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1

Regeneration of Cellulose Acetate Membranes.  

National Technical Information Service (NTIS)

Several simple methods for in situ one-step regeneration of both flux and salt-retention properties of service-deteriorated membranes have been developed. Membranes have been successfully regenerated using hot, 4% acetic acid, and a one-step cleaning meth...

P. A. Cantor, W. S. Higley, C. W. Saltonstall

1970-01-01

2

Drying Cellulose Acetate Reverse Osmosis Membranes.  

National Technical Information Service (NTIS)

The membranes currently used in reverse osmosis for desalination are made of cellulose acetate. Modified membranes, because they contain a large number of pores, contain large quantities of water, 60 to 70 wt. %. If this water is allowed to evaporate unde...

K. D. Vos, F. O. Burris

1967-01-01

3

Supported molecular matrix electrophoresis: a new membrane electrophoresis for characterizing glycoproteins.  

PubMed

Protein blotting is often used for identification and characterization of proteins on a membrane to which proteins separated by gel electrophoresis are transferred. The transferring process is sometimes problematic, in particular, for mucins and proteoglycans. 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 as the separation support. Proteins separated by this method can be immunoblotted without any transferring procedures. PMID:25117247

Matsuno, Yu-ki; Kameyama, Akihiko

2014-01-01

4

Fabricating PFPE Membranes for Capillary Electrophoresis  

NASA Technical Reports Server (NTRS)

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).

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

2009-01-01

5

Comparison of Capillary Electrophoresis with Cellulose Acetate Electrophoresis for the Screening of Hemoglobinopathies  

PubMed Central

Background ?-thalassemia is primarily found in individuals of Mediterranean and Southeast Asian ancestry. With rapid growth in the Southeast Asian segments of the Korean population, the geographic distribution of hemoglobinopathies is expected to become significantly different from what it is today. In this study, Hb fractions were measured in patients with hypochromic microcytosis to detect thalassemia and Hb variants. To evaluate the feasibility of replacing cellulose acetate electrophoresis (CA) with capillary electrophoresis (CE) in a clinical laboratory, both techniques were performed and the outcomes were compared. Methods To evaluate hemoglobinopathies, complete blood cell counts (CBC), CA, and CE were carried out on samples from healthy and microcytic hypochromic groups. The microcytic hypochromic group consisted of 103 patients whose mean corpuscular volume (MCV) was less than 75 fL and mean corpuscular hemoglobin (MCH) was less than 24 pg. Quantitative analysis of Hb fractions was performed on 143 whole blood samples. Results There was a good correlation for measurements of HbA (r=0.9370, P<0.0001), HbA2 (r=0.8973 P<0.0001), and HbF (r= 0.8010, P=0.0304) between the two methods. In the microcytic hypochromic group, there were 29 cases (28.2%) with decreased HbA2, 2 cases (1.9%) with increased HbA2, 3 cases (2.9%) with increased HbF, and 2 cases (1.9%) with increased HbA2 and HbF. Conclusions CE is comparable to CA for reliable measurement of Hb fractions. It is suitable for screening of hemoglobinopathies in many clinical laboratories. PMID:22016676

Kim, Ji-Eun; Kim, Bo-Ram; Woo, Kwang-Sook; Kim, Jeong-Man; Park, Joo-In

2011-01-01

6

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

PubMed

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. PMID:24853731

Pielesz, Anna; Paluch, Jadwiga

2014-08-01

7

Permeability of cellulose acetate membranes to selected solutes  

Microsoft Academic Search

The permeability of cellulose 2.5-acetate films to several electrolytes and nonelectrolytes was measured. Permeabilities were determined by a desorption-rate method in which diffusion and distribution coefficients were measured. The rejection of the same solutes by modified cellulose acetate membranes in reverse osmosis experiments was also measured. A comparison was made between intrinsic water and solute permeabilities and the reverse osmosis

H. K. Lonsdale; B. P. Cross; F. M. Graber; C. E. Milstead

1971-01-01

8

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

NASA Technical Reports Server (NTRS)

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.

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

1978-01-01

9

Cellulose membranes for reverse osmosis Part I. RO cellulose acetate membranes including a composite with polypropylene  

Microsoft Academic Search

With the aim of obtaining RO membranes for brackish water desalination from purified celluloses (cotton linters and bleached bagasse pulp), two reactions (heterogeneous and homogeneous) were applied for the synthesis of cellulose acetate (CA). The efficiency of the membranes was measured and compared with those prepared from purchased CA and prepared CA by acetylation of imported high-grade viscose wood pulp.

Houssni El-Saied; Altaf H. Basta; Barsoum N. Barsoum; Mohamed M. Elberry

2003-01-01

10

Electrophoresis  

NSDL National Science Digital Library

Electrophoresis involves the movement of electrically charged substances under the influence of an electric field. This website demonstrates electrophoresis by providing a java applet which virtually applies an electric field across an agarose or polyacrylamide electrophoresis gel in which biological macromolecules are placed. The applet shows how the molecules move and at the end of the experiment plots the logarithm of the molecular weight versus the logarithm of the distance moved. This tutorial is one of a large collection of tutorials on electricity and magnetism available from Molecular Expressions.

Davidson, Michael

2010-12-29

11

Transport Parameters in a Porous Cellulose Acetate Membrane  

PubMed Central

The transport parameters of a cellulose acetate membrane prepared from a mixture of cellulose acetate, formamide, and acetone, 25:25:50 by weight, were studied. The membrane consists of a thin, porous layer, the skin, in series with a thick, highly porous layer, the coarse support. In the skin the diffusional permeability coefficient, ?, of a number of small amides and alcohols depends critically upon the partition coefficient, Ks, the size of the molecule, and the apparent hydrogen-bonding ability, Ns, of the solute. These observations are in general agreement with our earlier conclusions on the properties of nonporous membranes. On the other hand, the corrected reflection coefficient, ?', is not a very sensitive function of either Ns or Ks taken separately. The correlation between ?' and molecular diameter is reasonably good; however, it is much improved when both Ns and Ks are taken into consideration. Isotope interaction was also studied in the present preparation and was found to provide only a small (5–8%) contribution to the diffusional permeability coefficient of ethylene glycol. The contribution of solute-water friction was found to be less than 24% of the total solute friction. PMID:5410490

DiPolo, R.; Sha'afi, R. I.; Solomon, A. K.

1970-01-01

12

Nanoporous layered silicate AMH-3/cellulose acetate nanocomposite membranes for gas separations  

E-print Network

. The exfoliated SAMH-3 flakes were used to form SAMH-3/cellulose acetate (CA) membranes. Their micro- structureNanoporous layered silicate AMH-3/cellulose acetate nanocomposite membranes for gas separations Wun are of interest because they can exploit the high aspect ratio of exfoliated selective flakes/layers to enhance

Nair, Sankar

13

Improved Fixation of Cellulose-Acetate Reverse-Osmosis Membrane for Scanning Electron Microscopy  

PubMed Central

Fixation of cellulose-acetate membranes with either glutaraldehyde-osmium tetroxide or glutaraldehyde-ruthenium tetroxide resulted in extensive electron beam damage. Beam damage was eliminated and the bacterial surface structure was preserved, however, when cellulose-acetate membranes were fixed with glutaraldehyderuthenium tetroxide and treated successively with thiocarbohydrazide and osmium tetroxide. Images PMID:16346735

Kutz, S. M.; Bentley, D. L.; Sinclair, N. A.

1985-01-01

14

A shaking bioreactor equipped with twin ceramic membranes for acetic acid production using Acetobacter pasteurianus  

Microsoft Academic Search

A shaking bioreactor system with twin internal ceramic membranes was developed for effective perfusion culture and applied to the continuous production of acetic acid using Acetobacter pasteurianus. The system makes it possible to carry out the back-washing of the membrane without stopping the continuous operation because one membrane can be washed by medium feed flow while another membrane provides filtration

J. Horiuchi; M. Narumi; K. Tada; M. Kobayashi; T. Kanno; T. Suzuki

2002-01-01

15

Plasma Membrane Vesicles of Opposite Sidedness from Soybean Hypocotyls by Preparative Free-Flow Electrophoresis 1  

PubMed Central

Absolute orientations (sidedness) of plasma membrane vesicles obtained in highly purified fractions by preparative free-flow electrophoresis and by aqueous two-phase partition were determined based on ATPase latency and morphological criteria. Free-flow electrophoresis yielded two plasma membrane fractions. One, the least electronegative and designated fraction `E,' was pure plasma membrane. The other, more electronegative and designated fraction `C,' was heavily contaminated by various other cellular membranes. Plasma membrane vesicles from both fraction C and fraction E partitioned into the upper phase with aqueous two-phase partitioning. Purified plasma membrane obtained from microsomes by two-phase partition (upper phase) when subjected to free-flow electrophoresis also yielded two fractions, one fraction co-migrated with fraction C and another fraction co-migrated with fraction E. Both fractions exhibited an ATPase activity sensitive to vanadate and insensitive to nitrate and azide. ATPase activity was used as a structure-linked latency marker for the inner membrane surface. Concanavalin A binding (linked to peroxidase) was used as an imposed electron microscope marker for the outer membrane surface. Fraction E vesicles showed low ATPase latency (two-fold or less) and weak reactivity with concanavalin A peroxidase. In contrast, fraction C vesicles were characterized by much greater latencies upon detergent treatment (sevenfold) and a strong reaction with concanavalin A peroxidase. Two-phase partition as the initial procedure for plasma membrane isolation, yielded mixtures of vesicles of both inside out and right-side out orientation. Free-flow electrophoresis resolved the plasma membrane isolates into vesicles from fraction C which were right-side out (cytoplasmic side in), and vesicles from fraction E which were wrong-side out (cytoplasmic side out). Therefore, the two methods used in series, provided highly purified membrane preparations of apparently homogenous vesicles of opposite known absolute orientations. Images Fig. 3 Fig. 6 Fig. 7 PMID:16665959

Canut, Hervé; Brightman, Andrew; Boudet, Alain M.; Morré, D. James

1988-01-01

16

Role of membrane surface morphology in colloidal fouling of cellulose acetate and composite aromatic polyamide reverse osmosis membranes  

Microsoft Academic Search

Laboratory-scale colloidal fouling tests, comparing the fouling behavior of cellulose acetate and aromatic polyamide thin-film composite reverse osmosis (RO) membranes, are reported. Fouling of both membranes was studied at identical initial permeation rates so that the effect of the transverse hydrodynamic force (permeation drag) on the fouling of both membranes is comparable. Results showed a significantly higher fouling rate for

Menachem Elimelech; Xiaohua Zhu; Amy E. Childress; Seungkwan Hong

1997-01-01

17

Stabilization of phosphatidylcholine coatings in capillary electrophoresis by increase in membrane rigidity  

Microsoft Academic Search

Divalent cations affect the stability and structure of phospholipid vesicles and also the binding and immobilization of proteins into phospholipid membranes. The effect of calcium, magnesium, and zinc on zwitterionic phosphatidylcholine (PC) coatings in fused silica capillaries for electrophoresis was the primary interest in this work. In addition, the effect of temperature on the coating stability was investigated by coating

Maria V. Lindén; Susanne K. Wiedmer; R. M. Susanna Hakala; Marja-Liisa Riekkola

2004-01-01

18

Chemoreception in Paramecium tetraurelia : acetate and folate-induced membrane hyperpolarization  

Microsoft Academic Search

Acetic and folic acids hyperpolarize the membrane potential ofParamecium tetraurelia in a concentration-dependent manner. The membrane responses are accompanied by small changes in cell resistance, and are significantly reduced by increasing extracellular cation concentrations, suggesting that the attractants bring about the membrane potential change by increasing cell permeability to cations. The inability to show a reversal potential for the hyperpolarization

Robin R. Preston; J. L. Houten

1987-01-01

19

Chelation and permeation of heavy metals using affinity membranes from cellulose acetate–chitosan blends  

Microsoft Academic Search

Affinity membranes have attracted the attention of membrane researchers especially in the field of wastewater treatment specifically in removing heavy metals by chelation from aqueous solutions. In the present work, several membranes are made from either cellulose di-acetate (CA) or CA together with chitosan (CS) solutions, the CS prepared in our lab from shrimp shells or from readymade shrimp or

M. M. Naim; H. E. M. Abdel Razek

2012-01-01

20

Water and ions transport mechanism in hyperfiltration with symmetric cellulose acetate membranes  

Microsoft Academic Search

Hyperfiltration is carried out under reverse osmotic conditions by the application of mechanical energy to force the solvent from higher to lower concentration of solute across semipermeable membranes. In the present investigation, experimental work has been performed to measure the water and inorganic cation transport fluxes across cellulose acetate homogeneous hyperfiltration membranes. The osmosis, reverse osmosis, kinetic conductance and membrane

M. Ashraf Chaudry

2002-01-01

21

Properties of cellulose acetate nanofiltration membranes. Application to brackish water desalination  

Microsoft Academic Search

In this work, we report about cellulose acetate nanofiltration (NF) membrane preparation according to the phase inversion process. Pore size was monitored by using dope solutions of two polymer concentrations (20 and 22 wt?%) and annealing temperatures from 60–80°C. Membrane characterization included a morphologic analysis using scanning electron microscopy (SEM) and hydraulic permeability (Lp0) determined from pure water filtration. SEM

Randa Haddada; Ezzedine Ferjani; Mohamed Sadok Roudesli; André Deratani

2004-01-01

22

Performance of a composite membrane bioreactor for the removal of ethyl acetate from waste air.  

PubMed

Ethyl acetate removal from an air stream was carried out by using a flat composite membrane bioreactor. The composite membrane consisted of a dense polydimethylsiloxane top layer with an average thickness of 0.3 ?m supported in a porous polyacrylonitrile layer (50 ?m). The membrane bioreactor (MBR) was operated during 3 months, and a maximum elimination capacity of 225 g m?³ h?¹ at an empty bed residence time of 60s was observed. Removal efficiencies higher than 95% were obtained for inlet loads lower than 200 g m?³ h?¹ and empty bed residence times as short as 15 s. The estimated yield coefficient, determined from the carbon dioxide production, resulted in 0.82 g dry biomass synthesized per gram of ethyl acetate degraded. No data of ethyl acetate treatment in MBR have been found in the literature, but the results illustrate that membrane bioreactors can potentially be a good option for its treatment. PMID:21763129

Álvarez-Hornos, F J; Volckaert, D; Heynderickx, P M; Van Langenhove, H

2011-10-01

23

Studies on cellulose acetate Polymethylmethacrylate and Polystyrene blend ultrafiltration Membranes;.  

E-print Network

??Membrane separation techniques are being used in various newlineindustries such as chemical pharmaceutical and metal finishing industries newlineThese techniques allow not only energy and cost… (more)

Vidya S

2014-01-01

24

Continuous Ethanol Production with a Membrane Bioreactor at High Acetic Acid Concentrations  

PubMed Central

The release of inhibitory concentrations of acetic acid from lignocellulosic raw materials during hydrolysis is one of the main concerns for 2nd generation ethanol production. The undissociated form of acetic acid can enter the cell by diffusion through the plasma membrane and trigger several toxic effects, such as uncoupling and lowered intracellular pH. The effect of acetic acid on the ethanol production was investigated in continuous cultivations by adding medium containing 2.5 to 20.0 g·L?1 acetic acid at pH 5.0, at a dilution rate of 0.5 h?1. The cultivations were performed at both high (~25 g·L?1) and very high (100–200 g·L?1) yeast concentration by retaining the yeast cells inside the reactor by a cross-flow membrane in a membrane bioreactor. The yeast was able to steadily produce ethanol from 25 g·L?1 sucrose, at volumetric rates of 5–6 g·L?1·h?1 at acetic acid concentrations up to 15.0 g·L?1. However, the yeast continued to produce ethanol also at a concentration of 20 g·L?1 acetic acid but at a declining rate. The study thereby demonstrates the great potential of the membrane bioreactor for improving the robustness of the ethanol production based on lignocellulosic raw materials. PMID:25028956

Ylitervo, Paivi; Franzen, Carl Johan; Taherzadeh, Mohammad J.

2014-01-01

25

Performance of a composite membrane bioreactor for the removal of ethyl acetate from waste air  

Microsoft Academic Search

Ethyl acetate removal from an air stream was carried out by using a flat composite membrane bioreactor. The composite membrane consisted of a dense polydimethylsiloxane top layer with an average thickness of 0.3?m supported in a porous polyacrylonitrile layer (50?m). The membrane bioreactor (MBR) was operated during 3months, and a maximum elimination capacity of 225gm?3h?1 at an empty bed residence

F. J. Álvarez-Hornos; D. Volckaert; P. M. Heynderickx; H. Van Langenhove

2011-01-01

26

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

NASA Technical Reports Server (NTRS)

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.

Wydeven, T.; Leban, M.

1973-01-01

27

Membrane lipid physiology and toxin catabolism underlie ethanol and acetic acid tolerance in Drosophila melanogaster.  

PubMed

Drosophila melanogaster has evolved the ability to tolerate and utilize high levels of ethanol and acetic acid encountered in its rotting-fruit niche. Investigation of this phenomenon has focused on ethanol catabolism, particularly by the enzyme alcohol dehydrogenase. Here we report that survival under ethanol and acetic acid stress in D. melanogaster from high- and low-latitude populations is an integrated consequence of toxin catabolism and alteration of physical properties of cellular membranes by ethanol. Metabolic detoxification contributed to differences in ethanol tolerance between populations and acclimation temperatures via changes in both alcohol dehydrogenase and acetyl-CoA synthetase mRNA expression and enzyme activity. Independent of changes in ethanol catabolism, rapid thermal shifts that change membrane fluidity had dramatic effects on ethanol tolerance. Cold temperature treatments upregulated phospholipid metabolism genes and enhanced acetic acid tolerance, consistent with the predicted effects of restoring membrane fluidity. Phospholipase D was expressed at high levels in all treatments that conferred enhanced ethanol tolerance, suggesting that this lipid-mediated signaling enzyme may enhance tolerance by sequestering ethanol in membranes as phophatidylethanol. These results reveal new candidate genes underlying toxin tolerance and membrane adaptation to temperature in Drosophila and provide insight into how interactions between these phenotypes may underlie the maintenance of latitudinal clines in ethanol tolerance. PMID:16985200

Montooth, Kristi L; Siebenthall, Kyle T; Clark, Andrew G

2006-10-01

28

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

PubMed

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. PMID:24845470

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

2014-07-01

29

Osmotic water transport through cellulose acetate membranes produced from a latex system.  

PubMed

The advisability of a progressive curtailment of organic solvent film coating offers an incentive to develop latex systems. Here, the use of aqueous colloidal dispersions of cellulose acetate, plasticized with water-soluble additives, is proposed as an alternative way to obtain cellulose acetate membranes either by casting or spraying. The osmotic water permeability of both kinds of films was measured, as well as their loss of leachable materials and degree of swelling in a saturated solution of potassium chloride. The permeabilities varied over a wide range depending on the physicochemical properties of the plasticizer and its initial concentration in the latex, and on the conditions for coating (temperature, rate of spraying, and drying duration). High boiling point plasticizers gave more permeable films. Films prepared by casting were found to be sensitive to their sodium dodecyl sulfate content. PMID:3625490

Bindschaedler, C; Gurny, R; Doelker, E

1987-06-01

30

Cellulose acetate hollow fiber ultrafiltration membranes made from CA\\/PVP 360 K\\/NMP\\/water  

Microsoft Academic Search

Hydrophilic hollow fiber ultrafiltration (UF) membranes have been prepared from a new dope solution containing cellulose acetate (CA)\\/poly(vinyl pyrrolidone) (PVP 360K)\\/N-methyl-2-pyrrolidone (NMP)\\/water with a mass ratio of 19.0\\/5.0\\/74.8\\/1.2 by using a dry-jet wet spinning process. The effect of air-gap length was studied. The as-spun fibers were post-treated by means of a hypochlorite solution of 200mgl?1 (200ppm) over different duration. The

Jian-Jun Qin; Ying Li; Leng-Siang Lee; Hsiaowan Lee

2003-01-01

31

Stability of MFI zeolite-filled PDMS membranes during pervaporative ethanol recovery from aqueous mixtures containing acetic acid  

Microsoft Academic Search

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 ethanol mixtures through high-silica ZSM-5 zeolite-filled polydimethylsiloxane (PDMS; silicone rubber) membranes were investigated. Acetic acid was shown to reduce the ethanol removal effectiveness

Travis C. Bowen; Richard G. Meier; Leland M. Vane

2007-01-01

32

Membrane-supported liquid-liquid-liquid microextraction combined with anion-selective exhaustive injection capillary electrophoresis-ultraviolet detection for sensitive analysis of phytohormones.  

PubMed

A novel method based on off-line membrane-supported liquid-liquid-liquid microextraction (MS-LLLME) combined with on-column anion-selective exhaustive injection (ASEI) capillary electrophoresis-ultraviolet (CE-UV) detection was established for the analysis of seven phytohormones (abscisic acid (ABA), jasmonic acid (JA), 2,4-dichlorophenoxyacetic acid (2,4-D), 1-naphthalene acetic acid (NAA), indole-3-acetic acid (IAA), salicylic acid (SA) and gibberellic acid (GA)). In MS-LLLME, the target phytohormones were extracted from the acid donor phase to the alkaline acceptor phase, and the acceptor solutions were directly analyzed by ASEI-CE-UV. Under the optimal experimental conditions, the analytical performance of the method was evaluated. The limits of detection (LODs) of ABA, JA, 2,4-D, NAA, IAA, SA and GA were determined to be 1.00, 2.21, 0.33, 0.17, 0.67, 0.05 and 16.5ng/mL, respectively. The relative standard deviations (RSDs, n=7) ranged from 4.7% to 12.9%, and the enrichment factors were in the range of 307 to 20,160. The proposed method was successfully applied for the determination of multiple phytohormones in banana, cabbage and cucumber extracts, and ABA, IAA and SA were detected in these samples. The recoveries for the spiked samples were in the range of 79.0 to 116.4%. The proposed method was demonstrated to be suitable for the simultaneous quantification of multiple phytohormones with high sensitivity and good sample cleanup ability. PMID:24720904

Huang, Linfang; He, Man; Chen, Beibei; Hu, Bin

2014-05-23

33

Net Increase of platelet membrane tyrosine specific-protein kinase activity by phorbol myristate acetate  

SciTech Connect

Tyrosine protein kinase (TPK) activity in rabbit platelets after stimulation by phorbol myristate acetate (PMA) or thrombin was directly estimated by {sup 32}P incorporation from ({gamma}-{sup 32})ATP into synthetic peptide angiotensin II. By PMA-treatment a net increase of TPK activity was obtained, while thrombin acted on the TPK quickly but stimulation was limited within the range attained by the control after lengthy incubation. The responsive TPK to these stimulators was localized mainly in membrane but much less in cytosol. The specific activity of the particulate TPK was low in the sonicate of control ice cold platelets but increased about 6-fold when the platelets were incubated at 37{degree}C. On a brief contact of platelets with PMA at 37{degrees}C the TPK was fully activated and reached a maximum value about 130% of the control. Determination of phosphotyrosine phosphatase in the stimulated platelet sonicate revealed that its participation in the above described increase of {sup 32}P-incorporation was meagre. The quick response suggested a possible role of TPK in the signal transduction through the platelet cell membrane.

Ishihara, Noriko; Sakamoto, Hikaru; Iwama, Minako; Kobayashi, Bonro (Kitasato Univ., Tokyo (Japan))

1990-01-01

34

Light scattering and membrane formation studies on polysulfone solutions in NMP and in mixed solvents of NMP and ethyl acetate  

Microsoft Academic Search

The relationship between the characteristics of the polymer dope solution and the skin formation mechanism as well as the performance of the asymmetric membrane has been investigated. The solution characteristics have been studied on the polysulfone (PSf) dope solution as a function of the concentrations of both polymer and the cosolvent, ethyl acetate (EA), by dynamic light scattering. An anomalous

Jongok Won; Yong Soo Kang; Hyun Chae Park; Un Young Kim

1998-01-01

35

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

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. PMID:25316372

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

2014-10-28

36

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

NASA Astrophysics Data System (ADS)

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.

