treatment. All patients received 1 g doripenem every 8 h. Doripenem concentrations in the plasma and ultrafiltrate were measured over 48 h. The mean hemofilter clearance was 36.53 ml/min, and the mean volume of distribution was 59.26 liters. The steady-state trough levels were found at 8.5 mg/liter, with no considerable accumulation. Based on pharmacokinetic and pharmacodynamic considerations, we propose a regimen of 1 g q8h, which may be combined with a loading dose of 1.5 to 2 g for critically ill patients. (This study has been registered with EudraCT under registration no. 2009-018010-18 and at ClinicalTrials.gov under registration no. NCT02018939.) PMID:26711775

Granular compaction by fluidization

NASA Astrophysics Data System (ADS)

Tariot, Alexis; Gauthier, Georges; Gondret, Philippe

2017-06-01

How to arrange a packing of spheres is a scientific question that aroused many fundamental works since a long time from Kepler's conjecture to Edward's theory (S. F. Edwards and R.B.S Oakeshott. Theory of powders. Physica A, 157: 1080-1090, 1989), where the role traditionally played by the energy in statistical problems is replaced by the volume for athermal grains. We present experimental results on the compaction of a granular pile immersed in a viscous fluid when submited to a continuous or bursting upward flow. An initial fluidized bed leads to a well reproduced initial loose packing by the settling of grains when the high enough continuous upward flow is turned off. When the upward flow is then turned on again, we record the dynamical evolution of the bed packing. For a low enough continuous upward flow, below the critical velocity of fluidization, a slow compaction dynamics is observed. Strikingly, a slow compaction can be also observed in the case of "fluidization taps" with bursts of fluid velocity higher than the critical fluidization velocity. The different compaction dynamics is discussed when varying the different control parameters of these "fluidization taps".

Accuracy of intravenous infusion pumps in continuous renal replacement therapies.

PubMed

Jenkins, R; Harrison, H; Chen, B; Arnold, D; Funk, J

1992-01-01

Most extracorporeal continuous renal replacement therapies (CRRT) require inflow pumping of either dialysate, filtrate replacement solution, or both. Outflow of spent dialysate and ultrafiltrate can be accomplished by gravity drainage or pump. Intravenous infusion pumps have been commonly used for these purposes, although little is known about the accuracy of these pumps. To evaluate accuracy of two different types of intravenous infusion pumps used in CRRT, we studied flow rates at nine different pressure variations in three piston type and three linear peristaltic pumps. The results showed that error of either pump was not different for flow rates of 4 and 16 ml/min. Both types of pumps were affected by fluid circuit pressures, although pressure conditions under which error was low were different for each pump type. The linear peristaltic pumps were most accurate under conditions of low pump inlet pressure, whereas piston pumps were most accurate under conditions of low pump pressure gradient (outlet minus inlet) of 0 or -100 mmHg. The magnitude of error outside these conditions was substantial, reaching 12.5% for the linear peristaltic pump when inlet pressure was -100 mmHg and outlet pressure was 100 mmHg. Error may be minimized in the clinical setting by choosing the pump type best suited for the pressure conditions expected for the renal replacement modality in use.

Fast and slow myosins as markers of muscle injury.

PubMed

Guerrero, M; Guiu-Comadevall, M; Cadefau, J A; Parra, J; Balius, R; Estruch, A; Rodas, G; Bedini, J L; Cussó, R

2008-07-01

The diagnosis of muscular lesions suffered by athletes is usually made by clinical criteria combined with imaging of the lesion (ultrasonography and/or magnetic resonance) and blood tests to detect the presence of non-specific muscle markers. This study was undertaken to evaluate injury to fast and slow-twitch fibres using specific muscle markers for these fibres. Blood samples were obtained from 51 non-sports people and 38 sportsmen with skeletal muscle injury. Western blood analysis was performed to determine fast and slow myosin and creatine kinase (CK) levels. Skeletal muscle damage was diagnosed by physical examination, ultrasonography and magnetic resonance and biochemical markers. The imaging tests were found to be excellent for detecting and confirming grade II and III lesions. However, grade I lesions were often unconfirmed by these techniques. Grade I lesions have higher levels of fast myosin than slow myosin with a very small increase in CK levels. Grade II and III lesions have high values of both fast and slow myosin. The evaluation of fast and slow myosin in the blood 48 h after the lesion occurs is a useful aid for the detection of type I lesions in particular, since fast myosin is an exclusive skeletal muscle marker. The correct diagnosis of grade I lesions can prevent progression of the injury in athletes undergoing continual training sessions and competitions, thus aiding sports physicians in their decision making.

