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Sample records for acetate membrane electrophoresis

  1. A simple cellulose acetate membrane-based small lanes technique for protein electrophoresis.

    PubMed

    Na, Na; Liu, Tingting; Yang, Xiaojun; Sun, Binjie; Ouyang, Jenny; Ouyang, Jin

    2012-08-01

    Combining electrophoresis with a cellulose acetate membrane-based technique, we developed a simple and low-cost method, named cellulose acetate membrane-based small lanes (CASL), for protein electrophoresis. A home-made capillary plotter controlled by a 3D moving stage was used to create milli-to-micro channels by printing poly(dimethylsiloxane) on to a hydrophilic cellulose acetate membrane. In the hydrophilic channels, 5 nL protein mixture was separated on the basis of electro-migration under an electric field. Compared with polyacrylamide gel electrophoresis (PAGE), CASL resulted in higher protein signal intensity for separation of mixtures containing the same mass of protein. The platform was easily fabricated at low cost (approx. $0.005 for each 1-mm-wide channel), and separation of three protein mixtures was completed in 15 min. Both electrophoresis time and potential affected the separation. Rather than chromatographic separation, this method accomplished application of microchannel techniques for cellulose acetate membrane-based protein electrophoresis. It has potential in proteomic analysis, especially for rapid, low-cost, and low-volume sample analysis in clinical diagnosis.

  2. A method for the identification of sulfated glycopeptide by two-dimensional electrophoresis on cellulose acetate membrane.

    PubMed

    Yokoyama, M; Tanaka, H; Yoshihara, S; Endo, M

    1986-04-01

    Two-dimensional electrophoresis on cellulose acetate membrane permits the clean separation of sulfated glycopeptide in a mixture of acidic glycans (glycosaminoglycans and acidic glycopeptides). Two systems were used. In system 1, 0.1 M pyridine-0.47 M formic acid buffer (pH 3.0) was used in the first and 0.1 M barium acetate (pH 8.0) in the second dimension. In system 2, 0.1 M pyridine-0.47 M formic acid buffer (pH 3.0) was used in the first and 0.1 M HCl in the second dimension. All of the acidic glycans on electrophoretogram were stained with alcian blue in 70% ethanol. On the other hand, sulfated glycans alone were made visible with alcian blue in 0.1 M HCl. Alcian blue in 70% ethanol or 0.1 M HCl, when combined with periodic acid-Schiff's reagent identified sulfated glycopeptides on cellulose acetate membrane.

  3. Occurrence of serum M-protein species in Japanese patients older than 50 years based on relative mobility in cellulose acetate membrane electrophoresis.

    PubMed

    Kurihara, Y; Shiba, K; Fukumura, Y; Kobayashi, I; Kamei, S

    2000-01-01

    We investigated the occurrence of serum M-protein species in 2,007 Japanese patients older than 50 years of age. All sera samples were analyzed by cellulose acetate membrane electrophoresis. The relative mobility of an M-protein band was calculated by dividing the migration distance of M protein by that of albumin. M proteins were found to be present in 71 of 2,007 cases (3.5%). Men 80-89 years old showed the highest occurrence of M proteins, 11.0%. The relative mobility of M-protein bands, especially the band of the IgA-type M protein, increased as the patient's age advanced. The patients had higher levels of the IgG-type M protein than healthy Japanese subjects. We found that the occurrence of M-protein species in Japanese patients increases with their age. The IgG-type M protein was most frequently expressed among other types. The mobility of the M protein was greater in older patients probably because of aging-related changes in the carbohydrate chain of immunoglobulins composing an M-protein molecule.

  4. A continuous acetic acid system for polyacrylamide gel electrophoresis of gliadins and other prolamines.

    PubMed

    Clements, R L

    1988-02-01

    A polyacrylamide gel electrophoresis system buffered by acetic acid alone was developed for electrophoresis of prolamines. When applied to gliadin electrophoresis, the acetic acid system produces more bands than does a conventional aluminum lactate-lactic acid system (using 12% acrylamide gels). The acetic acid system is relatively simple, requiring a single buffer component that is universally available in high purity.

  5. High-flux cellulose acetate membranes

    SciTech Connect

    Boeddeker, K.W.; Finken, H.; Wenzlaff, A.

    1981-01-01

    Three routes to increase the permeate flux of asymmetric cellulose diacetate membranes of the Loeb-Sourirajan type were investigated: increasing the hydrophilicity of the membranes; increasing their compaction stability, and employing a swelling agent which allows for higher solvent-to-polymer ratio in the casting solution. The effect of casting solution composition on flux and rejection of formamide-modified cellulose acetate membrane is included, illustrating the general capability of this membrane type as function of solvent concentration. Membranes of casting solution composition cellulose diacetate/acetone/formamide 23/52/25 were used as reference membranes in the work. 6 figures. (DP)

  6. Fabricating PFPE Membranes for Capillary Electrophoresis

    NASA Technical Reports Server (NTRS)

    Lee, Michael C.; Willis, Peter A.; Greer, Frank; Rolland, Jason

    2009-01-01

    A process has been developed for fabricating perfluoropolyether (PFPE) membranes that contain microscopic holes of precise sizes at precise locations. The membranes are to be incorporated into laboratory-on-a-chip microfluidic devices to be used in performing capillary electrophoresis. The present process is a modified version of part of the process, described in the immediately preceding article, that includes a step in which a liquid PFPE layer is cured into solid (membrane) form by use of ultraviolet light. In the present process, one exploits the fact that by masking some locations to prevent exposure to ultraviolet light, one can prevent curing of the PFPE in those locations. The uncured PFPE can be washed away from those locations in the subsequent release and cleaning steps. Thus, holes are formed in the membrane in those locations. The most straightforward way to implement the modification is to use, during the ultraviolet-curing step, an ultraviolet photomask similar to the photomasks used in fabricating microelectronic devices. In lieu of such a photomask, one could use a mask made of any patternable ultraviolet-absorbing material (for example, an ink or a photoresist).

  7. Electrospun cellulose acetate membrane for size separating and antibacterial screening of crude polysaccharides.

    PubMed

    Chumpol, Jiraporn; Siri, Sineenat

    2016-12-01

    This study aims to produce electrospun cellulose acetate (CA) membrane as the alternative supporting medium for a separation of crude polysaccharides by electrophoresis and a screening of their antibacterial activity. Among the tested conditions of fabrication, electrospun CA membrane at 57% porosity showed the best separation of each polysaccharide from the standard mixture and the crude extract of Aloe vera via electrophoresis. As compared with the commercial CA membrane, the produced electrospun CA membrane demonstrated more separated spots of polysaccharides. The antibacterial activity of the electrophoretic polysaccharide was also determined against Escherichia coli and Staphylococcus aureus as the inhibition zone after the bacterial culture agar was overlaid on the membrane and incubated for 24 h. The results of this study suggested the potential application of electrospun CA membrane combining with electrophoresis as a simple method for separating crude polysaccharides and screening for their antibacterial activity.

  8. Rapid electrophoresis and quantitation of haemoglobins on cellulose acetate

    PubMed Central

    Marengo-Rowe, A. J.

    1965-01-01

    A rapid and reproducible electrophoretic method for the separation and quantitation of haemoglobins on cellulose acetate is described. The accuracy of the method and its possible sources of error are discussed. The normal range for haemoglobin A2 by this method is 1% to 3% of the total haemoglobin concentration. Blood samples from 32 thalassaemic patients showed haemoglobin A2 values of 3·5% to 7%. Images PMID:5844210

  9. [Applicability of cellulose acetate electrophoresis of globin chains to thalassemia screening].

    PubMed

    Masala, B; Demuro, P; Dore, F; Formato, M; Longinotti, M; Tidore, M

    1981-07-15

    We considered the possible application of globin chain separation on cellulose acetate strips electrophoresis to thalassemia screening. The method shows good accuracy and reproducibility when compared with the chromatographic method on CM-cellulose. The electrophoretic method could be recommended as the simplest test of hemoglobin biosynthesis in countries where high incidence of thalassemic syndromes occurs.

  10. Tris-acetate polyacrylamide gradient gel electrophoresis for the analysis of protein oligomerization.

    PubMed

    Cubillos-Rojas, Monica; Schneider, Taiane; Sánchez-Tena, Susana; Bartrons, Ramon; Ventura, Francesc; Rosa, Jose Luis

    2016-02-01

    Here we report a new approach for studying protein oligomerization in cells using a single electrophoresis gel. We combined the use of a crosslinking reagent for sample preparation, such as glutaraldehyde, with the analysis of oligomers by Tris-acetate polyacrylamide gel electrophoresis. The use of a 3-15% Tris-acetate polyacrylamide gradient gel allows for the simultaneous analysis of proteins of masses ranging from 10 to 500 kDa. We showed the usefulness of this method for analyzing endogenous p53 oligomerization with high resolution and sensitivity in human cells. Oligomerization analysis was dependent on the crosslinker concentration used. We also showed that this method could be used to study the regulation of oligomerization. In all experiments, Tris-acetate polyacrylamide gel electrophoresis proved to be a robust, manageable, and cost- and time-efficient method that provided excellent results using a single gel. This approach can be easily extrapolated to the study of other oligomers. All of these features make this method a highly useful tool for the analysis of protein oligomerization.

  11. Supported Molecular Matrix Electrophoresis.

    PubMed

    Matsuno, Yu-Ki; Kameyama, Akihiko

    2015-01-01

    Mucins are difficult to separate using conventional gel electrophoresis methods such as SDS-PAGE and agarose gel electrophoresis, owing to their large size and heterogeneity. On the other hand, cellulose acetate membrane electrophoresis can separate these molecules, but is not compatible with glycan analysis. Here, we describe a novel membrane electrophoresis technique, termed "supported molecular matrix electrophoresis" (SMME), in which a porous polyvinylidene difluoride (PVDF) membrane filter is used to achieve separation. This description includes the separation, visualization, and glycan analysis of mucins with the SMME technique.

  12. Ketotifen controlled release from cellulose acetate propionate and cellulose acetate butyrate membranes.

    PubMed

    Sobral, Manuela C C M; Sobral, Abilio J F N; Guthrie, J T; Gil, M H

    2008-02-01

    Ketotifen was immobilised in cellulose acetate propionate (CAP) membranes and in cellulose acetate butyrate (CAB) membranes. The characteristics of each system were evaluated under a range of experimental conditions. The topography and uniformity of the membranes was assessed using scanning electron microscopy. The release characteristics associated with Ketotifen were monitored spectrophotometrically. The swelling capacity of the membranes was evaluated and attributed to the combined effects of diffusion and of complex dissociation, during swelling. The materials produced were able to provide controlled release of Ketotifen due to their controlled swelling behaviour and adequate release properties. The results showed that the release of Ketotifen from the CAB membranes is higher but the release from the CAP membranes is more uniform.

  13. Free-flow electrophoresis for fractionation of Arabidopsis thaliana membranes.

    PubMed

    Bardy, N; Carrasco, A; Galaud, J P; Pont-Lezica, R; Canut, H

    1998-06-01

    Highly purified tonoplast and plasma membrane vesicles were isolated from microsomes of Arabidopsis thaliana by preparative free-flow electrophoresis. The most electronegative fractions were identified as tonoplast using nitrate-inhibited Mg2+-ATPase as enzyme marker. The least electronegative fractions were identified as plasma membrane using glucan-synthase II, UDPG: sterol-glucosyl-transferase, and vanadate-inhibited Mg2+-ATPase as enzyme markers. Other membrane markers, latent inosine-5'-diphosphatase (Golgi), NADPH-cytochrome-c reductase (endoplasmic reticulum) and cytochrome-c oxidase (mitochondria) were recovered in the fractions intermediate between tonoplast and plasma membrane. Immunoblot analysis of membrane fractions by antibodies directed against tonoplast and plasma membrane proteins confirmed the nature and the purity of the isolated membranes. The cytoskeletal protein actin, which was also identified by immunoblotting, was found to be specifically attached to the plasma membrane vesicles. The structural and functional integrity of the isolated membranes from Arabidopsis thaliana is discussed in the light of results obtained for the location of receptors and enzymes, or for the determination of ligand binding activity.

  14. Fucoidan as an inhibitor of thermally induced collagen glycation examined by acetate electrophoresis.

    PubMed

    Pielesz, Anna; Paluch, Jadwiga

    2014-08-01

    Non-enzymatic glycation (Maillard reaction) in vitro could be a simple method to obtain glycoconjugates for studying their biological properties. Hence, fucoidan was retained by acetate electrophoresis indicating a strong interaction with the protein. A loss of colour in fucoidan bands was found for samples incubated with collagen as compared with samples of free fucoidan. Also under in vitro conditions at 100°C - simulating a sudden burn incident - fucoidan binds with collagen as a result of the Maillard reaction. In contrast, the colour of the fucoidan bands intensified for samples incubated with collagen, with the addition of glucose. Electrophoretic analyses were carried out after heating the samples to a temperature simulating a burn incident. The bands were found to intensify for samples incubated with collagen during a 30-day-long incubation. Thus, spontaneous in vitro glycation - i.e. without the addition of glucose - was confirmed. This process is highly intensified both by the temperature and time of incubation. For a sample incubated in vitro in a fucoidan solution containing glucose, glycation was confirmed in a preliminary FTIR and acetate electrophoresis examinations, occurring in collagen obtained from chicken skins. In particular, a new band emerging around 1746 cm(-1) was observed for above samples, as was its increasing intensity, as compared with samples without the addition of glucose. In the collagen glycation assay, while glucose reacts with collagen and forms cross-linked aggregates, fucoidan decreases the process of aggregation and recovery of native collagen.

  15. Continuous-flow electrophoresis: Membrane-associated deviations of buffer pH and conductivity

    NASA Technical Reports Server (NTRS)

    Smolka, A. J. K.; Mcguire, J. K.

    1978-01-01

    The deviations in buffer pH and conductivity which occur near the electrode membranes in continuous-flow electrophoresis were studied in the Beckman charged particle electrophoresis system and the Hanning FF-5 preparative electrophoresis instrument. The nature of the membranes separating the electrode compartments from the electrophoresis chamber, the electric field strength, and the flow rate of electrophoresis buffer were all found to influence the formation of the pH and conductivity gradients. Variations in electrode buffer flow rate and the time of electrophoresis were less important. The results obtained supported the hypothesis that a combination of Donnan membrane effects and the differing ionic mobilities in the electrophoresis buffer was responsible for the formation of the gradients. The significance of the results for the design and stable operation of continuous-flow electrophoresis apparatus was discussed.

  16. Comparative analysis of cellulose acetate hemoglobin electrophoresis and high performance liquid chromatography for quantitative determination of hemoglobin A2

    PubMed Central

    Khosa, Shafi Mohammad; Moinuddin, Moinuddin; Mehmood, Hassan Osman; Qamar, Khansa

    2015-01-01

    Background The present study is designed to evaluate the reliability and cost effectiveness of cellulose acetate Hb electrophoresis and high performance liquid chromatography (HPLC) in the determination of HbA2 levels. Methods The test population comprised 160 individuals divided into four groups: normal individuals, β-thalassemia trait (BTT) patients, iron deficiency anemia (IDA) patients, and co-morbid patients (BTT with IDA). HbA2 levels determined using cellulose acetate Hb electrophoresis and HPLC were compared. Results HbA2 levels were found to be diagnostic for classical BTT using either method. In co-morbid cases, both techniques failed to diagnose all cases of BTT. The sensitivity, specificity, and Youden's index for detection of the co-morbid condition was 69% and 66% for HPLC and cellulose acetate Hb electrophoresis, respectively. Conclusion This study revealed that semi-automated cellulose acetate Hb electrophoresis is more suitable for use in β-thalassemia prevention programs in low-income countries like Pakistan. This technique is easily available, simple and cost effective. PMID:25830130

  17. Ion selective permeation through cellulose acetate membranes in forward osmosis.

    PubMed

    Irvine, Gavin J; Rajesh, Sahadevan; Georgiadis, Michael; Phillip, William A

    2013-12-03

    Solute-solute interactions can have a dramatic impact on the permeation of solutes through dense polymeric membranes. In particular, understanding how solute-solute interactions can affect the design of osmotically driven membrane processes (ODMPs) is critical to the successful development of these emerging water treatment and energy generation processes. In this work, we investigate the influence that solute-solute interactions have on nitrate permeation through an asymmetric cellulose acetate forward osmosis membrane. A series of experiments that included systematic modifications to the cation paired with nitrate, the identity of the draw solute, and the solution pH were conducted. These experiments reveal that in the unique operating geometry of ODMPs, where solute containing solutions are present on both sides of the membrane, nitrate fluxes are significantly higher (>15 times in some cases) than predicted by existing models for solute permeation in ODMPs. The identity of the cation paired with nitrate influences the flux of nitrate; the identity of the cation in the draw solution does not affect the flux of nitrate; however, the identity of the anion in the draw solution has the most significant impact on the flux of nitrate. These results suggest that an ion exchange mechanism, which allows nitrate to switch rapidly with anions from the draw solution, is present when cellulose acetate based membranes are used in ODMPs.

  18. [Simultaneous determination of chlorhexidine acetate and benzalkonium chloride in compound chemical disinfectants by capillary electrophoresis].

    PubMed

    Song, Baohua; Ding, Xiaojing; Li, Jia; Wang, Zhi

    2012-09-01

    Benzalkonium chloride (BAC) is a mixture of alkyl substituted benzyl dimethylammonium chloride homologs (C12-BAC, C14-BAC and C16-BAC). Chlorhexidine acetate is a widely used effective component in compound chemical disinfectants. A method for the simultaneous determination of chlorhexidine acetate and benzalkonium chloride in compound chemical disinfectants by capillary electrophoresis (CE) was established. The CE analysis was carried out using an uncoated capillary with 50 microm i. d. and 37 cm total length. The running buffer was 150 mmol/L NaH2PO4-62.5 mmol/L H3PO4 (pH 2.5) containing 40% (v/v) acetonitrile. The sample medium was 50 mmol/L acetic acid-acetonitrile (1:1, v/v). The detection wavelength was 214 nm. The factors such as the buffer concentration and pH, the content of acetonitrile, which influenced the separation and accurate assay of compound chemical disinfectants were investigated in detail. The intra-day and inter-day precisions of the method were below 3. 0% and 3.7%, respectively. The limits of detection (LOD, signal to noise ratio (S/N) = 3) for chlorhexidine acetate, C12-BAC, Cl4-BAC and C16-BAC were 0. 3, 0.5, 0.5 and 0.5 mg/L, respectively. The limits of quantification (LOQ, S/N = 10) were 1.0, 1.5, 1.5, and 1.5 mg/L, respectively. The corrected peak area and the mass concentration of the four components mentioned above showed good linear relationships within the ranges of 1.0 - 400 mg/L, 1. 5 - 200 mg/L, 1.5 - 200 mg/L and 1.5 - 200 mg/L, with linear correlation coefficients (r) of 0.9995, 0.9998, 0.999 7 and 0.9998, respectively. The established method was used for the determination of the four disinfectants in the compound chemical disinfectants. The results were in good agreement with those obtained by the high performance liquid chromatographic method.

  19. Simple, rapid and, cost-effective fabrication of PDMS electrophoresis microchips using poly(vinyl acetate) as photoresist master.

    PubMed

    Lobo-Júnior, Eulício O; Gabriel, Ellen F M; Dos Santos, Rodrigo A; de Souza, Fabrício R; Lopes, Wanderson D; Lima, Renato S; Gobbi, Angelo L; Coltro, Wendell K T

    2017-01-01

    This study describes a simple, rapid, and cost-effective fabrication of PDMS electrophoresis microchips using poly(vinyl acetate) (PVAc) emulsion as photoresist master. High-relief microfluidic structures were defined on poly(vinyl acetate) previously deposited on printed circuit boards surfaces without cleanroom facilities and sophisticated instrumentation. After a UV exposure, channels with heights ranging from 30 to 140 μm were obtained by controlling the emulsion mass deposited on the master surface. The developing stage was performed using water rather than the organic solvents that are applied for conventional masks. The surface morphology was characterized by optical imaging, profilometry, and SEM. Based on the achieved results, the proposed method offers suitable reproducibility for the prototyping of electrophoresis microchips in PDMS. The feasibility of the resulting PDMS electrophoresis chips was successfully demonstrated with the separation of major inorganic cations within 100 s using a contactless conductivity detection system. The separation efficiencies ranged from ca. 67 900 to 125 600 plates/m. Due to the satisfactory performance and simplified instrumentation, we believe this fabrication protocol presents potential to be implemented in any chemical, biochemical, or biological laboratory.

  20. Enzymatic membranes for the selective transport of neutral molecules by electrophoresis.

    PubMed

    Perrin, Bernard; Couturier, Roger; Fiaty, Koffi; Charcosset, Catherine; Maïsterrena, Bernard

    2008-06-01

    The active and selective transport of glucose and glycerol was carried out using electrophoresis and artificial enzymatic membranes. These positively charged composite membranes carry, on the face adjacent to the donor compartment of an electrophoresis module, a specific kinase (hexokinase or glycerokinase) and, on the opposite face, an alkaline phosphatase (ALP). Phosphorylation of the neutral substrate (glucose or glycerol) on the donor side by the kinase generates a negatively charged phosphorylated substrate, whose transmembrane migration is promoted by an electric field and by the membrane's positive charge. Dephosphorylation of the phosphorylated substrate by ALP on the opposite face regenerates the neutral substrate, which accumulates in the receiver compartment of the electrophoresis module. Using an electrophoresis module specifically designed for this study, our experiments were carried out enabling glucose and glycerol to be concentrated approximately eight- and twelve-fold, respectively, in 8 h.

  1. Thiosulphate conversion in a methane and acetate fed membrane bioreactor.

    PubMed

    Suarez-Zuluaga, Diego A; Timmers, Peer H A; Plugge, Caroline M; Stams, Alfons J M; Buisman, Cees J N; Weijma, Jan

    2016-02-01

    The use of methane and acetate as electron donors for biological reduction of thiosulphate in a 5-L laboratory membrane bioreactor was studied and compared to disproportionation of thiosulphate as competing biological reaction. The reactor was operated for 454 days in semi-batch mode; 30 % of its liquid phase was removed and periodically replenished (days 77, 119, 166, 258, 312 and 385). Although the reactor was operated under conditions favourable to promote thiosulphate reduction coupled to methane oxidation, thiosulphate disproportionation was the dominant microbial process. Pyrosequencing analysis showed that the most abundant microorganisms in the bioreactor were phototrophic green sulphur bacteria (GSB) belonging to the family Chlorobiaceae and thiosulphate-disproportionating bacteria belonging to the genus Desulfocapsa. Even though the reactor system was surrounded with opaque plastic capable of filtering most of the light, the GSB used it to oxidize the hydrogen sulphide produced from thiosulphate disproportionation to elemental sulphur. Interrupting methane and acetate supply did not have any effect on the microbial processes taking place. The ultimate goal of our research was to develop a process that could be applied for thiosulphate and sulphate removal and biogenic sulphide formation for metal precipitation. Even though the system achieved in this study did not accomplish the targeted conversion using methane as electron donor, it does perform microbial conversions which allow to directly obtain elemental sulphur from thiosulphate.

  2. Surface modification of cellulose acetate membrane using thermal annealing to enhance produced water treatment

    SciTech Connect

    Kusworo, T. D. Aryanti, N. Firdaus, M. M. H.; Sukmawati, H.

    2015-12-29

    This study is performed primarily to investigate the effect of surface modification of cellulose acetate using thermal annealing on the enhancement of membrane performance for produced water treatment. In this study, Cellulose Acetate membranes were casted using dry/wet phase inversion technique. The effect of additive and post-treatment using thermal annealing on the membrane surface were examined for produced water treatment. Therma annealing was subjected to membrane surface at 60 and 70 °C for 5, 10 and 15 second, respectively. Membrane characterizations were done using membrane flux and rejection with produced water as a feed, Scanning Electron Microscopy (SEM) and Fourier Transform Infra Red (FTIR) analysis. Experimental results showed that asymmetric cellulose acetate membrane can be made by dry/wet phase inversion technique. The results from the Scanning Electron Microscopy (FESEM) analysis was also confirmed that polyethylene glycol as additivie in dope solution and thermal annealing was affected the morphology and membrane performance for produced water treatment, respectively. Scanning electron microscopy micrographs showed that the selective layer and the substructure of membrane became denser and more compact after the thermal annealing processes. Therefore, membrane rejection was significantly increased while the flux was slighty decreased, respectively. The best membrane performance is obtained on the composition of 18 wt % cellulose acetate, poly ethylene glycol 5 wt% with thermal annealing at 70° C for 15 second.

  3. Surface modification of cellulose acetate membrane using thermal annealing to enhance produced water treatment

    NASA Astrophysics Data System (ADS)

    Kusworo, T. D.; Aryanti, N.; Firdaus, M. M. H.; Sukmawati, H.

    2015-12-01

    This study is performed primarily to investigate the effect of surface modification of cellulose acetate using thermal annealing on the enhancement of membrane performance for produced water treatment. In this study, Cellulose Acetate membranes were casted using dry/wet phase inversion technique. The effect of additive and post-treatment using thermal annealing on the membrane surface were examined for produced water treatment. Therma annealing was subjected to membrane surface at 60 and 70 °C for 5, 10 and 15 second, respectively. Membrane characterizations were done using membrane flux and rejection with produced water as a feed, Scanning Electron Microscopy (SEM) and Fourier Transform Infra Red (FTIR) analysis. Experimental results showed that asymmetric cellulose acetate membrane can be made by dry/wet phase inversion technique. The results from the Scanning Electron Microscopy (FESEM) analysis was also confirmed that polyethylene glycol as additivie in dope solution and thermal annealing was affected the morphology and membrane performance for produced water treatment, respectively. Scanning electron microscopy micrographs showed that the selective layer and the substructure of membrane became denser and more compact after the thermal annealing processes. Therefore, membrane rejection was significantly increased while the flux was slighty decreased, respectively. The best membrane performance is obtained on the composition of 18 wt % cellulose acetate, poly ethylene glycol 5 wt% with thermal annealing at 70° C for 15 second.

  4. Capillary blotting of glycosaminoglycans on nitrocellulose membranes after agarose-gel electrophoresis separation.

    PubMed

    Volpi, Nicola; Maccari, Francesca

    2009-01-01

    A method for the blotting and immobilizing of several nonsulfated and sulfated complex polysaccharides on membranes made hydrophilic and positively charged by cationic detergent after their separation by conventional agarose gel electrophoresis is illustrated. This new approach to the study of glycosaminoglycans (GAGs) utilizes the capacity of agarose gel electrophoresis to separate single species of polysaccharides from mixtures and the membrane technology for further preparative and analytical uses.Nitrocellulose membranes are derivatized with the cationic detergent cetylpyridinium chloride and mixtures of GAGs are capillary blotted after their separation in agarose gel electrophoresis. Single purified species of variously sulfated polysaccharides are transferred on derivatized membranes with an efficiency of 100% and stained with alcian blue (irreversible staining) and toluidine blue (reversible staining). This enables a lower amount limit of detection of 0.1 microg. Nonsulfated polyanions, for example hyaluronic acid, may also be transferred to membranes with a limit of detection of approximately 0.1-0.5 microg after irreversible or reversible staining. The membranes may be stained with reversible staining and the same lanes are used for immunological detection or other applications.

  5. Physical properties and biocompatibility of cellulose/soy protein isolate membranes coagulated from acetic aqueous solution.

    PubMed

    Luo, Li-Hua; Wang, Xiao-Mei; Zhang, Yu-Feg; Liu, Yong-Ming; Chang, Peter R; Wang, Yan; Chen, Yun

    2008-01-01

    A series of cellulose/soy protein isolate (SPI) membranes was prepared from cellulose and SPI solution by casting and coagulation from 5 wt% acetic acid and 5 wt% sulphuric acid aqueous solution, respectively. The structure and properties of the membranes were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and tensile testing. The effects of SPI content (W(SPI)) and the coagulants on the structure and properties of the membranes were investigated. The membranes exhibited porous structure. The pore size in the surfaces and cross-sections of the membranes increased with an increase of W(SPI) regardless of the coagulants. The membranes containing 10 wt% W(SPI) showed higher tensile strength and elongation at break than other membranes. The membranes with the same W(SPI) coagulated from acetic acid solution exhibited higher values of tensile strength, elongation at break and pore size in the surfaces and cross-sections than those corresponding membranes coagulated from sulphuric acid. The biocompatibility of the acetic acid-coagulated membranes was preliminarily evaluated by cell culture and in vivo implantation experiments. The results revealed that human umbilical vein endothelial cells (ECV304) grew well on this biomaterial. In comparison with the pure cellulose membrane, because of the incorporation of SPI and the resultant alteration of microstructure, the SPI-modified membranes showed an improved in vivo biocompatibility and biodegradability in the implantation experiments. These cellulose/SPI membranes warrant further explorations in biomedical fields.

  6. Enhanced detergent extraction for analysis of membrane proteomes by two-dimensional gel electrophoresis

    PubMed Central

    Churchward, Matthew A; Butt, R Hussain; Lang, John C; Hsu, Kimberly K; Coorssen, Jens R

    2005-01-01

    Background The analysis of hydrophobic membrane proteins by two-dimensional gel electrophoresis has long been hampered by the concept of inherent difficulty due to solubility issues. We have optimized extraction protocols by varying the detergent composition of the solubilization buffer with a variety of commercially available non-ionic and zwitterionic detergents and detergent-like phospholipids. Results After initial analyses by one-dimensional SDS-PAGE, quantitative two-dimensional analyses of human erythrocyte membranes, mouse liver membranes, and mouse brain membranes, extracted with buffers that included the zwitterionic detergent MEGA 10 (decanoyl-N-methylglucamide) and the zwitterionic lipid LPC (1-lauroyl lysophosphatidylcholine), showed selective improvement over extraction with the common 2-DE detergent CHAPS (3 [(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate). Mixtures of the three detergents showed additive improvements in spot number, density, and resolution. Substantial improvements in the analysis of a brain membrane proteome were observed. Conclusion This study demonstrates that an optimized detergent mix, coupled with rigorous sample handling and electrophoretic protocols, enables simple and effective analysis of membrane proteomes using two-dimensional electrophoresis. PMID:15941475

  7. Synthesis and characterization of polyurethane-cellulose acetate blend membrane for chromium (VI) removal.

    PubMed

    Riaz, Tabinda; Ahmad, Adnan; Saleemi, Sidra; Adrees, Muhammad; Jamshed, Fahad; Hai, Abdul Moqeet; Jamil, Tahir

    2016-11-20

    Blended membranes of polyurethane and cellulose acetate were prepared, characterized and investigated for their performance. Various ratios of cellulose acetate were employed to prepare four different blend membranes. The characteristics of both pure and blend membranes were investigated and results were compared to distinguish their properties. Functional group analysis was carried out by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) of pure and blend samples. Contact angle measurement and water content were evaluated to determine the membrane hydrophilicity. Moreover, the membrane morphology was studied by scanning electron microscopy (SEM). The membrane permeation properties and ability to reject chromium (VI) ions were tested at various pH and pressure by utilizing different salt concentrations.

  8. Investigation of the pore structure and morphology of cellulose acetate membranes using small-angle neutron scattering. 1: Cellulose acetate active layer membranes

    SciTech Connect

    Kulkarni, S.; Krause, S. ); Wignall, G.D. . Solid State Div.); Hammouda, B. . Center for High Resolution Neutron Scattering)

    1994-11-07

    The structure of ultrathin cellulose acetate membranes, known as active layer membranes, has been investigated using small-angle neutron scattering. These membranes are known to have structural and functional similarity to the surface or skin layer in commercial reverse-osmosis (RO) membranes and hence are useful model systems for understanding the structure of the RO membrane skin layer. Active layer membranes were studied after swelling them with either D[sub 2]O or CD[sub 3]OD. The results in both cases clearly indicated the presence of very small (10--20 [angstrom]) porous structures in the membrane. The presence of such pores has been a subject of long-standing controversy in this area. The data were analyzed using a modified Debye-Bueche analysis and the resultant membrane structure was seen to agree well with structural information from electron microscopic studies. Finally, a possible explanation for the differences in scattering observed between the D[sub 2]O swollen membranes and the CD[sub 3]OD swollen membranes has been presented.

  9. Immobilization of cholesterol oxidase on cellulose acetate membrane for free cholesterol biosensor development.

    PubMed

    Wang, Shenqi; Li, Shipu; Yu, Yaoting

    2004-01-01

    This article describes the immobilization of cholesterol oxidase on a cellulose acetate (CA) membrane activated by Sodium periodate, ethylenediamine, and glutaraldehyde etc. The properties of the immobilized enzyme membrane were investigated. The factors affecting the activity of immobilized enzyme such as the concentration of glutaraldehyde, the concentration of enzyme used during immobilization, temperature, pH, and immobilizing time etc. were also studied. The immobilized COD membrane has been used to construct fibre-optic fluorescent biosensor.

  10. Studies on gas transport through dry cellulose acetate membranes prepared by solvent exchange technique

    SciTech Connect

    Lui, A.; Talbot, F.D.F.; Sourirajan, S.; Fouda, A.; Matsuura, T.

    1988-10-01

    The mechanism of gas transport through pores on the surface of dry cellulose acetate membranes under pressure was identified for membranes prepared by the solvent exchange technique using pure gas permeation rate data. The pure gases were helium, methane and carbon dioxide. The variables involved in the membrane preparation variables involved in the membrane preparation are the shrinkage temperature, the first solvent, the second solvent and the combinations thereof. Different conditions of membrane preparation produce different pore sizes. Depending on this pore size, one of the following mechanisms becomes dominant: Knudsen, surface and size exclusion.

  11. Integration of nanoporous membranes for sample filtration/preconcentration in microchip electrophoresis.

    PubMed

    Long, Zhicheng; Liu, Dayu; Ye, Nannan; Qin, Jianhua; Lin, Bingcheng

    2006-12-01

    Microfluidic devices integrating membrane-based sample preparation with electrophoretic separation are demonstrated. These multilayer devices consist of 10 nm pore diameter membranes sandwiched between two layers of PDMS substrates with embedded microchannels. Because of the membrane isolation, material exchange between two fluidic layers can be precisely controlled by applied voltages. More importantly, since only small molecules can pass through the nanopores, the integrated membrane can serve as a filter or a concentrator prior to microchip electrophoresis under different design and operation modes. As a filter, they can be used for separation and selective injection of small analytes from sample matrix. This has been effectively applied in rapid determination of reduced glutathione in human plasma and red blood cells without any off-chip deproteinization procedure. Alternatively, in the concentrator mode, they can be used for online purification and preconcentration of macromolecules, which was illustrated by removing primers and preconcentrating the product DNA from a PCR product mixture.

  12. Performance of cellulose acetate butyrate membranes in hyperfiltration of sodium chloride and urea feed solution

    NASA Technical Reports Server (NTRS)

    Wydeven, T.; Leban, M.

    1973-01-01

    Cellulose acetate butyrate (CAB) membranes are shown to give high salt and urea rejection with water flux of about 3 gallons/sq ft per day at 600 psig. Membranes prepared from a formulation containing glyoxal show a significant increase in flux and decrease in salt and urea rejection with drying time. Zero drying time gives maximum urea and salt rejection and is therefore most suitable for hyperfiltration of sodium chloride and urea feed solution.

  13. CHARACTERISTICS OF POROUS CELLULOSE ACETATE MEMBRANES FOR THE SEPARATION OF SOME INORGANIC SALTS IN AQUEOUS SOLUTION,

    DTIC Science & Technology

    Experimental results are presented to illustrate the effect of operating variables on the separation and flow characteristics of porous cellulose ... acetate membranes. The results are discussed from the point of view of the preferential sorption and capillary flow mechanism, together with the concept

  14. Tailoring the properties of asymmetric cellulose acetate membranes by gas plasma etching.

    PubMed

    Olde Riekerink, M B; Engbers, G H M; Wessling, M; Feijen, J

    2002-01-15

    Cellulose triacetate (CTA) ultrafilters and cellulose acetate blend (CAB) desalination membranes were treated with a radiofrequency gas plasma (tetrafluoromethane (CF(4)) or carbon dioxide (CO(2)), 47-49 W, 0.04-0.08 mbar). Treatment times were varied between 15 s and 120 min. The plasma-treated top layer of the membranes was characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and contact angle measurements to obtain information about surface structure, chemistry, and wettability, respectively. The membrane properties (e.g., permeability, selectivity, fouling) were studied by waterflux measurements, molecular weight cutoff measurements, and fouling experiments with bovine serum albumin. CO(2) plasma treatment resulted in gradual etching of the membrane's dense top layer. Permeation and selectivity changed significantly for treatment times of 0-15 min for CTA and 5-60 min for CAB membranes. Moreover, CTA membranes were hydrophilized during CO(2) plasma treatment whereas CF(4) plasma treatment led to hydrophobic surfaces due to strong fluorination of the top layer. This study shows that gas plasma etching can tailor the properties of asymmetric cellulose acetate membranes by simultaneously modifying the chemistry and structure of the top layer. The low fouling properties of CTA membranes were thereby largely maintained.

  15. Self-sterilized composite membranes of cellulose acetate/polyethylene glycol for water desalination.

    PubMed

    Ahmad, Adnan; Jamshed, Fahad; Riaz, Tabinda; Gul, Sabad-E-; Waheed, Sidra; Sabir, Aneela; AlAnezi, Adnan Alhathal; Adrees, Muhammad; Jamil, Tahir

    2016-09-20

    Cellulose acetate/Polyethylene glycol-600 composite membranes were fabricated by two step phase inversion procedure and modified by in-situ reduction of silver nitrate. FTIR spectra demonstrated the existence of functional groups for bonding of silver with oxygen at 370cm(-1), 535cm(-1). The XRD diffractogram indicates characteristic peaks at 2θ values of 38.10°, 44.30°, 64.40°, and 77.30° which confirm the successful incorporation of silver within matrix of composite membranes. The morphology of composite membranes with appearances of spongy voids was exemplified from the scanning electron microscope. The atomic force microscopy was used to determine the increase in the surface roughness of the membranes. The increase in hydrophilicity, measured through contact angle, is rendered to the embedment of silver. The modification of membranes increased the flux from 0.80 to 0.95L/hr.m(2). The resulting membranes have outstanding ability to fight against gram negative Escherichia Coli and Bacillus Sabtilus. The novel cellulose acetate/polyethylene glycol membranes customized with silver have paved the path for evolution of axenic membranes.

  16. 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.

  17. Electrospinning of silver nanoparticles loaded highly porous cellulose acetate nanofibrous membrane for treatment of dye wastewater

    NASA Astrophysics Data System (ADS)

    Wang, Ke; Ma, Qian; Wang, Shu-Dong; Liu, Hua; Zhang, Sheng-Zhong; Bao, Wei; Zhang, Ke-Qin; Ling, Liang-Zhong

    2016-01-01

    In this paper, silver nanoparticles (NPs) were reduced form silver nitrate. Morphology and distribution of the synthesized silver NPs were characterized. In order to obtain cellulose acetate (CA), nanofibrous membrane with high effective adsorption performance to carry silver NPs for treatment of dye wastewater, different solvent systems were used to fabricate CA nanofibrous membranes with different morphologies and porous structures via electrospinning. Morphologies and structures of the obtained CA nanofibrous membranes were compared by scanning electron microscopy (SEM), which showed that CA nanofibrous membrane obtained from acetone/dichloromethane (1/2, v/v) was with the highly porous structure. SEM, energy-dispersive spectrometry and Fourier transform infrared spectrometry showed that the silver NPs were effectively incorporated in the CA nanofibrous membrane and the addition of silver NPs did not damage the porous structure of the CA nanofibrous membrane. Adsorption of dye solution (rhodamine B aqueous solution) revealed that the highly porous CA nanofibrous membrane exhibited effective adsorption performance and the addition of silver NPs did not affect the adsorption of the dye. Antibacterial property of the CA nanofibrous membrane showed that the silver-loaded highly porous CA nanofibrous membrane had remarkable antibacterial property when compared to the CA nanofibrous membrane without silver NPs. The silver-loaded highly porous CA nanofibrous membrane could be considered as an ideal candidate for treatment of the dye wastewater.

  18. Effect of coagulant bath on the gas permeation properties of cellulose acetate asymmetric membrane

    NASA Astrophysics Data System (ADS)

    Mohamed, F.; Hasbullah, H.; Jami'an, W. N. R.; Salleh, W. N. H. W.; Ibrahim, N.; Ali, R. R.

    2016-06-01

    Membrane based gas separation process technology has been recognized as one of the most efficient and advanced unit operation for gas separation. One of the problems in membrane gas separation is membrane performance. This paper explores the application of cellulose acetate (CA) membrane for natural gas purification and separation by improving its permeability and selectivity. The main interest in this research is to study the effect of quench medium on the gas separation performance towards its physical characteristics and gas separation performance of CA membrane. Cellulose acetate polymer was dissolved in n- methyl-2-pyrrolidone solvent and casted onto a glass plate using a pneumatically controlled casting system with fixed shear rate and solvent evaporation times. The parameter varied was the non-solvent used as quench medium during membrane post treatment that were methanol and n-hexane. The different quench media as post treatment affected the O2 and N2 gas permeation and O2/N2 selectivity as well as the tensile strength of the flat sheet asymmetric membrane. Combination of methanol and n-hexane as quench media gave the best result than the other steps. This solvent exchange step influenced the morphology by producing thin skin layer and thus gives better gas separation performance than other steps

  19. Study of polydimethylsiloxane/aromatic polyamide laminated membranes for separation of acetic acid/water mixtures by pervaporation process

    SciTech Connect

    Deng, S.; Sourirajan, S.; Matsuura, T. )

    1994-06-01

    Separation of acetic acid/water mixtures by pervaporation was attempted over a range of compositions using polydimethylsiloxane (PDMS), aromatic polyamide (PA), and laminated polydimethylsiloxane-aromatic polyamide membranes. PDMS membranes are hydrophobic and acetic acid selective, whereas PA membranes are hydrophilic and water selective. When PDMS and PA membranes were laminated, with PDMS on the top side and in contact with the feed, water selectivity of the bottom PA membrane was intensified. On the other hand, when the PA membrane was on the top side and in contact with the feed, the selectivity was lowered. 10 refs., 4 figs.

  20. Study of ABO blood types by combining membrane electrophoresis with surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Lin, Juqiang; Huang, Zufang; Sun, Liqing; Shao, Yonghong; Lu, Peng; Shi, Wei; Lin, Jinyong; Chen, Rong

    2012-12-01

    The molecular characterization of ABO blood types, which is clinically significant in blood transfusion, has clinical and anthropological importance. Polymerase chain reaction sequence-based typing (PCR-SBT) is one of the most commonly used methods for the analysis of genetic bases of ABO blood types. However, such methods as PCR-SBT are time-consuming and are high in demand of equipments and manipulative skill. Here we showed that membrane electrophoresis based SERS method employed for studying the molecular bases of ABO blood types can provide rapidand easy-operation with high sensitivity and specificity. The plasma proteins were firstly purified by membrane electrophoresis and then mixed with silver nanoparticles to perform SERS detection. We use this method to classify different blood types, including blood type A (n=13), blood type B (n=9) and blood type O (n=10). Combination of principal component analysis (PCA) and liner discriminant analysis (LDA) was then performed on the SERS spectra of purified albumin, showing good classification results among different blood types. Our experimental outcomes represent a critical step towards the rapid, convenient and accurate identification of ABO blood types.

  1. A high-definition native polyacrylamide gel electrophoresis system for the analysis of membrane complexes.

    PubMed

    Ladig, Roman; Sommer, Maik S; Hahn, Alexander; Leisegang, Matthias S; Papasotiriou, Dimitrios G; Ibrahim, Mohamed; Elkehal, Rajae; Karas, Michael; Zickermann, Volker; Gutensohn, Michael; Brandt, Ulrich; Klösgen, Ralf Bernd; Schleiff, Enrico

    2011-07-01

    Native polyacrylamide gel electrophoresis (PAGE) is an important technique for the analysis of membrane protein complexes. A major breakthrough was the development of blue native (BN-) and high resolution clear native (hrCN-) PAGE techniques. Although these techniques are very powerful, they could not be applied to all systems with the same resolution. We have developed an alternative protocol for the analysis of membrane protein complexes of plant chloroplasts and cyanobacteria, which we termed histidine- and deoxycholate-based native (HDN-) PAGE. We compared the capacity of HDN-, BN- and hrCN-PAGE to resolve the well-studied respiratory chain complexes in mitochondria of bovine heart muscle and Yarrowia lipolytica, as well as thylakoid localized complexes of Medicago sativa, Pisum sativum and Anabaena sp. PCC7120. Moreover, we determined the assembly/composition of the Anabaena sp. PCC7120 thylakoids and envelope membranes by HDN-PAGE. The analysis of isolated chloroplast envelope complexes by HDN-PAGE permitted us to resolve complexes such as the translocon of the outer envelope migrating at approximately 700 kDa or of the inner envelope of about 230 and 400 kDa with high resolution. By immunodecoration and mass spectrometry of these complexes we present new insights into the assembly/composition of these translocation machineries. The HDN-PAGE technique thus provides an important tool for future analyses of membrane complexes such as protein translocons.

  2. Fabrication and performance of PET mesh enhanced cellulose acetate membranes for forward osmosis.

    PubMed

    Li, Guoliang; Wang, Jun; Hou, Deyin; Bai, Yu; Liu, Huijuan

    2016-07-01

    Polyethylene terephthalate mesh (PET) enhanced cellulose acetate membranes were fabricated via a phase inversion process. The membrane fabrication parameters that may affect the membrane performance were systematically evaluated including the concentration and temperature of the casting polymer solution and the temperature and time of the evaporation, coagulation and annealing processes. The water permeability and reverse salt flux were measured in forward osmosis (FO) mode for determination of the optimal membrane fabrication conditions. The optimal FO membrane shows a typical asymmetric sandwich structure with a mean thickness of about 148.2μm. The performance of the optimal FO membrane was tested using 0.2mol/L NaCl as the feed solution and 1.5mol/L glucose as the draw solution. The membrane displayed a water flux of 3.47L/(m(2)·hr) and salt rejection of 95.48% in FO mode. While in pressure retarded osmosis (PRO) mode, the water flux was 4.74L/(m(2)·hr) and salt rejection 96.03%. The high ratio of water flux in FO mode to that in PRO mode indicates that the fabricated membrane has a lower degree of internal concentration polarization than comparable membranes.

  3. Alginate fouling reduction of functionalized carbon nanotube blended cellulose acetate membrane in forward osmosis.

    PubMed

    Choi, Hyeon-Gyu; Son, Moon; Yoon, SangHyeon; Celik, Evrim; Kang, Seoktae; Park, Hosik; Park, Chul Hwi; Choi, Heechul

    2015-10-01

    Functionalized multi-walled carbon nanotube blended cellulose acetate (fCNT-CA) membranes were synthesized for forward osmosis (FO) through phase inversion. The membranes were characterized through SEM, FTIR, and water contact angle measurement. AFM was utilized to investigate alginate fouling mechanism on the membrane. It reveals that the fCNT contributes to advance alginate fouling resistance in FO (57% less normalized water flux decline for 1% fCNT-CA membrane was observed than that for bare CA membrane), due to enhanced electrostatic repulsion between the membrane and the alginate foulant. Furthermore, it was found that the fCNT-CA membranes became more hydrophilic due to carboxylic groups in functionalized carbon nanotube, resulting in approximately 50% higher water-permeated flux than bare CA membrane. This study presents not only the fabrication of fCNT-CA membrane and its application to FO, but also the quantification of the beneficial role of fCNT with respect to alginate fouling in FO.

  4. Effect of evaporation time on cellulose acetate membrane for gas separation

    NASA Astrophysics Data System (ADS)

    Jami'an, W. N. R.; Hasbullah, H.; Mohamed, F.; Yusof, N.; Ibrahim, N.; Ali, R. R.

    2016-06-01

    Throughout this decades, membrane technology has been the desirable option among the others gas separation technologies. However, few issues have been raised regarding the membrane gas separation application including the trade-off between its permeability and selectivity and also its effects towards environment. Therefore, for this research, a biopolymer membrane for gas separation application will be developed with reasonably high on both permeability and selectivity. The main objective of this research is to study the effect of solvent evaporation time on the flat sheet asymmetric membrane morphology and gas separation performance. The membranes were produced by a simple dry/wet phase inversion technique using a pneumatically controlled casting system. The dope solution for the membrane casting was prepared by dissolving the cellulose acetate (CA) polymer in N-Methyl-2-pyrrolidone (NMP) and the solvent evaporation time was varied. Permeability and selectivity of the membrane was performed by using pure gases of carbon dioxide, CO2 and methane, CH4. The increase in solvent evaporation time had improved the membrane morphologies as the porosity of the membrane surface decrease and formation of a more mature skin layer. The gas permeation tests determined that increasing in solvent evaporation time had increased the selectivity of CO2/CH4 but reduce the permeability of both gases

  5. Separation of macromolecular proteins and removal of humic acid by cellulose acetate modified UF membranes.

    PubMed

    Kanagaraj, P; Nagendran, A; Rana, D; Matsuura, T

    2016-08-01

    Surface modifying macromolecules (SMMs) were synthesized with various polyurethane pre polymers end-capped with different groups and blended into the casting solution of cellulose acetate (CA) to prepare surface modified ultra-filtration (UF) membranes for water filtration applications. The surface modification of the CA membranes was confirmed by the FTIR and static contact angle (SCA) measurements. The membranes so prepared had the typical characteristics of UF membranes as confirmed by scanning electron microscopy (SEM). Membrane properties were studied in terms of membrane compaction, percentage water content (%WC), pure water flux (PWF), membrane hydraulic resistance (Rm), molecular weight cut-off (MWCO), average pore size and porosity. The result showed that PWF, %WC, MWCO and pore size increased whereas the Rm decreased by the addition of SMMs. The significant effect of SMMs on the fouling by humic acid (HA) was also observed. It was found that the cSMM-3 membrane, in which SMM was synthesized with diethylene glycol (DEG) and hydroxyl benzene sulfonate (HBS) was blended, had the highest flux recovery ratio FRR (84.6%), as well as the lowest irreversible fouling (15.4%), confirming their improved antifouling properties. Thus, the SMM modified CA membranes had proven, to play an important role in the water treatment by UF.

  6. Cellulose Acetate 398-10 Asymmetric Membrane Capsules for Osmotically Regulated Delivery of Acyclovir.

    PubMed

    Sonkar, Alka; Kumar, Anil; Pathak, Kamla

    2016-01-01

    The study was aimed at developing cellulose acetate asymmetric membrane capsules (AMCs) of acyclovir for its controlled delivery at the absorption site. The AMCs were prepared by phase inversion technique using wet process. A 2(3) full factorial design assessed the effect of independent variables (level(s) of polymer, pore former, and osmogen) on the cumulative drug release from AMCs. The buoyant optimized formulation F7 (low level of cellulose acetate; high levels of both glycerol and sodium lauryl sulphate) displayed maximum drug release of 97.88 ± 0.77% in 8 h that was independent of variation in agitational intensity and intentional defect on the cellulose acetate AMC. The in vitro data best fitted zero-order kinetics (r (2) = 0.9898). SEM micrograph of the transverse section confirmed the asymmetric nature of the cellulose acetate capsular membrane. Statistical analysis by Design Expert software indicated no interaction between the independent variables confirming the efficiency of the design in estimating the effects of variables on drug release. The optimized formulation F7 (desirability = 0.871) displayed sustenance of drug release over the drug packed in AMC in pure state proving the superiority of osmotically active formulation. Conclusively the AMCs have potential for controlled release of acyclovir at its absorption site.

  7. Removal of acetic acid from simulated hemicellulosic hydrolysates by emulsion liquid membrane with organophosphorus extractants.

    PubMed

    Lee, Sang Cheol

    2015-09-01

    Selective removal of acetic acid from simulated hemicellulosic hydrolysates containing xylose and sulfuric acid was attempted in a batch emulsion liquid membrane (ELM) system with organophosphorus extractants. Various experimental variables were used to develop a more energy-efficient ELM process. Total operation time of an ELM run with a very small quantity of trioctylphosphine oxide as the extractant was reduced to about a third of those required to attain almost the same extraction efficiency as obtained in previous ELM works without any extractant. Under specific conditions, acetic acid was selectively separated with a high degree of extraction and insignificant loss of xylose, and its purity and enrichment ratio in the stripping phase were higher than 92% and 6, respectively. Also, reused organic membrane solutions exhibited the extraction efficiency as high as fresh organic solutions did. These results showed that the current ELM process would be quite practical.

  8. Microemulsion liquid membranes. I. Application to acetic acid removal from water

    SciTech Connect

    Wiencek, J.M.; Qutubuddin, S. )

    1992-08-01

    A separation technique utilizing nonionic microemulsions as emulsion liquid membranes has been successfully applied to the removal of acetic acid from an aqueous feed phase. The surfactant systems were carefully characterized in order to assure that they were truly microemulsions. The effects of mixing intensity, feed concentration, treat ratio, and microemulsion viscosity on the separation kinetics were investigated. The microemulsions did not typically display leakage and had negligible swell over 5-minute duration. The reversible phase behavior of the microemulsion was utilized to demulsify the liquid membrane phase and recover the acetate ion via a temperature change of approximately 40 C. Material balances closed to within 10% and rates of separation were faster than the sampling rates when the microemulsion was fully dispersed in the aqueous feed phase.

  9. Comparison of diffusion by anionic surfactants through cellulose acetate and collagen membranes.

    PubMed

    García Ramón, M T; Ribosa, I; Leal, J S; Parra, J L

    1989-06-01

    Synopsis From a dermatological point of view, it is important to know what is the irritation potential of surfactants on human skin. Recent research trends have been oriented towards the establishment of new 'in vitro' techniques that will avoid animal experimentation. In this paper, some results on the rate of diffusion of different anionic surfactants through both cellulose acetate and collagen membranes are described. A correlation between results of diffusion through the protein membrane and results published on the same surfactants and their irritation potential during 'in vivo' experiments appears possible.

  10. Adsorption of N-alkylpyridinium chlorides from water and salt solutions on cellulose acetate ultrafiltration membranes

    SciTech Connect

    Klimenko, N.A.; Yaroshenko, N.A.; Kondratova, T.B.

    1988-09-01

    A study has been made of the adsorption of three homologues in the N-alkylpyridinium chloride series from water and salt solutions, over a wide range of concentrations, on cellulose acetate ultrafiltration membranes, Grades UAM-500 and UAM-150. When adsorption takes place from true solutions, the membrane surface is hydrophobized. In the region of micellar solutions, nonassociated molecules and micelles are adsorbed in the mesopores and supermicropores, forming a mosaic adsorption layer. The thickness of the modifying layer depends on the length of the hydrophobic radical and on the composition of the system.

  11. Synergistic Effect of Functionalized Nanokaolin Decorated MWCNTs on the Performance of Cellulose Acetate (CA) Membranes Spectacular.

    PubMed

    Afzal, Amina; Rafique, Muhammad Shahid; Iqbal, Nadeem; Qaiser, Asif Ali; Anwar, Abdul Waheed; Iqbal, Sadia Sagar

    2016-04-21

    In order to enhance salt rejection level and high pressure mechanical integrity, functionalized nanokaolin decorated multiwall carbon nanotubes (FNKM, 0-5 wt % loading) were incorporated into a cellulose acetate (CA) matrix using high temperature solution mixing methodology. Scanning electron microscopy (SEM), X-ray diffraction technique (XRD), thermo-gravimetric analyzer (TGA) and Fourier transform infrared spectrometer (FTIR) were used to characterize the prepared membranes. The obtained results revealed that with increasing FNKM concentration in the host polymeric matrix, composite membrane's structural, functional, thermal, water permeation/flux and salt rejection characteristics were also modified accordingly. Percent enhancement in salt rejection was increased around threefold by adding 5 wt % FNKM in CA.

  12. Simultaneous determination of creatinine and acetate by capillary electrophoresis with contactless conductivity detector as a feasible approach for urinary tract infection diagnosis.

    PubMed

    Grochocki, Wojciech; Markuszewski, Michał J; Quirino, Joselito P

    2017-04-15

    Urinary tract infection (UTI) is one of the most common bacterial infection in human but its diagnosis is difficult. Metabolomic studies with nuclear magnetic resonance of urine have shown that acetic acid/creatinine ratio may be used for early UTI diagnosis. Here, a method for simultaneous determination of acetate and creatinine by capillary zone electrophoresis with contactless conductivity detector was developed for the first time. The separation was with 40mM MES and 20mM l-histidine as a background solution. The total time of a single run, including capillary conditioning, was less than 12min. The method was successfully demonstrated for analysis of actual and fortified human urine samples after methanol dilution. Analytical figures of merit such as linearity, LOQ, and repeatability (intraday and interday) were studied.

  13. The wettability of a cellulose acetate membrane in the presence of bovine serum albumin

    NASA Astrophysics Data System (ADS)

    Białopiotrowicz, Tomasz; Jańczuk, Bronisław

    2002-11-01

    The measurements of the contact angle for water (W), glycerol (G), formamide (F), ethylene glycol (E) and diiodomethane (D) on a bare cellulose acetate membrane and covered by adsorptive bovine serum albumin (BSA) films were made. The adsorption was performed from solutions in concentration range 0-100 mg/ml. An influence of the membrane porosity on an apparent contact angle was discussed and Cassie and Baxter equation was used for that purpose. It was suggested that some liquids could penetrate in to membrane pores reducing its apparent porosity. To explain such behaviour, the spreading coefficient and the work of adhesion was calculated for the studied liquids. Components and parameters of the surface free energy of a bare cellulose acetate membrane and covered by an adsorptive BSA film were determined for W-G-D, W-F-D and G-F-D three-liquid systems and they were similar for these systems. However, for the hydrated BSA layer those components and parameters for the systems W-G-D, W-F-D were different than those for the system G-F-D. It was stated that after BSA adsorption on that membrane percentage of empty pores decreased, reducing their number almost to 0, at the highest BSA concentrations.

  14. 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.

  15. High resolution clear native electrophoresis is a good alternative to blue native electrophoresis for the characterization of the Escherichia coli membrane complexes.

    PubMed

    Diéguez-Casal, Ernesto; Freixeiro, Paula; Costoya, Liliana; Criado, M Teresa; Ferreirós, Carlos; Sánchez, Sandra

    2014-07-01

    Blue native electrophoresis (BNE) has become the most popular method for the global analysis of membrane protein complexes. Although it has been shown to be very useful for that purpose, it can produce the dissociation of complexes with weak interactions and, due to the use of Coomassie Brilliant Blue, does not allow the subsequent application of fluorimetric and/or enzymatic techniques. Recently, we have successfully used the high resolution clear native electrophoresis (hrCNE) for the analysis of Neisseria meningitidis outer membrane porin complexes. The aim of this study was to determine the composition of the complexome of the Escherichia coli envelope by using hrCNE and to compare our results with those previously obtained using BNE. The bidimensional electrophoresis approaches used, hrCN/hrCNE and hrCN/SDS-PAGE, coupled to mass spectrometry allowed a detailed analysis of the complexome of E. coli membranes. For the first time, the three subunits of the formate dehydrogenase FDH-O were identified forming a single complex and hrCNE also allowed the identification of both the HflK and HflC proteins as components of the HflA complex. This technique also allowed us to suggest a relationship between OmpF and DLDH and, although OmpA is considered to be monomeric in vivo, we found this protein structured as homodimers. Thus hrCNE provides a good tool for future analyses of bacterial membrane proteins and complexes and is an important alternative to the commonly used BNE.

  16. Microfluidic free-flow zone electrophoresis and isotachophoresis using carbon black nano-composite PDMS sidewall membranes.

    PubMed

    Fu, Xiaotong; Mavrogiannis, Nicholas; Ibo, Markela; Crivellari, Francesca; Gagnon, Zachary R

    2017-01-01

    We present a new type of free-flow electrophoresis (FFE) device for performing on-chip microfluidic isotachophoresis and zone electrophoresis. FFE is performed using metal gallium electrodes, which are isolated from a main microfluidic flow channel using thin micron-scale polydimethylsiloxane/carbon black (PDMS/CB) composite membranes integrated directly into the sidewalls of the microfluidic channel. The thin membrane allows for field penetration and effective electrophoresis, but serves to prevent bubble generation at the electrodes from electrolysis. We experimentally demonstrate the ability to use this platform to perform on-chip free-flow electrophoretic separation and isotachophoretic concentration. Due to the small size and simple fabrication procedure, this PDMS/CB platform could be used as a part of an on-chip upstream sample preparation toolkit for portable microfluidic diagnostic applications.

  17. FTIR, XRD and DSC studies of nanochitosan, cellulose acetate and polyethylene glycol blend ultrafiltration membranes.

    PubMed

    Vinodhini, P Angelin; K, Sangeetha; Thandapani, Gomathi; P N, Sudha; Jayachandran, Venkatesan; Sukumaran, Anil

    2017-03-29

    In the present work, a series of novel nanochitosan/cellulose acetate/polyethylene glycol (NCS/CA/PEG) blend flat sheet membranes were fabricated in different ratios (1:1:1, 1:1:2, 2:1:1, 2:1:2, 1:2:1, 2:2:1) in a polar solvent of N,N'-dimethylformamide (DMF) using the most popular phase inversion method. Nanochitosan was prepared by the ionotropic gelation method and its average particle size has been analyzed using Dynamic Light Scattering (DLS) method. The effect of blending of the three polymers was investigated using FTIR and XRD studies. FTIR results confirmed the formation of well-blended membranes and the XRD analysis revealed enhanced amorphous nature of the membrane ratio 2:1:2. DSC study was conducted to find out the thermal behavior of the blend membranes and the results clearly indicated good thermal stability and single glass transition temperature (Tg) of all the prepared membranes. Asymmetric nature and rough surface morphology was confirmed using SEM analysis. From the results it was evident that the blending of the polymers with higher concentration of nanochitosan can alter the nature of the resulting membranes to a greater extent and thus amorphous membranes were obtained with good miscibility and compatibility.