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

2012-10-01

37

Membrane-bound NADPH dehydrogenase- and ferredoxin: NADP oxidoreductase activity involved in electron transport during acetate oxidation to CO 2 in Desulfobacter postgatei  

Microsoft Academic Search

Desulfobacter postgatei grows on acetate and sulfate as energy source. The oxidation of acetate to 2 CO2 proceeds via the citric acid cycle involving membrane-bound succinate dehydrogenase and membrane-bound malate dehydrogenase. We report here that the organism contains membrane-bound NADPH dehydrogenase and ferredoxin: NADP oxidoreductase for the reoxidation of NADPH and reduced ferredoxin generated during isocitrate- and 2-oxoglutarate oxidation, respectively.

Dieter Möller-Zinkhan; Rudolf K. Thauer

1988-01-01

38

Selective oxidation of ethanol to acetic acid in highly efficient polymer electrolyte membrane-direct ethanol fuel cells  

Microsoft Academic Search

The selective conversion of ethanol into potassium acetate with concomitant production of electrical energy has been achieved in both passive and active direct fuel cells containing platinum-free electrodes and an anion-exchange polymer membrane. The power densities supplied by the passive systems at r.t. can be as high as 55mWcm?2, while the active systems can deliver up to 170mWcm?2 at 80°C.

Claudio Bianchini; Valentina Bambagioni; Jonathan Filippi; Andrea Marchionni; Francesco Vizza; Paolo Bert; Alessandro Tampucci

2009-01-01

39

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

Microsoft Academic Search

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

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

1997-01-01

40

Analysis of nephritogenic antigens in human glomerular basement membrane by two-dimensional gel electrophoresis.  

PubMed

Collagenase digests of GBM were partially purified by column chromatography and analyzed by 2-D gel electrophoresis. Silver staining of 2-D gels showed charge- and size-related heterogeneity of proteins in the 45 to 50 kDa and 25 to 27 kDa regions. These components were transferred to nitrocellulose sheets and reacted with 10 human anti-GBM autoantibodies. Detection of bound anti-GBM autoantibodies to blotted proteins was carried out with peroxidase-labeled goat anti-human IgG and revealed binding predominantly to the cationic (pI 8 to 9.0) 45 to 50 kDa and 25 to 27 kDa components. Positive-staining patterns of blotted proteins were similar with all anti-GBM autoantibodies except that three sera additionally identified neutral (pI 5.5 to 6.5) protein components. One anti-GBM autoantibody, which developed following renal transplantation, lacked reactivity with the most cationic components in the 25 to 27 kDa region. These findings suggest heterogeneity of nephritogenic GBM antigens. The cationic 45 to 50 kDa components were sensitive to reduction, while one neutral 45 to 50 kDa component was resistant; a complex array of 25 to 30 kDa proteins (pI 5.5 to 7.5) were observed by silver staining postreduction. None of the reduced protein components reacted with anti-GBM antibodies, suggesting that epitopes on nephritogenic GBM antigens may be related to disulfide-bonded regions. Although there is variable immunohistochemical reactivity of anti-GBM autoantibodies with the GBM of infant kidneys, 2-D gels of collagenase-digested human infant GBM blotted and reacted with anti-GBM autoantibodies and showed staining patterns similar to that of adult GBM. These studies demonstrate the presence of nephritogenic antigens in the GBM of immature human kidney which are not detectable by immunohistochemical analysis. PMID:2985699

Yoshioka, K; Kleppel, M; Fish, A J

1985-06-01

41

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

Microsoft Academic Search

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 Mg2+-ATPase and pyrophosphatase activities as enzyme markers. The least

Hervé Canut; Sylvie Baudracco; Mireille Cabané; Alain-Michel Boudet; Gérard Marigo

1991-01-01

42

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

PubMed

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 94.34mgg(-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. PMID:25127386

Li, Renjie; Liu, Lifen; Yang, Fenglin

2014-09-15

43

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)...

44

Calibration and field performance of triolein embedded acetate membranes for passive sampling persistent organic pollutants in water.  

PubMed

Triolein embedded cellulose acetate membrane (TECAM) passive samplers provide potentially powerful tool for monitoring time weighted average concentrations (C(TWA)) of trace hydrophobic organic contaminants in water. To study the field performance of TECAM, exchange kinetics of chemicals between water and TECAM were studied at different temperature and water flow rates. Results showed that the uptake rate constant (k(u)) in TECAM was less sensitive to temperature variation than the SPMD and Chemcatcher. The k(u) in TECAM was sensitive to even a slight change of the flow rate, which required the field calibration using performance reference compounds (PRCs). To estimate C(TWA) by TECAM, both empirical model and WBL model were compared in laboratory conditions, and only small differences were observed between the predicted and measured k(u). Field validation was conducted to test the sampler performance alongside spot sampling. A good agreement of water concentration was obtained by the two sampling techniques. PMID:22361054

Tang, Jianfeng; Chen, Shan; Xu, Yiping; Zhong, Wenjue; Ma, Mei; Wang, Zijian

2012-05-01

45

Colorful Electrophoresis  

NSDL National Science Digital Library

In this activity, learners follow step-by-step instructions to build a gel electrophoresis chamber using inexpensive materials from local hardware and electronic stores. Then, learners follow instructions to simulate DNA electrophoresis using food colors from the kitchen pantry.

Utah, University O.

2012-01-01

46

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

PubMed

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(M) . delta) > 2. A slightly higher value of solute rejection is found in Membrane-2. PMID:16499917

Tiwari, A K; Ahmad, Suhail

2006-06-01

47

Mechanism ofin vivo DNA transport into cells by electroporation: electrophoresis across the plasma membrane may not be involved  

Microsoft Academic Search

Background Recently, in vivo gene transfer with electroporation (electro- gene transfer) has emerged as a leading technology for developing nonviral gene therapies and nucleic acid vaccines. The widely hypothesized mechanism is that electroporation induces structural defects in the membrane and provides an electrophoretic force to facilitate DNA crossing the permeabilized membrane. In this study, we have designed a device and

Feng Liu; Steve Heston; Lisa M Shollenberger; Bin Sun; Marlin Mickle; Michael Lovell; Leaf Huang

2006-01-01

48

Adsorption and desorption of a gold–iodide complex onto cellulose acetate membrane coated with polyaniline or polypyrrole: a comparative study  

Microsoft Academic Search

Cellulose acetate membranes (M1) with controlled thickness were coated with an electroconductive polymer, and the resulting\\u000a composites were characterized by SEM, XPS, electrical conductivity, and mechanical measurements. A comparative study of M1\\u000a coated with polyaniline (PANI) or with polypyrrole (PPy) for adsorption and subsequent desorption of a gold–iodide complex\\u000a was performed. The PANI-coated M1 (M2) and that coated with PPy

M. M. Castillo-Ortega; I. Santos-Sauceda; J. C. Encinas; D. E. Rodriguez-Felix; T. del Castillo-Castro; F. Rodriguez-Felix; J. L. Valenzuela-García; L. S. Quiroz-Castillo; P. J. Herrera-Franco

2011-01-01

49

Electrophoresis-enhanced detection of deoxyribonucleic acids on a membrane-based lateral flow strip using avian influenza H5 genetic sequence as the model.  

PubMed

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

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

2014-01-01

50

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

PubMed Central

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

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

2014-01-01

51

Removal of pesticides and other micropollutants with cellulose-acetate, polyamide and ultra-low pressure reverse osmosis membranes  

Microsoft Academic Search

In 1995 several membrane manufacturers started to sell ultra low-pressure reverse osmosis membranes. The specifications of these membranes indicated that they have rejections for dissolved salts comparable to “conventional” composite (polyamide) membranes, while the required feed pressure to realize a specific production capacity is 30–40% less. This article describes the results of a preliminary study on the performance of these

J. A. M. H. Hofman; E. F. Beerendonk; H. C. Folmer; J. C. Kruithof

1997-01-01

52

Cationic detergents enable the separation of membrane proteins of Plasmodium falciparum-infected erythrocytes by 2D gel electrophoresis.  

PubMed

The intraerythrocytic stage of Plasmodium falciparum alters the characteristics of its host cell by exporting selected plasmodial proteins. Although it is clear that the physicochemical and immunobiological properties of the host cell are modulated during parasite development, the involved plasmodial proteins and their mode of action are not completely known. Using cetyltrimethylammonium bromide (CTAB) or benzyldimethyl-n-hexadecylammonium chloride (16-BAC) for the first dimension and SDS for the second dimension, we separated proteins from membranes of human erythrocytes and of erythrocytes infected with the malaria parasite P. falciparum. Protein spots were analyzed by MALDI-TOF/TOF MS and annotated in respective 2D master gels. By using the alternative 2D approach, characteristic host cell membrane proteins and, more importantly, membrane-associated and exported plasmodial proteins were identified that might play a role in parasite-induced host cell modulation. PMID:22539315

Philipp, Stephan; Jakoby, Thomas; Tholey, Andreas; Janssen, Ottmar; Leippe, Matthias; Gelhaus, Christoph

2012-04-01

53

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...

54

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

PubMed Central

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

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

2013-01-01

55

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

PubMed

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

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

2013-01-01

56

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

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 ?L 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. PMID:22098933

Li, Pingjing; Zhang, Xing; Hu, Bin

2011-12-30

57

Gel Electrophoresis  

NSDL National Science Digital Library

This interactive activity from the Dolan DNA Learning Center illustrates the process of gel electrophoresis, in which DNA fragments are separated by size as they migrate at different rates through a gel matrix.

Foundation, Wgbh E.

2007-04-19

58

Gel Electrophoresis  

NSDL National Science Digital Library

In the early days of DNA manipulation, DNA fragments were laboriously separated by gravity. In the 1970s, the powerful tool of DNA gel electrophoresis was developed. This process uses electricity to separate DNA fragments by size as they migrate through a gel matrix. This animation from Cold Spring Harbor Laboratory's Dolan DNA Learning Center presents Gel Electrophoresis through a series of illustrations of the processes involved.

2012-01-20

59

Analysis of electrophoresis performance  

NASA Technical Reports Server (NTRS)

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.

Roberts, G. O.

1984-01-01

60

Serum protein electrophoresis and immunofixation by a semiautomated electrophoresis system.  

PubMed

Semiautomated agarose electrophoresis and immunofixation performed with Hydrasys-Hyrys (Sebia) were compared with conventional, manually performed methods, including cellulose acetate electrophoresis, immunoelectrophoresis, and immunofixation. Reference intervals for agarose electrophoresis with Hydrasys-Hyrys were determined. Within-run imprecision (CV) for fraction quantitation with the semiautomated system was between 1% (albumin) and 4.5% (beta-globulin). Total imprecision (CV) was between 2.7% (albumin) and 7.3% (beta-globulin). Semiautomated agarose electrophoresis showed linear correlation with cellulose acetate electrophoresis. Thirty-four specimens with monoclonal components were analyzed by manual immunoelectrophoresis and immunofixation and by Hydrasys. In one case, a light-chain disease was missed with Hydrasys when the sample was diluted 1:3 (the routine dilution) but not when the sample was assayed undiluted. In another case, the Hydrasys system revealed a small IgGA monoclonal component in addition to the IgA monoclonal component detected by the manual methods. In the other cases, no differences between the manual methods and the semiautomated method were seen with respect to paraprotein identification. PMID:9590366

Bossuyt, X; Bogaerts, A; Schiettekatte, G; Blanckaert, N

1998-05-01

61

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

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

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

62

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)

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.

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

63

Simulating Electrophoresis.  

ERIC Educational Resources Information Center

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)

Moertel, Cheryl; Frutiger, Bruce

1996-01-01

64

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  

Microsoft Academic Search

The analytical determination of atmospheric pollutants still presents challenges due to the low-level concentrations (frequently in the ?gm?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

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

2010-01-01

65

Characterization of the platelet membrane glycoprotein abnormalities in Bernard-Soulier syndrome and comparison with normal by surface-labeling techniques and high-resolution two-dimensional gel electrophoresis.  

PubMed Central

The platelets from three patients with Bernard-Soulier syndrome have been analyzed by surface-labeling coupled with two-dimensional gel electrophoresis and compared with normals. As well as the previously described absence or deficiency in glycoprotein (GP) Ib(alpha) it could be shown that GP Ib beta and an additional low molecular weight glycoprotein GP17 were not detectable using carbohydrate-labeling methods or deficient to the same extent as the GPIb alpha subunit. In addition, the thrombin cleavable glycoprotein could not be detected using carbohydrate-labeling methods in two patients and was deficient in a third. This finding was confirmed in a fourth patient by one-dimensional gel electrophoresis. Thus, the changes in the membrane of Bernard-Soulier platelets are more complex than previously thought. Images PMID:6284798

Clemetson, K J; McGregor, J L; James, E; Dechavanne, M; Lüscher, E F

1982-01-01

66

Fluid flow electrophoresis in space  

NASA Technical Reports Server (NTRS)

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.

Griffin, R. N.

1975-01-01

67

Serum globulin electrophoresis  

MedlinePLUS

... levels of proteins called globulins in the fluid (serum) part of a blood sample. Other electrophoresis tests that measure proteins in the serum include: Immunoelectrophoresis Immunfixation Protein electrophoresis

68

Agarose gel electrophoresis Solutions and reagents  

E-print Network

to 1L Adjust pH to 8.3 with NaOH or acetic acid Store at RT TBE (5X) Tris 54g EDTA 4.65g Boric Acid 24g ddH2O up to 1L Adjust pH to 8.3 with boric acid Store at RT - Ethidium bromide (EtBr), 10 mg/ml (20) -Electrophoresis buffer: TAE buffer (Tris, acetate, EDTA) 50X, 1L Tris 242g Acetic acid 57,1ml EDTA 100ml ddH2O up

Abou Elela, Sherif

69

5,6-Dimethylxanthenone-4-acetic Acid (DMXAA) Activates Stimulator of Interferon Gene (STING)-dependent Innate Immune Pathways and Is Regulated by Mitochondrial Membrane Potential*  

PubMed Central

The chemotherapeutic agent 5,6-dimethylxanthenone-4-acetic acid (DMXAA) is a potent inducer of type I IFNs and other cytokines. This ability is essential for its chemotherapeutic benefit in a mouse cancer model and suggests that it might also be useful as an antiviral agent. However, the mechanism underlying DMXAA-induced type I IFNs, including the host proteins involved, remains unclear. Recently, it was reported that the antioxidant N-acetylcysteine (NAC) decreased DMXAA-induced TNF-? and IL-6, suggesting that oxidative stress may play a role. The goal of this study was to identify host proteins involved in DMXAA-dependent signaling and determine how antioxidants modulate this response. We found that expression of IFN-? in response to DMXAA in mouse macrophages requires the mitochondrial and endoplasmic reticulum resident protein STING. Addition of the antioxidant diphenylene iodonium (DPI) diminished DMXAA-induced IFN-?, but this decrease was independent of both the NADPH oxidase, Nox2, and de novo generation of reactive oxygen species. Additionally, IFN-? up-regulation by DMXAA was inhibited by agents that target the mitochondrial electron transport chain and, conversely, loss of mitochondrial membrane potential correlated with diminished innate immune signaling in response to DMXAA. Up-regulation of Ifnb1 gene expression mediated by cyclic dinucleotides was also impaired by DPI, whereas up-regulation of Ifnb1 mRNA due to cytosolic double-stranded DNA was not. Although both stimuli signal through STING, cyclic dinucleotides interact directly with STING, suggesting that recognition of DMXAA by STING may also be mediated by direct interaction. PMID:23027866

Prantner, Daniel; Perkins, Darren J.; Lai, Wendy; Williams, Mark S.; Sharma, Shruti; Fitzgerald, Katherine A.; Vogel, Stefanie N.

2012-01-01

70

Kidney cell electrophoresis  

NASA Technical Reports Server (NTRS)

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.

Todd, P.

1980-01-01

71

Kidney cell electrophoresis  

NASA Technical Reports Server (NTRS)

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.

Todd, P.

1979-01-01

72

Capillary Electrophoresis of Proteins  

Microsoft Academic Search

1.1. Capillary Electrophoresis of Proteins Capillary electrophoresis (CE) is a separation technique that combines aspects of both gel electrophoresis and high performance liquid chromatography (HPLC). As is the case for gel electrophoresis, the separation in CE is based upon differential migration in an electrical field. Like HPLC, the detection of the migrating sample analytes may be monitored on-line or postcolumn\\/capillary

Mark Strege

73

Kidney cell electrophoresis  

NASA Technical Reports Server (NTRS)

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.

Todd, P. W.

1985-01-01

74

Identification of plant mitochondrial proteins: A procedure linking two-dimensional gel electrophoresis to protein sequencing from PVDF membranes using a FastBlot cycle  

Microsoft Academic Search

Identification of the 329 spots visible in 2D gels of plant mitochondrial proteins is a challenge. This paper describes a\\u000a 2D mini-gel protocol involving free-radical scavengers and purified reagents to make it compatible with protein sequencing,\\u000a and evaluates its performance. The paper also describes a “FastBlot” sequencing cycle with the cycle time for protein sequencing\\u000a from PVDF membranes reduced to

Bryan Dunbar; Thomas E. Elthon; John C. Osterman; Beth A. Whitaker; S. Brian Wilson

1997-01-01

75

Kidney Cell Electrophoresis  

NASA Technical Reports Server (NTRS)

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.

Todd, P.

1985-01-01

76

Electrophoresis of biological materials  

NASA Technical Reports Server (NTRS)

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.

1975-01-01

77

ProteinAnalysis Electrophoresis  

E-print Network

ProteinDetectionKit(Colorimetric)--GLYCO-PRO GoldSolution,Colloidal--50755 OilRedO--O9755 PonceauSSolution--P7170 ProteoSilverTM--PROT-SIL1 ProteoSilver (G 1041). #12;ProteinAnalysis Electrophoresis sigma-aldrich.com 104 ELECTROPHORESIS Silver Stain Markers Designed for molecular weight determinations on silver stained gels, Silver Stain SDS

Lebendiker, Mario

78

Automatic multiple applicator electrophoresis  

NASA Technical Reports Server (NTRS)

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.

Grunbaum, B. W.

1977-01-01

79

DESOXYCORTICOSTERONE ACETATE  

PubMed Central

1. Desoxycorticosterone acetate (DCA) and NaCl, in the dosage employed in normal rats, caused renal and cardiac hypertrophy, characteristic changes in the renal tubular epithelium, atrophic changes in the subcapsular zone of the adrenal cortex, and serum electrolyte changes characterized by a rise in sodium and fall in potassium. 2. In rats rendered nephritic with a rabbit anti-rat-kidney serum, the same regimen caused similar changes. In addition, DCA given concurrently with NaCl greatly intensified the nephritic process and gave rise to striking arterial hypertension. 3. A diet, virtually sodium-free, administered to normal and nephritic rats receiving daily injections of DCA abolished or reduced to a minimum the effects of this steroid; i.e., a liberal ingestion of NaCl was essential for the potentiation of the action of DCA. 4. The addition of KCl to the drinking water of rats receiving DCA and NaCl tended to correct the depression of the level of potassium in the serum, but had no effect upon the hypertension in nephritic animals nor upon the anatomical lesions. 5. The mechanism by which the sodium ion potentiates the activity of DCA has not been established. PMID:19871607

Knowlton, Abbie I.; Loeb, Emily N.; Stoerk, Herbert C.; Seegal, Beatrice C.

1947-01-01

80

Binary Oscillatory Crossflow Electrophoresis  

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

81

Automatic multiple-sample applicator and electrophoresis apparatus  

NASA Technical Reports Server (NTRS)

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.

Grunbaum, B. W. (inventor)

1977-01-01

82

Electrophoresis experiments in microgravity  

NASA Technical Reports Server (NTRS)

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.

Snyder, Robert S.; Rhodes, Percy H.

1991-01-01

83

Study of Mass Transfer in Membrane Processes.  

National Technical Information Service (NTIS)

Electrical potential differences across membranes were measured with both an anion-exchange membrane used in electrodialysis and a modified cellulose acetate membrane used in reverse osmosis. These measurements were performed in special apparatus which on...

K. S. Spiegler

1970-01-01

84

Multiplexed capillary electrophoresis system  

DOEpatents

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.

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

1996-12-10

85

Multiplexed capillary electrophoresis system  

DOEpatents

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.

Yeung, Edward S. (Ames, IA); Li, Qingbo (Ames, IA); Lu, Xiandan (Ames, IA)

1998-04-21

86

Multiplexed capillary electrophoresis system  

DOEpatents

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.

Yeung, Edward S. (Ames, IA); Chang, Huan-Tsang (Silver Spring, MD); Fung, Eliza N. (Ames, IA); Li, Qingbo (Ames, IA); Lu, Xiandan (Ames, IA)

1996-12-10

87

Multiplexed capillary electrophoresis system  

DOEpatents

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.

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

1998-04-21

88

Detection of Polymorphisms of Human DNA by Gel Electrophoresis as Single-Strand Conformation Polymorphisms  

Microsoft Academic Search

We developed mobility shift analysis of single-stranded DNAs on neutral polyacrylamide gel electrophoresis to detect DNA polymorphisms. This method follows digestion of genomic DNA with restriction endonucleases, denaturation in alkaline solution, and electrophoresis on a neutral polyacrylamide gel. After transfer to a nylon membrane, the mobility shift due to a nucleotide substitution of a single-stranded DNA fragment could be detected

Masato Orita; Hiroyuki Iwahana; Hiroshi Kanazawa; Kenshi Hayashi; Takao Sekiya

1989-01-01

89

Possibility of Microchip Electrophoresis for Biological Application  

NASA Astrophysics Data System (ADS)

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. Nucleic acid fragments are separated by capillary electrophoresis in a chip with microfabricated channels, with automated detection as well as on-line data evaluation. Microfabricated devices are forecast to be fundamental to the postgenome era, especially in the field of genetics and medicine. However, although there are many reports of the use of these instruments to evaluate standard DNA, DNA ladders, PCR products, and commercially available plasmid digests, little information is available their use with biological material. In this report, we showed the accuracy of sizing and quantification of endonuclease-digested plasmid DNA. We also showed the feasibility of on-microchip endonuclease treatment of plasmid DNA and sequential analysis as an additional application for DNA analysis. Furthermore, to evaluate the possibility of microchip electrophoresis for biological application, the results of the examination of blood sugar in human plasma and mitochondrial membrane potential were shown.

Kataoka, Masatoshi; Kido, Jun-Ichi; Shinohara, Yasuo

90

A Specialized Citric Acid Cycle Requiring Succinyl-Coenzyme A (CoA):Acetate CoA-Transferase (AarC) Confers Acetic Acid Resistance on the Acidophile Acetobacter aceti  

Microsoft Academic Search

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

Elwood A. Mullins; Julie A. Francois; T. Joseph Kappock

2008-01-01

91

[Serum protein electrophoresis: comparison of capillary zone electrophoresis Capillarys (Sebia) and agarose gel electrophoresis Hydrasys (Sebia)].  

PubMed

Since several years, serum proteins electrophoresis became a routine analysis, mainly performed by agarose gel electrophoresis, frequently semi-automated. We compared the new fully automated capillary electrophoresis system from Sebia, Capillarys, with our reference method, agarose gel electrophoresis Hydrasys (Sebia). This study focused on the evaluation of both the analytical performances and some practical aspects such as ease of use, rapidity, costs. It appears clearly from that study that both methods give similar results for the detection of monoclonal proteins. We notice that the capillary electrophoresis (Capillarys) displays higher sensitivity (97.2%) than the agarose gel electrophoresis Hydrasys (93.5%), however with a lower specificity (93.7 versus 98.9%). On the other hand, the Capillarys method displays obvious practical advantages such as full automation, ease of use and rapidity. PMID:14671753

Lissoir, B; Wallemacq, P; Maisin, D

2003-01-01

92

Quantification of Fumaria officinalis isoquinoline alkaloids by nonaqueous capillary electrophoresis–electrospray ion trap mass spectrometry  

Microsoft Academic Search

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

Sonja Sturm; Eva-Maria Strasser; Hermann Stuppner

2006-01-01

93

Serum and urine electrophoresis for detection and identification of monoclonal proteins.  