Widespread afterslip and triggered slow slip events following the M7.8 Kaikoura earthquake, New Zealand

NASA Astrophysics Data System (ADS)

Wallace, L. M.; Hreinsdottir, S.; Hamling, I. J.; D'Anastasio, E.; Bartlow, N. M.

2017-12-01

Just after midnight on 14 Nov 2016 (NZ Local time), the M7.8 Kaikoura earthquake ruptured a complex sequence of strike-slip and reverse faults over an approximately 150 km length in the northeastern South Island of New Zealand (Hamling et al., 2017, Science). In the months following the earthquake, time-dependent inversions of InSAR observations and continuous and semi-continuous GPS measurements reveal up to 0.5 m of afterslip on the subduction interface beneath the northern South Island underlying the region of large coseismic slip on crustal faults in the M7.8 earthquake. The geodetic data also require significant afterslip on a subset of the crustal faults that ruptured in the earthquake, including the Needles, Jordan Thrust, and Kekerengu faults. Our best-fitting models also suggest significant afterslip on an offshore reverse fault, in a similar position to one inferred by Clark et al. (2017, EPSL) from coseismic coastal uplift data. The M7.8 earthquake also triggered widespread slow slip occurring over much of the Hikurangi subduction zone beneath the North Island. Immediately following the earthquake, continuous GPS sites operated by GeoNet (www.geonet.org.nz) along the North Island's east coast (above the Hikurangi subduction zone) detected several to 30 mm of eastward motion over the two-week period immediately following the M7.8 event. These sites are located 350-650 km from the M7.8 earthquake. Such large eastward motion along the North Island's east coast following the earthquake is consistent with the initiation of a large slow slip event along the shallow, offshore portion of the Hikurangi subduction zone. In addition to shallow slow slip (<15 km depth) triggered offshore the east coast, we also observe deeper slow slip (>30 km depth) triggered in the Kapiti region at the southern Hikurangi margin. The Kapiti SSE was still ongoing as of August 2017, although we expect it to finish before the end of 2017. Given the large distance of the shallow east coast SSE from the M7.8 earthquake, we suggest that the shallow SSE was more likely to be triggered by dynamic stress changes, while the deeper SSEs closer to the Mw 7.8 were more likely triggered by static stress changes.

Effect of a dam on the optical properties of different-sized fractions of dissolved organic matter in a mid-subtropical drinking water source reservoir.

PubMed

Sun, Qiyuan; Jiang, Juan; Zheng, Yuyi; Wang, Feifeng; Wu, Chunshan; Xie, Rong-Rong

2017-11-15

The presence of a dam on a river is believed to have a key role in affecting changes in the components of the chromophoric dissolved organic matter (CDOM) in reservoirs. However, questions remain about the mechanisms that control these changes. In this study, we used tangential ultrafiltration, fluorescence spectrum and phytoplankton cell density detection to explore the impacts of a dam on the CDOM components in the Shanzai Reservoir, a source of drinking water. The results demonstrated each CDOM size fraction comprised two main components, namely C1 (protein-like substance) and C2 (humic-like substance). The C1 content had a higher value in areas with slow flow than in the normal river channel, while the C2 contents were generally stable in the flow direction. The topography of the reservoir site affected the structure of the CDOM components based on changes in the hydraulic conditions caused by the dam. The variations in the CDOM components, hydraulic parameters and fluorescence indices in the river flow direction indicated that the contribution of the phytoplankton to the CDOM content increased as the distance to the dam decreased, phytoplankton metabolism enhanced C1 content of the 1-10kDa molecular weights range fraction. Further, the contributions of different phytoplankton biomass to C1 proved that the dam changed the hydraulic conditions, had secondary effects on the metabolism of the phytoplankton, and resulted in changes in the structure of the CDOM components. Copyright © 2017 Elsevier B.V. All rights reserved.

A Slow-moving Isaac Brings Flooding to Gulf States

NASA Image and Video Library

2012-08-30

Strong tropical storm Isaac continues to create havoc across the Gulf Coast, from eastern Texas to Florida. This infrared image from NASA Aqua spacecraft, was acquired at 2:41 p.m. CDT on Aug. 29, 2012.