  18. Dehydration of water/pyridine mixtures by pervaporation using cellulose acetate/ polyacrylonitrile blend membrane.

    PubMed

    Lv, J H; Xiao, G M

    2011-01-01

    Cellulose acetate/ polyacrylonitrile (CA/PAN) membranes were prepared and used to separate pyridine / water mixtures by pervaporation. The membranes were characterized through SEM. The effects of feed concentration, operation temperature and downstream pressure on the separation performance were evaluated. Experimental results indicated the increase of operation temperature could raise the permeation flux and the separation factor, while increasing feed concentration and downstream pressure would raise the separation factor and decrease the permeation flux. Under the conditions that pyridine solution was 99 wt.%, operation temperature was 323 K and downstream pressure was 20 mmHg, the CA/PAN blend membrane showed its best separation performance that the permeation flux was 56.g.m-2 h-1 and the separation factor was 182.

  19. Morphological analysis of Polyethersulfone/polyvinyl Acetate blend membrane synthesized at various polymer concentrations

    NASA Astrophysics Data System (ADS)

    Hadi, S. H. A. A.; Mannan, H. A.; Mukhtar, H.; Shaharun, M. S.; Murugesan, T.

    2016-06-01

    This paper reports the effect of varying polymer concentration i.e. solvent/polymer ratio on the morphology and gas transport behaviour of polyethersulfone/polyvinyl acetate blend membrane. The solvent used was dimethylformamide, while the manipulated variable was polymer concentration. The concentrations were varied from 75-90 weight % solvent. A homogeneous surface with dense cross-section structure membranes were successfully developed as deduced from FESEM images. The permeability of CO2 and CH4 gases increased with increasing polymer concentration and an improved CO2/CH4 selectivity was observed. These observation made from the characterization justified the applicability of the blend to be synthesized as membrane for gas separation.

  20. Electrospun cellulose acetate composites containing supported metal nanoparticles for antifungal membranes.

    PubMed

    Quirós, Jennifer; Gonzalo, Soledad; Jalvo, Blanca; Boltes, Karina; Perdigón-Melón, José Antonio; Rosal, Roberto

    2016-09-01

    Electrospun cellulose acetate composites containing silver and copper nanoparticles supported in sepiolite and mesoporous silica were prepared and tested as fungistatic membranes against the fungus Aspergillus niger. The nanoparticles were in the 3-50nm range for sepiolite supported materials and limited by the size of mesopores (5-8nm) in the case of mesoporous silica. Sepiolite and silica were well dispersed within the fibers, with larger aggregates in the micrometer range, and allowed a controlled release of metals to create a fungistatic environment. The effect was assessed using digital image analysis to evaluate fungal growth rate and fluorescence readings using a viability stain. The results showed that silver and copper nanomaterials significantly impaired the growth of fungi when the spores were incubated either in direct contact with particles or included in cellulose acetate composite membranes. The fungistatic effect took place on germinating spores before hyphae growth conidiophore formation. After 24h the cultures were separated from fungistatic materials and showed growth impairment only due to the prior exposure. Growth reduction was important for all the particles and membranes with respect to non-exposed controls. The effect of copper and silver loaded materials was not significantly different from each other with average reductions around 70% for bare particles and 50% for membranes. Copper on sepiolite was particularly efficient with a decrease of metabolic activity of up to 80% with respect to controls. Copper materials induced rapid maturation and conidiation with fungi splitting in sets of subcolonies. Metal-loaded nanomaterials acted as reservoirs for the controlled release of metals. The amount of silver or copper released daily by composite membranes represented roughly 1% of their total load of metals. Supported nanomaterials encapsulated in nanofibers allow formulating active membranes with high antifungal performance at the same time

  1. Adsorptive removal of phenolic compounds using cellulose acetate phthalate-alumina nanoparticle mixed matrix membrane.

    PubMed

    Mukherjee, Raka; De, Sirshendu

    2014-01-30

    Mixed matrix membranes (MMMs) were prepared using alumina nanoparticles and cellulose acetate phthalate (CAP) by varying concentration of nanoparticles in the range of 10 to 25wt%. The membranes were characterized by scanning electron micrograph, porosity, permeability, molecular weight cut off, contact angle, surface zeta potential, mechanical strength. Addition of nanoparticles increased the porosity, permeability of the membrane up to 20wt% of alumina. pH at point of zero charge of the membrane was 5.4. Zeta potential of the membrane became more negative up to 20wt% of nanoparticles. Adsorption of phenolic derivatives, catechol, paranitrophenol, phenol, orthochloro phenol, metanitrophenol, by MMMs were investigated. Variation of rejection and permeate flux profiles were studied for different solutes as a function of various operating conditions, namely, solution pH, solute concentration in feed and transmembrane pressure drop. Difference in rejection of phenolic derivatives is consequence of interplay of surface charge and adsorption by alumina. Adsorption isotherm was fitted for different solutes and effects of pH were investigated. Catechol showed the maximum rejection 91% at solution pH 9. Addition of electrolyte reduced the rejection of solutes. Transmembrane pressure drop has insignificant effects on solute rejection. Competitive adsorption reduced the rejection of individual solute.

  2. Pervaporation of water and ethanol using a cellulose acetate butyrate membrane

    SciTech Connect

    Wu, W.S.; Lau, W.W.Y.; Rangaiah, G.P.; Sourirajan, S. . Dept. of Chemical Engineering)

    1993-10-15

    Okada and Matsuura's transport equations for pervaporation give rise to three fundamental parameters, namely, interfacial saturation vapor pressure P*, liquid transport parameter A/[delta], and vapor transport parameter B/[delta]. The effects of the chemical nature of the membrane material and the upstream operating pressures of 101.3 and 303.9 kPa on the above parameters were investigated from the pervaporation data at laboratory temperature (24 C) for water and ethanol using a cellulose acetate butyrate membrane. The results show that the P. values are essentially unaffected by the upstream pressure, and that they are generally higher than the literature values of saturation vapor pressure at 24 C. Further, the values for A/[delta] and B/[delta] tend to increase with increased upstream pressure for both systems studied. These results are discussed.

  3. Tunable membranes for free-flow zone electrophoresis in PDMS microchip using guided self-assembly of silica microbeads.

    PubMed

    Song, Yong-Ak; Wu, Lidan; Tannenbaum, Steven R; Wishnok, John S; Han, Jongyoon

    2013-12-17

    In this paper, we evaluate the strategy of using self-assembled microbeads to build a robust and tunable membrane for free-flow zone electrophoresis in a PDMS microfluidic chip. To fabricate a porous membrane as a salt bridge for free-flow zone electrophoresis, we used silica or polystyrene microbeads between 3-6 μm in diameter and packed them inside a microchannel. After complete evaporation, we infiltrated the porous microbead structure with a positively or negatively charged hydrogel to modify its surface charge polarity. Using this device, we demonstrated binary sorting (separation of positive and negative species at a given pH) of peptides and dyes in standard buffer systems without using sheath flows. The sample loss during sorting could be minimized by using ion selectivity of hydrogel-infiltrated microbead membranes. Our fabrication method enables building a robust membrane for pressure-driven free-flow zone electrophoresis with tunable pore size as well as surface charge polarity.

  4. Tuning aluminum spatial distribution in ZSM-5 membranes: a new strategy to fabricate high performance and stable zeolite membranes for dehydration of acetic acid.

    PubMed

    Yang, Jianhua; Li, Liangqing; Li, Wanze; Wang, Jinqu; Chen, Zan; Yin, Dehong; Lu, Jinming; Zhang, Yan; Guo, Hongchen

    2014-12-04

    A novel ZSM-5 membrane with a low Si/Al ratio and homogeneous aluminum spatial distribution was achieved from an organic template-free inorganic gel in the presence of both OH(-) and F(-) ions and the obtained ZSM-5 membrane exhibited excellent selectivity and high flux and stability for dehydration of acetic acid in a wide AcOH content range.

  5. Low cost hydrogen/novel membrane technology for hydrogen separation from synthesis gas, Phase 1. [Polyetherimide, cellulose acetate and ethylcellulose

    SciTech Connect

    Not Available

    1986-01-01

    The goal of this program is to develop polymer membranes useful in the preparation of hydrogen from coal-derived synthesis gas. During this quarter the first experiment were aimed at developing high performance composite membranes for the separation of hydrogen from nitrogen and carbon monoxide. Three polymers have been selected as materials for these membranes: polyetherimide cellulose acetate and ethylcellulose. This quarter the investigators worked on polyetherimide and cellulose acetate membranes. The overall structure of these membranes is shown schematically in Figure 1. As shown, a microporous support membrane is first coated with a high flux intermediate layer then with an ultrathin permselective layer and finally, if necessary, a thin protective high flux layer. 1 fig., 4 tabs.

  6. Synthesis of polymer electrolyte membranes from cellulose acetate/poly(ethylene oxide)/LiClO{sub 4} for lithium ion battery application

    SciTech Connect

    Nurhadini, Arcana, I Made

    2015-09-30

    This study was conducted to determine the effect of cellulose acetate on poly(ethylene oxide)-LiClO{sub 4} membranes as the polymer electrolyte. Cellulose acetate is used as an additive to increase ionic conductivity and mechanical property of polymer electrolyte membranes. The increase the percentage of cellulose acetate in membranes do not directly effect on the ionic conductivity, and the highest ionic conductivity of membranes about 5,7 × 10{sup −4} S/cm was observed in SA/PEO/LiClO{sub 4} membrane with cellulose ratio of 10-25% (w/w). Cellulose acetate in membranes increases mechanical strength of polymer electrolyte membranes. Based on TGA analysis, this polymer electrolyte thermally is stable until 270 °C. The polymer electrolyte membrane prepared by blending the cellulose acetate, poly(ethylene oxide), and lithium chlorate could be potentially used as a polymer electrolyte for lithium ion battery application.

  7. Synthesis of polymer electrolyte membranes from cellulose acetate/poly(ethylene oxide)/LiClO4 for lithium ion battery application

    NASA Astrophysics Data System (ADS)

    Nurhadini, Arcana, I. Made

    2015-09-01

    This study was conducted to determine the effect of cellulose acetate on poly(ethylene oxide)-LiClO4 membranes as the polymer electrolyte. Cellulose acetate is used as an additive to increase ionic conductivity and mechanical property of polymer electrolyte membranes. The increase the percentage of cellulose acetate in membranes do not directly effect on the ionic conductivity, and the highest ionic conductivity of membranes about 5,7 × 10-4 S/cm was observed in SA/PEO/LiClO4 membrane with cellulose ratio of 10-25% (w/w). Cellulose acetate in membranes increases mechanical strength of polymer electrolyte membranes. Based on TGA analysis, this polymer electrolyte thermally is stable until 270 °C. The polymer electrolyte membrane prepared by blending the cellulose acetate, poly(ethylene oxide), and lithium chlorate could be potentially used as a polymer electrolyte for lithium ion battery application.

  8. Plasma membrane proteins Yro2 and Mrh1 are required for acetic acid tolerance in Saccharomyces cerevisiae.

    PubMed

    Takabatake, Akiko; Kawazoe, Nozomi; Izawa, Shingo

    2015-03-01

    Yro2 and its paralogous protein Mrh1 of Saccharomyces cerevisiae have seven predicted transmembrane domains and predominantly localize to the plasma membrane. Their physiological functions and regulation of gene expression have not yet been elucidated in detail. We herein demonstrated that MRH1 was constitutively expressed, whereas the expression of YRO2 was induced by acetic acid stress and entering the stationary phase. Fluorescence microscopic analysis revealed that Mrh1 and Yro2 were distributed as small foci in the plasma membrane under acetic acid stress conditions. The null mutants of these genes (mrh1∆, yro2∆, and mrh1∆yro2∆) showed delayed growth and a decrease in the productivity of ethanol in the presence of acetic acid, indicating that Yro2 and Mrh1 are involved in tolerance to acetic acid stress.

  9. The effects of urease immobilization on the transport characteristics and protein adsorption capacity of cellulose acetate based hemodialysis membranes.

    PubMed

    Mahlicli, Filiz Yasar; Altinkaya, Sacide Alsoy

    2009-10-01

    In this study, cellulose acetate (CA) based hemodialysis membranes were prepared by a dry phase inversion method and the influences of urease immobilization on the clearing performance and protein adsorption capacity of the membranes were investigated. Permeation experiments have shown that modification of CA membranes with urease immobilization not only enhanced the transport rate of urea but also increased the permeation coefficients of uric acid and creatinine by changing the structure of the membrane. Furthermore, the protein adsorption capacity of the CA membranes decreased. On the other hand, the mechanical strength of the modified CA membrane did not change significantly compared with that of the unmodified one. A mathematical model was derived to determine the rate of mass transfer of urea through modified CA membranes. Model predictions along with the experimental data suggest that urease immobilization can be used as an alternative method in preparing CA based hemodialysis membranes with improved transport characteristics and biocompatibility through reduced protein adsorption capacities.

  10. Composite membrane of niobium(V) oxide and cellulose acetate: Preparation and characterization

    SciTech Connect

    Campos, E.A.; Gushikem, Y.

    1997-09-01

    Composite membranes of niobium(V) oxide and cellulose acetate (Cel/Nb{sub 2}O{sub 5}) were prepared with the following Nb{sub 2}O{sub 5} loadings (in wt%): 1.1, 6.1, 9.8, 15.6, and 20.9. The thermal stability of the membranes slightly decreased in relation to the pure membrane on incorporation of the metal oxide into the matrix. Scanning electron microscopy and niobium mapping with an X-ray EDS microprobe showed that the metal oxide particles are homogeneously dispersed in the matrix. The electronic absorption bands indicated that the oxide particle size varies from that of the monomer to those of oligomer species on increased Nb{sub 2}O{sub 5} loading in the matrix. The dispersed oxide possesses mainly Lewis acid character, a clear indication that on increasing the oxide loading in the matrix, the coordination number of the metal is not saturated by formation of the Nb-O-Nb bond. These materials can be useful in ion-exchange process, as supports for enzymes, in catalytic reactions, and in reverse osmosis experiments.

  11. Investigation of the pore structure and morphology of cellulose acetate membranes using small-angle neutron scattering. 2: Ultrafiltration and reverse-osmosis membranes

    SciTech Connect

    Kulkarni, S.; Krause, S. ); Wignall, G.D. . Solid State Div.)

    1994-11-07

    Pore structure in cellulose acetate ultrafiltration (UF) and reverse-osmosis (RO) membranes has been studied using small-angle neutron scattering. Scattering experiments were carried out on dry membranes as well as on membranes swollen with deuterated solvents (D[sub 2]O and CD[sub 3]OD). In addition, the RO membranes were studied both before and after annealing (a process of heating a membrane in a water bath at [approximately]75 C to improve its separation properties). The pore surface in UF membranes was found to be smooth and nonfractal, as evidenced by the fourth power law behavior at high Q. Values of average pore sizes obtained for dry and solvent swollen membranes agree well with pore sizes obtained by other methods. For cellulose acetate RO membranes in their dry state, the unannealed membrane appears to consist of two discrete pore size distributions in the intermediate and high Q region while the annealed membrane contains a much wider distribution of pore sizes. These results give a good account of the changes occurring in the structure of RO membranes as a result of annealing, and agree well with the prediction of other authors.

  12. Membrane transport of hydrocortisone acetate from supersaturated solutions; the role of polymers.

    PubMed

    Raghavan, S L; Kiepfer, B; Davis, A F; Kazarian, S G; Hadgraft, J

    2001-06-19

    Permeation of hydrocortisone acetate (HA) from supersaturated solutions was studied across a model silicone membrane. Supersaturated solutions were prepared using the cosolvent technique with propylene glycol and water (or aqueous polymer solutions) as the cosolvents. In the absence of the polymer, the flux of HA was similar at all degrees of saturation and was not significantly different from the value obtained for a saturated solution. Flux enhancement, as a result of supersaturation, was observed with all the polymers. The flux increased with increasing polymer concentration, reached a maximum and decreased at higher polymer percentages. The amount of polymer required for maximum enhancement differed for each polymer. The decrease of flux at high polymer concentrations is attributed to changes in microviscosity and a marginal increase in solubility. The infrared spectroscopic and differential scanning calorimetry data suggest that HA-polymer interactions occurred through hydrogen bonding thus explaining the proposed mechanism of the anti-nucleant properties of the polymers.

  13. Synergistic Effect of Functionalized Nanokaolin Decorated MWCNTs on the Performance of Cellulose Acetate (CA) Membranes Spectacular

    PubMed Central

    Afzal, Amina; Rafique, Muhammad Shahid; Iqbal, Nadeem; Qaiser, Asif Ali; Anwar, Abdul Waheed; Iqbal, Sadia Sagar

    2016-01-01

    In order to enhance salt rejection level and high pressure mechanical integrity, functionalized nanokaolin decorated multiwall carbon nanotubes (FNKM, 0–5 wt % loading) were incorporated into a cellulose acetate (CA) matrix using high temperature solution mixing methodology. Scanning electron microscopy (SEM), X-ray diffraction technique (XRD), thermo-gravimetric analyzer (TGA) and Fourier transform infrared spectrometer (FTIR) were used to characterize the prepared membranes. The obtained results revealed that with increasing FNKM concentration in the host polymeric matrix, composite membrane’s structural, functional, thermal, water permeation/flux and salt rejection characteristics were also modified accordingly. Percent enhancement in salt rejection was increased around threefold by adding 5 wt % FNKM in CA. PMID:28335207

  14. Serum protein fractionation using supported molecular matrix electrophoresis.

    PubMed

    Dong, Weijie; Matsuno, Yu-ki; Kameyama, Akihiko

    2013-08-01

    Supported molecular matrix electrophoresis (SMME), in which a hydrophilic polymer such as PVA serves as a support within a porous PVDF membrane, was recently developed. This method is similar to cellulose acetate membrane electrophoresis but differs in the compatibility to glycan analysis of the separated bands. In this report, we describe the first instance of the application of SMME to human serum fractionation, and demonstrate the differences with serum fractionation by cellulose acetate membrane electrophoresis. The SMME membrane exhibited almost no EOF during electrophoresis, unlike the cellulose acetate membrane, but afforded comparative results for serum fractionation. The visualization of each fraction was achieved by conventional staining with dye such as Direct Blue-71, and objective quantification was obtained by densitometry after inducing membrane transparency with 1-nonene. Immunostaining was also achieved. Moreover, mass spectrometric analysis of both N-linked and O-linked glycans from the separated bands was demonstrated. Serum fractionation and glycan profiling of each fraction using SMME will enable novel insights into the relationships between various glycosylation profiles and disease states.

  15. Optical, bactericidal and water repellent properties of electrospun nano-composite membranes of cellulose acetate and ZnO.

    PubMed

    Anitha, S; Brabu, B; John Thiruvadigal, D; Gopalakrishnan, C; Natarajan, T S

    2013-09-12

    In this report, ZnO nanoparticles embedded cellulose acetate (CA) fibrous membrane with multifunctional properties have been prepared through electrospinning method. The morphology of the electrospun composite membrane was analyzed by scanning electron microscope (SEM). It was found that the polymer concentration in the solution has a significant effect on the morphology of the fibers. The optical property of the sample was tested using photo luminescence (PL) spectra. There is no significant change in the emission features of cellulose acetate with the addition of ZnO. The anti-bacterial property of the sample was studied using disk diffusion method. The wettability of the pure and composite fibrous membrane was also studied by measuring the contact angle of water on the membrane. It was observed that the embedded ZnO in the CA was responsible for the hydrophobic nature of the surface.

  16. Cellulose acetate hollow fiber membranes blended with phospholipid polymer and their performance for hemopurification.

    PubMed

    Ye, Sang Ho; Watanabe, Junji; Ishihara, Kazuhiko

    2004-01-01

    Commercially available hollow fiber membranes (HFMs) made from synthetic polymers, including cellulose acetate (CA) HFMs, used as hemopurification membranes, need to improve in hemocompatibility, by suppressing protein adsorption and clot formation. In this study, CA HFMs blended with 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymer (PMB30 composed of MPC and n-butyl methacrylate (BMA)) were prepared by a dry-jet wet spinning process. Their performances were evaluated by characterizing their properties such as structure, permeability and protein adsorption. CA/PMB30-blend HFMs showed structure changes such as increase of porosity, development of large pores and decreasing of the thickness of the active layer. And the structure and permeability of CA/PMB30-blend HFMs were controllable by changing preparation conditions. Also, the CA/PMB30-blend HFMs had good permeability, low protein adsorption and low fouling property during the permeability experiment in comparison with CA HFMs, because the hydrophilic and hemocompatible MPC copolymer (PMB30) existed on the surface of the HFM.

  17. Development and optimization of a capillary zone electrophoresis technique for simultaneous determination of miconazole nitrate and hydrocortisone acetate in a cream pharmaceutical formulation.

    PubMed

    Korany, Mohamed A; Maher, Hadir M; Galal, Shereen M; Ragab, Marwa A A

    2013-01-01

    A simple, fast, inexpensive, and reliable capillary zone electrophoresis (CZE) method for the determination of a mixture of miconazole nitrate (MCZ) and hydrocortisone acetate (HCZ) in a cream formulation has been developed and validated. Optimum conditions were sodium dihydrogen phosphate buffer (50 mM, pH 4) and 30 kV applied voltage in a 85 cm x 75 pm id capillary. Direct UV detection at 230 nm led to adequate sensitivity without interference from the sample excipients. MCZ and HCZ migrated in approximately 165 and 415 s, respectively. The analytical curves had a coefficient of correlation, r, of 0.9999 and 0.9996 for MCZ and HCZ, respectively. The LOD and LOQ were 0.28 and 0.93 microg/mL for MCZ and 0.38 and 1.27 microg/mL for HCZ, respectively. Thus, excellent accuracy and precision were obtained. Recoveries varied from 98 to 102%, and intraday and interday precision, calculated as the RSD, were less than 2.0% for each drug. The proposed CZE method displayed advantageous performance characteristics and can be considered suitable for QC of the MCZ and HCZ cream formulation.

  18. Identification of a Zn(2+)-sensitive component of Ehrlich cell plasma membrane redox system by CHAPS-agarose-polyacrylamide electrophoresis and in situ staining of activity.

    PubMed

    Rodríguez-Caso, L; Rodríguez-Agudo, D; del Castillo-Olivares, A; Márquez, J; Núñez de Castro, I; Medina, M A

    1997-01-01

    A procedure based on CHAPS-agarose-polyacrylamide electrophoresis and in situ staining of activity was used to detect a Zn(2+)-sensitive component of Ehrlich cell plasma membrane redox system. The procedure is so powerful that it allows to use crude plasma membrane fractions and can be easily adapted for use in an electrophoretic approach to the purification of this protein.

  19. Preparation and evaluation of water-in-soybean oil-in-water emulsions by repeated premix membrane emulsification method using cellulose acetate membrane.

    PubMed

    Muhamad, Ida Idayu; Quin, Chang Hui; Selvakumaran, Suguna

    2016-04-01

    The purpose of this study was to investigate the preparation of formulated water- in-soybean oil-in-water emulsions by repeated premix membrane emulsification method using a cellulose acetate membrane. The effect of selective membrane emulsification process parameters (concentration of the emulsifiers, number of passes of the emulsions through the membrane and storage temperature) on the properties and stability of the developed emulsions were also investigated. 1, 3, 6, 8-pyrenetetrasulfonic acid tetrasodium salt (PTSA) was used as a hydrophilic model ingredient for the encapsulation of bioactive substances. W/O emulsions with 7 wt% (weight percentage) PGPR displays homogeneous and very fine dispersions, with the median diameter at 0.640 μm. Meanwhile, emulsions prepared by membrane emulsification (fine W/O/W) showed the highest stability at Tween 80 concentrations of 0.5 wt.% (weight percentage). It concluded that at 7 wt.% (weight percentage) PGPR concentration and 0.5 wt.% (weight percentage) Tween 80 concentrations, the most uniform particles with minimum mean size of oil drops (9.926 μm) were obtained after four passes through the membrane. Thus, cellulose acetate membrane can be used for preparing a stable W/O/W emulsions by repeated premix ME due to low cost and relatively easy to handle.

  20. Fouling propensity and separation efficiency of epoxidated polyethersulfone incorporated cellulose acetate ultrafiltration membrane in the retention of proteins

    NASA Astrophysics Data System (ADS)

    Jayalakshmi, A.; Rajesh, S.; Mohan, D.

    2012-10-01

    Epoxidated polyethersulfone (EPES) incorporated cellulose acetate (CA) ultrafiltration membranes were prepared by diffusion induced precipitation technique in the absence and presence of pore former polyethyleneglycol-600. Effect of blend ratio on the compatibility, thermal stability, mechanical strength, hydrophilicity, morphology, pure water flux, protein adsorption resistance, protein separation efficiency and fouling propensity of the CA/EPES blend membranes was evaluated. Addition of EPES results in the formation of thin separating layer and spongy sub layer in CA/EPES blend membranes. The efficiency of these membranes in the separation of commercially important proteins such as bovine serum albumin, egg albumin, pepsin and trypsin was studied and found to be enhanced as compared to CA membranes. The fouling-resistant capability of the membranes was studied by bovine serum albumin as the model foulant and flux recovery ratio of the membranes were calculated. Attempts have been made to correlate the changes in membrane morphology with pure water flux, hydraulic resistance, thermal and mechanical stability, separation efficiency and antifouling property of the CA/EPES membranes. The optimal combination of CA and EPES, thus allows the preparation of high performance UF membranes which are sufficiently dense to retain proteins and at the same time give economically viable fluxes.

  1. Layer-by-layer structured polysaccharides-based multilayers on cellulose acetate membrane: Towards better hemocompatibility, antibacterial and antioxidant activities

    NASA Astrophysics Data System (ADS)

    Peng, Lincai; Li, Hui; Meng, Yahong

    2017-04-01

    The development of multifunctional cellulose acetate (CA) membranes with enhanced hemocompatibility and antibacterial and antioxidant activities is extremely important for biomedical applications. In this work, significant improvements in hemocompatibility and antibacterial and antioxidant activities of cellulose acetate (CA) membranes were achieved via layer-by-layer (LBL) deposition of chitosan (CS) and water-soluble heparin-mimicking polysaccharides (i.e., sulfated Cantharellus cibarius polysaccharides, SCP) onto their surface. The surface chemical compositions, growth manner, surface morphologies, and wetting ability of CS/SCP multilayer-modified CA membranes were characterized, respectively. The systematical evaluation of hemocompatibility revealed that CS/SCP multilayer-modified CA membranes significantly improved blood compatibility including resistance to non-specific protein adsorption, suppression of platelet adhesion and activation, prolongation of coagulation times, inhibition of complement activation, as well as reduction in blood hemolysis. Meanwhile, CS/SCP multilayer-modified CA membranes exhibited strong growth inhibition against Escherichia coli and Staphylococcus aureus, as well as high scavenging abilities against superoxide and hydroxyl radicals. In summary, the CS/SCP multilayers could confer CA membranes with integrated hemocompatibility and antibacterial and antioxidant activities, which might have great potential application in the biomedical field.

  2. Facile fouling resistant surface modification of microfiltration cellulose acetate membranes by using amino acid L-DOPA.

    PubMed

    Azari, Sara; Zou, Linda; Cornelissen, Emile; Mukai, Yasushito

    2013-01-01

    A major obstacle in the widespread application of microfiltration membranes in the wet separation processes such as wastewater treatment is the decline of permeates flux as a result of fouling. This study reports on the surface modification of cellulose acetate (CA) microfiltration membrane with amino acid L-3,4-dihydroxy-phenylalanine (L-DOPA) to improve fouling resistance of the membrane. The membrane surface was characterised using Fourier transform infrared spectroscopy (FTIR), water contact angle and zeta potential measurement. Porosity measurement showed a slight decrease in membrane porosity due to coating. Static adsorption experiments revealed an improved resistance of the modified membranes towards the adhesion of bovine serum albumin (BSA) as the model foulant. Dead end membrane filtration tests exhibited that the fouling resistance of the modified membranes was improved. However, the effect of the modification depended on the foulant solution concentration. It is concluded that L-DOPA modification is a convenient and non-destructive approach to enable low-BSA adhesion surface modification of CA microfiltration membranes. Nevertheless, the extent of fouling resistance improvement depends on the foulant concentration.

  3. Agarose isoelectric focusing can improve resolution of membrane proteins in the two-dimensional electrophoresis of bacterial proteins.

    PubMed

    Altenhofer, Pia; Schierhorn, Angelika; Fricke, Beate

    2006-10-01

    2-D separation of bacterial membrane proteins is still difficult despite using high-resolution IPG-IEF/SDS-PAGE. We were searching for alternative methods to avoid typical problems such as precipitation, low solubility, and aggregation of membrane proteins in the 1-D separation with IPG-IEF. Blue native electrophoresis (BNE) and agarose IEF (A-IEF) were tested for their separation capacity and their capability of replacing IPG-IEF in the first dimension. SDS-PAGE was chosen for the second dimension on account of its outstanding resolution. We could confirm that only A-IEF was a useful replacement for the IPG-IEF in the first dimension resulting in 2-D protein distributions with additional membrane protein spots not being found after IPG-IEF/SDS-PAGE. A second interesting result was that the agarose IEF mediates the possibility of separation of membrane proteins in a partially native state in the first dimension. This native A-IEF resulted in drastically changed spot patterns with an acidic shift of nearly all spots and divergent distribution of proteins compared to non-native A-IEF and IPG-IEF. We found out that native and non-native A-IEF are powerful tools to supplement IPG-IEF/SDS-PAGE.

  4. Performance of cellulose acetate - polyethersulphone blend membrane prepared using microwave heating for palm oil mill effluent treatment.

    PubMed

    Idris, A; Ahmed, I; Jye, H W

    2007-01-01

    The objective of this research is to investigate the performance of blend cellulose acetate (CA)-polyethersulphone (PES) membranes prepared using microwave heating (MWH) techniques and then compare it with blend CA-PES membranes prepared using conventional heating (CH) methods using bovine serum albumin solution. The superior membranes were then used in the treatment of palm oil mill effluent (POME). Various blends of CA-PES have been blended with PES in the range of 1-5 wt%. This distinctive series of dope formulations of blend CA/PES and pure CA was prepared using N, N-dimethylformamide (DMF) as solvent. The dope solution was prepared by MW heating for 5 min at a high pulse and the membranes were prepared by phase inversion method. The performances of these membranes were evaluated in terms of pure water and permeate flux, percentage removal of total suspended solids (TSS), chemical oxygen demand (COD) and biochemical oxygen demand (BOD). The results indicate that blend membranes prepared using the microwave technique is far more superior compared to that prepared using CH. Blend membranes with 19% CA, 1-3% PES and 80% of DMF solvent were found to be the best membrane formulation.

  5. Comparison of polycarbonate and cellulose acetate membrane filters for isolation of Campylobacter concisus from stool samples.

    PubMed

    Nielsen, Hans Linde; Engberg, Jørgen; Ejlertsen, Tove; Nielsen, Henrik

    2013-08-01

    One thousand seven hundred ninety-one diarrheic stool samples were cultivated for Campylobacter spp. We found a high prevalence of Campylobacter concisus with use of a polycarbonate filter (n = 114) compared to a cellulose acetate filter (n = 79) (P < .0001). The polycarbonate filter is superior to the commonly used cellulose acetate filter for detection of C. concisus.

  6. Outer membrane protein profiles and multilocus enzyme electrophoresis analysis for differentiation of clinical isolates of Proteus mirabilis and Proteus vulgaris.

    PubMed

    Kappos, T; John, M A; Hussain, Z; Valvano, M A

    1992-10-01

    Outer membrane protein (MP) profiles and multilocus enzyme electrophoresis (MEE) analysis were used as tools for differentiating clinical isolates of Proteus spp. Fourteen distinct MP profiles were established by sodium dodecyl sulfate-urea polyacrylamide gel electrophoresis in 54 clinical isolates of Proteus spp. (44 strains identified as P. mirabilis and 10 strains identified as P. vulgaris). Forty-one isolates of P. mirabilis and eight isolates of P. vulgaris were grouped within six and three MP profiles, respectively. The remaining P. mirabilis and P. vulgaris isolates had unique profiles. MEE analysis was used to further discriminate among the strains belonging to the same MP groups. Thirty-five distinct electrophoretic types (ETs) were identified among P. mirabilis isolates. The isolates of P. mirabilis from the four most common MP groups were subgrouped into 30 ETs. All of the P. vulgaris strains had unique ETs. The results suggest that upon biochemical classification of Proteus isolates as P. mirabilis or P. vulgaris, further differentiation among strains of the same species can be obtained by the initial determination of MP profiles followed by MEE analysis of strains with identical MPs.

  7. Integrated multilayer microfluidic device with a nanoporous membrane interconnect for online coupling of solid-phase extraction to microchip electrophoresis.

    PubMed

    Long, Zhicheng; Shen, Zheng; Wu, Dapeng; Qin, Jianhua; Lin, Bingcheng

    2007-12-01

    An integrated microfluidic device was developed for online coupling of solid-phase extraction to microchip electrophoresis (chip SPE-CE). With a nanoporous membrane sandwiched between two PDMS substrates, SPE preconcentration and electrophoretic separation can be carried out in upper and lower fluidic layers, separately and sequentially. During the SPE process, the thin membrane can act as a fluid isolator to prevent intermixing between two fluidic channels. However, when a pulse voltage is applied, the membrane becomes a gateable interconnect so that a small plug of concentrated analytes can be online injected into the lower channel for subsequent separations. This multilayer design provides a universal solution to online SPE-CE hyphenation. Both electroosmotic flow and hydrodynamic pumps have been adopted for SPE operation. SPE was performed on a 2.5 mm long microcolumn, with two weirs on both sides to retain the C(18)-coated silica beads. Rhodamine 123 and FITC-labelled ephedrine were used to test the operational performance of the hyphenation system. High separation efficiency and thousand-fold signal enhancement were achieved.

  8. Preparation of polyvinylidene fluoride/cellulose acetate blend membrane with polyethylene glycol additive for apple juice clarification

    NASA Astrophysics Data System (ADS)

    Fitri, Shatila Jihadiyah; Widiastuti, Nurul

    2017-03-01

    Polyvinylidene Fluoride (PVDF)/Cellulose Acetate (CA) blend membrane with polyethylene (PEG) addition of casting solution were synthesised to determine its morphology. This purpose of this research is to investigate the effect of PEG addition to membrane performance and its application to the clarification of apple juice. The membranes were prepared from polymer blends of CA and PVDF, dimethyl acetamide (DMAc) as solvent, and PEG as additive. Phase inversion was used to prepare membranes by mixing the polymer blends, solvent and additive to be reacted at temperature 60 °C for 24 hours. The variation of PEG weight percentage were 0, 1 wt%, 3 wt%, and 5 wt%. The addition of PEG increased porosity and fluxes, but decreased membrane rejection. Scanning Electron Microscope (SEM), Atomic Force Microscope (AFM), and Fourier Transform Infrared (FTIR) were applied to evaluate the morphology of membranes, which investigated increasing of pore size, pore distribution, and surface roughness. Apple juice clarification by membrane with 1% PEG was obtained 95,1% clearer than the pure sample.

  9. Fast analysis of glycosaminoglycans by microchip electrophoresis with in situ fluorescent detection using ethidium bromide.

    PubMed

    Matsuno, Yu-ki; Kinoshita, Mitsuhiro; Kakehi, Kazuaki

    2005-03-09

    We analyzed some glycosaminoglycans and natural and artificial acidic polysaccharides using microchip electrophoresis in the buffer containing ethidium bromide, and found that they were successfully separated and detected within 150 s with comparable sensitivity with that of conventional electrophoresis using cellulose acetate membrane. We applied the technique to the analysis of glycosaminoglycans in pharmaceutical preparations and also in cultured cancer cells. Rapidness and easy operation of the proposed technique are quite useful for routine analysis of glycosaminoglycans.

  10. Quantifying contribution of synthrophic acetate oxidation to methane production in thermophilic anaerobic reactors by membrane inlet mass spectrometry.

    PubMed

    Mulat, Daniel Girma; Ward, Alastair James; Adamsen, Anders Peter S; Voigt, Niels Vinther; Nielsen, Jeppe Lund; Feilberg, Anders

    2014-02-18

    A unique method was developed and applied for monitoring methanogenesis pathways based on isotope labeled substrates combined with online membrane inlet quadrupole mass spectrometry (MIMS). In our study, a fermentation sample from a full-scale biogas plant fed with pig and cattle manure, maize silage, and deep litter was incubated with 100 mM of [2-(13)C] sodium acetate under thermophilic anaerobic conditions. MIMS was used to measure the isotopic distribution of dissolved CO2 and CH4 during the degradation of acetate, while excluding interference from water by applying a cold trap. After 6 days of incubation, the proportion of methane derived from reduction of CO2 had increased significantly and reached up to 87% of total methane, suggesting that synthrophic acetate oxidation coupled to hydrogenotrophic methanogenesis (SAO-HM) played an important role in the degradation of acetate. This study provided a new approach for online quantification of the relative contribution of methanogenesis pathways to methane production with a time resolution shorter than one minute. The observed contribution of SAO-HM to methane production under the tested conditions challenges the current widely accepted anaerobic digestion model (ADM1), which strongly emphasizes the importance of the acetoclastic methanogenesis.

  11. Fabrication of tethered carbon nanotubes in cellulose acetate/polyethylene glycol-400 composite membranes for reverse osmosis.

    PubMed

    Sabir, Aneela; Shafiq, Muhammad; Islam, Atif; Sarwar, Afsheen; Dilshad, Muhammad Rizwan; Shafeeq, Amir; Zahid Butt, Muhammad Taqi; Jamil, Tahir

    2015-11-05

    In this study pristine multi-walled carbon nanotubes (MWCNTs) were surface engineered (SE) in strong acidic medium by oxidation purification method to form SE-MWCNT. Five different amount of SE-MWCNT ranging from 0.1 to 0.5 wt% were thoroughly and uniformly dispersed in cellulose acetate/polyethylene glycol (CA/PEG400) polymer matrix during synthesis of membrane by dissolution casting method. The structural analysis, surface morphology and roughness was carried out by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and atomic force microscopy (AFM), respectively, which showed that the dispersed SE-MWCNT was substantially tethered in CA/PEG400 polymer matrix membrane. The thermogravimetric analysis (TGA) of membranes also suggested some improvement in thermal properties with the addition of SE-MWCNT. Finally, the performance of these membranes was assessed for suitability in drinking water treatment. The permeation flux and salt rejection were determined by using indigenously fabricated reverse osmosis pilot plant with 1000 ppm NaCl feed solution. The results showed that the tethered SE-MWCNT/CA/PEG400 polymer matrix membrane, with strong SE-MWCNTs/polymer matrix interaction, improved the salt rejection performance of the membrane with the salt rejection of 99.8% for the highest content of SE-MWCNT.

  12. Development of cellulose acetate propionate membrane for separation of ethanol and ethyl tert-butyl ether mixtures

    SciTech Connect

    Luo, G.S.; Niang, M.; Schaetzel, P.

    1997-04-01

    For pervaporation separation of ethanol and ethyl tert-butyl ether mixtures, a cellulose acetate propionate membrane was chosen as the experimental membrane because of its high selectivity and good mass fluxes. The properties of the membranes were evaluated by the pervaporation separation of mixtures of ethyl tert-butyl ether/ethanol and the sorption experiments. The experimental results showed that the selectivity and the permeates depend on the ethanol concentration in the feed and the experimental temperature. With increases of the ethanol weight fraction in the feed and the temperature, the total and partial mass fluxes increased. With respect to the temperature, ethanol mass flux obeys the Arrhenius equation. The selectivity of this membrane decreases as the temperature and the ethanol concentration in the feed increase. This membrane shows special characteristics at the azeotropic composition. In the vicinity of the azeotropic point, minimum values of ethanol concentration in the permeate and in sorption solution are obtained. The swelling ratios increase when temperature and the ethanol concentration in the feed are increasing. The ethanol concentration in the sorption solution is also influenced by the temperature and the mixture`s composition. When the temperature increases, the sorption selectivity of the membrane decreases.

  13. Diffusive transfer to membranes as an effective interface between gel electrophoresis and mass spectrometry

    NASA Astrophysics Data System (ADS)

    Ogorzalek Loo, Rachel R.; Mitchell, Charles; Stevenson, Tracy I.; Loo, Joseph A.; Andrews, Philip C.

    1997-12-01

    Diffusive transfer was examined as a blotting method to transfer proteins from polyacrylamide gels to membranes for ultraviolet matrix-assisted laser desorption ionization (MALDI) mass spectrometry. The method is well-suited for transfers from isoelectric focusing (IEF) gels. Spectra have been obtained for 11 pmol of 66 kDa albumin loaded onto an IEF gel and subsequently blotted to polyethylene. Similarly, masses of intact carbonic anhydrase and hemoglobin were obtained from 14 and 20 pmol loadings. This methodology is also compatible with blotting high molecular weight proteins, as seen for 6 pmol of the 150 kDa monoclonal antibody anti-[beta]-galactosidase transferred to Goretex. Polypropylene, Teflon, Nafion and polyvinylidene difluoride (PVDF) also produced good spectra following diffusive transfer. Only analysis from PVDF required that the membrane be kept wet prior to application of matrix. Considerations in mass accuracy for analysis from large-area membranes with continuous extraction and delayed extraction were explored, as were remedies for surface charging. Vapor phase CNBr cleavage was applied to membrane-bound samples for peptide mapping.

  14. Electrophoresis and isoelectric focusing of whole cell and membrane proteins from the extremely halophilic archaebacteria

    NASA Technical Reports Server (NTRS)

    Stan-Lotter, Helga; Lang, Frank J., Jr.; Hochstein, Lawrence I.

    1989-01-01

    The subunits from two purified halobacterial membrane enzymes (ATPase and nitrate reductase) behaved differently with respect to isoelectric focusing, silver staining and interaction with ampholytes. Differential behavior was also observed in whole cell proteins from Halobacterium saccharovorum regarding resolution in two-dimensional gels and silver staining. It is proposed that these differences reflect the existence of two classes of halobacterial proteins.

  15. Development of Low Cost Membranes (Ta, Nb & Cellulose Acetate) for H2/CO2 Separation in WGS Reactors

    SciTech Connect

    Seetala, Naidu; Siriwardane, Upali

    2011-12-15

    The main aim of this work is to synthesize low temperature bimetallic nanocatalysts for Water Gas Shift reaction (WGS) for hydrogen production from CO and steam mixture; and develop low-cost metal (Nb/Ta)/ceramic membranes for H2 separation and Cellulose Acetate membranes for CO2 separation. .

  16. Effect of gossypol-acetic acid on calcium transport and ATPase activity in plasma membranes from ram and bull spermatozoa.

    PubMed

    Breitbart, H; Rubinstein, S; Nass-Arden, L

    1984-10-01

    The effects of gossypol acetic acid on the activity of Mg-ATPase and Ca-Mg-ATPase and on calcium uptake by plasma membranes from ram and bull spermatozoa were examined. The three parameters were almost completely inhibited by 10 microM gossypol for both ram and bull sperm. In order to assess the effects of higher gossypol concentrations isolated membrane vesicles were loaded with calcium by operating the ATP-dependent calcium pump after which gossypol was added and calcium uptake followed. At 10 microM gossypol, additional calcium uptake was 85% inhibited while at 40 microM a release of the accumulated calcium was observed. The inhibitory effect of 10 microM gossypol was almost completely reversible by simple dilution of gossypol-treated membranes, whilst at 40 microM the effect was only 50% reversible. The data show a high degree of similarity between bull and ram, suggesting minimal differences between the two species as far as the structure and function of the sperm plasma membrane is concerned.

  17. Removal of aqueous Hg(II) and Cr(VI) using phytic acid doped polyaniline/cellulose acetate composite membrane.

    PubMed

    Li, Renjie; Liu, Lifen; Yang, Fenglin

    2014-09-15

    Conductive composite membrane-phytic acid (PA) doped polyaniline (PANI)/cellulose acetate (CA) (PANI-PA/CA) was prepared in a simple and environmental-friendly method, in which aniline was blended with CA/PA solution and polymerized before the phase conversion. The resultant composite membranes were characterized by SEM, EDX, FTIR-ATR, BET and electrical resistance measurements. When used as adsorbent for Hg(II) and Cr(VI) ions, the prepared composite membrane exhibits excellent adsorption capability. The adsorption of Hg(II) and Cr(VI) follows a pseudo-second-order kinetic model and best fits the Langmuir isotherm model, with the maximum adsorption capacity reaching 280.11 and 94.34 mg g(-1), respectively. The heavy metal loaded composite membrane can be regenerated and reused after treatment with acid or alkali solution, making it a promising and practical adsorbent for Hg(II) and Cr(VI) removal. Tests with river water were also carried out, indicating good performance and application.

  18. Water in polymer membranes. 4. Raman scattering from cellulose acetate films

    SciTech Connect

    Scherer, J.R.; Bailey, G.F.; Kint, S.; Young, R.; Malladi, D.P.; Bolton, B.

    1985-01-17

    Raman scattering was observed from thin film optical waveguides of cellulose acetate exposed to water vapor from 0% to 100% relative humidity (RH), and from dilute solutions of water in methyl acetate. Spectra of cellulose acetate (CA398, 39.8% acetyl) at low RH and cellulose triacetate (CTA) at low and high RH are consistent with the presence of water monomers that are weakly hydrogen bonded to acetyl C=O groups. Differences between the spectra of water in CA398 and CTA at low RH are attributed to sequential hydrogen bonding involving OH groups in CA398. At high RH, CA398 and CTA (to a lesser extent) show bands attributed to water/water interactions that are similar to those found in sequentially hydrogen-bonded hydrates. CA398 films that are annealed at high temperatures exhibit decreased water/water interactions at high RH. Exposure of CA398 films to D/sub 2/O converts > 90% of all polymer OH groups to OD groups. This indicates that water is accessible to nearly all regions of the polymer containing OH groups. Annealing does not alter this accessibility but does reduce the total water content by roughly half, at 100% RH. Hydrogen-bonded C=O groups are associated with a band centered at 1731 cm/sup -1/ which increases in intensity with increasing water content in the film but does not shift in frequency. 38 references, 16 figures, 1 table.

  19. Comparison of radial immunodiffusion and alkaline cellulose acetate electrophoresis for quantitating elevated levels of fetal hemoglobin (HbF): application to evaluating patients with sickle cell disease treated with hydroxyurea.

    PubMed

    Schultz, J C

    1999-01-01

    Radial immunodiffusion (RID), alkaline cellulose acetate electrophoresis, and high-performance liquid chromatography (HPLC) were compared for quantitating the elevated (> 10%) level of fetal hemoglobin (HbF) found in the red blood cells of sickle cell disease patients undergoing treatment with hydroxyurea. HPLC- and electrophoresis-determined values were comparable. The RID-determined values were higher, in many cases twofold higher. False high HbF values would be misleading in assessing the effectiveness of hydroxyurea therapy in sickle cell disease patients. We subsequently initiated an examination of the variation in HbF values due to the use of different HbF radial immunodiffusion QUIPlates and different positions within a single plate in an attempt to determine the cause of these discrepancies. Within-run precision studies indicated that significantly different size precipitin rings were obtained depending upon which area of the plate the hemolysate containing antigen (HbF) was applied. A common feature associated with poor precision plates was a marked difference in degree of coloration of gel throughout the plate. Spuriously high HF concentrations were obtained with antigen (HbF) placed in wells located in the lighter colored gel area while antigen placed in wells in the darker colored area of the agarose gel bed were more in agreement with the electrophoretically determined HbF concentrations. The variation in HbF values was significantly greater in the diluted (HbF QUIPlate Diluent) samples than in the neat samples even on plates of uniform gel coloration. As a result of this study, we will continue to monitor high HbF levels by densitometry following alkaline cellulose acetate electrophoresis.

  20. Preparation of sealed tonoplast and plasma-membrane vesicles from Catharanthus roseus (L.) G. Don. cells by free-flow electrophoresis.

    PubMed

    Canut, H; Baudracco, S; Cabané, M; Boudet, A M; Marigo, G

    1991-07-01

    Highly purified tonoplast and plasmamembrane vesicles were isolated from microsomes of Catharanthus roseus (L.) G. Don. by preparative free-flow electrophoresis. The relative amounts of tonoplast and plasma-membrane vesicles in the total microsomes varied with the pH of the grinding medium. The most electronegative fractions were identified as tonoplast using nitrate-inhibited, azide-resistant Mg(2+)-ATPase and pyrophosphatase activities as enzyme markers. The least electronegative fractions were identified as plasma membrane using glucan-synthase-II and UDPG:sterolglucosyl-transferase activities as enzyme markers. Other membrane markers, latent inosine-5'-diphosphatase (Golgi), NADPH-cytochrome-c reductase (ER) and cytochrome-c oxidase (mitochondria) were recovered in the fractions intermediate between tonoplast and plasma membrane and did not contaminate either the tonoplast or the plasma-membrane fractions. In the course of searching for a reliable marker for tonoplast, the pyrophosphatase activity was found to be essentially associated with the tonoplast fractions purified by free-flow electrophoresis from C. roseus and other plant materials. The degree of sealing of the tonoplast and plasmamembrane vesicles was probed by their ability to pump protons (measurements of quinacrine quenching) and to generate a membrane potential (absorption spectroscopy of Oxonol VI). A critical evaluation of vesicles sidedness is presented.

  1. ADSORPTION AND MEMBRANE SEPARATION MEASUREMENTS WITH MIXTURES OF ETHANOL, ACETIC ACID, AND WATER

    EPA Science Inventory

    Biomass fermentation produces ethanol and other renewable biofuels. Pervaporation using hydrophobic membranes is potentially a cost-effective means of removing biofuels from fermentation broths for small- to medium-scale applications. Silicalite-filled polydimethylsiloxane (PDMS)...

  2. Lateral electrophoresis and diffusion of Concanavalin A receptors in the membrane of embryonic muscle cell

    PubMed Central

    Poo, M. M.; Poo, W. J.; Lam, J. W.

    1978-01-01

    A uniform electric field of 10 V/cm applied across the surface of embryonic toad Xenopus muscle cells results in the asymmetric accumulation of concanavalin A (Con A) receptors toward one side of the cells within 10 min, as visualized by postfield fluorescent Con A labeling. This field produces an extracellular voltage difference of 20 mV across these 20-microns wide cells. The effect is reversible in two respects: (a) Additional exposure of the cell to the same field of opposite polarity for 10 min completely reverses the asymmetric accumulation to the other side of the cell. (b) Relaxation occurs after the removal of the field and results in complete recovery of the uniform distribution in 30 min. Both the accumulation and the recovery movements are independent of cell metabolism, and appear to be electrophoretic and diffusional in nature. The threshold field required to induce a detectable accumulation by the present method is between 1.0 and 1.5 V/cm (corresponding to a voltage difference of 2-3 mV across a 20-microns wide cell). The electrophoretic mobility of the most mobile population of nonliganded Con A receptors is estimated to be about 2 x 10(-3) microns/s per V/cm, while their diffusion coefficient is in the range of 4-7 x 10(-10) cm2/s. Extensive accumulation of the Con A receptors by an electric field results in the formation of immobile aggregates. The Con A receptors appear to consist of a heterogeneous population of membrane components different in their charge properties, mobility, and capability in forming aggregates. PMID:10605452

  3. Coupling sodium dodecyl sulfate-capillary polyacrylamide gel electrophoresis with matrix-assisted laser desorption ionization time-of-flight mass spectrometry via a poly(tetrafluoroethylene) membrane.

    PubMed

    Lu, Joann J; Zhu, Zaifang; Wang, Wei; Liu, Shaorong

    2011-03-01

    Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) is a fundamental analytical technique for proteomic research, and SDS-capillary gel electrophoresis (CGE) is its miniaturized version. Compared to conventional slab-gel electrophoresis, SDS-CGE has many advantages such as increased separation efficiency, reduced separation time, and automated operation. SDS-CGE is not widely accepted in proteomic research primarily due to the difficulties in identifying the well-resolved proteins. MALDI-TOF-MS is an outstanding platform for protein identifications. Coupling the two would solve the problem but is extremely challenging because the MS detector has no access to the SDS-CGE-resolved proteins and the SDS interferes with MS detection. In this work we introduce an approach to address these issues. We discover that poly(tetrafluoroethylene) (PTFE) membranes are excellent materials for collecting SDS-CGE-separated proteins. We demonstrate that we can wash off the SDS bound to the collected proteins and identify these proteins on-membrane with MALDI-TOF-MS. We also show that we can immunoblot and Coomassie-stain the proteins collected on these membranes.

  4. Grafting of cellulose acetate with ionic liquids for biofuel purification by a membrane process: Influence of the cation.

    PubMed

    Hassan Hassan Abdellatif, Faten; Babin, Jérôme; Arnal-Herault, Carole; David, Laurent; Jonquieres, Anne

    2016-08-20

    A new strategy was developed for grafting ionic liquids (ILs) onto cellulose acetate in order to avoid IL extraction and improve its performance for ethyl tert-butyl ether (ETBE) biofuel purification by the pervaporation membrane process. This work extended the scope of IL-containing membranes to the challenging separation of organic liquid mixtures, in which these ILs were soluble. The ILs contained the same bromide anion and different cations with increasing polar feature. The membrane properties were strongly improved by IL grafting. Their analysis in terms of structure-property relationships revealed the influence of the IL content, chemical structure and chemical physical parameters α, β, π* in the Kamlet-Taft polarity scale. The ammonium IL led to the best normalized flux of 0.182kg/m(2)h for a reference thickness of 5μm, a permeate ethanol content of 100% and an outstanding infinite separation factor for the azeotropic mixture EtOH/ETBE at 50°C.

  5. Integrated photografted molecularly imprinted polymers with a cellulose acetate membrane for the extraction of melamine from dry milk before HPLC analysis.

    PubMed

    Akbari-Adergani, Behrouz; Sadeghian, Gholam-Hossein; Alimohammadi, Alireza; Esfandiari, Zahra

    2017-03-01

    In this study, a new separation technique based on membrane extraction is described for the determination of melamine in dry milk. The water-compatible cellulose acetate membrane, which is photografted by melamine imprinted nanospheres, was prepared by placing the membrane into the polymerization solution containing methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as cross-linker, acetonitrile as porogen, and melamine as the template molecule. The characterization of the polymeric membrane was performed by Fourier transmission infrared spectroscopy and scanning electron microscopy. This integrated composite membrane was used as a solid-phase extraction medium for the extraction of melamine from dry milk samples. Various parameters affecting the extraction efficiency of the membrane were evaluated. The results showed higher binding capacity for melamine imprinted membranes in comparison with the nonimprinted membranes. High-performance liquid chromatography analysis showed that the extraction of melamine from dry milk by the photografted cellulose acetate membrane had a linear calibration curve in the range of 0.02-11.80 μg/mL with an excellent precision of 2.73%. The limit of detection and quantification of melamine was 0.007 and 0.020 μg/mL, respectively. The recoveries of melamine were in the range of 88.7-94.8%.

  6. Phosphohydrolase activity of the isolated, brush-border membrane of Hymenolepis diminuta (Cestoda) following sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis.

    PubMed

    Pappas, P W

    1980-12-01

    Following electrophoresis of isolated, brush-border membranes of Hymenolepis diminuta on SDS-polyacrylamide gels, three distinct areas of alpha-naphthyl phosphate (NP) hydrolysis were detected; these corresponded to proteins with molecular weights of 106,800, 172,700, and greater than 340,000 Daltons. Hydrolysis of NP was inhibited by adenosine triphosphate, adenosine;5'-monophosphate, p-nitrophenyl-phosphate, glucose-1-phosphate, glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-diphosphate, molybdate, ethylenediaminetetraacetate (EDTA), and ethyleneglycol-bis-(beta-amino-ethyl)-N,N'-tetraacetate (EGTA), but not by fluoride. Inhibition of NP hydrolysis by EDTA was relieved in the presence of Mg++ or Ca++. Heating the isolated, brush-border membrane in the presence of SDS for 5 min at 95 C destroyed all enzymatic activity. These characteristics indicated that the enzyme(s) responsible for NP hydrolysis (following separation of membrane proteins by SDS-polyacrylamide gel electrophoresis) were the same enzymes responsible for the phosphohydrolase activity associated with intact and solubilized, brush-border membrane preparations of H. diminuta.

  7. Permeation of gas mixtures in cellulose acetate membranes - practical approach to predict the permeation rate CO/sub 2//CH/sub 4/ mixture

    SciTech Connect

    Fouda, A.E.; Matsuura, T.; Lui, A.

    1988-10-01

    Dry cellulose acetate reverse osmosis membranes of different porosities are prepared by using the solvent exchange method and then shrunk at various temperatures. Permeation of single gases and gas mixtures of CO/sub 2/ and CH/sub 4/ through these membranes were investigated at various upstream pressures up to 2.4 MPa. The permeation data of a reference gas usually helium was used to characterize the membrane and determine the flow parameters which can be used to predict the performance of that membrane in separating gas mixtures. The Surface Force - Pore Flow model developed in previous investigations can be used to predict the membrane performance using the above method. The prediction using the characterization parameters of the reference gas proved to be unsatisfactory in most cases, since the surface force is highly dependent on the interaction between the specific gas component in the mixture and the membrane.

  8. Fluorescence Detection In Electrophoresis

    NASA Astrophysics Data System (ADS)

    Swarner, Susan

    1988-04-01

    Fluorescence detection is in common usage in forensic science laboratories for the visualization of three enzyme markers. The fluorogenic substrates, 4-methylumbelliferyl phosphate, 4-methylutbel-liveryl acetate, and fluorecein diacetate, are acted upon by the enzymes Erythrocyte Acid Phospha, tase, Esterase-D, and Carbonic Anhydrase-III, respectively, to produce compounds visible to the analyst when viewed with transmitted UV light at 365 nm. Additionally, the choice of fluorogenic corn, pounds may help detect a specific enzyme from a related enzyme. One of the responsibilities of a forensic science laboratory may be the analysis of blood for genetically controlled polymorphic enzymes and protein markers. The genetic markers are said to be polymorphic because each exhibits types which can be differentiated and allows for the inclusion or exclusion of possible-donors of the blood. Each genetic marker can be separated into these recognizable types by electrophoresis, a technique which separates compounds based on electrical charges. Electrophoresis is conducted by placing a portion or extract of each bloodstain into a support medium which will conduct electricity. This is known as a plate or membrane. By controlling the pH of the buffer and the potential that is applied to the plate, the analyst can achieve separation of the types within an enzyme marker. The types appear as differing patterns of bands. Once the bloodstain has been subjected to electrophoresis, the enzymes must be visualized. This is generally best accomplished by using the specific activity of the enzyme. For the enzymes described in the present work, the visualization is performed by over-layering the plate with a piece of filter paper that 'has been saturated with the appropriate non-fluorescent substrate and buffer. The bands of enzyme, which is now in discrete patterns, will act upon the non-fluorescent substrate to create a fluorescent compound. The plate is then viewed with transmitted UV

  9. Enhancement of acetate productivity in a thermophilic (55 °C) hollow-fiber membrane biofilm reactor with mixed culture syngas (H2/CO2) fermentation.

    PubMed

    Wang, Yun-Qi; Yu, Shi-Jin; Zhang, Fang; Xia, Xiu-Yang; Zeng, Raymond J

    2017-03-01

    Conversion of organic wastes to syngas is an attractive way to utilize wastes. The produced syngas can be further used to produce a variety of chemicals. In this study, a hollow-fiber membrane biofilm reactor with mix cultures was operated at 55 °C to convert syngas (H2/CO2) into acetate. A high concentration of acetate (42.4 g/L) was reached in batch experiment while a maximum acetate production rate of 10.5 g/L/day was achieved in the continuous-flow mode at hydraulic retention time (HRT) of 1 day. Acetate was the main product in both batch and continuous-flow experiments. n-Butyrate was the other byproduct in the reactor. Acetate accounted for more than 98.5 and 99.1% of total volatile fatty acids in batch and continuous modes, respectively. Illumina Miseq high-throughput sequencing results showed that microorganisms were highly purified and enriched in the reactor. The main genus was Thermoanaerobacterium (66% of relative abundance), which was usually considered as H2 producer in the literature, however, likely played a role as a H2 consumer in this study. This study provides a new method to generate the high producing rate and purity of acetate from syngas.

  10. Effect of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) upon membrane ionic exchanges in sea urchin eggs

    SciTech Connect

    Ciapa, B.; Payan, P. ); Allemand, D. )

    1989-12-01

    The effect of TPA (12-O-tetradecanoylphorbol-13-acetate) upon ionic exchanges was investigated in eggs of the sea urchin Arbacia lixula. Ouabain-sensitive {sup 86}Rb uptake and amiloride-sensitive {sup 24}Na influx were dramatically stimulated after TPA addition, indicating an enhancement of total ionic permeabilities. Stimulation by TPA of both Na{sup +}/H{sup +} and Na{sup +}/K{sup +} exchanges was canceled by amiloride, suggesting that activation of protein kinase C elicits, via Na{sup +}/H{sup +} activity, stimulation of the sodium pump. However, TPA did not stimulate sodium pump activity and Na{sup +}/H{sup +} exchange at the same rate as fertilization, probably because of an absence of calcium-dependent events. Further fertilization of TPA pretreated eggs triggered an enhancement of sodium pump activity when the TPA treatment duration did not exceed 10 minutes. It is suggested that TPA activates preexisting transporting mechanisms in plasma membranes of unfertilized eggs (Na{sup +} stat, pH stat).