PubMed

Electrophoresis may be defined as the separation of charged particles in a uniform electric field. For a particular system of electrophoresis, the voltage is held constant as are the pH and ionic strength of the suspending medium. Tiselius, using a moving boundary liquid system, separated serum proteins by electrophoresis into four components in 1937. Paper electrophoresis, popular in the 1950s, provided the rst solid electrophoresis support. The fragility of paper as a support medium saw the introduction of the more robust cellulose acetate a decade later. An improvement in resolution was subsequently gained by using agarose gel, which, in serum samples, gave 5 bands of separation. In the late 1980s, high resolution agarose gels were introduced which produced at least 6 bands, and depending on the system, as many as 17 bands in serum. Fully automated serum electrophoresis commenced in the 1990s with the introduction of capillary electrophoresis (CE), a reintroduction of a liquid medium but with exquisite resolution compared to Tiselius' procedure. Using CE instrumentation it is possible to program a sequence of samples and leave them overnight to be processed.Amalgamation of laboratories with an increasing number of patient samples was probably the reason for the semi-automation of gel electrophoresis. The introduction of the Helena SPIFE and Sebia Hydrasys gel systems provided ways of electrophoresing over a hundred serum samples per day. There is certainly a role for such instrumentation in electrophoresis laboratories today. PMID:19841694

Jenkins, Margaret A

2009-08-01

94

Serum and Urine Electrophoresis for Detection and Identification of Monoclonal Proteins  

PubMed Central

Electrophoresis may be defined as the separation of charged particles in a uniform electric field. For a particular system of electrophoresis, the voltage is held constant as are the pH and ionic strength of the suspending medium. Tiselius, using a moving boundary liquid system, separated serum proteins by electrophoresis into four components in 1937.1 Paper electrophoresis, popular in the 1950s, provided the rst solid electrophoresis support. The fragility of paper as a support medium saw the introduction of the more robust cellulose acetate a decade later. An improvement in resolution was subsequently gained by using agarose gel, which, in serum samples, gave 5 bands of separation.2,3 In the late 1980s, high resolution agarose gels were introduced which produced at least 6 bands, and depending on the system, as many as 17 bands in serum.4,5 Fully automated serum electrophoresis commenced in the 1990s with the introduction of capillary electrophoresis (CE), a reintroduction of a liquid medium but with exquisite resolution compared to Tiselius’ procedure. Using CE instrumentation it is possible to program a sequence of samples and leave them overnight to be processed. Amalgamation of laboratories with an increasing number of patient samples was probably the reason for the semi-automation of gel electrophoresis. The introduction of the Helena SPIFE and Sebia Hydrasys gel systems provided ways of electrophoresing over a hundred serum samples per day. There is certainly a role for such instrumentation in electrophoresis laboratories today. PMID:19841694

Jenkins, Margaret A.

2009-01-01

95

Capillary electrophoresis in clinical chemistry  

Microsoft Academic Search

Since its introduction, capillary electrophoresis has diversified, spreading out into different specialized fields covering solutions for almost any analytical questions arising in research laboratories. In the context of clinical chemistry, results must be provided at low costs and in a clinically relevent time frame; however, the attributes which have made capillary electrophoresis such a successful tool in basic research are

Rainer Lehmann; Wolfgang Voelter; Hartmut M. Liebich

1997-01-01

96

Binary Oscillatory Crossflow Electrophoresis  

NASA Technical Reports Server (NTRS)

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 solute is drawn into the cell from reservoirs at both ends of the cell leading to a large mass build up. As a consequence, any initially induced mass flux will vanish after short times. This effect was not captured by the infinite channel model and hence numerical and experimental results deviated significantly. The revised model including finite cell lengths and reservoir volumes allowed quantitative predictions of the time history of the concentration profile throughout the system. This latter model accurately describes the fluxes observed for both oscillatory flow modes in experiments using single protein species. Based on the results obtained from research funded under NASA grant NAG-8-1080.S, we conclude that binary separations are not possible using purely oscillatory flow modes because of end effects associated with the cos((omega)t) mode. Our research shows, however, that a combination of cos(2(omega)t) and steady flow should lead to efficient separation free of end effects. This possibility is currently under investigation.

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

1997-01-01

97

Association for Biology Laboratory Education (ABLE) ~ http://www.zoo.utoronto.ca/able Demystifying Hardy-Weinberg: Using Cellulose Acetate  

E-print Network

Demystifying Hardy-Weinberg: Using Cellulose Acetate Electrophoresis of the Lap Locus to Study Population From: Peroni, P. A. and D. E. McCauley. 1999. Demystifying Hardy-Weinberg: Using cellulose acetate................................................................114 Appendix B: Calculation of Allele and Genotype Frequencies and Hardy-Weinberg Review

98

Capillary electrophoresis of gene mutation.  

PubMed

This chapter illustrates the usefulness of capillary electrophoresis (CE) for the detection of gene mutation, i.e., point mutation, methylation, and microsatellite analysis. In order to provide a general description of the main results and challenges in the field, some relevant applications and reviews on CE of gene mutation are tabulated. Furthermore, some detailed experimental procedures are shown. Several CE methods of gene mutation detection were developed including the following: (1) single-strand conformation polymorphism with capillary electrophoresis; (2) SNaPshot analysis; (3) constant denaturant capillary electrophoresis; (4) microsatellite analysis; and (5) methylation analysis. PMID:18392579

Xu, Guowang; Shi, Xianzhe; Zhao, Chunxia; Yuan, Kailong; Weng, Qianfeng; Gao, Peng; Tian, Jing

2008-01-01

99

The Acetate Switch  

PubMed Central

To succeed, many cells must alternate between life-styles that permit rapid growth in the presence of abundant nutrients and ones that enhance survival in the absence of those nutrients. One such change in life-style, the “acetate switch,” occurs as cells deplete their environment of acetate-producing carbon sources and begin to rely on their ability to scavenge for acetate. This review explains why, when, and how cells excrete or dissimilate acetate. The central components of the “switch” (phosphotransacetylase [PTA], acetate kinase [ACK], and AMP-forming acetyl coenzyme A synthetase [AMP-ACS]) and the behavior of cells that lack these components are introduced. Acetyl phosphate (acetyl?P), the high-energy intermediate of acetate dissimilation, is discussed, and conditions that influence its intracellular concentration are described. Evidence is provided that acetyl?P influences cellular processes from organelle biogenesis to cell cycle regulation and from biofilm development to pathogenesis. The merits of each mechanism proposed to explain the interaction of acetyl?P with two-component signal transduction pathways are addressed. A short list of enzymes that generate acetyl?P by PTA-ACKA-independent mechanisms is introduced and discussed briefly. Attention is then directed to the mechanisms used by cells to “flip the switch,” the induction and activation of the acetate-scavenging AMP-ACS. First, evidence is presented that nucleoid proteins orchestrate a progression of distinct nucleoprotein complexes to ensure proper transcription of its gene. Next, the way in which cells regulate AMP-ACS activity through reversible acetylation is described. Finally, the “acetate switch” as it exists in selected eubacteria, archaea, and eukaryotes, including humans, is described. PMID:15755952

Wolfe, Alan J.

2005-01-01

100

Rapid Simultaneous Determination of Organic Acids, Free Amino Acids, and Lactose in Cheese by Capillary Electrophoresis  

Microsoft Academic Search

A capillary electrophoresis (CE) method for the si- multaneous separation of 11 metabolically important organic acids (oxalic, formic, citric, succinic, orotic, uric, acetic, pyruvic, propionic, lactic, and butyric), 10 amino acids (Asp, Glu, Tyr, Gly, Ala, Ser, Leu, Phe, Lys, and Trp), and lactose has been optimized, validated, and tested in dairy products. Repeatability and linearity were calculatedfor eachcompound, withdetection

J. M. Izco; M. Tormo; R. Jiménez-Flores

2002-01-01

101

Copolymers For Capillary Gel Electrophoresis  

DOEpatents

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.

Liu, Changsheng (State College, PA); Li, Qingbo (State College, PA)

2005-08-09

102

Electrophoresis for Under Five Dollars.  

ERIC Educational Resources Information Center

Equipped with a little more than batteries, food-dye, and sieving media, teachers can demonstrate an essential process used in biochemical research. An activity is provided to aid in helping students to understand electrophoresis. (ZWH)

Lumetta, Vincent J.; Doktycz, Mitchel J.

1994-01-01

103

DNA typing by capillary electrophoresis  

SciTech Connect

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.

Zhang, N.

1997-10-08

104

Rapid analysis of atorvastatin calcium using capillary electrophoresis and microchip electrophoresis.  

PubMed

In this work, a capillary electrophoretic method for the rapid quantitation of atorvastatin (AT) in a lipitor tablet was investigated and developed. Method development included studies of the effect of applied potential, buffer concentration, buffer pH, and hydrodynamic injection time on the electrophoretic separation. The method was validated with regard to linearity, precision, specificity, LOD, and LOQ. The optimum electrophoretic separation conditions were 25 mM sodium acetate buffer at pH 6, with a separation voltage of 25 kV using a 50 microm capillary of 33 cm total length. Sodium diclofenac was used as an internal standard. Analysis of AT in a commercial lipitor tablet by electrophoresis gave quite high efficiency, coupled with an analysis time of less than 1.2 min in comparison to LC. Once the separation was optimized on capillary, it was further miniaturized to a microchip platform, with linear imaging UV detection using microchip electrophoresis (MCE). Linear imaging UV detection allowed for real-time monitoring of the analyte movement on chip, so that the optimum separation time could be easily determined. This microchip electrophoretic method was compared to the CE method with regard to speed, efficiency, precision, and LOD. This work represents the most rapid and first reported analysis of AT using MCE. PMID:16786480

Guihen, Elizabeth; Sisk, Garry D; Scully, Norma M; Glennon, Jeremy D

2006-06-01

105

Electrophoresis experiment, experiment MA-014  

NASA Technical Reports Server (NTRS)

A continuous, free flow electrophoresis study was conducted during the Apollo Soyuz Test Project mission to investigate and evaluate the increase in sample flow rate and sample resolution achievable in space. The electrophoresis equipment was designed for the separation of four mixtures of biological cells with variable sample flow rates, buffer flow rates, and electric field gradients. Separation quality was assessed by measuring the light from a quartz lamp through the electrophoresis channel and on to a photodiode system. The preliminary results indicate that all monitored systems operated correctly during the experiment. The optical system produced a light that was too bright to discern true cell distributions, but data were received that show a distribution of separated cells.

Hannig, K.; Wirth, H.

1976-01-01

106

Acetobacter aceti Possesses a Proton Motive Force-Dependent Efflux System for Acetic Acid  

PubMed Central

Acetic acid bacteria are obligate aerobes able to oxidize ethanol, sugar alcohols, and sugars into their corresponding acids. Among them, Acetobacter and Gluconacetobacter species have very high ethanol oxidation capacity, leading to accumulation of vast amounts of acetic acid outside the cell. Since these bacteria are able to grow in media with high concentrations of acetic acid, they must possess a specific mechanism such as an efflux pump by which they can resist the toxic effects of acetic acid. In this study, the efflux pump of Acetobacter aceti IFO 3283 was examined using intact cells and membrane vesicles. The accumulation of acetic acid/acetate in intact cells was increased by the addition of a proton uncoupler and/or cyanide, suggesting the presence of an energy-dependent efflux system. To confirm this, right-side-out and inside-out membrane vesicles were prepared from A. aceti IFO 3283, and the accumulation of acetic acid/acetate in the vesicles was examined. Upon the addition of a respiratory substrate, the accumulation of acetic acid/acetate in the right-side-out vesicles was largely decreased, while its accumulation was very much increased in the inside-out vesicles. These respiration-dependent phenomena observed in both types of membrane vesicles were all sensitive to a proton uncoupler. Acetic acid/acetate uptake in the inside-out membrane vesicles was dependent not on ATP but on the proton motive force. Furthermore, uptake was shown to be rather specific for acetic acid and to be pH dependent, because higher uptake was observed at lower pH. Thus, A. aceti IFO 3283 possesses a proton motive force-dependent efflux pump for acetic acid. PMID:15968043

Matsushita, Kazunobu; Inoue, Taketo; Adachi, Osao; Toyama, Hirohide

2005-01-01

107

Contactless conductivity detector for microchip capillary electrophoresis.  

PubMed

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. PMID:12033293

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

2002-05-01

108

Acidbase interaction in the acetic acid-acetic anhydride system  

Microsoft Academic Search

1.The electroconductivity and dielectric permeability of the acetic acid-acetic anhydride system have been measured. The electroconductivity of the system has a maximum close to 50% of the anhydride. The curve of the dielectric permeability is concave toward the composition axis.2.The dependence of the electroconductivity on the composition is explained by the formation of a complex between acetic acid and acetic

V. E. Bel'skii; M. I. Vinnik

1963-01-01

109

Gel Electrophoresis Lab: DNA Fingerprinting  

NSDL National Science Digital Library

This lab activity from the Biotechnology Alliance for Suncoast Biology Educators introduces the methods of RFLP analysis, or DNA fingerprinting, by using gel electrophoresis. Students will learn the role of restriction enzymes in DNA fingerprinting. Required materials, procedure and instructions are provided. This lesson plan may be downloaded in Microsoft Word document file format.

Ehlers, Megan

2012-10-24

110

Gel Electrophoresis Lab: Paternity Case  

NSDL National Science Digital Library

This lab activity from the Biotechnology Alliance for Suncoast Biology Educators provides instructions for conducting a gel electrophoresis lab. Students will try to solve a paternity case with this activity by obtaining a DNA fingerprint from each potential father, the mother and the child. This activity may be downloaded in PDF file format. A data collection sheet and student questions are also included.

2013-07-05

111

The Solvent Properties of Water in Desalination Membranes  

Microsoft Academic Search

The solvent properties of water in regular copolyoxamide and cellulose acetate membranes have been investigated. Partition coefficients of chlorides between the water in dense cellulose acetate membranes and a bulk aqueous phase decreased in the order: Cs > K > Na > Li > Ca > Mg. In copolyoxamide membranes, partition coefficients of both chlorides and nitrates showed similar trends.

Philippa M. Wiggins; René T. Van Ryn

1986-01-01

112

DNA electrophoresis in a monodisperse porous medium  

Microsoft Academic Search

Electrophoresis of DNA migrating in an ordered matrix is studied and compared with classical agarose gel electrophoresis. A well-defined migration medium is obtained by crystallization of monodisperse silica spheres. Electrophoretic mobility of DNA is measured with fluorescence recovery after photobleaching experiments. The main result is that, as it was the case for gel electrophoresis, diffusion and electrophoretic mobility of DNA

L. Meistermann; B. Tinland

2000-01-01

113

Mode of Action of the Antibacterial Compound Dequalinium Acetate  

PubMed Central

Dequalinium acetate is taken up rapidly by bacterial cells. Unlike the membrane-active drugs exemplified by cetrimide or chlorhexidine, its capacity for damaging the plasma membrane is low. The drug appears to penetrate quite rapidly into the cytoplasm where its effect seems to be exerted. A review of the evidence obtained in this study suggests that nucleic acid-containing components of the cell may be the prime target of this compound. PMID:4975451

Hugo, W. B.; Frier, M.

1969-01-01

114

Proteome analysis of Acetobacter pasteurianus during acetic acid fermentation.  

PubMed

Acetic acid bacteria (AAB) are Gram-negative, strictly aerobic microorganisms that show a unique resistance to ethanol (EtOH) and acetic acid (AcH). Members of the Acetobacter and Gluconacetobacter genera are capable of transforming EtOH into AcH via the alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) enzymes and are used for the industrial production of vinegar. Several mechanisms have been proposed to explain how AAB resist high concentrations of AcH, such as the assimilation of acetate through the tricarboxylic acid (TCA) cycle, the export of acetate by various transporters and modifications of the outer membrane. However, except for a few acetate-specific proteins, little is known about the global proteome responses to AcH. In this study, we used 2D-DIGE to compare the proteome of Acetobacter pasteurianus LMG 1262(T) when growing in glucose or ethanol and in the presence of acetic acid. Interesting protein spots were selected using the ANOVA p-value of 0.05 as threshold and 1.5-fold as the minimal level of differential expression, and a total of 53 proteins were successfully identified. Additionally, the size of AAB was reduced by approximately 30% in length as a consequence of the acidity. A modification in the membrane polysaccharides was also revealed by PATAg specific staining. PMID:22155126

Andrés-Barrao, Cristina; Saad, Maged M; Chappuis, Marie-Louise; Boffa, Mauro; Perret, Xavier; Ortega Pérez, Ruben; Barja, François

2012-03-16

115

Genetic distances in the tribe Bovini studied by gel electrophoresis  

E-print Network

volts 7 applications end load ice in tank DIA4 cello gel ENO1 cellulose acetate 0. 10 M Trizma base 0. 05 M Boric acid pH 8. 2 0. 10 M Trizma base 0, 10 M Maleic anhydride 0. 01 M MgC12. 6H20 pH 7. 4 (*membrane buffer- I:3 dilution) 2... hours 100 volts 2-5 applications middle load room temperature 45 minutes 150 volts 1-3 applications end load ice in tank ESD cellulose acetate 0. 90 M Trizma base 0. 019 M Na4EDTA 0. 50 M Boric acid pH 8. 6 (*membrane and tank buffers-1...

Butts, Kelley Elaine McRae

2012-06-07

116

The clinical use of PET with 11C-acetate  

PubMed Central

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

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

2012-01-01

117

MACROPHAGE PLASMA MEMBRANES  

PubMed Central

Plasma membranes have been isolated from pure populations of rabbit alveolar macrophages which were swollen in water, fixed briefly with glutaraldehyde, disrupted by Dounce homogenization, and separated by sucrose gradient centrifugation. The recovered membranes exhibited good structural preservation and enzymatic activity; both morphologic and biochemical evidence indicated a high degree of purity (>90%) of the membrane preparation. Interiorized plasma membranes were also prepared without exposure to glutaraldehyde from phagocytic vacuoles recovered from alveolar macrophages which had ingested large numbers of polystyrene spheres. These membranes were contaminated with lysosomal constituents, but they were nevertheless of value for comparison to the "pure" membranes isolated by the glutaraldehyde procedure. Acrylamide gel electrophoresis of the solubilized plasma membranes and phagolysosomal membranes revealed similar protein patterns, with seven to nine individual components ranging in molecular weight from 70,000 to 140,000. The two most rapidly migrating components gave positive reactions for lipid as well as protein. A band containing carbohydrate was detected near the origin of the plasma membrane gels. Antisera were made by injecting guinea pigs with the purified rabbit alveolar macrophage plasma membranes. Gel diffusion and immunoelectrophoretic study of these antisera established the presence of rabbit immunoglobulin G and of one or two other antigenic constituents in the membrane preparation. PMID:4323071

Nachman, Ralph L.; Ferris, Barbara; Hirsch, James G.

1971-01-01

118

Separation of Lanthanides and Quantification of Hydronium ION by Capillary Zone Electrophoresis  

Microsoft Academic Search

The effects of acetate (Ac) concentration on the separation of lanthanides from hydronium ion (H3O) in capillary zone electrophoresis is investigated. The effects of sample acidity and buffers on the H3O peak have been studied. A mixture of 14 rare earth metals, along with H3O, can be baseline separated in less than nine minutes by use of a ternary buffer

Y. Zhang; S. A. Shamsi; M. Sánchez Peña; S. Thibodeaux; I. M. Warner

1996-01-01

119

Membranes and Films from Polymers.  

ERIC Educational Resources Information Center

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)

Blumberg, Avrom A.

1986-01-01

120

Integrated multiplexed capillary electrophoresis system  

DOEpatents

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.

Yeung, Edward S. (Ames, IA); Tan, Hongdong (Ames, IA)

2002-05-14

121

Development of a New Concept in Membrane Structure for Application in Hemodialysis.  

National Technical Information Service (NTIS)

The objective of this program was to develop ultrathin membranes that would exhibit superior transport properties when compared to conventional cellulose membranes. A new, high permeability ultrathin cellulose membrane derived from cellulose acetate has b...

L. T. Rozelle, R. J. Petersen

1974-01-01

122

Capillary electrophoresis for drug analysis  

NASA Astrophysics Data System (ADS)

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.

Lurie, Ira S.

1999-02-01

123

Biotechnology Curriculum Freshman Exploratory: Electrophoresis  

NSDL National Science Digital Library

Gel electrophoresis is used in many areas of biotechnology and forensics. It is based on the concept that mixtures of substances can be separated by electrical force. The direction and speed of migration through the field is dependent on several factors. All substances are made of molecules that can be positively charged, negatively charged or neutral. These characteristics can be used to separate molecules when they are placed in a gel that has an electrical field. The gels generally used are made of agarose, a purified version of agar used in making bacterial plates. These gels are a porous material that acts as a molecular sieve through which smaller molecules can move more easily than larger ones. They move toward the opposite charged side of the gel with smaller pieces of DNA moving farther from the well compared to larger pieces. In this activity, students will identify separate molecules in a mixture by exposing them to an electric field, determine the charge and size of a molecule by its movement in a gel, and explain the importance of electrophoresis as a tool in biotechnology. This activity may be downloaded in Microsoft Word Doc file format.

Kurtz, Mary J.

2013-08-06

124

Acetic Acid Catalyzed Carbon Aerogels  

Microsoft Academic Search

We prepared carbon aerogels with a wide range of structural properties and densities using the weak acetic acid as a catalyst. Two series of acetic acid catalyzed carbon aerogels with different dilution of the catalyst and the monomers were investigated accurately. Structural investigation was performed via (U)SAXS, gas sorption and SEM. The pore and particle size can be tailored according

R. Brandt; R. Petricevic; H. Pröbstle; J. Fricke

2003-01-01

125

Acetate metabolism in Methanothrix soehngenii  

Microsoft Academic Search

Acetate is quantitatively the most important intermediate in the anaerobic degradation of soluble organic matter. The conversion rate of acetate by methanogenic bacteria is proposed to be the rate limiting step in this degradation The study of acetoclastic methanogens, therefore is of relevance to our understanding of anaerobic processes and their optimal application in treatment of waste water from various

M. S. M. Jetten

1991-01-01

126

Acetic acid bacteria in oenology  

Microsoft Academic Search

Acetic acid bacteria have always been considered the bad mi- croorganisms of oenology; responsible for wine spoiling (vine- gary taint). The taxonomy and our knowledge of the metabo- lism of acetic acid bacteria are rapidly evolving, especially as new molecular biology techniques are applied to this fastidious group of microorganisms, which are still rather difficult to work with. The dramatic

A. Mas; M. J. Torija; A. González; M. Poblet; J. M. Guillamón

127

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

PubMed

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. PMID:10075269

Tjørnelund, J; Hansen, S H

1999-01-29

128

DNA Sequencing Using capillary Electrophoresis  

SciTech Connect

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 application papers of sequencing up to this level were also published in the mid 1990's. A major interest of the sequencing community has always been read length. The longer the sequence read per run the more efficient the process as well as the ability to read repeat sequences. We therefore devoted a great deal of time to studying the factors influencing read length in capillary electrophoresis, including polymer type and molecule weight, capillary column temperature, applied electric field, etc. In our initial optimization, we were able to demonstrate, for the first time, the sequencing of over 1000 bases with 90% accuracy. The run required 80 minutes for separation. Sequencing of 1000 bases per column was next demonstrated on a multiple capillary instrument. Our studies revealed that linear polyacrylamide produced the longest read lengths because the hydrophilic single strand DNA had minimal interaction with the very hydrophilic linear polyacrylamide. Any interaction of the DNA with the polymer would lead to broader peaks and lower read length. Another important parameter was the molecular weight of the linear chains. High molecular weight (> 1 MDA) was important to allow the long single strand DNA to reptate through the entangled polymer matrix. In an important paper, we showed an inverse emulsion method to prepare reproducibility linear polyacrylamide polymer with an average MWT of 9MDa. This approach was used in the polymer for sequencing the human genome. Another critical factor in the successful use of capillary electrophoresis for sequencing was the sample preparation method. In the Sanger sequencing reaction, high concentration of salts and dideoxynucleotide remained. Since the sample was introduced to the capillary column by electrokinetic injection, these salt ions would be favorably injected into the column over the sequencing fragments, thus reducing the signal for longer fragments and hence reading read length. In two papers, we examined the role of individual components from the sequencing reaction and then developed a protocol to reduce the deleterio

Dr. Barry Karger

2011-05-09

129

Molecular Structure of Phenylmercuric acetate  

NSDL National Science Digital Library

Phenylmercuric acetate is white to white-yellow crystalline powder that is odorless. This phenyl mercury compound is used mainly as a fungicide, herbicide, slimicide and bacteriocide. Phenylmercuric acid serves as a preservative in canned paint, eye ointments and drops, injectable solutions, skin disinfectants and in cosmetics products such as hair shampoos, mouthwashes and toothpastes. It is also used in contraceptive gels and foams. Phenylmercuric acetate is prepared by interaction of benzene with mercuric acetate in glacial acetic acid. Phenylmercuric acetate's former production and use as a fungicide and as a mildew inhibitor in paints may have resulted in its direct release to the environment. This substance is very toxic to aquatic organisms and may be hazardous to the environment.