Continuous Feedback and Macroscopic Coherence

NASA Technical Reports Server (NTRS)

Tombesi, Paolo; Vitali, David

1996-01-01

We show that a model, recently introduced for quantum nondemolition measurements of a quantum observable, can be adapted to obtain a measurement scheme which is able to slow down the destruction of macroscopic coherence due to the measurement apparatus.

Slow-onset and fast-onset symptom presentations in acute coronary syndrome (ACS): new perspectives on prehospital delay in patients with ACS.

PubMed

O'Donnell, Sharon; McKee, Gabrielle; Mooney, Mary; O'Brien, Frances; Moser, Debra K

2014-04-01

Patient decision delay is the main reason why many patients fail to receive timely medical intervention for symptoms of acute coronary syndrome (ACS). This study examines the validity of slow-onset and fast-onset ACS presentations and their influence on ACS prehospital delay times. A fast-onset ACS presentation is characterized by sudden, continuous, and severe chest pain, and slow-onset ACS pertains to all other ACS presentations. Baseline data pertaining to medical profiles, prehospital delay times, and ACS symptoms were recorded for all ACS patients who participated in a large multisite randomized control trial (RCT) in Dublin, Ireland. Patients were interviewed 2-4 days after their ACS event, and data were gathered using the ACS Response to Symptom Index. Only baseline data from the RCT, N = 893 patients, were analyzed. A total of 65% (n = 577) of patients experienced slow-onset ACS presentation, whereas 35% (n = 316) experienced fast-onset ACS. Patients who experienced slow-onset ACS were significantly more likely to have longer prehospital delays than patients with fast-onset ACS (3.5 h vs. 2.0 h, respectively, t = -5.63, df 890, p < 0.001). A multivariate analysis of delay revealed that, in the presence of other known delay factors, the only independent predictors of delay were slow-onset and fast-onset ACS (β = -.096, p < 0.002) and other factors associated with patient behavior. Slow-onset ACS and fast-onset ACS presentations are associated with distinct behavioral patterns that significantly influence prehospital time frames. As such, slow-onset ACS and fast-onset ACS are legitimate ACS presentation phenomena that should be seriously considered when examining the factors associated with prehospital delay. Copyright © 2014 Elsevier Inc. All rights reserved.

Fractionation of Exosomes and DNA using Size-Based Separation at the Nanoscale

NASA Astrophysics Data System (ADS)

Wunsch, Benjamin; Smith, Joshua; Wang, Chao; Gifford, Stacey; Brink, Markus; Bruce, Robert; Solovitzky, Gustavo; Austin, Robert; Astier, Yann

Exosomes, a key target of ``liquid biopsies'', are nano-vesicles found in nearly all biological fluids. Exosomes are secreted by eukaryotic and prokaryotic cells alike, and contain information about their originating cells, including surface proteins, cytoplasmic proteins, and nucleic acids. One challenge in studying exosome morphology is the difficulty of sorting exosomes by size and surface markers. Common separation techniques for exosomes include ultracentrifugation and ultrafiltration, for preparation of large volume samples, but these techniques often show contamination and significant heterogeneity between preparations. To date, deterministic lateral displacement (DLD) pillar arrays in silicon have proven an efficient technology to sort, separate, and enrich micron-scale particles including human parasites, eukaryotic cells, blood cells, and circulating tumor cells in blood; however, the DLD technology has never been translated to the true nanoscale, where it could function on bio-colloids such as exosomes. We have fabricated nanoscale DLD (nanoDLD) arrays capable of rapidly sorting colloids down to 20 nm in continuous flow, and demonstrated size sorting of individual exosome vesicles and dsDNA polymers, opening the potential for on-chip biomolecule separation and diagnosti

Decongestion: Diuretics and other therapies for hospitalized heart failure

PubMed Central

Vazir, Ali; Cowie, Martin R.