  11. Effect of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TTPA) upon membrane ionic exchanges in sea urchin eggs.

    PubMed

    Ciapa, B; Allemand, D; Payan, P

    1989-12-01

    The effect of TPA (12-O-tetradecanoylphorbol-13-acetate) upon ionic exchanges was investigated in eggs of the sea urchin Arbacia lixula. Ouabain-sensitive 86Rb uptake and amiloride-sensitive 24Na influx were dramatically stimulated after TPA addition, indicating an enhancement of total ionic permeabilities. Stimulation by TPA of both Na+/H+ and Na+/K+ exchanges was canceled by amiloride, suggesting that activation of protein kinase C elicits, via Na+/H+ activity, stimulation of the sodium pump. However, TPA did not stimulate sodium pump activity and Na+/H+ exchange at the same rate as fertilization, probably because of an absence of calcium-dependent events. Further fertilization of TPA-pretreated eggs triggered an enhancement of sodium pump activity when the TPA treatment duration did not exceed 10 min. It is suggested that TPA activates preexisting transporting mechanisms in plasma membranes of unfertilized eggs (Na+ pump, Na+/H+ exchange) without eliciting corresponding regulatory mechanisms (Na+ stat, pH stat).

  12. Utilization of composite membrane polyethyleneglycol-polystyrene-cellulose acetate from pineapple leaf fibers in lowering levels of methyl orange batik waste

    NASA Astrophysics Data System (ADS)

    Delsy, E. V. Y.; Irmanto; Kazanah, F. N.

    2017-02-01

    Pineapple leaves are agricultural waste from the pineapple that the fibers can be utilized as raw material in cellulose acetate membranes. First, made pineapple leaf fibers into pulp and then converted into cellulose acetate by acetylation process in four stages consisting of activation, acetylation, hydrolysis and purification. Cellulose acetate then used as the raw material to manufacture composite membrane with addition of polystyrene and poly (ethylene glycol) as porogen. Composite membrane is made using phase inversion method with dichloromethane-acetone as a solvent. The result of FTIR analysis (Fourier transform infra-red) showed that the absorption of the carbonyl group (C=O) is at 1643.10 cm-1 and acetyl group (C–O ) at 1227.01 cm-1, with a molecular weight of 8.05 x 104 g/mol and the contents (rate) of acetyl is 37.31%. PS-PEG-CA composite membrane had also been characterized by measuring the water flux values and its application to decrease methyl orange content (level) in batik waste. The results showed that the water flux value is of 25.62 L/(m2.hour), and the decrease percentage of methyl orange content in batik waste is 71.53%.

  13. Electrophoresis '88

    SciTech Connect

    Schafer-Nielsen, C.

    1988-01-01

    This book contains the proceedings of the Sixth Meeting of the International Electrophoresis Society, held in July 1988 in Copenhagen. Papers are grouped into seven sections: Theoretical Developments, Isoelectric Focusing, Free-Flow Electrophoresis, Gel and Staining Techniques, Automated Densitometry, and Electrotransfer/Electrophoresis of DNA. The references date from the 1960s to the present. An author index is included.

  14. Studies on electrochemical characterization and performance prediction of cellulose acetate and Zeocarb-225 composite membranes in aqueous NaCl solutions.

    PubMed

    Tiwari, A K; Ahmad, Suhail

    2006-06-01

    We have mixed cellulose acetate and Zeocarb-225 in different ratios, leading to the preparations of Membrane-1 and Membrane-2. Membrane potential, water content, and conductance measurements have been carried out to estimate and analyze the data in terms of equilibria and important electrochemical parameters. The Donnan equilibrium has been incorporated to estimate the activity coefficient of counterions, y(p)M, and solute, y(+/-)M in the membrane phase along with the parameter, so called varphi expressing non-ideality. Dependence of the extent of hydrophilicity of both membranes on mean electrolyte concentrations has been examined. Selectivity in membranes is discussed in terms of dissociation equilibria, K(d)s and K(d)f. It has been found that membrane surface charge density sigma(s) increases with increasing of external NaCl concentration. Dependence of water transport number and cationic transport number on electrolyte concentration shows a similar trend of variation. At higher mean concentration of electrolyte, water transport number in Membrane-2 has a negative value. Membrane-2 has a higher value of water transport number than Membrane-1. The entropy production due to solute and water transport has been quantified for both the membranes in the light of nonequilibrium thermodynamics. The various type of interactions such as solute-membrane, solute-water, and water-membrane are analyzed in terms of friction coefficients (f(ij)) of Spiegler's frictional pore model. In our case, an f(wm) < f(sm) < f(sw)-like trend is observed in both membranes. These frictional coefficients show close dependence on external electrolyte concentrations. Pore potential values of Membrane-1 and Membrane-2 have been worked out using the Poisson-Boltzmann equation. In both systems pore potential values increase with increasing mean electrolyte concentrations. The transport through Membrane-1 and Membrane-2 tends to follow diffusion-control criteria, i.e., (D(+/-) . C. d/D(+/-)M C

  15. Influence of acetic, citric, and lactic acids on Escherichia coli O157:H7 membrane lipid composition, verotoxin secretion, and acid resistance in simulated gastric fluid.

    PubMed

    Yuk, Hyun-Gyun; Marshall, Douglas L

    2005-04-01

    The effect of organic acid (acetic, citric, and lactic acids) adaptation at equivalent initial pH values (6.4 and 5.4) on changes in membrane lipid composition, verotoxin concentration, and acid resistance in simulated gastric fluid (pH 1.5, 37 degrees C) was determined for Escherichia coli O157:H7 ATCC 43895 (HEC) and an rpoS mutant of E. coli O157:H7 ATCC 43895 (RM, FRIK 816-3). For HEC, lactic acid-adapted (pH 5.4) cells had the greatest D-value (32.2 min) and acetic acid-adapted (pH 5.4) cells had the smallest D-value (16.6 min) in simulated gastric fluid. For RM, D-values of citric and acetic acid-adapted cells were similar to those for nonadapted cells grown at pH 7.3, but D-values increased from 13.1 to 27.9 min in lactic acid-adapted cells (from pH 7.3 to pH 5.4). For both strains, the ratio of cis-vaccenic to palmitic acids decreased for citric and lactic acid-adapted cells, but the ratio increased for acetic acid-adapted cells at pH 5.4. Organic acid-adapted cells produced less total verotoxin than did nonadapted cells at approximately 10(8) CFU/ml. Extracellular verotoxin concentration proportionally decreased with decreasing pH for both HEC and RM. Changes in membrane lipid composition, verotoxin concentration, and acid resistance in HEC and RM were dependent on both pH and organic acid. Deletion of the rpoS gene did not affect these changes but did decrease acid resistance in citric acid-adapted cells. Results indicate that decreased membrane fluidity may have caused increased acid resistance and decreased verotoxin secretion.

  16. Layered Poly(ethylene-co-vinyl acetate)/Poly(ethylene-co-vinyl alcohol) Membranes with Enhanced Water Separation Selectivity and Performance.

    PubMed

    Soto Puente, J A; Fatyeyeva, K; Chappey, C; Marais, S; Dargent, E

    2017-02-22

    A three-layered membrane based on poly(ethylene-co-vinyl acetate) (EVA) and hydrolyzed EVA-poly(ethylene-co-vinyl alcohol) (EVOH), was elaborated by the surface hydrolysis of a dense EVA membrane. Because of the chemical modifications, the three-layered EVOH/EVA/EVOH membrane was characterized by the particular microstructure (amorphous EVA and semicrystalline EVOH) and the tunable hydrophilic/hydrophobic balance. Also, these modifications led to the membrane with the selective barrier properties compared with the pure EVA and completely hydrolyzed EVOH membranes. The water barrier behavior was related to the strong hydrogen-bond interactions of water and vinyl alcohol groups, whereas the weak chemical interactions were revealed for gases (N2 and O2). Furthermore, the influence of the polymer rubbery or glassy state on the permeation kinetics was established. In the case of the three-layered membrane, the considerably high selectivity values were obtained for H2O/O2 (∼11 900) and H2O/N2 (∼48 000) at 25 °C. In addition to these highly selective properties, the three-layered structure does not present delamination features due to its elaboration procedure. Thus, these new layered membranes are very promising as selective materials for the water and gas separation and can be potentially used in food packaging or for the gas dehydration.

  17. Conjugation of silica nanoparticles with cellulose acetate/polyethylene glycol 300 membrane for reverse osmosis using MgSO4 solution.

    PubMed

    Sabir, Aneela; Shafiq, Muhammad; Islam, Atif; Jabeen, Faiza; Shafeeq, Amir; Ahmad, Adnan; Zahid Butt, Muhammad Taqi; Jacob, Karl I; Jamil, Tahir

    2016-01-20

    Thermally-induced phase separation (TIPS) method was used to synthesize polymer matrix (PM) membranes for reverse osmosis from cellulose acetate/polyethylene glycol (CA/PEG300) conjugated with silica nanoparticles (SNPs). Experimental data showed that the conjugation of SNPs changed the surface properties as dense and asymmetric composite structure. The results were explicitly determined by the permeability flux and salt rejection efficiency of the PM-SNPs membranes. The effect of SNPs conjugation on MgSO4 salt rejection was more significant in magnitude than on permeation flux i.e. 2.38 L/m(2)h. FTIR verified that SNPs were successfully conjugated on the surface of PM membrane. DSC of PM-SNPs shows an improved Tg from 76.2 to 101.8 °C for PM and PM-S4 respectively. Thermal stability of the PM-SNPs membranes was observed by TGA which was significantly enhanced with the conjugation of SNPs. The micrographs of SEM and AFM showed the morphological changes and increase in the valley and ridges on membrane surface. Experimental data showed that the PM-S4 (0.4 wt% SNPs) membrane has maximum salt rejection capacity and was selected as an optimal membrane.

  18. Lithium dodecyl sulfate/polyacrylamide gel electrophoresis of thylakoid membranes at 4 degrees C: Characterizations of two additional chlorophyll a-protein complexes.

    PubMed

    Delepelaire, P; Chua, N H

    1979-01-01

    Lithium dodecyl sulfate/polyacrylamide gel electrophoresis of Chlamydomonas reinhardtii thylakoid membranes at room temperature gave two chlorophyll-protein complexes, CP I and CP II, as had been reported previously. However, when the electrophoresis was performed at 4 degrees C, there was an increase in the amount of chlorophyll associated with CP I and CP II, and in addition, three other chlorophyll-protein complexes appeared. Two of these complexes, designated CP III and CP IV, were characterized and found to be similar in their compositions. Each complex contains four to five molecules of chlorophyll a, one molecule of beta-carotene, and one polypeptide chain. The apoprotein of CP III is polypeptide 5 (M(r) 50,000) and that of CP IV is polypeptide 6 (M(r) 47,000); the two polypeptides are structurally unrelated. Chlorophyll-protein complexes similar to C. reinhardtii CP III and CP IV were also detected in higher plants (e.g., Pisum sativum). The apoproteins of the higher plant complexes are immunochemically related to those of the C. reinhardtii complexes, as shown by crossed immunoelectrophoresis. Absorption spectra of CP III and CP IV at -196 degrees C revealed a component at 682 nm. This observation, together with the previous results on photosystem II mutants [Chua, N.-H. & Bennoun, P. (1975) Proc. Natl. Acad. Sci. USA 72, 2175-2179], provides indirect evidence that CP III and CP IV may be involved in the primary photochemistry of photosystem II.

  19. Electrophoresis-Enhanced Detection of Deoxyribonucleic Acids on a Membrane-Based Lateral Flow Strip Using Avian Influenza H5 Genetic Sequence as the Model

    PubMed Central

    Wu, Jui-Chuang; Chen, Chih-Hung; Fu, Ja-Wei; Yang, Huan-Ching

    2014-01-01

    This study reports a simple strategy to detect a deoxyribonucleic acid (DNA) on a membrane-based lateral flow (MBLF) strip without tedious gel preparation, gel electrophoresis, and EtBr-staining processes. The method also enhances the detection signal of the genetic sample. A direct electric field was applied over two ends of the MBLF strips to induce an electrophoresis of DNAs through the strips. The signal enhancement was demonstrated by the detection of the H5 subtype of avian influenza virus (H5 AIV). This approach showed an excellent selectivity of H5 AIV from other two control species, Arabidopsis thaliana and human PSMA5. It also showed an effective signal repeatability and sensitivity over a series of analyte concentrations. Its detection limit could be enhanced, from 40 ng to 0.1 ng by applying 12 V. The nano-gold particles for the color development were labeled on the capture antibody, and UV-VIS and TEM were used to check if the labeling was successful. This detection strategy could be further developed to apply on the detection of drug-allergic genes at clinics or detection of infectious substances at incident sites by a simple manipulation with an aid of a mini-PCR machine and auxiliary kits. PMID:24603637

  20. STABILITY OF MFI ZEOLITE-FILLED PDMS MEMBRANES DURING PERVAPORATIVE ETHANOL RECOVERY FROM AQUEOUS MIXTURES CONTAINING ACETIC ACID

    EPA Science Inventory

    Pervaporation is a potential process for recovering bioethanol produced from biomass fermentation. Fermentation broths contain ethanol, water, and a variety of other compounds, often including carboxylic acids. The effects of acetic acid on long-term pervaporation of aqueous et...

  1. Versatile microanalytical system with porous polypropylene capillary membrane for calibration gas generation and trace gaseous pollutants sampling applied to the analysis of formaldehyde, formic acid, acetic acid and ammonia in outdoor air.

    PubMed

    Coelho, Lúcia H G; Melchert, Wanessa R; Rocha, Flavio R; Rocha, Fábio R P; Gutz, Ivano G R

    2010-11-15

    The analytical determination of atmospheric pollutants still presents challenges due to the low-level concentrations (frequently in the μg m(-3) range) and their variations with sampling site and time. In this work, a capillary membrane diffusion scrubber (CMDS) was scaled down to match with capillary electrophoresis (CE), a quick separation technique that requires nothing more than some nanoliters of sample and, when combined with capacitively coupled contactless conductometric detection (C(4)D), is particularly favorable for ionic species that do not absorb in the UV-vis region, like the target analytes formaldehyde, formic acid, acetic acid and ammonium. The CMDS was coaxially assembled inside a PTFE tube and fed with acceptor phase (deionized water for species with a high Henry's constant such as formaldehyde and carboxylic acids, or acidic solution for ammonia sampling with equilibrium displacement to the non-volatile ammonium ion) at a low flow rate (8.3 nL s(-1)), while the sample was aspirated through the annular gap of the concentric tubes at 2.5 mL s(-1). A second unit, in all similar to the CMDS, was operated as a capillary membrane diffusion emitter (CMDE), generating a gas flow with know concentrations of ammonia for the evaluation of the CMDS. The fluids of the system were driven with inexpensive aquarium air pumps, and the collected samples were stored in vials cooled by a Peltier element. Complete protocols were developed for the analysis, in air, of NH(3), CH(3)COOH, HCOOH and, with a derivatization setup, CH(2)O, by associating the CMDS collection with the determination by CE-C(4)D. The ammonia concentrations obtained by electrophoresis were checked against the reference spectrophotometric method based on Berthelot's reaction. Sensitivity enhancements of this reference method were achieved by using a modified Berthelot reaction, solenoid micro-pumps for liquid propulsion and a long optical path cell based on a liquid core waveguide (LCW). All

  2. Gypsum (CaSO4·2H2O) Scaling on Polybenzimidazole and Cellulose Acetate Hollow Fiber Membranes under Forward Osmosis

    PubMed Central

    Chen, Si Cong; Su, Jincai; Fu, Feng-Jiang; Mi, Baoxia; Chung, Tai-Shung

    2013-01-01

    We have examined the gypsum (CaSO4·2H2O) scaling phenomena on membranes with different physicochemical properties in forward osmosis (FO) processes. Three hollow fiber membranes made of (1) cellulose acetate (CA), (2) polybenzimidazole (PBI)/polyethersulfone (PES) and (3) PBI-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) were studied. For the first time in FO processes, we have found that surface ionic interactions dominate gypsum scaling on the membrane surface. A 70% flux reduction was observed on negatively charged CA and PBI membrane surfaces, due to strong attractive forces. The PBI membrane surface also showed a slightly positive charge at a low pH value of 3 and exhibited a 30% flux reduction. The atomic force microscopy (AFM) force measurements confirmed a strong repulsive force between gypsum and PBI at a pH value of 3. The newly developed PBI-POSS/PAN membrane had ridge morphology and a contact angle of 51.42° ± 14.85° after the addition of hydrophilic POSS nanoparticles and 3 min thermal treatment at 95 °C. Minimal scaling and an only 1.3% flux reduction were observed at a pH value of 3. Such a ridge structure may reduce scaling by not providing a locally flat surface to the crystallite at a pH value of 3; thus, gypsum would be easily washed away from the surface. PMID:24957062

  3. Gypsum (CaSO4·2H2O) Scaling on Polybenzimidazole and Cellulose Acetate Hollow Fiber Membranes under Forward Osmosis.

    PubMed

    Chen, Si Cong; Su, Jincai; Fu, Feng-Jiang; Mi, Baoxia; Chung, Tai-Shung

    2013-11-08

    We have examined the gypsum (CaSO4·2H2O) scaling phenomena on membranes with different physicochemical properties in forward osmosis (FO) processes. Three hollow fiber membranes made of (1) cellulose acetate (CA), (2) polybenzimidazole (PBI)/polyethersulfone (PES) and (3) PBI-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) were studied. For the first time in FO processes, we have found that surface ionic interactions dominate gypsum scaling on the membrane surface. A 70% flux reduction was observed on negatively charged CA and PBI membrane surfaces, due to strong attractive forces. The PBI membrane surface also showed a slightly positive charge at a low pH value of 3 and exhibited a 30% flux reduction. The atomic force microscopy (AFM) force measurements confirmed a strong repulsive force between gypsum and PBI at a pH value of 3. The newly developed PBI-POSS/PAN membrane had ridge morphology and a contact angle of 51.42° ± 14.85° after the addition of hydrophilic POSS nanoparticles and 3 min thermal treatment at 95 °C. Minimal scaling and an only 1.3% flux reduction were observed at a pH value of 3. Such a ridge structure may reduce scaling by not providing a locally flat surface to the crystallite at a pH value of 3; thus, gypsum would be easily washed away from the surface.

  4. Effects of clary sage oil and its main components, linalool and linalyl acetate, on the plasma membrane of Candida albicans: an in vivo EPR study.

    PubMed

    Blaskó, Ágnes; Gazdag, Zoltán; Gróf, Pál; Máté, Gábor; Sárosi, Szilvia; Krisch, Judit; Vágvölgyi, Csaba; Makszin, Lilla; Pesti, Miklós

    2017-02-01

    The effects of clary sage (Salvia sclarea L.) oil (CS-oil), and its two main components, linalool (Lol) and linalyl acetate (LA), on cells of the eukaryotic human pathogen yeast Candida albicans were studied. Dynamic and thermodynamic properties of the plasma membrane were investigated by electron paramagnetic resonance (EPR) spectroscopy, with 5-doxylstearic acid (5-SASL) and 16-SASL as spin labels. The monitoring of the head group regions with 5-SASL revealed break-point frequency decrease in a temperature dependent manner of the plasma membrane between 9.55 and 13.15 °C in untreated, in CS-oil-, Lol- and LA-treated membranes. The results suggest a significant increase in fluidity of the treated plasma membranes close to the head groups. Comparison of the results observed with the two spin labels demonstrated that CS-oil and LA induced an increased level of fluidization at both depths of the plasma membrane. Whereas Lol treatment induced a less (1 %) ordered bilayer organization in the superficial regions and an increased (10 %) order of the membrane leaflet in deeper layers. Acute toxicity tests and EPR results indicated that both the apoptotic and the effects exerted on the plasma membrane fluidity depended on the composition and chemical structure of the examined materials. In comparison with the control, treatment with CS-oil, Lol or LA induced 13.0, 12.3 and 26.4 % loss respectively, of the metabolites absorbing at 260 nm, as a biological consequence of the plasma membrane fluidizing effects. Our results confirmed that clary sage oil causes plasma membrane perturbations which leads to cell apoptosis process.

  5. Phase transfer membrane supported liquid-liquid-liquid microextraction combined with large volume sample injection capillary electrophoresis-ultraviolet detection for the speciation of inorganic and organic mercury.

    PubMed

    Li, Pingjing; Zhang, Xing; Hu, Bin

    2011-12-30

    In this paper, a novel sample pretreatment technique termed phase transfer based liquid-liquid-liquid microextraction (PT-LLLME) was proposed for the simultaneous extraction of inorganic and organic mercury species. In PT-LLLME, an intermediate solvent (acetonitrile) was added into the donor phase to improve the contacting between target mercury species and complexing reagent. Meanwhile, a membrane supported (MS)-LLLME unit was designed to realize the PT-LLLME procedure. By using nylon membrane as supporting carrier, larger than 50 μL of acceptor solution could be hung up. Following PT/MS-LLLME, the acceptor solutions were directly analyzed by large volume sample stacking capillary electrophoresis/ultraviolet detection (LVSS-CE/UV). Accordingly, a new method of PT/MS-LLLME combined with LVSS-CE/UV was developed for the simultaneous speciation of inorganic and organic mercury species. Parameters affecting the extraction efficiency of PT/MS-LLLME were investigated in details. Under the optimized conditions, enrichment factors (EFs) ranging from 160- to 478-fold were obtained for the extraction of target mercury species by PT/MS-LLLME. By combining PT/MS-LLLME with LVSS-CE/UV, EFs were magnified up to 12,138-fold and the limits of detection (at a signal-to-noise ratio of 3) were at sub ppb level. The established approach of PT/MS-LLLME-LVSS-CE/UV was successfully applied to simultaneous determination of inorganic and organic mercury species in biological samples and environmental water samples.

  6. Synthesis and Characterisation of ETS-10/Acetate-based Ionic Liquid/Chitosan Mixed Matrix Membranes for CO2/N2 Permeation.

    PubMed

    Casado-Coterillo, Clara; Del Mar López-Guerrero, María; Irabien, Angel

    2014-06-19

    Mixed matrix membranes (MMMs) were prepared by incorporating organic surfactant-free hydrothermally synthesised ETS-10 and 1-ethyl-3-methylimidazolium acetate ionic liquid (IL) to chitosan (CS) polymer matrix. The membrane material characteristics and permselectivity performance of the two-component membranes were compared with the three-component membrane and the pure CS membrane. The addition of IL increased CO2 solubility of the polymer, and, thus, the CO2 affinity was maintained for the MMMs, which can be correlated with the crystallinity, measured by FT-IR, and void fraction calculations from differences between theoretical and experimental densities. The mechanical resistance was enhanced by the ETS-10 nanoparticles, and flexibility decreased in the two-component ETS-10/CS MMMs, but the flexibility imparted by the IL remained in three-component ETS-10/IL/CS MMMs. The results of this work provide insight into another way of facing the adhesion challenge in MMMs and obtain CO2 selective MMMs from renewable or green chemistry materials.

  7. Synthesis and Characterisation of ETS-10/Acetate-based Ionic Liquid/Chitosan Mixed Matrix Membranes for CO2/N2 Permeation

    PubMed Central

    Casado-Coterillo, Clara; López-Guerrero, María del Mar; Irabien, Ángel

    2014-01-01

    Mixed matrix membranes (MMMs) were prepared by incorporating organic surfactant-free hydrothermally synthesised ETS-10 and 1-ethyl-3-methylimidazolium acetate ionic liquid (IL) to chitosan (CS) polymer matrix. The membrane material characteristics and permselectivity performance of the two-component membranes were compared with the three-component membrane and the pure CS membrane. The addition of IL increased CO2 solubility of the polymer, and, thus, the CO2 affinity was maintained for the MMMs, which can be correlated with the crystallinity, measured by FT-IR, and void fraction calculations from differences between theoretical and experimental densities. The mechanical resistance was enhanced by the ETS-10 nanoparticles, and flexibility decreased in the two-component ETS-10/CS MMMs, but the flexibility imparted by the IL remained in three-component ETS-10/IL/CS MMMs. The results of this work provide insight into another way of facing the adhesion challenge in MMMs and obtain CO2 selective MMMs from renewable or green chemistry materials. PMID:24957178

  8. Analysis of electrophoresis performance

    NASA Technical Reports Server (NTRS)

    Roberts, G. O.

    1984-01-01

    The SAMPLE computer code models electrophoresis separation in a wide range of conditions. Results are included for steady three dimensional continuous flow electrophoresis (CFE), time dependent gel and acetate film experiments in one or two dimensions and isoelectric focusing in one dimension. The code evolves N two dimensional radical concentration distributions in time, or distance down a CFE chamber. For each time or distance increment, there are six stages, successively obtaining the pH distribution, the corresponding degrees of ionization for each radical, the conductivity, the electric field and current distribution, and the flux components in each direction for each separate radical. The final stage is to update the radical concentrations. The model formulation for ion motion in an electric field ignores activity effects, and is valid only for low concentrations; for larger concentrations the conductivity is, therefore, also invalid.

  9. Cell adhesion to proteins separated by lithium dodecyl sulfate-polyacrylamide gel electrophoresis and blotted onto a polyvinylidene difluoride membrane: a new cell-blotting technique.

    PubMed

    Seshi, B

    1994-12-02

    Cell blotting, although conceptually simple, has failed to achieve wide practical application. Described here is a new cell-blotting technique which involves cell adhesion to protein bands after separation by lithium dodecyl sulfate-polyacrylamide gel electrophoresis (LDS-PAGE) and blotting onto polyvinylidene difluoride (PVDF) membrane at 4 degrees C. Cell bands adherent on PVDF are detected using hematoxylin, or propidium iodide (PI) staining followed by viewing under ultraviolet (UV) light. The technique allows quick microscopic visualization of adherent cells composing the bands, without requiring clearing of the membrane. Representative cell adhesion proteins from different sources, i.e., plant lectins (e.g., phytohemagglutinin, PHA; concanavalin A, ConA; and wheat germ agglutinin, WGA); extracellular matrix (ECM) proteins; and integral membrane proteins (e.g., recombinant soluble vascular cell adhesion molecule-1, rs VCAM-1) were tested for cell binding by the new cell-blotting technique using human lymphoid progenitor (NALM-6) and myeloid progenitor (KG1a) cell lines. Cell adhesion proteins retained their adhesion function in all cases tested. Specificity of cell binding on PVDF blot was demonstrated by inhibition of cell adhesion to WGA protein bands using an appropriate sugar, i.e., N-acetyl D-glucosamine. The cell blotting assay was comparable in sensitivity to Coomassie blue staining of protein bands. The ability to conduct protein extraction, separation and blotting at low temperature avoids thermal denaturation, thereby preserving the adhesion properties of the proteins. The electrophoretic/blotting system has unique detergent removal/protein renaturation properties and the ability to preserve functionally active adhesion protein complexes. The cell-blotting technique described is sufficiently robust for routine application in the investigation of novel cell adhesion proteins.

  10. Analysis of diazinon pesticide using potentiometric biosensor based on enzyme immobilized cellulose acetate membrane in gold electrode

    NASA Astrophysics Data System (ADS)

    Mashuni; Ramadhan, L. O. A. N.; Jahiding, M.; Herniati

    2016-02-01

    Biosensor for analysis of diazinon pesticide using Potentiometric transducer has been developed. The basic element of this biosensor was a gold electrode modified with an immobilized acetylcholinesterase enzyme layer formed by entrapment with glutaraldehyde crosslinked-cellulose acetate. The aim of the research is to determine the composition of glutaraldehyde crosslinked-cellulose acetate in the gold electrode which provide optimum performance of biosensors of diazinon pesticide analysis on characterization include a range of working concentration, sensitivity, and detection limit. The results showed the composition of the cellulose acetate 15% and glutaraldehyde 25% that obtain optimum performance in the measurement of diazinon pesticide with a range of working concentration of 10-6 ppm to 1 ppm, the value of sensitivity 20.275 mV/decade and detection limit 10-6 ppm. The use of cellulose acetate provides highly sensitive devices allowing the efficient analysis of pesticides. The response time of electrode is on the measurement of pesticide diazinon with concentration variation of 10-6 ppm to 1 ppm with response time is about 5 minutes.

  11. Micromanipulation of adhesion of phorbol 12-myristate-13-acetate-stimulated T lymphocytes to planar membranes containing intercellular adhesion molecule-1.

    PubMed Central

    Tözeren, A; Mackie, L H; Lawrence, M B; Chan, P Y; Dustin, M L; Springer, T A

    1992-01-01

    This paper presents an analytical and experimental methodology to determine the physical strength of cell adhesion to a planar membrane containing one set of adhesion molecules. In particular, the T lymphocyte adhesion due to the interaction of the lymphocyte function associated molecule 1 on the surface of the cell, with its counter-receptor, intercellular adhesion molecule-1 (ICAM-1), on the planar membrane, was investigated. A micromanipulation method and mathematical analysis of cell deformation were used to determine (a) the area of conjugation between the cell and the substrate and (b) the energy that must be supplied to detach a unit area of the cell membrane from its substrate. T lymphocytes stimulated with phorbol 12-myristate-13-acetate (PMA) conjugated strongly with the planar membrane containing purified ICAM-1. The T lymphocytes attached to the planar membrane deviated occasionally from their round configuration by extending pseudopods but without changing the size of the contact area. These adherent cells were dramatically deformed and then detached when pulled away from the planar membrane by a micropipette. Detachment occurred by a gradual decrease in the radius of the contact area. The physical strength of adhesion between a PMA-stimulated T lymphocyte and a planar membrane containing 1,000 ICAM-1 molecules/micron 2 was comparable to the strength of adhesion between a cytotoxic T cell and its target cell. The comparison of the adhesive energy density, measured at constant cell shape, with the model predictions suggests that the physical strength of cell adhesion may increase significantly when the adhesion bonds in the contact area are immobilized by the actin cytoskeleton. Images FIGURE 2 FIGURE 4 FIGURE 5 FIGURE 8 FIGURE 9 PMID:1358239

  12. Membrane filtration of Sudan orange G on a cellulose acetate membrane filter for separation-preconcentration and spectrophotometric determination in water, chili powder, chili sauce and tomato sauce samples.

    PubMed

    ALOthman, Zeid A; Unsal, Yunus E; Habila, Mohamed; Shabaka, Azza; Tuzen, Mustafa; Soylak, Mustafa

    2012-08-01

    A simple membrane filtration procedure for separation-enrichment of Sudan orange G is presented. The method is based on the adsorption of Sudan orange G on a cellulose acetate filter and its elution from the membrane with 10 mL of ethanol. Sudan orange G in the eluent was determined by UV-visible spectrophotometry at 388 nm. The effect of analytical conditions, including pH, flow rates and eluent, sample volume, type of membrane for quantitative preconcentration and separation of Sudan orange G were examined. The influences of matrix components on Sudan orange G recoveries were studied. The preconcentration factor was 125. The detection limit was 4.9 μg L(-1). The relative standard deviation was 4.3%. The presented procedure was applied to chili powder, chili sauce, tomato sauce, powdered beverage and water samples.

  13. Separation and identification of peptides from gel-isolated membrane proteins using a microfabricated device for combined capillary electrophoresis/nanoelectrospray mass spectrometry.

    PubMed

    Li, J; Kelly, J F; Chernushevich, I; Harrison, D J; Thibault, P

    2000-02-01

    The coupling of microfabricated devices to nanoelectrospray mass spectrometers using both a triple quadrupole and a quadrupole time-of-flight mass spectrometer (QqTOF MS) is presented for the analysis of trace-level membrane proteins. Short disposable nanoelectrospray emitters were directly coupled to the chip device via a low dead volume connection. The analytical performance of this integrated device in terms of sensitivity and reproducibility was evaluated for standard peptide mixtures. A concentration detection limit ranging from 3.2 to 43.5 nM for different peptides was achieved in selected ion monitoring, thus representing a 10-fold improvement in sensitivity compared to that of microelectrospray using the same chip/mass spectrometer. Replicate injections indicated that reproducibility of migration time was typically less than 3.1% RSD whereas RSD values of 6-13% were observed on peak areas. Although complete resolution of individual components is not typically achieved for complex digests, the present chip capillary electrophoresis (chip-CE) device enabled proper sample cleanup and partial separation of multicomponent samples prior to mass spectral identification. Analyses of protein digests were typically achieved in less than 1.5 min with peak widths of 1.8-2.5 s (half-height definition) as indicated from individual reconstructed ion electropherograms. The application of this chip-CE/QqTOF MS system is further demonstrated for the identification of membrane proteins which form a subset of the Haemophilus influenzae proteome. Bands first separated by 1D-gel electrophoresis were excised and digested, and extracted tryptic peptides were loaded on the chip without any further sample cleanup or on-line adsorption preconcentration. Accurate molecular mass determination (< 5 ppm) in peptide-mapping experiments was obtained by introducing an internal standard via a postseparation channel. The analytical potential of this integrated device for the identification of

  14. Electro membrane isolation of nerve agent degradation products across a supported liquid membrane followed by capillary electrophoresis with contactless conductivity detection.

    PubMed

    Xu, Li; Hauser, Peter C; Lee, Hian Kee

    2008-12-19

    In the present study, electro membrane isolation (EMI) of four nerve agent degradation products has been successfully explored. In the procedure, a polypropylene sheet membrane folded into an envelope with an open end with its wall pores impregnated with 1-octanol was employed as the artificial supported liquid membrane (SLM). The envelope containing the extractant or aqueous acceptor phase (at pH 6.8) was immersed in the sample or donor phase (also aqueous at a pH of 6.8) for extraction. This ensured that the target analytes were fully ionized. A voltage was then applied, with the negative electrode placed in the donor phase with agitation, and the positive electrode in the acceptor phase. The ionized analytes were thus driven to migrate from the donor phase across the SLM to the acceptor phase. The factors influential to extraction: type of organic solvent, voltage, agitation speed, extraction time, pH of the donor and acceptor phase and concentration of humic acids were investigated in detail. After extraction, the acceptor phase was collected and directly injected for capillary electrophoretic (CE) analysis. Combined with capacitively coupled contactless conductivity detection (C(4)D), the direct detection of these compounds could be achieved. Moreover, large-volume sample injection was employed to further enhance the sensitivity of this method. Limits of detection (LODs) as low as ng/mL were reached for the studied analytes, with overall LOD enhancements of four orders of magnitude.

  15. In-line coupling of microextractions across polymer inclusion membranes to capillary zone electrophoresis for rapid determination of formate in blood samples.

    PubMed

    Pantůčková, Pavla; Kubáň, Pavel; Boček, Petr

    2015-08-05

    Polymer inclusion membranes (PIMs) have several important features, i.e., PIMs are dry and non-porous membranes, which can be prepared ahead of use and stored without noticeable deterioration in extraction performance. In this contribution, in-line coupling of microextractions across PIMs to a separation method for clinical purposes was demonstrated for the first time. Formate (the major metabolite in methanol poisoning) was determined in undiluted human serum and whole blood by capillary zone electrophoresis (CZE) with simultaneous capacitively coupled contactless conductivity detection (C(4)D) and UV-Vis detection. A purpose-made microextraction device with PIM was coupled to a commercial CZE instrument in order to ensure complete automation of the entire analytical procedure, i.e., of formate extraction, injection, CZE separation and quantification. PIMs for formate extractions consisted of 60% (w/w) cellulose triacetate as base polymer and 40% (w/w) Aliquat™ 336 as anion carrier. The method was characterized by good repeatability of peak areas (≤7.0%) and migration times (≤0.8%) and by good linearity of calibration curves (r(2) = 0.993-0.999). Limits of detection in various matrices ranged from 15 to 54 μM for C(4)D and from 200 to 635 μM for UV-Vis detection and were sufficiently low to clearly distinguish between endogenous and toxic levels of formate in healthy and methanol intoxicated individuals. In addition, PIMs proved that they may act as phase interfaces with excellent long-term stability since once prepared, they retained their extractions properties for, at least, two months of storage.

  16. Capillary electrophoresis.

    PubMed

    Compton, S W; Brownlee, R G

    1988-05-01

    While capillary electrophoresis, or historically related techniques, have been used for over a century, and recognition of the value of this separation methodology has certainly grown rapidly in the past few years, the technique has generally been used by analytical chemists, particularly in Europe and Japan, and small groups of researchers in the United States. Many of the basic instrumentation problems have been solved only relatively recently, and researchers using capillary electrophoresis are now turning their attention to studying specific applications which demonstrate the potential versatility of this electrophoretic technique. The appearance of standardized commercial instrumentation is imminent. With the availability of such technology, capillary electrophoresis will no longer be an academic curiosity, but rather a tool with the potential for routine separations of diverse samples of interest to analyst, researcher, and clinician.

  17. Electrophoresis technology

    NASA Technical Reports Server (NTRS)

    Snyder, R. S.

    1985-01-01

    A new high resolution apparatus designed for space was built as a laboratory prototype. Using a moving wall with a low zeta potential coating, the major sources of flow distortion for an electrophoretic sample stream are removed. Highly resolved fractions, however, will only be produced in space because of the sensitivity of this chamber to buoyancy-induced convection in the laboratory. The second and third flights of the McDonnell Douglas Astronautics Corporation continuous flow electrophoresis system carried samples developed at MSFC intended to evaluate the broad capabilities of free flow electrophoresis in a reduced gravity environment. Biological model materials, hemoglobin and polystyrene latex microspheres, were selected because of their past use as electrophoresis standards and as visible markers for fluid flow due to electroosmosis, spacecraft acceleration or other factors. The dependence of the separation resolution on the properties of the sample and its suspension solution was assessed.

  18. Parallel Characterization of Anaerobic Toluene- and Ethylbenzene-Degrading Microbial Consortia by PCR-Denaturing Gradient Gel Electrophoresis, RNA-DNA Membrane Hybridization, and DNA Microarray Technology

    PubMed Central

    Koizumi, Yoshikazu; Kelly, John J.; Nakagawa, Tatsunori; Urakawa, Hidetoshi; El-Fantroussi, Saïd; Al-Muzaini, Saleh; Fukui, Manabu; Urushigawa, Yoshikuni; Stahl, David A.

    2002-01-01

    A mesophilic toluene-degrading consortium (TDC) and an ethylbenzene-degrading consortium (EDC) were established under sulfate-reducing conditions. These consortia were first characterized by denaturing gradient gel electrophoresis (DGGE) fingerprinting of PCR-amplified 16S rRNA gene fragments, followed by sequencing. The sequences of the major bands (T-1 and E-2) belonging to TDC and EDC, respectively, were affiliated with the family Desulfobacteriaceae. Another major band from EDC (E-1) was related to an uncultured non-sulfate-reducing soil bacterium. Oligonucleotide probes specific for the 16S rRNAs of target organisms corresponding to T-1, E-1, and E-2 were designed, and hybridization conditions were optimized for two analytical formats, membrane and DNA microarray hybridization. Both formats were used to characterize the TDC and EDC, and the results of both were consistent with DGGE analysis. In order to assess the utility of the microarray format for analysis of environmental samples, oil-contaminated sediments from the coast of Kuwait were analyzed. The DNA microarray successfully detected bacterial nucleic acids from these samples, but probes targeting specific groups of sulfate-reducing bacteria did not give positive signals. The results of this study demonstrate the limitations and the potential utility of DNA microarrays for microbial community analysis. PMID:12088997

  19. Parallel characterization of anaerobic toluene- and ethylbenzene-degrading microbial consortia by PCR-denaturing gradient gel electrophoresis, RNA-DNA membrane hybridization, and DNA microarray technology

    NASA Technical Reports Server (NTRS)

    Koizumi, Yoshikazu; Kelly, John J.; Nakagawa, Tatsunori; Urakawa, Hidetoshi; El-Fantroussi, Said; Al-Muzaini, Saleh; Fukui, Manabu; Urushigawa, Yoshikuni; Stahl, David A.

    2002-01-01

    A mesophilic toluene-degrading consortium (TDC) and an ethylbenzene-degrading consortium (EDC) were established under sulfate-reducing conditions. These consortia were first characterized by denaturing gradient gel electrophoresis (DGGE) fingerprinting of PCR-amplified 16S rRNA gene fragments, followed by sequencing. The sequences of the major bands (T-1 and E-2) belonging to TDC and EDC, respectively, were affiliated with the family Desulfobacteriaceae. Another major band from EDC (E-1) was related to an uncultured non-sulfate-reducing soil bacterium. Oligonucleotide probes specific for the 16S rRNAs of target organisms corresponding to T-1, E-1, and E-2 were designed, and hybridization conditions were optimized for two analytical formats, membrane and DNA microarray hybridization. Both formats were used to characterize the TDC and EDC, and the results of both were consistent with DGGE analysis. In order to assess the utility of the microarray format for analysis of environmental samples, oil-contaminated sediments from the coast of Kuwait were analyzed. The DNA microarray successfully detected bacterial nucleic acids from these samples, but probes targeting specific groups of sulfate-reducing bacteria did not give positive signals. The results of this study demonstrate the limitations and the potential utility of DNA microarrays for microbial community analysis.

  20. Simulating Electrophoresis.

    ERIC Educational Resources Information Center

    Moertel, Cheryl; Frutiger, Bruce

    1996-01-01

    Describes a DNA fingerprinting simulation that uses vegetable food coloring and plastic food containers instead of DNA and expensive gel electrophoresis chambers. Allows students to decipher unknown combinations of dyes in a method similar to that used to decipher samples of DNA in DNA fingerprint techniques. (JRH)

  1. Separation of Cu2+, Cd2+ and Cr3+ in a Mixture Solution Using a Novel Carrier Poly(Methyl Thiazoleethyl Eugenoxy Acetate) with BLM (Bulk Liquid Membrane)

    NASA Astrophysics Data System (ADS)

    Djunaidi, M. C.; Khabibi; Ulumudin, I.

    2017-02-01

    The separation process using a novel carrier polyeugenol has active groups N and S has been done with the technique BLM. Polyeugenol has groups active N and S was synthesized from eugenol which is then polymerized into polyeugenol. This polymeric compounds was then acidified become acidic poly (eugenoksi acetate). After the acid formed, then the synthesis was continued by add 4-methyl-5-tiazoleetanol to form esters poly (methyl thiazole eugenoxy ethyl acetate) (PMTEEA). The result of the synthesis was analyzed by FTIR and 1H NMR. This polyester product synthesis was applied as a carrier for separating metal ions Cu2+, Cd2+ and Cr3+ with variations in feed phase pH = 5 and pH = 7 in the membrane of chloroform using techniques BLM. Receiving phase after 24 hours was analyzed by AAS. In variations of feed pH = 5 ions was obtained 66.21% Cd2+, 28.83% Cu2+ and 10.92% of Cr3+, at pH = 7 was obtained 70.77% Cd2+, 30.14% Cu2+, and 3.72% of Cr3+.

  2. STABILITY OF MFI ZEOLITE-FILLED PDMS MEMBRANES DURING PERVAPORATIVE ETHANOL RECOVERY FROM AQUEOUS MIXTURES CONTAINING ACETIC ACID

    EPA Science Inventory

    Pervaporation is potentially a cost-effective means of recovering biofuels, such as ethanol, from biomass fermentation broths for small- to medium-scale applications (~2 - 20 million liters per year). Hydrophobic zeolite-filled polydimethylsiloxane (PDMS) membranes have been sho...

  3. Flecainide acetate acetic acid solvates.

    PubMed

    Veldre, Kaspars; Actiņs, Andris; Eglite, Zane

    2011-02-01

    Flecainide acetate forms acetic acid solvates with 0.5 and 2 acetic acid molecules. Powder X-ray diffraction, differential thermal analysis/thermogravimetric, infrared, and potentiometric titration were used to determine the composition of solvates. Flecainide acetate hemisolvate with acetic acid decomposes to form a new crystalline form of flecainide acetate. This form is less stable than the already known polymorphic form at all temperatures, and it is formed due to kinetic reasons. Both flecainide acetate nonsolvated and flecainide acetate hemisolvate forms crystallize in monoclinic crystals, but flecainide triacetate forms triclinic crystals. Solvate formation was not observed when flecainide base was treated with formic acid, propanoic acid, and butanoic acid. Only nonsolvated flecainide salts were obtained in these experiments.

  4. Membrane-bound sugar alcohol dehydrogenase in acetic acid bacteria catalyzes L-ribulose formation and NAD-dependent ribitol dehydrogenase is independent of the oxidative fermentation.

    PubMed

    Adachi, O; Fujii, Y; Ano, Y; Moonmangmee, D; Toyama, H; Shinagawa, E; Theeragool, G; Lotong, N; Matsushita, K

    2001-01-01

    To identify the enzyme responsible for pentitol oxidation by acetic acid bacteria, two different ribitol oxidizing enzymes, one in the cytosolic fraction of NAD(P)-dependent and the other in the membrane fraction of NAD(P)-independent enzymes, were examined with respect to oxidative fermentation. The cytoplasmic NAD-dependent ribitol dehydrogenase (EC 1.1.1.56) was crystallized from Gluconobacter suboxydans IFO 12528 and found to be an enzyme having 100 kDa of molecular mass and 5 s as the sedimentation constant, composed of four identical subunits of 25 kDa. The enzyme catalyzed a shuttle reversible oxidoreduction between ribitol and D-ribulose in the presence of NAD and NADH, respectively. Xylitol and L-arabitol were well oxidized by the enzyme with reaction rates comparable to ribitol oxidation. D-Ribulose, L-ribulose, and L-xylulose were well reduced by the enzyme in the presence of NADH as cosubstrates. The optimum pH of pentitol oxidation was found at alkaline pH such as 9.5-10.5 and ketopentose reduction was found at pH 6.0. NAD-Dependent ribitol dehydrogenase seemed to be specific to oxidoreduction between pentitols and ketopentoses and D-sorbitol and D-mannitol were not oxidized by this enzyme. However, no D-ribulose accumulation was observed outside the cells during the growth of the organism on ribitol. L-Ribulose was accumulated in the culture medium instead, as the direct oxidation product catalyzed by a membrane-bound NAD(P)-independent ribitol dehydrogenase. Thus, the physiological role of NAD-dependent ribitol dehydrogenase was accounted to catalyze ribitol oxidation to D-ribulose in cytoplasm, taking D-ribulose to the pentose phosphate pathway after being phosphorylated. L-Ribulose outside the cells would be incorporated into the cytoplasm in several ways when need for carbon and energy sources made it necessary to use L-ribulose for their survival. From a series of simple experiments, membrane-bound sugar alcohol dehydrogenase was concluded to be

  5. Effect of K+ and Ca2+ on the indole-3-acetic acid- and fusicoccin-induced growth and membrane potential in maize coleoptile cells

    PubMed Central

    Siemieniuk, Agnieszka; Karcz, Waldemar

    2015-01-01

    The role of potassium (K+) and calcium (Ca2+) in the regulation of plant growth and development is complex and needs a diverse range of physiological studies. Both elements are essential for satisfactory crop production. Here, the effects of K+ and Ca2+ ions on endogenous growth and growth in the presence of either indole-3-acetic acid (IAA) or fusicoccin (FC) were studied in maize (Zea mays) coleoptiles. Membrane potentials of coleoptile parenchymal cells, incubated in media containing IAA, FC and different concentrations of K+ and Ca2+, were also determined. Growth experiments have shown that in the absence of K+ in the incubation medium, both endogenous and IAA- or FC-induced growth were significantly inhibited by 0.1 and 1 mM Ca2+, respectively, while in the presence of 1 mM K+ they were inhibited only by 1 mM Ca2+. At 10 mM K+, endogenous growth and growth induced by either IAA or FC did not depend on Ca2+ concentration. TEA-Cl, a potassium channel blocker, added 1 h before IAA or FC, caused a reduction of growth by 59 or 45 %, respectively. In contrast to TEA-Cl, verapamil, the Ca2+ channel blocker, did not affect IAA- and FC-induced growth. It was also found that in parenchymal cells of maize coleoptile segments, membrane potential (Em) was strongly affected by the medium K+, independently of Ca2+. However, lack of Ca2+ in the incubation medium significantly reduced the IAA- and FC-induced membrane potential hyperpolarization. TEA-Cl applied to the control medium in the same way as in growth experiments caused Em hyperpolarization synergistic with hyperpolarization produced by IAA or FC. Verapamil did not change either the Em of parenchymal cells incubated in the control medium or the IAA- and FC-induced membrane hyperpolarization. The data presented here have been discussed considering the role of K+ uptake channels in regulation of plant cell growth. PMID:26134122

  6. Mesoxalaldehyde acetals

    SciTech Connect

    Gordeeva, G.N.; Kalashnikov, S.M.; Popov, Yu.N.; Kruglov, E.A.; Imashev, U.B.

    1987-11-10

    The treatment of methylglyoxal acetals by alkyl nitrites in the presence of the corresponding aliphatic alcohols and hydrochloric acid leads to the formation of linear mesoxalaldehyde acetals, whose structure was established by NMR spectroscopy and mass spectrometry. The major pathways for the decomposition of these molecules upon electron impact were established.

  7. Triolein embedded cellulose acetate membrane as a tool to evaluate sequestration of PAHs in lake sediment core at large temporal scale.

    PubMed

    Tao, Yuqiang; Xue, Bin; Yao, Shuchun; Deng, Jiancai; Gui, Zhifan

    2012-04-03

    Although numerous studies have addressed sequestration of hydrophobic organic compounds (HOCs) in laboratory, little attention has been paid to its evaluation method in field at large temporal scale. A biomimetic tool, triolein embedded cellulose acetate membrane (TECAM), was therefore tested to evaluate sequestration of six PAHs with various hydrophobicity in a well-dated sediment core sampled from Nanyi Lake, China. Properties of sediment organic matter (OM) varying with aging time dominated the sequestration of PAHs in the sediment core. TECAM-sediment accumulation factors (MSAFs) of the PAHs declined with aging time, and significantly correlated with the corresponding biota-sediment accumulation factors (BSAFs) for gastropod (Bellamya aeruginosa) simultaneously incubated in the same sediment slices. Sequestration rates of the PAHs in the sediment core evaluated by TECAM were much lower than those obtained from laboratory study. The relationship between relative availability for TECAM (MSAF(t)/MSAF(0)) and aging time followed the first order exponential decay model. MSAF(t)/MSAF(0) was well-related to the minor changes of the properties of OM varying with aging time. Compared with chemical extraction, sequestration reflected by TECAM was much closer to that by B. aeruginosa. In contrast to B. aeruginosa, TECAM could avoid metabolism and the influences from feeding and other behaviors of organisms, and it is much easier to deploy and ready in laboratory. Hence TECAM provides an effective and convenient way to study sequestration of PAHs and probably other HOCs in field at large temporal scale.

  8. Fluid flow electrophoresis in space

    NASA Technical Reports Server (NTRS)

    Griffin, R. N.

    1975-01-01

    Four areas relating to free-flow electrophoresis in space were investigated. The first was the degree of improvement over earthbound operations that might be expected. The second area of investigation covered the problems in developing a flowing buffer electrophoresis apparatus. The third area of investigation was the problem of testing on the ground equipment designed for use in space. The fourth area of investigation was the improvement to be expected in space for purification of biologicals. The results of some ground-based experiments are described. Other studies included cooling requirements in space, fluid sealing techniques, and measurement of voltage drop across membranes.

  9. Electrophoresis. [in microgravity environment

    NASA Technical Reports Server (NTRS)

    Bier, M.

    1977-01-01

    Ground-based techniques for electrophoresis take account of the need either to circumvent the effects of gravity to prevent convection, or to use gravity for fluid stabilization through artificial density gradients. The microgravity environments of orbiting spacecraft provides a new alternative for electrophoresis by avoiding the need for either of these two approaches. The paper presents some theoretical considerations concerning electrophoresis, examines certain experimental techniques (zone and high density gel electrophoresis, isoelectric focusing and isotachophoresis), and examines the electrophoresis of living cells.

  10. Electrophoresis device

    NASA Technical Reports Server (NTRS)

    Rhodes, P. H.; Snyder, R. S. (Inventor)

    1982-01-01

    A device for separating cellular particles of a sample substance into fractionated streams of different cellular species includes a casing having a distribution chamber, a separation chamber, and a collection chamber. The electrode chambers are separated from the separation chamber interior by means of passages such that flow variations and membrane variations around the slotted portion of the electrode chamber do not enduce flow perturbations into the laminar buffer curtain flowing in the separation chamber. The cellular particles of the sample are separated under the influence of the electrical field and the separation chamber into streams of different cellular species. The streams of separated cells enter a partition array in the collection chamber where they are fractionated and collected.

  11. Thallium acetate

    Integrated Risk Information System (IRIS)

    Jump to main content . Integrated Risk Information System Recent Additions | Contact Us Search : All EPA IRIS • You are here : EPA Home • Research • Environmental Assessment • IRIS • IRIS Summaries Redirect Page As of September 30 , 2009 , the assessment summary for Thallium acetate is included in t

  12. Phenylmercuric acetate

    Integrated Risk Information System (IRIS)

    Phenylmercuric acetate ; CASRN 62 - 38 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinog

  13. Ethyl acetate

    Integrated Risk Information System (IRIS)

    Ethyl acetate ; CASRN 141 - 78 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Eff

  14. Ammonium acetate

    Integrated Risk Information System (IRIS)

    Ammonium acetate ; CASRN 631 - 61 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  15. Vinyl acetate

    Integrated Risk Information System (IRIS)

    Vinyl acetate ; CASRN 108 - 05 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Eff

  16. The Cutting Edge of Affinity Electrophoresis Technology

    PubMed Central

    Kinoshita, Eiji; Kinoshita-Kikuta, Emiko; Koike, Tohru

    2015-01-01

    Affinity electrophoresis is an important technique that is widely used to separate and analyze biomolecules in the fields of biology and medicine. Both quantitative and qualitative information can be gained through affinity electrophoresis. Affinity electrophoresis can be applied through a variety of strategies, such as mobility shift electrophoresis, charge shift electrophoresis or capillary affinity electrophoresis. These strategies are based on changes in the electrophoretic patterns of biological macromolecules that result from interactions or complex-formation processes that induce changes in the size or total charge of the molecules. Nucleic acid fragments can be characterized through their affinity to other molecules, for example transcriptional factor proteins. Hydrophobic membrane proteins can be identified by means of a shift in the mobility induced by a charged detergent. The various strategies have also been used in the estimation of association/disassociation constants. Some of these strategies have similarities to affinity chromatography, in that they use a probe or ligand immobilized on a supported matrix for electrophoresis. Such methods have recently contributed to profiling of major posttranslational modifications of proteins, such as glycosylation or phosphorylation. Here, we describe advances in analytical techniques involving affinity electrophoresis that have appeared during the last five years. PMID:28248262

  17. Kidney cell electrophoresis

    NASA Technical Reports Server (NTRS)

    Todd, P.

    1979-01-01

    A kidney cell electrophoresis technique is described in four parts: (1) the development and testing of electrophoresis solutions; (2) optimization of freezing and thawing; (3) procedures for evaluation of separated kidney cells; and (4) electrophoretic mobility characteristics of kidney cells.

  18. Kidney cell electrophoresis

    NASA Technical Reports Server (NTRS)

    Todd, P.

    1980-01-01

    The following aspects of kidney cell electrophoresis are discussed: (1) the development and testing of electrophoresis solutions; (2) optimization of freezing and thawing; (3) procedures for evaluation of separated kidney cells; and (4) electrophoretic mobility characterization of kidney cells.

  19. Kidney cell electrophoresis

    NASA Technical Reports Server (NTRS)

    Todd, P. W.

    1985-01-01

    Tasks were undertaken in support of two objectives. They are: (1) to carry out electrophoresis experiments on cells in microgravity; and (2) assess the feasibility of using purified kidney cells from embryonic kidney cultures as a source of important cell products. Investigations were carried out in the following areas: (1) ground based electrophoresis technology; (2) cell culture technology; (3) electrophoresis of cells; (4) urokinase assay research; (5) zero-g electrophoresis; and (6) flow cytometry.

  20. Detection and analysis of protein-protein interactions in organellar and prokaryotic proteomes by native gel electrophoresis: (Membrane) protein complexes and supercomplexes.

    PubMed

    Krause, Frank

    2006-07-01

    It is an essential and challenging task to unravel protein-protein interactions in their actual in vivo context. Native gel systems provide a separation platform allowing the analysis of protein complexes on a rather proteome-wide scale in a single experiment. This review focus on blue-native (BN)-PAGE as the most versatile and successful gel-based approach to separate soluble and membrane protein complexes of intricate protein mixtures derived from all biological sources. BN-PAGE is a charge-shift method with a running pH of 7.5 relying on the gentle binding of anionic CBB dye to all membrane and many soluble protein complexes, leading to separation of protein species essentially according to their size and superior resolution than other fractionation techniques can offer. The closely related colorless-native (CN)-PAGE, whose applicability is restricted to protein species with intrinsic negative net charge, proved to provide an especially mild separation capable of preserving weak protein-protein interactions better than BN-PAGE. The essential conditions determining the success of detecting protein-protein interactions are the sample preparations, e.g. the efficiency/mildness of the detergent solubilization of membrane protein complexes. A broad overview about the achievements of BN- and CN-PAGE studies to elucidate protein-protein interactions in organelles and prokaryotes is presented, e.g. the mitochondrial protein import machinery and oxidative phosphorylation supercomplexes. In many cases, solubilization with digitonin was demonstrated to facilitate an efficient and particularly gentle extraction of membrane protein complexes prone to dissociation by treatment with other detergents. In general, analyses of protein interactomes should be carried out by both BN- and CN-PAGE.

  1. First evidence of a membrane-bound, tyramine and beta-phenylethylamine producing, tyrosine decarboxylase in Enterococcus faecalis: a two-dimensional electrophoresis proteomic study.

    PubMed

    Pessione, Enrica; Pessione, Alessandro; Lamberti, Cristina; Coïsson, Daniel Jean; Riedel, Kathrin; Mazzoli, Roberto; Bonetta, Silvia; Eberl, Leo; Giunta, Carlo

    2009-05-01

    The soluble and membrane proteome of a tyramine producing Enterococcus faecalis, isolated from an Italian goat cheese, was investigated. A detailed analysis revealed that this strain also produces small amounts of beta-phenylethylamine. Kinetics of tyramine and beta-phenylethylamine accumulation, evaluated in tyrosine plus phenylalanine-enriched cultures (stimulated condition), suggest that the same enzyme, the tyrosine decarboxylase (TDC), catalyzes both tyrosine and phenylalanine decarboxylation: tyrosine was recognized as the first substrate and completely converted into tyramine (100% yield) while phenylalanine was decarboxylated to beta-phenylethylamine (10% yield) only when tyrosine was completely depleted. The presence of an aspecific aromatic amino acid decarboxylase is a common feature in eukaryotes, but in bacteria only indirect evidences of a phenylalanine decarboxylating TDC have been presented so far. Comparative proteomic investigations, performed by 2-DE and MALDI-TOF/TOF MS, on bacteria grown in conditions stimulating tyramine and beta-phenylethylamine biosynthesis and in control conditions revealed 49 differentially expressed proteins. Except for aromatic amino acid biosynthetic enzymes, no significant down-regulation of the central metabolic pathways was observed in stimulated conditions, suggesting that tyrosine decarboxylation does not compete with the other energy-supplying routes. The most interesting finding is a membrane-bound TDC highly over-expressed during amine production. This is the first evidence of a true membrane-bound TDC, longly suspected in bacteria on the basis of the gene sequence.

  2. Kidney Cell Electrophoresis

    NASA Technical Reports Server (NTRS)

    Todd, P.

    1985-01-01

    Materials and procedures for microgravity electrophoresis of living human embryonic kidney cells were evaluated, ground support in the form of analytical cell electrophoresis and flow cytometry was provided and cells returned from space flight were analyzed. Preflight culture media, electrophoresis buffer, fraction collection media, temperature profiles, and urokinase assay procedures were tested prior to flight. Electrophoretic mobility distributions of aliquots of the cell population to be fractionated in flight were obtained. The protocol established and utilized is given.

  3. Protein electrophoresis - serum

    MedlinePlus

    ... Hemolysis Hyperimmunization Immunoelectrophoresis - blood Immunofixation blood test Liver disease Malignancy Malnutrition Nephrotic syndrome Rheumatoid arthritis Serum globulin electrophoresis Serum iron test Systemic lupus erythematosus ...

  4. Affinity in electrophoresis.

    PubMed

    Heegaard, Niels H H

    2009-06-01

    The journal Electrophoresis has greatly influenced my approaches to biomolecular affinity studies. The methods that I have chosen as my main tools to study interacting biomolecules--native gel and later capillary zone electrophoresis--have been the topic of numerous articles in Electrophoresis. Below, the role of the journal in the development and dissemination of these techniques and applications reviewed. Many exhaustive reviews on affinity electrophoresis and affinity CE have been published in the last few years and are not in any way replaced by the present deliberations that are focused on papers published by the journal.

  5. Mechanisms of Membrane Preparation and Membrane Assays.

    DTIC Science & Technology

    The course of the work for the report period involved: Evaluating and developing testing procedures for membrane filters, and the construction, procurement of equipment for such testing; and Numerous sol preparations and castings of membranes using the acetate-butyrate esters of cellulose in lieu of the cellulose acetate in conjunction with the cellulose nitrate base of formulation. (Author)

  6. Electrophoresis of biological materials

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The selection of biological products was studied for electrophoresis in space. Free flow electrophoresis, isoelectric focusing, and isotachophoresis are described. The candidates discussed include: immunoglobulins and gamma globulins; isolated islet of langerhans from pancreas; bone marrow; tumor cells; kidney cells, cryoprecipitate; and column separated cultures.