2004-11-10

130

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

SciTech Connect

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.

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

1986-03-05

131

Conductance of Dilute Sodium Acetate Solutions to 469 K and of Acetic Acid and Sodium Acetate\\/Acetic Acid Mixtures to 548 K and 20 MPa  

Microsoft Academic Search

In order to obtain accurate association constants for sodium acetate, a very precise flow method was used to measure the electrical conductivity of dilute aqueous solutions of sodium acetate at ambient conditions and 469 K and 20 MPa. Measurements at ambient conditions, 469 and 548 K and 20 MPa, were also made on sodium acetate\\/acetic acid mixtures and acetic acid.

G. H. Zimmerman; R. H. Wood

2002-01-01

132

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

SciTech Connect

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) Moderate ammonia flux. The advantages of producing acetic acid by fermentation include its appropriateness for small-scale production, lower cost feedstocks, low energy membrane-based purification, and lower temperature and pressure requirements. Potential energy savings of using fermentation are estimated to be approximately 14 trillion Btu by 2020 from a reduction in natural gas use. Decreased transportation needs with regional plants will eliminate approximately 200 million gallons of diesel consumption, for combined savings of 45 trillion Btu. If the fermentation process captures new acetic acid production, savings could include an additional 5 trillion Btu from production and 7 trillion Btu from transportation energy.

Snyder, S. W.; Energy Systems

2010-02-08

133

Electrophoresis-mass spectrometry probe  

DOEpatents

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.

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

1987-11-10

134

Electrophoresis-mass spectrometry probe  

DOEpatents

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.

Andresen, Brian D. (Pleasanton, CA); Fought, Eric R. (Livermore, CA)

1987-01-01

135

Laser Doppler methods in electrophoresis  

NASA Astrophysics Data System (ADS)

Electrophoretic motion of particles, molecules, and biological cells can be readily measured by laser Doppler techniques. Small frequency shifts associated with the motion of the scatterers are detected by heterodyne detection of the scattered laser light. The principles of laser light scattering and heterodyne detection are reviewed. The central experimental problems associated with the application of electric fields to conducting solutions are considered in detail. Various types of laser Doppler spectrometers and electrophoresis chambers are compared both from fundamental physical points of view as well as in terms of resolving power of standard marker cells. As applications of the laser Doppler technique, measurements on proteins, virtues, nucleic acids, bioparticles and biological cells are reviewed.

Uzgiris, Egidijus E.

136

Non-Aqueous Capillary Electrophoresis  

NASA Astrophysics Data System (ADS)

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.

Szumski, Micha?; Buszewski, Bogus?aw

137

Nonlinear waves in capillary electrophoresis  

E-print Network

Electrophoretic separation of a mixture of chemical species is a fundamental technique of great usefulness in biology, health care and forensics. In capillary electrophoresis the sample migrates in a microcapillary in the presence of a background electrolyte. When the ionic concentration of the sample is sufficiently high, the signal is known to exhibit features reminiscent of nonlinear waves including sharp concentration `shocks'.In this paper we consider a simplified model consisting of a single sample ion and a background electrolyte consisting of a single co-ion and a counterion in the absence of any processes that might change the ionization states of the constituents. If the ionic diffusivities are assumed to be the same for all constituents the concentration of sample ion is shown to obey a one dimensional advection diffusion equation with a concentration dependent advection velocity.If the analyte concentration is sufficiently low in a suitable non-dimensional sense, Burgers' equation is recovered, an...

Ghosal, Sandip; 10.1007/s11538-010-9527-2

2012-01-01

138

Getting the Most out of Electrophoresis Units  

ERIC Educational Resources Information Center

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…

Mulvihill, Charlotte

2007-01-01

139

Fluorescence detection for gel and capillary electrophoresis  

SciTech Connect

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.

Hogan, B.

1992-07-21

140

Pre-Cast Gel Electrophoresis Guide  

E-print Network

Novex® Pre-Cast Gel Electrophoresis Guide Version B January 27, 2003 IM-1002 Novex® Pre-Cast Gel Electrophoresis Guide General information and protocols for using Novex® pre-cast gels www.invitrogen.com tech.....................................................................................................................1 Novex® Pre-Cast Gels

Kirschner, Marc W.

141

Selective hydrogenation of cyclopentadiene in a catalytic cellulose acetate hollow-fiber reactor  

Microsoft Academic Search

A catalytic membrane reactor was established with catalytic hollow fibers prepared by supporting polymer anchored palladium catalysts on the inside wall of cellulose acetate hollow fibers. The selective hydrogenation of cyclopentadiene was carried out in the catalytic membrane reactor at 40°C in two ways: (1) by hydrogen permeating into the hollow fibers, and (2) by hydrogen premixed in the gas

Hanrong Gao; Shijian Liao; Yun Xu; Ren Liu; Jing Liu; Decai Li

1994-01-01

142

MEMBRANE SURFACE MODIFICATION AND BACKPULSING FOR WASTEWATER TREATMENT  

Microsoft Academic Search

Using a novel photoinduced grafting method, hydrophobic polypropylene (PP) membranes were rendered hydrophilic by grafting monomers of poly(ethylene glycol 200) monomethacrylate (PEG200MA), dimethyl aminoethyl methacrylate (DMAEMA), or acrylic acid (AA), to produce a neutral, positive, or negative charge, respectively, on the membrane surface. Using both unmodified and modified PP membranes, as well as a hydrophilic cellulose acetate (CA) membrane, the

Huimin Ma; David R. Nielsen; Christopher N. Bowman; Robert H. Davis

2001-01-01

143

Two Electrophoresis Experiments for Freshmen in the Health Professions.  

ERIC Educational Resources Information Center

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)

Brabson, G. Dana; Waugh, David S.

1986-01-01

144

The quantification of oxygen toxicity by the technique of cellulose acetate electrophoresis of rat serum proteins  

E-print Network

Proteins. (December 1979) Marcia Wagner Barker, B. S. , Southwestern at Memphis Chairman of Advisory Committee: Dr. William P. Fife Exposure to hyperbaric oxygen is known to cause pulmonary damage, central nervous system dysfunctions, circulatory.... , Equivalent Pressure, for 24 or 48 Hours. . 71 LIST OF ABBREVIATIONS ata ? atmospheres, absolute C. N. S. ? central nervous system f. s. w. - feet of sea water GABA ? gamma-aminobutyric acid HBO ? hyperbaric oxygen OHP ? oxygen at high pressure psia...

Barker, Marcia Wagner

2012-06-07

145

Electrically generated lead(IV) acetate and manganese(III) acetate as reagents for coulometric redox titrations in acetic acid  

Microsoft Academic Search

Summary The conditions were investigated for electrochemical generation of lead(IV) acetate in acetic acid by oxidation of lead(II) acetate on a lead dioxide electrode and on a platinum electrode. Bivalent manganese ions are quantitatively oxidized on a platinum electrode to the tervalent state in the same solvent. Coulometric titration methods for the determination of small amounts of hydroquinone in acetic

Tibor J. Pastor; Vilim J. Vajgand; Zorica Kicovic

1976-01-01

146

ELECTROPHORESIS OF ANTERIOR PITUITARY PROTEINS.  

PubMed

The moving boundary method of electrophoresis has been applied to a study of pituitary extracts and purified protein fractions derived from these extracts. The technique employed was that developed by Tiselius and involved the optical observation of the protein boundaries by Toepler's schlieren method. The present experiments were designed primarily to determine the number of proteins present, the degree of homogeneity of the various fractions, and the electrophoretic mobility of the individual components under standard conditions. The preparations studied included crude gland extracts obtained with dilute alkali, glycerol, and saline; purified pituitary fractions prepared by isoelectric and precipitation procedures; and freshly prepared and aged solutions of crystalline prolactin. The bulk of the crude gland extracts is composed of physiologically inert proteins, the gradual removal of which in the course of the chemical purification procedures could be controlled by electrophoretic analysis. Freshly prepared solutions of crystalline prolactin exhibit a high degree of electrochemical homogeneity. Upon storage, however, a second component, presumably denatured prolactin, is formed. PMID:19870877

Shipley, R A; Stern, K G; White, A

1939-05-31

147

Nonlinear waves in capillary electrophoresis  

PubMed Central

Electrophoretic separation of a mixture of chemical species is a fundamental technique of great usefulness in biology, health care and forensics. In capillary electrophoresis the sample migrates in a microcapillary in the presence of a background electrolyte. When the ionic concentration of the sample is sufficiently high, the signal is known to exhibit features reminiscent of nonlinear waves including sharp concentration ‘shocks’. In this paper we consider a simplified model consisting of a single sample ion and a background electrolyte consisting of a single co-ion and a counterion in the absence of any processes that might change the ionization states of the constituents. If the ionic diffusivities are assumed to be the same for all constituents the concentration of sample ion is shown to obey a one dimensional advection diffusion equation with a concentration dependent advection velocity. If the analyte concentration is sufficiently low in a suitable non-dimensional sense, Burgers’ equation is recovered, and thus, the time dependent problem is exactly solvable with arbitrary initial conditions. In the case of small diffusivity either a leading edge or trailing edge shock is formed depending on the electrophoretic mobility of the sample ion relative to the background ions. Analytical formulas are presented for the shape, width and migration velocity of the sample peak and it is shown that axial dispersion at long times may be characterized by an effective diffusivity that is exactly calculated. These results are consistent with known observations from physical and numerical simulation experiments. PMID:20238181

Ghosal, Sandip; Chen, Zhen

2011-01-01

148

Succession of bacterial and fungal communities during a traditional pot fermentation of rice vinegar assessed by PCR-mediated denaturing gradient gel electrophoresis  

Microsoft Academic Search

Denaturing gradient gel electrophoresis (DGGE) based on small subunit rRNA gene was applied to a traditional rice vinegar fermentation process in which the conversion of rice starch into acetic acid proceeded in a pot. The fungal DGGE profile indicated that the transition from Aspergillus oryzae to Saccharomyces sp. took place at the initial stage at which alcohol production was observed.

Shin Haruta; Shintaro Ueno; Isao Egawa; Kazunori Hashiguchi; Akira Fujii; Masanobu Nagano; Masaharu Ishii; Yasuo Igarashi

2006-01-01

149

Study of disposable microdevices for DNA electrophoresis  

E-print Network

A study was undertaken to determine if a microfluidic chip, made of economical plastic materials, is feasible. The chip was designed to perform gel electrophoresis, specifically of DNA fragments for either sequencing or ...

Timp, Winston (Winston G.)

2005-01-01

150

Affinity Electrophoresis Using Ligands Attached To Polymers  

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

151

Aptamers in Affinity Separations:Capillary Electrophoresis  

Microsoft Academic Search

Assays employing aptamers in capillary electrophoresis (CE), including competitive and noncompetitive assays, fluorescence polarization (FP) assays, nonequilibrium capillary electrophoresis of equilibrium mixtures, and affinity-polymerase chain reaction-CE assays, are summarized. These assays can be used to estimate dissociation rate and equilibrium binding constants, determine binding stoichiometries, study molecular interactions, and quantitatively determine specific analytes (e.g., proteins) in complex media. They can

Jeffrey W. Guthrie; Yuanhua Shao; X. Chris Le

2009-01-01

152

On-line process monitoring of water-soluble ions in pulp and paper machine waters by capillary electrophoresis  

Microsoft Academic Search

In this study, capillary electrophoresis (CE) was used for separation of inorganic and organic ions from waters of paper and paperboard machines at mills. The instrument was constructed for on-line measurements by building a batch-type sample feeding unit. Chloride, thiosulphate, sulphate, oxalate, sulphite, hydrogen sulphide, formate, carbonate, phosphate and acetate in the process water samples were separated using an ion-specific

Raimo Kokkonen; Heli Sirén; Seppo Kauliomäki; Stella Rovio; Kaija Luomanperä

2004-01-01

153

Dual-cloud point extraction and tertiary amine labeling for selective and sensitive capillary electrophoresis-electrochemiluminescent detection of auxins  

Microsoft Academic Search

The low concentrations of the auxins in samples of plant tissue necessitate the use of selective and sensitive techniques for their quantification. Herein a selective and sensitive method based on dual-cloud point extraction (dCPE) and tertiary amine labeling for the quantification of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) by capillary electrophoresis-electrochemiluminescence (CE-ECL) is proposed. The procedure for dCPE included

Xue-Bo Yin; Jun-Min Guo; Wei Wei

2010-01-01

154

Correlation between acetic acid resistance and characteristics of PQQ-dependent ADH in acetic acid bacteria  

Microsoft Academic Search

In this study, we compared the growth properties and molecular characteristics of pyrroloquinoline quinone (PQQ)-dependent alcohol dehydrogenase (ADH) among highly acetic acid-resistant strains of acetic acid bacteria. Ga. europaeus exhibited the highest resistance to acetic acid (10%), whereas Ga. intermedius and Acetobacter pasteurianus resisted up to 6% of acetic acid. In media with different concentrations of acetic acid, the maximal

Janja Trcek; Hirohide Toyama; Jerzy Czuba; Anna Misiewicz; Kazunobu Matsushita

2006-01-01

155

The fractionation of high-molecular-weight ribonucleic acid by polyacrylamide-gel electrophoresis  

PubMed Central

1. Gels were prepared with recrystallized acrylamide and bisacrylamide. Electrophoresis was in tris–sodium acetate–EDTA buffer for 0·5 to 3hr. Gels were scanned at 280 or 265m?. Techniques are described for slicing and radioactive counting. 2. The mobility of RNA was inversely related to the sedimentation coefficient and varied with gel concentration. Electrophoresis in 2·2–2·6% gels gives a fractionation similar to density-gradient centrifugation. It shows the two ribosomal RNA components, the 45s precursor, transfer RNA and minor components. In 5% and 7·5% gels, 4s and 5s RNA separated and ribosomal RNA was excluded. 3. The resolution is greater and more detailed than by centrifugation, and many samples can be analysed simultaneously and rapidly. PMID:5339944

Loening, U. E.

1967-01-01

156

Three methods of capillary electrophoresis compared with high-resolution agarose gel electrophoresis for serum protein electrophoresis.  

PubMed

We assessed the BioFocus 2000 capillary electrophoresis instrument for use in a routine clinical laboratory. We examined 210 serum samples received for serum protein electrophoresis by four methods: (1) The Bio-Rad HR015EC high-resolution serum protein kit on the BioFocus; (2) the Jenkins-Guerin (JG) method on the Applied Biosystems 270A HT Capillary Electrophoresis System (JG-ABI); (3) the Jenkins-Guerin method using the BioFocus (JG-BF); and (4) the quantitation of monoclonal bands found in 76 of the 210 samples was assayed by Helena Titan Hi-Res agarose gel electrophoresis (HRAGE). The correlation coefficient between the three sets of capillary electrophoresis monoclonal band results and the Helena quantitation was 0.92 or better. Although the quantitative comparison of monoclonal bands by HR015EC was very good, the lack of sharpness of monoclonal bands using the HR015EC kit meant our preference was to use the JG method on either the ABI or on the Biofocus. PMID:9892066

Jenkins, M A

1998-12-11

157

Membrane comparison for wine clarification by microfiltration  

Microsoft Academic Search

In this work ten different polymeric microfiltration membranes of different materials polyethersulfone (PES), cellulose mixed esters (CE), cellulose acetate (CA), polypropylene (PP) and nylon (NY) with different pore diameters and of different commercial companies have been tested for wine clarification. A stirred cell has been used in all the membrane experiments. The objective has been to find the most suitable

Ana Urkiaga; Libe De Las Fuentes; Marta Acilu; Janire Uriarte

2002-01-01

158

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

PubMed

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. PMID:22465769

Pielesz, A

2012-07-01

159

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

PubMed

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. PMID:16378615

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

2006-04-21

160

Isolation and Partial Characterization of the Major Amide-Linked Conjugate of Indole-3-Acetic Acid from Phaseolus vulgaris L. 1  

PubMed Central

A major indole-3-acetic acid conjugate from Phaseolus vulgaris seed has been isolated and partially characterized. It is a 3 kilodalton peptide with apparently 2 indole-3-acetyl moieties in amide linkage per peptide. The indole-3-acetic acid component was identified by gas chromatography-mass spectrometry and the peptide characterized by polyacrylamide gel electrophoresis, by amino acid analysis using dabsyl derivatives and by its Fourier transform-infrared spectrum. This is the first higher molecular weight amide-linked indole-3-acetic acid conjugate to be characterized from higher plants. Images Fig. 4 PMID:16664615

Bialek, Krystyna; Cohen, Jerry D.

1986-01-01

161

Supramolecular gel electrophoresis of acidic native proteins.  

PubMed

Amphiphilic tris-urea molecules self-assemble into a supramolecular hydrogel in tris(hydroxymethyl)aminomethane-glycine buffer. The supramolecular hydrogel is used as a matrix for the electrophoresis of acidic native proteins, in which proteins are separated based on their isoelectric points rather than their molecular weights. The proteins remain in their native forms during migration, and their activities are retained after electrophoresis. Glucoside substituents on the amphiphilic tris-urea molecule allow for the affinity electrophoresis of a carbohydrate-binding protein to be performed. The proteins can be efficiently recovered from the supramolecular hydrogel using a simple procedure. This is a major advantage of using this noncovalent, self-assembled material. PMID:25147927

Munenobu, Kanako; Hase, Takayuki; Oyoshi, Takanori; Yamanaka, Masamichi

2014-10-01

162

21 CFR 184.1721 - Sodium acetate.  

Code of Federal Regulations, 2013 CFR

...anhydrous or trihydrated form. It is produced synthetically by the neutralization of acetic acid with sodium carbonate or by treating calcium acetate with sodium sulfate and sodium bicarbonate. (b) The ingredient meets the...

2013-04-01

163

21 CFR 184.1721 - Sodium acetate.  

...anhydrous or trihydrated form. It is produced synthetically by the neutralization of acetic acid with sodium carbonate or by treating calcium acetate with sodium sulfate and sodium bicarbonate. (b) The ingredient meets the...

2014-04-01

164

21 CFR 184.1721 - Sodium acetate.  

Code of Federal Regulations, 2012 CFR

...anhydrous or trihydrated form. It is produced synthetically by the neutralization of acetic acid with sodium carbonate or by treating calcium acetate with sodium sulfate and sodium bicarbonate. (b) The ingredient meets the...

2012-04-01

165

21 CFR 184.1721 - Sodium acetate.  

Code of Federal Regulations, 2011 CFR

...anhydrous or trihydrated form. It is produced synthetically by the neutralization of acetic acid with sodium carbonate or by treating calcium acetate with sodium sulfate and sodium bicarbonate. (b) The ingredient meets the...

2011-04-01

166

21 CFR 184.1721 - Sodium acetate.  

Code of Federal Regulations, 2010 CFR

...anhydrous or trihydrated form. It is produced synthetically by the neutralization of acetic acid with sodium carbonate or by treating calcium acetate with sodium sulfate and sodium bicarbonate. (b) The ingredient meets the...

2010-04-01

167

Concentrating aqueous acetate solutions with tertiary amines  

E-print Network

Water may be extracted from aqueous calcium acetate or sodium acetate solutions using low miscibility, low molecular weight tertiary amines, e.g. triethylamine (TEA) and N,N- dietliylmethylaniine (DEMA). This novel extraction technology...

Lee, Champion

2012-06-07

168

Application of Microchip Electrophoresis for Clinical Tests  

NASA Astrophysics Data System (ADS)

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 ?-amylase activity in human plasma using microchip electrophoresis.

Yatsushiro, Shouki; Kataoka, Masatoshi

169

Aptamers in Affinity Separations:Capillary Electrophoresis  

Microsoft Academic Search

\\u000a Assays employing aptamers in capillary electrophoresis (CE), including competitive and noncompetitive assays, fluorescence\\u000a polarization (FP) assays, nonequilibrium capillary electrophoresis of equilibrium mixtures, and affinity-polymerase chain\\u000a reaction-CE assays, are summarized. These assays can be used to estimate dissociation rate and equilibrium binding constants,\\u000a determine binding stoichiometries, study molecular interactions, and quantitatively determine specific analytes (e.g., proteins)\\u000a in complex media. They can

Jeffrey W. Guthrie; Yuanhua Shao; X. Chris Le

170

Degradation of skeletal muscle plasma membrane proteins by calpain  

Microsoft Academic Search

Summary Observations described here provide the first demonstration that calpain (Ca2+-dependent cysteine protease) can degrade proteins of skeletal muscle plasma membranes. Frog muscle plasma membrane vesicles were incubated with calpain preparations and alterations of protein composition were revealed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Calpain II (activated by millimolar concentrations of Ca2+) was isolated from frog skeletal muscle, but

S. I. M. Zaidi; H. T. Narahara

1989-01-01

171

Respiratory chain supercomplexes in the plant mitochondrial membrane  

Microsoft Academic Search

The intricate, heavily folded inner membrane of mito- chondria houses the respiratory chain complexes. These complexes, together with the ATP synthase complex, are responsible for energy production, which is stored as ATP. The structure of the individual membrane-bound protein components has been well characterized. In particular, the use of Blue-native polyacrylamide gel electrophoresis has been instrumental in recent years in

Natalya V. Dudkina; Jesco Heinemeyer; Stephanie Sunderhaus; Egbert J. Boekema; Hans-Peter Braun

2006-01-01

172

Role of gravity in preparative electrophoresis  

NASA Technical Reports Server (NTRS)

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.

Bier, M.

1975-01-01

173

Ratcheted electrophoresis for rapid particle transport.  

PubMed

Ratcheted electrophoresis of contact-charged particles allows for high speed transport through microfluidic channels over large distances and even against fluid flows. Using a set of predictive design heuristics, we demonstrate an extension of this microfluidic ratchet to separate conductive particles from a particle suspension. PMID:24064932

Drews, Aaron M; Lee, Hee-Young; Bishop, Kyle J M

2013-11-21

174

Enantiomeric resolution study by capillary electrophoresis  

Microsoft Academic Search

The enantiomeric separation of several arylpropionic acids, namely carprofen, cicloprofen, flurbiprofen, ibuprofen, indoprofen, ketoprofen, naproxen and suprofen has been studied by capillary zone electrophoresis using different chiral selectors added to the background electrolyte with the aim to find the optimum experimental conditions for both qualitative and quantitative purposes. The chiral selectors used included two ?-cyclodextrin derivatives and a glycosidic antibiotic,

Salvatore Fanali; Claudia Desiderio; Zeineb Aturki

1997-01-01

175

DNA DAMAGE QUANTITATION BY ALKALINE GEL ELECTROPHORESIS.  