2016-01-01

Acute heart failure (AHF) is a potentially life-threatening clinical syndrome, usually requiring hospital admission. Often the syndrome is characterized by congestion, and is associated with long hospital admissions and high risk of readmission and further healthcare expenditure. Despite a limited evidence-base, diuretics remain the first-line treatment for congestion. Loop diuretics are typically the first-line diuretic strategy with some evidence that initial treatment with continuous infusion or boluses of high-dose loop diuretic is superior to an initial lower dose strategy. In patients who have impaired responsiveness to diuretics, the addition of an oral thiazide or thiazide-like diuretic to induce sequential nephron blockade can be beneficial. The use of intravenous low-dose dopamine is no longer supported in heart failure patients with preserved systolic blood pressure and its use to assist diuresis in patients with low systolic blood pressures requires further study. Mechanical ultrafiltration has been used to treat patients with heart failure and fluid retention, but the evidence-base is not robust, and its place in clinical practice is yet to be established. Several novel pharmacological agents remain under investigation. PMID:27056656

Analysis and Evaluation of the Inhibitory Mechanism of a Novel Angiotensin-I-Converting Enzyme Inhibitory Peptide Derived from Casein Hydrolysate.

PubMed

Tu, Maolin; Liu, Hanxiong; Zhang, Ruyi; Chen, Hui; Mao, Fengjiao; Cheng, Shuzhen; Lu, Weihong; Du, Ming

2018-04-25

Casein hydrolysates exert various biological activities, and the responsible functional peptides are being identified from them continuously. In this study, the tryptic casein hydrolysate was fractionated by an ultrafiltration membrane (3 kDa), and the peptides were identified by capillary electrophoresis-quadrupole-time-of-flight-tandem mass spectrometry. Meanwhile, in silico methods were used to analyze the toxicity, solubility, stability, and affinity between the peptides and angiotensin-I-converting enzyme (ACE). Finally, a new angiotensin-I-converting enzyme inhibitory (ACEI) peptide, EKVNELSK, derived from α s1 -casein (fragment 35-42) was screened. The half maximal inhibitory concentration value of the peptide is 5.998 mM, which was determined by a high-performance liquid chromatography method. The Lineweaver-Burk plot indicated that this peptide is a mixed-type inhibitor against ACE. Moreover, Discovery Studio 2017 R2 software was adopted to perform molecular docking to propose the potential mechanisms underlying the ACEI activity of the peptide. These results indicated that EKVNELSK is a new ACEI peptide identified from casein hydrolysate.

Membrane technology for the future treatment of paper mill effluents: chances and challenges of further system closure.

PubMed

Simstich, B; Oeller, H-J

2010-01-01

The pressure on the European paper industry to further close its water circuits has increased significantly during the past decade. Since the technologies of the past can no longer meet the requirements of the future, new water treatment methods have become necessary. A constant rise in the interest in membrane technology expressed by the European paper industry confirms that in the future this method will evolve into a key technology for continued water savings. The publication provides an overview of current and future applications of membrane plants in the European paper industry. A range of technologies is briefly presented together with their advantages and drawbacks, and the economic potential of membrane use is discussed. Among other topics, the authors take a look at the utilization of membrane filtration for treating internal circulation water, partial flows containing coating colours, and biologically treated effluents. The technologies addressed include ultrafiltration, nanofiltration and membrane bioreactor technology. Possible recovery and treatment routes for the concentrates produced by the nanofiltration of biologically treated effluents are examined and evaluated.

Discerning the role of mechanosensors in regulating proximal tubule function

PubMed Central

Weisz, Ora A.

2015-01-01

All cells in the body experience external mechanical forces such as shear stress and stretch. These forces are sensed by specialized structures in the cell known as mechanosensors. Cells lining the proximal tubule (PT) of the kidney are continuously exposed to variations in flow rates of the glomerular ultrafiltrate, which manifest as changes in axial shear stress and radial stretch. Studies suggest that these cells respond acutely to variations in flow by modulating their ion transport and endocytic functions to maintain glomerulotubular balance. Conceptually, changes in the axial shear stress in the PT could be sensed by three known structures, namely, the microvilli, the glycocalyx, and primary cilia. The orthogonal component of the force produced by flow exhibits as radial stretch and can cause expansion of the tubule. Forces of stretch are transduced by integrins, by stretch-activated channels, and by cell-cell contacts. This review summarizes our current understanding of flow sensing in PT epithelia, discusses challenges in dissecting the role of individual flow sensors in the mechanosensitive responses, and identifies potential areas of opportunity for new study. PMID:26662200

Fast-to-slow transformation and nuclear import/export kinetics of the transcription factor NFATc1 during electrostimulation of rabbit muscle cells in culture

PubMed Central

Kubis, Hans-Peter; Scheibe, Renate J; Meißner, Joachim D; Hornung, Gunther; Gros, Gerolf