  7. Automatic multiple applicator electrophoresis

    NASA Technical Reports Server (NTRS)

    Grunbaum, B. W.

    1977-01-01

    Easy-to-use, economical device permits electrophoresis on all known supporting media. System includes automatic multiple-sample applicator, sample holder, and electrophoresis apparatus. System has potential applicability to fields of taxonomy, immunology, and genetics. Apparatus is also used for electrofocusing.

  8. Improved Electrophoresis Cell

    NASA Technical Reports Server (NTRS)

    Rhodes, P. H.; Snyder, R. S.

    1982-01-01

    Several proposed modifications are expected to improve performance of a continous-flow electrophoresis cell. Changes would allow better control of buffer flow and would increase resolution by suppressing thermal gradients. Improved electrophoresis device would have high resolution and be easy to operate. Improvements would allow better flow control and heat dissipation.

  9. Electrophoresis for biological production

    NASA Technical Reports Server (NTRS)

    Mccreight, L. R.

    1977-01-01

    Preparative electrophoresis may provide a unique method for meeting ever more stringent purity requirements. Prolonged near zero gravity in space may permit the operation of preparative electrophoresis equipment with 100 times greater throughput than is currently available. Some experiments with influenza Virus Antigen, Erythropoietin and Antihemophaliac Factor, along with process and economic projections, are briefly reviewed.

  10. Electrophoresis experiments for space

    NASA Astrophysics Data System (ADS)

    Snyder, Robert S.; Rhodes, Percy H.

    2000-01-01

    It has long been hoped that space could alleviate the problems of large-scale, high-capacity electrophoresis. Support media and reduced chamber dimensions of capillary electrophoresis have established the physical boundaries for Earth-based systems. Ideally, electrophoresis conducted in a virtual weightless environment in an unrestricted ``free'' fluid should have great potential. The electrophoresis and isoelectric focusing experiments done in the reduced gravity over the past twenty-five years have demonstrated the absence of thermal convection and sedimentation as well as the presence of electrohydrodynamics that requires careful control. One commercial venture produced gram amounts of an electrophoretically purified protein during seven Space Shuttle flights but the market disappeared in the six years between experiment conception and performance on the Space Shuttle. Our accumulated experience in microgravity plus theoretical models predict improvements that should be possible with electrophoresis if past problems are considered and both invention of new technologies and innovation of procedures on the Space Station are encouraged. .

  11. Sphingolipids contribute to acetic acid resistance in Zygosaccharomyces bailii.

    PubMed

    Lindahl, Lina; Genheden, Samuel; Eriksson, Leif A; Olsson, Lisbeth; Bettiga, Maurizio

    2016-04-01

    Lignocellulosic raw material plays a crucial role in the development of sustainable processes for the production of fuels and chemicals. Weak acids such as acetic acid and formic acid are troublesome inhibitors restricting efficient microbial conversion of the biomass to desired products. To improve our understanding of weak acid inhibition and to identify engineering strategies to reduce acetic acid toxicity, the highly acetic-acid-tolerant yeast Zygosaccharomyces bailii was studied. The impact of acetic acid membrane permeability on acetic acid tolerance in Z. bailii was investigated with particular focus on how the previously demonstrated high sphingolipid content in the plasma membrane influences acetic acid tolerance and membrane permeability. Through molecular dynamics simulations, we concluded that membranes with a high content of sphingolipids are thicker and more dense, increasing the free energy barrier for the permeation of acetic acid through the membrane. Z. bailii cultured with the drug myriocin, known to decrease cellular sphingo-lipid levels, exhibited significant growth inhibition in the presence of acetic acid, while growth in medium without acetic acid was unaffected by the myriocin addition. Furthermore, following an acetic acid pulse, the intracellular pH decreased more in myriocin-treated cells than in control cells. This indicates a higher inflow rate of acetic acid and confirms that the reduction in growth of cells cultured with myriocin in the medium with acetic acid was due to an increase in membrane permeability, thereby demonstrating the importance of a high fraction of sphingolipids in the membrane of Z. bailii to facilitate acetic acid resistance; a property potentially transferable to desired production organisms suffering from weak acid stress.

  12. Binary Oscillatory Crossflow Electrophoresis

    NASA Technical Reports Server (NTRS)

    Molloy, Richard F.; Gallagher, Christopher T.; Leighton, David T., Jr.

    1996-01-01

    We present preliminary results of our implementation of a novel electrophoresis separation technique: Binary Oscillatory Cross flow Electrophoresis (BOCE). The technique utilizes the interaction of two driving forces, an oscillatory electric field and an oscillatory shear flow, to create an active binary filter for the separation of charged species. Analytical and numerical studies have indicated that this technique is capable of separating proteins with electrophoretic mobilities differing by less than 10%. With an experimental device containing a separation chamber 20 cm long, 5 cm wide, and 1 mm thick, an order of magnitude increase in throughput over commercially available electrophoresis devices is theoretically possible.

  13. Preparative electrophoresis experiment design

    NASA Technical Reports Server (NTRS)

    Thiehler, A.

    1972-01-01

    A multifaceted study supporting the NASA programs to develop a space electrophoresis capability has been conducted. The study involved principally the technique of continuous free electrophoresis. It comprised a critical review of the art, study of new techniques for enhancing resolution and stability, and construction and initial testing of a high resolution cell. The effort resulted in a significant advance in free electrophoresis technique. It has provided also a much improved base for developments exploiting the added advantages of a zero-gravity environment.

  14. Shaping Crystals using Electrophoresis

    NASA Astrophysics Data System (ADS)

    Palacci, Jeremie; Mackiewicz, Kristian

    2016-11-01

    Electrophoresis is size and shape independent as stressed by Morrison in his seminal paper. Here we present an original approach to reshape colloidal crystals using an electric field as a carving tool.

  15. Electrophoresis operations in space

    NASA Technical Reports Server (NTRS)

    Richman, D. W.

    1982-01-01

    Application of electrophoresis in space processing is described. Spaceborne experiments in areas such as biological products and FDA approved drugs are discussed. These experiments will be carried on shuttle payloads.

  16. Recent advances in preparative electrophoresis

    NASA Technical Reports Server (NTRS)

    Mosher, Richard A.; Thormann, Wolfgang; Egen, Ned B.; Couasnon, Pascal; Sammons, David W.

    1987-01-01

    Various approaches for preparative electrophoresis, and three new instruments for preparative electrophoresis are discussed. Consideration is given to isoelectric focusing, isotachophoresis, and zone electrophoresis, three gel-based electrophoresis methods. The design, functions, and performance of the Elphor VaP 21 device of Hannig (1982), the shear-stabilized BIOSTREAM separator of Thompson (1983), and the recycling isoelectric focusing device are described.

  17. Capillary electrophoresis-mass spectrometry of carbohydrates

    PubMed Central

    Zaia, Joseph

    2014-01-01

    The development of methods for capillary electrophoresis (CE) with on-line mass spectrometric detection (CE/MS) is driven by the need for accurate, robust and sensitive glycomics analysis for basic biomedicine, biomarker discovery, and analysis of recombinant protein therapeutics. One important capability is to profile glycan mixtures with respect to the patterns of substituents including sialic acids, acetate, sulfate, phosphate, and other groups. There is additional need for an MS-compatible separation system capable of resolving carbohydrate isomers. This review summarizes applications of CS/MS to analysis of carbohydrates, glycoproteins and glycopeptides that have appeared since 2008. Readers are referred to recent comprehensive reviews covering earlier publications. PMID:23386333

  18. Capillary electrophoresis-mass spectrometry of carbohydrates.

    PubMed

    Zaia, Joseph

    2013-01-01

    The development of methods for capillary electrophoresis (CE) with on-line mass spectrometric detection (CE/MS) is driven by the need for accurate, robust, and sensitive glycomics analysis for basic biomedicine, biomarker discovery, and analysis of recombinant protein therapeutics. One important capability is to profile glycan mixtures with respect to the patterns of substituents including sialic acids, acetate, sulfate, phosphate, and other groups. There is additional need for an MS-compatible separation system capable of resolving carbohydrate isomers. This chapter summarizes applications of CS/MS to analysis of carbohydrates, glycoproteins, and glycopeptides that have appeared since 2008. Readers are referred to recent comprehensive reviews covering earlier publications.

  19. Management of recurrent inflammatory choroidal neovascular membrane secondary to Vogt-Koyanagi-Harada syndrome, using combined intravitreal injection of bevacizumab and triamcinolone acetate

    PubMed Central

    Pai, Sivakami A; Hebri, Sudhira P; Lootah, Afra M

    2012-01-01

    The purpose of this report is to evaluate the efficacy and safety of combined intravitreal injection of bevacizumab and intravitreal triamcinolone acetonide (IVTA) for recurrent inflammatory choroidal neovascular membrane (CNVM). It was a prospective interventional study of a young female, who was a known case of Vogt-Koyanagi-Harada syndrome. She presented with an inflammatory choroidal neovascualar membrane and signs of panuveitis in the right eye. She underwent a complete ophthalmic examination. She was given intravitreal injection of bevacizumab and IVTA at different sites. There was complete regression of CNVM and ocular inflammation within a week. After six months, she had recurrence of CNVM in the same eye, which was treated similarly. There was a complete resolution of CNVM and ocular inflammation after the combination therapy and systemic steroids, until one year of follow-up. No serious systemic or ocular adverse events were noted. Combination therapy appears to be an effective and safe method in the management of recurrent inflammatory CNVM. PMID:23202396

  20. Membrane Technology: A Search for Membranes for Submarine Atmosphere Control

    DTIC Science & Technology

    1992-01-01

    dimethyl silicone (25%) rubber membranes exhibit the highest permeability for carbon dioxide, while cellulose acetate exhibits the highest separation...factor (10.9) of carbon dioxide to oxygen. However, an immobilized film membrane (IFM) device constructed of a cellulose acetate membrane impregnated

  1. Lectin affinity electrophoresis.

    PubMed

    Kobayashi, Yuka

    2014-01-01

    An interaction or a binding event typically changes the electrophoretic properties of a molecule. Affinity electrophoresis methods detect changes in the electrophoretic pattern of molecules (mainly macromolecules) that occur as a result of biospecific interactions or complex formation. Lectin affinity electrophoresis is a very effective method for the detection and analysis of trace amounts of glycobiological substances. It is particularly useful for isolating and separating the glycoisomers of target molecules. Here, we describe a sensitive technique for the detection of glycoproteins separated by agarose gel-lectin affinity electrophoresis that uses antibody-affinity blotting. The technique is tested using α-fetoprotein with lectin (Lens culinaris agglutinin and Phaseolus vulgaris agglutinin)-agarose gels.

  2. Electrophoresis in space.

    PubMed

    Bauer, J; Hymer, W C; Morrison, D R; Kobayashi, H; Seaman, G V; Weber, G

    1999-01-01

    Programs for free flow electrophoresis in microgravity over the past 25 years are reviewed. Several studies accomplished during 20 spaceflight missions have demonstrated that sample throughput is significantly higher in microgravity than on the ground. Some studies have shown that resolution is also increased. However, many cell separation trials have fallen victim to difficulties associated with experimenting in the microgravity environment such as microbial contamination, air bubbles in electrophoresis chambers, and inadequate facilities for maintaining cells before and after separation. Recent studies suggest that the charge density of cells at their surface may also be modified in microgravity. If this result is confirmed, a further cellular mechanism of "sensing" the low gravity environment will have been found. Several free fluid electrophoresis devices are now available. Most have been tried at least once in microgravity. Newer units not yet tested in spaceflight have been designed to accommodate problems associated with space processing. The USCEPS device and the Japanese FFEU device are specifically designed for sterile operations, whereas the Octopus device is designed to reduce electroosmotic and electrohydrodynamic effects, which become dominant and detrimental in microgravity. Some of these devices will also separate proteins by zone electrophoresis, isotachophoresis, or isoelectric focusing in a single unit. Separation experiments with standard test particles are useful and necessary for testing and optimizing new space hardware. A cohesive free fluid electrophoresis program in the future will obviously require (1) flight opportunities and funding, (2) identification of suitable cellular and macromolecular candidate samples, and (3) provision of a proper interface of electrophoresis processing equipment with biotechnological facilities--equipment like bioreactors and protein crystal growth chambers. The authors feel that such capabilities will lead to

  3. Pulse Field Gel Electrophoresis

    PubMed Central

    Sharma-Kuinkel, Batu K.; Rude, Thomas H.; Fowler, Vance G.

    2015-01-01

    Pulse Field Gel Electrophoresis (PFGE) is a powerful genotyping technique used for the separation of large DNA molecules (entire genomic DNA) after digesting it with unique restriction enzymes and applying to a gel matrix under the electric field that periodically changes direction. PFGE is a variation of agarose gel electrophoresis that permits analysis of bacterial DNA fragments over an order of magnitude larger than that with conventional restriction enzyme analysis. It provides a good representation of the entire bacterial chromosome in a single gel with a highly reproducible restriction profile, providing clearly distinct and well-resolved DNA fragments. PMID:25682374

  4. Pulse Field Gel Electrophoresis.

    PubMed

    Sharma-Kuinkel, Batu K; Rude, Thomas H; Fowler, Vance G

    2016-01-01

    Pulse Field Gel Electrophoresis (PFGE) is a powerful genotyping technique used for the separation of large DNA molecules (entire genomic DNA) after digesting it with unique restriction enzymes and applying to a gel matrix under the electric field that periodically changes direction. PFGE is a variation of agarose gel electrophoresis that permits analysis of bacterial DNA fragments over an order of magnitude larger than that with conventional restriction enzyme analysis. It provides a good representation of the entire bacterial chromosome in a single gel with a highly reproducible restriction profile, providing clearly distinct and well-resolved DNA fragments.

  5. Fraction collector for electrophoresis

    NASA Technical Reports Server (NTRS)

    Bier, M.

    1977-01-01

    Rotating-tube electrophoresis apparatus employs rotating jet of eluting buffer to reduce effects of convection during separation. Designed for separation of microorganisms and biological species, system combines gravity/gradient compensating of lumen with buffer flush at fraction outlet to increase separation efficiency.

  6. DNA ELECTROPHORESIS AT SURFACES

    SciTech Connect

    RAFAILOVICH, MIRIAM; SOKOLOV, JONATHAN; GERSAPPE, DILIP

    2003-09-01

    During this year we performed two major projects: I. We developed a detailed theoretical model which complements our experiments on surface DNA electrophoresis. We found that it was possible to enhance the separation of DNA chains by imposing a chemical nanoscale pattern on the surface. This approach utilized the surface interaction effect of the DNA chains with the substrate and is a refinement to our previous method in which DNA chains were separated on homogeneous flat surfaces. By introducing the nano-patterns on the surface, the conformational changes of DNA chains of different lengths can be amplified, which results in the different friction strengths with the substrate surface. Our results also show that, when compared to the DNA electrophoresis performed on homogeneous flat surfaces, nanopatterned surfaces offer a larger window in choosing different surface interactions to achieve separation. II. In collaboration with a large international manufacturer of skin care products we also embarked on a project involving photo toxicity of titanium dioxide nanoparticles, which are a key ingredient in sunscreen and cosmetic lotions. The results clearly implicated the nanoparticles in catalyzing damage to chromosomal DNA. We then used this knowledge to develop a polymer/anti-oxidant coating which prevented the photocatalytic reaction on DNA while still retaining the UV absorptive properties of the nanoparticles. The standard gel electrophoresis was not sufficient in determining the extent of the DNA damage. The conclusions of this study were based predominantly on analysis obtained with the surface electrophoresis method.

  7. Automatic multiple-sample applicator and electrophoresis apparatus

    NASA Technical Reports Server (NTRS)

    Grunbaum, B. W. (Inventor)

    1977-01-01

    An apparatus for performing electrophoresis and a multiple-sample applicator is described. Electrophoresis is a physical process in which electrically charged molecules and colloidal particles, upon the application of a dc current, migrate along a gel or a membrane that is wetted with an electrolyte. A multiple-sample applicator is provided which coacts with a novel tank cover to permit an operator either to depress a single button, thus causing multiple samples to be deposited on the gel or on the membrane simultaneously, or to depress one or more sample applicators separately by means of a separate button for each applicator.

  8. A Study of Bonding Cellulose Acetate to Polyarylsulfone,

    DTIC Science & Technology

    The objective of this study was to develop a method by which ultrathin films (500 to 1500 angstroms in thickness) of cellulose acetate could be...rejecting and flow characteristics of the cellulose acetate -polysulfone composite. A successful method was found to be the application of a dilute...solution (1.5 percent by weight) of Resyn 26-2404 to the polysulfone before casting the cellulose acetate membrane. A TYPICAL COMPOSITE WITH A SPRAYED

  9. Happy bicentennial, electrophoresis!

    PubMed

    Righetti, Pier Giorgio

    2009-12-01

    A short survey of electrophoresis and a celebration of its bicentennial, with some remarkable mementos and a list of books that shaped the field. Where one also learns of a secret production plant with a huge-scale electrophoretic apparatus for skimming of latex from Hevea brasiliensis and keeping the wheels of the Ally Army running during World War II. And of cyber (mammoth) 2D gels of 1.5 x 1 m in size accommodating >12,000 spots.

  10. PAPER ELECTROPHORESIS OF SALIVA ALBUMINS (ELEKTROFOREZA BIBULOWA BIALEK SLINY),

    DTIC Science & Technology

    The proteins of mixed human saliva were concentrated by prevaporation, separated by electrophoresis and the fractions obtained there were of determined quantitatively. Three different techniques of separation were developed. The best separation was obtained on the cellulose acetate strips in veronal buffer pH 8.6. The electrophorograms of the saliva proteins were compared with those of serum proteins separated under the same conditions. (Author)

  11. Electrophoresis experiments in microgravity

    NASA Technical Reports Server (NTRS)

    Snyder, Robert S.; Rhodes, Percy H.

    1991-01-01

    The use of the microgravity environment to separate and purify biological cells and proteins has been a major activity since the beginning of the NASA Microgravity Science and Applications program. Purified populations of cells are needed for research, transplantation and analysis of specific cell constituents. Protein purification is a necessary step in research areas such as genetic engineering where the new protein has to be separated from the variety of other proteins synthesized from the microorganism. Sufficient data are available from the results of past electrophoresis experiments in space to show that these experiments were designed with incomplete knowledge of the fluid dynamics of the process including electrohydrodynamics. However, electrophoresis is still an important separation tool in the laboratory and thermal convection does limit its performance. Thus, there is a justification for electrophoresis but the emphasis of future space experiments must be directed toward basic research with model experiments to understand the microgravity environment and fluid analysis to test the basic principles of the process.

  12. Preparative electrophoresis for space

    NASA Technical Reports Server (NTRS)

    Rhodes, Percy H.; Snyder, Robert S.

    1988-01-01

    A premise of continuous flow electrophoresis is that removal of buoyance-induced thermal convection caused by axial and lateral temperature gradients results in ideal performance of these instruments in space. Although these gravity dependent phenomena disturb the rectilinear flow in the separation chamber when high voltage gradients or thick chamber are used, distortion of the injected sample stream due to electrodynamic effects cause major broadening of the separated bands. The electrophoresis separation process is simple, however flow local to the sample filament produced by the applied electric field were not considered. These electrohydrodynamic flows distort the sample stream and limit the separation. Also, electroosmosis and viscous flow combine to further distort the process. A moving wall concept is being proposed for space which will eliminate and control the disturbances. The moving wall entrains the fluid to move as a rigid body and produces a constant residence time for all samples distributed across the chamber thickness. The moving wall electrophoresis chamber can only be operated in space because there is no viscous flow in the chamber to stabilize against thermal convection.

  13. Preparative electrophoresis for space

    NASA Technical Reports Server (NTRS)

    Rhodes, Percy H.; Snyder, Robert S.

    1987-01-01

    A premise of continuous flow electrophoresis is that removal of buoyancy-induced thermal convection caused by axial and lateral temperature gradients results in ideal performance of these instruments in space. Although these gravity dependent phenomena disturb the rectilinear flow in the separation chamber when high voltage gradients or thick chambers are used, distortion of the injected sample stream due to electrohydrodynamic effects cause major broadening of the separated bands. The electrophoresis separation process is simple, however flow local to the sample filament produced by the applied electric field have not been considered. These electrohydrodynamic flows distort the sample stream and limit the separation. Also, electroosmosis and viscous flow combine to further distort the process. A moving wall concept is being proposed for space which will eliminate and control the disturbances. The moving wall entrains the fluid to move as a rigid body and produces a constant residence time for all samples distributed across the chamber thickness. The moving wall electrophoresis chamber can only be operated in space because there is no viscous flow in the chamber to stabilize against thermal convection.

  14. Determination of terbinafine in pharmaceuticals and dialyzates by capillary electrophoresis.

    PubMed

    Mikus, Peter; Valásková, Iva; Havránek, Emil

    2005-02-28

    A capillary electrophoresis method has been developed for the separation and determination of terbinafine (TER) in various pharmaceutically relevant matrices. Capillary zone electrophoresis (CZE) separation and UV absorbance photometric detection were carried out in a 160mm capillary tube with a 300mum i.d., hydrodynamically (membrane) closed. The influences of pH, carrier cation and counterion on migration parameters of TER were studied and the following conditions were selected: a 20mmoll(-1) glycine running buffer adjusted to pH 2.7 with acetic acid, 0.2% (w/v) methylhydroxyethylcellulose (m-HEC) as an electro-osmotic flow (EOF) suppressor, a 250muA driving current, and 20 degrees C. The optimized separation conditions were convenient for the determination of TER in commercial tablets and spray and in dialyzates. Here, the dialysis was used to investigate in vitro permeation of TER through the skin from the gel. The samples of dialyzates were examined with and without simple extraction procedure and the results were compared. A permeation profile of the drug present in the gel of given composition was obtained analyzing pretreated samples. The proposed electrophoretic method was successfully validated. It was suitable for the simple, sensitive, rapid and highly reproducible assay of TER. CZE analysis was completed within 5.5min. The detection limit of TER was 1.73mumoll(-1) at a 224nm detection wavelength. The intra- and inter-laboratory precisions over the concentration range 6.0-60.0mumoll(-1) were between 0.32-0.69% and 1.04-1.44% including R.S.D. of migration times and peak areas, respectively. The mean absolute recoveries of drugs from samples were found to be 98.34 (tablets) and 99.47% (spray). It is suggested that there are potentialities to determine TER present in unpretreated complex samples, as CZE in a hydrodynamically closed separation system may be easily on-line combinable with purification and preconcentration CE modes (e.g., isotachophoresis

  15. Polyaniline Membranes for Separation Applications

    DTIC Science & Technology

    2007-11-02

    High quality membranes of poly aniline/ethylaniline copolymers along with polyaniline /polyimide blends have been synthesized . Water permeates... polyaniline is among the most selective membranes yet developed for water/acetic acid separations: e.g. at 50% water/50% acetic acid the selectivity alpha is

  16. Evaluation of Pyrrones as Membranes.

    DTIC Science & Technology

    1970-09-01

    The data indicate comparable flux values and superior water-to-salt permeabilities of the Pyrrones relative to symmetric cellulose acetate membranes...could lead to substantial improvements over asymmetric cellulose acetate , from which the best reverse osmosis membranes are currently prepared.

  17. Preparation of vinyl acetate

    DOEpatents

    Tustin, Gerald Charles; Zoeller, Joseph Robert; Depew, Leslie Sharon

    1998-01-01

    This invention pertains to the preparation of vinyl acetate by contacting a mixture of hydrogen and ketene with a heterogeneous catalyst containing a transition metal to produce acetaldehyde, which is then reacted with ketene in the presence of an acid catalyst to produce vinyl acetate.

  18. Preparation of vinyl acetate

    DOEpatents

    Tustin, G.C.; Zoeller, J.R.; Depew, L.S.

    1998-03-24

    This invention pertains to the preparation of vinyl acetate by contacting a mixture of hydrogen and ketene with a heterogeneous catalyst containing a transition metal to produce acetaldehyde, which is then reacted with ketene in the presence of an acid catalyst to produce vinyl acetate.

  19. The Properties of Water in Polymeric Membranes.

    DTIC Science & Technology

    The relative amounts of freezing and non-freezing water in various water-wet cellulose acetate (CA) membranes have been determined by NMR techniques...by reverse osmosis is compared to that of the commonly used cellulose acetate .

  20. Multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, E.S.; Li, Q.; Lu, X.

    1998-04-21

    The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification (``base calling``) is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations. 19 figs.

  1. Multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, E.S.; Chang, H.T.; Fung, E.N.; Li, Q.; Lu, X.

    1996-12-10

    The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification (``base calling``) is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations. 19 figs.

  2. Multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, Edward S.; Li, Qingbo; Lu, Xiandan

    1998-04-21

    The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification ("base calling") is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations.

  3. Multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, Edward S.; Chang, Huan-Tsang; Fung, Eliza N.; Li, Qingbo; Lu, Xiandan

    1996-12-10

    The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification ("base calling") is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations.

  4. Apparatus for electrophoresis separation

    DOEpatents

    Anderson, Norman L.

    1978-01-01

    An apparatus is disclosed for simultaneously performing electrophoresis separations on a plurality of slab gels containing samples of protein, protein subunits or nucleic acids. A reservoir of buffer solution is divided into three compartments by two parallel partitions having vertical slots spaced along their length. A sheet of flexible, electrically insulative material is attached to each partition and is provided with vertical slits aligned with the slots. Slab-gel holders are received within the slots with the flexible material folded outwardly as flaps from the slits to overlay portions of the holder surfaces and thereby act as electrical and liquid seals. An elongated, spaghetti-like gel containing a sample of specimen that was previously separated by isoelectric focusing techniques is vertically positioned along a marginal edge portion of the slab gel. On application of an electrical potential between the two outer chambers of buffer solution, a second dimensional electrophoresis separation in accordance with molecular weight occurs as the specimen molecules migrate across the slab gel.

  5. Agarose gel electrophoresis.

    PubMed

    Smith, D R

    1993-01-01

    After digestion of DNA with a restriction enzyme (Chapter 50), it is usually necessary, for both preparative and analytical purposes, to separate and visualize the products. In most cases, where the products are between 200 and 20,000 bp long, this is achieved by agarose gel electrophoresis. Agarose is a linear polymer that is extracted from seaweed and sold as a white powder. The powder is melted in buffer and allowed to cool, whereby the agarose forms a gel by hydrogen bonding. The hardened matrix contains pores, the size of which depends on the concentration of agarose. The concentration of agarose is referred to as a percentage of agarose to volume of buffer (w/v), and agarose gels are normally in the range of 0.3 to 3%. Many different apparatus arrangements have been devised to run agarose gels; for example, they can be run horizontally or vertically, and the current can be conducted by wicks or the buffer solution. However, today, the "submarine" gel system is almost universally used. In this method, the agarose gel is formed on a supporting plate, and then the plate is submerged into a tank containing a suitable electrophoresis buffer. Wells are preformed in the agarose gel with the aid of a "comb" that is inserted into the cooling agarose before the agarose has gelled. Into these wells are loaded the sample to be analyzed, which has been mixed with a dense solution (a loading buffer) to ensure that the sample sinks into the wells.

  6. Nanofabrication in cellulose acetate.

    PubMed

    Zeng, Hongjun; Lajos, Robert; Metlushko, Vitali; Elzy, Ed; An, Se Young; Sautner, Joshua

    2009-03-07

    We have demonstrated nanofabrication with commercialized cellulose acetate. Cellulose acetate is used for bulk nanofabrication and surface nanofabrication. In bulk nanofabrication, cellulose acetate reacts with an e-beam and permanent patterns are formed in it instead of being transferred to other substrates. We have studied the nano relief modulation performance of cellulose acetate before and after development. The depth of the nanopatterns is magnified after development, and is varied by exposing dosage and line width of the pattern. The thinnest 65 nm wide line is achieved in the bulk fabrication. We also demonstrate a binary phase Fresnel lens array which is directly patterned in a cellulose acetate sheet. Because of its unique mechanical and optical properties, cellulose is a good candidate for a template material for soft imprinting lithography. In the surface nanofabrication, cellulose acetate thin film spin-coated on silicon wafers is employed as a new resist for e-beam lithography. We achieved 50 nm lines with 100 nm pitches, dots 50 nm in diameter, and single lines with the smallest width of 20 nm. As a new resist of e-beam lithography, cellulose acetate has high resolution comparable with conventional resists, while having several advantages such as low cost, long stock time and less harmfulness to human health.

  7. Vesicles protect activated acetic acid.

    PubMed

    Todd, Zoe R; House, Christopher H

    2014-10-01

    Abstract Methyl thioacetate, or activated acetic acid, has been proposed to be central to the origin of life and an important energy currency molecule in early cellular evolution. We have investigated the hydrolysis of methyl thioacetate under various conditions. Its uncatalyzed rate of hydrolysis is about 3 orders of magnitude faster (K=0.00663 s(-1); 100°C, pH 7.5, concentration=0.33 mM) than published rates for its catalyzed production, making it unlikely to accumulate under prebiotic conditions. However, our experiments showed that methyl thioacetate was protected from hydrolysis when inside its own hydrophobic droplets. Further, we found that methyl thioacetate protection from hydrolysis was also possible in droplets of hexane and in the membranes of nonanoic acid vesicles. Thus, the hydrophobic regions of prebiotic vesicles and early cell membranes could have offered a refuge for this energetic molecule, increasing its lifetime in close proximity to the reactions for which it would be needed. This model of early energy storage evokes an additional critical function for the earliest cell membranes.

  8. Derivatization in Capillary Electrophoresis.

    PubMed

    Marina, M Luisa; Castro-Puyana, María

    2016-01-01

    Capillary electrophoresis is a well-established separation technique in analytical research laboratories worldwide. Its interesting advantages make CE an efficient and potent alternative to other chromatographic techniques. However, it is also recognized that its main drawback is the relatively poor sensitivity when using optical detection. One way to overcome this limitation is to perform a derivatization reaction which is intended to provide the analyte more suitable analytical characteristics enabling a high sensitive detection. Based on the analytical step where the CE derivatization takes place, it can be classified as precapillary (before separation), in-capillary (during separation), or postcapillary (after separation). This chapter describes the application of four different derivatization protocols (in-capillary and precapillary modes) to carry out the achiral and chiral analysis of different compounds in food and biological samples with three different detection modes (UV, LIF, and MS).

  9. Electrophoresis of Positioned Nucleosomes

    PubMed Central

    Castelnovo, Martin; Grauwin, Sébastian

    2007-01-01

    We present in this article an original approach to compute the electrophoretic mobility of rigid nucleo-protein complexes like nucleosomes. This model allows us to address theoretically the influence of complex position along DNA, as well as wrapped length of DNA on the electrophoretic mobility of the complex. The predictions of the model are in qualitative agreement with experimental results on mononucleosomes assembled on short DNA fragments (<400 bp). Influences of additional experimental parameters like gel concentration, ionic strength, and effective charges are also discussed in the framework of the model, and are found to be qualitatively consistent with experiments when available. Based on the present model, we propose a simple semi-empirical formula describing positioning of nucleosomes as seen through electrophoresis. PMID:17277181

  10. Static continuous electrophoresis device

    NASA Technical Reports Server (NTRS)

    Rhodes, P. H. (Inventor)

    1982-01-01

    An apparatus is disclosed for carrying out a moving wall type electrophoresis process for separation of cellular particles. The apparatus includes a water-tight housing containing an electrolytic buffer solution. A separation chamber in the housing is defined by spaced opposed moving walls and spaced opposed side walls. Substrate assemblies, which support the moving wall include vacuum ports for positively sealing the moving walls against the substrate walls. Several suction conduits communicate with the suction ports and are arranged in the form of valleys in a grid plate. The raised land portion of the grid plat supports the substrate walls against deformation inwardly under suction. A cooling chamber is carried on the back side of plate. The apparatus also has tensioner means including roller and adjustment screws for maintaining the belts in position and a drive arrangement including an electric motor with a gear affixed to its output shaft. Electrode assemblies are disposed to provide the required electric field.

  11. Electrophoresis experiment for space

    NASA Technical Reports Server (NTRS)

    Vanderhoff, J. W.; Micale, F. J.

    1976-01-01

    The Apollo 16 electrophoresis experiment was analyzed, demonstrating that the separation of the two different-size monodisperse latexes did indeed take place, but that the separation was obscured by the pronounced electroosmotic flow of the liquid medium. The results of this experiment, however, were dramatic since it is impossible to carry out a similar separation on earth. It can be stated unequivocally from this experiment that any electrophoretic separation will be enhanced under microgravity conditions. The only question is the degree of this enhancement, which can be expected to vary from one experimental technique to another. The low-electroosmotic-mobility coating (Z6040-MC) developed under this program was found to be suitable for a free-fluid electrophoretic separation such as the experiment designed for the ASTP flight. The problem with this coating, however, is that its permanency is limited because of the slow desorption of the methylcellulose from the coated surface.

  12. Kidney cell electrophoresis, continuing task

    NASA Technical Reports Server (NTRS)

    Todd, P. W.

    1985-01-01

    Materials and procedures for microgravity electrophoresis of living human embryonic kidney cells were evaluated to provide ground support in the form of analytical cell electrophoresis and flow cytometry. Preflight culture media, electrophoresis buffer, fraction collection media, temperature profiles, and urokinase assay procedures were tested prior to flight. Electrophoretic mobility distributions of aliquots of the cell population to be fractionated in flight were obtained. Cells were prepared in suspension prior to flight in electrophoresis buffer and 10% calf serum. Electrophoretic separation proceeded in electrophoresis buffer without serum in the Continuous Flow Electrophoretic Separator, and fractions were collected into sample bags containing culture medium and concentrated serum. Fractions that yielded enough progeny cells were analyzed for morphology and electrophoretic mobility distributions. It is noted that the lowest mobility fraction studied produced higher mobility progeny while the other fractions produced progeny cells with mobilities related to the fractions from which they were collected.

  13. Electrophoresis demonstration on Apollo 16

    NASA Technical Reports Server (NTRS)

    Snyder, R. S.

    1972-01-01

    Free fluid electrophoresis, a process used to separate particulate species according to surface charge, size, or shape was suggested as a promising technique to utilize the near zero gravity condition of space. Fluid electrophoresis on earth is disturbed by gravity-induced thermal convection and sedimentation. An apparatus was developed to demonstrate the principle and possible problems of electrophoresis on Apollo 14 and the separation boundary between red and blue dye was photographed in space. The basic operating elements of the Apollo 14 unit were used for a second flight demonstration on Apollo 16. Polystyrene latex particles of two different sizes were used to simulate the electrophoresis of large biological particles. The particle bands in space were extremely stable compared to ground operation because convection in the fluid was negligible. Electrophoresis of the polystyrene latex particle groups according to size was accomplished although electro-osmosis in the flight apparatus prevented the clear separation of two particle bands.

  14. Surface Charge Measurement of SonoVue, Definity and Optison: A Comparison of Laser Doppler Electrophoresis and Micro-Electrophoresis.

    PubMed

    Ja'afar, Fairuzeta; Leow, Chee Hau; Garbin, Valeria; Sennoga, Charles A; Tang, Meng-Xing; Seddon, John M

    2015-11-01

    Microbubble (MB) contrast-enhanced ultrasonography is a promising tool for targeted molecular imaging. It is important to determine the MB surface charge accurately as it affects the MB interactions with cell membranes. In this article, we report the surface charge measurement of SonoVue, Definity and Optison. We compare the performance of the widely used laser Doppler electrophoresis with an in-house micro-electrophoresis system. By optically tracking MB electrophoretic velocity in a microchannel, we determined the zeta potentials of MB samples. Using micro-electrophoresis, we obtained zeta potential values for SonoVue, Definity and Optison of -28.3, -4.2 and -9.5 mV, with relative standard deviations of 5%, 48% and 8%, respectively. In comparison, laser Doppler electrophoresis gave -8.7, +0.7 and +15.8 mV with relative standard deviations of 330%, 29,000% and 130%, respectively. We found that the reliability of laser Doppler electrophoresis is compromised by MB buoyancy. Micro-electrophoresis determined zeta potential values with a 10-fold improvement in relative standard deviation.

  15. ((35)S)sulfate incorporation into glomerular basement membrane glycosaminoglycans is decreased in experimental diabetes

    SciTech Connect

    Cohen, M.P.; Surma, M.L.

    1981-11-01

    Isolated rat renal glomeruli incorporate radioactive sulfate into glycosaminoglycans, which are integral components of the glomerular basement membrane. Cellulose acetate electrophoresis and specific enzymatic sensitivities of glycosaminoglycans prepared after pronase digestion of purified glomerular basement membrane indicate the presence of heparan sulfate. We examined the effect of experimental diabetes on the incorporation of ((35)S)-sulfate into glycosaminoglycans deposited into newly synthesized glomerular basement membrane in vitro. Basement membranes were purified from glomeruli isolated from normal and streptozotocin-diabetic rats after incubation for 2 hr with radiolabeled sulfate and then were subjected to pronase digestion for isolation of the glycosaminoglycans. ((35)S) incorporation into basement membrane glycosaminoglycans was significantly decreased in glomeruli from diabetic animals. The addition of insulin (100 micron U/ml) in vitro did not affect ((35)S) incorporation into glycosaminoglycans of the glomerular basement membranes in normal or diabetic glomeruli. High glucose concentration (5 vs. 20 mM) was without effect in short-term incubations of glomeruli from normal animals. The results indicate that experimental diabetes influences ((35)S) sulfate incorporation into glomerular basement membrane glycosaminoglycans and suggest that decreased heparan sulfate production and/or sulfation may contribute to the increased permeability of the glomerular basement membrane in diabetes.

  16. Binary Oscillatory Crossflow Electrophoresis

    NASA Technical Reports Server (NTRS)

    Molloy, Richard F.; Gallagher, Christopher T.; Leighton, David T., Jr.

    1997-01-01

    Electrophoresis has long been recognized as an effective analytic technique for the separation of proteins and other charged species, however attempts at scaling up to accommodate commercial volumes have met with limited success. In this report we describe a novel electrophoretic separation technique - Binary Oscillatory Crossflow Electrophoresis (BOCE). Numerical simulations indicate that the technique has the potential for preparative scale throughputs with high resolution, while simultaneously avoiding many problems common to conventional electrophoresis. The technique utilizes the interaction of an oscillatory electric field and a transverse oscillatory shear flow to create an active binary filter for the separation of charged protein species. An oscillatory electric field is applied across the narrow gap of a rectangular channel inducing a periodic motion of charged protein species. The amplitude of this motion depends on the dimensionless electrophoretic mobility, alpha = E(sub o)mu/(omega)d, where E(sub o) is the amplitude of the electric field oscillations, mu is the dimensional mobility, omega is the angular frequency of oscillation and d is the channel gap width. An oscillatory shear flow is induced along the length of the channel resulting in the separation of species with different mobilities. We present a model that predicts the oscillatory behavior of charged species and allows estimation of both the magnitude of the induced convective velocity and the effective diffusivity as a function of a in infinitely long channels. Numerical results indicate that in addition to the mobility dependence, the steady state behavior of solute species may be strongly affected by oscillating fluid into and out of the active electric field region at the ends of the cell. The effect is most pronounced using time dependent shear flows of the same frequency (cos((omega)t)) flow mode) as the electric field oscillations. Under such conditions, experiments indicate that

  17. Modulation of hyaluronan synthase activity in cellular membrane fractions.

    PubMed

    Vigetti, Davide; Genasetti, Anna; Karousou, Evgenia; Viola, Manuela; Clerici, Moira; Bartolini, Barbara; Moretto, Paola; De Luca, Giancarlo; Hascall, Vincent C; Passi, Alberto

    2009-10-30

    Hyaluronan (HA), the only non-sulfated glycosaminoglycan, is involved in morphogenesis, wound healing, inflammation, angiogenesis, and cancer. In mammals, HA is synthesized by three homologous HA synthases, HAS1, HAS2, and HAS3, that polymerize the HA chain using UDP-glucuronic acid and UDP-N-acetylglucosamine as precursors. Since the amount of HA is critical in several pathophysiological conditions, we developed a non-radioactive assay for measuring the activity of HA synthases (HASs) in eukaryotic cells and addressed the question of HAS activity during intracellular protein trafficking. We prepared three cellular fractions: plasma membrane, cytosol (containing membrane proteins mainly from the endoplasmic reticulum and Golgi), and nuclei. After incubation with UDP-sugar precursors, newly synthesized HA was quantified by polyacrylamide gel electrophoresis of fluorophore-labeled saccharides and high performance liquid chromatography. This new method measured HAS activity not only in the plasma membrane fraction but also in the cytosolic membranes. This new technique was used to evaluate the effects of 4-methylumbeliferone, phorbol 12-myristate 13-acetate, interleukin 1beta, platelet-derived growth factor BB, and tunicamycin on HAS activities. We found that HAS activity can be modulated by post-translational modification, such as phosphorylation and N-glycosylation. Interestingly, we detected a significant increase in HAS activity in the cytosolic membrane fraction after tunicamycin treatment. Since this compound is known to induce HA cable structures, this result links HAS activity alteration with the capability of the cell to promote HA cable formation.

  18. Separation of plant membranes by electromigration techniques.

    PubMed

    Canut, H; Bauer, J; Weber, G

    1999-02-05

    The review focuses on the multiple separating regimes that offers the free flow electrophoresis technique: free flow zone electrophoresis, isoelectric focusing, isotachophoresis, free flow step electrophoresis. Also, the feasibility to apply either interval or continuous flow electrophoresis is evaluated. The free flow zone electrophoresis regime is generally selected for the separation of cells, organelles and membranes while the other regimes find their largest fields of applications in the purification of proteins and peptides. The latter regimes present the highest resolution efficiency. Therefore, a large part of this review is devoted to the applicabilities of these different regimes to the purification of organelles and membrane vesicles at the preparative scale. Recent developments, both in instrumentation and procedures, are described. The major achievements in plant membrane fractionation obtained with free flow electrophoresis are outlined. The related procedures are both analytical and preparative: they separate tonoplast and plasma membrane simultaneously from the same homogenate, they discriminate for one type of membrane vesicles of opposite orientation, and process large quantities of membrane material by reason of the continuous flow mode. Recent advances using electromigration techniques that permit confirmation of the dynamic state of membranes, characterisation of complex membrane-dependent functions and discovery of new membrane-localised activities are presented.

  19. Biomedical applications of capillary electrophoresis

    NASA Astrophysics Data System (ADS)

    Kartsova, L. A.; Bessonova, E. A.

    2015-08-01

    The review deals with modern analytical approaches used in capillary electrophoresis for solving medical and biological problems: search for biomarkers of various diseases and rapid diagnosis based on characteristic profiles of biologically active compounds by capillary electrophoresis with mass spectrometric detection; monitoring of the residual drugs in biological fluids for evaluating the efficiency of drug therapy; testing of the enantiomeric purity of pharmaceutical products; the use of novel materials as components of stationary and pseudo-stationary phases in capillary electrophoresis and capillary electrochromatography to increase the selectivity of separation of components of complex matrices; and identification of various on-line preconcentration techniques to reduce the detection limits of biologically active analytes. A topical trend in capillary electrophoresis required in clinical practice, viz., the design of microfluidic systems, is discussed. The bibliography includes 173 references.

  20. Copolymers For Capillary Gel Electrophoresis

    SciTech Connect

    Liu, Changsheng; Li, Qingbo

    2005-08-09

    This invention relates to an electrophoresis separation medium having a gel matrix of at least one random, linear copolymer comprising a primary comonomer and at least one secondary comonomer, wherein the comonomers are randomly distributed along the copolymer chain. The primary comonomer is an acrylamide or an acrylamide derivative that provides the primary physical, chemical, and sieving properties of the gel matrix. The at least one secondary comonomer imparts an inherent physical, chemical, or sieving property to the copolymer chain. The primary and secondary comonomers are present in a ratio sufficient to induce desired properties that optimize electrophoresis performance. The invention also relates to a method of separating a mixture of biological molecules using this gel matrix, a method of preparing the novel electrophoresis separation medium, and a capillary tube filled with the electrophoresis separation medium.

  1. DNA typing by capillary electrophoresis

    SciTech Connect

    Zhang, N.

    1997-10-08

    Capillary electrophoresis is becoming more and more important in nucleic acid analysis including DNA sequencing, typing and disease gene measurements. This work summarized the background of DNA typing. The recent development of capillary electrophoresis was also discussed. The second part of the thesis showed the principle of DNA typing based on using the allelic ladder as the absolute standard ladder in capillary electrophoresis system. Future work will be focused on demonstrating DNA typing on multiplex loci and examples of disease diagnosis in the on-line format of PCR-CE. Also capillary array electrophoresis system should allow high throughput, fast speed DNA typing. Only the introduction and conclusions for this report are available here. A reprint was removed for separate processing.

  2. Determination of glycoalkaloids and relative aglycones by nonaqueous capillary electrophoresis coupled with electrospray ionization-ion trap mass spectrometry.

    PubMed

    Bianco, Giuliana; Schmitt-Kopplin, Philippe; De Benedetto, Giuseppe; Kettrup, Antonius; Cataldi, Tommaso R I

    2002-09-01

    Glycoalkaloids are naturally occurring nitrogen-containing compounds present in many species of the family Solanaceae, including cultivated and wild potatoes (Solanum spp.), tomatoes (Lycopersicon spp.), etc. These compounds have pharmacological and toxicological effects on humans due to their significant anticholinesterase activity and disruption of cell membranes. Herein is reported the development of a capillary electrophoresis (CE) method using nonaqueous (NA) separation solutions in combination with ion trap mass spectrometry (MS and MS/MS) detection for the identification and quantification of glycoalkaloids and their relative aglycones. A mixture 90:10 v/v of MeCN-MeOH containing 50 mM ammonium acetate and 1.2 M acetic acid (applied voltage of 25.5 kV) was selected as a good compromise for the separation and detection of these compounds. The electrospray MS measurements were carried out in the positive ionization mode using a coaxial sheath liquid, methanol-water (1:1) with 1% of acetic acid at a flow rate of 2.5 microL/min. Under optimized experimental conditions, the predominant ion was the protonated molecular ion ([M+H](+)) of solanidine (m/z = 398), tomatidine (m/z = 416), chaconine (m/z = 852), solanine (m/z = 868), and tomatine (m/z = 1034). MS/MS experiments were carried out systematically by changing the relative collisional energy and monitoring the intensities of the fragment ions that were not high enough to allow better quantification than with the mother ions. The method was used for analyzing glycoalkaloids in potato extracts.

  3. On-column electrochemical detection for microchip capillary electrophoresis.

    PubMed

    Osbourn, Damon M; Lunte, Craig E

    2003-06-01

    The development of a cellulose acetate decoupler for on-column electrochemical detection in microchip capillary electrophoresis is presented. The capillary based laser-etched decoupler is translated to the planar format to isolate the detector circuit from the separation circuit. The decoupler is constructed by aligning a series of 20 30-microm holes through the coverplate of the microchip with the separation channel and casting a thin film of cellulose acetate within the holes. The decoupler shows excellent isolation of the detection circuit for separation currents up to 60 microA, with noise levels at or below 1 pA at a carbon fiber electrode. Detection limits of 25 nM were achieved for dopamine. This decoupler design combines excellent mechanical stability, effective shunting of high separation currents, and ease of manufacture.

  4. Antibody enhancement of free-flow electrophoresis

    NASA Technical Reports Server (NTRS)

    Cohly, H. H. P.; Morrison, Dennis R.; Atassi, M. Zouhair

    1988-01-01

    Specific T cell clones and antibodies (ABs) were developed to study the efficiency of purifying closely associated T cells using Continuous Flow Electrophoresis System. Enhanced separation is accomplished by tagging cells first with ABs directed against the antigenic determinants on the cell surface and then with ABs against the Fc portion of the first AB. This second AB protrudes sufficiently beyond the cell membrane and glycocalyx to become the major overall cell surface potential determinant and thus causes a reduction of electrophoretic mobility. This project was divided into three phases. Phase one included development of specific T cell clones and separation of these specific clones. Phase two extends these principles to the separation of T cells from spleen cells and immunized lymph node cells. Phase three applies this double antibody technique to the separation of T cytotoxic cells from bone marrow.

  5. PNEUMATIC MICROVALVE FOR ELECTROKINETIC SAMPLE PRECONCENTRATION AND CAPILLARY ELECTROPHORESIS INJECTION

    SciTech Connect

    Cong, Yongzheng; Rausch, Sarah J.; Geng, Tao; Jambovane, Sachin R.; Kelly, Ryan T.

    2014-10-27

    Here we show that a closed pneumatic microvalve on a PDMS chip can serve as a semipermeable membrane under an applied potential, enabling current to pass through while blocking the passage of charged analytes. Enrichment of both anionic and cationic species has been demonstrated, and concentration factors of ~70 have been achieved in just 8 s. Once analytes are concentrated, the valve is briefly opened and the sample is hydrodynamically injected onto an integrated microchip or capillary electrophoresis (CE) column. In contrast to existing preconcentration approaches, the membrane-based method described here enables both rapid analyte concentration as well as high resolution separations.

  6. Overview on mechanisms of acetic acid resistance in acetic acid bacteria.

    PubMed

    Wang, Bin; Shao, Yanchun; Chen, Fusheng

    2015-02-01

    Acetic acid bacteria (AAB) are a group of gram-negative or gram-variable bacteria which possess an obligate aerobic property with oxygen as the terminal electron acceptor, meanwhile transform ethanol and sugar to corresponding aldehydes, ketones and organic acids. Since the first genus Acetobacter of AAB was established in 1898, 16 AAB genera have been recorded so far. As the main producer of a world-wide condiment, vinegar, AAB have evolved an elegant adaptive system that enables them to survive and produce a high concentration of acetic acid. Some researches and reviews focused on mechanisms of acid resistance in enteric bacteria and made the mechanisms thoroughly understood, while a few investigations did in AAB. As the related technologies with proteome, transcriptome and genome were rapidly developed and applied to AAB research, some plausible mechanisms conferring acetic acid resistance in some AAB strains have been published. In this review, the related mechanisms of AAB against acetic acid with acetic acid assimilation, transportation systems, cell morphology and membrane compositions, adaptation response, and fermentation conditions will be described. Finally, a framework for future research for anti-acid AAB will be provided.

  7. Electrophoresis as a management tool

    USGS Publications Warehouse

    Morgan, R.P.; Chapman, J.A.; Noe, L.A.; Henny, C.J.

    1974-01-01

    The theme of this 1974 Northeast Fish and Wildlife Conference is 'A New Era'. Indeed, it is a new era for improved techniques to assist in management of our fish and wildlife resources for the maximum benefit of all. In some cases, the new techniques are primarily used in research.on fish and wildlife, and the results from the research are used to aid management and enforcement agencies in the decision-making process. One of the newer techniques that is being applied to problems in fisheries and wildlife is electrophoresis. In this paper, we review briefly the techniques of electrophoresis and illustrate research problems in wildlife and fisheries where the use of electrophoresis is now assisting or may potentially aid in management decisions.

  8. Contactless conductivity detector for microchip capillary electrophoresis.

    PubMed

    Pumera, Martin; Wang, Joseph; Opekar, Frantisek; Jelínek, Ivan; Feldman, Jason; Löwe, Holger; Hardt, Steffen

    2002-05-01

    A microfabricated electrophoresis chip with an integrated contactless conductivity detection system is described. The new contactless conductivity microchip detector is based on placing two planar sensing aluminum film electrodes on the outer side of a poly(methyl methacrylate) (PMMA) microchip (without contacting the solution) and measuring the impedance of the solution in the separation channel. The contactless route obviates problems (e.g., fouling, unwanted reactions) associated with the electrode-solution contact, offers isolation of the detection system from high separation fields, does not compromise the separation efficiency, and greatly simplifies the detector fabrication. Relevant experimental variables, such as the frequency and amplitude of the applied ac voltage or the separation voltage, were examined and optimized. The detector performance was illustrated by the separation of potassium, sodium, barium, and lithium cations and the chloride, sulfate, fluoride, acetate, and phosphate anions. The response was linear (over the 20 microM-7 mM range) and reproducible (RSD = 3.4-4.9%; n = 10), with detection limits of 2.8 and 6.4 microM (for potassium and chloride, respectively). The advantages associated with the contactless conductivity detection, along with the low cost of the integrated PMMA chip/detection system, should enhance the power and scope of microfluidic analytical devices.

  9. Contactless conductivity detector for microchip capillary electrophoresis

    NASA Technical Reports Server (NTRS)

    Pumera, Martin; Wang, Joseph; Opekar, Frantisek; Jelinek, Ivan; Feldman, Jason; Lowe, Holger; Hardt, Steffen; Svehla, D. (Principal Investigator)

    2002-01-01

    A microfabricated electrophoresis chip with an integrated contactless conductivity detection system is described. The new contactless conductivity microchip detector is based on placing two planar sensing aluminum film electrodes on the outer side of a poly(methyl methacrylate) (PMMA) microchip (without contacting the solution) and measuring the impedance of the solution in the separation channel. The contactless route obviates problems (e.g., fouling, unwanted reactions) associated with the electrode-solution contact, offers isolation of the detection system from high separation fields, does not compromise the separation efficiency, and greatly simplifies the detector fabrication. Relevant experimental variables, such as the frequency and amplitude of the applied ac voltage or the separation voltage, were examined and optimized. The detector performance was illustrated by the separation of potassium, sodium, barium, and lithium cations and the chloride, sulfate, fluoride, acetate, and phosphate anions. The response was linear (over the 20 microM-7 mM range) and reproducible (RSD = 3.4-4.9%; n = 10), with detection limits of 2.8 and 6.4 microM (for potassium and chloride, respectively). The advantages associated with the contactless conductivity detection, along with the low cost of the integrated PMMA chip/detection system, should enhance the power and scope of microfluidic analytical devices.

  10. Analysis of supercoiled DNA by agarose gel electrophoresis using low-conducting sodium threonine medium.

    PubMed

    Ishido, Tomomi; Ishikawa, Mitsuru; Hirano, Ken

    2010-05-01

    We describe a new low-ionic-strength sodium threonine (STh) medium with the advantage of avoiding relative DNA band migration changes following electrophoresis of supercoiled DNA in agarose gel when substituted for the standard conductive medium of TBE (Tris-boric acid-ethylenediaminetetraacetic acid [EDTA]) or TAE (Tris-acetic acid-EDTA) or the low-ionic-strength sodium boric acid medium. Low-ionic-strength STh medium provided better resolution, less heat generation, and prevention of relative migration order changes among linear, covalently closed circular-, and open circular-formed DNA in the range of 2-10 kilobase pairs in 1% agarose gel electrophoresis.

  11. The Properties of Water in Polymeric Membranes.

    DTIC Science & Technology

    cellulose acetate (CA) membranes have been investigated by magnetic resonance techniques. The data suggest existence in the CA membrane, of two ’types’ of water: a small fraction of highly immobilized ’bound’ water and the remaining large fraction of ’free’ water. The NMR spectra of water adsorbed at various relative humidities on various cellulose ester membranes also have been studied. Membranes of cellulose acetate , triacetate and acetate-butyrate were investigated. The data suggest that the dependence of the

  12. Acetate Kinase Isozymes Confer Robustness in Acetate Metabolism

    PubMed Central

    Chan, Siu Hung Joshua; Nørregaard, Lasse; Solem, Christian; Jensen, Peter Ruhdal

    2014-01-01

    Acetate kinase (ACK) (EC no: 2.7.2.1) interconverts acetyl-phosphate and acetate to either catabolize or synthesize acetyl-CoA dependent on the metabolic requirement. Among all ACK entries available in UniProt, we found that around 45% are multiple ACKs in some organisms including more than 300 species but surprisingly, little work has been done to clarify whether this has any significance. In an attempt to gain further insight we have studied the two ACKs (AckA1, AckA2) encoded by two neighboring genes conserved in Lactococcus lactis (L. lactis) by analyzing protein sequences, characterizing transcription structure, determining enzyme characteristics and effect on growth physiology. The results show that the two ACKs are most likely individually transcribed. AckA1 has a much higher turnover number and AckA2 has a much higher affinity for acetate in vitro. Consistently, growth experiments of mutant strains reveal that AckA1 has a higher capacity for acetate production which allows faster growth in an environment with high acetate concentration. Meanwhile, AckA2 is important for fast acetate-dependent growth at low concentration of acetate. The results demonstrate that the two ACKs have complementary physiological roles in L. lactis to maintain a robust acetate metabolism for fast growth at different extracellular acetate concentrations. The existence of ACK isozymes may reflect a common evolutionary strategy in bacteria in an environment with varying concentrations of acetate. PMID:24638105

  13. Determination of counter-ions in synthetic peptides by ion chromatography, capillary isotachophoresis and capillary electrophoresis.

    PubMed

    Mrozik, Wojciech; Markowska, Aleksandra; Guzik, Lukasz; Kraska, Bartłomiej; Kamysz, Wojciech

    2012-03-01

    The utility of three various analytical techniques [ion chromatography (IC), capillary electrophoresis (CE) and isotachophoresis (ITP)] was tested in the determination of counter-ions in synthetic peptides. The analyzed ions were acetates, trifluoroacetates and chlorides. IC provided the best results; CE, except limit of detection and limit of quantification, exhibited the comparable results. ITP was classified as the less useful because of the problem with the determination of the chloride ions. Nevertheless, all the three techniques were able to analyze trifluoroacetates and acetates ions with satisfactory results. Except analytical methods, three procedures using hydrochloric acid (HCl) (at two different concentrations) and acetic acid as sample solvents processed by lyophilization were tested. It has been found that the lyophilization not only by HCl but also by acetic acid is a simple and cheap procedure for removal of toxic trifluoroacetic counter-ions from peptides on satisfactory levels.

  14. Surface modification in microchip electrophoresis.

    PubMed

    Belder, Detlev; Ludwig, Martin

    2003-11-01

    Different approaches and techniques for surface modification of microfluidic devices applied for microchip electrophoresis are reviewed. The main focus is on the improved electrophoretic separation by reducing analyte-wall interactions and manipulation of electroosmosis. Approaches and methods for permanent and dynamic surface modification of microfluidic devices, manufactured from glass, quartz and also different polymeric substrates, are described.

  15. Microscopic Electrohydrodynamics of DNA electrophoresis

    NASA Astrophysics Data System (ADS)

    Aksimentiev, Aleksei; Luan, Binquan

    2008-03-01

    Gel electrophoresis is currently the most successful yet costly method to sequence DNA. Electrophoresis of DNA through solid-state nanopores holds promise for reducing the costs and making personal genomics a reality. The underlying physics of DNA electrophoresis, however, remains controversial. Theoretical models of this process often invoke the notion of the effective charge of a DNA molecule qeff to account for the reduced electric force on DNA in an external field E, i.e. F= qeffE. However, experimental estimates of qeff can differ from each other by as much as ten times. To clarify the physical origin of the reduction of an electric force on DNA in electrophoresis, we investigated this process through extensive all-atom molecular dynamics simulations. Our results demonstrate that the effective screening of the DNA charge arises from the hydrodynamic drag of the electroosmotic flow, not from the counterion condensation. We show that the effective driving force F of an applied electric field E in a nanopore obeys the same law as in a bulk electrolyte: F=ξμE. Here, ξ and μ are, respectively, the friction coefficient and electrophoretic mobility of DNA that depend on the surface properties of a nanopore, such as its roughness. Based on the above law, a method for determining the effective driving force is suggested that does not require a direct force measurement.

  16. Bioprocessing: Prospects for space electrophoresis

    NASA Technical Reports Server (NTRS)

    Bier, M.

    1977-01-01

    The basic principles of electrophoresis are reviewed in light of its past contributions to biology and medicine. The near-zero gravity environment of orbiting spacecraft may present some unique advantages for a variety of processes, by abolishing the major source of convection in fluids. As the ground-based development of electrophoresis was heavily influenced by the need to circumvent the effects of gravity, this process should be a prime candidate for space operation. Nevertheless, while a space facility for electrophoresis may overcome the limitations imposed by gravity, it will not necessarily overcome all problems inherent in electrophoresis. These are, mainly, electroosmosis and the dissipation of the heat generated by the electric field. The NASA program has already led to excellent coatings to prevent electroosmosis, while the need for heat dissipation will continue to impose limits on the actual size of equipment. It is also not excluded that, once the dominant force of gravity is eliminated, disturbances in fluid stability may originate from weaker forces, such as surface tension.

  17. Gas separation membranes

    DOEpatents

    Schell, William J.

    1979-01-01

    A dry, fabric supported, polymeric gas separation membrane, such as cellulose acetate, is prepared by casting a solution of the polymer onto a shrinkable fabric preferably formed of synthetic polymers such as polyester or polyamide filaments before washing, stretching or calendering (so called griege goods). The supported membrane is then subjected to gelling, annealing, and drying by solvent exchange. During the processing steps, both the fabric support and the membrane shrink a preselected, controlled amount which prevents curling, wrinkling or cracking of the membrane in flat form or when spirally wound into a gas separation element.