SciTech Connect

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.

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

2004-03-24

176

The Genetic Science Learning Center: Gel Electrophoresis  

NSDL National Science Digital Library

Gel Electrophoresis, designed and run by the University of Utah, is an interactive program that allows the student to learn and practice basic techniques that molecular biologists use every day. This program is an interactive animated procedure that allows the user to "see" DNA strands and instructs the student or user on the basics of DNA.

2007-04-05

177

Gel electrophoresis of intact subcellular particles.  

PubMed

The review describes the application of gel electrophoresis to the characterization and separation of viruses, ribosomes, vesicles and other subcellular particles. The preparation of the sample, the choice of the buffer, the gel medium, the apparatus and the detection of the particle (staining and scanning) as well as the necessary theory are discussed. This includes the mathematical evaluation of experimental data on the basis of Ferguson plots using the extended Ogston theory. Simple methods and sophisticated computer simulation techniques are described and exemplified in application to the determination of particle size and charge, the pore size of the gel (unpublished data) and the two-dimensional agarose electrophoresis (unpublished). It is shown that the nature of the particle (e.g. spherical or rod-shaped, pliable or rigid texture) determines the shape of the non-linear Ferguson plot. In addition, the review gives a number of practical applications of gel electrophoresis, isoelectric focusing, titration curves and immuno-electrophoresis to subcellular particles. Pros and cons are evaluated. A comparison with other analytical procedures is made. The review is concluded by a futuristic outlook. PMID:3305546

Tietz, D

1987-07-17

178

Dynamical characterization of a cellulose acetate polysaccharide.  

PubMed

This work brings together dynamical and structural information at a molecular level for cellulose acetate being an original contribution to the general description of polysaccharide properties. In particular, it allowed reinterpreting the secondary relaxation mechanisms that are still controversial in the literature; a compilation of data provided by different authors is provided. Detailed dynamical information is provided by dielectric relaxation spectroscopy (DRS) (10(-1)-10(6) Hz) for cellulose acetate (CA) in the sub-T(g) region below ambient temperature; results were compared with cellulose acetate structured as an asymmetric membrane (CAmb). In samples with low water content, two secondary relaxation processes between 173 and 298 K were identified by DRS, associated with localized mobility. The process located at the lowest temperatures (process I) has a different mobility in CA relative to CAmb. The identical crystalline/amorphous state of both materials allowed rationalizing the distinct behavior in terms of polymeric arrangement and ability for water uptake. The looser structure of the CA relative to CAmb as confirmed by FTIR, TGA, and DSC analysis makes more sites accessible to water molecules, resulting in a higher water retention in CA (2.73% w/w) relative to CAmb (1.60% w/w) and an increased molecular mobility in the former due to a plasticizing effect. In both materials, process I is significantly influenced by hydration, shifting to higher frequencies and lower temperatures upon water uptake. This process seems to be associated with mobility occurring within the monomeric unit, which embraces the two anhydroglucose rings connected by the glycosidic linkage and the polar groups directly attached to it. It should involve a very limited length scale, as suggested by its location, far below the glass transition, and the tau(infinity) value with a low entropic effect. The relaxation process that emerges later, process II, is similar for both samples being much less influenced by water but experiencing a slight antiplasticizing effect shifting to lower frequencies and higher temperatures upon hydration. It should involve side group motions, strongly coupled to the mobility of the anhydroglucose rings, which become hindered probably due to establishment of H-bonds with water molecules. The plasticizing/antiplasticizing effect is being discussed only on the basis of the frequency position of the relaxation peak. Processes I and II merge into a broad relaxation (gamma(dry)) upon water removal in both CA and CAmb, however evolving slower in the former with drying, due to a more disordered structure of CA that allows water to interact with more internal sites in the polymer. At higher temperatures (T > or = 353 K), a process emerges in the high frequency side of the dynamic alpha-relaxation which is compatible with a beta(JG)-relaxation. The structured specimen CAmb provided an additional way to probe the morphological changes undergone by the material when annealed to temperatures higher than 353 K, originating an increase in the dielectric response. This effect can be associated with a skin densification and partial collapse of the membrane porous network, as observed by SEM. PMID:20690651

Sousa, Miriam; Brás, Ana Rita; Veiga, Helena Isabel M; Ferreira, Frederico Castelo; de Pinho, Maria Norberta; Correia, Natália T; Dionísio, Madalena

2010-09-01

179

Study on dicarboxylic acids in aerosol samples with capillary electrophoresis.  

PubMed

The research was performed to study the simultaneous detection of a homologous series of ? , ? -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? ? 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). PMID:24729915

Adler, Heidi; Sirén, Heli

2014-01-01

180

Anodically generated cobalt(III) acetate as reagent for coulometric titrations in acetic acid  

Microsoft Academic Search

Summary Conditions for the anodic generation of cobalt(III) acetate with high current efficiency in non-aqueous solutions of potassium acetate in acetic acid have been investigated. The presence of water or acetic anhydride in the anolyte diminishes the amount of the generated oxidant. The stability of the generated cobalt(III) acetate solution is decreased in the presence of water and at elevated

T. J. Pastor; I. ?iri?

1985-01-01

181

ANALYSIS OF THE PROTEINS OF RAT SERUM BY STARCH ELECTROPHORESIS AND BY CATIONIC DETERGENT ANALYSIS  

PubMed Central

A protein of unusual characteristics has been identified in normal rat sera by electrophoretic separation at pH 8.6, followed by precipitation of each fraction with a cationic detergent. This protein, which is closely identified with albumin after electrophoresis at pH 8.6, precipitates with cationic detergent at a low pH in contrast to albumin which precipitates with detergent only at a high pH. This protein has characteristics of a globulin and is designated as a "fast alpha fraction." This fraction and albumin are present in about equal amounts in sera of normal rats. A separation of the fast alpha fraction can be made by electrophoresis in an acetate buffer of pH 4.25 and by precipitation according to a modified Cohn, cold-alcohol technique. A protein of similar characteristics has not been found in either human or rabbit sera studied by the same method of electrophoresis and subsequent sub-fractionation with cationic detergent. PMID:14406458

Jacox, Ralph F.

1959-01-01

182

Validation of capillary electrophoresis method for determination of N-methylpyrrolidine in cefepime for injection.  

PubMed

The present study relates to a new capillary electrophoresis method for the determination of N-methylpyrrolidine, an impurity considered to be toxic and also potential degradation impurity in cefepime hydrochloride drug substance. The newly developed capillary electrophoresis method for determining the content of N-methylpyrrolidine in cefepime for injection has been validated as per International Conference on Harmonization (ICH) guidelines to prove the selectivity, sensitivity, suitability, robustness, and ruggedness of the method. This simple, efficient, and rapid methodology may be used by pharmaceutical industry for routine analysis as well as during stability studies. The newly developed capillary electrophoresis method to determine the content of N-methylpyrrolidine in cefepime for injection requires 10 min for data acquisition, and uses an indirect UV photometry method to detect the analyte signal at 240 nm against the reference signal at 210 nm. The electrophoretic system is optimized to get stable base line, higher signal to noise ratio and peaks with narrow peak width. The method employs bare fused silica capillary with extended light path, effective length of capillary is 56 cm and inner diameter of capillary is 50 ?m, 5 mmole of imidazole buffer adjusted to pH 5.1 with 3 molar acetic acid solution is used as background electrolyte. The sample is introduced in hydrodynamic mode employing pressure of 50 mbar for 5 s, and the desired separation is achieved with constant applied voltage of 25 kV at ambient temperature (~25°C). PMID:21044414

Prasanna, S John; Sharma, Hemant Kr; Mukkanti, K; Kumar, V Jagadeesh; Raja, G; Sivakumaran, M

2010-11-01

183

Molecular Structure of Ethyl acetate  

NSDL National Science Digital Library

Ethyl acetate is a colorless, volatile liquid with a mild and fragrant odor. It is used as solvent in chemistry laboratories but can also be found in many household products such as paints, coatings, and adhesives. The compound is also used in some extraction processes such as decaffeination or purification of antibiotics. It is present in both nail polish and removers. Some synthetic fruit essences may contain this and other esters. Etymologists like to use this solvent for insect collecting as the vapor kill the insect quickly and keep it soft for mounting.

2006-03-08

184

Hydrogen peroxide resistance of Acetobacter pasteurianus NBRC3283 and its relationship to acetic acid fermentation.  

PubMed

The bacterium Acetobacter pasteurianus can ferment acetic acid, a process that proceeds at the risk of oxidative stress. To understand the stress response, we investigated catalase and OxyR in A. pasteurianus NBRC3283. This strain expresses only a KatE homolog as catalase, which is monofunctional and growth dependent. Disruption of the oxyR gene increased KatE activity, but both the katE and oxyR mutant strains showed greater sensitivity to hydrogen peroxide as compared to the parental strain. These mutant strains showed growth similar to the parental strain in the ethanol oxidizing phase, but their growth was delayed when cultured in the presence of acetic acid and of glycerol and during the acetic acid peroxidation phase. The results suggest that A. pasteurianus cells show different oxidative stress responses between the metabolism via the membrane oxidizing pathway and that via the general aerobic pathway during acetic acid fermentation. PMID:18838821

Okamoto-Kainuma, Akiko; Ehata, Yasunori; Ikeda, Manami; Osono, Takemasa; Ishikawa, Morio; Kaga, Takayuki; Koizumi, Yukimichi

2008-10-01

185

Contour-clamped homogeneous electric field electrophoresis of Staphylococcus aureus  

Microsoft Academic Search

Contour-clamped homogeneous electric field (CHEF) electrophoresis is a technique of pulsed-field gel electrophoresis that enables the resolution of large fragments of DNA that cannot be resolved by conventional gel electrophoresis. The procedure involves the application of controlled electric fields that change direction at a predetermined angle to samples of DNA that have been embedded in an agarose gel matrix and

Warren B Grubb; Frances G O'Brien; Edet E Udo

2007-01-01

186

Continuous Sample Preparation Using Freeflow electrophoresis On A Silicon Microstructure  

Microsoft Academic Search

SUMMARY pretreatment using free-flow electrophoresis 151, HPLC [61, rapid capillary electrophoresis 17, 81 and A miniaturized version of a continuous-flow synchronized cyclic capillary electrophoresis [9], have electrophoretic device is presented. The small internal demonstrated the advantages and problems of pTAS. volumes make this technique attractive for biochemists. Separations of small ions, peptides and whole cells are given.

Daniel E. Raymond; Andreas Manz; H. Michael Widmer

1995-01-01

187

Tonoplast vesicles of opposite sidedness from soybean hypocotyls by preparative free-flow electrophoresis.  

PubMed

Tonoplast vesicles were purified from a microsomal fraction isolated from etiolated soybean hypocotyls (Glycine max L.) by preparative free-flow electrophoresis. Marker enzyme determinations and immunoblot analysis against the vacuolar-ATPase confirmed the nature and the purity of the isolated membranes. A purified tonoplast fraction also was obtained by consecutive sucrose and glycerol centrifugation which was further resolved into two different populations of vesicles (T(A) and T(B)) by free-flow electrophoresis. The determination of the sidedness of these different vesicles included concanavalin A binding as an imposed label, NADH-ferricyanide oxidoreductase cytochemistry, and ATPase latency. The tonoplast fractions, obtained by consecutive sucrose and glycerol gradient centrifugations, were found to consist of a mixture of two populations of vesicles of opposite sidedness. The least electronegative fraction obtained by free-flow electrophoresis (T(B)) consisted predominantly of cytoplasmic side out tonoplast vesicles while a fraction of greater electronegativity (T(A)) contained the cytoplasmic side in tonoplast vesicles. The relative amounts of each type of vesicle varied with the method of homogenization. Razor blade chopping, Polytron, and Waring Blendor homogenization gave predominantly cytoplasmic side out vesicles, whereas mashing with a mortar and pestle gave nearly equal amounts of the two populations of membrane vesicles of different orientation. PMID:16667810

Canut, H; Brightman, A; Boudet, A M; Morré, D J

1990-11-01

188

Tonoplast Vesicles of Opposite Sidedness from Soybean Hypocotyls by Preparative Free-Flow Electrophoresis 1  

PubMed Central

Tonoplast vesicles were purified from a microsomal fraction isolated from etiolated soybean hypocotyls (Glycine max L.) by preparative free-flow electrophoresis. Marker enzyme determinations and immunoblot analysis against the vacuolar-ATPase confirmed the nature and the purity of the isolated membranes. A purified tonoplast fraction also was obtained by consecutive sucrose and glycerol centrifugation which was further resolved into two different populations of vesicles (TA and TB) by free-flow electrophoresis. The determination of the sidedness of these different vesicles included concanavalin A binding as an imposed label, NADH-ferricyanide oxidoreductase cytochemistry, and ATPase latency. The tonoplast fractions, obtained by consecutive sucrose and glycerol gradient centrifugations, were found to consist of a mixture of two populations of vesicles of opposite sidedness. The least electronegative fraction obtained by free-flow electrophoresis (TB) consisted predominantly of cytoplasmic side out tonoplast vesicles while a fraction of greater electronegativity (TA) contained the cytoplasmic side in tonoplast vesicles. The relative amounts of each type of vesicle varied with the method of homogenization. Razor blade chopping, Polytron, and Waring Blendor homogenization gave predominantly cytoplasmic side out vesicles, whereas mashing with a mortar and pestle gave nearly equal amounts of the two populations of membrane vesicles of different orientation. Images Figure 3 Figure 6 Figure 7 PMID:16667810

Canut, Hervé; Brightman, Andrew; Boudet, Alain M.; Morré, D. James

1990-01-01

189

Electron transport in acetate-grown Methanosarcina acetivorans  

PubMed Central

Background Acetate is the major source of methane in nature. The majority of investigations have focused on acetotrophic methanogens for which energy-conserving electron transport is dependent on the production and consumption of H2 as an intermediate, although the great majority of acetotrophs are unable to metabolize H2. The presence of cytochrome c and a complex (Ma-Rnf) homologous to the Rnf (Rhodobacter nitrogen fixation) complexes distributed in the domain Bacteria distinguishes non-H2-utilizing Methanosarcina acetivorans from H2-utilizing species suggesting fundamentally different electron transport pathways. Thus, the membrane-bound electron transport chain of acetate-grown M. acetivorans was investigated to advance a more complete understanding of acetotrophic methanogens. Results A component of the CO dehydrogenase/acetyl-CoA synthase (CdhAE) was partially purified and shown to reduce a ferredoxin purified using an assay coupling reduction of the ferredoxin to oxidation of CdhAE. Mass spectrometry analysis of the ferredoxin identified the encoding gene among annotations for nine ferredoxins encoded in the genome. Reduction of purified membranes from acetate-grown cells with ferredoxin lead to reduction of membrane-associated multi-heme cytochrome c that was re-oxidized by the addition of either the heterodisulfide of coenzyme M and coenzyme B (CoM-S-S-CoB) or 2-hydoxyphenazine, the soluble analog of methanophenazine (MP). Reduced 2-hydoxyphenazine was re-oxidized by membranes that was dependent on addition of CoM-S-S-CoB. A genomic analysis of Methanosarcina thermophila, a non-H2-utilizing acetotrophic methanogen, identified genes homologous to cytochrome c and the Ma-Rnf complex of M. acetivorans. Conclusions The results support roles for ferredoxin, cytochrome c and MP in the energy-conserving electron transport pathway of non-H2-utilizing acetotrophic methanogens. This is the first report of involvement of a cytochrome c in acetotrophic methanogenesis. The results suggest that diverse acetotrophic Methanosarcina species have evolved diverse membrane-bound electron transport pathways leading from ferredoxin and culminating with MP donating electrons to the heterodisulfide reductase (HdrDE) for reduction of CoM-S-S-CoB. PMID:21781343

2011-01-01

190

Chitosan hollow fiber membranes.  

PubMed

Chitosan hollow fibers were produced by wet spinning, taking advantage of the unique rheological properties of highly viscous chitosan solutions in acetic acid. The mechanical and separation properties of hollow fibers were tested. The mechanical properties were determined by measuring tensile force, tensile stress, elongation, and initial elasticity module. The separation properties were specified by determining retention coefficients of particular blood components and determining cut-off of the membrane by the analysis of dextran molecular weight distribution in the feed and permeate using a technique of gel chromatography (GPC)-Shimadzu gel chromatograph. PMID:14691939

Modrzejewska, Zofia; Eckstein, Wojciech

2004-01-01

191

A new approach to electrophoresis in space  

NASA Technical Reports Server (NTRS)

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.

Snyder, Robert S.; Rhodes, Percy H.

1990-01-01

192

DNA electrophoresis in a nanofence array†  

PubMed Central

We present the design and implementation of an oxidized silicon “nanofence array” for long DNA electrophoresis. The device consists of a periodic array of post-filled regions (the nanofences) alternating with empty channel regions. Even in this prototype version, the nanofence array provides the resolving power of a hexagonal nanopost array without requiring any direct-write nanopatterning steps such as electron-beam lithography. Through detailed single molecule investigations, we demonstrate that the origin of the resolving power of the nanofence array is not a reduction in band broadening, which might be expected from the theories for DNA electrophoresis in post arrays. Rather, the enhanced stretching of the hooked DNA by the uniform electric field between nanofences increases the efficiency of the collisions. PMID:22388662

Park, Sung-Gyu; Olson, Daniel W.

2012-01-01

193

Capillary Electrophoresis Applied to Proteomic Analysis  

PubMed Central

In the postgenomic era, proteomics has become a dominant field for identifying and quantifying the complex protein machinery of the cell. The expression levels, post-translational modifications, and specific interactions of proteins control the biology of such processes as development, differentiation, and signal transduction. Studies of the proteins involved in these processes often leads to a better understanding of biology and of human disease. Powerful separation techniques and sensitive detection methods enable researchers to untangle these complicated networks of processes. Capillary electrophoresis coupled with either mass spectrometry or laser-induced fluorescence are two of the techniques that make this possible. This review will cover proven capillary electrophoresis-based methods for proteomics on the cell and tissue level and their application in biological and clinical studies, relevant new developments in enabling technology such as microfluidic CE-MS demonstrated on model systems, and comment on the future of CE in proteomics. PMID:19360788

Fonslow, Bryan R.; Yates, John R.

2012-01-01

194

Sampling techniques for single-cell electrophoresis  

PubMed Central

Cells are extraordinarily complex, containing thousands of different analytes with concentrations spanning at least nine orders of magnitude. Analyzing single cells instead of tissue homogenates provides unique insights into cell-to-cell heterogeneity and aids in distinguishing normal cells from pathological ones. The high sensitivity and low sample consumption of capillary and on-chip electrophoresis, when integrated with fluorescence, electrochemical, and mass spectrometric detection methods, offer an ideal toolset for examining single cells and even subcellular organelles; however, the isolation and loading of such small samples into these devices is challenging. Recent advances have addressed this issue by interfacing a variety of enhanced mechanical, microfluidic, and optical sampling techniques to capillary and on-chip electrophoresis instruments for single-cell analyses. PMID:22288071

Cecala, Christine; Sweedler, Jonathan V.

2013-01-01

195

Portable electrophoresis apparatus using minimum electrolyte  

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

196

Capillary Electrophoresis with Indirect Electrochemiluminescence Detection  

Microsoft Academic Search

An indirect electrochemiluminescence (IECL) detection for capillary electrophoresis (CE) is presented in this article. IECL is based on the inhibition of Ru(bpy)3 \\/TPA system. The developed technique is successfully applied to the analysis of phenolic compounds: phenol, o?chlorophenol, p?nitrophenol, and 2,4,6?trinitrophenol. The factors that influenced the separation and detection were investigated in detail. On the optimized condition, the tested phenols

Jianzhen Kang; Jifeng Liu; Haibo Qiu; Jilin Yan; Xiurong Yang; Erkang Wang

2005-01-01

197

Method and apparatus for continuous electrophoresis  

DOEpatents

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.

Watson, Jack S. (Knoxville, TN)

1992-01-01

198

Extensions of Gel Electrophoresis with Proteins  

NSDL National Science Digital Library

This inquiry activity is intended to help familiarize students with the procedure of agarose electrophoresis and to make them aware of the types of proteins within tissue samples. This inquiry activity was developed by a K-12 science teacher in the American Physiological SocietyÃÂs 2006 Frontiers in Physiology Program. The NSES Standards addressed by this activity are current as of the year of development. For more information on the Frontiers in Physiology Program, please visit www.frontiersinphys.org.

Mr. Brian McClain (Amos P. Godby High School)

2006-04-01

199

Capillary electrophoresis: new technology for DNA diagnostics.  

PubMed

New innovations in the diagnostic laboratory achieve their full potential when they can be automated. Increasingly molecular biology (DNA) techniques are being utilised in traditional pathology disciplines, as well as the more recent ones of cytogenetics and molecular genetics. Molecular biology was first exploited for diagnostic purposes when Southern blotting became established. However the time-consuming nature of the methodology, as well as the skills required, made it difficult for Southern blotting to be used routinely in the service laboratory. Subsequently the invention of PCR facilitated the approach to DNA diagnostics. Today PCR in commercial or home-made kits is used for a range of procedures. The steps required to amplify DNA with PCR can also be fully automated. However the analysis of PCR products, which frequently requires slab gel electrophoresis and toxic chemicals or radioisotopes for visualisation, remains difficult to automate. An alternative way for analysing PCR products is now available through capillary electrophoresis. With this technique, automation can be extended to sample loading, electrophoresis and data analysis. The use of toxic chemicals or radioisotopes can be avoided. PMID:9770198

Le, H; Fung, D C; Yu, B; Trent, R J

1998-08-01

200

Electrophoresis in lyotropic polymer liquid crystals  

PubMed Central

Excellent electrophoretic separations of a variety of biological molecules can be accomplished by using uncharged, triblock copolymers as the “gel” media. These copolymers form uncrosslinked, lyotropic liquid crystalline phases of large micelles between which molecules must travel. Unlike crosslinked hydrogels in common use, these alternative media have highly ordered internal structures. Pluronic F127, representative of the copolymer class, contains poly(ethylene oxide) (EO) and poly(propylene oxide) (PO) units with an approximate molecular formula (EO)106(PO)70(EO)106. Concentrated (18–30%) solutions of Pluronic F127 are freely flowing liquids at low temperature (0–5°C) but form gel-like, cubic liquid crystals of large, spherical micelles when warmed. The utility of these media is illustrated by separations of linear, double-stranded DNA up to 3,000 bp long by conventional electrophoresis, and of single-stranded DNAs from 4 to 60 nt long by capillary electrophoresis. Extraordinary separations of supercoiled DNAs were also obtained by capillary electrophoresis. The versatility, availability, and ease of use of Pluronic polymers offer major advantages over conventional media for preparative and high performance analytical separations of nucleic acids and other biomolecules. Mechanisms of molecular transport and separation operating in polymer liquid crystals must differ in fundamental ways from those in crosslinked gels. Lyotropic polymer liquid crystals are unique systems for elucidating mechanisms of macromolecule migration in ordered, dense media, and provide opportunities in separations science. PMID:9465050

Rill, Randolph L.; Locke, Bruce R.; Liu, Yingjie; Van Winkle, David H.

1998-01-01

201

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

PubMed

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. PMID:12627448

Kvasnicka, Frantisek

2003-03-01

202

Metabolism of steroid acetates by Streptomyces albus.  