2002-01-01

Contractile activity imposed by chronic electrical stimulation of a primary skeletal muscle cell culture grown on microcarriers over several days led to an increase of slow myosin heavy chain I (MHCI) and a decrease of fast MHCII expression at mRNA and protein levels, indicating an ongoing fast-to-slow transformation. Only patterns with periods of continuous stimulation of > 5 min in a 45 min cycle were capable of inducing a fibre type transformation, and this was independent of the applied stimulation frequency over the range 1-10 Hz. We have shown before that the calcineurin-NFATc1 signalling pathway is indispensable in mediating MHCI upregulation during fibre type transformation. Therefore, subcellular localization of NFATc1 was studied immunocytochemically. This revealed that only one stimulation train lasting for > 5 min was sufficient to induce nuclear import of this factor, which was about complete after 20 min of continuous stimulation. For both induction of NFATc1 import and MHCI mRNA upregulation, the minimum stimulation interval of > 5 min was sufficient and stimulation frequency was not crucial between 1 and 10 Hz. Repetition of stimulation cycles, with pauses (< 40 min) shorter than the time required for complete export of NFATc1, led to an accumulation of NFATc1 in the nuclei with each cycle and thus to an amplification of the transformation signal during extended periods of electrostimulation. The temporal behaviour of NFATc import/export appears to determine the effectiveness of various electrostimulation protocols in inducing fast-to-slow fibre transformation. PMID:12068044

Spatial and temporal evolution of stress and slip rate during the 2000 Tokai slow earthquake

NASA Astrophysics Data System (ADS)

Miyazaki, Shin'ichi; Segall, Paul; McGuire, Jeffery J.; Kato, Teruyuki; Hatanaka, Yuki

2006-03-01

We investigate an ongoing silent thrust event in the Tokai seismic gap along the Suruga-Nankai Trough, central Japan. Prior to the event, continuous GPS data from April 1996 to the end of 1999 show that this region displaced ˜2 cm/yr to the northwest relative to the landward plate. The GPS time series show an abrupt change in rate in mid-June 2000 that continues as of mid-2005. We model this transient deformation, which we refer to as the Tokai slow thrust slip event, as caused by slip on the interface between the Philippine Sea and Amurian plates. The spatial and temporal distribution of slip rate is estimated with Kalman filter based inversion methods. Our inversions reveal two slow subevents. The first initiated in late June 2000 slightly before the Miyake-jima eruption. The locus of slip then propagated southeast in the second half of 2000, with maximum slip rates of about 15 cm/yr through 2001. A second locus of slip initiated to the northeast in early 2001. The depth of the slip zone is about 25 km, which may correspond to the transition zone from a seismogenic to a freely sliding zone. The cumulative moment magnitude of the slow slip event up to November 2002 is Mw ˜ 6.8. We calculate shear stress changes on the plate interface from the slip histories. Stress change as a function of slip rate shows trajectories similar to that inferred for high-speed ruptures; however, the maximum velocity is 8 orders of magnitude less than in normal earthquakes.

Assessment of a Point-of-Use Ultrafiltration System for Turbidity and Microbial Pathogen Removal - Paper

EPA Science Inventory

U.S. EPA’s Office of Research and Development has been evaluating the performance of point-of-use (POU) devices designed for use in homes and small businesses for many years. In collaboration with the University of Cincinnati, a series of pilot-scale tests were conducted on a Ma...

Removal of Inorganic, Microbial, and Particulate Contaminants from a Fresh Surface Water: Village Marine Tec. Expeditionary Unit Water Purifier, Generation 1

EPA Science Inventory

The Village Marine Tec. Generation 1 Expeditionary Unit Water Purifier (EUWP) is a mobile skid-mounted system employing ultrafiltration (UF) and reverse osmosis (RO) to produce drinking water from a variety of different water quality sources. The UF components were evaluated to t...

DENDRIMER ENHANCED ULTRAFILTRATION. 1. RECOVERY OF CU(II) FROM AQUEOUS SOLUTIONS USING PAMAM DENDRIMERS WITH ETHYLENE DIAMINE CORE AND TERMINAL NH2 GROUPS (R829626)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Environmental Technology Verification Report; Removal of Microbial Contaminants in Drinking Water Dow Chemical Company - Water Solutions SFD-2880 Ultrafiltration Module

EPA Science Inventory

The Dow SFD-2880 UF module was tested for removal of microorganisms using live Cryptosporidium parvum oocysts, endospores of the bacteria Bacillus alrophaeus, and the MS2 coliphage virus according to the product-specific challenge testing requirements of the EPA Long-Term 2 Enhan...