  18. The clinical use of PET with 11C-acetate

    PubMed Central

    Grassi, Ilaria; Nanni, Cristina; Allegri, Vincenzo; Morigi, Joshua James; Montini, Gian Carlo; Castellucci, Paolo; Fanti, Stefano

    2012-01-01

    The aim of this review is to evaluate clinical applications of 11C-acetate positron emission tomography (PET). Acetate is quickly metabolized into acetyl-CoA in human cells. In this form it can either enter into the tricarboxylic acid cycle, thus producing energy, as happens in the myocardium, or participate in cell membrane lipid synthesis, as happens in tumor cells. 11C-acetate PET was originally employed in cardiology, to study myocardial oxygen metabolism. More recently it has also been used to evaluate myocardial perfusion, as well as in oncology. The first studies of 11C-acetate focused on its use in prostate cancer. Subsequently, 11C-acetate was studied in other urological malignancies, as well as renal cell carcinoma and bladder cancer. Well differentiated hepatocellular carcinoma represents an 18F-fluoro-deoxyglucose (18F-FDG) PET pitfall, so many authors have proposed to use 11C-acetate in addition to 18F-FDG in studying this tumor. 11C-acetate PET has also been used in other malignancies, such as brain tumors and lung carcinoma. Some authors reported a few cases in which 11C-acetate PET incidentally found multiple myeloma or rare tumors, such as thymoma, multicentric angiomyolipoma of the kidney and cerebellopontine angle schwannoma. Lastly, 11C-acetate PET was also employed in a differential diagnosis case between glioma and encephalitis. The numerous studies on 11C-acetate have demonstrated that it can be used in cardiology and oncology with no contraindications apart from pregnancy and the necessity of a rapid scan. Despite its limited availability, this tracer can surely be considered to be a promising one, because of its versatility and capacity to even detect non 18F-FDG-avid neoplasm, such as differentiated lung cancer or hepatocellular carcinoma. PMID:23133801

  19. Acetal phosphatidic acids: novel platelet aggregating agents.

    PubMed

    Brammer, J P; Maguire, M H; Walaszek, E J; Wiley, R A

    1983-05-01

    induce platelet aggregation per se by direct action at the platelet membrane, and that the acetal function is of primary importance in their potent platelet-stimulating activity. Moreover, as the acetal phosphatidic acids are the major components of the smooth muscle-contracting acidic phospholipid tissue extract ;Darmstoff' (Vogt, 1949), their potent platelet-aggregating properties may be of physiological or pathological significance.

  20. Acetate oxidation by syntrophic association between Geobacter sulfurreducens and a hydrogen-utilizing exoelectrogen.

    PubMed

    Kimura, Zen-ichiro; Okabe, Satoshi

    2013-08-01

    Anodic microbial communities in acetate-fed microbial fuel cells (MFCs) were analyzed using stable-isotope probing of 16S rRNA genes followed by denaturing gradient gel electrophoresis. The results revealed that Geobacter sulfurreducens and Hydrogenophaga sp. predominated in the anodic biofilm. Although the predominance of Geobacter sp. as acetoclastic exoelectrogens in acetate-fed MFC systems has been often reported, the ecophysiological role of Hydrogenophaga sp. is unknown. Therefore, we isolated and characterized a bacterium closely related to Hydrogenophaga sp. (designated strain AR20). The newly isolated strain AR20 could use molecular hydrogen (H2), but not acetate, with carbon electrode as the electron acceptor, indicating that the strain AR20 was a hydrogenotrophic exoelectrogen. This evidence raises a hypothesis that acetate was oxidized by G. sulfurreducens in syntrophic cooperation with the strain AR20 as a hydrogen-consuming partner in the acetate-fed MFC. To prove this hypothesis, G. sulfurreducens strain PCA was cocultivated with the strain AR20 in the acetate-fed MFC without any dissolved electron acceptors. In the coculture MFC of G. sulfurreducens and strain AR20, current generation and acetate degradation were the highest, and the growth of strain AR20 was observed. No current generation, acetate degradation and cell growth occurred in the strain AR20 pure culture MFC. These results show for the first time that G. sulfurreducens can oxidize acetate in syntrophic cooperation with the isolated Hydrogenophaga sp. strain AR20, with electrode as the electron acceptor.

  1. Kallolide A acetate pyrazoline.

    PubMed

    Rodríguez-Escudero, Idaliz; Marrero, Jeffrey; Rodríguez, Abimael D

    2012-01-01

    IN THE CRYSTAL STRUCTURE OF KALLOLIDE A ACETATE PYRAZOLINE [SYSTEMATIC NAME: 7-methyl-16-oxo-4,10-bis-(prop-1-en-2-yl)-17,18-dioxa-14,15-diaza-tetra-cyclo-[9.4.2.1(6,9).0(1,12)]octa-deca-6,8,14-trien-5-yl acetate], C(23)H(28)N(2)O(5), there is a 12-member-ed carbon macrocyclic structure. In addition, there is a tris-ubstituted furan ring, an approximately planar γ-lactone ring [maximum deviation of 0.057 (3) Å] and a pyraz-oline ring, the latter in an envelope conformation. The pyrazoline and the γ-lactone rings are fused in a cis configuration. In the crystal, mol-ecules are linked by weak C-H⋯O inter-actions, forming a two-dimensional network parallel to (001). An intra-molecular C-H⋯O hydrogen bond is also present.

  2. Kallolide A acetate pyrazoline

    PubMed Central

    Rodríguez-Escudero, Idaliz; Marrero, Jeffrey; Rodríguez, Abimael D.

    2012-01-01

    In the crystal structure of kallolide A acetate pyrazoline [systematic name: 7-methyl-16-oxo-4,10-bis­(prop-1-en-2-yl)-17,18-dioxa-14,15-diaza­tetra­cyclo­[9.4.2.16,9.01,12]octa­deca-6,8,14-trien-5-yl acetate], C23H28N2O5, there is a 12-member­ed carbon macrocyclic structure. In addition, there is a tris­ubstituted furan ring, an approximately planar γ-lactone ring [maximum deviation of 0.057 (3) Å] and a pyraz­oline ring, the latter in an envelope conformation. The pyrazoline and the γ-lactone rings are fused in a cis configuration. In the crystal, mol­ecules are linked by weak C—H⋯O inter­actions, forming a two-dimensional network parallel to (001). An intra­molecular C—H⋯O hydrogen bond is also present. PMID:22259545

  3. Techniques For Focusing In Zone Electrophoresis

    NASA Technical Reports Server (NTRS)

    Sharnez, Rizwan; Twitty, Garland E.; Sammons, David W.

    1994-01-01

    In two techniques for focusing in zone electrophoresis, force of applied electrical field in each charged particle balanced by restoring force of electro-osmosis. Two techniques: velocity-gradient focusing (VGF), suitable for rectangular electrophoresis chambers; and field-gradient focusing (FGF), suitable for step-shaped electrophoresis chambers.

  4. Quantification of cholesterol in foods using non-aqueous capillary electrophoresis.

    PubMed

    Xu, Xiao-Hua; Li, Ren-Kuan; Chen, Juan; Chen, Ping; Ling, Xiang-Yang; Rao, Ping-Fan

    2002-03-05

    A simple method for the rapid quantification of cholesterol in egg yolk and milk by non-aqueous capillary electrophoresis (NACE) is described in this paper. The samples were treated with saponification and then quantified by NACE, in which 100 mM sodium acetate-acetic acid in methanol was employed as the running buffer. The correlation coefficient between the cholesterol concentration and the corresponding peak area was 0.999. The detection limit of cholesterol was 5 microg/ml (twice the signal-to-noise ratio). This method can be used as a routine method for the rapid and sensitive determination of cholesterol in foods.

  5. Fast separation and analysis of reduced monoclonal antibodies with capillary zone electrophoresis coupled to mass spectrometry.

    PubMed

    Zhao, Yimeng; Sun, Liangliang; Knierman, Michael D; Dovichi, Norman J

    2016-02-01

    Capillary zone electrophoresis-electrospray ionization-mass spectrometry (CZE-ESI-MS) was used for analysis of reduced antibodies. We first developed a simple protocol to condition commercial linear-polyacrylamide coated capillaries for use in top-down proteomics. We then suspended reduced antibodies in a solution of 35% acetic acid, 50% acetonitrile in water. Heavy and light chains were baseline resolved within 10 min and with 3-30 µg/mL detection limits using a 0.1% aqueous formic acid background electrolyte. Quintuplicate runs of a two-antibody mixture produced relative standard deviations of ∼1% in migration time and 10% in peak amplitudes. Resolution was further improved for the two-antibody mixture by using 5% acetic acid as the background electrolyte, highlighting the potential of capillary electrophoresis-mass spectrometry for analysis of antibody mixtures.

  6. Electrophoresis technology experiment MA-011

    NASA Technical Reports Server (NTRS)

    Allen, R. E.; Barlow, G. H.; Bier, M.; Bigazzi, P. E.; Knox, R. J.; Micale, F. J.; Seaman, G. V. F.; Vanderhoff, J. W.; Vanoss, C. J.; Patterson, W. J.

    1976-01-01

    Experiment MA-011, electrophoresis technology, was designed to test electrophoresis hardware that would continue the development of technology for electrophoretic separation of materials in the near zero g environment of space. The experimental hardware generally functioned as planned. Frozen live cells were successfully transported into space, electrophoretic processing was performed, and viable cells were returned to earth. A separation of the three types of fixed red blood cells (rabbit, human, and horse) was demonstrated. The human lymphocytes, however, showed no apparent migration. The separation of human kidney cells produced the most exciting data. Analysis shows electrophoretic separation throughout the entire column with at least four bands of viable cells. The isotachophoresis experiment definitely demonstrated the isotachophoretic separation of biological cells in a near zero g environment.

  7. Electrophoresis in strong electric fields.

    PubMed

    Barany, Sandor

    2009-01-01

    Two kinds of non-linear electrophoresis (ef) that can be detected in strong electric fields (several hundred V/cm) are considered. The first ("classical" non-linear ef) is due to the interaction of the outer field with field-induced ionic charges in the electric double layer (EDL) under conditions, when field-induced variations of electrolyte concentration remain to be small comparatively to its equilibrium value. According to the Shilov theory, the non-linear component of the electrophoretic velocity for dielectric particles is proportional to the cubic power of the applied field strength (cubic electrophoresis) and to the second power of the particles radius; it is independent of the zeta-potential but is determined by the surface conductivity of particles. The second one, the so-called "superfast electrophoresis" is connected with the interaction of a strong outer field with a secondary diffuse layer of counterions (space charge) that is induced outside the primary (classical) diffuse EDL by the external field itself because of concentration polarization. The Dukhin-Mishchuk theory of "superfast electrophoresis" predicts quadratic dependence of the electrophoretic velocity of unipolar (ionically or electronically) conducting particles on the external field gradient and linear dependence on the particle's size in strong electric fields. These are in sharp contrast to the laws of classical electrophoresis (no dependence of V(ef) on the particle's size and linear dependence on the electric field gradient). A new method to measure the ef velocity of particles in strong electric fields is developed that is based on separation of the effects of sedimentation and electrophoresis using videoimaging and a new flowcell and use of short electric pulses. To test the "classical" non-linear electrophoresis, we have measured the ef velocity of non-conducting polystyrene, aluminium-oxide and (semiconductor) graphite particles as well as Saccharomice cerevisiae yeast cells as a

  8. Ratcheted electrophoresis of Brownian particles

    NASA Astrophysics Data System (ADS)

    Kowalik, Mikołaj; Bishop, Kyle J. M.

    2016-05-01

    The realization of nanoscale machines requires efficient methods by which to rectify unbiased perturbations to perform useful functions in the presence of significant thermal noise. The performance of such Brownian motors often depends sensitively on their operating conditions—in particular, on the relative rates of diffusive and deterministic motions. In this letter, we present a type of Brownian motor that uses contact charge electrophoresis of a colloidal particle within a ratcheted channel to achieve directed transport or perform useful work against an applied load. We analyze the stochastic dynamics of this model ratchet to show that it functions under any operating condition—even in the limit of strong thermal noise and in contrast to existing ratchets. The theoretical results presented here suggest that ratcheted electrophoresis could provide a basis for electrochemically powered, nanoscale machines capable of transport and actuation of nanoscale components.

  9. Characterization of acetate transport in colorectal cancer cells and potential therapeutic implications

    PubMed Central

    Ferro, Suellen; Azevedo-Silva, João; Casal, Margarida; Côrte-Real, Manuela; Baltazar, Fatima; Preto, Ana

    2016-01-01

    Acetate, together with other short chain fatty acids has been implicated in colorectal cancer (CRC) prevention/therapy. Acetate was shown to induce apoptosis in CRC cells. The precise mechanism underlying acetate transport across CRC cells membrane, that may be implicated in its selectivity towards CRC cells, is not fully understood and was addressed here. We also assessed the effect of acetate in CRC glycolytic metabolism and explored its use in combination with the glycolytic inhibitor 3-bromopyruvate (3BP). We provide evidence that acetate enters CRC cells by the secondary active transporters MCT1 and/or MCT2 and SMCT1 as well as by facilitated diffusion via aquaporins. CRC cell exposure to acetate upregulates the expression of MCT1, MCT4 and CD147, while promoting MCT1 plasma membrane localization. We also observed that acetate increases CRC cell glycolytic phenotype and that acetate-induced apoptosis and anti-proliferative effect was potentiated by 3BP. Our data suggest that acetate selectivity towards CRC cells might be explained by the fact that aquaporins and MCTs are found overexpressed in CRC clinical cases. Our work highlights the importance that acetate transport regulation has in the use of drugs such as 3BP as a new therapeutic strategy for CRC. PMID:27661124

  10. Enhancing Centrifugal Separation With Electrophoresis

    NASA Technical Reports Server (NTRS)

    Herrmann, F. T.

    1986-01-01

    Separation of biological cells by coil-planet centrifuge enhanced by electrophoresis. By itself, coil-planet centrifuge offers relatively gentle method of separating cells under low centrifugal force in physiological medium that keeps cells alive. With addition of voltage gradient to separation column of centrifuge, separation still gentle but faster and more complete. Since separation apparatus contains no rotary seal, probability of leakage, contamination, corrosion, and short circuits reduced.

  11. Capillary electrophoresis systems and methods

    DOEpatents

    Dorairaj, Rathissh; Keynton, Robert S.; Roussel, Thomas J.; Crain, Mark M.; Jackson, Douglas J.; Walsh, Kevin M.; Naber, John F.; Baldwin, Richard P.; Franco, Danielle B.

    2011-08-02

    An embodiment of the invention is directed to a capillary electrophoresis apparatus comprising a plurality of separation micro-channels. A sample loading channel communicates with each of the plurality of separation channels. A driver circuit comprising a plurality of electrodes is configured to induce an electric field across each of the plurality of separation channels sufficient to cause analytes in the samples to migrate along each of the channels. The system further comprises a plurality of detectors configured to detect the analytes.

  12. Membranes and Films from Polymers.

    ERIC Educational Resources Information Center

    Blumberg, Avrom A.

    1986-01-01

    Provides background information on polymeric films and membranes including production methods, special industrial and medical applications, laboratory preparation, and an experimental investigation of a porous cellulose acetate membrane. Presents a demonstration to distinguish between high- and low-density polyethylene. (JM)

  13. Capillary Electrophoresis - Optical Detection Systems

    SciTech Connect

    Sepaniak, M. J.

    2001-08-06

    Molecular recognition systems are developed via molecular modeling and synthesis to enhance separation performance in capillary electrophoresis and optical detection methods for capillary electrophoresis. The underpinning theme of our work is the rational design and development of molecular recognition systems in chemical separations and analysis. There have been, however, some subtle and exciting shifts in our research paradigm during this period. Specifically, we have moved from mostly separations research to a good balance between separations and spectroscopic detection for separations. This shift is based on our perception that the pressing research challenges and needs in capillary electrophoresis and electrokinetic chromatography relate to the persistent detection and flow rate reproducibility limitations of these techniques (see page 1 of the accompanying Renewal Application for further discussion). In most of our work molecular recognition reagents are employed to provide selectivity and enhance performance. Also, an emerging trend is the use of these reagents with specially-prepared nano-scale materials. Although not part of our DOE BES-supported work, the modeling and synthesis of new receptors has indirectly supported the development of novel microcantilevers-based MEMS for the sensing of vapor and liquid phase analytes. This fortuitous overlap is briefly covered in this report. Several of the more significant publications that have resulted from our work are appended. To facilitate brevity we refer to these publications liberally in this progress report. Reference is also made to very recent work in the Background and Preliminary Studies Section of the Renewal Application.

  14. Membrane humidity control investigation

    NASA Technical Reports Server (NTRS)

    Elam, J.; Ruder, J.; Strumpf, H.

    1974-01-01

    The basic performance data on a hollow fiber membrane unit that removes water from a breathing gas loop by diffusion is presented. Using available permeability data for cellulose acetate, a preliminary design was made of a dehumidifier unit that would meet the problem statement.

  15. Ethanol sorption and partial molar volume in cellulose acetate films

    SciTech Connect

    Bolton, B.A.; Kint, S.; Bailey, G.F.; Scherer, J.R.

    1986-03-13

    The absorption characteristics of cellulose acetate (CA398) and cellulose triacetate membranes for ethanol vapor were determined by integrated optical techniques. Changes in the refractive index and film thicknesses are used to calculate the ethanol concentration within the membrane, to calculate the partial molar volume of sorbed ethanol as a function of ethanol concentration, and to estimate the average void volume of the dry film. The refractive index is shown to be very sensitive to the available void space within the membrane. The average total void space for the films considered here was less than 1% of the dry polymer volume. 22 references, 6 figures, 1 table.

  16. Mathematical models of continuous flow electrophoresis: Electrophoresis technology

    NASA Technical Reports Server (NTRS)

    Saville, Dudley A.

    1986-01-01

    Two aspects of continuous flow electrophoresis were studied: (1) the structure of the flow field in continuous flow devices; and (2) the electrokinetic properties of suspended particles relevant to electrophoretic separations. Mathematical models were developed to describe flow structure and stability, with particular emphasis on effects due to buoyancy. To describe the fractionation of an arbitrary particulate sample by continuous flow electrophoresis, a general mathematical model was constructed. In this model, chamber dimensions, field strength, buffer composition, and other design variables can be altered at will to study their effects on resolution and throughput. All these mathematical models were implemented on a digital computer and the codes are available for general use. Experimental and theoretical work with particulate samples probed how particle mobility is related to buffer composition. It was found that ions on the surface of small particles are mobile, contrary to the widely accepted view. This influences particle mobility and suspension conductivity. A novel technique was used to measure the mobility of particles in concentrated suspensions.

  17. Microchip electrophoresis for chiral separations.

    PubMed

    Belder, Detlev; Ludwig, Martin

    2003-08-01

    Microchip electrophoresis (MCE) is a promising new technique for the separation of enantiomers. This recently introduced technique enables chiral separations to be performed in seconds on tiny micromachined devices. This review is intended to give a brief introduction into the principles of chiral separations with MCE with regard to methodology and instrumentation. Different approaches to realize chiral separations in microfluidic devices are described and discussed. This review gives an overview of original work done in this field with emphasis on approaches to improve detection and resolution in chiral MCE.

  18. Integrated multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, Edward S.; Tan, Hongdong

    2002-05-14

    The present invention provides an integrated multiplexed capillary electrophoresis system for the analysis of sample analytes. The system integrates and automates multiple components, such as chromatographic columns and separation capillaries, and further provides a detector for the detection of analytes eluting from the separation capillaries. The system employs multiplexed freeze/thaw valves to manage fluid flow and sample movement. The system is computer controlled and is capable of processing samples through reaction, purification, denaturation, pre-concentration, injection, separation and detection in parallel fashion. Methods employing the system of the invention are also provided.

  19. Non-aqueous capillary electrophoresis of drugs: properties and application of selected solvents.

    PubMed

    Tjørnelund, J; Hansen, S H

    1999-01-29

    The electrophoretic mobility of selected acidic and basic test solutes have been determined in non-aqueous media prepared by adding various combinations of ammonium acetate, sodium acetate, methane sulphonic acid and acetic acid to acetonitrile, propylene carbonate, methanol, formamide, N-methylformamide, N,N-dimethylformamide and dimethylsulphoxide, respectively. The apparent pH (pH*) of these non-aqueous media have been measured and it was found that pH* is an important factor for the separations in non-aqueous capillary electrophoresis. However, in some solvents the concentration of sodium acetate has a strong influence on the mobility despite very small changes in pH*. Due to the fact that a change in one parameter influences a number of other parameters it is very difficult to conduct systematic studies in non-aqueous media and to compare the migration of the species at fixed pH* values from one solvent to another. Thus pH* is only of value for comparison when used with a specific solvent or solvent mixture. The viscosity of the above-mentioned solvents were measured at various temperatures and means to adjust the viscosity of the non-aqueous media used for capillary electrophoresis are discussed and the separation of ibuprofen and its major metabolites in urine is used as an example.

  20. Properties of nucleic acid staining dyes used in gel electrophoresis.

    PubMed

    Haines, Alicia M; Tobe, Shanan S; Kobus, Hilton J; Linacre, Adrian

    2015-03-01

    Nucleic acid staining dyes are used for detecting nucleic acids in electrophoresis gels. Historically, the most common dye used for gel staining is ethidium bromide, however due to its toxicity and mutagenicity other dyes that are safer to the user and the environment are preferred. This Short Communication details the properties of dyes now available and their sensitivity for detection of DNA and their ability to permeate the cell membrane. It was found that GelRed™ was the most sensitive and safest dye to use with UV light excitation, and both GelGreen™ and Diamond™ Nucleic Acid Dye were sensitive and the safer dyes using blue light excitation.

  1. Regulation of membrane associated protein kinase C activity by guanine nucleotide in rabbit peritoneal neutrophils

    SciTech Connect

    Huang, C.K.; Devanney, J.F.

    1986-03-05

    Addition of phorbol myristate acetate (PMA) (0.1 ..mu..g/ml) or guanosine-5'-0-(3-thiotriphosphate) (GTP..gamma..S) (10..mu..M) to the membrane fraction from rabbit peritoneal neutrophils results in an increase of phosphorylation of several membrane proteins. To test whether membrane associated protein kinase C is involved in the activation, histone is added to the membrane as a substrate for protein kinase C. Phosphorylation of histone is determined by counting the gel pieces containing histone IIIS after separation from other membrane components by SDS-gel electrophoresis. In the presence of CaC12 (20 ..mu..M), GTP..gamma..S (10 ..mu..M) or PMA (0.1 ..mu..g/ml) stimulates the phosphorylation of histone IIIS (40% to 70% increase). To achieve this effect calcium is required for GTP..gamma..S but not for PMA. The effect of GTP..gamma..S but not PMA is inhibited in membranes obtained from cells pretreated with pertussis toxin. Membrane protein kinase C is solubilized with Triton X-100 (1%) and then applied to a DEAE-52 cellulose column chromatography. Two peaks of protein kinase C activity are observed. Peak one is eluted at 40 mM NaCl, peak two is eluted at 140 mM NaCl. The activity of peak one is stimulated with phosphatidylserine (PS) and PMA but not with PS and calcium. The activity of peak two is stimulated with either PS and PMA or PS and calcium. The results suggest that GTP binding protein is involved in the activation of membrane associated protein kinase C and the kinase may exist in two forms, calcium sensitive and calcium insensitive.

  2. 21 CFR 184.1185 - Calcium acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .... No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be produced by the calcium hydroxide neutralization of acetic acid. (b) The ingredient meets...

  3. 21 CFR 184.1185 - Calcium acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .... No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be produced by the calcium hydroxide neutralization of acetic acid. (b) The ingredient meets...

  4. 21 CFR 184.1185 - Calcium acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be produced by the calcium hydroxide neutralization of acetic acid. (b) The ingredient meets...

  5. 21 CFR 184.1185 - Calcium acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be produced by the calcium hydroxide neutralization of acetic acid. (b) The ingredient meets the specifications of the...

  6. Scaleable production and separation of fermentation-derived acetic acid. Final CRADA report.

    SciTech Connect

    Snyder, S. W.; Energy Systems

    2010-02-08

    Half of U.S. acetic acid production is used in manufacturing vinyl acetate monomer (VAM) and is economical only in very large production plants. Nearly 80% of the VAM is produced by methanol carbonylation, which requires high temperatures and exotic construction materials and is energy intensive. Fermentation-derived acetic acid production allows for small-scale production at low temperatures, significantly reducing the energy requirement of the process. The goal of the project is to develop a scaleable production and separation process for fermentation-derived acetic acid. Synthesis gas (syngas) will be fermented to acetic acid, and the fermentation broth will be continuously neutralized with ammonia. The acetic acid product will be recovered from the ammonium acid broth using vapor-based membrane separation technology. The process is summarized in Figure 1. The two technical challenges to success are selecting and developing (1) microbial strains that efficiently ferment syngas to acetic acid in high salt environments and (2) membranes that efficiently separate ammonia from the acetic acid/water mixture and are stable at high enough temperature to facilitate high thermal cracking of the ammonium acetate salt. Fermentation - Microbial strains were procured from a variety of public culture collections (Table 1). Strains were incubated and grown in the presence of the ammonium acetate product and the fastest growing cultures were selected and incubated at higher product concentrations. An example of the performance of a selected culture is shown in Figure 2. Separations - Several membranes were considered. Testing was performed on a new product line produced by Sulzer Chemtech (Germany). These are tubular ceramic membranes with weak acid functionality (see Figure 3). The following results were observed: (1) The membranes were relatively fragile in a laboratory setting; (2) Thermally stable {at} 130 C in hot organic acids; (3) Acetic acid rejection > 99%; and (4

  7. Pallidol hexa­acetate ethyl acetate monosolvate

    PubMed Central

    Mao, Qinyong; Taylor, Dennis K.; Ng, Seik Weng; Tiekink, Edward R. T.

    2013-01-01

    The entire mol­ecule of pallidol hexa­acetate {systematic name: (±)-(4bR,5R,9bR,10R)-5,10-bis­[4-(acet­yloxy)phen­yl]-4b,5,9b,10-tetra­hydro­indeno­[2,1-a]indene-1,3,6,8-tetrayl tetra­acetate} is completed by the application of twofold rotational symmetry in the title ethyl acetate solvate, C40H34O12·C4H8O2. The ethyl acetate mol­ecule was highly disordered and was treated with the SQUEEZE routine [Spek (2009 ▶). Acta Cryst. D65, 148–155]; the crystallographic data take into account the presence of the solvent. In pallidol hexa­acetate, the dihedral angle between the fused five-membered rings (r.m.s. deviation = 0.100 Å) is 54.73 (6)°, indicating a significant fold in the mol­ecule. Significant twists between residues are also evident as seen in the dihedral angle of 80.70 (5)° between the five-membered ring and the pendent benzene ring to which it is attached. Similarly, the acetate residues are twisted with respect to the benzene ring to which they are attached [C—O(carb­oxy)—C—C torsion angles = −70.24 (14), −114.43 (10) and −72.54 (13)°]. In the crystal, a three-dimensional architecture is sustained by C—H⋯O inter­actions which encompass channels in which the disordered ethyl acetate mol­ecules reside. PMID:24046702

  8. Conducting polymer electrodes for gel electrophoresis.

    PubMed

    Bengtsson, Katarina; Nilsson, Sara; Robinson, Nathaniel D

    2014-01-01

    In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that π-conjugated polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis) systems. In this report, we extend our previous result to gel electrophoresis, and show that electrodes containing PEDOT can be used with a commercial polyacrylamide gel electrophoresis system with minimal impact to the resulting gel image or the ionic transport measured during a separation.

  9. Capillary electrophoresis for drug analysis

    NASA Astrophysics Data System (ADS)

    Lurie, Ira S.

    1999-02-01

    Capillary electrophoresis (CE) is a high resolution separation technique which is amenable to a wide variety of solutes, including compounds which are thermally degradable, non-volatile and highly polar, and is therefore well suited for drug analysis. Techniques which have been used in our laboratory include electrokinetic chromatography (ECC), free zone electrophoresis (CZE) and capillary electrochromatography (CEC). ECC, which uses a charged run buffer additive which migrates counter to osmotic flow, is excellent for many applications, including, drug screening and analyses of heroin, cocaine and methamphetamine samples. ECC approaches include the use of micelles and charged cyclodextrins, which allow for the separation of complex mixtures. Simultaneous separation of acidic, neutral and basic solutes and the resolution of optical isomers and positional isomers are possible. CZE has been used for the analysis of small ions (cations and anions) in heroin exhibits. For the ECC and CZE experiments performed in our laboratory, uncoated capillaries were used. In contrast, CEC uses capillaries packed with high performance liquid chromatography stationary phases, and offers both high peak capacities and unique selectivities. Applications include the analysis of cannabinoids and drug screening. Although CE suffers from limited concentration sensitivity, it is still applicable to trace analysis of drug samples, especially when using injection techniques such as stacking, or detection schemes such as laser induced fluorescence and extended pathlength UV.

  10. Tris-acetate polyacrylamide gradient gels for the simultaneous electrophoretic analysis of proteins of very high and low molecular mass.

    PubMed

    Cubillos-Rojas, Monica; Amair-Pinedo, Fabiola; Tato, Irantzu; Bartrons, Ramon; Ventura, Francesc; Rosa, Jose Luis

    2012-01-01

    Polyacrylamide gel electrophoresis (PAGE) is one of the most powerful tools used for protein analysis. We describe the use of Tris-acetate buffer and 3-15% polyacrylamide gradient gels to simultaneously separate proteins in the mass range of 10-500 kDa. We show that this system is highly sensitive, it has good resolution and high reproducibility, and that it can be used for general applications of PAGE such as Coomassie Brilliant Blue staining and immunoblotting. Moreover, we describe how to generate mini Tris-acetate polyacrylamide gels to use them in miniprotein electrophoresis systems. These economical gels are easy to generate and to manipulate and allow a rapid analysis of proteins. All these features make the Tris-acetate-PAGE system a very helpful tool for protein analysis.

  11. Electrophoresis-mass spectrometry probe

    DOEpatents

    Andresen, Brian D.; Fought, Eric R.

    1987-01-01

    The invention involves a new technique for the separation of complex mixtures of chemicals, which utilizes a unique interface probe for conventional mass spectrometers which allows the electrophoretically separated compounds to be analyzed in real-time by a mass spectrometer. This new chemical analysis interface, which couples electrophoresis with mass spectrometry, allows complex mixtures to be analyzed very rapidly, with much greater specificity, and with greater sensitivity. The interface or probe provides a means whereby large and/or polar molecules in complex mixtures to be completely characterized. The preferred embodiment of the probe utilizes a double capillary tip which allows the probe tip to be continually wetted by the buffer, which provides for increased heat dissipation, and results in a continually operating interface which is more durable and electronically stable than the illustrated single capillary tip probe interface.

  12. Electrophoresis-mass spectrometry probe

    DOEpatents

    Andresen, B.D.; Fought, E.R.

    1987-11-10

    The invention involves a new technique for the separation of complex mixtures of chemicals, which utilizes a unique interface probe for conventional mass spectrometers which allows the electrophoretically separated compounds to be analyzed in real-time by a mass spectrometer. This new chemical analysis interface, which couples electrophoresis with mass spectrometry, allows complex mixtures to be analyzed very rapidly, with much greater specificity, and with greater sensitivity. The interface or probe provides a means whereby large and/or polar molecules in complex mixtures to be completely characterized. The preferred embodiment of the probe utilizes a double capillary tip which allows the probe tip to be continually wetted by the buffer, which provides for increased heat dissipation, and results in a continually operating interface which is more durable and electronically stable than the illustrated single capillary tip probe interface. 8 figs.

  13. Non-Aqueous Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

    Szumski, Michał; Buszewski, Bogusław

    Non-aqueous capillary electrophoresis and capillary electrochromatography are special variants of these techniques. Here, organic solvents or their mixtures with or without dissolved electrolytes are used as separation buffer or mobile phase, respectively. The most important features of non-aqueous systems are: better solubility of more hydrophobic ionic substances (many natural products) than in water, much less current and Joule heating allows for using highly concentrated buffers and/or larger capillary internal diameters, polar interactions are enhanced in organic solvents which is often highly advantageous in chiral separation systems. This chapter presents most frequently used solvents, their properties, as well as shows pH* scale which is often used in non-aqueous systems.

  14. Compensating for Electro-Osmosis in Electrophoresis

    NASA Technical Reports Server (NTRS)

    Rhodes, Percy H.; Snyder, Robert S.

    1987-01-01

    Simple mechanical adjustment eliminates transverse velocity component. New apparatus for moving-wall electrophoresis increases degree of collimation of chemical species in sample stream. Electrophoresis chamber set at slight angle in horizontal plane to adjust angle between solution flow and wall motion. Component of velocity created cancels electro-osmotic effect.

  15. Fluorescence detection for gel and capillary electrophoresis

    SciTech Connect

    Hogan, B.

    1992-07-21

    First, an indirect fluorescence detection system for the separation of proteins via gel electrophoresis. Quantities as low as 50 nanograms of bovine serum albumin and soybean trypsin inhibitor are separated and detected visually without the need for staining of the analytes. This is very similar to levels of protein commonly separated with gel electrophoresis.

  16. Getting the Most out of Electrophoresis Units

    ERIC Educational Resources Information Center

    Mulvihill, Charlotte

    2007-01-01

    At Oklahoma City Community College, they have developed gel electrophoresis activities that support active learning of many scientific concepts, including: pH, electrolysis, oxidation reduction, electrical currents, potentials, conductivity, molarity, gel electrophoresis, DNA and protein separation, and DNA fingerprinting. This article presents…

  17. Two Electrophoresis Experiments for Freshmen in the Health Professions.

    ERIC Educational Resources Information Center

    Brabson, G. Dana; Waugh, David S.

    1986-01-01

    Describes procedures involved with paper electrophoresis separation of amino acids, gel electrophoresis separation of DNA, and design of an electrophoresis tank. Describes experiments using paper (amino acids) and gel (deoxyribonucleic acid fragments). Provides material lists, procedures, and discussion. (JM)

  18. An evaluation of the SPIFE 3000 semi-automated gel electrophoresis system for the identification of hemoglobin variants and comparison of relative electrophoretic mobilities with manual gel electrophoresis methods.

    PubMed

    Hoyer, J D; Markley, K M; Savedra, M E; Kubik, K S; Scheidt, R M

    2010-06-01

    Laboratory identification of hemoglobin (Hb) variants can involve multiple techniques. The use of semi-automated instruments that perform gel electrophoresis and staining, such as the SPIFE 3000 electrophoresis system, can greatly reduce the labor required for these commonly used techniques. We performed a comparison of the method involved in SPIFE 3000 system with those of manual gel electrophoresis. A total of 22 540 samples were analyzed using the SPIFE 3000, and compared with mobilities on cellulose acetate and citrate agar gels using standard manual methods. The results were compared using relative electrophoretic mobilities (REM). Of the 191 Hb variants identified, only 13 had REM that differed from manual electrophoresis when analyzed using the SPIFE 3000 system. One variant (Hb O-Indonesia) showed different mobility on both acid and alkaline gels, two (Hb E, Hb Sunshine Seth) on alkaline gel only, and 10 (Hbs N-Baltimore, N-Seattle, O-Arab, Shelby, Summer Hill, Tak, Hasharon, M-Iwate, Q-Iran, and Setif) on acid gels only. The SPIFE 3000 semi-automated electrophoresis system produces similar results when compared with those of standard manual electrophoresis methods.

  19. DNA Sequencing Using capillary Electrophoresis

    SciTech Connect

    Dr. Barry Karger

    2011-05-09

    The overall goal of this program was to develop capillary electrophoresis as the tool to be used to sequence for the first time the Human Genome. Our program was part of the Human Genome Project. In this work, we were highly successful and the replaceable polymer we developed, linear polyacrylamide, was used by the DOE sequencing lab in California to sequence a significant portion of the human genome using the MegaBase multiple capillary array electrophoresis instrument. In this final report, we summarize our efforts and success. We began our work by separating by capillary electrophoresis double strand oligonucleotides using cross-linked polyacrylamide gels in fused silica capillaries. This work showed the potential of the methodology. However, preparation of such cross-linked gel capillaries was difficult with poor reproducibility, and even more important, the columns were not very stable. We improved stability by using non-cross linked linear polyacrylamide. Here, the entangled linear chains could move when osmotic pressure (e.g. sample injection) was imposed on the polymer matrix. This relaxation of the polymer dissipated the stress in the column. Our next advance was to use significantly lower concentrations of the linear polyacrylamide that the polymer could be automatically blown out after each run and replaced with fresh linear polymer solution. In this way, a new column was available for each analytical run. Finally, while testing many linear polymers, we selected linear polyacrylamide as the best matrix as it was the most hydrophilic polymer available. Under our DOE program, we demonstrated initially the success of the linear polyacrylamide to separate double strand DNA. We note that the method is used even today to assay purity of double stranded DNA fragments. Our focus, of course, was on the separation of single stranded DNA for sequencing purposes. In one paper, we demonstrated the success of our approach in sequencing up to 500 bases. Other

  20. Acid diffusion through polyaniline membranes

    SciTech Connect

    Su, T.M.; Huang, S.C.; Conklin, J.A.

    1995-12-01

    Polyaniline membranes in the undoped (base) and doped (acid) forms are studied for their utility as pervaporation membranes. The separation of water from mixtures of propionic acid, acetic acid and formic acid have been demonstrated from various feed compositions. Doped polyaniline displays an enhanced selectivity of water over these organic acids as compared with undoped polyaniline. For as-cast polyaniline membranes a diffusion coefficient (D) on the order of 10{sup -9} cm{sup 2}/sec has been determined for the flux of protons through the membranes using hydrochloric acid.

  1. Micelles Protect and Concentrate Activated Acetic Acid

    NASA Astrophysics Data System (ADS)

    Todd, Zoe; House, C.

    2014-01-01

    As more and more exoplanets are discovered and the habitability of such planets is considered, one can turn to searching for the origin of life on Earth in order to better understand what makes a habitable planet. Activated acetic acid, or methyl thioacetate, has been proposed to be central to the origin of life on Earth, and also as an important energy currency molecule in early cellular evolution. We have investigated the hydrolysis of methyl thioacetate under various conditions. Its uncatalyzed rate of hydrolysis is about three orders of magnitude faster (K = 0.00663 s^-1; 100°C, pH 7.5, concentration = 0.33mM) than published rates for its catalyzed production making it unlikely to accumulate under prebiotic conditions. However, we also observed that methyl thioacetate was protected from hydrolysis when inside its own hydrophobic droplets. We found that methyl thioacetate protection from hydrolysis was also possible in droplets of hexane and in the membranes of nonanoic acid micelles. Thus, the hydrophobic regions of prebiotic micelles and early cell membranes could have offered a refuge for this energetic molecule increasing its lifetime in close proximity to the reactions for which it would be needed. Methyl thioacetate could thus be important for the origin of life on Earth and perhaps for better understanding the potential habitability of other planets.

  2. Electrophoresis in space at zero gravity

    NASA Technical Reports Server (NTRS)

    Bier, M.; Snyder, R. S.

    1974-01-01

    Early planning for manufacturing operations in space include the use of electrophoresis for purification and separation of biological materials. Greatly simplified electrophoresis apparatus have been flown in the Apollo 14 and 16 missions to test the possibility of stable liquid systems in orbit. Additionally, isoelectric focusing and isotachophoresis are of particular interest as they offer very high resolution and have self-sharpening boundaries. The value of possible space electrophoresis is substantial. For example, present technology permits large fractionation of only a few of blood proteins many fractions, and separated cell populations are needed for research.

  3. Proteins causing membrane fouling in membrane bioreactors.

    PubMed

    Miyoshi, Taro; Nagai, Yuhei; Aizawa, Tomoyasu; Kimura, Katsuki; Watanabe, Yoshimasa

    2015-01-01

    In this study, the details of proteins causing membrane fouling in membrane bioreactors (MBRs) treating real municipal wastewater were investigated. Two separate pilot-scale MBRs were continuously operated under significantly different operating conditions; one MBR was a submerged type whereas the other was a side-stream type. The submerged and side-stream MBRs were operated for 20 and 10 days, respectively. At the end of continuous operation, the foulants were extracted from the fouled membranes. The proteins contained in the extracted foulants were enriched by using the combination of crude concentration with an ultrafiltration membrane and trichloroacetic acid precipitation, and then separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). The N-terminal amino acid sequencing analysis of the proteins which formed intensive spots on the 2D-PAGE gels allowed us to partially identify one protein (OmpA family protein originated from genus Brevundimonas or Riemerella anatipestifer) from the foulant obtained from the submerged MBR, and two proteins (OprD and OprF originated from genus Pseudomonas) from that obtained from the side-stream MBR. Despite the significant difference in operating conditions of the two MBRs, all proteins identified in this study belong to β-barrel protein. These findings strongly suggest the importance of β-barrel proteins in developing membrane fouling in MBRs.

  4. Phenomenology of colloidal crystal electrophoresis

    NASA Astrophysics Data System (ADS)

    Medebach, Martin; Palberg, Thomas

    2003-08-01

    We studied the motion of polycrystalline solids comprising of charged sub-micron latex spheres suspended in deionized water. These were subjected to a low frequency alternating square wave electric field in an optical cell of rectangular cross section. Velocity profiles in X and Y direction were determined by Laser Doppler Velocimetry. The observed complex flow profiles are time dependent due to the combined effects of electro-osmosis, electrophoresis, crystal elasticity, and friction of the crystals at the cell wall. On small time scales elastic deformation occurs. On long time scales channel formation is observed. At intermediate times steady state profiles are dominated by a solid plug of polycrystalline material moving in the cell center. At large field strengths the plug shear melts. Mobilities in the shear molten state are on the order of (6.5±0.5) 10-8 m2 V-1 s-1 and connect continuously with those of the equilibrium fluid. The apparent mobility of the plug is much larger than of the fluid and like the mobility of the fluid decreases with increasing particle number density. We qualitatively attribute the accelerated motion of the plug to an incomplete exposure to the electro-osmotic flow profile.

  5. Atomic Force Controlled Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

    Lewis, Aaron; Yeshua, Talia; Palchan, Mila; Lovsky, Yulia; Taha, Hesham

    2010-03-01

    Lithography based on scanning probe microscopic techniques has considerable potential for accurate & localized deposition of material on the nanometer scale. Controlled deposition of metallic features with high purity and spatial accuracy is of great interest for circuit edit applications in the semiconductor industry, for plasmonics & nanophotonics and for basic research in surface enhanced Raman scattering & nanobiophysics. Within the context of metal deposition we will review the development of fountain pen nanochemistry and its most recent emulation Atomic Force Controlled Capillary Electrophoresis (ACCE). Using this latter development we will demonstrate achievement of unprecedented control of nanoparticle deposition using a three-electrode geometry. Three electrodes are attached: one on the outside of a metal coated glass probe, one on the inside of a hollow probe in a solution containing Au nanoparticles in the capillary, and a third on the surface where the writing takes place. The three electrodes provide electrical pulses for accurate control of deposition and retraction of the liquid from the surface overcoming the lack of control seen in both dip pen lithography & fountain pen nanochemistry when the tip contacts the surface. With this development, we demonstrate depositing a single 1.3 nm Au nanoparticle onto surfaces such as semiconductors.

  6. Plant uses membrane separation

    SciTech Connect

    Yamashiro, H.; Hirajo, M.; Maitland, C.F.; Schell, W.J.

    1985-02-01

    Cellulose acetate membranes exhibit long-time stability in refinery H/sub 2/ recovery applications even under harsh operating conditions. High performance has been achieved at temperatures as great as 82/sup 0/ C while in the presence of benzene, toluene, xylene and other heavy hydrocarbons. In addition, constant values for selectivity and permeation rate have been obtained under a variety of pressure ratios and flowrates. Successful operation of this system demonstrates the commercial capability of such membranes for hydrogen recovery applications. One of the most practical applications for membranes is in recovery and purification of hydrogen from fuel gases. As hydrogen is an expensive chemical feedstock in hydrogen refining, the attendant reduction in hydrogen supply needs from outside sources is of considerable interest. In addition, installation of a membrane system can satisfy increasing need for more hydrogen as more sour and heavy crude oils are processed. Commercial use of cellulose acetate membranes for this application has been demonstrated on a reformer off-gas stream in the Chiba Refinery of the Cosmo Oil Co. in Japan. The system has been operating since October 1983, processing approximately 1,000 Nm/sup 3//h of 80% H/sub 2/ off-gas. Operating conditions are very severe due to the presence of aromatic hydrocarbons in the gas stream, thus successful testing is particularly noteworthy.

  7. Dual Electrophoresis Detection System for Rapid and Sensitive Immunoassays with Nanoparticle Signal Amplification

    NASA Astrophysics Data System (ADS)

    Zhang, Fangfang; Ma, Junjie; Watanabe, Junji; Tang, Jinlong; Liu, Huiyu; Shen, Heyun

    2017-02-01

    An electrophoretic technique was combined with an enzyme-linked immunosorbent assay (ELISA) system to achieve a rapid and sensitive immunoassay. A cellulose acetate filter modified with polyelectrolyte multilayer (PEM) was used as a solid substrate for three-dimensional antigen-antibody reactions. A dual electrophoresis process was used to induce directional migration and local condensation of antigens and antibodies at the solid substrate, avoiding the long diffusion times associated with antigen-antibody reactions in conventional ELISAs. The electrophoretic forces drove two steps in the ELISA process, namely the adsorption of antigen, and secondary antibody-labelled polystyrene nanoparticles (NP-Ab). The total time needed for dual electrophoresis-driven detection was just 4 min, nearly 2 h faster than a conventional ELISA system. Moreover, the rapid NP-Ab electrophoresis system simultaneously achieved amplification of the specific signal and a reduction in noise, leading to a more sensitive NP-Ab immunoassay with a limit of detection (LOD) of 130 fM, and wide range of detectable concentrations from 0.13 to 130 pM. These results suggest that the combination of dual electrophoresis detection and NP-Ab signal amplification has great potential for future immunoassay systems.

  8. Dual Electrophoresis Detection System for Rapid and Sensitive Immunoassays with Nanoparticle Signal Amplification.

    PubMed

    Zhang, Fangfang; Ma, Junjie; Watanabe, Junji; Tang, Jinlong; Liu, Huiyu; Shen, Heyun

    2017-02-15

    An electrophoretic technique was combined with an enzyme-linked immunosorbent assay (ELISA) system to achieve a rapid and sensitive immunoassay. A cellulose acetate filter modified with polyelectrolyte multilayer (PEM) was used as a solid substrate for three-dimensional antigen-antibody reactions. A dual electrophoresis process was used to induce directional migration and local condensation of antigens and antibodies at the solid substrate, avoiding the long diffusion times associated with antigen-antibody reactions in conventional ELISAs. The electrophoretic forces drove two steps in the ELISA process, namely the adsorption of antigen, and secondary antibody-labelled polystyrene nanoparticles (NP-Ab). The total time needed for dual electrophoresis-driven detection was just 4 min, nearly 2 h faster than a conventional ELISA system. Moreover, the rapid NP-Ab electrophoresis system simultaneously achieved amplification of the specific signal and a reduction in noise, leading to a more sensitive NP-Ab immunoassay with a limit of detection (LOD) of 130 fM, and wide range of detectable concentrations from 0.13 to 130 pM. These results suggest that the combination of dual electrophoresis detection and NP-Ab signal amplification has great potential for future immunoassay systems.

  9. Dual Electrophoresis Detection System for Rapid and Sensitive Immunoassays with Nanoparticle Signal Amplification

    PubMed Central

    Zhang, Fangfang; Ma, Junjie; Watanabe, Junji; Tang, Jinlong; Liu, Huiyu; Shen, Heyun

    2017-01-01

    An electrophoretic technique was combined with an enzyme-linked immunosorbent assay (ELISA) system to achieve a rapid and sensitive immunoassay. A cellulose acetate filter modified with polyelectrolyte multilayer (PEM) was used as a solid substrate for three-dimensional antigen-antibody reactions. A dual electrophoresis process was used to induce directional migration and local condensation of antigens and antibodies at the solid substrate, avoiding the long diffusion times associated with antigen-antibody reactions in conventional ELISAs. The electrophoretic forces drove two steps in the ELISA process, namely the adsorption of antigen, and secondary antibody-labelled polystyrene nanoparticles (NP-Ab). The total time needed for dual electrophoresis-driven detection was just 4 min, nearly 2 h faster than a conventional ELISA system. Moreover, the rapid NP-Ab electrophoresis system simultaneously achieved amplification of the specific signal and a reduction in noise, leading to a more sensitive NP-Ab immunoassay with a limit of detection (LOD) of 130 fM, and wide range of detectable concentrations from 0.13 to 130 pM. These results suggest that the combination of dual electrophoresis detection and NP-Ab signal amplification has great potential for future immunoassay systems. PMID:28198385

  10. Acetate fuels the cancer engine.

    PubMed

    Lyssiotis, Costas A; Cantley, Lewis C

    2014-12-18

    Cancer cells have distinctive nutrient demands to fuel growth and proliferation, including the disproportionate use of glucose, glutamine, and fatty acids. Comerford et al. and Mashimo et al. now demonstrate that several types of cancer are avid consumers of acetate, which facilitates macromolecular biosynthesis and histone modification.

  11. Capillary electrophoresis electrospray ionization mass spectrometry interface

    DOEpatents

    Smith, Richard D.; Severs, Joanne C.

    1999-01-01

    The present invention is an interface between a capillary electrophoresis separation capillary end and an electrospray ionization mass spectrometry emitter capillary end, for transporting an anolyte sample from a capillary electrophoresis separation capillary to a electrospray ionization mass spectrometry emitter capillary. The interface of the present invention has: (a) a charge transfer fitting enclosing both of the capillary electrophoresis capillary end and the electrospray ionization mass spectrometry emitter capillary end; (b) a reservoir containing an electrolyte surrounding the charge transfer fitting; and (c) an electrode immersed into the electrolyte, the electrode closing a capillary electrophoresis circuit and providing charge transfer across the charge transfer fitting while avoiding substantial bulk fluid transfer across the charge transfer fitting. Advantages of the present invention have been demonstrated as effective in providing high sensitivity and efficient analyses.

  12. [Disc electrophoresis of collagen protein (author's transl)].

    PubMed

    Reitmayr, P; Verzár, F

    1975-01-01

    The composition of proteins extracted from tendon collagen is investigated by disc electrophoresis. No qualitative differences can be demonstrated between young and old collagen. The action of formaldehyde and methionine on the tendons has no effect on the electrophoretic picture.

  13. Free-Flow Open-Chamber Electrophoresis

    NASA Technical Reports Server (NTRS)

    Sharnez, Rizwan; Sammons, David W.

    1994-01-01

    Free-flow open-chamber electrophoresis variant of free-flow electrophoresis performed in chamber with open ends and in which velocity of electro-osmotic flow adjusted equal to and opposite mean electrophoretic velocity of sample. Particles having electrophoretic mobilities greater than mean mobility of sample particles move toward cathode, those with mobilities less move toward anode. Technique applied to separation of components of mixtures of biologically important substances. Sensitivity enhanced by use of tapered chamber.

  14. Affinity Electrophoresis Using Ligands Attached To Polymers

    NASA Technical Reports Server (NTRS)

    Van Alstine, James M.; Snyder, Robert S.; Harris, J. M.; Brooks, D. E.

    1990-01-01

    In new technique, reduction of electrophoretic mobilities by addition of polyethylene glycol to ligands increases electrophoretic separabilities. In immuno-affinity electrophoresis, modification of ligands extends specificity of electrophoretic separation to particles having surface electric-charge structures otherwise making them electrophoretically inseparable. Modification of antibodies by polyethylene glycol greatly reduces ability to aggregate while enhancing ability to affect electrophoretic mobilities of cells. In hydrophobic-affinity electrophoresis, addition of polyethylene glycol reduces tendency toward aggregation of cells or macromolecules.

  15. Origins of blood acetate in the rat.

    PubMed Central

    Buckley, B M; Williamson, D H

    1977-01-01

    A novel enzymimc cycling assay for the determination of acetate in biological material is described. Measurements of the acetate concentration in blood and liver samples from rats of various ages and nutritional states with this assay are reported. The contribution of the intestine, the liver and the rest of the body to maintaining the concentration of acetate in the circulation is examined. Evidence is presented that the gut flora constitute the main source of acetate in blood of fed adult rats, though endogenous production of acetate is of significance in other situations. The streptozotocin-diabetic rat has an elevated blood acetate concentration. PMID:597244

  16. Microfluidic flow counterbalanced capillary electrophoresis.

    PubMed

    Xia, Ling; Dutta, Debashis

    2013-04-07

    Flow counterbalanced capillary electrophoresis (FCCE) offers a powerful approach to realizing difficult charge based separations in compact microchip devices with application of relatively small electrical voltages. The need for dynamically controlling the pressure-gradient in the FCCE column however presents a significant challenge in implementing this technique on the microchip platform. In this article, we report the use of a simple on-chip pumping unit that allows precise introduction of a periodic pressure-driven backflow into a microfluidic separation channel enabling an FCCE analysis. The backflow in our device was produced by fabricating a shallow segment (0.5 μm deep) downstream of the analysis column (5 μm deep) and applying an electric field across it. A mismatch in the electroosmotic transport rate at the interface of this segment was shown to yield a pressure-gradient that could reverse the flow of the analyte bands without inverting the direction of the electric field. Although such a pressure-gradient also led to additional band broadening in the system, overall, the separation resolution of our device was observed to improve with an increasing number of back-and-forth sample passes through the analysis channel. For our current design, the corresponding improvement in the effective separation length was as much as 52% of the actual distance travelled by the chosen FITC-labeled amino acid samples. The reported device is well suited for further miniaturization of the FCCE method to the nanofluidic length scale which likely would improve its performance, and is easily integrable to other analytical procedures on the microchip platform for lab-on-a-chip applications.

  17. Preparation of Electrically Conductive Polymeric Membranes

    NASA Astrophysics Data System (ADS)

    Encinas, J. C.; Castillo-Ortega, M. M.; Rodríguez, F.; Castaño, V. M.

    2015-10-01

    Cellulose acetate porous membranes, coated with polyaniline, were chemically modified with polyelectrolytes to produce films of varying and controlled porosity and electrical conductivity. The highest electrical conductivity was obtained in membranes prepared with poly(styrene sulfonate) with large pore sizes. The electrical properties as well as scanning electron microscopy (SEM) images are discussed.

  18. Fragrance material review on α-methylbenzyl acetate.

    PubMed

    McGinty, D; Letizia, C S; Api, A M

    2012-09-01

    A toxicologic and dermatologic review of α-methylbenzyl acetate when used as a fragrance ingredient is presented. α-Methylbenzyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for α-methylbenzyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, and repeated dose data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances.

  19. Carbon-isotopic analysis of dissolved acetate

    NASA Technical Reports Server (NTRS)

    Gelwicks, J. T.; Hayes, J. M.

    1990-01-01

    Heating of dried, acetate-containing solids together with oxalic acid dihydrate conveniently releases acetic acid for purification by gas chromatography. For determination of the carbon-isotopic composition of total acetate, the acetate-containing zone of the chromatographic effluent can be routed directly to a combustion furnace coupled to a vacuum system allowing recovery, purification, and packaging of CO2 for mass-spectrometric analysis. For analysis of methyl carbon, acetic acid can be cryogenically trapped from the chromatographic effluent, then transferred to a tube containing excess NaOH. The tube is evacuated, sealed, and heated to 500 degrees C to produce methane by pyrolysis of sodium acetate. Subsequent combustion of the methane allows determination of the 13C content at the methyl position in the parent acetate. With typical blanks, the standard deviation of single analyses is less than 0.4% for acetate samples larger than 5 micromoles. A full treatment of uncertainties is outlined.

  20. Ozone decomposition in aqueous acetate solutions

    SciTech Connect

    Sehested, K.; Holcman, J.; Bjergbakke, E.; Hart, E.J.

    1987-01-01

    The acetate radical ion reacts with ozone with a rate constant of k = (1.5 +/- 0.5) x 10Z dmT mol s . The products from this reaction are CO2, HCHO, and O2 . By subsequent reaction of the peroxy radical with ozone the acetate radical ion is regenerated through the OH radical. A chain decomposition of ozone takes place. It terminates when the acetate radical ion reacts with oxygen forming the unreactive peroxy acetate radical. The chain is rather short as oxygen is developed, as a result of the ozone consumption. The inhibiting effect of acetate on the ozone decay is rationalized by OH scavenging by acetate and successive reaction of the acetate radical ion with oxygen. Some products from the bimolecular disappearance of the peroxy acetate radicals, however, react further with ozone, reducing the effectiveness of the stabilization.

  1. Carbon-isotopic analysis of dissolved acetate.

    PubMed

    Gelwicks, J T; Hayes, J M

    1990-01-01

    Heating of dried, acetate-containing solids together with oxalic acid dihydrate conveniently releases acetic acid for purification by gas chromatography. For determination of the carbon-isotopic composition of total acetate, the acetate-containing zone of the chromatographic effluent can be routed directly to a combustion furnace coupled to a vacuum system allowing recovery, purification, and packaging of CO2 for mass-spectrometric analysis. For analysis of methyl carbon, acetic acid can be cryogenically trapped from the chromatographic effluent, then transferred to a tube containing excess NaOH. The tube is evacuated, sealed, and heated to 500 degrees C to produce methane by pyrolysis of sodium acetate. Subsequent combustion of the methane allows determination of the 13C content at the methyl position in the parent acetate. With typical blanks, the standard deviation of single analyses is less than 0.4% for acetate samples larger than 5 micromoles. A full treatment of uncertainties is outlined.

  2. Quantification of Fumaria officinalis isoquinoline alkaloids by nonaqueous capillary electrophoresis-electrospray ion trap mass spectrometry.

    PubMed

    Sturm, Sonja; Strasser, Eva-Maria; Stuppner, Hermann

    2006-04-21

    A capillary electrophoresis (CE) method using non-aqueous (NA) separation solutions combined with an ion trap mass spectrometer (MS and MS/MS) as detection device is presented for the separation, identification and quantification of isoquinoline alkaloids from Fumaria officinalis. The best results were obtained with a mixture of acetonitrile-methanol (9:1, v/v) containing 60mM ammonium acetate and 2.2M acetic acid as running electrolyte and an applied voltage of 30 kV. Electrospray MS measurements were performed in the positive ionization mode with isopropanol-water (1:1, v/v) as sheath liquid at a flow rate of 3 microl/min. Alkaloids were detected as [M+H](+)-ions and showed typical fragmentation patterns in MS/MS experiments. The developed assay was used for the quantification of seven isoquinoline alkaloids representing different structural subtypes in Fumariae herba extracts and F. herba containing phytopharmaceuticals.

  3. Vibrational spectroscopy and electrophoresis as a "golden means" in monitoring of polysaccharides in medical plant and gels

    NASA Astrophysics Data System (ADS)

    Pielesz, A.

    In recent years, some bioactive polysaccharides isolated from natural sources have attracted much attention in the field of biochemistry and pharmacology. Of them, polysaccharides or their glycoconjugates were shown to exhibit multiple biological activities including anticarcinogenic, anticoagulant, immunostimulating, antioxidant, etc. Pharmacotherapy using plant-derived substances can be currently regarded as a very promising future alternative to conventional therapy. The advanced biotechnologies available today enable chemical investigation of well-defined bioactive plant components as sources of novel drugs. The need for safer drugs without side effects has led to the use of natural ingredients with proven safety. Special interest is focused on plant polysaccharides. This article attempts to review the current structural and conformational characterization of some importantly bioactive monosaccharides isolated from following plant cell-wall: Symphytum officinale (comfrey), Thymus pulegioides (thyme), Trigonella foenum-graecum L. (fenugreek), Tussilago farfara L. (coltsfoot), Hyssopus officinalis (hyssop), Althaea officinalis L. (marshmallow) and Equisetum arvense L. (horsetail). The chemical structures of monosaccharides were analysed using FTIR and Raman spectroscopies as well as cellulose acetate membrane electrophoresis (CAE). The dried plant samples were gently hydrolysed with sulphuric acid. The presence of glucuronic acid, galacturonic acid, alginic acid, glucose, mannose and xylose in the hydrolysates of reference substances and non-defatted plant films was proved. The possibility of a taxonomic classification of plant cell walls based on infrared and Raman spectroscopies and the use of spectral fingerprinting for authentication and detection of adulteration of products rich in cell-wall materials are discussed. Individual bands were selected to monitor the sugar content in medical plant cell walls and to confirm the identity of the analysed plants.

  4. Vibrational spectroscopy and electrophoresis as a "golden means" in monitoring of polysaccharides in medical plant and gels.

    PubMed

    Pielesz, A

    2012-07-01

    In recent years, some bioactive polysaccharides isolated from natural sources have attracted much attention in the field of biochemistry and pharmacology. Of them, polysaccharides or their glycoconjugates were shown to exhibit multiple biological activities including anticarcinogenic, anticoagulant, immunostimulating, antioxidant, etc. Pharmacotherapy using plant-derived substances can be currently regarded as a very promising future alternative to conventional therapy. The advanced biotechnologies available today enable chemical investigation of well-defined bioactive plant components as sources of novel drugs. The need for safer drugs without side effects has led to the use of natural ingredients with proven safety. Special interest is focused on plant polysaccharides. This article attempts to review the current structural and conformational characterization of some importantly bioactive monosaccharides isolated from following plant cell-wall: Symphytum officinale (comfrey), Thymus pulegioides (thyme), Trigonella foenum-graecum L. (fenugreek), Tussilago farfara L. (coltsfoot), Hyssopus officinalis (hyssop), Althaea officinalis L. (marshmallow) and Equisetum arvense L. (horsetail). The chemical structures of monosaccharides were analysed using FTIR and Raman spectroscopies as well as cellulose acetate membrane electrophoresis (CAE). The dried plant samples were gently hydrolysed with sulphuric acid. The presence of glucuronic acid, galacturonic acid, alginic acid, glucose, mannose and xylose in the hydrolysates of reference substances and non-defatted plant films was proved. The possibility of a taxonomic classification of plant cell walls based on infrared and Raman spectroscopies and the use of spectral fingerprinting for authentication and detection of adulteration of products rich in cell-wall materials are discussed. Individual bands were selected to monitor the sugar content in medical plant cell walls and to confirm the identity of the analysed plants.