PubMed

Fermentation of 16-dehydropregnenolone acetate (1a) with Streptomyces albus yielded 16-dehydropregnenolone (1b) and 16-dehydroprogesterone (IIa). Similar incubation of pregnenolone acetate (Ic) with the strain afforded pregnenolone (Id), progesterone (IIb) and 20 alpha-hydroxy progesterone (IIc) while dehydroepiandrosterone acetate (IIIa) under the conditions was converted to dehydroepiandrosterone (IIIb), androstenedione (IVa) and testosterone (IVc). The strain was also capable of converting testosterone acetate (IVb) having the 17-acetoxy function in the 5-membered D-ring to testosterone (IVc) and androstenedione (IVa). All the products were identified by the application of various chemical and spectrometric techniques. PMID:6708550

Mukherjee, A; Mahato, S B

1984-03-01

203

Capillary electrophoresis-based assessment of nanobody affinity and purity.  

PubMed

Drug purity and affinity are essential attributes during development and production of therapeutic proteins. In this work, capillary electrophoresis (CE) was used to determine both the affinity and composition of the biotechnologically produced "nanobody" EGa1, the binding fragment of a heavy-chain-only antibody. EGa1 is an antagonist of the epidermal growth factor receptor (EGFR), which is overexpressed on the surface of tumor cells. Using a background electrolyte (BGE) of 50mM sodium phosphate (pH 8.0) in combination with a polybrene-poly(vinylsulfonic acid) capillary coating, CE analysis of EGa1 showed the presence of at least three components. Affinity of the EGa1 components towards the extracellular domain of EGFR was assessed by adding different concentrations (0-12 nM) of the receptor to the BGE while measuring the effective electrophoretic mobility of the respective EGa1 components. Binding curves obtained by plotting electrophoretic mobility shifts as a function of receptor concentration, yielded dissociation constants (Kd) of 1.65, 1.67, and 1.75 nM for the three components, respectively; these values were comparable to the Kd of 2.1 nM obtained for the bulk EGa1 product using a cellular assay. CE with mass spectrometry (MS) detection using a BGE of 25 mM ammonium acetate (pH 8.0) revealed that the EGa1 sample comprised of significant amounts of deamidated, bisdeamidated and N-terminal pyroglutamic acid products. CE-MS using a BGE of 100mM acetic acid (pH 2.8) in combination with a polybrene-dextran sulfate-polybrene capillary coating demonstrated the additional presence of minor products related to incomplete removal of the signal peptide from the produced nanobody. Combining the results obtained from affinity CE and CE-MS, it is concluded that the EGa1 nanobody product is heterogeneous, comprising highly-related proteins that exhibit very similar affinity towards EGFR. PMID:24626396

Haselberg, Rob; Oliveira, Sabrina; van der Meel, Roy; Somsen, Govert W; de Jong, Gerhardus J

2014-03-25

204

Positron scattering from vinyl acetate  

NASA Astrophysics Data System (ADS)

Using a Beer-Lambert attenuation approach, we report measured total cross sections (TCSs) for positron scattering from vinyl acetate (C4H6O2) in the incident positron energy range 0.15-50 eV. In addition, we also report an independent atom model with screening corrected additivity rule computation results for the TCSs, differential and integral elastic cross sections, the positronium formation cross section and inelastic integral cross sections. The energy range of these calculations is 1-1000 eV. While there is a reasonable qualitative correspondence between measurement and calculation for the TCSs, in terms of the energy dependence of those cross sections, the theory was found to be a factor of ˜2 larger in magnitude at the lower energies, even after the measured data were corrected for the forward angle scattering effect.

Chiari, L.; Zecca, A.; Blanco, F.; García, G.; Brunger, M. J.

2014-09-01

205

Putative ABC Transporter Responsible for Acetic Acid Resistance in Acetobacter aceti  

PubMed Central

Two-dimensional gel electrophoretic analysis of the membrane fraction of Acetobacter aceti revealed the presence of several proteins that were produced in response to acetic acid. A 60-kDa protein, named AatA, which was mostly induced by acetic acid, was prepared; aatA was cloned on the basis of its NH2-terminal amino acid sequence. AatA, consisting of 591 amino acids and containing ATP-binding cassette (ABC) sequences and ABC signature sequences, belonged to the ABC transporter superfamily. The aatA mutation with an insertion of the neomycin resistance gene within the aatA coding region showed reduced resistance to acetic acid, formic acid, propionic acid, and lactic acid, whereas the aatA mutation exerted no effects on resistance to various drugs, growth at low pH (adjusted with HCl), assimilation of acetic acid, or resistance to citric acid. Introduction of plasmid pABC101 containing aatA under the control of the Escherichia coli lac promoter into the aatA mutant restored the defect in acetic acid resistance. In addition, pABC101 conferred acetic acid resistance on E. coli. These findings showed that AatA was a putative ABC transporter conferring acetic acid resistance on the host cell. Southern blot analysis and subsequent nucleotide sequencing predicted the presence of aatA orthologues in a variety of acetic acid bacteria belonging to the genera Acetobacter and Gluconacetobacter. The fermentation with A. aceti containing aatA on a multicopy plasmid resulted in an increase in the final yield of acetic acid. PMID:16391084

Nakano, Shigeru; Fukaya, Masahiro; Horinouchi, Sueharu

2006-01-01

206

Highly selective and efficient determination of US Environmental Protection Agency priority phenols employing solid-phase extraction and non-aqueous capillary electrophoresis  

Microsoft Academic Search

Non-aqueous capillary electrophoresis has been used in the separation of a complete list of 26 priority phenols included in the 8041 US Environmental Protection Agency method and the 76\\/464\\/EEC European Union directive. A highly selective and efficient separation was obtained when the background electrolyte used was 150 mM ammonium acetate dissolved in N-methylformamide–acetonitrile (75:25). Solid-phase extraction was successfully assayed as

S Morales; R Cela

2000-01-01

207

Nonaqueous capillary zone electrophoresis of synthetic organic polypeptides.  

PubMed

Poly(Nepsilon-trifluoroacetyl-L-lysine) was used as a model solute to investigate the potential of nonaqueous capillary electrophoresis (NACE) for the characterization of synthetic organic polymers. The information obtained by NACE was compared to that derived from size exclusion chromatography (SEC) experiments, and the two techniques were found to be complimentary for polymer characterization. On one hand, NACE permitted (i) the separation of oligomers according to their molar mass and (ii) the separation of the polymers according to the nature of the end groups. On the other hand, SEC experiments were used for the characterization of the molar mass distribution for higher molar masses. Due to the tendency of the solutes (polypeptides) to adsorb onto the fused-silica capillary wall, careful attention was paid to the rinsing procedure of the capillary between runs in order to keep the capillary surface clean. For that purpose, the use of electrophoretic desorption under denaturating conditions was very effective. Optimization of the separation was performed by studying (i) the influence of the proportion of methanol in a methanoVacetonitrile mixture and (ii) the influence of acetic acid concentration in the background electrolyte. Highly resolved separation of the oligomers (up to a degree of polymerization n of approximately 50) was obtained by adding trifluoroacetic acid to the electrolyte. Important information concerning the polymer conformations could be obtained from the mobility data. Two different plots relating the effective mobility data to the degree of polymerization were proposed for monitoring the changes in polymer conformations as a function of the number of monomers. PMID:14710838

Cottet, Hervé; Vayaboury, Willy; Kirby, Daniel; Giani, Olivia; Taillades, Jacques; Schué, François

2003-10-15

208

Oxygen17 and proton nuclear magnetic resonance studies on acetic acid exchange processes of the chloride, nitrate, and acetate of nickel(II) in acetic acid  

Microsoft Academic Search

The exchange rates of acetic acid coordinating to nickel(II) chloride, nickel(II) nitrate, and nickel(II) acetate in neat acetic acid and acetic acid\\/dichloromethane-d2 mixtures were measured by the oxygen-17 and proton NMR line-broadening methods. The activation parameters for the acetic acid exchange on these nickel(II) salts were independent of the concentration of acetic acid (HOAc) in the mixed solvents. The first-order

A. Hioki; S. Funahashi; M. Tanaka

1985-01-01

209

Zone electrophoresis in an inner-cooling wide-bore electrophoresis system with UV detection.  

PubMed

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. PMID:18689944

Guo, Yugao; Liu, Danning; Wang, Huaifeng; Yuan, Ruijuan; Bao, James Jianmin

2008-08-01

210

[Applications of microchip electrophoresis and capillary electrophoresis for screening FLT3-ITD gene mutation in acute myeloid leukemia].  

PubMed

The purpose of the present study was to compare the reliability of microchip electrophoresis and capillary electrophoresis for screening FLT3-ITD gene mutation in acute myeloid leukemia. The FLT3-ITD mutation in the genomic DNA samples from 214 untreated AML patients were separately detected by PCR-microchip electrophoresis and PCR-capillary electrophoresis, then the DNA direct sequencing analysis was carried out. The results from PCR-microchip electrophoresis showed that there were 151 FLT3-ITD mutation negative, 58 FLT3-ITD mutation positive (58/214, 27.1%) and 5 FLT3-ITD mutation doubtful positive (5/214, 2.3%), while the outcomes from PCR-capillary electrophoresis displayed that there were 147 FLT3-ITD mutation negative and 67 FLT3-ITD mutation positive (67/214, 31.3%) without doubtful positive. In the 67 FLT3-ITD mutation positive samples detected by using PCR-capillary electrophoresis, 4 samples were detected as the negative while 5 samples were measured as the doubtful positive by using PCR-microchip electrophoresis. The followed sequencing analysis demonstrated that the above 9 samples were all FLT3-ITD mutation positive, indicating that PCR-capillary electrophoresis was more accurate and sensitive in screening the FLT3-ITD mutation, although statistic analysis showed that there were no significant differences in the detected results between PCR-microchip electrophoresis and PCR-capillary electrophoresis groups (Pearson Chi-squared Test, P > 0.05). It is concluded that both PCR-microchip electrophoresis and PCR-capillary electrophoresis were convenient and fast for screening FLT3-ITD mutation, but the accuracy of PCR-microchip electrophoresis awaits further improvement. PMID:24598649

Leng, Xin; Li, Ling-Di; Li, Jin-Lan; Huang, Xiao-Jun; Ruan, Guo-Rui

2014-02-01

211

Biodegradable Plastics Based on Cellulose Acetate  

Microsoft Academic Search

It is generally known that secondary cellulose acetate (with 53 to 56% acetyl groups) is suitable for thermoplastic processing. With appropriate plasticizers a plastic material is obtained which excels in transparency and pleasant texture, and it is therefore often used for tool handles, combs, spectacle frames, and the like. In principle, cellulose acetate with such a degree of substitution is

Alexander Ach

1993-01-01

212

21 CFR 582.1005 - Acetic acid.  

Code of Federal Regulations, 2012 CFR

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...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED... § 582.1005 Acetic acid. (a) Product....

2012-04-01

213

21 CFR 582.1005 - Acetic acid.  

Code of Federal Regulations, 2013 CFR

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...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED... § 582.1005 Acetic acid. (a) Product....

2013-04-01

214

21 CFR 582.1005 - Acetic acid.  

Code of Federal Regulations, 2011 CFR

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...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED... § 582.1005 Acetic acid. (a) Product....

2011-04-01

215

21 CFR 582.1005 - Acetic acid.  

Code of Federal Regulations, 2010 CFR

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...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED... § 582.1005 Acetic acid. (a) Product....

2010-04-01

216

21 CFR 582.1005 - Acetic acid.  

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...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED... § 582.1005 Acetic acid. (a) Product....

2014-04-01

217

Manufacturing Ethyl Acetate From Fermentation Ethanol  

NASA Technical Reports Server (NTRS)

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.

Rohatgi, Naresh K.; Ingham, John D.

1991-01-01

218

Electrophoretic extraction of proteins from two-dimensional electrophoresis gel spots  

DOEpatents

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.

Zhang, Jian-Shi; Giometti, C.S.; Tollaksen, S.L.

1987-09-04

219

Membrane stabilizer  

DOEpatents

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.

Mingenbach, W.A.

1988-02-09

220

Scanning electrochemical microscopy as a readout tool for protein electrophoresis.  

PubMed

Scanning electrochemical microscopy (SECM) was used to image silver-stained proteins on a poly(vinylidene difluoride) membrane. The method is based on measuring the current at a scanning microelectrode in the feedback mode. The electrochemical feedback is caused by the redox-mediated etching of the isolated 5 - 10-nm-diameter silver nanoparticles formed during the staining process. Several parameters, such as the redox mediator and the staining protocol, were optimized to ensure a high resolution and a low detection limit, i.e., 0.5 ng of bovine serum albumin (4 x 10(-14) mol) distributed on an area of 1 mm(2) (4 x 10(-16) mol x cm(-2)). Images of beta-lactoglobulin A and myoglobin bands after gel electrophoretic separation and electroblotting were obtained in order to demonstrate that SECM can be employed as a sensitive and quantitative readout method for detection of proteins after gel electrophoresis. An additional advantage is that the silver staining can be removed, allowing further downstream mass spectrometry analysis. PMID:17539601

Zhang, Meiqin; Wittstock, Gunther; Shao, Yuanhua; Girault, Hubert H

2007-07-01

221

The fluid mechanics of continuous flow electrophoresis  

NASA Technical Reports Server (NTRS)

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.

Saville, D. A.

1990-01-01

222

Characterization of protein conjugates using capillary electrophoresis.  

PubMed

With the aim of generating antibodies, a calix[4]arene-crown-6 was coupled to bovine serum albumin. For that purpose, a complete procedure to optimize and characterize the coupling of hydrophobic haptens based on capillary electrophoresis (CE) was developed. We demonstrated the existence of a polynomial relationship between the electrophoretic mobility (mu(ep)) and the hapten density. This correlation was used not only to study the coupling reaction in terms of optimization and kinetics but also to determine the average coupling molar ratio of any given conjugate. An estimation of the heterogeneity of these conjugates by simulation of experimental peaks was also proposed. PMID:17964582

Safi, Samir; Asfari, Zouhair; Hagège, Agnès

2007-11-30

223

Biotechnology Laboratory: Gel Electrophoresis of Dyes  

NSDL National Science Digital Library

A portion of the Partnership for Plant Genomics Education, hosted by the University of California-Davis, this PDF presents a student activity where students will use agarose gel electrophoresis to separate several different dyes. The lab is described as a âÂÂprecursor to DNA separationsâ and thus provides an important step in the subject matter. The lab provides for students: detailed instructions, background information, and a quiz and group questions. Answers to the questions, and also the general objective of the lab, are provided for the instructor. Overall, the lab is introductory in nature and perfect for any science classroom.

2008-12-05

224

A Single-Sample Method for Determination of Carbohydrate and Protein Contents Glycoprotein Bands Separated by Sodium Dodecyl Sulfate– Polyacrylamide Gel Electrophoresis  

Microsoft Academic Search

A method is described for determination of carbohydrate and protein contents of glycoproteins separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and then electroblotted onto polyvinylidene difluoride (PVDF) membranes. Blots were stained, and appropriate pieces of PVDF membranes were excised, destained, and subjected to sequential hydrolysis with 0.2 M trifluoroacetic acid (TFA) for 1 h at 80°C, then with 2 M

Ewa Zdebska; Jerzy Ko?cielak

1999-01-01

225

Effect of iodination on human growth hormone and prolactin: characterized by bioassay, radioimmunoassay, radioreceptor assay, and electrophoresis  

Microsoft Academic Search

Human GH (hGH) and PRL (hPRL) were iodinated using lactoperoxidase. The iodinated hormones were characterized by RIA, radioreceptor assay (RRA), and bioassay (BA) using the Nb2 Node lymphoma cell line. The proportion of tracer that could bind to rat liver membranes or rabbit antibodies was determined, and the distribution of iodinated hormones was examined using polyacrylamide gel electrophoresis. Excess antibody

J. P. Hughes; T. Tanaka; P. W. Gout; C. T. Beer; R. L. Noble; H. G. Friesen

1982-01-01

226

Isolation and partial characterization of Borrelia burgdorferi inner and outer membranes by using isopycnic centrifugation.  

PubMed Central

In order to characterize the protein composition of the outer membrane of Borrelia burgdorferi, we have isolated inner and outer membranes by using discontinuous sucrose density step gradients. Outer and inner membrane fractions isolated by this method contained less than 1 and 2%, respectively, of the total lactate dehydrogenase activity (soluble marker) in cell lysate. More importantly, the purified outer membranes contained less than 4% contamination by the C subunit of F1/F0 ATPase (inner membrane marker). Very little flagellin protein was present in the outer membrane sample. This indicated that the outer membranes were relatively free of contamination by cytoplasmic, inner membrane or flagellar components. The outer membrane fractions (rho = 1.19 g/cm3) contained 0.15 mg (dry weight) of protein per mg. Inner membrane samples (rho = 1.12 g/cm3) contained 0.60 mg (dry weight) of protein per mg. Freeze-fracture electron microscopy revealed that the outer membrane vesicles contained about 1,700 intramembranous particles per micron 2 while inner membrane densities for inner and outer membranes. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and nonequilibrium pH gel electrophoresis-SDS-PAGE analyses of inner and outer membrane samples revealed several proteins unique to the inner membrane and 20 proteins that localized specifically to the outer membrane. This analysis clearly shows that the inner and outer membranes isolated by this technique are unique structures. Images PMID:8002566

Bledsoe, H A; Carroll, J A; Whelchel, T R; Farmer, M A; Dorward, D W; Gherardini, F C

1994-01-01

227

[Electronic microscopy in endodontic electrophoresis efficiency assessment].  

PubMed

The reason for insufficient efficiency of endodontic treatments is a complex structure of root canals system and presence of dentine tubules (DT) in a root dentine. For sterilization and obturation of all spaces in a root canal system the method of cupper-calcium hydroxide (CCH) electrophoresis was developed. The authors proposed more effective method of CCH galvanophoresis by means of galvanic pins based on electrophoresis principles but allowing deep impregnation of the root dentine by nanoparticles of CCH. The purpose of the study was to validate the parameters of root dentine nanoimpregnation by CCH at endodontic galvanophoresis. Material and methods. Research has carried out on 24 removed teeth in laboratory model. The impact of irrigation of root canal and nanoimpregnation duration on the microflora, dentine smear layer, depth of penetration of CCH particles in dentine tubules was studied by scanning electronic microscopy. Results. Irrigation of root canals essentially reduces the amount of microorganisms and eliminates the dentine smear layer. Nanoimpregnation of root dentine by CCH for 1 day results in obtuation of 60-70% of DT up to 100-200 nm, for 1 week - promotes uniform obturation of DT to 35-50 microns. These values proves galvanophoresis to be a useful tool for pulpitis treatment. By nanoimpregnation for 2 weeks DT were filled with nanoparticles of CCH on depth up to 1.2-1.5 mm, and for 4 weeks - up to 2.5 mm. These terms can be recommended for treatment of apical periodontitis. PMID:23715442

Rumiantsev, V A; Rodionova, E G; Denis, A G; Ol'khovskaia, A V; Tsaturova, Iu V

2013-01-01

228

Mating receptor complex in the flagellar membrane of Chlamydomonas eugametos gametes  

Microsoft Academic Search

The protein composition of the flagellar membrane of C. eugametos mt-gametes was analyzed using SDS-polyacrylamide gel electrophoresis. The association of the proteins with the membrane was assessed by differential extraction and an assay for glycosylation. Particular attention was paid to integral membrane proteins that could be associated with the mt- agglutinin, the membrane-bound sexual receptor by which the mt- gamete

H. W. Kalshoven; A. Musgrave; H. Ende

1990-01-01

229

Separation and determination of homologues of linear alkylbenzenesulfonates by nonaqueous capillary zone electrophoresis using alkylammonium salts in ethanol.  

PubMed

The separation of linear alkylbenzene sulfonates (LAS) by nonaqueous capillary electrophoresis (NACE) using negative polarity, and a buffer containing acetic acid and an alkylamine in nonaqueous ethanol, has been investigated. Several primary, secondary, and tertiary alkylamines with alkyl chains of different length were compared. The solutes travelled against the electroosmotic flow (EOF), and at the same time were braked by association with the alkylamine molecules or with the alkylammonium ions. The best resolution between adjacent LAS homologues (R approximately 2.1), partial isomer resolution in two peaks, and at the same time an excellent repeatability, was obtained with a small dipentylamine excess over the acetic acid. When the buffer concentration increased, resolution between the homologues increased slightly (R approximately 2.4), and a different isomer group was partially separated. A background electrolyte (BGE) containing 10 mM acetic acid and 20 mM dipentylamine to separate and quantify the homologues within 25 min is recommended. The isomer peak profile with up to three peaks can be estimated using this buffer and another one with 80 mM acetic acid and 90 mM dipentylamine. The former BGE was used to determine LAS in liquid and powder laundry detergents. The detection limit for the determination of total LAS in these products was 2.5 microg mL(-1), and the peak area and migration time interday repeatabilities were below 4.3 and 2.8%, respectively. PMID:11465501

Herrero-Martínez, J M; Simó-Alfonso, E F; Ramis-Ramos, G

2001-06-01

230

21 CFR 584.200 - Ethyl alcohol containing ethyl acetate.  

...2014-04-01 2014-04-01 false Ethyl alcohol containing ethyl acetate. 584.200...Affirmed as GRAS § 584.200 Ethyl alcohol containing ethyl acetate. The feed additive ethyl alcohol containing ethyl acetate meets the...

2014-04-01

231

Correlation between acetic acid resistance and characteristics of PQQ-dependent ADH in acetic acid bacteria.  

PubMed

In this study, we compared the growth properties and molecular characteristics of pyrroloquinoline quinone (PQQ)-dependent alcohol dehydrogenase (ADH) among highly acetic acid-resistant strains of acetic acid bacteria. Gluconacetobacter europaeus exhibited the highest resistance to acetic acid (10%), whereas Gluconacetobacter intermedius and Acetobacter pasteurianus resisted up to 6% of acetic acid. In media with different concentrations of acetic acid, the maximal acetic acid production rate of Ga. europaeus slowly increased, but specific growth rates decreased concomitant with increased concentration of acetic acid in medium. The lag phase of A. pasteurianus was twice and four times longer in comparison to the lag phases of Ga. europaeus and Ga. intermedius, respectively. PQQ-dependent ADH activity was twice as high in Ga. europaeus and Ga. intermedius as in A. pasteurinus. The purified enzymes showed almost the same specific activity to each other, but in the presence of acetic acid, the enzyme activity decreased faster in A. pasteurianus and Ga. intermedius than in Ga. europaeus. These results suggest that high ADH activity in the Ga. europaeus cells and high acetic acid stability of the purified enzyme represent two of the unique features that enable this species to grow and stay metabolically active at extremely high concentrations of acetic acid. PMID:16133326

Trcek, Janja; Toyama, Hirohide; Czuba, Jerzy; Misiewicz, Anna; Matsushita, Kazunobu

2006-04-01

232

Membrane tethering  

PubMed Central

Membrane trafficking depends on transport vesicles and carriers docking and fusing with the target organelle for the delivery of cargo. Membrane tethers and small guanosine triphosphatases (GTPases) mediate the docking of transport vesicles/carriers to enhance the efficiency of the subsequent SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor)-mediated fusion event with the target membrane bilayer. Different classes of membrane tethers and their specific intracellular location throughout the endomembrane system are now well defined. Recent biochemical and structural studies have led to a deeper understanding of the mechanism by which membrane tethers mediate docking of membrane carriers as well as an appreciation of the role of tethers in coordinating the correct SNARE complex and in regulating the organization of membrane compartments. This review will summarize the properties and roles of membrane tethers of both secretory and endocytic systems. PMID:25343031

Chia, Pei Zhi Cheryl

2014-01-01

233

Investigating Membranes  

NSDL National Science Digital Library

While not organic in nature, quick-"growing" artificial membranes can be a profound visual aid when teaching students about cellular processes and the chemical nature of membranes. Students are often intrigued when they see biological and chemical concept

Mccallister, Gary; Zrelak, Yoshi

2009-09-01

234

Diagnostic value of alkaline phosphatase isoenzyme separation by affinity electrophoresis in the dog.  