Evaluation of Radial Flow Fluidized Filter (R3F) Followed by Microfiltration and Ultrafiltration Systems in Calimesa, California

EPA Science Inventory

U.S. EPA coordinated a field study with South Mesa Water Utility to look for treatment alternatives for California State Project Water in the small community of Calimesa, California. EPA evaluated the performance of a system comprised of Radial Flow Fluidized Filtration (R3f) fo...

Design of extraction system in BRing at HIAF

NASA Astrophysics Data System (ADS)

Ruan, Shuang; Yang, Jiancheng; Zhang, Jinquan; Shen, Guodong; Ren, Hang; Liu, Jie; Shangguan, Jingbing; Zhang, Xiaoying; Zhang, Jingjing; Mao, Lijun; Sheng, Lina; Yin, Dayu; Wang, Geng; Wu, Bo; Yao, Liping; Tang, Meitang; Cai, Fucheng; Chen, Xiaoqiang

2018-06-01

The Booster Ring (BRing), which is the key part of HIAF (High Intensity heavy ion Accelerator Facility) complex at IMP (Institute of Modern Physics, Chinese Academy of Sciences), can provide uranium (A / q = 7) beam with a wide extraction energy range of 200-800 MeV/u. To fulfill a flexible beam extraction for multi-purpose experiments, both fast and slow extraction systems will be accommodated in the BRing. The fast extraction system is used for extracting short bunched beam horizontally in single-turn. The slow extraction system is used to provide quasi-continuous beam by the third order resonance and RF-knockout scheme. To achieve a compact structure, the two extraction systems are designed to share the same extraction channel. The general design of the fast and slow extraction systems and simulation results are discussed in this paper.

Colour change of twig-mimicking peppered moth larvae is a continuous reaction norm that increases camouflage against avian predators

PubMed Central

Rowland, Hannah M.; Edmonds, Nicola; Saccheri, Ilik J.

2017-01-01

Camouflage, and in particular background-matching, is one of the most common anti-predator strategies observed in nature. Animals can improve their match to the colour/pattern of their surroundings through background selection, and/or by plastic colour change. Colour change can occur rapidly (a few seconds), or it may be slow, taking hours to days. Many studies have explored the cues and mechanisms behind rapid colour change, but there is a considerable lack of information about slow colour change in the context of predation: the cues that initiate it, and the range of phenotypes that are produced. Here we show that peppered moth (Biston betularia) larvae respond to colour and luminance of the twigs they rest on, and exhibit a continuous reaction norm of phenotypes. When presented with a heterogeneous environment of mixed twig colours, individual larvae specialise crypsis towards one colour rather than developing an intermediate colour. Flexible colour change in this species has likely evolved in association with wind dispersal and polyphagy, which result in caterpillars settling and feeding in a diverse range of visual environments. This is the first example of visually induced slow colour change in Lepidoptera that has been objectively quantified and measured from the visual perspective of natural predators. PMID:29158965

Colour change of twig-mimicking peppered moth larvae is a continuous reaction norm that increases camouflage against avian predators.

PubMed

Eacock, Amy; Rowland, Hannah M; Edmonds, Nicola; Saccheri, Ilik J

2017-01-01

Camouflage, and in particular background-matching, is one of the most common anti-predator strategies observed in nature. Animals can improve their match to the colour/pattern of their surroundings through background selection, and/or by plastic colour change. Colour change can occur rapidly (a few seconds), or it may be slow, taking hours to days. Many studies have explored the cues and mechanisms behind rapid colour change, but there is a considerable lack of information about slow colour change in the context of predation: the cues that initiate it, and the range of phenotypes that are produced. Here we show that peppered moth ( Biston betularia ) larvae respond to colour and luminance of the twigs they rest on, and exhibit a continuous reaction norm of phenotypes. When presented with a heterogeneous environment of mixed twig colours, individual larvae specialise crypsis towards one colour rather than developing an intermediate colour. Flexible colour change in this species has likely evolved in association with wind dispersal and polyphagy, which result in caterpillars settling and feeding in a diverse range of visual environments. This is the first example of visually induced slow colour change in Lepidoptera that has been objectively quantified and measured from the visual perspective of natural predators.