  5. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium acetate. 184.1721 Section 184.1721 Food and....1721 Sodium acetate. (a) Sodium acetate (C2H3O2Na, CAS Reg. No. 127-09-3 or C2H3O2Na·3H2O, CAS Reg. No. 6131-90-4) is the sodium salt of acetic acid and occurs naturally in plant and animal tissues....

  6. [Advances in functional genomics studies underlying acetic acid tolerance of Saccharomyces cerevisiae].

    PubMed

    Zhao, Xinqing; Zhang, Mingming; Xu, Guihong; Xu, Jianren; Bai, Fengwu

    2014-03-01

    Industrial microorganisms are subject to various stress conditions, including products and substrates inhibitions. Therefore, improvement of stress tolerance is of great importance for industrial microbial production. Acetic acid is one of the major inhibitors in the cellulosic hydrolysates, which affects seriously on cell growth and metabolism of Saccharomyces cerevisiae. Studies on the molecular mechanisms underlying adaptive response and tolerance of acetic acid of S. cerevisiae benefit breeding of robust strains of industrial yeast for more efficient production. In recent years, more insights into the molecular mechanisms underlying acetic acid tolerance have been revealed through analysis of global gene expression and metabolomics analysis, as well as phenomics analysis by single gene deletion libraries. Novel genes related to response to acetic acid and improvement of acetic acid tolerance have been identified, and novel strains with improved acetic acid tolerance were constructed by modifying key genes. Metal ions including potassium and zinc play important roles in acetic acid tolerance in S. cerevisiae, and the effect of zinc was first discovered in our previous studies on flocculating yeast. Genes involved in cell wall remodeling, membrane transport, energy metabolism, amino acid biosynthesis and transport, as well as global transcription regulation were discussed. Exploration and modification of the molecular mechanisms of yeast acetic acid tolerance will be done further on levels such as post-translational modifications and synthetic biology and engineering; and the knowledge obtained will pave the way for breeding robust strains for more efficient bioconversion of cellulosic materials to produce biofuels and bio-based chemicals.

  7. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium acetate. 582.1721 Section 582.1721 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is...

  8. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium acetate. 582.1721 Section 582.1721 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is...

  9. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium acetate. 582.1721 Section 582.1721 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is...

  10. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium acetate. 582.1721 Section 582.1721 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is...

  11. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium acetate. 582.1721 Section 582.1721 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is...

  12. 21 CFR 582.1005 - Acetic acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1005 Acetic acid. (a) Product. Acetic acid. (b) Conditions of use. This substance is...

  13. 21 CFR 582.1005 - Acetic acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1005 Acetic acid. (a) Product. Acetic acid. (b) Conditions of use. This substance is...

  14. 21 CFR 184.1005 - Acetic acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Acetic acid. 184.1005 Section 184.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD....1005 Acetic acid. (a) Acetic acid (C2H4O2, CAS Reg. No. 64-19-7) is known as ethanoic acid. It...

  15. 21 CFR 582.1005 - Acetic acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1005 Acetic acid. (a) Product. Acetic acid. (b) Conditions of use. This substance is...

  16. 21 CFR 582.1005 - Acetic acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1005 Acetic acid. (a) Product. Acetic acid. (b) Conditions of use. This substance is...

  17. 21 CFR 582.1005 - Acetic acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1005 Acetic acid. (a) Product. Acetic acid. (b) Conditions of use. This substance is...

  18. 21 CFR 522.2476 - Trenbolone acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... days. (A) 140 milligrams (mg) trenbolone acetate (one implant consisting of 7 pellets, each pellet containing 20 mg trenbolone acetate) per implant dose. (B) 140 mg trenbolone acetate (one implant consisting... 29 mg tylosin tartrate) per implant dose. (ii) Indications for use. For improved feed...

  19. 21 CFR 522.2476 - Trenbolone acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... days. (A) 140 milligrams (mg) trenbolone acetate (one implant consisting of 7 pellets, each pellet containing 20 mg trenbolone acetate) per implant dose. (B) 140 mg trenbolone acetate (one implant consisting... 29 mg tylosin tartrate) per implant dose. (ii) Indications for use. For improved feed...

  20. Photochemistry of 2-nitrobenzylidene acetals.

    PubMed

    Sebej, Peter; Solomek, Tomás; Hroudná, L'ubica; Brancová, Pavla; Klán, Petr

    2009-11-20

    Photolysis of dihydroxy compounds (diols) protected as 2-nitrobenzylidene acetals (ONBA) and subsequent acid- or base-catalyzed hydrolysis of the 2-nitrosobenzoic acid ester intermediates result in an efficient and high-yielding release of the substrates. We investigated the scope and limitations of ONBA photochemistry and expanded upon earlier described two-step procedures to show that the protected diols of many structural varieties can also be liberated in a one-pot procedure. In view of the fact that the acetals of nonsymmetrically substituted diols are converted into one of the corresponding 2-nitrosobenzoic acid ester isomers with moderate to high regioselectivity, the mechanism of their formation was studied using various experimental techniques. The experimental data were found to be in agreement with DFT-based quantum chemical calculations that showed the preferential cleavage occurs on the acetal C-O bond in the vicinity of more electron-withdrawing (or less electron-donating) groups. The study also revealed considerable complexity in the cleavage mechanism and that the structural variations in the substrate can significantly alter the reaction pathway. This deprotection strategy was found to be also applicable for 2-thioethanol when released from the corresponding monothioacetal in the presence of a reducing agent, such as ascorbic acid.

  1. Preirradiation grafting of ethylene vinyl acetate copolymer resins

    NASA Astrophysics Data System (ADS)

    Ringrose, B. J.; Kronfli, E.

    1999-07-01

    Acrylic acid was graft copolymerised on to EVA powdered resins containing 9%, 18% and 28% vinyl acetate. A preirradiation grafting method was used and the effect on graft level of varying the parameters of gamma irradiation dose (2-50 kGy), dose rate (0.5-5 kGy h -1), monomer concentration (2.5-25%) and grafting time (1-4 h) and temperature (35-98°C) was investigated. The graft copolymer resins were converted into film and characterised in terms of their hydrophilicity and electrolytic resistance in alkaline solutions. Depending on the vinyl acetate content and rheological properties of the base EVA copolymer, high graft weight resins can be converted into semipermeable films suitable for a range of applications including battery separator membranes and topical medical dressings.

  2. All natural cellulose acetate-Lemongrass essential oil antimicrobial nanocapsules.

    PubMed

    Liakos, Ioannis L; D'autilia, Francesca; Garzoni, Alice; Bonferoni, Cristina; Scarpellini, Alice; Brunetti, Virgilio; Carzino, Riccardo; Bianchini, Paolo; Pompa, Pier Paolo; Athanassiou, Athanassia

    2016-08-30

    Nanocapsules and nanoparticles play an essential role in the delivery of pharmaceutical agents in modern era, since they can be delivered in specific tissues and cells. Natural polymers, such as cellulose acetate, are becoming very important due to their availability, biocompatibility, absence of toxicity and biodegradability. In parallel, essential oils are having continuous growth in biomedical applications due to the inherent active compounds that they contain. A characteristic example is lemongrass oil that has exceptional antimicrobial properties. In this work, nanocapsules of cellulose acetate with lemongrass oil were developed with the solvent/anti-solvent method with resulting diameter tailored between 95 and 185nm. Various physico-chemical and surface analysis techniques were employed to investigate the formation of the nanocapsules. These all-natural nanocapsules found to well bioadhere to mucous membranes and to have very good antimicrobial properties at little concentrations against Escherichia coli and Staphylococcus aureus.

  3. Bioenergetic models for acetate and phosphate transport in bacteria important in enhanced biological phosphorus removal.

    PubMed

    Burow, Luke C; Mabbett, Amanda N; McEwan, Alastair G; Bond, Philip L; Blackall, Linda L

    2008-01-01

    Most of our understanding of the physiology of microorganisms is the result of investigations in pure culture. However, in order to understand complex environmental processes, there is a need to investigate mixed microbial communities. This is true for enhanced biological phosphorus removal (EBPR), an environmental process that results in the enrichment of the polyphosphate-accumulating organism Accumulibacter spp. and the glycogen non-polyphosphate accumulating organism Defluviicoccus spp. We investigated acetate and inorganic phosphate (P(i)) uptake in enrichments of Accumulibacter spp. and acetate uptake in enrichments of Defluviicoccus spp. For both enrichments, anaerobic acetate uptake assays in the presence of the protonophore, carbonyl cyanide m-chlorophenylhydrazone (CCCP) or the membrane potential (Delta psi) uncoupler valinomycin, indicated that acetate is likely to be taken up by a permease-mediated process driven by the Delta psi. Further investigation with the sodium ionophore monensin suggested that anaerobic acetate uptake by Defluviicoccus spp. may in part be dependent on a sodium potential. Results of this study also suggest that Accumulibacter spp. generate a proton motive force (pmf or Delta p) for anaerobic acetate uptake by efflux of protons in symport with P(i) through an inorganic phosphate transport (Pit) system. In contrast, we suggest that the anaerobic Delta p in Defluviicoccus spp. is generated by an efflux of protons across the cell membrane by the fumarate respiratory system, or by extrusion of sodium ions via decarboxylation of methylmalonyl-CoA. Aerobic P(i) uptake by the Accumulibacter spp. enrichment was strongly inhibited in the presence of an ATPase inhibitor, suggesting that the phosphate-specific transport (Pst) system is important even under relatively high concentrations of P(i). Acetate permease activity in these microorganisms may play an important role in the competition for acetate in the often acetate-limited EBPR

  4. Effect of membrane polymeric materials on relationship between surface pore size and membrane fouling in membrane bioreactors

    NASA Astrophysics Data System (ADS)

    Miyoshi, Taro; Yuasa, Kotaku; Ishigami, Toru; Rajabzadeh, Saeid; Kamio, Eiji; Ohmukai, Yoshikage; Saeki, Daisuke; Ni, Jinren; Matsuyama, Hideto

    2015-03-01

    We investigated the effect of different membrane polymeric materials on the relationship between membrane pore size and development of membrane fouling in a membrane bioreactor (MBR). Membranes with different pore sizes were prepared using three different polymeric materials, cellulose acetate butyrate (CAB), polyvinyl butyral (PVB), and polyvinylidene fluoride (PVDF), and the development of membrane fouling in each membrane was evaluated by batch filtration tests using a mixed liquor suspension obtained from a laboratory-scale MBR. The results revealed that the optimal membrane pore size to mitigate membrane fouling differed depending on membrane polymeric material. For PVDF membranes, the degree of membrane fouling decreased as membrane pore size increased. In contrast, CAB membranes with smaller pores had less fouling propensity than those with larger ones. Such difference can be attributed to the difference in major membrane foulants in each membrane; in PVDF, they were small colloids or dissolved organics in which proteins are abundant, and in CAB, microbial flocs. The results obtained in this study strongly suggested that optimum operating conditions of MBRs differ depending on the characteristics of the used membrane.

  5. Synthesis of cellulose acetate and carboxymethylcellulose from sugarcane straw.

    PubMed

    Candido, R G; Gonçalves, A R

    2016-11-05

    Sugarcane straw (SCS) is a raw material with high potential for production of cellulose derivatives due to its morphology and structure. The proposal of this work was to synthesize cellulose acetate (CA) and carboxymethylcellulose (CMC) from sugarcane straw cellulose, and applied the CA in the preparation of a membrane. The cellulose extraction was carried out in four steps. Firstly, SCS was treated with H2SO4 (10% v/v) followed by NaOH (5% w/v) treatment. Subsequently, a chelating process was performed before ending the extraction process with chemical bleaching using H2O2 (5% v/v). The extracted cellulose was employed in the obtainment of CA and CMC. The CA presented a degree of substitution (DS) of 2.72. Its FTIR spectrum showed that practically all hydroxyl groups were replaced by acetate groups. The membrane synthesized from CA was dense and homogeneous. The presence of small particles on the top and bottom surfaces decreased the mechanical resistance of the membrane. The CMC presented a low DS (0.4) demonstrating the carboxymethylation reaction was not very effective due to the presence of lignin. These results proved that SCS can be utilized in the synthesis of CA and CMC.

  6. Perselectivity of porous cellulose nitrate membranes in evapomeation with temperature difference

    SciTech Connect

    Uragami, T.; Komatsu, R.; Miyata, T.

    1995-12-01

    Ethanol-permselectivity from aqueous ethanol solutions through porous cellulose nitrate membranes was investigated by evaporation with temperature difference under various conditions. On the other hand, same experiments using porous cellulose acetate were carried out. From these results of porous cellulose nitrate and cellulose acetate membranes, mechanism of permeation and separation for ethanol-permselectivity through cellulose nitrate membranes is discussed from viewpoints of physical and chemical structures of porous cellulose ester membranes.

  7. A new injection method for soil nutrient analysis in capillary electrophoresis

    NASA Astrophysics Data System (ADS)

    Smolka, M.; Puchberger-Enengl, D.; Bipoun, M.; Fercher, G.; Klasa, A.; Krutzler, C.; Keplinger, F.; Vellekoop, M. J.

    2013-05-01

    We present a new method for the direct injection of liquid sample into a capillary electrophoresis (CE) device. Instead of a double-T injection mechanism, a single inlet provided with a membrane filter is used. From a reservoir on top of this inlet, the liquid directly enters the separation channel through the membrane. The driving force is a short electrical pulse. This avoids an additional sample channel, so that the chip needs only three microfluidic connects and no mechanical sample pumping is demanded. The high injection reproducibility and the comparatively simple setup open up the way for mobile application of soil analysis.

  8. Free flow cell electrophoresis using zwitterionic buffer

    NASA Technical Reports Server (NTRS)

    Rodkey, R. Scott

    1990-01-01

    Studies of a zwitterionic buffer formulated for cell electrophoresis were done using the McDonnell-Douglas Continuous Flow Electrophoresis System. Standard buffers were analyzed for their stability in the electrical field and the results showed that both buffers tested were inherently unstable. Further, titration studies showed that the standards buffers buffered poorly at the pH employed for electrophoresis. The zwitterionic buffer buffered well at its nominal pH and was shown to be stable in the electrical field. Comparative studies of the buffer with standard cell separation buffers using formalin fixed rabbit and goose red blood cells showed that the zwitterionic buffer gave better resolution of the fixed cells. Studies with viable hybridoma cells showed that buffer Q supported cell viability equal to Hank's Balanced Salt Solution and that hybridoma cells in different stages of the growth cycle demonstrated reproducible differences in electrophoretic mobility.

  9. Aggregates of human erythrocyte membrane sialoglycoproteins in the presence of deoxycholate and dodecyl sulfate.

    PubMed

    Liljas, L

    1978-02-15

    Gel electrophoresis in the presence of deoxycholate of human erythrocyte membranes solubilized with deoxycholate resolves four glycoprotein zones. Electrophoresis in dodecyl sulfate in a second dimension reveals several components, three of which migrate in the region of PAS-2. One of the zones in deoxycholate gel electrophoresis contains component PAS-3, and this glycoprotein seems to exist as a monomer in deoxycholate, but aggregates partially upon addition of dodecyl sulfate. The major sialoglycoprotein migrates as a diffuse zone in dodecyl sulfate. The major sialoglycoprotein migrates as a diffuse zone in deoxycholate gel electrophoresis, indicating association and dissociation during the electrophoresis. The use of deoxycholate followed by dodecyl sulfate in two-dimentional electrophoresis gave high resolution of membrane proteins and can be used for detection of complexes in one of the detergents.

  10. Electromembrane extraction: distribution or electrophoresis?

    PubMed

    Seip, Knut Fredrik; Jensen, Henrik; Sønsteby, Marit Hovde; Gjelstad, Astrid; Pedersen-Bjergaard, Stig

    2013-03-01

    This paper presents for the first time a phenomenological theoretical model for the time dependent distribution of analytes during electromembrane extraction (EME). The model was verified experimentally for a range of model drugs and peptides. Analytes were extracted from an acidified aqueous sample solution, through an organic supported liquid membrane (SLM), and into an acidified aqueous acceptor solution. Mass transfer was governed by an applied electric field across the SLM. A rapid depletion was seen in the sample during extractions, with a steady increase in the amount accumulated in the acceptor solution. This was in good accordance with the theoretical model. A deviation from the modeled behavior was seen for some of the peptides where trapping of analyte in the SLM was high. The results demonstrated for the first time that EME behaved like a distribution system, with voltage dependent distribution coefficients. In addition, electrokinetic migration was observed across the SLM, which added an electrophoretic component to the mass transfer. This improved theoretical understanding will be highly beneficial for future optimization and development of applications using EME.

  11. Application of Microchip Electrophoresis for Clinical Tests

    NASA Astrophysics Data System (ADS)

    Yatsushiro, Shouki; Kataoka, Masatoshi

    Microchip electrophoresis has recently attracted much attention in the field of nuclear acid analysis due to its high efficiency, ease of operation, low consumption of samples and reagents, and relatively low costs. In addition, the analysis has expanded to an analytical field like not only the analysis of DNA but also the analysis of RNA, the protein, the sugar chain, and the cellular function, etc. In this report, we showed that high-performance monitoring systems for human blood glucose levels and α-amylase activity in human plasma using microchip electrophoresis.

  12. Undergraduate physics laboratory: Electrophoresis in chromatography paper

    NASA Astrophysics Data System (ADS)

    Hyde, Alexander; Batishchev, Oleg

    2015-12-01

    An experiment studying the physical principles of electrophoresis in liquids was developed for an undergraduate laboratory. We have improved upon the standard agarose gel electrophoresis experimental regime with a straightforward and cost-effective procedure, in which drops of widely available black food coloring were separated by electric field into their dye components on strips of chromatography paper soaked in a baking soda/water solution. Terminal velocities of seven student-safe dyes were measured as a function of the electric potential applied along the strips. The molecular mobility was introduced and calculated by analyzing data for a single dye. Sources of systematic and random errors were investigated.

  13. Simultaneous determination of antidepressants by non-aqueous or quasi-non-aqueous capillary electrophoresis.

    PubMed

    Sasajima, Yasuhide; Lim, Lee Wah; Takeuchi, Toyohide; Suenami, Koichi; Sato, Kiyohito; Takekoshi, Yuji

    2010-01-01

    Simultaneous determinations of 20 antidepressants were carried out by non-aqueous capillary electrophoresis using a background electrolyte consisting of an organic solvent. A bubble cell fused silica capillary (112.5 cm x 50 microm i.d., 150 microm i.d. bubble) was used as an electrophoresis tube. The determination was carried out at 215 nm, while the detection wavelength between 190 and 500 nm was selected for qualitative analysis. When an acetonitrile solution alone was used as the background electrolyte, good separation was observed, but it was not sufficient to separate all tested analytes. It was found that better separation was acquired by adding a few other solvents into acetonitrile, such as water and methanol; the best separation was achieved with a mixture of acetonitrile containing 60 mM ammonium acetate and 1 M acetic acid/water/methanol (100:1:0.5, v/v/v). As for the plasma sample, liquid-liquid extraction and solid-phase extraction (SPE) were considered; as a result, SPE with Oasis HLB was found to be most suitable. The present method is very useful as regards to plasma samples.

  14. Expression of platelet membrane glycoproteins and alpha-granule proteins by a human erythroleukemia cell line (HEL).

    PubMed Central

    Tabilio, A; Rosa, J P; Testa, U; Kieffer, N; Nurden, A T; Del Canizo, M C; Breton-Gorius, J; Vainchenker, W

    1984-01-01

    We demonstrate that HEL, a human erythroleukemic cell line, has numerous megakaryocytic markers which were markedly enhanced following the addition of the inducers dimethyl sulfoxide or 12-O-tetradecanoylphorbol-13-acetate to the culture medium. Ultrastructural and cytochemical studies showed: (i) the presence of organelles morphologically resembling the platelet alpha-granules; and (ii) a peroxidase activity with the same characteristics as that specifically found in platelets. The platelet alpha-granule proteins (von Willebrand factor, platelet factor-4 and beta-thromboglobulin) were immunologically detected in the HEL cell cytoplasm and their amounts increased after induction. Of particular interest was the presence of platelet membrane proteins. A monoclonal antibody specific for glycoprotein Ib bound to HEL cells. Platelet membrane glycoproteins IIb and IIIa were identified on intact cells using specific antibodies in a binding assay or in cell lysates using either crossed immunoelectrophoresis or an immunoblotting procedure following SDS-polyacrylamide gel electrophoresis. Most HEL cells also expressed the platelet alloantigen PIA1. All of the platelet membrane proteins were present in higher amounts after induction. Glycophorin A, specific for the erythroid lineage, was also detected on HEL cells. Thus, while confirming the presence of erythroid markers, our studies provide evidence that the HEL cell line also expresses platelet antigens. As such, HEL cells represent a unique system with which to study the biosynthesis of platelet-specific proteins and glycoproteins. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. PMID:6201359

  15. [Advances in the progress of anti-bacterial biofilms properties of acetic acid].

    PubMed

    Gao, Xinxin; Jin, Zhenghua; Chen, Xinxin; Yu, Jia'ao

    2016-06-01

    Bacterial biofilms are considered to be the hindrance in the treatment of chronic wound, because of their tolerance toward antibiotics and other antimicrobial agents. They also have strong ability to escape from the host immune attack. Acetic acid, as a kind of organic weak acid, can disturb the biofilms by freely diffusing through the bacterial biofilms and bacterial cell membrane structure. Then the acid dissociates to release the hydrogen ions, leading to the disorder of the acid-base imbalance, change of protein conformation, and the degradation of the DNA within the membranes. This paper reviews the literature on the characteristics and treatment strategies of the bacterial biofilms and the acetic acid intervention on them, so as to demonstrate the roles acetic acid may play in the treatment of chronic wound, and thus provide a convincing treatment strategy for this kind of disease.

  16. Utilization of acetate by Beggiatoa.

    PubMed

    Burton, S D; Morita, R Y; Miller, W

    1966-03-01

    Burton, Sheril D. (Institute of Marine Science, University of Alaska, College), Richard Y. Morita, and Wayne Miller. Utilization of acetate by Beggiatoa. J. Bacteriol. 91:1192-1200. 1966.-A proposed system which would permit acetate incorporation into four-carbon compounds without the presence of key enzymes of the citric acid cycle or glyoxylate cycle is described. In this system, acetyl-coenzyme A (CoA) is condensed with glyoxylate to form malate, which, in turn, is converted to oxaloacetate. Oxaloacetate then reacts with glutamate to produce alpha-ketoglutarate, which is subsequently converted to isocitrate. Cleavage of isocitrate produces glyoxylate and succinate. Thus, the proposed system is similar to the glyoxylate bypass in that malate is produced from glyoxylate and acetyl-CoA, but differs from both the citric acid cycle and the glyoxylate bypass, since citrate and fumarate are not involved. Fumarase, aconitase, catalase, citritase, pyruvate kinase, enolase, phosphoenolpyruvate carboxylase, lactic dehydrogenase, alpha-ketoglutarate dehydrogenase, and condensing enzyme were not detectable in crude extracts of Beggiatoa. Succinate was oxidized by a soluble enzyme not associated with an electron-transport particle. Isocitrate was identified as the sole compound labeled when C(14)O(2) was added to a reduced nicotinamide adenine dinucleotide, CO(2) generating system (crystalline glucose-6-phosphate dehydrogenase and glucose-6-phosphate) in the presence of alpha-ketoglutarate.

  17. Development of nanofibrous cellulose acetate/gelatin skin substitutes for variety wound treatment applications.

    PubMed

    Vatankhah, Elham; Prabhakaran, Molamma P; Jin, Guorui; Mobarakeh, Laleh Ghasemi; Ramakrishna, Seeram

    2014-02-01

    The major component of fibrous extracellular matrix of dermis is composed of a complex combination of proteins and polysaccharides. Electrospun cellulose acetate/gelatin might be an effective simulator of the structure and composition of native skin and during this study, we electrospun cellulose acetate/gelatin membranes in various compositions and their performance as a scaffold for either skin tissue engineering or as a wound dressing was evaluated. Skin treatment products, whether tissue-engineered scaffolds or wound dressings, should be sufficiently hydrophilic to allow for gas and fluid exchange and absorb excess exudates while controlling the fluid loss. However, a wound dressing should be easily removable without causing tissue damage and a tissue-engineered scaffold should be able to adhere to the wound, and support cell proliferation during skin regeneration. We showed that these distinct adherency features are feasible just by changing the composition of cellulose acetate and gelatin in composite cellulose acetate/gelatin scaffolds. High proliferation of human dermal fibroblasts on electrospun cellulose acetate/gelatin 25:75 confirmed the capability of cellulose acetate/gelatin 25:75 nanofibers as a tissue-engineered scaffold, while the electrospun cellulose acetate/gelatin 75:25 can be a potential low-adherent wound dressing.

  18. SDS-Polyacrylamide Gel Electrophoresis of Proteins.

    PubMed

    Sambrook, Joseph; Russell, David W

    2006-09-01

    INTRODUCTIONThis protocol describes the separation of proteins by SDS-polyacrylamide gel electrophoresis. SDS is used with a reducing agent and heat to dissociate the proteins. SDS-polypeptide complexes form and migrate through the gels according to the size of the polypeptide. By using markers of known molecular weight, the molecular weight of the polypeptide chain(s) can be estimated.

  19. A Simple Vertical Slab Gel Electrophoresis Apparatus.

    ERIC Educational Resources Information Center

    Carter, J. B.; And Others

    1983-01-01

    Describes an inexpensive, easily constructed, and safe vertical slab gel kit used routinely for sodium dodecyl sulphate-polyacrylamide gel electrophoresis research and student experiments. Five kits are run from a single transformer. Because toxic solutions are used, students are given plastic gloves and closely supervised during laboratory…

  20. Fractionation of liver proteins by preparative electrophoresis.

    PubMed

    Fountoulakis, M; Juranville, J-F; Tsangaris, G; Suter, L

    2004-02-01

    Proteomics offers unique possibilities to investigate changes in the levels and modifications of proteins involved in the pathomechanisms of diseases and toxic events. However, search for potential drug targets and disease or toxicity markers is limited by the fact that mainly the high-abundance, hydrophilic proteins are visualized in two-dimensional gels. Here we studied the enrichment of rat liver cytosolic proteins by preparative electrophoresis. Preparative electrophoresis was performed with the PrepCell apparatus in the presence of 0.1% lithium dodecyl sulfate. Lithium dodecyl sulfate was exchanged against agents compatible with isoelectric focusing prior to the two-dimensional gel electrophoresis. Proteins were identified from two-dimensional gels by matrix-assisted laser desorption ionization time-of-flight mass specrometry. Low- and middle-size proteins and low-abundance proteins, which had not been found before, were enriched by preparative electrophoresis. The present study represents a contribution of proteomics in the quantification of differences in the levels of low-abundance liver proteins in toxicity studies.

  1. Increasing Sensitivity In Continuous-Flow Electrophoresis

    NASA Technical Reports Server (NTRS)

    Sharnez, Rizwan; Sammons, David W.

    1994-01-01

    Sensitivity of continuous-flow electrophoresis (CFE) chamber increased by introducing lateral gradients in concentration of buffer solution and thickness of chamber. Such gradients, with resulting enhanced separation, achieved in CFE chamber with wedge-shaped cross section and collateral flow. Enables improved separations of homogeneous components of mixtures of variety of biologically important substances.

  2. DNA DAMAGE QUANTITATION BY ALKALINE GEL ELECTROPHORESIS.

    SciTech Connect

    SUTHERLAND,B.M.; BENNETT,P.V.; SUTHERLAND, J.C.

    2004-03-24

    Physical and chemical agents in the environment, those used in clinical applications, or encountered during recreational exposures to sunlight, induce damages in DNA. Understanding the biological impact of these agents requires quantitation of the levels of such damages in laboratory test systems as well as in field or clinical samples. Alkaline gel electrophoresis provides a sensitive (down to {approx} a few lesions/5Mb), rapid method of direct quantitation of a wide variety of DNA damages in nanogram quantities of non-radioactive DNAs from laboratory, field, or clinical specimens, including higher plants and animals. This method stems from velocity sedimentation studies of DNA populations, and from the simple methods of agarose gel electrophoresis. Our laboratories have developed quantitative agarose gel methods, analytical descriptions of DNA migration during electrophoresis on agarose gels (1-6), and electronic imaging for accurate determinations of DNA mass (7-9). Although all these components improve sensitivity and throughput of large numbers of samples (7,8,10), a simple version using only standard molecular biology equipment allows routine analysis of DNA damages at moderate frequencies. We present here a description of the methods, as well as a brief description of the underlying principles, required for a simplified approach to quantitation of DNA damages by alkaline gel electrophoresis.

  3. Role of gravity in preparative electrophoresis

    NASA Technical Reports Server (NTRS)

    Bier, M.

    1975-01-01

    The fundamental formulas of electrophoresis are derived microscopically and applied to the problem of isotachophoresis. A simple physical model of the isotachophoresis front is proposed. The front motion and structure are studied in the simplified case without convection, diffusion and non-electric external forces.

  4. Lipocytes from normal rat liver release a neutral metalloproteinase that degrades basement membrane (type IV) collagen.

    PubMed Central

    Arthur, M J; Friedman, S L; Roll, F J; Bissell, D M

    1989-01-01

    We report a proteinase that degrades basement-membrane (type IV) collagen and is produced by the liver. Its cellular source is lipocytes (fat-storing or Ito cells). Lipocytes were isolated from normal rat liver and established in primary culture. The cells synthesize and secrete a neutral proteinase, which by gelatin-substrate gel electrophoresis and gel filtration chromatography, has a molecular mass of 65,000 D. The enzyme is secreted in latent form and is activated by p-aminophenylmercuric acetate but not by trypsin. Enzyme activity in the presence of EDTA is restored selectively by zinc and is unaffected by serine-protease inhibitors. In assays with radiolabeled soluble substrates, it degrades native type IV (basement membrane) collagen but not interstitial collagen types I or V and exhibits no activity against laminin or casein. At temperatures causing partial denaturation of soluble collagen in vitro, it rapidly degrades types I and V. Thus, it is both a type IV collagenase and gelatinase. The enzyme may play a role in initiating breakdown of the subendothelial matrix in the Disse space as well as augmenting the effects of collagenases that attack native interstitial collagen. Images PMID:2551922

  5. Acetic acid induces pH-independent cellular energy depletion in Salmonella enterica.

    PubMed

    Tan, Sin Mei; Lee, Sui Mae; Dykes, Gary A

    2015-03-01

    Weak organic acids are widely used as preservatives and disinfectants in the food industry. Despite their widespread use, the antimicrobial mode of action of organic acids is still not fully understood. This study investigated the effect of acetic acid on the cell membranes and cellular energy generation of four Salmonella strains. Using a nucleic acid/protein assay, it was established that acetic acid did not cause leakage of intracellular components from the strains. A scanning electron microscopy study further confirmed that membrane disruption was not the antimicrobial mode of action of acetic acid. Some elongated Salmonella cells observed in the micrographs indicated a possibility that acetic acid may inhibit DNA synthesis in the bacterial cells. Using an ATP assay, it was found that at a neutral pH, acetic acid caused cellular energy depletion with an ADP/ATP ratio in the range between 0.48 and 2.63 (p<0.05) that was apparent for the four Salmonella strains. We suggest that this effect was probably due solely to the action of undissociated acid molecules. The antimicrobial effect of acetic acid was better under acidic conditions (ADP/ATP ratio of 5.56 ± 1.27; p<0.05), where the role of both pH and undissociated acid molecules can act together. We concluded that the inhibitory effect of acetic acid is not solely attributable to acidic pH but also to undissociated acid molecules. This finding has implication for the use of acetic acid as an antimicrobial against Salmonella on food products, such as chicken meat, which can buffer its pH.

  6. Study on dicarboxylic acids in aerosol samples with capillary electrophoresis.

    PubMed

    Adler, Heidi; Sirén, Heli

    2014-01-01

    The research was performed to study the simultaneous detection of a homologous series of α , ω -dicarboxylic acids (C2-C10), oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, and sebacic acids, with capillary electrophoresis using indirect UV detection. Good separation efficiency in 2,6-pyridinedicarboxylic acid as background electrolyte modified with myristyl trimethyl ammonium bromide was obtained. The dicarboxylic acids were ionised and separated within five minutes. For the study, authentic samples were collected onto dry cellulose membrane filters of a cascade impactor (12 stages) from outdoor spring aerosols in an urban area. Hot water and ultrasonication extraction methods were used to isolate the acids from membrane filters. Due to the low concentrations of acids in the aerosols, the extracts were concentrated with solid-phase extraction (SPE) before determination. The enrichment of the carboxylic acids was between 86 and 134% with sample pretreatment followed by 100-time increase by preparation of the sample to 50  μ L. Inaccuracy was optimised for all the sample processing steps. The aerosols contained dicarboxylic acids C2-C10. Then, mostly they contained C2, C5, and C10. Only one sample contained succinic acid. In the study, the concentrations of the acids in aerosols were lower than 10 ng/m(3).

  7. Nonlinear gel electrophoresis: an analogy with ideal fluid flow.

    PubMed

    Dennison, C; Phillips, A M; Nevin, J M

    1983-12-01

    The behavior of electrolytes undergoing electrophoresis in various shaped gels was investigated using bromphenol blue as a model electrolyte. The results suggest that during gel electrophoresis, small electrolytes behave in a manner analogous to the flow of ideal, irrotational fluids.

  8. Using Gel Electrophoresis To Illustrate Protein Diversity and Isoelectric Point.

    ERIC Educational Resources Information Center

    Browning, Mark; Vanable, Joseph

    2002-01-01

    Demonstrates the differences in protein structures by focusing on isoelectric point with an experiment that is observable under certain pH levels in gel electrophoresis. Explains the electrophoresis procedure and reports results of the experiments. (YDS)

  9. Enzymatic production of glycerol acetate from glycerol.

    PubMed

    Oh, Seokhyeon; Park, Chulhwan

    2015-02-01

    In this study, we report the enzymatic production of glycerol acetate from glycerol and methyl acetate. Lipases are essential for the catalysis of this reaction. To find the optimum conditions for glycerol acetate production, sequential experiments were designed. Type of lipase, lipase concentration, molar ratio of reactants, reaction temperature and solvents were investigated for the optimum conversion of glycerol to glycerol acetate. As the result of lipase screening, Novozym 435 (Immobilized Candida antarctica lipase B) was turned out to be the optimal lipase for the reaction. Under the optimal conditions (2.5 g/L of Novozym 435, 1:40 molar ratio of glycerol to methyl acetate, 40 °C and tert-butanol as the solvent), glycerol acetate production was achieved in 95.00% conversion.

  10. Membrane stabilizer

    DOEpatents

    Mingenbach, William A.

    1988-01-01

    A device is provided for stabilizing a flexible membrane secured within a frame, wherein a plurality of elongated arms are disposed radially from a central hub which penetrates the membrane, said arms imposing alternately against opposite sides of the membrane, thus warping and tensioning the membrane into a condition of improved stability. The membrane may be an opaque or translucent sheet or other material.

  11. Transcriptome analysis of acetic-acid-treated yeast cells identifies a large set of genes whose overexpression or deletion enhances acetic acid tolerance.

    PubMed

    Lee, Yeji; Nasution, Olviyani; Choi, Eunyong; Choi, In-Geol; Kim, Wankee; Choi, Wonja

    2015-08-01

    Acetic acid inhibits the metabolic activities of Saccharomyces cerevisiae. Therefore, a better understanding of how S. cerevisiae cells acquire the tolerance to acetic acid is of importance to develop robust yeast strains to be used in industry. To do this, we examined the transcriptional changes that occur at 12 h post-exposure to acetic acid, revealing that 56 and 58 genes were upregulated and downregulated, respectively. Functional categorization of them revealed that 22 protein synthesis genes and 14 stress response genes constituted the largest portion of the upregulated and downregulated genes, respectively. To evaluate the association of the regulated genes with acetic acid tolerance, 3 upregulated genes (DBP2, ASC1, and GND1) were selected among 34 non-protein synthesis genes, and 54 viable mutants individually deleted for the downregulated genes were retrieved from the non-essential haploid deletion library. Strains overexpressing ASC1 and GND1 displayed enhanced tolerance to acetic acid, whereas a strain overexpressing DBP2 was sensitive. Fifty of 54 deletion mutants displayed enhanced acetic acid tolerance. Three chosen deletion mutants (hsps82Δ, ato2Δ, and ssa3Δ) were also tolerant to benzoic acid but not propionic and sorbic acids. Moreover, all those five (two overexpressing and three deleted) strains were more efficient in proton efflux and lower in membrane permeability and internal hydrogen peroxide content than controls. Individually or in combination, those physiological changes are likely to contribute at least in part to enhanced acetic acid tolerance. Overall, information of our transcriptional profile was very useful to identify molecular factors associated with acetic acid tolerance.

  12. Two methods that facilitate autoradiography of small /sup 32/P-labeled DNA fragments following electrophoresis in agarose gels

    SciTech Connect

    Cockerill, P.N.

    1988-02-01

    Two methods which permit detection by autoradiography of small /sup 32/P-labeled DNA fragments resolved by agarose gel electrophoresis are described. Agarose gel electrophoresis poses problems for autoradiography as (i) the gels are normally too thick to allow autoradiography without being dried first, and (ii) fragments of DNA of 1000 bp or less in length are readily lost during drying. In this study DNA fragments as small as 121 bp have been retained in agarose gels upon drying. This has been achieved by either (i) first fixing the DNA with the cationic detergent cetyltrimethylammonium bromide, or (ii) drying the agarose gels onto Zeta-Probe charge-modified membranes.

  13. Interactions of hemoglobin in live red blood cells measured by the electrophoresis release test.

    PubMed

    Su, Yan; Gao, Lijun; Ma, Qiang; Zhou, Lishe; Qin, Liangyi; Han, Lihong; Qin, Wenbin

    2010-09-01

    To elucidate the protein-protein interactions of hemoglobin (Hb) variants A and A(2), HbA was first shown to bind with HbA(2) in live red blood cells (RBCs) by diagonal electrophoresis and then the interaction between HbA and HbA(2) outside the RBC was shown by cross electrophoresis. The starch-agarose gel electrophoresis of hemolysate, RBCs, freeze-thawed RBCs and the supernatant of freeze-thawed RBCs showed that the interaction between HbA and HbA(2) was affected by membrane integrity. To identify the proteins involved in the interaction, protein components located between HbA and HbA(2) in RBCs (RBC HbA-HbA(2)) and hemolysate (hemolysate HbA-HbA(2)) were isolated from the starch-agarose gel and separated by 5-12% SDS-PAGE. The results showed that there was a ≈22 kDa protein band located in the RBC HbA-HbA(2) but not in hemolysate HbA-HbA(2). Sequencing by LC/MS/MS showed that this band was a protein complex that included mainly thioredoxin peroxidase B, α-globin, δ-globin and β-globin. Thus, using our unique in vivo whole blood cell electrophoresis release test, Hbs were proven for the first time to interact with other proteins in the live RBC.

  14. 21 CFR 184.1005 - Acetic acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Acetic acid. 184.1005 Section 184.1005 Food and... Substances Affirmed as GRAS § 184.1005 Acetic acid. (a) Acetic acid (C2H4O2, CAS Reg. No. 64-19-7) is known as ethanoic acid. It occurs naturally in plant and animal tissues. It is produced by fermentation...

  15. 21 CFR 184.1005 - Acetic acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Acetic acid. 184.1005 Section 184.1005 Food and... Substances Affirmed as GRAS § 184.1005 Acetic acid. (a) Acetic acid (C2H4O2, CAS Reg. No. 64-19-7) is known as ethanoic acid. It occurs naturally in plant and animal tissues. It is produced by fermentation...

  16. 21 CFR 184.1005 - Acetic acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Acetic acid. 184.1005 Section 184.1005 Food and... Substances Affirmed as GRAS § 184.1005 Acetic acid. (a) Acetic acid (C2H4O2, CAS Reg. No. 64-19-7) is known as ethanoic acid. It occurs naturally in plant and animal tissues. It is produced by fermentation...

  17. 21 CFR 184.1005 - Acetic acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acetic acid. 184.1005 Section 184.1005 Food and... Substances Affirmed as GRAS § 184.1005 Acetic acid. (a) Acetic acid (C2H4O2, CAS Reg. No. 64-19-7) is known as ethanoic acid. It occurs naturally in plant and animal tissues. It is produced by fermentation...

  18. Zeolite membrane application in hydrocarbon processing

    SciTech Connect

    Suzuki, H.

    1988-06-01

    Zeolites are of great importance in hydrocarbon processing either as adsorbents or catalysts. This paper presents a research since 1973 about the transformation of zeolite into membrane zeolite, that dramatically contributes to the free world of peace and prosperity. Commercial and organic membranes are of two categories: anisotropic membrane, e.g. cellulose acetate, and composite membrane, e.g. plasma {und in}-{und situ} polymerization on polysulfone support. Zeolite membrane belongs to the latter category, zeolite {und in}-{und situ} hydrothermalization on porous glass. Basically zeolite membrane is consisted of three groups: (1) eight-oxygen ring window, zeolite A, (2) ten-oxygen ring window, Pentasil, and (3) twelve-oxygen ring window, Faujasite. The technology of zeolite membrane synthesis and subsequent treatment is almost transferred from the one applied to powder zeolites. Zeolite membrane is expected to play a major role in the field of hydrocarbon processing, that is, PSA, Distillation/Extraction, and Catalytic Reactions.

  19. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium acetate. 184.1721 Section 184.1721 Food and... Substances Affirmed as GRAS § 184.1721 Sodium acetate. (a) Sodium acetate (C2H3O2Na, CAS Reg. No. 127-09-3 or C2H3O2Na·3H2O, CAS Reg. No. 6131-90-4) is the sodium salt of acetic acid and occurs naturally in plant...

  20. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium acetate. 184.1721 Section 184.1721 Food and... Substances Affirmed as GRAS § 184.1721 Sodium acetate. (a) Sodium acetate (C2H3O2Na, CAS Reg. No. 127-09-3 or C2H3O2Na·3H2O, CAS Reg. No. 6131-90-4) is the sodium salt of acetic acid and occurs naturally in plant...

  1. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium acetate. 184.1721 Section 184.1721 Food and... Substances Affirmed as GRAS § 184.1721 Sodium acetate. (a) Sodium acetate (C2H3O2Na, CAS Reg. No. 127-09-3 or C2H3O2Na·3H2O, CAS Reg. No. 6131-90-4) is the sodium salt of acetic acid and occurs naturally in plant...

  2. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium acetate. 184.1721 Section 184.1721 Food and... Substances Affirmed as GRAS § 184.1721 Sodium acetate. (a) Sodium acetate (C2H3O2Na, CAS Reg. No. 127-09-3 or C2H3O2Na·3H2O, CAS Reg. No. 6131-90-4) is the sodium salt of acetic acid and occurs naturally in plant...

  3. 21 CFR 862.2485 - Electrophoresis apparatus for clinical use.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electrophoresis apparatus for clinical use. 862... Instruments § 862.2485 Electrophoresis apparatus for clinical use. (a) Identification. An electrophoresis apparatus for clinical use is a device intended to separate molecules or particles, including...

  4. 21 CFR 862.2485 - Electrophoresis apparatus for clinical use.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Electrophoresis apparatus for clinical use. 862... Instruments § 862.2485 Electrophoresis apparatus for clinical use. (a) Identification. An electrophoresis apparatus for clinical use is a device intended to separate molecules or particles, including...

  5. Extractive fermentation of acetic acid

    SciTech Connect

    Busche, R.M.

    1991-12-31

    In this technoeconomic evaluation of the manufacture of acetic acid by fermentation, the use of the bacterium: Acetobacter suboxydans from the old vinegar process was compared with expected performance of the newer Clostridium thermoaceticum bacterium. Both systems were projected to operate as immobilized cells in a continuous, fluidized bed bioreactor, using solvent extraction to recover the product. Acetobacter metabolizes ethanol aerobically to produce acid at 100 g/L in a low pH medium. This ensures that the product is in the form of a concentrated extractable free acid, rather than as an unextractable salt. Unfortunately, yields from glucose by way of the ethanol fermentation are poor, but near the biological limits of the organisms involved. Conversely, C. thermoaceticum is a thermophilic anaerobe that operates at high fermentation rates on glucose at neutral pH to produce acetate salts directly in substantially quantitative yields. However, it is severely inhibited by product, which restricts concentration to a dilute 20 g/L. An improved Acetobacter system operating with recycled cells at 50 g/L appears capable of producing acid at $0.38/lb, as compared with a $0.29/lb price for synthetic acid. However, this system has only a limited margin for process improvement. The present Clostridium system cannot compete, since the required selling price would be $0.42/lb. However, if the organism could be adapted to tolerate higher product concentrations at acid pH, selling price could be reduced to $0.22/lb, or about 80% of the price of synthetic acid.

  6. Hereditary spherocytosis, elliptocytosis, and other red cell membrane disorders.

    PubMed

    Da Costa, Lydie; Galimand, Julie; Fenneteau, Odile; Mohandas, Narla

    2013-07-01

    Hereditary spherocytosis and elliptocytosis are the two most common inherited red cell membrane disorders resulting from mutations in genes encoding various red cell membrane and skeletal proteins. Red cell membrane, a composite structure composed of lipid bilayer linked to spectrin-based membrane skeleton is responsible for the unique features of flexibility and mechanical stability of the cell. Defects in various proteins involved in linking the lipid bilayer to membrane skeleton result in loss in membrane cohesion leading to surface area loss and hereditary spherocytosis while defects in proteins involved in lateral interactions of the spectrin-based skeleton lead to decreased mechanical stability, membrane fragmentation and hereditary elliptocytosis. The disease severity is primarily dependent on the extent of membrane surface area loss. Both these diseases can be readily diagnosed by various laboratory approaches that include red blood cell cytology, flow cytometry, ektacytometry, electrophoresis of the red cell membrane proteins, and mutational analysis of gene encoding red cell membrane proteins.

  7. Electrokinetics of nanoparticle gel-electrophoresis.

    PubMed

    Hill, Reghan J

    2016-09-28

    Gel-electrophoresis has been demonstrated in recent decades to successfully sort a great variety of nanoparticles according to their size, charge, surface chemistry, and corona architecture. However, quantitative theoretical interpetations have been limited by the number and complexity of factors that influence particle migration. Theoretical models have been fragmented and incomplete with respect to their counterparts for free-solution electrophoresis. This paper unifies electrokinetic models that address complex nanoparticle corona architectures, corona and gel charge regulation (e.g., by the local pH), multi-component electrolytes, and non-linear electrostatics and relaxation effects. By comprehensively addressing the electrokinetic aspects of the more general gel-electrophoresis problem, in which short-ranged steric interactions are significant, a stage is set to better focus on the physicochemical and steric factors. In this manner, it is envisioned that noparticle gel-electrophoresis may eventually be advanced from a nanoparticle-characterization tool to one that explicitly probes the short-ranged interactions of nanoparticles with soft networks, such as synthetic gels and biological tissues. In this paper, calculations are undertaken that identify a generalized Hückel limit for nanoparticles in low-conductivity gels, and a new Smoluchowski limit for polyelectrolyte-coated particles in high-conductivity gels that is independent of the gel permeability. Also of fundamental interest is a finite, albeit small, electrophoretic mobility for uncharged particles in charged gels. Electrophoretic mobilities and drag coefficients (with electroviscous effects) for nanoparticles bearing non-uniform coronas show that relaxation effects are typically weak for the small nanoparticles (radius ≈3-10 nm) to which gel-electrophoresis has customarily been applied, but are profound for the larger nanoparticles (radius ≳ 40 nm in low conductivity gels) to which passivated gel-electrophoresis

  8. Use of acetate for enrichment of electrochemically active microorganisms and their 16S rDNA analyses.

    PubMed

    Lee, Jiyoung; Phung, Nguyet Thu; Chang, In Seop; Kim, Byung Hong; Sung, Ha Chin

    2003-06-27

    A fuel cell-type electrochemical device has been used to enrich microbes oxidizing acetate with concomitant electricity generation without using an electron mediator from activated sludge. The device generated a stable current of around 5 mA with complete oxidation of 5 mM acetate at the hydraulic retention time of 2.5 h after 4 weeks of enrichment. Over 70% of electrons available from acetate oxidation was recovered as current. Carbon monoxide or hydrogen did not influence acetate oxidation or current generation from the microbial fuel cell (MFC). Denaturing gradient gel electrophoresis showed that DNA extracted from the acetate-enriched MFC had different 16S rDNA patterns from those of sludge or glucose+glutamate-enriched MFCs. Nearly complete 16S rDNA sequence analyses showed that diverse bacteria were enriched in the MFC fed with acetate. Electron microscopic observations showed biofilm developed on the electrode, but not microbial clumps observed in MFCs fed with complex fuel such as glucose and wastewater from a corn-processing factory.

  9. Enhancement of acetyl xylan esterase activity on cellulose acetate through fusion to a family 3 cellulose binding module.

    PubMed

    Mai-Gisondi, Galina; Turunen, Ossi; Pastinen, Ossi; Pahimanolis, Nikolaos; Master, Emma R

    2015-11-01

    The current study investigates the potential to increase the activity of a family 1 carbohydrate esterase on cellulose acetate through fusion to a family 3 carbohydrate binding module (CBM). Specifically, CtCBM3 from Clostridium thermocellum was fused to the carboxyl terminus of the acetyl xylan esterase (AnAXE) from Aspergillus nidulans, and active forms of both AnAXE and AnAXE-CtCBM3 were produced in Pichia pastoris. CtCBM3 fusion had negligible impact on the thermostability or regioselectivity of AnAXE; activities towards acetylated corncob xylan, 4-methylumbelliferyl acetate, p-nitrophenyl acetate, and cellobiose octaacetate were also unchanged. By contrast, the activity of AnAXE-CtCBM3 on cellulose acetate increased by two to four times over 24 h, with greater differences observed at earlier time points. Binding studies using microcrystalline cellulose (Avicel) and a commercial source of cellulose acetate confirmed functional production of the CtCBM3 domain; affinity gel electrophoresis using acetylated xylan also verified the selectivity of CtCBM3 binding to cellulose. Notably, gains in enzyme activity on cellulose acetate appeared to exceed gains in substrate binding, suggesting that fusion to CtCBM3 increases functional associations between the enzyme and insoluble, high molecular weight cellulosic substrates.

  10. Mechanisms underlying the transport and intracellular metabolism of acetic acid in the presence of glucose in the yeast Zygosaccharomyces bailii.

    PubMed

    Sousa, M J; Rodrigues, F; Côrte-Real, M; Leão, C

    1998-03-01

    Zygosaccharomyces bailii ISA 1307 displays biphasic growth in a medium containing a mixture of glucose (0.5%, w/v) and acetic acid (0.5%, w/v), pH 5.0 and 3.0. In cells harvested during the first growth phase, no activity of a mediated acetic acid transport system was found. Incubation of these cells in phosphate buffer with cycloheximide for 1 h restored activity of an acetic acid carrier which behaved as the one present in glucose-grown cells. These results indicated that the acetic acid carrier is probably present in cells from the first growth phase of the mixed medium but its activity was affected by the presence of acetic acid in the culture medium. In glucose-grown cells, after incubation in phosphate buffer with glucose and acetic acid, the activity of the acetic acid carrier decreased significantly with increased acid concentration in the incubation buffer. At acid concentrations above 16.7 mM, no significant carrier activity was detectable. Furthermore, the intracellular acid concentration increased with the extracellular one and was inversely correlated with the activity of the acetic acid carrier, suggesting the involvement of a feedback inhibition mechanism in the regulation of the carrier. During biphasic growth, the first phase corresponded to a simultaneous consumption of glucose and acetic acid, and the second to the utilization of the remaining acid. The enzyme acetyl-CoA synthetase was active in both growth phases, even in the presence of glucose. Activity of isocitrate lyase and phosphoenolpyruvate carboxykinase was found only in acetic-acid-grown cells. Thus it appears that both membrane transport and acetyl-CoA synthetase and their regulation are important for Z. bailii to metabolize acetic acid in the presence of glucose. This fact correlates with the high resistance of this yeast to environments with mixtures of sugars and acetic acid such as those often present during wine fermentation.

  11. Determination of egg white lysozyme by on-line coupled capillary isotachophoresis with capillary zone electrophoresis.

    PubMed

    Kvasnicka, Frantisek

    2003-03-01

    An on-line coupled capillary isotachophoresis - capillary zone electrophoresis method for the determination of lysozyme in selected food products is described. The optimized electrolyte system consisted of 10 mM NH(4)OH + 20 mM acetic acid (leading electrolyte), 5 mM epsilon -aminocaproic acid +5 mM acetic acid (terminating electrolyte), and 20 mM epsilon -aminocaproic acid +5 mM acetic acid +0.1% m/v hydroxypropylmethylcellulose (background electrolyte). A clear separation of lysozyme from other components of acidic sample extract was achieved within 15 min. Method characteristics, i.e., linearity (0-50 micrograms/mL), accuracy (recovery 96+/-5%), intra-assay (3.8%), quantification limit (1 microgram/ml), and detection limit (0.25 microgram/mL) were determined. Low laboriousness, sufficient sensitivity and low running costs are important attributes of this method. The developed method is suitable for the quantification of the egg content in egg pasta.

  12. Comparative proteomics and difference gel electrophoresis.

    PubMed

    Minden, Jonathan

    2007-12-01

    The goal of comparative proteomics is to analyze proteome changes in response to development, disease, or environment. This is a two-step process in which proteins within cellular extracts are first fractionated to reduce sample complexity, and then the proteins are identified by mass spectrometry. Two-dimensional electrophoresis (2DE) is the long-time standard for protein separation, but it has suffered from poor reproducibility and limited sensitivity. Difference gel electrophoresis (DIGE), in which two protein samples are separately labeled with different fluorescent dyes and then co-electrophoresed on the same 2DE gel, was developed to overcome the reproducibility and sensitivity limitations. In this essay, I discuss the principles of comparative proteomics and the development of DIGE.

  13. Theory of electrophoresis: fate of one equation.

    PubMed

    Gas, Bohuslav

    2009-06-01

    Electrophoresis utilizes a difference in movement of charged species in a separation channel or space for their spatial separation. A basic partial differential equation that results from the balance laws of continuous processes in separation sciences is the nonlinear conservation law or the continuity equation. Attempts at its analytical solution in electrophoresis go back to Kohlrausch's days. The present paper (i) reviews derivation of conservation functions from the conservation law as appeared chronologically, (ii) deals with theory of moving boundary equations and, mainly, (iii) presents the linear theory of eigenmobilities. It shows that a basic solution of the linearized continuity equations is a set of traveling waves. In particular cases the continuity equation can have a resonance solution that leads in practice to schizophrenic dispersion of peaks or a chaotic solution, which causes oscillation of electrolyte solutions.

  14. Static free-fluid electrophoresis in space

    NASA Technical Reports Server (NTRS)

    Snyder, R. S.; Allen, R. E.

    1977-01-01

    The weightless environment onboard spacecraft in drifting flight has provided a unique opportunity to do experiments that cannot be done on the ground. High resolution free-fluid electrophoresis of particles proposed in the late 1960s to take advantage of reduced gravity began with brief experiments done during two Apollo flights. The recent Apollo Soyuz Test Project mission had two major experiments that accomplished the separation of viable biological cells. Experiments now are being planned for the Space Shuttle which will attempt to achieve high resolution of the separated species by using zone electrophoresis. These experiments will return a quantity sufficient for laboratory testing and establish the potential of fractionation and purification of biological materials in space.

  15. Mathematical Models of Continuous Flow Electrophoresis

    NASA Technical Reports Server (NTRS)

    Saville, D. A.; Snyder, R. S.

    1985-01-01

    Development of high resolution continuous flow electrophoresis devices ultimately requires comprehensive understanding of the ways various phenomena and processes facilitate or hinder separation. A comprehensive model of the actual three dimensional flow, temperature and electric fields was developed to provide guidance in the design of electrophoresis chambers for specific tasks and means of interpreting test data on a given chamber. Part of the process of model development includes experimental and theoretical studies of hydrodynamic stability. This is necessary to understand the origin of mixing flows observed with wide gap gravitational effects. To insure that the model accurately reflects the flow field and particle motion requires extensive experimental work. Another part of the investigation is concerned with the behavior of concentrated sample suspensions with regard to sample stream stability particle-particle interactions which might affect separation in an electric field, especially at high field strengths. Mathematical models will be developed and tested to establish the roles of the various interactions.

  16. Fish Muscle Proteins: Extraction, Quantitation, and Electrophoresis

    NASA Astrophysics Data System (ADS)

    Smith, Denise

    Electrophoresis can be used to separate and visualize proteins. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), proteins are separated based on size. When protein samples are applied to such gels, it is usually necessary to know the protein content of the sample. This makes it possible to apply a volume of sample to the gel such that samples have a comparable amount of total protein. While it is possible to use an official method of protein analysis (e.g., Kjeldahl, N combustion) for such an application, it often is convenient to use a rapid spectroscopic protein analysis that requires only a small amount of sample. The bicinchoninic acid (BCA) assay method will be used for this purpose.

  17. A new approach to electrophoresis in space

    NASA Technical Reports Server (NTRS)

    Snyder, Robert S.; Rhodes, Percy H.

    1990-01-01

    Previous electrophoresis experiments performed in space are reviewed. There is sufficient data available from the results of these experiments to show that they were designed with incomplete knowledge of the fluid dynamics of the process including electrohydrodynamics. Redesigning laboratory chambers and operating procedures developed on Earth for space without understanding both the advantages and disadvantages of the microgravity environment has yielded poor separations of both cells and proteins. However, electrophoreris is still an important separation tool in the laboratory and thermal convection does limit its performance. Thus, there is a justification for electrophoresis but the emphasis of future space experiments must be directed toward basic research with model experiments to understand the microgravity environment and fluid analysis to test the basic principles of the process.

  18. Numerical simulation of electrophoresis separation processes

    NASA Technical Reports Server (NTRS)

    Ganjoo, D. K.; Tezduyar, T. E.

    1986-01-01

    A new Petrov-Galerkin finite element formulation has been proposed for transient convection-diffusion problems. Most Petrov-Galerkin formulations take into account the spatial discretization, and the weighting functions so developed give satisfactory solutions for steady state problems. Though these schemes can be used for transient problems, there is scope for improvement. The schemes proposed here, which consider temporal as well as spatial discretization, provide improved solutions. Electrophoresis, which involves the motion of charged entities under the influence of an applied electric field, is governed by equations similiar to those encountered in fluid flow problems, i.e., transient convection-diffusion equations. Test problems are solved in electrophoresis and fluid flow. The results obtained are satisfactory. It is also expected that these schemes, suitably adapted, will improve the numerical solutions of the compressible Euler and the Navier-Stokes equations.

  19. Electrokinetic Flow and Dispersion in Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

    Ghosal, Sandip

    2006-01-01

    Electrophoretic separation of a mixture of chemical species is a fundamental technique of great usefulness in biology, health care, and forensics. In capillary electrophoresis (which has evolved from its predecessor, slab-gel electrophoresis), the sample migrates through a single microcapillary instead of through the network of pores in a gel. A fundamental design problem is to minimize dispersion in the separation direction. Molecular diffusion is inevitable and sets a theoretical limit on the best separation that can be achieved. But in practice, there are a number of effects arising out of the interplay between fluid flow, chemistry, thermal effects, and electric fields that result in enhanced dispersion. This paper reviews the subject of fluid flow in such capillary microchannels and examines the various causes of enhanced dispersion that limit the efficiency of separation.

  20. Manufacturing Ethyl Acetate From Fermentation Ethanol

    NASA Technical Reports Server (NTRS)

    Rohatgi, Naresh K.; Ingham, John D.

    1991-01-01

    Conceptual process uses dilute product of fermentation instead of concentrated ethanol. Low-concentration ethanol, extracted by vacuum from fermentation tank, and acetic acid constitutes feedstock for catalytic reaction. Product of reaction goes through steps that increases ethyl acetate content to 93 percent by weight. To conserve energy, heat exchangers recycle waste heat to preheat process streams at various points.

  1. Electron transfer induced fragmentation of acetic acid

    NASA Astrophysics Data System (ADS)

    Ferreira da Silva, F.; Meneses, G.; Almeida, D.; Limão-Vieira, P.

    2014-04-01

    We present negative ion formation driven by electron transfer in atom (K) molecule (acetic acid) collisions. Acetic acid has been found in the interstellar medium, is also considered a biological related compound and as such studying low energy electron interactions will bring new insights as far as induced chemistry is concerned.

  2. CELLULOSE NITRATE-ACETATE MIXED ESTERS

    DTIC Science & Technology

    cellulose acetate . The degree of polymerization of the products, as estimated from viscosity data, shows the occurrence of chain degradation for both...mixed esters showed tensile strength at least comparable to that of films of cellulose nitrate or cellulose acetate . The impact sensitivity of the

  3. A method and apparatus for continuous electrophoresis

    SciTech Connect

    Watson, J.S.

    1990-01-01

    A method and apparatus for conducting continuous separation of substances by electrophoresis are disclosed. The process involves electrophoretic separation combined with couette flow in a thin volume defined by opposing surfaces. By alternating the polarity of the applied potential and producing reciprocating short rotations of at least on of the surfaces relative to the other, small increments of separation accumulate to cause substantial, useful segregation of electrophoretically separable components in a continuous flow system.