PubMed Central

Affinity electrophoresis, using wheat germ lectin, was used to separate the alkaline phosphatase isoenzymes in the sera of 150 dogs with alkaline phosphatase values greater than or equal to 150 IU/L. The method provided clearer separation of the liver, bone and steroid-induced alkaline phosphatase isoenzymes commonly observed in canine serum, compared to conventional cellulose acetate electrophoresis. The dogs were divided into four patient groups determined by previous corticosteroid treatment, evidence of elevated endogenous corticosteroid levels, age and alanine aminotransferase values. The isoenzyme pattern of each patient was qualitatively assessed. The isoenzyme pattern most frequently observed was greater than 50% steroid induced alkaline phosphatase, which was present in 76 of 150 dogs. This pattern was observed in 18 of 22 dogs receiving corticosteroid therapy, two of three dogs with hyperadrenocorticism, and in dogs with a variety of other diagnoses. The majority of immature dogs (12 of 20) had an isoenzyme pattern consisting of greater than 50% bone. The majority of dogs with active hepatocellular injury (16 of 27) had greater than 50% liver isoenzyme. The isoenzyme pattern was not specific for certain diseases, therefore the diagnostic usefulness is limited. However the isoenzyme result is useful in some cases to determine which further diagnostic tests are indicated, and to determine the source of alkaline phosphatase elevation. Images Fig. 1. PMID:3349387

Kidney, B A; Jackson, M L

1988-01-01

235

Potential problems in serum protein electrophoresis.  

PubMed

Potential problems are described that one could encounter in carrying out an electrophoretic procedure including its ancillary phases of visualization (staining) and quantification (densitometry). Endpoint-like measurements for separated isoenzymes may provide artifactual kinetic values as well, because stain measurement is fixed at a single time whereas reagent blanking in the electrophoretic medium is substituted for the conventional serum initial absorbance readings of test-tube determinations. Truncation of separated electrophoretic zones or opacity of an electrophoretic anti-convection medium such as uncleared cellulose acetate may also interfere with absolute quantification procedures. PMID:2427271

Artiss, J D; Epstein, E; Kiechle, F L; Zak, B

1986-09-01

236

Novel absorption detection techniques for capillary electrophoresis  

SciTech Connect

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 {mu}M 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.

Xue, Y.

1994-07-27

237

Combined electrophoresis-electrospray interface and method  

DOEpatents

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.

Smith, Richard D. [Richland, WA; Udseth, Harold R. [Richland, WA; Olivares, Jose A. [Los Alamos, NM

1994-10-18

238

Combined electrophoresis-electrospray interface and method  

DOEpatents

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.

Smith, R.P.; Udseth, H.R.; Olivares, J.A.

1989-12-05

239

Combined electrophoresis-electrospray interface and method  

DOEpatents

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.

Smith, Richard P. (Richland, WA); Udseth, Harold R. (Richland, WA); Olivares, Jose A. (North Augusta, SC)

1989-01-01

240

Combined electrophoresis-electrospray interface and method  

DOEpatents

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.

Smith, R.D.; Udseth, H.R.; Olivares, J.A.

1994-10-18

241

Dating silk by capillary electrophoresis mass spectrometry.  

PubMed

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 ?g 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. PMID:21913691

Moini, Mehdi; Klauenberg, Kathryn; Ballard, Mary

2011-10-01

242

Acetic acid fermentation of acetobacter pasteurianus: relationship between acetic acid resistance and pellicle polysaccharide formation.  

PubMed

Acetobacter pasteurianus strains IFO3283, SKU1108, and MSU10 were grown under acetic acid fermentation conditions, and their growth behavior was examined together with their capacity for acetic acid resistance and pellicle formation. In the fermentation process, the cells became aggregated and covered by amorphous materials in the late-log and stationary phases, but dispersed again in the second growth phase (due to overoxidation). The morphological change in the cells was accompanied by changes in sugar contents, which might be related to pellicle polysaccharide formation. To determine the relationship between pellicle formation and acetic acid resistance, a pellicle-forming R strain and a non-forming S strain were isolated, and their fermentation ability and acetic acid diffusion activity were compared. The results suggest that pellicle formation is directly related to acetic acid resistance ability, and thus is important to acetic acid fermentation in these A. pasteurianus strains. PMID:20699583

Kanchanarach, Watchara; Theeragool, Gunjana; Inoue, Taketo; Yakushi, Toshiharu; Adachi, Osao; Matsushita, Kazunobu

2010-01-01

243

Two-dimensional Gel Electrophoresis (2DE)  

NASA Astrophysics Data System (ADS)

The chemical compounds, which are present in the environment, increasingly cause bad effects on health. The most serious effects are tumors and various mutations at the cellular level. Such compounds, from the analytical point of view, can serve the function of biomarkers, constituting measurable changes in the organism's cells and biochemical processes occurring therein. The challenge of the twenty-first century is therefore searching for effective and reliable methods of identification of biomarkers as well as understanding bodily functions, which occur in living organisms at the molecular level. The irreplaceable tool for these examinations is proteomics, which includes both quality and quantity analysis of proteins composition, and also makes it possible to learn their functions and expressions. The success of proteomics examinations lies in the usage of innovative analytical techniques, such as electromigration technique, two-dimensional electrophoresis in polyacrylamide gel (2D PAGE), liquid chromatography, together with high resolution mass spectrometry and bio-informatical data analysis. Proteomics joins together a number of techniques used for analysis of hundreds or thousands of proteins. Its main task is not the examination of proteins inside the particular tissue but searching for the differences in the proteins' profile between bad and healthy tissues. These differences can tell us a lot regarding the cause of the sickness as well as its consequences. For instance, using the proteomics analysis it is possible to find relatively fast new biomarkers of tumor diseases, which in the future will be used for both screening and foreseeing the course of illness. In this chapter we focus on two-dimensional electrophoresis because as it seems, it may be of enormous importance when searching for biomarkers of cancer diseases.

K?odzi?ska, Ewa; Buszewski, Bogus?aw

244

Fluorescence quenching of etilefrine by acetate anion  

NASA Astrophysics Data System (ADS)

Acid dissociation in the excited state of antihypotensor drug etilefrine [2-(ethylamino1-3-hydroxyphenyl)ethanol] is studied. Fluorescence of etilefrine decreases at pH<7 and is related to phenolic group dissociation. However, intensity of etilefrine fluorescence diminishes as the concentration of the acetate anion increases at pH>7. Analyses of the absorption and fluorescence spectra of aqueous solutions of etilefrine in the presence of acetate anions have been made. Considering the existence of an equilibrium in the excited state the values of 3.47×10 -9 and 0.216×10 -9 M -1 s -1 have been obtained for the rate constants for direct and inverse reactions, respectively. Moreover, the lifetime ( ?0'=0.58×10 -9 s) and quantum yield (0.01) of non-protonated etilefrine have been determined. Our results seem to support the existence of a dynamic quenching process based on a proton transfer mechanism induced by acetate anions. This process could represent a serious inconvenience in analytical fluorimetric techniques taking into account that the acetic acid/acetate pair is commonly used as a buffer. Additional fluorescence quenching by H + ions could be involved in acid aqueous mediums. At high concentrations of acetic acid, a value of 2.98×10 -9 M -1 s -1 for the bimolecular constant for the quenching by H + has been calculated.

Quintero Osso, B.; Carazo Rodríguez, F. M.; Morales Domingo, J. J.; Cabeza González, M. C.; Thomas Gómez, J.

1999-02-01

245

Acetate limitation and nitrite accumulation during denitrification  

SciTech Connect

Nitrite accumulated in denitrifying activated sludge mixed liquor when the carbon and electron source, acetate, was limited. If acetate was added to obtain a carbon-to-nitrogen (C:N) ratio in the range of 2:1 to 3:1, nitrate was completely consumed at the same rate with no nitrite accumulation, indicating that nitrate concentration controlled the respiration rate as long as sufficient substrate was present. However, when acetate was reduced to a C:N ratio of 1:1, while nitrate continued to be consumed, > 50% of the initial nitrate-nitrogen accumulated as nitrite and 29% persisted as nitrite throughout an endogenous denitrification period of 8--9 h. While nitrite accumulated during acetate-limited denitrification, the specific nitrate reduction rate increased significantly compared with the rate when excess acetate was provided as follows: 0.034 mg-NO{sub 3}-N/mg-mixed liquid volatile suspended solids/h versus 0.023 mg-NO{sub 3}-N/mg-mixed liquid volatile suspended solids/h, respective. This may be explained by nitrate respiration out-competing nitrite respiration for limited acetate electrons. Complete restoration of balanced denitrification and elimination of nitrite accumulation during denitrification required several weeks after the C:N ratio was increased back to 2:1.

Oh, J. [Pohang Univ. of Science and Technology (Korea, Republic of). School of Environmental Engineering] [Pohang Univ. of Science and Technology (Korea, Republic of). School of Environmental Engineering; Silverstein, J. [Univ. of Colorado, Boulder, CO (United States)] [Univ. of Colorado, Boulder, CO (United States)

1999-03-01

246

Protein fouling of surface-modified polymeric microfiltration membranes  

Microsoft Academic Search

The effects of varying morphology and surface chemistry on protein fouling of microfiltration membranes were investigated. In part I of the study, on the effects of varying morphology, results show that 0.2 ?m track-etched polycarbonate (PC) membranes internally foul, with external fouling becoming the dominant means of fouling only at later times. A 0.2 ?m cellulose acetate (CA) membrane showed

Jeffrey Mueller; Robert H. Davis

1996-01-01

247

Activating membranes  

E-print Network

We present a general dynamical theory of a membrane coupled to an actin cortex containing polymerizing filaments with active stresses and currents, and demonstrate that active membrane dynamics [Phys. Rev. Lett \\textbf{84}, 3494 (2000)] and spontaneous shape oscillations emerge from this description. We also consider membrane instabilities and patterns induced by the presence of filaments with polar orientational correlations in the tangent plane of the membrane. The dynamical features we predict should be seen in a variety of cellular contexts involving the dynamics of the membrane-cytoskeleton composite and cytoskeletal extracts coupled to synthetic vesicles.

Ananyo Maitra; Pragya Srivastava; Madan Rao; Sriram Ramaswamy

2013-11-20

248

Activating Membranes  

NASA Astrophysics Data System (ADS)

We present a general dynamical theory of a membrane coupled to an actin cortex containing polymerizing filaments with active stresses and currents, and demonstrate that active membrane dynamics [S. Ramaswamy et al., Phys. Rev. Lett. 84, 3494 (2000)] and spontaneous shape oscillations emerge from this description. We also consider membrane instabilities and patterns induced by the presence of filaments with polar orientational correlations in the tangent plane of the membrane. The dynamical features we predict should be seen in a variety of cellular contexts involving the dynamics of the membrane-cytoskeleton composite and cytoskeletal extracts coupled to synthetic vesicles.

Maitra, Ananyo; Srivastava, Pragya; Rao, Madan; Ramaswamy, Sriram

2014-06-01

249

Capillary Electrophoresis of Water-Soluble Vitamins: An Undergraduate Experiment  

Microsoft Academic Search

Capillary electrophoresis (CE) is a relatively new analytical separation technique that is not usually introduced in the undergraduate analytical chemistry curriculum. The technique's growing popularity in research, industrial, and commercial laboratories, however, should be a reason to consider its introduction at this level. Here, we describe an exercise utilizing capillary zone electrophoresis and micellar electrokinetic chromatography. This exercise provides a

Victòria Salvadó; Juan M. Sánchez

2002-01-01

250

Capillary Electrophoresis of Water-Soluble Vitamins: An Undergraduate Experiment  

Microsoft Academic Search

Capillary electrophoresis (CE) is a relatively new analytical separation technique that is not usually introduced in the undergraduate analytical chemistry curriculum. The technique’s growing popularity in research, industrial, and commercial laboratories, however, should be a reason to consider its introduction at this level. Here, we describe an exercise utilizing capillary zone electrophoresis and micellar electrokinetic chromatography. This exercise provides a

Victòria Salvadó; Juan M. Sánchez

2002-01-01

251

Electrophoresis 2012, 33, 599606 599 Rossella Gottardo1  

E-print Network

.1002/elps.201100383 1 Introduction In forensic toxicology, capillary electrophoresis (CE), after more than, Unit of Forensic Medicine, University of Verona, Verona, Italy 2Institute of Physiology, Academy Article Analysis of drugs of forensic interest with capillary zone electrophoresis/time-of-flight mass

Miksik, Ivan

252

Joule heating effects on peak broadening in capillary zone electrophoresis  

Microsoft Academic Search

Based on Taylor-Aris dispersion theory, a general analytical formula was derived for the theoretical plate height in capillary zone electrophoresis with the consideration of Joule heating effects. During the electrophoresis, the Joule heating causes a temperature rise and temperature gradients in the buffer solution. The temperature variations can affect the molecular diffusion, electroosmotic flow and electrophoretic flow via the temperature-dependent

Xiangchun Xuan; Dongqing Li

2004-01-01

253

Evaluation of protocols used in 2-d electrophoresis for proteome analysis of young rice caryopsis.  

PubMed

In order to obtain a high-resolution electrophorogram of rice young panicle proteome, we evaluated various protocols commonly used in two-dimensional (2D) polyacrylamide gel electrophoresis (PAGE) of proteins, including gel staining protocol, pH range of immobilized pH gradient (IPG) strips and sample loading quantity. Results showed that a silver staining protocol using sensitized solution containing glacial acetic acid, sodium acetate and sodium thiosulfate (reported by Heukeshoven and Dernick in 1988) and a Coomassie Brilliant Blue staining method using solution containing G-250, ammonium sulfate and phosphoric acid (reported by Pink et al in 2010) demonstrated the superior staining effect. In addition, we also showed that higher resolution was achieved when IPG gel strip with pH range of 5-8 was used, compared to that with pH range of 4-7. Finally, the optimal loading quantity was determined as 130 ?g using the 17 cm-long nonlinear IPG strip with pH 5-8 in combination with the silver nitrate staining protocol. The evaluated results would be helpful in proteome analysis of young rice caryopsis. PMID:22289479

Liao, Jiang-Lin; Huang, Ying-Jin

2011-12-01

254

Determination of the diol content of chromatographic supports by capillary electrophoresis.  

PubMed

A capillary electrophoresis (CE) method was developed for determining the diol content of supports used in high-performance affinity or size exclusion chromatography. This method involved oxidizing the diol-bonded support with periodate, followed by the use of CE to separate and quantitate the iodate produced by this reaction. Both the oxidation and separation conditions were considered in optimizing this assay. The final method was performed by reacting a known amount of support with a 20-fold excess of periodate in pH 4.0, 0.5 M acetate buffer, with pyromellitic acid being used as an internal standard. After allowing 5-10 min for oxidation, the mixture was filtered and the filtrate was injected onto a 57 cm x 50 microns I.D. fused-silica capillary operated at 25 kV and containing pH 4.0, 0.5 M acetate as the running buffer. The total separation time was 5 min per run and gave a detection limit of 0.1 mM iodate (or 0.1 mumol diol groups) for a 6-nl injection of a 1-ml reaction mixture. By varying the amount the support that was assayed, this method could be used with either porous or non-porous supports. This technique showed good correlation with an iodometric titration but required much less sample and time to perform. PMID:9042737

Chattopadhyay, A; Hage, D S

1997-01-17

255

Membrane Extraction for Detoxification of Biomass Hydrolysates  

SciTech Connect

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.

Grzenia, D. L.; Schell, D. J.; Wickramasinghe, S. R.

2012-05-01

256

Androgen dynamics in vitro in the human prostate gland. Effect of cyproterone and cyproterone acetate  

PubMed Central

Hyperplastic and adenocarcinomatous human prostatic tissue was superfused in vitro with radioactively labelled androst-4-ene-3,17-dione, testosterone and 5?-dihydrotestosterone (17?-hydroxy-5?-androstan-3-one), with and without addition of the anti-androgens cyproterone and cyproterone acetate. Cyproterone competitively inhibited the entry of the androgens into the majority of the tissues, whereas cyproterone acetate increased this entry. These findings indicated that transport of androstenedione, testosterone and 5?-dihydrotestosterone into prostatic tissue is performed by a specific mechanism, possibly involving a carrier situated in the cell membrane. The extent of metabolism of the three androgens was also modified: formation of 5?-dihydrotestosterone from testosterone, and of the latter from androstenedione, was decreased by cyproterone and increased by the acetate. Acetate was more effective than cyproterone in decreasing the `uptake' of the perfused androgens by the tissue; at the same time, it increased the androgen clearance from the tissue. As cyproterone acetate is the more potent of the two anti-androgens, the possibility that these findings in vitro are related to the different anti-androgenic potency exhibited by the two compounds in vivo is discussed. `Uptake' of the two anti-androgens and the response to their action on androgen dynamics were similar in adenocarcinomatous and hyperplastic glands. PMID:4125095

Giorgi, Eleonora P.; Shirley, I. M.; Grant, J. K.; Stewart, Joan C.

1973-01-01

257

Effect of membrane splitting on transmembrane polypeptides  

PubMed Central

We investigated the effect of membrane splitting on the primary structure of human erythrocyte membrane polypeptides. Monolayers of intact, chemically unmodified cells were freeze-fractured and examined by one-dimensional SDS PAGE. Silver-stained gels revealed all major polypeptides that stain with Coomassie Blue as well as all bands that stain with periodic acid Schiff's reagent. Both nonglycosylated and glycosylated membrane polypeptides could be detected at concentrations of only a few nanograms per band. Membrane splitting had no effect on the position or number of bands. Monolayers of intact erythrocytes that had been enzymatically radioiodinated with lactoperoxidase were examined by electrophoresis, fluorography, and liquid scintillation counting. Radioactivity was quantified before and after monolayer formation and splitting, and at several stages of gel staining, drying, and fluorography. Although overexposed fluorographs revealed several minor radioiodinated bands in addition to band 3 and the glycophorins, no new bands were detected in split membrane samples derived from intact cells. These observations support the conclusion that neither the band 3 anion channel nor the glycophorin sialoglycoproteins are fragmented during freeze-fracturing. Although both band 3 and glycophorin partition to the cytoplasmic side of the membrane, preliminary quantitative observations suggest an enrichment of glycophorin in the split extracellular "half" membrane. We conclude that the process of membrane splitting by planar monolayer freeze- fracture does not cleave the covalent polypeptide backbone of any erythrocyte membrane protein, peripheral or integral. PMID:3944190

1986-01-01

258

Removal of soluble COD by a biofilm formed on a membrane in a jet loop type membrane bioreactor  

Microsoft Academic Search

The soluble chemical oxygen demand (COD) removal efficiency through a cake layer (biofilm) deposited on the surfaces of a membrane was investigated as a function of biofilm thickness in a jet loop type membrane bioreactor (JL-MBR). The mechanisms for the removal were investigated based on the microbial characteristics of the biofilm.Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was used to

Jong-Sang Park; Chung-Hak Lee

2005-01-01

259

Acetate transport and utilization in the rat brain.  

PubMed

Acetate, a glial-specific substrate, is an attractive alternative to glucose for the study of neuronal-glial interactions. The present study investigates the kinetics of acetate uptake and utilization in the rat brain in vivo during infusion of [2-13C]acetate using NMR spectroscopy. When plasma acetate concentration was increased, the rate of brain acetate utilization (CMR(ace)) increased progressively and reached close to saturation for plasma acetate concentration > 2-3 mM, whereas brain acetate concentration continued to increase. The Michaelis-Menten constant for brain acetate utilization (K(M)(util) = 0.01 +/- 0.14 mM) was much smaller than for acetate transport through the blood-brain barrier (BBB) (K(M)(t) = 4.18 +/- 0.83 mM). The maximum transport capacity of acetate through the BBB (V(max)(t) = 0.96 +/- 0.18 micromol/g/min) was nearly twofold higher than the maximum rate of brain acetate utilization (V(max)(util) = 0.50 +/- 0.08 micromol/g/min). We conclude that, under our experimental conditions, brain acetate utilization is saturated when plasma acetate concentrations increase above 2-3 mM. At such high plasma acetate concentration, the rate-limiting step for glial acetate metabolism is not the BBB, but occurs after entry of acetate into the brain. PMID:19393008

Deelchand, Dinesh K; Shestov, Alexander A; Koski, Dee M; U?urbil, Kâmil; Henry, Pierre-Gilles

2009-05-01

260

Acetate and hypercalciuria during total parenteral nutrition13  

Microsoft Academic Search

Hypercalciuria and negative calcium balance are complications oftotal par- enteral nutrition (TPN). Because metabolism ofthe TPN formula generates an acid load that can induce hypercalciuria, we evaluated the effect ofsupplementing the formula with acetate. In a randomized crossover study six patients on continuous and six on cyclic TPN received no added acetate or 160 mmol acetate\\/d replacing 160 mmol chloride\\/d

Charles H Berkelhammer; Richard J Wood; Michael D Sitrin

261

Acetate reduces microglia inflammatory signaling in vitro  

PubMed Central

Acetate supplementation increases brain acetyl-CoA and histone acetylation and reduces lipopolysaccharide (LPS)-induced neuroglial activation and interleukin (IL)-1? expression in vivo. To determine how acetate imparts these properties, we tested the hypothesis that acetate metabolism reduces inflammatory signaling in microglia. To test this, we measured the effect acetate treatment had on cytokine expression, mitogen-activated protein kinase (MAPK) signaling, histone H3 at lysine 9 acetylation, and alterations of nuclear factor-kappa B (NF-?B) in primary and BV-2 cultured microglia. We found that treatment induced H3K9 hyperacetylation and reversed LPS-induced H3K9 hypoacetylation similar to that found in vivo. LPS also increased IL-1?, IL-6 and tumor necrosis factor-alpha (TNF-?) mRNA and protein, while treatment returned the protein to control levels and only partially attenuated IL-6 mRNA. In contrast, treatment increased mRNA levels of transforming-growth factor-?1 (TGF-?1) and both IL-4 mRNA and protein. LPS increased p38 MAPK and JNK phosphorylation at 4 and 2–4 hr respectively, while treatment reduced p38 MAPK and JNK phosphorylation only at 2 hr. In addition, treatment reversed the LPS-induced elevation of NF-?B p65 protein and phosphorylation at serine 468 and induced acetylation at lysine 310. These data suggest that acetate metabolism reduces inflammatory signaling and alters histone and non-histone protein acetylation. PMID:22924711

Soliman, Mahmoud L.; Puig, Kendra L.; Combs, Colin K.; Rosenberger, Thad A.

2012-01-01

262

The behaviour of tungsten electrodes in a mixture of acetic acid and acetic anhydride  

Microsoft Academic Search

Summary Tungsten electrodes have advantageously been used for potentiometric end-point detection in perchloric acid titration of bases in a mixture of acetic acid and acetic anhydride. They have also given good results in biamperometric detection of the equivalence point in continuous coulometric titration of small quantities of bases and acids in the same solvent. Tungsten electrodes in the presence of

Tibor J. Pastor; Vilim J. Vajgand

1976-01-01

263

Charged membranes.  

PubMed

This Teaching Resource provides three animated lessons that describe the storage and utilization of energy across plasma membranes. The "Na,K ATPase" animation explains how these pumps establish the electrochemical gradient that stores energy across plasma membranes. The "ATP synthesizing complexes" animation shows how these complexes transfer energy from the inner mitochondrial membrane to adenosine triphosphate (ATP). The "action potential" lesson explains how charged membranes are used to propagate signals along the axons of neurons. These animations serve as valuable resources for any collegiate-level course that describes these important factors. Courses that might employ them include introductory biology, biochemistry, biophysics, cell biology, pharmacology, and physiology. PMID:23592845

Thatcher, Jack D

2013-01-01

264

Investigations of the inhibitory effects of tocopherol (vitamin E) on free radical deterioration of cellular membranes  

NASA Technical Reports Server (NTRS)

The inhibitory effects are investigated of d,1-alpha-tocopherol and d,1-alpha-tocopheryl acetate on the free radical deterioration of cellular membranes. The level of toxicity of d,1-alpha-tocopherol and d,1-alpha-tocopheryl acetate in mice is determined.