  4. Capillary zone electrophoresis-mass spectrometer interface

    DOEpatents

    D'Silva, Arthur

    1996-08-06

    A device for providing equal electrical potential between two loci unconnected by solid or liquid electrical conducts is provided. The device comprises a first electrical conducting terminal, a second electrical conducting terminal connected to the first terminal by a rigid dielectric structure, and an electrically conducting gas contacting the first and second terminals. This device is particularly suitable for application in the electrospray ionization interface between a capillary zone electrophoresis apparatus and a mass spectrometer.

  5. Capillary zone electrophoresis-mass spectrometer interface

    DOEpatents

    D`Silva, A.

    1996-08-06

    A device for providing equal electrical potential between two loci unconnected by solid or liquid electrical conductors is provided. The device comprises a first electrical conducting terminal, a second electrical conducting terminal connected to the first terminal by a rigid dielectric structure, and an electrically conducting gas contacting the first and second terminals. This device is particularly suitable for application in the electrospray ionization interface between a capillary zone electrophoresis apparatus and a mass spectrometer. 1 fig.

  6. Method and apparatus for continuous electrophoresis

    DOEpatents

    Watson, Jack S.

    1992-01-01

    A method and apparatus for conducting continuous separation of substances by electrophoresis are disclosed. The process involves electrophoretic separation combined with couette flow in a thin volume defined by opposing surfaces. By alternating the polarity of the applied potential and producing reciprocating short rotations of at least one of the surfaces relative to the other, small increments of separation accumulate to cause substantial, useful segregation of electrophoretically separable components in a continuous flow system.

  7. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, Edward S.; Taylor, John A.

    1996-03-12

    A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis.

  8. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, Edward S.; Taylor, John A.

    1994-06-28

    A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis.

  9. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, E.S.; Taylor, J.A.

    1994-06-28

    A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis. 14 figures.

  10. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, E.S.; Taylor, J.A.

    1996-03-12

    A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis. 14 figs.

  11. Commander prepares glass columns for electrophoresis experiment

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Commander Jack Lousma prepares on of the glass columns for the electrophoresis test in the middeck area of the Columbia. The experiment, deployed in an L-shaped mode in upper right corner, consists of the processing unit with glass columns in which the separation takes place; a camera (partially obscurred by Lousma's face) to document the process; and a cryogenic freezer to freeze and store the samples after separation.

  12. Portable electrophoresis apparatus using minimum electrolyte

    NASA Technical Reports Server (NTRS)

    Stevens, M. R.; Vickers, J. M. (Inventor)

    1976-01-01

    An electrophoresis unit for use in conducting electrophoretic analysis of specimens is described. The unit includes a sealable container in which a substrate mounted specimen is suspended in an electrolytic vapor. A heating unit is employed to heat a supply of electrolyte to produce the vapor. The substrate is suspended within the container by being attached between a pair of clips which also serve as electrodes to which a direct current power source may be connected.

  13. Detection of biclonal gammopathy by capillary zone electrophoresis in a cat and a dog with plasma cell neoplasia.

    PubMed

    Facchini, Roberto Vailati; Bertazzolo, Walter; Zuliani, Davide; Bonfanti, Ugo; Caldin, Marco; Avallone, Giancarlo; Roccabianca, Paola

    2010-12-01

    Gammopathies associated with plasma cell neoplasms in a 15-year-old female spayed domestic shorthaired cat and a 9-year-old female spayed Rottweiler dog were evaluated by serum protein electrophoresis. In the cat, the plasma cell neoplasm was found in the liver and spleen, and an evaluable sample of bone marrow was not obtained. Some of the plasma cells had the morphologic appearance of flame cells. The paraprotein was confirmed as IgG based on agar gel immunodiffusion precipitation and both immunocytochemical and immunohistochemical staining. The dog had multiple myeloma with production of IgG and IgA paraproteins. In both cases, serum proteins were evaluated by 2 methods of protein electrophoresis: cellulose acetate electrophoresis (CAE) and capillary zone electrophoresis (CZE). In the cat and the dog, CAE showed a single large oligoclonal-like peak, which occurred in the γ-region in the cat and the β-γ-region in the dog, whereas CZE showed a biclonal gammopathy with 2 very close narrow spikes in the γ- and β-γ-regions in the cat and dog, respectively. In selected cases, CZE may be more effective than routine CAE in distinguishing oligoclonal from monoclonal or biclonal paraproteinemia.

  14. The role of ion electrophoresis in electroporation-mediated molecular delivery

    NASA Astrophysics Data System (ADS)

    Li, Jianbo; Lin, Hao

    2009-11-01

    Electroporation is a widely applied technique to deliver active molecules into the cellular compartment, to perform a variety of tasks such as gene therapy and directed stem cell differentiation. In this technique, an electric field transiently permeabilizes the cellular membrane to facilitate molecular exchange. While the permeabilization process is relatively well-understood, the transport mechanisms for molecular delivery are still under debate. In this work, the role of ion electrophoresis in electroporation-mediated molecular delivery is investigated using numerical simulations. The result indicates that ion electrophoresis is the dominant mode of transport in the delivery of small charged molecules. Furthermore, the achievable intracellular concentration is strongly influenced by the conductivity difference between the cytoplasm and the buffer, a phenomenon known as ``field-amplified sample stacking''. The result agrees well with the fluorescence measurement by Gabriel and Teissi'e (1999), and suggests a new possibility to simultaneously improve cell viability and efficiency in electroporation-mediated molecular delivery.

  15. Detection of glycoproteins in the Acanthamoeba plasma membrane

    SciTech Connect

    Paatero, G.I.L. ); Gahmberg, C.G. )

    1988-11-01

    In the present study the authors have shown that glycoproteins are present in the plasma membrane of Acanthamoeba castellanii by utilizing different radioactive labeling techniques. Plasma membrane proteins in the amoeba were iodinated by {sup 125}I-lactoperoxidase labeling and the solubilized radiolabeled glycoproteins were separated by lectin-Sepharose affinity chromatography followed by polyacrylamide gel electrophoresis. The periodate/NaB{sup 3}H{sub 4} and galactose oxidase/NaB{sup 3}H{sub 4} labeling techniques were used for labeling of surface carbohydrates in the amoeba. Several surface-labeled glycoproteins were observed in addition to a diffusely labeled region with M{sub r} of 55,000-75,000 seen on electrophoresis, which could represent glycolipids. The presence of glycoproteins in the plasma membrane of Acanthamoeba castellanii was confirmed by metabolic labeling with ({sup 35}S)methionine followed by lectin-Sepharose affinity chromatography and polyacrylamide gel electrophoresis.

  16. Biochemical characteristics of the outer membranes of plant mitochondria.

    PubMed

    Mannella, C A; Bonner, W D

    1975-12-01

    Like the outer membranes of liver mitochondria, those of plant mitochondria are impermeable to cytochrome c when intact and can be ruptured by osmotic shock. Isolated plant outer mitochondrial membranes are also similar to the corresponding liver membranes in terms of phospholipid and sterol content. Sodium dodecyl sulfate-polyacrylamide gradient gel electrophoresis experiments indicate that a single class of proteins (apparent molecular weight 30 000) comprises the bulk of the plant outer membrane protein. There are also considerable amounts of polysaccharide associated with these membranes, which may contribute to their osmotic stability.

  17. Drug resistance marker-aided genome shuffling to improve acetic acid tolerance in Saccharomyces cerevisiae.

    PubMed

    Zheng, Dao-Qiong; Wu, Xue-Chang; Wang, Pin-Mei; Chi, Xiao-Qin; Tao, Xiang-Lin; Li, Ping; Jiang, Xin-Hang; Zhao, Yu-Hua

    2011-03-01

    Acetic acid existing in a culture medium is one of the most limiting constraints in yeast growth and viability during ethanol fermentation. To improve acetic acid tolerance in Saccharomyces cerevisiae strains, a drug resistance marker-aided genome shuffling approach with higher screen efficiency of shuffled mutants was developed in this work. Through two rounds of genome shuffling of ultraviolet mutants derived from the original strain 308, we obtained a shuffled strain YZ2, which shows significantly faster growth and higher cell viability under acetic acid stress. Ethanol production of YZ2 (within 60 h) was 21.6% higher than that of 308 when 0.5% (v/v) acetic acid was added to fermentation medium. Membrane integrity, higher in vivo activity of the H+-ATPase, and lower oxidative damage after acetic acid treatment are the possible reasons for the acetic acid-tolerance phenotype of YZ2. These results indicated that this novel genome shuffling approach is powerful to rapidly improve the complex traits of industrial yeast strains.

  18. Refinery hydrogen recovery with sepharex membrane systems

    SciTech Connect

    Schnell, W.J.; Houston, C.D.

    1985-03-01

    Gas separation by membranes is discussed, and presented to be an economically viable process. Commercial installation of membrane systems has been made for hydrogen recovery in refineries and ammonia plants and for CO/sub 2/ removal from various gas streams. The process described in this paper utilizes a flat-sheet cellulose acetate membrane fabricated into a spiral wound element configuration. An illustration of the membrane, named Separex, is provided. These membranes exhibit long-time stability in refinery H/sub 2/ recovery applications even under harsh operating conditions. The successful operation of this system demonstrates the commercial capability of Separex membranes. A comparison with PSA for hydrogen purification shows that membrane systems offer a substantially lower hydrogen production cost and an increase in hydrogen recovery.

  19. Electrophoretic extraction of proteins from two-dimensional electrophoresis gel spots

    SciTech Connect

    Zhang, J.S.; Giometti, C.S.; Tollaksen, S.L.

    1989-04-25

    After two-dimensional electrophoresis of proteins or the like, resulting in a polyacrylamide gel slab having a pattern of protein gel spots thereon, an individual protein gel spot is cored out from the slab, to form a gel spot core which is placed in an extraction tube, with a dialysis membrane across the lower and of the tube. Replicate gel spots can be cored out from replicate gel slabs and placed in the extraction tube. Molten agarose gel is poured into the extraction tube where the agarose gel hardens to form an immobilizing gel, covering the gel spot cores. The upper end portion of the extraction tube is filled with a volume of buffer solution, and the upper end is closed by another dialysis membrane. Upper and lower bodies of a buffer solution are brought into contact with the upper and lower membranes and are provided with electrodes connected to the positive and negative terminals of a DC power supply, thereby producing an electrical current which flows through the upper membrane, the volume of buffer solution, the agarose, the gel spot cores and the lower membrane. The current causes the proteins to be extracted electrophoretically from the gel spot cores, so that the extracted proteins accumulate and are contained in the space between the agarose gel and the upper membrane. A high percentage extraction of proteins is achieved. The extracted proteins can be removed and subjected to partial digestion by trypsin or the like, followed by two-dimensional electrophoresis, resulting in a gel slab having a pattern of peptide gel spots which can be cored out and subjected to electrophoretic extraction to extract individual peptides.

  20. Electrophoretic extraction of proteins from two-dimensional electrophoresis gel spots

    SciTech Connect

    Zhang, Jian-Shi; Giometti, Carol S.; Tollaksen, Sandra L.

    1989-01-01

    After two-dimensional electrophoresis of proteins or the like, resulting in a polyacrylamide gel slab having a pattern of protein gel spots thereon, an individual protein gel spot is cored out from the slab, to form a gel spot core which is placed in an extraction tube, with a dialysis membrane across the lower end of the tube. Replicate gel spots can be cored out from replicate gel slabs and placed in the extraction tube. Molten agarose gel is poured into the extraction tube where the agarose gel hardens to form an immobilizing gel, covering the gel spot cores. The upper end portion of the extraction tube is filled with a volume of buffer solution, and the upper end is closed by another dialysis membrane. Upper and lower bodies of a buffer solution are brought into contact with the upper and lower membranes and are provided with electrodes connected to the positive and negative terminals of a DC power supply, thereby producing an electrical current which flows through the upper membrane, the volume of buffer solution, the agarose, the gel spot cores and the lower membrane. The current causes the proteins to be extracted electrophoretically from the gel spot cores, so that the extracted proteins accumulate and are contained in the space between the agarose gel and the upper membrane. A high percentage extraction of proteins is achieved. The extracted proteins can be removed and subjected to partial digestion by trypsin or the like, followed by two-dimensional electrophoresis, resulting in a gel slab having a pattern of peptide gel spots which can be cored out and subjected to electrophoretic extraction to extract individual peptides.

  1. Depomedroxyprogesterone acetate for hot flashes.

    PubMed

    Barton, Debra; Loprinzi, Charles; Quella, Susan; Sloan, Jeff; Pruthi, Sandya; Novotny, Paul

    2002-12-01

    To evaluate the efficacy of a long-acting preparation of medroxyprogesterone acetate for hot flash management, 3 men receiving androgen ablation therapy for prostate cancer and 15 women with a history of breast cancer were treated as part of clinical practice with three biweekly intramuscular injections of 500 mg depomedroxyprogesterone. A review of hot flash diaries and patient charts were completed to evaluate the effectiveness and tolerability of these injections for managing hot flashes. Treatment was associated with an approximate 90% decrease in hot flashes (95% CI 82-97%). Daily hot flash frequency decreased from a mean of 10.9 on the first day of treatment (95% CI 8.0-13.8 hot flashes per day) to a mean of 1.1 hot flashes 6 weeks later (95% CI 0.5-1.8 hot flashes) and to a mean of 0.7 hot flashes 12 weeks following therapy initiation (95% CI 0.1-1.2). Improvement in the hot flashes remained for months after discontinuing the injections in many patients. Reported side effects were minimal. This experience suggests that treatment with depomedroxyprogesterone may be an effective and well-tolerated option for the treatment of hot flashes.

  2. Predominant contribution of syntrophic acetate oxidation to thermophilic methane formation at high acetate concentrations.

    PubMed

    Hao, Li-Ping; Lü, Fan; He, Pin-Jing; Li, Lei; Shao, Li-Ming

    2011-01-15

    To quantify the contribution of syntrophic acetate oxidation to thermophilic anaerobic methanogenesis under the stressed condition induced by acidification, the methanogenic conversion process of 100 mmol/L acetate was monitored simultaneously by using isotopic tracing and selective inhibition techniques, supplemented with the analysis of unculturable microorganisms. Both quantitative methods demonstrated that, in the presence of aceticlastic and hydrogenotrophic methanogens, a large percentage of methane (up to 89%) was initially derived from CO(2) reduction, indicating the predominant contribution of the syntrophic acetate oxidation pathway to acetate degradation at high acid concentrations. A temporal decrease of the fraction of hydrogenotrophic methanogenesis from more than 60% to less than 40% reflected the gradual prevalence of the aceticlastic methanogenesis pathway along with the reduction of acetate. This apparent discrimination of acetate methanization pathways highlighted the importance of the syntrophic acetate-oxidizing bacteria to initialize methanogenesis from high organic loadings.

  3. Membrane stabilizer

    DOEpatents

    Mingenbach, W.A.

    1988-02-09

    A device is provided for stabilizing a flexible membrane secured within a frame, wherein a plurality of elongated arms are disposed radially from a central hub which penetrates the membrane, said arms imposing alternately against opposite sides of the membrane, thus warping and tensioning the membrane into a condition of improved stability. The membrane may be an opaque or translucent sheet or other material. 10 figs.

  4. A specialized citric acid cycle requiring succinyl-coenzyme A (CoA):acetate CoA-transferase (AarC) confers acetic acid resistance on the acidophile Acetobacter aceti.

    PubMed

    Mullins, Elwood A; Francois, Julie A; Kappock, T Joseph

    2008-07-01

    Microbes tailor macromolecules and metabolism to overcome specific environmental challenges. Acetic acid bacteria perform the aerobic oxidation of ethanol to acetic acid and are generally resistant to high levels of these two membrane-permeable poisons. The citric acid cycle (CAC) is linked to acetic acid resistance in Acetobacter aceti by several observations, among them the oxidation of acetate to CO2 by highly resistant acetic acid bacteria and the previously unexplained role of A. aceti citrate synthase (AarA) in acetic acid resistance at a low pH. Here we assign specific biochemical roles to the other components of the A. aceti strain 1023 aarABC region. AarC is succinyl-coenzyme A (CoA):acetate CoA-transferase, which replaces succinyl-CoA synthetase in a variant CAC. This new bypass appears to reduce metabolic demand for free CoA, reliance upon nucleotide pools, and the likely effect of variable cytoplasmic pH upon CAC flux. The putative aarB gene is reassigned to SixA, a known activator of CAC flux. Carbon overflow pathways are triggered in many bacteria during metabolic limitation, which typically leads to the production and diffusive loss of acetate. Since acetate overflow is not feasible for A. aceti, a CO(2) loss strategy that allows acetic acid removal without substrate-level (de)phosphorylation may instead be employed. All three aar genes, therefore, support flux through a complete but unorthodox CAC that is needed to lower cytoplasmic acetate levels.

  5. Zone electrophoresis in an inner-cooling wide-bore electrophoresis system with UV detection.

    PubMed

    Guo, Yugao; Liu, Danning; Wang, Huaifeng; Yuan, Ruijuan; Bao, James Jianmin

    2008-08-01

    A novel, high-performance wide-bore electrophoresis (WE) system with inner-cooling has been developed. By introducing the mode of a shell and tube heat exchanger into this system to remove Joule heat generated during electrophoresis, it is feasible to extend electrophoresis from the conventional capillary (i.d. <100 microm) to a wide-bore tube (i.d. >1000 microm). The wide tube allows the loading of over 1.0 microL of the sample with an LOD of 3.0 x 10(-4) mg/mL (signal-to-noise ratio, 3:1). Satisfactory separations of model compounds have been achieved on the WE system.

  6. Cellulose Acetate-Poly(N-isopropylacrylamide)-Based Functional Surfaces with Temperature-Triggered Switchable Wettability.

    PubMed

    Ganesh, V Anand; Ranganath, Anupama Sargur; Sridhar, Radhakrishnan; Raut, Hemant Kumar; Jayaraman, Sundaramurthy; Sahay, Rahul; Ramakrishna, Seeram; Baji, Avinash

    2015-07-01

    Temperature-triggered switchable nanofibrous membranes are successfully fabricated from a mixture of cellulose acetate (CA) and poly(N-isopropylacrylamide) (PNIPAM) by employing a single-step direct electrospinning process. These hybrid CA-PNIPAM membranes demonstrate the ability to switch between two wetting states viz. superhydrophilic to highly hydrophobic states upon increasing the temperature. At room temperature (23 °C) CA-PNIPAM nanofibrous membranes exhibit superhydrophilicity, while at elevated temperature (40 °C) the membranes demonstrate hydrophobicity with a static water contact angle greater than 130°. Furthermore, the results here demonstrate that the degree of hydrophobicity of the membranes can be controlled by adjusting the ratio of PNIPAM in the CA-PNIPAM mixture.

  7. Physico-chemical characterization of liposomes and drug substance-liposome interactions in pharmaceutics using capillary electrophoresis and electrokinetic chromatography.

    PubMed

    Franzen, Ulrik; Østergaard, Jesper

    2012-12-07

    Liposomes are self-assembled phospholipid vesicles and have numerous research and therapeutic applications. In the pharmaceutical and biomedical sciences liposomes find use as models of biological membranes, partitioning medium and as drug carriers. The present review addresses the use of capillary electrophoresis and liposome electrokinetic chromatography for the characterization of liposomes in a pharmaceutical context. Capillary electrophoretic techniques have been used for the measurement of electrophoretic mobility, which provides information on liposome surface charge, size and membrane permeability of liposomes. The use of liposome electrokinetic chromatography and capillary electrophoresis for determination of liposome/water partitioning and characterization of drug-liposome interactions is reviewed. A number of studies indicate that capillary electrophoresis may have a role in the characterization of liposome drug delivery systems, e.g., for the investigation of encapsulation efficiency and drug leakage. The well-known characteristics of capillary electrophoresis, i.e., low sample volume requirement, high separation efficiency in aqueous media without a stationary phase, minimal sample preparation, and a high degree of automation, makes it an attractive approach in liposome research.

  8. NUCLEAR MEMBRANES FROM MAMMALIAN LIVER

    PubMed Central

    Franke, Werner W.; Deumling, Barbara; Ermen, Baerbel; Jarasch, Ernst-Dieter; Kleinig, Hans

    1970-01-01

    Nuclear membranes were isolated from rat and pig liver by sonication of highly purified nuclear fractions and subsequent removal of adhering nucleoproteins in a high salt medium. The fractions were examined in the electron microscope by both negative staining and thin sectioning techniques and were found to consist of nuclear envelope fragments of widely varying sizes. Nuclear pore complex constituents still could frequently be recognized. The chemical composition of the nuclear membrane fractions was determined and compared with those of microsomal fractions prepared in parallel. For total nuclei as well as for nuclear membranes and microsomes, various enzyme activities were studied. The results indicate that a similarity exists between both fractions of cytomembranes, nuclear envelope, and endoplasmic reticulum, with respect to their RNA:protein ratio and their content of polar and nonpolar lipids. Both membranous fractions had many proteins in common including some membrane-bound enzymes. Activities in Mg-ATPase and the two examined cytochrome reductases were of the same order of magnitude. The content of cytochrome b5 as well as of P-450 was markedly lower in the nuclear membranes. The nuclear membranes were found to have a higher buoyant density and to be richer in protein. The glucose-6-phosphatase and Na-K-ATPase activities in the nuclear membrane fraction were very low. In the gel electrophoresis, in addition to many common protein bands, some characteristic ones for either microsomal or nuclear membranous material were detected. Significant small amounts of DNA and RNA were found to remain closely associated with the nuclear envelope fragments. Our findings indicate that nuclear and endoplasmic reticulum membranes which are known to be in morphological continuity have, besides a far-reaching similarity, some characteristic differences. PMID:4317731

  9. Oxidation of acetate through reactions of the citric acid cycle by Geobacter sulfurreducens in pure culture and in syntrophic coculture.

    PubMed

    Galushko, A S; Schink, B

    2000-11-01

    Geobacter sulfurreducens strain PCA oxidized acetate to CO2 via citric acid cycle reactions during growth with acetate plus fumarate in pure culture, and with acetate plus nitrate in coculture with Wolinella succinogenes. Acetate was activated by succinyl-CoA:acetate CoA-transferase and also via acetate kinase plus phosphotransacetylase. Citrate was formed by citrate synthase. Soluble isocitrate and malate dehydrogenases NADP+ and NAD+, respectively. Oxidation of 2-oxoglutarate was measured as benzyl viologen reduction and strictly CoA-dependent; a low activity was also observed with NADP+. Succinate dehydrogenase and fumarate ductase both were membrane-bound. Succinate oxidation was coupled to NADP+ reduction whereas fumarate reduction was coupled to NADPH and NADH Coupling of succinate oxidation to NADP+ or cytochrome(s) reduction required an ATP-dependent reversed electron transport. Net ATP synthesis proceeded exclusively through electron transport phosphorylation. During fumarate reduction, both NADPH and NADH delivered reducing equivalents into the electron transport chain, which contained a menaquinone. Overall, acetate oxidation with fumarate proceeded through an open loop of citric acid cycle reactions, excluding succinate dehydrogenase, with fumarate reductase as the key reaction for electron delivery, whereas acetate oxidation in the syntrophic coculture required the complete citric acid cycle.

  10. Acetate in mixotrophic growth medium affects photosystem II in Chlamydomonas reinhardtii and protects against photoinhibition.

    PubMed

    Roach, Thomas; Sedoud, Arezki; Krieger-Liszkay, Anja

    2013-10-01

    Chlamydomonas reinhardtii is a photoautotrophic green alga, which can be grown mixotrophically in acetate-supplemented media (Tris-acetate-phosphate). We show that acetate has a direct effect on photosystem II (PSII). As a consequence, Tris-acetate-phosphate-grown mixotrophic C. reinhardtii cultures are less susceptible to photoinhibition than photoautotrophic cultures when subjected to high light. Spin-trapping electron paramagnetic resonance spectroscopy showed that thylakoids from mixotrophic C. reinhardtii produced less (1)O2 than those from photoautotrophic cultures. The same was observed in vivo by measuring DanePy oxalate fluorescence quenching. Photoinhibition can be induced by the production of (1)O2 originating from charge recombination events in photosystem II, which are governed by the midpoint potentials (Em) of the quinone electron acceptors. Thermoluminescence indicated that the Em of the primary quinone acceptor (QA/QA(-)) of mixotrophic cells was stabilised while the Em of the secondary quinone acceptor (QB/QB(-)) was destabilised, therefore favouring direct non-radiative charge recombination events that do not lead to (1)O2 production. Acetate treatment of photosystem II-enriched membrane fragments from spinach led to the same thermoluminescence shifts as observed in C. reinhardtii, showing that acetate exhibits a direct effect on photosystem II independent from the metabolic state of a cell. A change in the environment of the non-heme iron of acetate-treated photosystem II particles was detected by low temperature electron paramagnetic resonance spectroscopy. We hypothesise that acetate replaces the bicarbonate associated to the non-heme iron and changes the environment of QA and QB affecting photosystem II charge recombination events and photoinhibition.

  11. Lipidomic Profiling of Saccharomyces cerevisiae and Zygosaccharomyces bailii Reveals Critical Changes in Lipid Composition in Response to Acetic Acid Stress

    PubMed Central

    Riezman, Howard; Olsson, Lisbeth; Bettiga, Maurizio

    2013-01-01

    When using microorganisms as cell factories in the production of bio-based fuels or chemicals from lignocellulosic hydrolysate, inhibitory concentrations of acetic acid, released from the biomass, reduce the production rate. The undissociated form of acetic acid enters the cell by passive diffusion across the lipid bilayer, mediating toxic effects inside the cell. In order to elucidate a possible link between lipid composition and acetic acid stress, the present study presents detailed lipidomic profiling of the major lipid species found in the plasma membrane, including glycerophospholipids, sphingolipids and sterols, in Saccharomyces cerevisiae (CEN.PK 113_7D) and Zygosaccharomyces bailii (CBS7555) cultured with acetic acid. Detailed physiological characterization of the response of the two yeasts to acetic acid has also been performed in aerobic batch cultivations using bioreactors. Physiological characterization revealed, as expected, that Z. bailii is more tolerant to acetic acid than S. cerevisiae. Z. bailii grew at acetic acid concentrations above 24 g L−1, while limited growth of S. cerevisiae was observed after 11 h when cultured with only 12 g L−1 acetic acid. Detailed lipidomic profiling using electrospray ionization, multiple-reaction-monitoring mass spectrometry (ESI-MRM-MS) showed remarkable changes in the glycerophospholipid composition of Z. bailii, including an increase in saturated glycerophospholipids and considerable increases in complex sphingolipids in both S. cerevisiae (IPC 6.2×, MIPC 9.1×, M(IP)2C 2.2×) and Z. bailii (IPC 4.9×, MIPC 2.7×, M(IP)2C 2.7×), when cultured with acetic acid. In addition, the basal level of complex sphingolipids was significantly higher in Z. bailii than in S. cerevisiae, further emphasizing the proposed link between lipid saturation, high sphingolipid levels and acetic acid tolerance. The results also suggest that acetic acid tolerance is associated with the ability of a given strain to generate large

  12. Lipidomic profiling of Saccharomyces cerevisiae and Zygosaccharomyces bailii reveals critical changes in lipid composition in response to acetic acid stress.

    PubMed

    Lindberg, Lina; Santos, Aline Xs; Riezman, Howard; Olsson, Lisbeth; Bettiga, Maurizio

    2013-01-01

    When using microorganisms as cell factories in the production of bio-based fuels or chemicals from lignocellulosic hydrolysate, inhibitory concentrations of acetic acid, released from the biomass, reduce the production rate. The undissociated form of acetic acid enters the cell by passive diffusion across the lipid bilayer, mediating toxic effects inside the cell. In order to elucidate a possible link between lipid composition and acetic acid stress, the present study presents detailed lipidomic profiling of the major lipid species found in the plasma membrane, including glycerophospholipids, sphingolipids and sterols, in Saccharomyces cerevisiae (CEN.PK 113_7D) and Zygosaccharomyces bailii (CBS7555) cultured with acetic acid. Detailed physiological characterization of the response of the two yeasts to acetic acid has also been performed in aerobic batch cultivations using bioreactors. Physiological characterization revealed, as expected, that Z. bailii is more tolerant to acetic acid than S. cerevisiae. Z. bailii grew at acetic acid concentrations above 24 g L(-1), while limited growth of S. cerevisiae was observed after 11 h when cultured with only 12 g L(-1) acetic acid. Detailed lipidomic profiling using electrospray ionization, multiple-reaction-monitoring mass spectrometry (ESI-MRM-MS) showed remarkable changes in the glycerophospholipid composition of Z. bailii, including an increase in saturated glycerophospholipids and considerable increases in complex sphingolipids in both S. cerevisiae (IPC 6.2×, MIPC 9.1×, M(IP)2C 2.2×) and Z. bailii (IPC 4.9×, MIPC 2.7×, M(IP)2C 2.7×), when cultured with acetic acid. In addition, the basal level of complex sphingolipids was significantly higher in Z. bailii than in S. cerevisiae, further emphasizing the proposed link between lipid saturation, high sphingolipid levels and acetic acid tolerance. The results also suggest that acetic acid tolerance is associated with the ability of a given strain to generate large

  13. Evaluation of non-aqueous capillary zone electrophoresis for the determination of histamine H2 receptor antagonists in pharmaceuticals.

    PubMed

    Nevado, J J Berzas; Peñalvo, G Castañeda; Dorado, R M Rodríguez

    2011-01-01

    A new non-aqueous capillary electrophoresis method is proposed for the separation and simultaneous determination of cimetidine, ranitidine, roxatidine, nizatidine and famotidine by using a 30-cm long × 75 µm i.d. fused silica capillary and UV detection at 214 nm. Using a temperature of 25°C, an applied voltage of 15 kV, and a background electrolyte consisting of methanol containing 10 mM ammonium acetate and 0.2% acetic acid allowed the analytes to be separated in less than 4 min. The limits of detection obtained ranged from 7 and 17 µg L(-1). The proposed method was successfully used to determine the analytes in pharmaceutical preparations and its results were checked against an HPLC method.

  14. Conversion to eslicarbazepine acetate monotherapy

    PubMed Central

    French, Jacqueline; Jacobson, Mercedes P.; Pazdera, Ladislav; Gough, Mallory; Cheng, Hailong; Grinnell, Todd; Blum, David

    2016-01-01

    Objective: To assess the efficacy and safety of eslicarbazepine acetate (ESL) monotherapy. Methods: This post hoc pooled analysis of 2 randomized double-blind studies (093-045 and -046) included adults with partial-onset seizures medically uncontrolled by 1 or 2 antiepileptic drugs (AEDs). Following the baseline period (8 weeks), eligible patients were randomized 2:1 to receive ESL 1,600 mg or 1,200 mg once daily for 18 weeks; the primary endpoint was study exit by meeting predefined exit criteria (signifying worsening seizure control). In each study, treatment was considered effective if the upper 95% confidence limit for exit rate was lower than the historical control threshold (65.3%). Results: Pooled exit rates were as follows: ESL 1,600 mg = 20.6% (95% confidence interval: 15.6%–26.8%); ESL 1,200 mg = 30.8% (23.0%–40.5%). Use of 2 baseline AEDs or rescue medication, US location, epilepsy duration ≥20 years, and higher maximum baseline seizure frequency were associated with higher exit risks. Median percent reductions in standardized seizure frequency between baseline and the 18-week double-blind period were as follows: ESL 1,600 mg = 43.2%; ESL 1,200 mg = 35.7%; baseline carbamazepine use was associated with smaller reductions. Safety profiles were similar between ESL doses. Conclusions: Exit rates for ESL monotherapy (1,600 mg and 1,200 mg once daily) were lower than the historical control threshold, irrespective of baseline AED use and region, with no additional safety concerns identified. Clinical factors and location clearly influence treatment responses in conversion-to-monotherapy trials. Classification of evidence: This pooled analysis provides Class IV evidence that for adults with medically uncontrolled partial-onset seizures, ESL monotherapy is well tolerated and effective. PMID:26911639

  15. Electrophoretic extraction of proteins from two-dimensional electrophoresis gel spots

    SciTech Connect

    Zhang, Jian-Shi; Giometti, C.S.; Tollaksen, S.L.

    1987-09-04

    After two-dimensional electrophoresis of proteins or the like, resulting in a polyacrylamide gel slab having a pattern of protein gel spots thereon, an individual protein gel spot is cored out from the slab, to form a gel spot core which is placed in an extraction tube, with a dialysis membrane across the lower end of the tube. Replicate gel spots can be cored out from replicate gel slabs and placed in the extraction tube. Molten agarose gel is poured into the extraction tube where the agarose gel hardens to form an immobilizing gel, covering the gel spot cores. The upper end portion of the extraction tube is filled with a volume of buffer solution, and the upper end is closed by another dialysis membrane. Upper and lower bodies of a buffer solution are brought into contact with the upper and lower membranes and are provided with electrodes connected to the positive and negative terminals of a dc power supply, thereby producing an electrical current which flows through the upper membrane, the volume of buffer solution, the agarose, the gel spot cores and the lower membrane. The current causes the proteins to be extracted electrophoretically from the gel spot cores, so that the extracted proteins accumulate and are contained in the space between the agarose gel and the upper membrane. 8 figs.

  16. The fluid mechanics of continuous flow electrophoresis

    NASA Technical Reports Server (NTRS)

    Saville, D. A.

    1990-01-01

    The overall objective is to establish theoretically and confirm experimentally the ultimate capabilities of continuous flow electrophoresis chambers operating in an environment essentially free of particle sedimentation and buoyancy. The efforts are devoted to: (1) studying the effects of particle concentration on sample conductivity and dielectric constant. The dielectric constant and conductivity were identified as playing crucial roles in the behavior of the sample and on the resolving power and throughput of continuous flow devices; and (2) improving the extant mathematical models to predict flow fields and particle trajectories in continuous flow electrophoresis. A dielectric spectrometer was designed and built to measure the complex dielectric constant of a colloidal dispersion as a function of frequency between 500 Hz and 200 kHz. The real part of the signal can be related to the sample's conductivity and the imaginary part to its dielectric constant. Measurements of the dielectric constants of several different dispersions disclosed that the dielectric constants of dilute systems of the sort encountered in particle electrophoresis are much larger than would be expected based on the extant theory. Experiments were carried out to show that, in many cases, this behavior is due to the presence of a filamentary structure of small hairs on the particle surface. A technique for producing electrokinetically ideal synthetic latex particles by heat treating was developed. Given the ubiquitous nature of hairy surfaces with both cells and synthetic particles, it was deemed necessary to develop a theory to explain their behavior. A theory for electrophoretic mobility of hairy particles was developed. Finally, the extant computer programs for predicting the structure of electro-osmotically driven flows were extended to encompass flow channels with variable wall mobilities.

  17. Hybrid slab-microchannel gel electrophoresis system

    DOEpatents

    Balch, Joseph W.; Carrano, Anthony V.; Davidson, James C.; Koo, Jackson C.

    1998-01-01

    A hybrid slab-microchannel gel electrophoresis system. The hybrid system permits the fabrication of isolated microchannels for biomolecule separations without imposing the constraint of a totally sealed system. The hybrid system is reusable and ultimately much simpler and less costly to manufacture than a closed channel plate system. The hybrid system incorporates a microslab portion of the separation medium above the microchannels, thus at least substantially reducing the possibility of non-uniform field distribution and breakdown due to uncontrollable leakage. A microslab of the sieving matrix is built into the system by using plastic spacer materials and is used to uniformly couple the top plate with the bottom microchannel plate.

  18. Capillary electrophoresis with indirect amperometric detection.

    PubMed

    Olefirowicz, T M; Ewing, A G

    1990-01-19

    The use of indirect amperometric detection with capillary electrophoresis is demonstrated. The system consists of a porous glass coupler which allows amperometric detection at a carbon fiber electrode placed in the end of the capillary. 3,4-Dihydroxybenzylamine is added to the buffer system as a continuously eluting electrophore. Indirect amperometric detection in 9-mumol I.D. capillaries provides detection limits as low as 380 attomole for the amino acid arginine. Finally, both direct and indirect amperometric detection can be accomplished simultaneously.

  19. DNA electrophoresis on a flat surface.

    PubMed

    Pernodet, N; Samuilov, V; Shin, K; Sokolov, J; Rafailovich, M H; Gersappe, D; Chu, B

    2000-12-25

    We report a new approach for performing DNA electrophoresis. Using experimental studies and molecular dynamics simulations, we show that a perfectly flat silicon wafer, without any surface features, can be used to fractionate DNA in free solution. We determine that the ability of a flat surface to separate DNA molecules results from the local friction between the surface and the adsorbed DNA segments. We control this friction by coating the Si surface with silane monolayer films and show that it is possible to systematically change the size range of DNA that can be separated.

  20. Microfabricated capillary array electrophoresis device and method

    DOEpatents

    Simpson, Peter C.; Mathies, Richard A.; Woolley, Adam T.

    2000-01-01

    A capillary array electrophoresis (CAE) micro-plate with an array of separation channels connected to an array of sample reservoirs on the plate. The sample reservoirs are organized into one or more sample injectors. One or more waste reservoirs are provided to collect wastes from reservoirs in each of the sample injectors. Additionally, a cathode reservoir is also multiplexed with one or more separation channels. To complete the electrical path, an anode reservoir which is common to some or all separation channels is also provided on the micro-plate. Moreover, the channel layout keeps the distance from the anode to each of the cathodes approximately constant.

  1. Microfabricated capillary array electrophoresis device and method

    DOEpatents

    Simpson, Peter C.; Mathies, Richard A.; Woolley, Adam T.

    2004-06-15

    A capillary array electrophoresis (CAE) micro-plate with an array of separation channels connected to an array of sample reservoirs on the plate. The sample reservoirs are organized into one or more sample injectors. One or more waste reservoirs are provided to collect wastes from reservoirs in each of the sample injectors. Additionally, a cathode reservoir is also multiplexed with one or more separation channels. To complete the electrical path, an anode reservoir which is common to some or all separation channels is also provided on the micro-plate. Moreover, the channel layout keeps the distance from the anode to each of the cathodes approximately constant.

  2. Electrohydrodynamic effects in continuous flow electrophoresis

    NASA Technical Reports Server (NTRS)

    Rhodes, P. H.; Snyder, R. S.; Roberts, G. O.; Baygents, J. C.

    1991-01-01

    We demonstrate experimentally and theoretically the importance of electrohydrodynamic (EHD) flows in continuous-flow electrophoresis (CFE) separations. These flows are associated with variations in the conductivity or dielectric constant, and are quadratic in the field strength. They appear to be the main cause of extraneous and undesired flows in CFE which have degraded separation performance and have until now not been explained. We discuss the importance of EHD flows relative to other effects. We also describe possible techniques for reducing the associated degradation of CFE separations.

  3. Detection of connexins in liver cells using sodiumdodecylsulfate polyacrylamide gel electrophoresis and immunoblot analysis

    PubMed Central

    Willebrords, Joost; Maes, Michaël; Yanguas, Sara Crespo; Cogliati, Bruno; Vinken, Mathieu

    2016-01-01

    Summary Since connexin expression is partly regulated at the protein level, immunoblot analysis represents a frequently addressed technique in the connexin research field. The present chapter describes the set-up of an immunoblot procedure, including protein extraction and quantification from biological samples, gel electrophoresis, protein transfer and immunoblotting, which is optimized for analysis of connexins in liver tissue. In essence, proteins are separated on a polyacrylamide gel using sodiumdodecylsulfate followed by transfer of proteins on a nitrocellulose membrane. The latter allows specific detection of connexins with antibodies combined with revelation through enhanced chemiluminescence. PMID:27207285

  4. Recent advances in amino acid analysis by capillary electrophoresis.

    PubMed

    Poinsot, Véréna; Carpéné, Marie-Anne; Bouajila, Jalloul; Gavard, Pierre; Feurer, Bernard; Couderc, François

    2012-01-01

    This paper describes the most important articles that have been published on amino acid analysis using CE during the period from June 2009 to May 2011 and follows the format of the previous articles of Smith (Electrophoresis 1999, 20, 3078-3083), Prata et al. (Electrophoresis 2001, 22, 4129-4138) and Poinsot et al. (Electrophoresis 2003, 24, 4047-4062; Electrophoresis 2006, 27, 176-194; Electrophoresis 2008, 29, 207-223; Electrophoresis 2010, 31, 105-121). We present new developments in amino acid analysis with CE, which are reported describing the use of lasers or light emitting diodes for fluorescence detection, conductimetry electrochemiluminescence detectors, mass spectrometry applications, and lab-on-a-chip applications using CE. In addition, we describe articles concerning clinical studies and neurochemical applications of these techniques.

  5. Fragrance material review on 4-methylbenzyl acetate.

    PubMed

    McGinty, D; Letizia, C S; Api, A M

    2012-09-01

    A toxicologic and dermatologic review of 4-methylbenzyl acetate when used as a fragrance ingredient is presented. 4-Methylbenzyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 4-methylbenzyl acetate were evaluated, then summarized, and includes: physical properties, skin irritation, skin sensitization, and elicitation data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances.

  6. [Microchip capillary electrophoresis-electrochemical detection of nitrite using a modified carbon paste electrode].

    PubMed

    Wei, Peihai; Li, Guanbin; Chen, Liren

    2005-05-01

    Carbon paste electrode modified with 3-mercaptopropyltrimethoxysilane copper (MPTMS-Cu) encapsulated in molecular sieve MCM-41 was prepared. The electrocatalytic behavior of the modified electrode towards the reduction of nitrite was studied in detail, including pH-dependence and composition-dependence studies. A microchip capillary electrophoresis-electrochemical detection system with the modified carbon paste as electrode was fabricated. The application of the system for the detection of nitrite is discussed. The detection was finished within 40 s under the following conditions: 50 mmol/L sodium acetate buffer at pH 5.8, -1.6 kV running voltage. The peak current was linear with the concentration of nitrite over 10.0 micromol/L-5.0 mmol/L and the detection limit was 4.0 micromol/L in pure water.

  7. The lifespan-promoting effect of acetic acid and Reishi polysaccharide.

    PubMed

    Chuang, Ming-Hong; Chiou, Shyh-Horng; Huang, Chun-Hao; Yang, Wen-Bin; Wong, Chi-Huey

    2009-11-15

    Using Caenorhabditis elegans as a model organism, various natural substances and commercial health-food supplements were screened to evaluate their effects on longevity. Among the substances tested, acetic acid and Reishi polysaccharide fraction 3 (RF3) were shown to increase the expression of the lifespan and longevity-related transcription factor DAF-16 in C. elegans. We have shown that RF3 activates DAF-16 expression via TIR-1 receptor and MAPK pathway whereas acetic acid inhibits the trans-membrane receptor DAF-2 of the insulin/IGF-1 pathway to indirectly activate DAF-16 expression. In addition, a mixture of acetic acid and RF3 possesses a combined effect 30-40% greater than either substance used alone. A proteomic analysis of C. elegans using 2-DE and LC-MS/MS was then carried out, and 15 differentially expressed proteins involved in the lifespan-promoting activity were identified.

  8. Acetic acid induces a programmed cell death process in the food spoilage yeast Zygosaccharomyces bailii.

    PubMed

    Ludovico, Paula; Sansonetty, Filipe; Silva, Manuel T; Côrte-Real, Manuela

    2003-03-01

    Here we show that 320-800 mM acetic acid induces in Zygosaccharomyces bailii a programmed cell death (PCD) process that is inhibited by cycloheximide, is accompanied by structural and biochemical alterations typical of apoptosis, and occurs in cells with preserved mitochondrial and plasma membrane integrity (as revealed by rhodamine 123 (Rh123) and propidium iodide (PI) staining, respectively). Mitochondrial ultrastructural changes, namely decrease of the cristae number, formation of myelinic bodies and swelling were also seen. Exposure to acetic acid above 800 mM resulted in killing by necrosis. The occurrence of an acetic acid-induced active cell death process in Z. bailii reinforces the concept of a physiological role of the PCD in the normal yeast life cycle.

  9. Chloroplast membranes of the green alga Acetabularia mediterranea. II. Topography of the chloroplast membrane.

    PubMed

    Apel, K; Miller, K R; Bogorad, L; Miller, G J

    1976-12-01

    The localization of the chlorophyll-protein complexes inside the thylakoid membrane of Acetabularia mediterranea was determined by fractionating the chloroplast membrane with EDTA and Triton X-100, by using pronase treatment, and by labeling the surface-exposed proteins with 125I. The effects of the various treatments were established by electrophoresis of the solubilized membrane fractions and electron microscopy. After EDTA and pronase treatment, the membrane structure was still intact. Only the two chlorophyll-protein complexes of 67,000 and 152,000 daltons and an additional polypeptides were found in the membrane before the EDTA and pronase treatment. The 125,000 dalton complex seems to be buried inside the lipid layer. The 23,000 dalton subunit of the 67,000 dalton complex is largely exposed to the surface of the EDTA-insoluble membrane and only the chlorophyll-binding subunit of 21,500 daltons is buried inside the lipid layer.

  10. [Experimental study of proflavine acetate phototransformation processes].

    PubMed

    Zholdakova, Z I; Sinitsyna, O O; Lebedev, A T; Kharchevnikova, N V

    2009-01-01

    Changes in proflavine acetate phototransformation processes upon exposure to visible-range irradiation were studied by high performance liquid chromatography. Proflavine acetate was offered as a photosensitizer during photodynamic water disinfection. Dye transformation products upon time-varying exposure to irradiation were identified. By using structure-activity relationships and information from toxicity databases, the authors evaluated the hazard of the identified products and identified the most hazardous ones.

  11. Thermal lens detector system for capillary electrophoresis

    NASA Astrophysics Data System (ADS)

    Seidel, Bernd S.; Faubel, Werner N.; Ache, Hans-Joachim

    1997-07-01

    The characteristics and the performance of a thermal lens detector, which uses a double-beam absorption scheme, were studied in a capillary electrophoresis system with various types of toxic pollutants, e.g., pesticides. The setup of the detector system was miniaturized using the smallest diverging path lengths between the cell and the pinhole (4 mm). The probe laser beam (He:Ne laser, 633 nm) and the excitation beam (Ar+ ion laser, 364, 457, 488, and 514 nm) with a crossed setup were directed by mirrors into two microscope objectives that focused the beam to a 5-micrometers waist inside the capillary. The detection volume was on the order of 75 nl when a 75-micrometers capillary was employed. The change in intensity of the probe beam was detected by a photodiode behind a pinhole, which was protected with different band-pass interference filters. The excitation laser can be used in the multiline order. Micellar electrokinetic methods are used for pesticide separation. The performance of the detector in capillary electrophoresis was assessed with various types of capillaries and compared with a conventional absorption detector. The limit of detection is at least one order of magnitude better than it is with the absorption detector.

  12. Micro-injector for capillary electrophoresis.

    PubMed

    Sáiz, Jorge; Koenka, Israel Joel; García-Ruiz, Carmen; Müller, Beat; Chwalek, Thomas; Hauser, Peter C

    2015-08-01

    A novel micro-injector for capillary electrophoresis for the handling of samples with volumes down to as little as 300 nL was designed and built in our laboratory for analyses in which the available volume is a limitation. The sample is placed into a small cavity located directly in front of the separation capillary, and the injection is then carried out automatically by controlled pressurization of the chamber with compressed air. The system also allows automated flushing of the injection chamber as well as of the capillary. In a trial with a capillary electrophoresis system with contactless conductivity detector, employing a capillary of 25 μm diameter, the results showed good stability of migration times and peak areas. To illustrate the technique, the fast separation of five inorganic cations (Na(+) , K(+) , NH4 (+) , Ca(2+) , and Mg(2+) ) was set up. This could be achieved in less than 3 min, with good limits of detection (10 μM) and linear ranges (between about 10 and 1000 μM). The system was demonstrated for the determination of the inorganic cations in porewater samples of a lake sediment core.

  13. Fractionation of mineral species by electrophoresis

    NASA Technical Reports Server (NTRS)

    Dunning, J. D.; Herren, B. J.; Tipps, R. W.; Snyder, R. S.

    1982-01-01

    The fractionation of fine-grained aggregates into their major components is a problem in many scientific areas including earth and planetary science. Electrophoresis, the transport of electrically charged particles, immersed in a suspension medium, by a direct current field (Bier, 1959), was employed in this study as a means of separating simulated lunar soil into its constituent minerals. In these tests, conducted in a static analytical cylindrical microelectrophoresis apparatus, samples of simulated lunar soil and samples of pure mineral constituents were placed in the chamber; the electrophoretic mobilities of the lunar soil and the individual mineral constituents were measured. In most of the suspension buffers employed separability was indicated, on the basis of differences in mobility, for all the constituent mineral species except ilmenite and pyroxene, which were not efficiently separable in any of the buffers. Although only a few suspension media were employed, the success of this initial study suggests that electrophoresis may be an important mineral fractionation option in fine-grained aggregate processing.

  14. Gel Electrophoresis of Gold-DNA Nanoconjugates

    DOE PAGES

    Pellegrino, T.; Sperling, R. A.; Alivisatos, A. P.; ...

    2007-01-01

    Gold-DNA conjugates were investigated in detail by a comprehensive gel electrophoresis study based on 1200 gels. A controlled number of single-stranded DNA of different length was attached specifically via thiol-Au bonds to phosphine-stabilized colloidal gold nanoparticles. Alternatively, the surface of the gold particles was saturated with single stranded DNA of different length either specifically via thiol-Au bonds or by nonspecific adsorption. From the experimentally determined electrophoretic mobilities, estimates for the effective diameters of the gold-DNA conjugates were derived by applying two different data treatment approaches. The first method is based on making a calibration curve for the relation between effectivemore » diameters and mobilities with gold nanoparticles of known diameter. The second method is based on Ferguson analysis which uses gold nanoparticles of known diameter as reference database. Our study shows that effective diameters derived from gel electrophoresis measurements are affected with a high error bar as the determined values strongly depend on the method of evaluation, though relative changes in size upon binding of molecules can be detected with high precision. Furthermore, in this study, the specific attachment of DNA via gold-thiol bonds to Au nanoparticles is compared to nonspecific adsorption of DNA. Also, the maximum number of DNA molecules that can be bound per particle was determined.« less

  15. Higher sensitivity of capillary electrophoresis in detecting hemoglobin A2'compared to traditional gel electrophoresis.

    PubMed

    Oleske, Deanna Alicia; Huang, Richard Sheng Poe; Dasgupta, Amitava; Nguyen, Andy; Wahed, Amer

    2014-01-01

    HbA2' (also called Hb B2) is the most common delta-globin chain defect and is reported to occur in 1-2% of the African American population. The major clinical significance of HbA2' is that the failure to detect it might lead to an underestimation of the total HbA2, leading to failure to diagnose β-thalassemia minor. In order to diagnose β-thalassemia minor, both HbA2 and HbA2' levels must be combined.Hb A2' accounts for a small percentage (1-2%) of the total hemoglobin in heterozygotes. It is difficult to detect this small amount by traditional gel electrophoresis. Using HPLC Hb A2' is easily detected as it produces a minor peak in the S window. Other conditions which might interfere with detection of HbA2' by HPLC include Hb S trait or Hb SS disease (Hb A2' hidden in the S peak), transfused Hb SS (Hb S peak may be very small), Hb C trait or Hb CC disease (glycosylated Hb C elutes in the S window), and Hb G (Hb G2 elutes in the S window). All of the above conditions, including Hb A2', occur most commonly in the same ethnic group (African American). We reviewed 654 consecutive cases over a period of three months for the presence of Hb A2' in our laboratory where capillary electrophoresis is used as the primary diagnostic tool. We detected seven cases (1.07 %) of HbA2'. In contrast, we did not detect any HbA2' using conventional gel electrophoresis in the last one year (2,580 cases). Although in none of the seven cases the sum of Hb A2 and Hb A2' exceeded 3.5%, we believe that capillary electrophoresis allows for a better detection of Hb A2' than gel electrophoresis and HPLC.

  16. Pervaporation as interface between solid samples and capillary electrophoresis. Determination of biogenic amines in food.

    PubMed

    Ruiz-Jiménez, J; Luque de Castro, M D

    2006-03-31

    A fully automated system for solid sample analysis has been developed by on-line coupling a pervaporation module with a capillary electrophoresis system using as interface a flow injection manifold and a modified capillary electrophoresis vial. The pervaporator allows leaching, formation of the volatile analytes and their removal by evaporation and diffusion through a membrane. The isolated analytes are on-line injected into the capillary electrophoresis system meanwhile the solid matrix remains in the pervaporator. By this approach biogenic amines have been determined in fish, meat and sausage. The detection limits (LOD) ranged between 0.2 and 0.6microg/ml, the quantification limits between 0.7 and 1.9microg/ml and the linear dynamic between 0.4 and 400microg/ml. The precision, expressed as relative standard deviation (RSD), ranged between 0.76 and 4.21% for repeatability and between 1.12 and 4.78% for within laboratory reproducibility. The errors, expressed as RSD for all compounds, ranged between 1.64 and 3.42%. The optimal pervaporation time and that necessary for the individual separation/detection of the target analytes are 14 and 12min, respectively. The analysis frequency is higher than 3h(-1) and the sample size 0.1g. A two-tailed t-test, used to compare the proposed method with that based on HPLC, yielded similar results for nine different samples.

  17. Specific labeling and partial inactivation of cytochrome oxidase by fluorescein mercuric acetate.

    PubMed

    Stonehuerner, J; O'Brien, P; Kendrick, L; Hall, J; Millett, F

    1985-09-25

    Addition of 1 eq of fluorescein mercuric acetate (FMA) to beef heart cytochrome oxidase was found to inhibit the steady-state electron transfer activity by 50%, but further additions up to 10 eq had no additional effect on activity. The partial inhibition caused by FMA is thus similar to that observed with other mercury compounds (Mann, A. J., and Auer, H. E. (1980) J. Biol. Chem. 255, 454-458). The fluorescence of FMA was quenched by a factor of 10 upon binding to cytochrome oxidase, consistent with the involvement of a sulfhydryl group. However, addition of mercuric chloride to FMA-cytochrome oxidase resulted in an increase in fluorescence, suggesting that FMA was displaced from the high affinity binding site. Cytochrome c binding to FMA-cytochrome oxidase resulted in a 10% decrease in the fluorescence, possibly caused by Forster energy transfer from FMA to the cytochrome c heme. The binding site for FMA in cytochrome oxidase was investigated by carrying out sodium dodecyl sulfate gel electrophoresis under progressively milder dissociation conditions. When FMA-cytochrome oxidase was dissociated with 3% sodium dodecyl sulfate and 6 M urea, FMA was predominantly bound to subunit II following electrophoresis. However, when the dissociation was carried out at 4 degrees C in the absence of urea with progressively smaller amounts of lithium dodecyl sulfate, the labeling of subunit II decreased and that of subunit I increased. These experiments demonstrate that mercury compounds bind to a high affinity site on cytochrome oxidase, possibly located in subunit I, but then migrate to subunit II under the normal sodium dodecyl sulfate gel electrophoresis conditions. A definitive assignment of the high affinity binding site in the native enzyme cannot be made, however, because it is possible that mercury compounds can migrate from one sulfhydryl to another under even the mildest electrophoresis conditions.

  18. A biologically inspired hydrophobic membrane for application in pervaporation.

    PubMed

    Jullok, Nora; Martínez, Rodrigo; Wouters, Christine; Luis, Patricia; Sanz, María Teresa; Van der Bruggen, Bart

    2013-02-05

    An artificial polydimethylsiloxane/polyphenylsulfone (PDMS/PPSU) membrane, which emulates the hydrophobic behavior of natural membranes, was synthesized. Hydrophobicity was achieved by coating the membrane surface sublayer using conventional silicon material, which imitates the character of epicuticular wax (EW) of Prunus laurocerasus L. leaves. It was then applied as a separation medium in pervaporation (PV) of diluted mixtures of ethyl acetate and aroma compounds. The membrane's biomimetic characteristics were evaluated using surface morphology analyses, that is, Fourier transform infrared (FTIR), water contact angle measurements, and SEM imaging. A comparison of properties of the membranes synthesized in this work against selected hydrophobic plant leaves indicated a good agreement. PV using these biologically inspired artificial membranes demonstrated preference for the permeation of ethyl acetate. Besides intrinsic characteristics, it was also observed that the chemical potential is highly influential in activating sorption, diffusion, and desorption of a specific compound.

  19. Indium acetate toxicity in male reproductive system in rats.

    PubMed

    Lee, Kuo-Hsin; Chen, Hsiu-Ling; Leung, Chung-Man; Chen, Hsin-Pao; Hsu, Ping-Chi

    2016-01-01

    Indium, a rare earth metal characterized by high plasticity, corrosion resistance, and a low melting point, is widely used in the electronics industry, but has been reported to be an environmental pollutant and a health hazard. We designed a study to investigate the effects of subacute exposure of indium compounds on male reproductive function. Twelve-week old male Sprague-Dawley rats were randomly divided into test and control groups, and received weekly intraperitoneal injections of indium acetate (1.5 mg/kg body weight) and normal saline, respectively, for 8 weeks. Serum indium levels, cauda epididymal sperm count, motility, morphology, chromatin DNA structure, mitochondrial membrane potential, oxidative stress, and testis DNA content were investigated. The indium acetate-treated group showed significant reproductive toxicity, as well as an increased percentage of sperm morphology abnormality, chromatin integrity damage, and superoxide anion generation. Furthermore, positive correlations among sperm morphology abnormalities, chromatin DNA damage, and superoxide anion generation were also noted. The results of this study demonstrated the toxic effect of subacute low-dose indium exposure during the period of sexual maturation on male reproductive function in adulthood, through an increase in oxidative stress and sperm chromatin DNA damage during spermiogenesis, in a rodent model.

  20. Covalent interaction of chloroacetic and acetic acids with cholesterol.

    PubMed

    Bhat, H K; Ansari, G A

    1989-01-01

    The covalent interaction of chloroacetic acid with rat liver lipids was studied in vivo. Rats were given a single oral dose (8.75 mg/kg, 50 microCi) of 1-[14C]chloroacetic acid and sacrificed after 24 hours. Lipids extracted from the livers were separated into neutral lipids and phospholipids by solid-phase extraction using sep-pak silica cartridges. The neutral lipid fraction was further fractionated by preparative thin-layer chromatography followed by reverse-phase high-performance liquid chromatography. The fraction corresponding to the retention time of standard cholesteryl chloroacetate gave a pseudomolecular ion peak at m/z 480/482 ratio: (3:1) on ammonia chemical ionization mass spectrometry, and the fragmentation pattern was found to be similar to that of the standard sample. Under similar conditions, acetic acid resulted in the formation of cholesteryl acetate. The effect of such conjugation reactions on the cell membrane and their contribution to toxicity is presently unknown.

  1. Determination of herbicides paraquat, glyphosate, and aminomethylphosphonic acid in marijuana samples by capillary electrophoresis.

    PubMed

    Lanaro, Rafael; Costa, José L; Cazenave, Silvia O S; Zanolli-Filho, Luiz A; Tavares, Marina F M; Chasin, Alice A M

    2015-01-01

    In this work, two methods were developed to determine herbicides paraquat, glyphosate, and aminomethylphosphonic acid (AMPA) in marijuana samples by capillary electrophoresis. For paraquat analysis, sample was extracted with aqueous acetic acid solution and analyzed by capillary zone electrophoresis with direct UV detection. The running electrolyte was 50 mmol/L phosphate buffer (pH 2.50). For glyphosate and AMPA, indirect UV/VIS detection was used, as these substances do not present chromophoric groups. Samples were extracted with 5 mmol/L hydrochloric acid. The running electrolyte was 10 mmol/L gallic acid, 6 mmol/L TRIS, and 0.1 mmol/L CTAB (pH = 4.7). The methods presented good linearity, precision, accuracy, and recovery. Paraquat was detected in 12 samples (n = 130), ranging from 0.01 to 25.1 mg/g. Three samples were positive for glyphosate (0.15-0.75 mg/g), and one sample presented AMPA as well. Experimental studies are suggested to evaluate the risks of these concentrations to marijuana user.

  2. Cytoplasmic polyhedrosis virus classification by electropherotype; validation by serological analyses and agarose gel electrophoresis.

    PubMed

    Mertens, P P; Crook, N E; Rubinstein, R; Pedley, S; Payne, C C

    1989-01-01

    Serological analyses of several different cytoplasmic polyhedrosis viruses (CPVs), including two type 1 CPVs from Bombyx mori, type 1 CPV from Dendrolimus spectabilis, type 12 CPV from Autographa gamma, type 2 CPV from Inachis io, type 5 CPV from Orgyia pseudotsugata and type 5 CPV from Heliothis armigera, demonstrated a close correlation between the antigenic properties of the polyhedrin or virus particle structural proteins and the genomic dsRNA electropherotypes. The dsRNAs of these viruses were analysed by electrophoresis in 3% and 10% polyacrylamide gels with a discontinuous Tris-HCl/Tris-glycine buffer system or by 1% agarose gel electrophoresis using a continuous Tris-acetate-EDTA buffer system. Electrophoretic analysis in agarose gels was found to be the most suitable for the classification of CPV isolates into electropherotypes, and the results obtained showed a close correlation with the observed antigenic relationships between different virus isolates. However, electrophoretic analysis in 10% polyacrylamide gels was most sensitive for the detection of intra-type variation and the presence of mixed virus isolates.

  3. Separation and characterization of barley (Hordeum vulgare L.) hordeins by free zone capillary electrophoresis.

    PubMed

    Lookhart, G L; Bean, S R; Jones, B L

    1999-06-01

    Extraction conditions, separation conditions, and capillary rinsing protocols were optimized for the separation of barley hordeins by free zone capillary electrophoresis. Stable hordein extracts were obtained with a single 5 min extraction after the albumins and globulins were removed. Hordeins had to be reduced for optimal resolution. Optimum separation conditions for hordein separations were 100 mM phosphate-glycine buffer containing 20% acetonitrile and 0.05% hydroxypropylmethylcellulose. The addition of zwitterionic sulfobetaine detergents containing hydrocarbon tails of eight and ten carbons slightly improved the resolution of the separations, but not enough to warrant their use on a routine basis. The migration positions of the hordein subclasses were determined by two- dimensional reversed-phase high-performance liquid chromatography x free zone capillary electrophoresis mapping. The hordein subclasses formed clusters similar to those of wheat gliadins. Separation-to-separation repeatability was good, with migration time relative standard deviations < 1% for a 15-run period. For routine discrimination of cultivars, a 2 min post-separation rinse with 500 mM acetic acid was necessary to prevent protein build-up on the capillary walls. An example of successfully differentiating barley cultivars using this technique is shown.

  4. Distinct effects of sorbic acid and acetic acid on the electrophysiology and metabolism of Bacillus subtilis.

    PubMed

    van Beilen, J W A; Teixeira de Mattos, M J; Hellingwerf, K J; Brul, S

    2014-10-01

    Sorbic acid and acetic acid are among the weak organic acid preservatives most commonly used to improve the microbiological stability of foods. They have similar pKa values, but sorbic acid is a far more potent preservative. Weak organic acids are most effective at low pH. Under these circumstances, they are assumed to diffuse across the membrane as neutral undissociated acids. We show here that the level of initial intracellular acidification depends on the concentration of undissociated acid and less on the nature of the acid. Recovery of the internal pH depends on the presence of an energy source, but acidification of the cytosol causes a decrease in glucose flux. Furthermore, sorbic acid is a more potent uncoupler of the membrane potential than acetic acid. Together these effects may also slow the rate of ATP synthesis significantly and may thus (partially) explain sorbic acid's effectiveness.

  5. Study on structure and hydrophobicity of PP/EVA co-blending membrane: Quenching rate

    NASA Astrophysics Data System (ADS)

    Tang, Na; Li, Zhao; Hua, Xinxin

    2017-03-01

    Isotactic polypropylene (iPP)/ethylene vinyl acetate (EVA) co-blending hydrophobic microporous membranes for vacuum membrane distillation (VMD) were prepared via thermally induced phase separation (TIPS). In the process of preparation, quenching rate has a great influence on the membrane morphology.

  6. A centrifugal method for the evaluation of polymer membranes for reverse osmosis

    NASA Technical Reports Server (NTRS)

    Hollahan, J. R.; Wydeven, T.; Mccullough, R. P.

    1973-01-01

    A rapid and simple method employing the laboratory centrifuge shows promise for evaluation of membrane performance during reverse osmosis. Results are presented for cellulose acetate membranes for rejection of salt and urea dissolved solids. Implications of the study are to rapid screening of membrane performance, use in laboratories with limited facilities, and possible space waste water purification.

  7. Doped with Sodium Acetate and Metallic Sodium

    NASA Astrophysics Data System (ADS)

    Tada, Satoki; Isoda, Yukihiro; Udono, Haruhiko; Fujiu, Hirofumi; Kumagai, Shunji; Shinohara, Yoshikazu

    2014-06-01

    We have investigated the thermoelectric properties of p-type Na-doped Mg2 Si0.25Sn0.75 solid solutions prepared by liquid-solid reaction and hot-pressing methods. Na was introduced into Mg2Si0.25Sn0.75 by using either sodium acetate (CH3COONa) or metallic sodium (2 N). The samples doped with sodium acetate consisted of phases with antifluorite structure and a small amount of MgO as revealed by x-ray diffraction, whereas the sample doped with metallic sodium contained the Sn, MgO, and Mg2SiSn phases. The hole concentrations of Mg1.975Na0.025Si0.25Sn0.75 doped by sodium acetate and metallic sodium were 1.84 × 1025 m-3 and 1.22 × 1025 m-3, respectively, resulting in resistivities of 4.96 × 10-5 Ω m (sodium acetate) and 1.09 × 10-5 Ω m (metallic sodium). The Seebeck coefficients were 198 μV K-1 (sodium acetate) and 241 μV K-1 (metallic sodium). The figures of merit for Mg1.975Na0.025Si0.25Sn0.75 were 0.40 × 10-3 K-1 (sodium acetate) and 0.25 × 10-3 K-1 (metallic sodium) at 400 K. Thus, sodium acetate is a suitable Na dopant for Mg2Si1- x Sn x .

  8. Expression and function of membrane regulators of complement on rat astrocytes in culture.

    PubMed Central

    Rogers, C A; Gasque, P; Piddlesden, S J; Okada, N; Holers, V M; Morgan, B P

    1996-01-01

    Human astrocytes express CD59, decay accelerating factor and membrane cofactor protein to restrict the damaging effect of complement (C) activation on their cell surface. 5I2 antigen (5I2 Ag) is the functional analogue of the latter two proteins in rats. We here demonstrate the surface expression on rat astrocytes of CD59 and 5I2 Ag and use sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blotting to confirm their identity and to quantify expression. Rat CD59 (MW 20,000) was expressed at 720 x 10(3) molecules per cell and 5I2 Ag (MW 58,000 and 64,000) at 625 x 10(3) molecules per cell. Reverse transcription-polymerase chain reaction using specific oligonucleotide primers demonstrated expression of mRNA for each protein. Twenty-four-hour stimulation with inflammatory cytokines (interferon-gamma, tumour necrosis factor-alpha, interleukins-1 beta, -2 and -6) or phorbol myristate acetate had no significant effect on the level of expression of either protein as determined by Western blotting. Lysis caused by classical pathway activation of C in human or rat serum was enhanced by blocking the function of CD59 and 5I2 Ag on rat astrocytes with monoclonal antibodies. Images Figure 2 Figure 3 Figure 4 PMID:8707343

  9. Polycation binding to glomerular basement membrane. Effect of biochemical modification.

    PubMed

    Bertolatus, J A; Hunsicker, L G

    1987-02-01

    The polycation hexadimethrine (HDM) binds to anionic sites in the glomerular basement membrane (GBM) and causes heavy proteinuria when infused in vivo. An in vitro assay of 3H-HDM binding to isolated dog GBM was developed, to permit further analysis of the GBM components binding HDM. 3H-HDM binding to isolated GBM was saturable, reversible in dose-dependent fashion by competing polycations, and inhibited by increasing salt concentration and low pH. The pH dependence of binding suggested that most of the HDM binds to carboxyl groups rather than to the sulfate groups of proteoglycans. Removal of heparan sulfate by heparinase or purified heparatinase had no detectable effect on HDM binding. Treatment of GBM with neuraminidase, hyaluronidase, or chondroitinase reduced binding of HDM by a maximum of 20 to 38%. However, substitution of carboxyl anions with nonionizable glycine methyl ester residues resulted in complete elimination of HDM binding. Parallel results were obtained in studies of glomerular localization of cationized ferritin (CatF), pI 8.5. After carboxyl substitution, GBM did not bind CatF; heparinase-treated GBM bound CatF in a distribution not demonstrably different from normal. Cellulose acetate electrophoresis of glycosaminoglycan fractions prepared from treated GBM confirmed that carboxyl modification did not alter the content or charge of the heparan sulfate of GBM, but heparinase treatment removed at least 90% of heparan sulfate. The results indicate that carboxyl groups are quantitatively more important than heparan sulfate for binding of HDM in vitro. Since HDM causes proteinuria in vivo, carboxyl groups may be important for maintenance of normal permselectivity.

  10. Biocompatibility aspects of cellophane, cellulose acetate, polyacrylonitrile, polysulfone and polycarbonate hemodialyzers.

    PubMed

    Smeby, L C; Widerøe, T E; Balstad, T; Jørstad, S

    1986-01-01

    The biocompatibility of cuprammonium rayon (Cu), cellulose acetate, polysulfone (Ps) and polyacrylonitrile hollow-fiber dialyzers and a polycarbonate-polyether flat plate dialyzer has been investigated. The Cu dialyzer resulted in more complement activation and a greater degree of leukopenia than the others, while the Ps hollow-fiber dialyzer appeared to be the most biocompatible of the membrane equipment in this study. These results were confirmed by in vitro evaluations and microscopic examinations of the different dialyzers.

  11. Chip electrophoresis of gelatin-based nanoparticles.

    PubMed

    Weiss, Victor U; Lehner, Angela; Grombe, Ringo; Marchetti-Deschmann, Martina; Allmaier, Günter

    2013-08-01

    Recently, biodegradable nanoparticles received increasing attention for pharmaceutical applications as well as applications in the food industry. With the current investigation we demonstrate chip electrophoresis of fluorescently (FL) labeled gelatin nanoparticles (gelatin NPs) on a commercially available instrument. FL labeling included a step for the removal of low molecular mass material (especially excess dye molecules). Nevertheless, for the investigated gelatin NP preparation two analyte peaks, one very homogeneous with an electrophoretic net mobility of μ = -24.6 ± 0.3 × 10(-9) m(2) /Vs at the peak apex (n = 17) and another more heterogeneous peak with μ between approximately -27.2 ± 0.2 × 10(-9) m(2) /Vs and -36.6 ± 0.2 × 10(-9) m(2) /Vs at the peak beginning and end point (n = 11, respectively) were recorded. Filtration allowed enrichment of particles in the size range of approximately 35 nm (pore size employed for concentration of gelatin NPs) to 200 nm (pore size employed during FL labeling). This corresponded to the very homogeneous peak linking it to gelatin NPs, whereas the more heterogeneous peak probably corresponds to gelatin not cross-linked to such a high degree (NP building blocks). Several further gelatin NP preparations were analyzed according to the same protocol yielding peaks with electrophoretic net mobilities between -23.3 ± 0.3 × 10(-9) m(2) /Vs and -28.9 ± 0.2 × 10(-9) m(2) /Vs at peak apexes (n = 15 and 6). Chip electrophoresis allows analyte separation in less than two minutes (including electrophoretic sample injection). Together with the high sensitivity of the FL detection - the LOD as derived for the first main peak of the applied dye from the threefold standard deviation of the background noise values 80 pM for determined separation conditions - this leads to a very promising high throughput separation technique especially for the analysis of bionanoparticles. For gelatin NP preparations, chip electrophoresis

  12. A microchannel electrophoresis DNA sequencing system

    SciTech Connect

    Madabhushi, R S; Warth, T; Balch, J W; Bass, M; Brewer, L R; Copeland, A C; Davidson, J C; Fitch, J P; Kegelmeyer, L M; Kimbrough, J R; McCready, P; Nelson, D; Pastrone, R L; Richardson, P M; Swierkowski, S P; Tarte, L A; Vainer, M

    1999-01-01

    In order to increase the DNA sequencing throughput of the Joint Genome Institute, we have developed a microchannel electrophoresis system. The critical new and unique elements of this system include 1) a process for the production of arrays of 96 and 384 microchannels on bonded glass substrates up to 14 x 58 cm and 2) new sieving media for high resolution and high speed separations. With custom fabrication apparatus, microchannels are etched in a borosilicate substrate, and then fusion bonded to a top substrate 1.1 mm thick that has access holes formed in it. SEM examination shows a typical microchannel to be 40 micrometers deep x 180 micrometers wide by 46 cm long. This technology offers significant advantages over discrete capillaries or conventional slab-gel approaches. High throughput DNA sequencing with over 550 base pairs resolution has been achieved in roughly half the time of conventional sequencers. In February 1999, we begin a pre-production evaluation protocol for the microchannel and for three glass capillary electrophoresis systems (two from industry and one developed by Lawrence Berkeley National Laboratory for the Joint Genome Institute). In order to utilize these instruments for DNA production sequencing, we have been evaluating and implementing software to convert raw electropherograms into called DNA bases with an associated probability of error. Our original intent was to utilize the DNA base calling software known as Plan and Phred developed by the University of Washington. This software has been outstanding for our slab gel electrophoresis systems currently in the production facility. In our tests and evaluations of this software applied to microchannel data, we observed that the electropherograms are of a different statistical and underlying signal structure compared to slab gels. Even with substantial modifications to the software, base calling performance was not satisfactory for the microchannel data. In this paper, we will present o The

  13. Membrane extraction for detoxification of biomass hydrolysates.

    PubMed

    Grzenia, David L; Schell, Daniel J; Wickramasinghe, S Ranil

    2012-05-01

    Membrane extraction was used for the removal of sulfuric acid, acetic acid, 5-hydroxymethyl furfural and furfural from corn stover hydrolyzed with dilute sulfuric acid. Microporous polypropylene hollow fiber membranes were used. The organic extractant consisted of 15% Alamine 336 in: octanol, a 50:50 mixture of oleyl alcohol:octanol or oleyl alcohol. Rapid removal of sulfuric acid, 5-hydroxymethyl and furfural was observed. The rate of acetic acid removal decreased as the pH of the hydrolysate increased. Regeneration of the organic extractant was achieved by back extraction into an aqueous phase containing NaOH and ethanol. A cleaning protocol consisting of flushing the hydrolysate compartment with NaOH and the organic phase compartment with pure organic phase enabled regeneration and reuse of the module. Ethanol yields from hydrolysates detoxified by membrane extraction using 15% Alamine 336 in oleyl alcohol were about 10% higher than those from hydrolysates detoxified using ammonium hydroxide treatment.

  14. Membrane Extraction for Detoxification of Biomass Hydrolysates

    SciTech Connect

    Grzenia, D. L.; Schell, D. J.; Wickramasinghe, S. R.

    2012-05-01

    Membrane extraction was used for the removal of sulfuric acid, acetic acid, 5-hydroxymethyl furfural and furfural from corn stover hydrolyzed with dilute sulfuric acid. Microporous polypropylene hollow fiber membranes were used. The organic extractant consisted of 15% Alamine 336 in: octanol, a 50:50 mixture of oleyl alcohol:octanol or oleyl alcohol. Rapid removal of sulfuric acid, 5-hydroxymethyl and furfural was observed. The rate of acetic acid removal decreased as the pH of the hydrolysate increased. Regeneration of the organic extractant was achieved by back extraction into an aqueous phase containing NaOH and ethanol. A cleaning protocol consisting of flushing the hydrolysate compartment with NaOH and the organic phase compartment with pure organic phase enabled regeneration and reuse of the module. Ethanol yields from hydrolysates detoxified by membrane extraction using 15% Alamine 336 in oleyl alcohol were about 10% higher than those from hydrolysates detoxified using ammonium hydroxide treatment.

  15. Microfluidic polyacrylamide gel electrophoresis with in situ immunoblotting for native protein analysis.

    PubMed

    He, Mei; Herr, Amy E

    2009-10-01

    We introduce an automated immunoblotting method that reports protein electrophoretic mobility and identity in a single streamlined microfluidic assay. Native polyacrylamide gel electrophoresis (PAGE) was integrated with subsequent in situ immunoblotting. Integration of three PA gel elements into a glass microfluidic chip achieved multiple functions, including (1) rapid protein separation via on-chip PAGE, (2) directed electrophoretic transfer of resolved protein peaks to an in-line blotting membrane, and (3) high-efficiency identification of the transferred proteins using antibody-functionalized blotting membranes. In-chip blotting membranes were photopatterned with biotinylated antibody using streptavidin polyacrylamide (PA) thus yielding postseparation sample analysis. No pressure driven flow or fluid valving was required, as the assay was operated by electrokinetically programmed control. A model sample of fluorescently labeled BSA (negative control), alpha-actinin, and prostate specific antigen (PSA) was selected to develop and characterize the assay. A 5 min assay time was required without operator intervention. Optimization of the blotting membrane (geometry, operation, and composition) yielded a detection limit of approximately 0.05 pg (alpha-actinin peak). An important additional blotting fabrication strategy was developed and characterized to allow vanishingly small antibody consumption (approximately 1 microg), as well as end-user customization of the blotting membrane after device fabrication and storage. This first report of rapid on-chip protein PAGE integrated with in situ immunoblotting forms the basis for a sensitive, automated approach applicable to numerous forms of immunoblotting.

  16. 21 CFR 177.1350 - Ethylene-vinyl acetate copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ethylene-vinyl acetate copolymers. 177.1350... Use Food Contact Surfaces § 177.1350 Ethylene-vinyl acetate copolymers. Ethylene-vinyl acetate... with the following prescribed conditions: (a)(1) Ethylene-vinyl acetate copolymers consist of...

  17. Electromembrane extraction and HPLC analysis of haloacetic acids and aromatic acetic acids in wastewater.

    PubMed

    Alhooshani, Khalid; Basheer, Chanbasha; Kaur, Jagjit; Gjelstad, Astrid; Rasmussen, Knut E; Pedersen-Bjergaard, Stig; Lee, Hian Kee

    2011-10-30

    For the first time, haloacetic acids and aromatic acetic acids were extracted from wastewater samples using electromembrane extraction (EME). A thin layer of toluene immobilized on the walls of a polypropylene membrane envelope served as an artificial supported liquid membrane (SLM). The haloacetic acids (HAAs) (chloroacetic acid, dichloroacetic acid, and trifluoroacetic acid) and aromatic acetic acids (phenylacetic acid and p-hydroxyphenylacetic acid) were extracted through the SLM and into an alkalized aqueous buffer solution. The buffer solution was located inside the membrane envelope. The electrical potential difference sustained over the membrane acted as the driving force for the transport of haloacetic acids into the membrane by electrokinetic migration. After extraction, the extracts were analyzed by high-performance liquid chromatography-ultraviolet detection. The detection limits were between 0.072 and 40.3 ng L(-1). The calibration plot linearity was in the range of 5 and 200 μg L(-1) while the correlation coefficients for the analytes ranged from 0.9932 to 0.9967. Relative recoveries were in the range of 87-106%. The extraction efficiency was found to be comparable to that of solid-phase extraction.

  18. Indole-3-acetic acid and fusicoccin cause cytosolic acidification of corn coleoptile cells

    PubMed Central

    Felle, Hubert; Brummer, Benno; Bertl, Adam; Parish, Roger W.

    1986-01-01

    Microelectrodes were used to measure simultaneously the effects of indole-3-acetic acid (IAA) on membrane potential and cytosolic pH of corn coleoptile cells. IAA caused an initial depolarization followed by hyperpolarization, the latter displaying rhythmic oscillations. The extent of the changes in membrane potential was dependent on IAA concentration, and hyperpolarization, but not depolarization, could be detected with concentrations of IAA as low as 10 nM. Membrane hyperpolarization was preceded by a decrease in cytosolic pH. The decrease commenced ≈5 min after adding IAA and continued for 15-20 min before reaching a new steady state ≈0.1 pH unit lower than the original pH. The decrease in pH was readily detectable after treatment with 0.1 μM IAA. Fusicoccin and acetate, which, like IAA, induce elongation growth, caused a similar drop in cytosolic pH and subsequent membrane hyperpolarization, the decrease in pH commencing within seconds. The addition of fusicoccin to IAA-treated cells resulted in a further cytosolic acidification and membrane hyperpolarization. The two substances probably change cytosolic pH via different mechanisms. The results imply that one of the primary effects of auxins in coleoptiles is to lower cytosolic pH. PMID:16593782

  19. Nanofiltration of rhodium tris(triphenylphosphine) catalyst in ethyl acetate solution

    NASA Astrophysics Data System (ADS)

    Shaharun, Maizatul S.; Mustafa, Ahmad K.; Taha, Mohd F.

    2012-09-01

    Solvent resistant nanofiltration (SRNF) using polymer membranes has recently received enhanced attention due to the search for cleaner and more energy-efficient technologies. The large size of the rhodium tris(triphenylphosphine) [HRh(CO)(PPh3)3] catalyst (>400 Da) - relative to other components of the hydroformylation reaction provides the opportunity for a membrane separation based on retention of the catalyst species while permeating the solvent. The compatibility of the solvent-polyimide membrane (DuraMem{trade mark, serif} 200 and DuraMem{trade mark, serif} 500) combinations was assessed in terms of the membrane stability in solvent plus non-zero solvent flux at 2.0 MPa. Good HRh(CO)(PPh3)3 rejection (>0.95) and solvent fluxes of 9.9 L/m2ṡh1 at 2.0 MPa were obtained in the catalyst-ethyl acetate-DuraMem 500 system. The effect of pressure and catalyst concentration on the solvent flux and catalyst rejection was conducted on the catalyst-ethyl acetate-membrane systems. Increasing pressure substantially improved both solvent flux and catalyst rejection, while increasing catalyst concentration was found to be beneficial in terms of substantial increases in catalyst rejection without significantly affecting solvent flux.

  20. High resolution detection system of capillary electrophoresis

    NASA Astrophysics Data System (ADS)

    Wang, Jie; Wang, Li Qiang; Shi, Yan; Zheng, Hua; Lu, Zu Kang

    2007-12-01

    The capillary electrophoresis (CE) with laser induced fluorescence detection (LIFD) system was founded according to confocal theory. The 3-D adjustment of the exciting and collecting optical paths was realized. The photomultiplier tube (PMT) is used and the signals are processed by a software designed by ourselves. Under computer control, high voltage is applied to appropriate reservoirs and to inject and separate DNA samples respectively. Two fluorescent dyes Thiazole Orange (TO) and SYBR Green I were contrasted. With both of the dyes, high signals-to-noise images were obtained with the CE-LIFD system. The single-bases can be distinguished from the electrophoretogram and high resolution of DNA sample separation was obtained.

  1. Combined electrophoresis-electrospray interface and method

    DOEpatents

    Smith, R.D.; Udseth, H.R.; Olivares, J.A.

    1994-10-18

    A system and method for analyzing molecular constituents of a composition sample include: forming a solution of the sample, separating the solution by capillary electrophoresis into an eluent of constituents longitudinally separated according to their relative electrophoretic mobilities, electrospraying the eluent to form a charged spray in which the molecular constituents have a temporal distribution; and detecting or collecting the separated constituents in accordance with the temporal distribution in the spray. A first high-voltage (e.g., 5--100 kVDC) is applied to the solution. The spray is charged by applying a second high voltage (e.g.,{+-}2--8 kVDC) between the eluent at the capillary exit and a cathode spaced in front of the exit. A complete electrical circuit is formed by a conductor which directly contacts the eluent at the capillary exit, or by conduction through a sheath electrode discharged in an annular sheath flow about the capillary exit. 21 figs.

  2. Hybrid slab-microchannel gel electrophoresis system

    DOEpatents

    Balch, J.W.; Carrano, A.V.; Davidson, J.C.; Koo, J.C.

    1998-05-05

    A hybrid slab-microchannel gel electrophoresis system is described. The hybrid system permits the fabrication of isolated microchannels for biomolecule separations without imposing the constraint of a totally sealed system. The hybrid system is reusable and ultimately much simpler and less costly to manufacture than a closed channel plate system. The hybrid system incorporates a microslab portion of the separation medium above the microchannels, thus at least substantially reducing the possibility of non-uniform field distribution and breakdown due to uncontrollable leakage. A microslab of the sieving matrix is built into the system by using plastic spacer materials and is used to uniformly couple the top plate with the bottom microchannel plate. 4 figs.

  3. Cycloaliphatic epoxy resin coating for capillary electrophoresis.

    PubMed

    Shah, Roopa S; Wang, Qinggang; Lee, Milton L

    2002-04-05

    Coating the interior surface of a fused-silica capillary with a polymeric material has long been used in capillary electrophoresis (CE) to reduce or eliminate electroosmotic flow and suppress adsorption. A cycloaliphatic epoxide-based resin was bonded to silane treated capillaries and crosslinked with a curing agent. The epoxy resin coating significantly reduced electroosmotic flow over a pH range of 3-10. This coating was sufficiently hydrophilic to suppress protein adsorption. The epoxy resin coated capillary was used to separate several acidic and basic proteins and peptides. Separation efficiencies greater than 400,000 theoretical plates were achieved. The relative standard deviations in migration times for proteins were <0.8%. Speed and simplicity are important advantages of the coating procedure compared to other published coating methods.

  4. Novel absorption detection techniques for capillary electrophoresis

    SciTech Connect

    Xue, Yongjun

    1994-07-27

    Capillary electrophoresis (CE) has emerged as one of the most versatile separation methods. However, efficient separation is not sufficient unless coupled to adequate detection. The narrow inner diameter (I.D.) of the capillary column raises a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the μM level. Most commercial CE instruments are equipped with incoherent UV-vis lamps. Low-brightness, instability and inefficient coupling of the light source with the capillary limit the further improvement of UV-vis absorption detection in CE. The goals of this research have been to show the utility of laser-based absorption detection. The approaches involve: on-column double-beam laser absorption detection and its application to the detection of small ions and proteins, and absorption detection with the bubble-shaped flow cell.

  5. Capillary Electrophoresis of Mono- and Oligosaccharides.

    PubMed

    Toppazzini, Mila; Coslovi, Anna; Rossi, Marco; Flamigni, Anna; Baiutti, Edi; Campa, Cristiana

    2016-01-01

    This chapter reports an overview of the recent advances in the analysis of mono- and oligosaccharides by capillary electrophoresis (CE); furthermore, relevant reviews and research articles recently published in the field are tabulated. Additionally, pretreatments and procedures applied to uncharged and acidic carbohydrates (i.e., monosaccharides and lower oligosaccharides carrying carboxylate, sulfate, or phosphate groups) are described.Representative examples of such procedures are reported in detail, upon describing robust methodologies for the study of (1) neutral oligosaccharides derivatized by reductive amination and by formation of glycosylamines; (2) sialic acid derivatized with 2-aminoacridone, released from human serum immunoglobulin G; (3) anomeric couples of neutral glycosides separated using borate-based buffers; (4) unsaturated, underivatized oligosaccharides from lyase-treated alginate.

  6. Flow structure in continuous flow electrophoresis chambers

    NASA Technical Reports Server (NTRS)

    Deiber, J. A.; Saville, D. A.

    1982-01-01

    There are at least two ways that hydrodynamic processes can limit continiuous flow electrophoresis. One arises from the sensitivity of the flow to small temerature gradients, especially at low flow rates and power levels. This sensitivity can be suppressed, at least in principle, by providing a carefully tailored, stabilizing temperature gradient in the cooling system that surrounds the flow channel. At higher power levels another limitation arises due to a restructuring of the main flow. This restructuring is caused by buoyancy, which is in turn affected by the electro-osmotic crossflow. Approximate solutions to appropriate partial differential equations have been computed by finite difference methods. One set of results is described here to illustrate the strong coupling between the structure of the main (axial) flow and the electro-osmotic flow.

  7. Combined electrophoresis-electrospray interface and method

    DOEpatents

    Smith, R.P.; Udseth, H.R.; Olivares, J.A.

    1989-12-05

    A system and method for analyzing molecular constituents of a composition sample includes: forming a solution of the sample, separating the solution by capillary electrophoresis into an eluent of constituents longitudinally separated according to their relative electrophoretic mobilities, electrospraying the eluent to form a charged spray in which the molecular constituents have a temporal distribution; and detecting or collecting the separated constituents in accordance with the temporal distribution in the spray. A first high-voltage (e.g., 5--100 kVDC) is applied to the solution. The spray is charged by applying a second high voltage (e.g., [+-]2--8 kVDC) between the eluent at the capillary exit and a cathode spaced in front of the exit. A complete electrical circuit is formed by a conductor which directly contacts the eluent at the capillary exit, or by conduction through a sheath electrode discharged in an annular sheath flow about the capillary exit. 21 figs.

  8. Dating silk by capillary electrophoresis mass spectrometry.

    PubMed

    Moini, Mehdi; Klauenberg, Kathryn; Ballard, Mary

    2011-10-01

    A new capillary electrophoresis mass spectrometry (CE-MS) technique is introduced for age estimation of silk textiles based on amino acid racemization rates. With an L to D conversion half-life of ~2500 years for silk (B. mori) aspartic acid, the technique is capable of dating silk textiles ranging in age from several decades to a few-thousand-years-old. Analysis required only ~100 μg or less of silk fiber. Except for a 2 h acid hydrolysis at 110 °C, no other sample preparation is required. The CE-MS analysis takes ~20 min, consumes only nanoliters of the amino acid mixture, and provides both amino acid composition profiles and D/L ratios for ~11 amino acids.

  9. Combined electrophoresis-electrospray interface and method

    DOEpatents

    Smith, Richard D.; Udseth, Harold R.; Olivares, Jose A.

    1994-10-18

    A system and method for analyzing molecular constituents of a composition sample includes: forming a solution of the sample, separating the solution by capillary electrophoresis into an eluent of constituents longitudinally separated according to their relative electrophoretic mobilities, electrospraying the eluent to form a charged spray in which the molecular constituents have a temporal distribution; and detecting or collecting the separated constituents in accordance with the temporal distribution in the spray. A first high-voltage (e.g., 5-100 KVDC) is applied to the solution. The spray is charged by applying a second high voltage (e.g., .+-.2-8 KVDC) between the eluent at the capillary exit and a cathode spaced in front of the exit. A complete electrical circuit is formed by a conductor which directly contacts the eluent at the capillary exit, or by conduction through a sheath electrode discharged in an annular sheath flow about the capillary exit.

  10. Combined electrophoresis-electrospray interface and method

    DOEpatents

    Smith, Richard P.; Udseth, Harold R.; Olivares, Jose A.

    1989-01-01

    A system and method for analyzing molecular constituents of a composition sample includes: forming a solution of the sample, separating the solution by capillary electrophoresis into an eluent of constituents longitudinally separated according to their relative electrophoretic mobilities, electrospraying the eluent to form a charged spray in which the molecular constituents have a temporal distribution; and detecting or collecting the separated constituents in accordance with the temporal distribution in the spray. A first high-voltage (e.g., 5-100 KVDC) is applied to the solution. The spray is charged by applying a second high voltage (e.g., .+-.2-8 KVDC) between the eluent at the capillary exit and a cathode spaced in front of the exit. A complete electrical circuit is formed by a conductor which directly contacts the eluent at the capillary exit, or by conduction through a sheath electrode discharged in an annular sheath flow about the capillary exit.

  11. Radiation effects on bovine taste bud membranes

    SciTech Connect

    Shatzman, A.R.; Mossman, K.L.

    1982-11-01

    In order to investigate the mechanisms of radiation-induced taste loss, the effects of radiation on preparations of enriched bovine taste bud membranes were studied. Taste buds containing circumvallate papilae, and surrounding control epithelial tissues devoid of taste buds, were obtained from steers and given radiation doses of 0-7000 cGy (rad). Tissue fractions were isolated into membrane-enriched and heterogeneous components using differential and sucrose gradient centrifugation of tissue homogenates. The yield of membranes, as measured by protein content in the buoyant membrane-enriched fractions, was reduced in quantity with increasing radiation dose. The relation between radiation dose and membrane quantity in membrane-enriched fractions could be fit by a simple exponential model with taste bud-derived membranes twice as radiosensitive as membranes from control epithelial tissue. Binding of sucrose, sodium, and acetate and fluoride stimulation of adenylate cyclase were nearly identical in both irradiated and nonirradiated intact membranes. Radiation had no effect on fractions of heterogeneous components. While it is not clear what changes are occurring in enriched taste cell membranes, damage to membranes may play an important role in the taste loss observed in patients following radiotherapy.

  12. Precise, fast, and flexible determination of protein interactions by affinity capillary electrophoresis: part 3: anions.

    PubMed

    Xu, Yuanhong; Redweik, Sabine; El-Hady, Deia Abd; Albishri, Hassan M; Preu, Lutz; Wätzig, Hermann

    2014-08-01

    The binding of physiologically anionic species or negatively charged drug molecules to proteins is of great importance in biochemistry and medicine. Since affinity capillary electrophoresis (ACE) has already proven to be a suitable analytical tool to study the influence of ions on proteins, this technique was applied here for comprehensively studying the influence of various anions on proteins of BSA, β-lactoglobulin, ovalbumin, myoglobin, and lysozyme. The analysis was performed using different selected anions of succinate, glutamate, phosphate, acetate, nitrate, iodide, thiocyanate, and pharmaceuticals (salicylic acid, aspirin, and ibuprofen) that exist in the anionic form at physiological pH 7.4. Due to the excellent repeatability and precision of the ACE measurements, not necessarily strong but significant influences of the anions on the proteins were found in many cases. Different influences in the observed bindings indicated change of charge, mass, or conformational changes of the proteins due to the binding with the studied anions. Combining the mobility-shift and pre-equilibrium ACE modes, rapidity and reversibility of the protein-anion bindings were discussed. Further, circular dichroism has been used as an orthogonal approach to characterize the interactions between the studied proteins and anions to confirm the ACE results. Since phosphate and various anions from amino acids and small organic acids such as succinate or acetate are present in very high concentrations in the cellular environment, even weak influences are certainly relevant as well.

  13. Tested Demonstrations: Buffer Capacity of Various Acetic Acid-Sodium Acetate Systems: A Lecture Experiment.

    ERIC Educational Resources Information Center

    Donahue, Craig J.; Panek, Mary G.

    1985-01-01

    Background information and procedures are provided for a lecture experiment which uses indicators to illustrate the concept of differing buffer capacities by titrating acetic acid/sodium acetate buffers with 1.0 molar hydrochloric acid and 1.0 molar sodium hydroxide. A table with data used to plot the titration curve is included. (JN)

  14. Acetylation of Starch with Vinyl Acetate in Imidazolium Ionic Liquids and Characterization of Acetate Distribution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch was acetylated with vinyl acetate in different 1-butyl-3-methylimidazolium (BMIM) salts as solvent in effort to produce starches with different acetylation patterns. Overall degree of substitution was much higher for basic anions such as acetate and dicyanimide (dca) than for neutral anions ...

  15. Acetic acid production from food wastes using yeast and acetic acid bacteria micro-aerobic fermentation.

    PubMed

    Li, Yang; He, Dongwei; Niu, Dongjie; Zhao, Youcai

    2015-05-01

    In this study, yeast and acetic acid bacteria strains were adopted to enhance the ethanol-type fermentation resulting to a volatile fatty acids yield of 30.22 g/L, and improve acetic acid production to 25.88 g/L, with food wastes as substrate. In contrast, only 12.81 g/L acetic acid can be obtained in the absence of strains. The parameters such as pH, oxidation reduction potential and volatile fatty acids were tested and the microbial diversity of different strains and activity of hydrolytic ferment were investigated to reveal the mechanism. The optimum pH and oxidation reduction potential for the acetic acid production were determined to be at 3.0-3.5 and -500 mV, respectively. Yeast can convert organic matters into ethanol, which is used by acetic acid bacteria to convert the organic wastes into acetic acid. The acetic acid thus obtained from food wastes micro-aerobic fermentation liquid could be extracted by distillation to get high-pure acetic acid.

  16. Inexpensive and Safe DNA Gel Electrophoresis Using Household Materials

    ERIC Educational Resources Information Center

    Ens, S.; Olson, A. B.; Dudley, C.; Ross, N. D., III; Siddiqi, A. A.; Umoh, K. M.; Schneegurt, M. A.

    2012-01-01

    Gel electrophoresis is the single most important molecular biology technique and it is central to life sciences research, but it is often too expensive for the secondary science classroom or homeschoolers. A simple safe low-cost procedure is described here that uses household materials to construct and run DNA gel electrophoresis. Plastic…

  17. Gel Electrophoresis on a Budget to Dye for

    ERIC Educational Resources Information Center

    Yu, Julie H.

    2010-01-01

    Gel electrophoresis is one of the most important tools used in molecular biology and has facilitated the entire field of genetic engineering by enabling the separation of nucleic acids and proteins. However, commercial electrophoresis kits can cost up to $800 for each setup, which is cost prohibitive for most classroom budgets. This article…

  18. 21 CFR 862.2485 - Electrophoresis apparatus for clinical use.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Electrophoresis apparatus for clinical use. 862.2485 Section 862.2485 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Instruments § 862.2485 Electrophoresis apparatus for clinical use. (a) Identification. An...

  19. 21 CFR 862.2485 - Electrophoresis apparatus for clinical use.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Electrophoresis apparatus for clinical use. 862.2485 Section 862.2485 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Instruments § 862.2485 Electrophoresis apparatus for clinical use. (a) Identification. An...

  20. 21 CFR 862.2485 - Electrophoresis apparatus for clinical use.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Electrophoresis apparatus for clinical use. 862.2485 Section 862.2485 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Instruments § 862.2485 Electrophoresis apparatus for clinical use. (a) Identification. An...

  1. Ice-structuring mechanism for zirconium acetate.

    PubMed

    Deville, Sylvain; Viazzi, Céline; Guizard, Christian

    2012-10-23

    The control of ice nucleation and growth is critical in many natural and engineering situations. However, very few compounds are able to interact directly with the surface of ice crystals. Ice-structuring proteins, found in certain fish, plants, and insects, bind to the surface of ice, thereby controlling their growth. We recently revealed the ice-structuring properties of zirconium acetate, which are similar to those of ice-structuring proteins. Because zirconium acetate is a salt and therefore different from proteins having ice-structuring properties, its ice-structuring mechanism remains unelucidated. Here we investigate this ice-structuring mechanism through the role of the concentration of zirconium acetate and the ice crystal growth velocity. We then explore other compounds presenting similar functional groups (acetate, hydroxyl, or carboxylic groups). On the basis of these results, we propose that zirconium acetate adopts a hydroxy-bridged polymer structure that can bind to the surface of the ice crystals through hydrogen bonding, thereby slowing down the ice crystal growth.

  2. A mammalian acetate switch regulates stress erythropoiesis

    PubMed Central

    Xu, Min; Nagati, Jason S.; Xie, Jian; Li, Jiwen; Walters, Holly; Moon, Young-Ah; Gerard, Robert D.; Huang, Chou-Long; Comerford, Sarah A.; Hammer, Robert E.; Horton, Jay D.; Chen, Rui; Garcia, Joseph A.

    2014-01-01

    Endocrine erythropoietin (Epo), which is synthesized in the kidney or liver of adult mammals, controls erythrocyte production and is regulated by the stress-responsive transcription factor Hypoxia Inducible Factor 2 (HIF-2). We previously reported that the lysine acetyltransferase Cbp is required for HIF-2α acetylation and efficient HIF-2 dependent Epo induction during hypoxia. We now show these processes require acetate-dependent acetyl CoA synthetase 2 (Acss2). In Hep3B hepatoma cells and in Epo-generating organs of hypoxic or acutely anemic mice, acetate levels increase and Acss2 is required for HIF-2α acetylation, Cbp/HIF-2α complex formation and recruitment to the Epo enhancer, and efficient Epo induction. In acutely anemic mice, acetate supplementation augments stress erythropoiesis in an Acss2-dependent manner. In acquired and genetic chronic anemia mouse models, acetate supplementation also increases Epo expression and resting hematocrits. Thus, a mammalian stress-responsive acetate switch controls HIF-2 signaling and Epo induction during pathophysiological states marked by tissue hypoxia. PMID:25108527

  3. The CgHaa1-Regulon Mediates Response and Tolerance to Acetic Acid Stress in the Human Pathogen Candida glabrata

    PubMed Central

    Bernardo, Ruben T.; Cunha, Diana V.; Wang, Can; Pereira, Leonel; Silva, Sónia; Salazar, Sara B.; Schröder, Markus S.; Okamoto, Michiyo; Takahashi-Nakaguchi, Azusa; Chibana, Hiroji; Aoyama, Toshihiro; Sá-Correia, Isabel; Azeredo, Joana; Butler, Geraldine; Mira, Nuno Pereira

    2016-01-01

    To thrive in the acidic vaginal tract, Candida glabrata has to cope with high concentrations of acetic acid. The mechanisms underlying C. glabrata tolerance to acetic acid at low pH remain largely uncharacterized. In this work, the essential role of the CgHaa1 transcription factor (encoded by ORF CAGL0L09339g) in the response and tolerance of C. glabrata to acetic acid is demonstrated. Transcriptomic analysis showed that CgHaa1 regulates, directly or indirectly, the expression of about 75% of the genes activated under acetic acid stress. CgHaa1-activated targets are involved in multiple physiological functions including membrane transport, metabolism of carbohydrates and amino acids, regulation of the activity of the plasma membrane H+-ATPase, and adhesion. Under acetic acid stress, CgHaa1 increased the activity and the expression of the CgPma1 proton pump and contributed to increased colonization of vaginal epithelial cells by C. glabrata. CgHAA1, and two identified CgHaa1-activated targets, CgTPO3 and CgHSP30, are herein demonstrated to be determinants of C. glabrata tolerance to acetic acid. The protective effect of CgTpo3 and of CgHaa1 was linked to a role of these proteins in reducing the accumulation of acetic acid inside C. glabrata cells. In response to acetic acid stress, marked differences were found in the regulons controlled by CgHaa1 and by its S. cerevisiae ScHaa1 ortholog, demonstrating a clear divergent evolution of the two regulatory networks. The results gathered in this study significantly advance the understanding of the molecular mechanisms underlying the success of C. glabrata as a vaginal colonizer. PMID:27815348

  4. The CgHaa1-Regulon Mediates Response and Tolerance to Acetic Acid Stress in the Human Pathogen Candida glabrata.

    PubMed

    Bernardo, Ruben T; Cunha, Diana V; Wang, Can; Pereira, Leonel; Silva, Sónia; Salazar, Sara B; Schröder, Markus S; Okamoto, Michiyo; Takahashi-Nakaguchi, Azusa; Chibana, Hiroji; Aoyama, Toshihiro; Sá-Correia, Isabel; Azeredo, Joana; Butler, Geraldine; Mira, Nuno Pereira

    2017-01-05

    To thrive in the acidic vaginal tract, Candida glabrata has to cope with high concentrations of acetic acid. The mechanisms underlying C. glabrata tolerance to acetic acid at low pH remain largely uncharacterized. In this work, the essential role of the CgHaa1 transcription factor (encoded by ORF CAGL0L09339g) in the response and tolerance of C. glabrata to acetic acid is demonstrated. Transcriptomic analysis showed that CgHaa1 regulates, directly or indirectly, the expression of about 75% of the genes activated under acetic acid stress. CgHaa1-activated targets are involved in multiple physiological functions including membrane transport, metabolism of carbohydrates and amino acids, regulation of the activity of the plasma membrane H(+)-ATPase, and adhesion. Under acetic acid stress, CgHaa1 increased the activity and the expression of the CgPma1 proton pump and contributed to increased colonization of vaginal epithelial cells by C. glabrata CgHAA1, and two identified CgHaa1-activated targets, CgTPO3 and CgHSP30, are herein demonstrated to be determinants of C. glabrata tolerance to acetic acid. The protective effect of CgTpo3 and of CgHaa1 was linked to a role of these proteins in reducing the accumulation of acetic acid inside C. glabrata cells. In response to acetic acid stress, marked differences were found in the regulons controlled by CgHaa1 and by its S. cerevisiae ScHaa1 ortholog, demonstrating a clear divergent evolution of the two regulatory networks. The results gathered in this study significantly advance the understanding of the molecular mechanisms underlying the success of C. glabrata as a vaginal colonizer.

  5. Removal of bisphenol A (BPA) from water by various nanofiltration (NF) and reverse osmosis (RO) membranes.

    PubMed

    Yüksel, Suna; Kabay, Nalan; Yüksel, Mithat

    2013-12-15

    The removal of an endocrine disrupting compound, bisphenol A (BPA), from model solutions by selected nanofiltration (NF) and reverse osmosis (RO) membranes was studied. The commercially available membranes NF 90, NF 270, XLE BWRO, BW 30 (Dow FilmTech), CE BWRO and AD SWRO (GE Osmonics) were used to compare their performances for BPA removal. The water permeability coefficients, rejection of BPA and permeate flux values were calculated for all membranes used. No significant changes in their BPA removal were observed for all tight polyamide based NF and RO membranes tested except for loose NF 270 membrane. The polyamide based membranes exhibited much better performance than cellulose acetate membrane for BPA removal. Almost a complete rejection (≥ 98%) for BPA was obtained with three polyamide based RO membranes (BW 30, XLE BWRO and AD SWRO). But cellulose acetate based CE BWRO membrane offered a low and variable (10-40%) rejection for BPA.

  6. Organization of the Sec61 translocon, studied by high resolution native electrophoresis.

    PubMed

    Dejgaard, Kurt; Theberge, Jean-Francois; Heath-Engel, Hannah; Chevet, Eric; Tremblay, Michel L; Thomas, David Y

    2010-04-05

    Cotranslational translocation of polypeptides into the ER is controlled by the dynamic interaction of ribosome and translocon components. Analysis of the steps involved in this process by high resolution techniques such as gel electrophoresis is precluded by the high molecular masses of these complexes. We show, here, that modifications to standard native electrophoresis protocols can overcome these problems and lead to an increase in mass range and resolution. Using the modified technique, we show that ER ribosome anchored membrane protein (RAMP) complexes resolve into 3 stable and semistable complexes which range in size between 4 and 8 MDa and are sensitive to relevant concentrations of divalent metals. We demonstrate the molecular composition of the complexes and identify a number of modular components that differentiate them. The components that are common to all three RAMP complexes include the OST translocon subcomplex, Glucosidase I and microtubule tethering protein CLIMP63. The two larger complexes further include the kinesin motor binding protein p180 and Sec61, and the largest complex includes the TRAP translocon component and apoptotic regulator BAP31. On the lumenal side, the BiP cochaperone ERdj3 resides with the three RAMP complexes. Our observations may hint at how subcompartmentalization is achieved in the ER membrane continuum.

  7. Modification of gel architecture and TBE/TAE buffer composition to minimize heating during agarose gel electrophoresis.

    PubMed

    Sanderson, Brian A; Araki, Naoko; Lilley, Jennifer L; Guerrero, Gilberto; Lewis, L Kevin

    2014-06-01

    Agarose gel electrophoresis of DNA and RNA is routinely performed using buffers containing either Tris, acetate, and EDTA (TAE) or Tris, borate, and EDTA (TBE). Gels are run at a low, constant voltage (∼10 V/cm) to minimize current and asymmetric heating effects, which can induce band artifacts and poor resolution. In this study, alterations of gel structure and conductive media composition were analyzed to identify factors causing higher electrical currents during horizontal slab gel electrophoresis. Current was reduced when thinner gels and smaller chamber buffer volumes were used, but was not influenced by agarose concentration or the presence of ethidium bromide. Current was strongly dependent on the amount and type of EDTA used and on the concentrations of the major acid-base components of each buffer. Interestingly, resolution and the mobilities of circular versus linear plasmid DNAs were also affected by the chemical form and amount of EDTA. With appropriate modifications to gel structure and buffer constituents, electrophoresis could be performed at high voltages (20-25 V/cm), reducing run times by up to 3-fold. The most striking improvements were observed with small DNAs and RNAs (10-100 bp): high voltages and short run times produced sharper bands and higher resolution.

  8. Separation and analysis of triazine herbcide residues by capillary electrophoresis.

    PubMed

    Elbashir, Abdalla A; Aboul-Enein, Hassan Y

    2015-06-01

    Triazines are widely used in agriculture around the world as selective pre- and post-emergence herbicides for the control of broad leaf and grassy weeds. With high toxicity and persistence, triazines can contaminate the environment and crops, so the development of rapid and sensitive methods for the determination of different triazines is necessary. Capillary electrophoresis comprises a group of techniques used to separate chemical mixtures. Analytical separation is based on different electrophoretic mobilities. This review focuses on the analysis of triazine herbicides with different modes of capillary electrophoresis, including capillary zone electrophoresis, micellar electrokinetic capillary electrophoresis, capillary electrochromatography and nonaqueous capillary electrophoresis. Determinations of triazines in various matrices such as surface water, groundwater, vegetables, soil and grains are emphasized.

  9. DNA gel electrophoresis: the reptation model(s).

    PubMed

    Slater, Gary W

    2009-06-01

    DNA gel electrophoresis has been the most important experimental tool to separate DNA fragments for several decades. The introduction of PFGE in the 1980s and capillary gel electrophoresis in the 1990s made it possible to study, map and sequence entire genomes. Explaining how very large DNA molecules move in a gel and why PFGE is needed to separate them has been an active field of research ever since the launch of the journal Electrophoresis. This article presents a personal and historical overview of the development of the theory of gel electrophoresis, focusing on the reptation model, the band broadening mechanisms, and finally the factors that limit the read length and the resolution of electrophoresis-based sequencing systems. I conclude with a short discussion of some of the questions that remain unanswered.

  10. Relaxometry, luminescence measurements, electrophoresis, and animal biodistribution of lanthanide(III) complexes of some polyaza macrocyclic acetates containing pyridine

    SciTech Connect

    Kim, W.D.; Sherry, A.D.; Kiefer, G.E.; McMillan, K.; Maton, F.; Muller, R.N.

    1995-04-12

    Four Gd{sup 3+} complexes [Gd(BP2A){sup +}, Gd(PC2A){sup +}, Gd(PCTA){sup 0}, and Gd(BPO4A){sup {minus}}] with polyazamacrocyclic ligands that contain a pyridine moiety were prepared and examined for possible use as MRI contrast enhancement agents. The authors estimated the number of inner sphere water molecules (q{sub Gd}) for the Gd{sup 3+} complexes from the values of q found for the Tb{sup 3+} and/or Eu{sup 3+} complexes by luminescence lifetime measurements. It was estimated that q{sub Gd} = 3.5, 3.3, 2.4, and 0.2 for Gd(BP2A){sup +}, Gd(PC2A){sup +}, Gd(PCTA){sup 0}, and Gd(BPO4A){sup {minus}}, respectively. The inner sphere relaxivities (r{sub 1,inner}) of these tetraaza macrocyclic complexes were higher than that of Gd(DOTA){sup {minus}} [i.e. 6.79 for Gd(BP2A){sup +}, 6.21 for Gd(PC2A){sup +}, and 4.60 for Gd(PCTA){sup 0} mM{sup {minus}1}s{sup {minus}1} at 40 MHz and 25{degrees}C], but the normalized relaxivities per q{sub Gd} (1.94, 1.88, and 1.92 mM{sup {minus}1}s{sup {minus}1}, respectively) were comparable to that of Gd(DOTA){sup {minus}}. A quantitative treatment of the NMRD profiles based on Solomon-Bloembergen-Morgan theory, using the NMRD profile of Gd(BPO4A){sup {minus}} to correct for an outer sphere contribution, showed that the complexes exhibit characteristics similar to that of Gd(DOTA){sup {minus}} but with shorter electronic relaxation times. Tissue biodistribution results using radioactive {sup 153}Sm and {sup 159}Gd complexes in rats indicate that the cationic [{sup 153}Sm-(BP2A){sup +} and {sup 153}Sm(PC2A){sup +}] complexes accumulate preferably in the bone tissue while the neutral [{sup 153}Sm-(PCTA){sup 0}] and anionic [{sup 153}Sm(BPO4A){sup {minus}}] complexes appear to have renal clearances similar to those of other low molecular weight contrast agents [i.e. Gd(DTPA){sup 2{minus}} and Gd(DOTA){sup {minus}}].

  11. Agarose gel electrophoresis and polyacrylamide gel electrophoresis for visualization of simple sequence repeats.

    PubMed

    Anderson, James; Wright, Drew; Meksem, Khalid

    2013-01-01

    In the modern age of genetic research there is a constant search for ways to improve the efficiency of plant selection. The most recent technology that can result in a highly efficient means of selection and still be done at a low cost is through plant selection directed by simple sequence repeats (SSRs or microsatellites). The molecular markers are used to select for certain desirable plant traits without relying on ambiguous phenotypic data. The best way to detect these is the use of gel electrophoresis. Gel electrophoresis is a common technique in laboratory settings which is used to separate deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) by size. Loading DNA and RNA onto gels allows for visualization of the size of fragments through the separation of DNA and RNA fragments. This is achieved through the use of the charge in the particles. As the fragments separate, they form into distinct bands at set sizes. We describe the ability to visualize SSRs on slab gels of agarose and polyacrylamide gel electrophoresis.

  12. Dynamic Protonation Equilibrium of Solvated Acetic Acid

    SciTech Connect

    Gu, Wei; Frigato, Tomaso; Straatsma, TP; Helms, Volkhard H.

    2007-04-13

    For the first time, the dynamic protonation equilibrium between an amino acid side chain analogue and bulk water as well as the diffusion properties of the excess proton were successfully reproduced through unbiased computer simulations. During a 50 ns Q-HOP MD simulation, two different regimes of proton transfer were observed. Extended phases of frequent proton swapping between acetic acid and nearby water were separated by phases where the proton freely diffuses in the simulation box until it is captured again by acetic acid. The pKa of acetic acid was calculated around 3.0 based on the relative population of protonated and deprotonated states and the diffusion coefficient of excess proton was computed from the average mean squared displacement in the simulation. Both calculated values agree well with the experimental measurements.

  13. The physicochemical property characterization of agar acetate.

    PubMed

    Xia, Kai; Liu, Xin; Zhao, Jingkun; Zhang, Xiaodong

    2014-09-22

    A series of agar acetates with different degree of substitution (DS) were prepared, and their properties were determined and analyzed. The results showed that the gelling temperature, the gel melting temperature, the gel strength, the gel hardness, the gel fracturability, the gel springiness and the solution apparent viscosity of agar acetates all decreased except that their gel cohesiveness increased with the increase of DS. The variation process of agar molecules in solution from coil to helix could be also observed by measuring solution optical rotation in a lower concentration at which even the solution could not form a gel. The gel skeleton structures of agar acetates were of porous network structures, and the pores became smaller and denser with the increase of DS. After acetylation, the water holding capacity of the agar was improved, but its thermal stability was lowered.

  14. Microhydration of Neutral and Charged Acetic Acid.

    PubMed

    Krishnakumar, Parvathi; Maity, Dilip Kumar

    2017-01-19

    A systematic theoretical study has been carried out on the effect of sequential addition of water molecules to neutral and mono positively charged acetic acid molecules by applying first principle based electronic structure theory. Geometry, dipole moment, and polarizability of hydrated clusters of neutral and mono positively charged acetic acid of the type CH3COOH·nH2O (n = 1-8) and [CH3COOH·nH2O](+) (n = 1, 2) are calculated at the ωB97X-D/aug-cc-pVDZ level of theory. Free energies of formation of the hydrated acid clusters, at different temperatures and pressures are determined. Solvent stabilization energy and interaction energy are also calculated at the CCSD(T)/6-311++G(d,p) level of theory. It is observed that in the case of neutral acetic acid, proton transfer from the acid molecule to solvent water molecules does not occur even with eight water molecules and the acid molecule remains in the undissociated form. High-energy equilibrium structures showing dissociation of acetic acid are obtained in case of hexahydrated and larger hydrated clusters only. However, dissociation of mono positively charged acetic acid occurs with just two water molecules. Interestingly, it is noted that in the case of dissociation, calculated bond dipole moments of the dissociating bonds of acetic acid in microhydated clusters shows a characteristic feature. IR spectra of CH3COOH·nH2O (n = 1-8) and [CH3COOH·nH2O](+) (n = 1-3) clusters are simulated and compared with the available experimental data.

  15. Comparison between agarose gel electrophoresis and capillary electrophoresis for variable numbers of tandem repeat typing of Mycobacterium tuberculosis.

    PubMed

    Yokoyama, Eiji; Kishida, Kazunori; Uchimura, Masako; Ichinohe, Sadato

    2006-06-01

    Variable numbers of tandem repeat (VNTR) typing of Mycobacterium tuberculosis was performed on 54 strains including 23 strains derived from 9 outbreaks. PCR amplicon sizes of 12 mycobacterial interspersed repetitive unit tandem repeat loci were measured using both agarose gel electrophoresis and capillary electrophoresis. Similarities using agarose gel electrophoresis of Euclidian distances among the 23 strains derived from the 9 outbreaks were significantly lower than that using capillary electrophoresis (Wilcoxon signed ranks test, P < 0.01). By clustering analysis using unweighted pair group method using arithmetic averages, all of the 23 strains derived from the 9 outbreaks were each clustered with more than 90% similarities based on the distance using capillary electrophoresis. In contrast, differential clusters with more than 90% similarity were observed with only 7 strains derived from 3 outbreaks when analyzed by agarose gel electrophoresis. These results indicated that measurement of PCR amplicon size of tandem repeat loci should be carried out using capillary electrophoresis and that agarose gel electrophoresis is not suitable for clustering analysis of M. tuberculosis VNTR typing.

  16. Simple differential detection of Entamoeba histolytica and Entamoeba dispar in fresh stool specimens by sodium acetate-acetic acid-formalin concentration and PCR.

    PubMed

    Troll, H; Marti, H; Weiss, N

    1997-07-01

    Amoebiasis is caused by two distinct species, a pathogenic form (Entamoeba histolytica) and a nonpathogenic form (Entamoeba dispar), which are morphologically identical. Although the distinction between these two species is of great clinical importance, the methods developed for this purpose either are very time-consuming or involve laborious procedures for isolation of the DNA. We report here a simple PCR method starting with fresh stool specimen that allows for the sensitive and reliable distinction between E. histolytica and E. dispar. After initial concentration by the sodium acetate-acetic acid-formalin (SAF) method and digestion with proteinase K, a 0.88-kb sequence of the multicopy 16S rRNA gene served as a target for PCR amplification. The method starting with unpreserved specimens proved to be very sensitive and was not influenced by the quick exposure to SAF fixative during the initial concentration step. However, storage in SAF fixative prior to testing resulted in a decreased sensitivity within 2 days. The detection limit of the method was as low as one copy of the 16S rRNA gene. No cross-reactivity was observed with other common intestinal protozoa. Mixed infections involving both E. histolytica and E. dispar could easily be detected at a ratio of 1:10,000 by agarose gel electrophoresis or a DNA hybridization immunoassay.

  17. Multicomponent membranes

    DOEpatents

    Kulprathipanja, Santi; Kulkarni, Sudhir S.; Funk, Edward W.

    1988-01-01

    A multicomponent membrane which may be used for separating various components which are present in a fluid feed mixture comprises a mixture of a plasticizer such as a glycol and an organic polymer cast upon a porous organic polymer support. The membrane may be prepared by casting an emulsion or a solution of the plasticizer and polymer on the porous support, evaporating the solvent and recovering the membrane after curing.

  18. Effect of lead on erythrocyte membranes.

    PubMed Central

    Fukumoto, K; Karai, I; Horiguchi, S

    1983-01-01

    The effect of blood lead on erythrocyte membrane proteins was studied in 28 workers from a scrap lead refining factory and in 18 controls working in railway construction. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of the polypeptides in the erythrocyte membrane showed that bands 3 and 4.1 had significantly decreased while bands 2.3, 6, and 7 had significantly increased in the lead workers compared with the controls. For the lead workers, the correlation coefficients between blood lead and bands 2.3 and 3 were r = 0.545 (p less than 0.01) and r = -0.51 (p less than 0.01) respectively. These results suggest that the decrease in erythrocyte membrane permeability results from a decrease in the membrane transfer protein responsible for band 3. Images PMID:6830722

  19. Recovering/concentrating of hemicellulosic sugars and acetic acid by nanofiltration and reverse osmosis from prehydrolysis liquor of kraft based hardwood dissolving pulp process.

    PubMed

    Ahsan, Laboni; Jahan, M Sarwar; Ni, Yonghao

    2014-03-01

    This work investigated the feasibility of recovering and concentrating sugars and acetic acid (HAc) from prehydrolysis liquor (PHL) of the kraft-based dissolving pulp process prior to fermentation of hemicellulosic sugars, by the combination of activated carbon adsorption, nanofiltration (NF) and reverse osmosis (RO) processes. To reduce the fouling PHL was subjected to adsorption on activated carbon, then the treated PHL (TPHL) passed through a nanofiltration (NF DK) membrane to retain the sugars, and the permeate of acetic acid rich solution was passed through a reverse osmosis membrane (RO SG). It was found that for NF process sugars were concentrated from 48 to 227g/L at a volume reduction factor (VRF) of 5 while 80 to 90% of acetic acid was permeated. For the reverse osmosis process, 68% of acetic acid retention was achieved at pH 4.3 and 500 psi pressure and the HAc concentration increased from 10 to 50g/L.

  20. Purification of fibrinogen and virus removal using preparative electrophoresis.

    PubMed

    Gilbert, A; Evtushenko, M; Nair, H

    2001-01-01

    The Gradiflow is a novel, scalable preparative electrophoresis technique that uses the dual characteristics of size and charge to isolate target macro- and micromolecules from complex biological solutions. It does this with high resolution and in rapid time. The mild buffers are used to assist in retaining biological activity of the isolated protein. Gradiflow technology employs a sandwich of three polyacrylamide membranes configured to allow passage of macromolecules ranging in size from 10 kDa to 1,500 kDa. Fibrinogen was isolated from cryoprecipitate 1 using a single phase process. This separation was achieved within three hours with yields of 85%. Purified fibrinogen was then characterized using biophysical characterization of fibrin clot structure and compared with clots derived from a commercially available product and human plasma. Significantly, clots developed from Gradiflow fibrinogen had characteristics closer to human plasma. Viral removal characteristics of the Gradiflow were investigated by spiking the source material (cryoprecipitate 1) with canine parvovirus and testing for its presence in the isolated fibrinogen using PCR. Parvo removal was found to be greater than 4 logs and was achieved during the purification process. The Gradiflow offers the advantage of large-scale separation of macromolecules and provides a new approach to fibrinogen separation that is quite distinct from other present-day technologies. The technology is capable of isolating protein with high purity, recovery, and functionality in combination with the removal of viruses during the purification. Furthermore, it is capable of integrating into present production systems, significantly improving yield and functionality of target molecules.