Richardson, D.

1975-01-01

265

Analysis of metallothionein by capillary electrophoresis.  

PubMed

Metallothioneins (MTs) belong to proteins playing a key role in metal ion homeostasis, maintenance of the redox pool and free radical scavenging in both prokaryotic and eukaryotic cells. Strong interactions of the MTs with essential and non-essential metal ions as well as unique MT structure and behavior under various conditions are subjects of numerous studies. Among other analytical techniques, capillary electrophoresis (CE) has been proven to be an effective tool not only for determination of MT in biological samples, but also for the identification of its isoforms and sub-isoforms in various types of samples. Moreover, CE has a great potential to investigate MT-metal and MT-protein interactions, which has not been fully utilized yet. Thus, it is not surprising that numerous studies devoted to the optimization of CE conditions such as background electrolyte composition, electrolyte modifiers and/or capillary surface modifications have been carried out since MT's discovery in 1957. From the MTs' detection point of view, optical detectors including absorbance, laser-induced fluorescence have been employed. Also mass spectrometric detection coupled to the various ionization techniques including inductively coupled plasma (ICP) and electrospray ionization (ESI) has been utilized for detail MT characterization and sensitive determination. In this paper, articles published from eighties to 2011 are reviewed, presenting both optimization of key parameters of CE method for MT determination as well as utilization of CE as a routine analytical technique for further investigation of complex biological and biochemical processes where MT is a key component. PMID:22036087

Ryvolova, Marketa; Adam, Vojtech; Kizek, Rene

2012-02-24

266

Recovering/concentrating of hemicellulosic sugars and acetic acid by nanofiltration and reverse osmosis from prehydrolysis liquor of kraft based hardwood dissolving pulp process.  

PubMed

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. PMID:24434701

Ahsan, Laboni; Jahan, M Sarwar; Ni, Yonghao

2014-03-01

267

Extended length microchannels for high density high throughput electrophoresis systems  

DOEpatents

High throughput electrophoresis systems which provide extended well-to-read distances on smaller substrates, thus compacting the overall systems. The electrophoresis systems utilize a high density array of microchannels for electrophoresis analysis with extended read lengths. The microchannel geometry can be used individually or in conjunction to increase the effective length of a separation channel while minimally impacting the packing density of channels. One embodiment uses sinusoidal microchannels, while another embodiment uses plural microchannels interconnected by a via. The extended channel systems can be applied to virtually any type of channel confined chromatography.

Davidson, James C. (Livermore, CA); Balch, Joseph W. (Livermore, CA)

2000-01-01

268

Simple differential detection of Entamoeba histolytica and Entamoeba dispar in fresh stool specimens by sodium acetate-acetic acid-formalin concentration and PCR.  

PubMed Central

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. PMID:9196177

Troll, H; Marti, H; Weiss, N

1997-01-01

269

Acetic acid mediated interactions between alumina surfaces  

NASA Astrophysics Data System (ADS)

Low-molecular-weight organic acids have been known to modify colloidal stability of alumina-based suspensions. We investigated interaction forces between alumina surfaces mediated by acetic acid which is one of the simplest organic acids. Forces between alumina surfaces were measured using the colloid-probe method of atomic force microscope (AFM). Repulsive forces attributed to steric repulsion due to adsorbed molecules and electrostatic repulsion dominated the interaction. Results of rheological characterization of the alumina slurry containing acetic acid supported the finding.

Sato, Kimiyasu; Y?lmaz, Hüseyin; Ijuin, Atsuko; Hotta, Yuji; Watari, Koji

2012-02-01

270

Free zone electrophoresis simulation of static column electrophoresis in microgravity on shuttle flight STS-3  

NASA Technical Reports Server (NTRS)

Experiments were designed to replicate, as closely as possible in 1-G, the conditions of the STS-3 red blood cell (RBC) experiments. Free zone electrophoresis was the method of choice, since it minimizes the role of gravity in cell migration. The physical conditions of the STS-3 experiments were used, and human and rabbit RBC's fixed by the same method were the test particles. The effects of cell concentration, electroosmotic mobility, and sample composition were tested in order to seek explanations for the STS-3 results and to provide data on cell concentration effects for future zero-G separation on the continuous-flow zero-G electrophoretics separator.

Todd, P. W.; Hjerten, S.

1985-01-01

271

Amphiphilic Membranes  

E-print Network

Contents: 1. Introduction 2. Amphiphilic molecules and the phases they form 3. Isolated membranes: the Helfrich hamiltonian 4. Vesicle shapes 5. Shape fluctuations in vesicles 6. Interacting fluid membranes 7. Conclusions A. Differential equations for vesicle shapes B. The Faddeev-Popov determinant C. One-loop calculation of the renormalization group D. The Liouville model

Luca Peliti

1995-01-17

272

Electromembrane extraction of amino acids from body fluids followed by capillary electrophoresis with capacitively coupled contactless conductivity detection  

Microsoft Academic Search

Electromembrane extraction (EME) proved to be a simple and rapid pretreatment method for analysis of amino acids and related compounds in body fluid samples. Body fluids were acidified to the final concentration of 2.5M acetic acid and served as donor solutions. Amino acids, present as cations in the donor solutions, migrated through a supported liquid membrane (SLM) composed of 1-ethyl-2-nitrobenzene\\/bis-(2-ethylhexyl)phosphonic

Lenka Strieglerová; Pavel Kubá?; Petr Bo?ek

2011-01-01

273

Analysis of protoberberine alkaloids in several herbal drugs and related medicinal preparations by non-aqueous capillary electrophoresis.  

PubMed

A simple, rapid, reproducible, and universal non-aqueous capillary electrophoresis method has been developed for the separation and determination of three major active protoberberine alkaloids including berberine, palmatine, and jatrorrhizine within 7 min. The effects of the concentrations of acetic acid and electrolyte, the ratio of organic solvent, and the applied voltage on the separation were investigated. The optimum running buffer was composed of 50 mM ammonium acetate, 0.5% (v/v) acetic acid, and 10% (v/v) acetonitrile in methanol. The applied voltage was 18 kV. The analytes were detected by UV at 214 nm. The linearities between peak areas and the concentrations of the analytes were also investigated, and they exhibit excellent linear behavior over the concentration ranges (correlation coefficients: 0.9975-0.9986). The method was successfully applied to determine the three alkaloids in several families of herbal drugs (Rhizoma Coptidis, Cortex Berberidis, Cortex Phellodendri, Herba Chelidonii, Caulis Mahoniae) and their relevant medicinal preparations for the first time, and the recoveries of the three constituents ranged between 95.6-103.2% for berberine, 97.5-103.3% for palmatine, and 96.1 -103.6% for jatrorrhizine. PMID:15688637

Wen, Hua Gao; Lin, Shao Yu; Jia, Li; Guo, Xi Kun; Chen, Xing Guo; Hu, Zhi De

2005-01-01

274

A novel approach to pseudopodia proteomics: excimer laser etching, two-dimensional difference gel electrophoresis, and confocal imaging  

PubMed Central

Pseudopodia are actin-rich ventral cellular protrusions shown to facilitate the migration and metastasis of tumor cells. Here, we present a novel approach to perform pseudopodia proteomics. Tumor cells growing on porous membranes extend pseudopodia into the membrane pores. In our method, cell bodies are removed by horizontal ablation at the basal cell surface with the excimer laser while pseudopodia are left in the membrane pores. For protein expression profiling, whole cell and pseudopodia proteins are extracted with a lysis buffer, labeled with highly sensitive fluorescent dyes, and separated by two-dimensional gel electrophoresis. Proteins with unique expression patterns in pseudopodia are identified by mass spectrometry. The effects of the identified proteins on pseudopodia formation are evaluated by measuring the pseudopodia length in cancer cells with genetically modified expression of target proteins using confocal imaging. This protocol allows global identification of pseudopodia proteins and evaluation of their functional significance in pseudopodia formation within one month.

Mimae, Takahiro; Ito, Akihiko; Hagiyama, Man; Nakanishi, Jun; Hosokawa, Yoichiroh; Okada, Morihito; Murakami, Yoshinori; Kondo, Tadashi

2014-01-01

275

Phosphorylation of membrane proteins in erythrocytes treated with lead.  

PubMed Central

In immature rat microvessels, endothelial cells and glioma cells, exposure to lead results in an increase in the level of protein kinase C in membranes. In this paper we have extended these studies to human erythrocytes and, in addition, studied the phosphorylation of membrane proteins. A significant increase in the phosphorylation of membrane cytoskeletal proteins of molecular mass 120, 80, 52 and 45 kDa was observed in human erythrocytes treated for 60 min with lead acetate at concentrations greater than 100 nM. These same proteins were phosphorylated when erythrocytes were treated for 10 min with 50 nM phorbol 12-myristate 13-acetate (PMA). Similarly, protein kinase C activity was elevated and an increase in the amount of protein kinase C-alpha was observed in membranes from erythrocytes exposed to concentrations of lead acetate above 100 nM. No changes, however, in the activities of cAMP-dependent protein kinase, protein phosphatases I and IIA or casein kinase were observed. Phosphorylation of these membrane proteins stimulated by lead acetate or by PMA was not observed in erythrocytes depleted of protein kinase C by a 72-h treatment with 500 nM phorbol 12,13-dibutyrate. Finally, no changes in the levels of calcium or diacylglycerol were observed in erythrocytes stimulated with 100 nM lead acetate. These results indicate that, in erythrocytes, lead acetate stimulates the phosphorylation of membrane cytoskeletal proteins by a mechanism dependent on protein kinase C. Since levels of calcium or diacylglycerols did not increase, it appears that lead may activate the enzyme by a direct interaction. PMID:8615806

Belloni-Olivi, L; Annadata, M; Goldstein, G W; Bressler, J P

1996-01-01

276

Single molecule analysis of DNA electrophoresis in microdevices  

E-print Network

Given that current electrophoresis technology is inadequate for mapping large O[100 kilobasepair] DNA, several promising lab-on-chip designs for DNA mapping have been recently proposed that require either 1) a DNA molecule ...

Randall, Greg C

2006-01-01

277

Dna electrophoresis in photopolymerized polyacrylamide gels on a microfluidic device  

E-print Network

DNA gel electrophoresis is a critical analytical step in a wide spectrum of genomic analysis assays. Great efforts have been directed to the development of miniaturized microfluidic systems (“lab-on-a-chip” systems) to perform low-cost, high...

Lo, Chih-Cheng

2009-05-15

278

A model for sample stacking in microcapillary DNA electrophoresis  

E-print Network

Sanger's method of chain termination is the method of choice in DNA sequencing, where electrophoresis is used to separate the different sized DNA. In the past decade, microfabricated capillary devices have been developed ...

Srivastava, Alok Kumar, 1967-

2002-01-01

279

Electrophoresis 2012, 33, 10791085 1079 Kevin H. Patel  

E-print Network

.1002/elps.201100417 1 Introduction The principle of Joule heating, heat dissipation, and varia- tion to consider Joule heating in electromigration techniques as it stimulates temperature changes electrical heating is an inherent limitation of capillary electrophoresis (CE). Active cooling systems

Krylov, Sergey

280

Biological nitrogen and phosphorus removal and changes in microbial community structure in a membrane bioreactor: Effect of different carbon sources  

Microsoft Academic Search

Bacterial community structures in four sequencing anoxic\\/anaerobic–aerobic membrane bioreactors (SAMs) that were fed with synthetic medium composed of different organic compounds in substrate as carbon source; acetate-dominant (acetate\\/propionate=4\\/1), propionate-dominant (acetate\\/propionate=1\\/4), glucose-dominant (glucose\\/acetate=4\\/1) and methanol-dominant (methanol\\/acetate\\/propionate=6\\/3\\/1) were analyzed by respiratory quinone profile and fluorescent in situ hybridization (FISH) techniques. The SAMs were operated at controlled pH range 7–8.5 and at constant

Zubair Ahmed; Byung-Ran Lim; Jinwoo Cho; Kyung-Guen Song; Ki-Pal Kim; Kyu-Hong Ahn

2008-01-01

281

Monitoring Insulin Aggregation via Capillary Electrophoresis  

PubMed Central

Early stages of insulin aggregation, which involve the transient formation of oligomeric aggregates, are an important aspect in the progression of Type II diabetes and in the quality control of pharmaceutical insulin production. This study is the first to utilize capillary electrophoresis (CE) with ultraviolet (UV) detection to monitor insulin oligomer formation at pH 8.0 and physiological ionic strength. The lag time to formation of the first detected species in the aggregation process was evaluated by UV-CE and thioflavin T (ThT) binding for salt concentrations from 100 mM to 250 mM. UV-CE had a significantly shorter (5–8 h) lag time than ThT binding (15–19 h). In addition, the lag time to detection of the first aggregated species via UV-CE was unaffected by salt concentration, while a trend toward an increased lag time with increased salt concentration was observed with ThT binding. This result indicates that solution ionic strength impacts early stages of aggregation and ?-sheet aggregate formation differently. To observe whether CE may be applied for the analysis of biological samples containing low insulin concentrations, the limit of detection using UV and laser induced fluorescence (LIF) detection modes was determined. The limit of detection using LIF-CE, 48.4 pM, was lower than the physiological insulin concentration, verifying the utility of this technique for monitoring biological samples. LIF-CE was subsequently used to analyze the time course for fluorescein isothiocyanate (FITC)-labeled insulin oligomer formation. This study is the first to report that the FITC label prevented incorporation of insulin into oligomers, cautioning against the use of this fluorescent label as a tag for following early stages of insulin aggregation. PMID:22272138

Pryor, Elizabeth; Kotarek, Joseph A.; Moss, Melissa A.; Hestekin, Christa N.

2011-01-01

282

Nonlinear electrophoresis of ideally polarizable particles  

NASA Astrophysics Data System (ADS)

We focus in this paper on the nonlinear electrophoresis of ideally polarizable particles. At high applied voltages, significant ionic exchange occurs between the electric double layer, which surrounds the particle, and the bulk solution. In addition, steric effects due to the finite size of ions drastically modify the electric potential distribution in the electric double layer. In this situation, the velocity field, the electric potential, and the ionic concentration in the immediate vicinity of the particle are described by a complicated set of coupled nonlinear partial differential equations. In the general case, these equations must be solved numerically. In this study, we rely on a numerical approach to determine the electric potential, the ionic concentration, and the velocity field in the bulk solution surrounding the particle. The numerical simulations rely on a pseudo-spectral method which was used successfully by Chu and Bazant [J. Colloid Interface Sci. 315(1), 319-329 (2007)] to determine the electric potential and the ionic concentration around an ideally polarizable metallic sphere. Our numerical simulations also incorporate the steric model developed by Kilic et al. [Phys. Rev. E 75, 021502 (2007)] to account for crowding effects in the electric double layer, advective transport, and for the presence of a body force in the bulk electrolyte. The simulations demonstrate that surface conduction significantly decreases the electrophoretic mobility of polarizable particles at high zeta potential and at high applied electric field. Advective transport in the electric double layer and in the bulk solution is also shown to significantly impact surface conduction.

Figliuzzi, B.; Chan, W. H. R.; Moran, J. L.; Buie, C. R.

2014-10-01

283

Nicked-sleeve interface for two-dimensional capillary electrophoresis  

PubMed Central

We report an improved interface for two-dimensional capillary electrophoresis. This interface is based on capillary tubing and a Plexiglas chip, both of which were milled using a micro-dicing saw. The interface was evaluated and compared to a traditional interface design for both pseudo one-dimensional and two-dimensional capillary electrophoresis. We observe less than 70% transfer efficiency for the traditional design and greater than 90% transfer efficiency with this new interface. PMID:23702824

Flaherty, Ryan J.; Huge, Bonnie J.; Bruce, Spencer M.; Dada, Oluwatosin O.; Dovichi, Norman J.

2013-01-01

284

Determination of acid dissociation constants by capillary electrophoresis  

Microsoft Academic Search

Capillary electrophoresis affords a simple, automated approach for the measurement of pKa values in the range 2–11 at a throughput of less than 1h per sample per instrument. Agreement with literature values is usually within 0.20 log units with a precision better than 0.07 log units. The attractive features of capillary electrophoresis for pKa measurements are: (1) conventional instrumentation with

Salwa K Poole; Sneha Patel; Karen Dehring; Heather Workman; Colin F Poole

2004-01-01

285

Microchip-based capillary electrophoresis of human serum proteins  

Microsoft Academic Search

The separation and relative quantitation of human serum proteins is important to the clinical diagnosis of various states of disease. Microchip-based capillary electrophoresis (CE) of human serum proteins offers several advantages over sodium dodecyl sulfate-poly(acrylamide) gel electrophoresis and conventional CE methods, including decreased sample consumption and analysis time and the possibility of on-chip sample manipulation (dilution, labelling, etc.). The microchip

Christa L. Colyer; Shakuntala D. Mangru; D. Jed Harrison

1997-01-01

286

Immunotoxicity of Trenbolone Acetate in Japanese Quail  

Microsoft Academic Search

Trenbolone acetate is a synthetic androgen that is currently used as a growth promoter in many meat-exporting countries. Despite industry laboratories classifying trenbolone as nonteratogenic, data showed that embryonic exposure to this androgenic chemical altered development of the immune system in Japanese quail. Trenbolone is lipophilic, persistent, and released into the environment in manure used as soil fertilizer. This is

Michael James Quinn; Moira McKernan; Emma T. Lavoie; Mary Ann Ottinger

2006-01-01

287

21 CFR 73.2396 - Lead acetate.  

Code of Federal Regulations, 2013 CFR

21 Food and Drugs 1 2013-04-01 2013-04-01...acetate. 73.2396 Section 73.2396 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT...than 4.7 and not more than 5.8. Arsenic (as As), not more than 3 parts...

2013-04-01

288

Heat Bonding of Irradiated Ethylene Vinyl Acetate  

NASA Technical Reports Server (NTRS)

Reliable method now available for joining parts of this difficult-tobond material. Heating fixture encircles ethylene vinyl acetate multiplesocket part, providing heat to it and to tubes inserted in it. Fixtures specially designed to match parts to be bonded. Tube-and-socket bonds made with this technique subjected to tensile tests. Bond strengths of 50 percent that of base material obtained consistently.

Slack, D. H.

1986-01-01

289

Process for the preparation of vinyl acetate  

DOEpatents

This invention pertains to the preparation of vinyl acetate by contacting within a contact zone a mixture of ketene and acetaldehyde with an acid catalyst at about one bar pressure and between about 85 and 200 C and removing the reaction products from the contact zone.

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

1998-02-17

290

Strengths of the Chloro-acetic Acids  

Microsoft Academic Search

IT is well known that the introduction of chlorine atoms into acetic acid causes a rapid rise of dissociation constant (see ). If changes in the value of K are taken as a measure of the effect of the chlorine atoms, it would appear that the second chlorine atom has a greater effect than the first, and the third a

John Shorter; F. J. Stubbs

1949-01-01

291

Process for the preparation of vinyl acetate  

DOEpatents

This invention pertains to the preparation of vinyl acetate by contacting within a contact zone a mixture of ketene and acetaldehyde with an acid catalyst at about one bar pressure and between about 85.degree. and 200.degree. C. and removing the reaction products from the contact zone.

Tustin, Gerald Charles (Kingsport, TN); Zoeller, Joseph Robert (Kingsport, TN); Depew, Leslie Sharon (Kingsport, TN)

1998-01-01

292

Corrosion of stainless steel during acetate production  

SciTech Connect

Corrosion of types 304, 304L, 316, and 316L stainless steel (SS) during the esterification of acetic acid and alcohol or glycol ether was investigated. The catalyst for this reaction, sulfuric acid or para-toluene sulfonic acid (PTSA), was shown to cause more corrosion on reactor equipment than CH{sub 3}COOH under the process conditions commonly practiced in industry. The corrosive action of the catalyst occurred only in the presence of water. Thus, for the batch processes, corrosion occurred mostly during the initial stage of esterification, where water produced by the reaction created an aqueous environment. After water was distilled off, the corrosion rate declined to a negligible value. The corrosion inhibitor copper sulfate, often used in industrial acetate processes, was found to work well for a low-temperature process (< 95 C) such as in production of butyl acetate, but it accelerated corrosion in the glycol ether acetate processes where temperatures were > 108 C. Process conditions that imparted low corrosion rates were determined.

Qi, J.S.; Lester, G.C. [Occidental Chemical Corp. Technology Center, Grand Island, NY (United States)

1996-07-01

293

Fermentative biohydrogen production from lactate and acetate.  

PubMed

In this study, a continuous-flow stirred tank reactor (CSTR) fed with lactate and acetate was operated to enrich hydrogen-producing bacteria. By varying the influent substrate concentrations and hydraulic retention times (HRT), the volumetric loading rate (VLR) of 55.64 kg-COD/m(3)/day seemed to be optimum for this enriched culture for fermentative hydrogen production from lactate and acetate. The results of batch experiments confirmed that the enriched culture tended to fulfill the e(-) equiv requirement for cell growth at a lower VLR condition (21.77 kg-COD/m(3)/day), while it could largely distribute the e(-) equiv for hydrogen production at a higher VLR condition. However, a maximum lactate/acetate concentration allowed for enriching this culture existed, especially at a lower HRT condition in which wash-out can be an issue for this enriched culture. Finally, the results of cloning and sequencing indicated that Clostridium tyrobutyricum was considered the major hydrogen-producing bacteria in the CSTR fed with lactate and acetate. PMID:22318084

Wu, Chao-Wei; Whang, Liang-Ming; Cheng, Hai-Hsuan; Chan, Kan-Chi

2012-06-01

294

Chiral separation of amines with N-benzoxycarbonylglycyl- L-proline as selector in non-aqueous capillary electrophoresis using methanol and 1,2-dichloroethane in the background electrolyte  

Microsoft Academic Search

N-Benzoxycarbonylglycyl-L-proline (L-ZGP) has been introduced as a chiral selector for enantioseparation of amines in non-aqueous capillary electrophoresis. Methanol mixed with different proportions of dichloromethane, 1,2-dichloroethane or 2-propanol containing L-ZGP and ammonium acetate was used as the background electrolyte. Enantioseparation of different types of pharmacologically active amines was performed, e.g. the local anaesthetic bupivacaine and the ?-adrenoceptor blocking agent pindolol. Addition

Ylva Hedeland; Mikael Hedeland; Ulf Bondesson; Curt Pettersson

2003-01-01

295

Crystalline Membranes  

NASA Technical Reports Server (NTRS)

In certain aspects, the invention features methods for forming crystalline membranes (e.g., a membrane of a framework material, such as a zeolite) by inducing secondary growth in a layer of oriented seed crystals. The rate of growth of the seed crystals in the plane of the substrate is controlled to be comparable to the rate of growth out of the plane. As a result, a crystalline membrane can form a substantially continuous layer including grains of uniform crystallographic orientation that extend through the depth of the layer.

Tsapatsis, Michael (Inventor); Lai, Zhiping (Inventor)

2008-01-01

296

Polyethylene-supported polyvinylidene fluoride-cellulose acetate butyrate blended polymer electrolyte for lithium ion battery  

NASA Astrophysics Data System (ADS)

The polyethylene (PE)-supported polymer membranes based on the blended polyvinylidene fluoride (PVDF) and cellulose acetate butyrate (CAB) are prepared for gel polymer electrolyte (GPE) of lithium ion battery. The performances of the prepared membranes and the resulting GPEs are investigated by scanning electron microscopy, electrochemical impedance spectroscopy, linear potential sweep, and charge-discharge test. The effect of the ratio of PVDF to CAB on the performance of the prepared membranes is considered. It is found that the GPE based on the blended polymer with PVDF:CAB = 2:1 (in weight) has the largest ionic conductivity (2.48 × 10-3 S cm-1) and shows good compatibility with anode and cathode of lithium ion battery. The LiCoO2/graphite battery using this GPE exhibits superior cyclic stability at room temperature, storage performance at elevated temperature, and rate performance.

Liu, Jiansheng; Li, Weishan; Zuo, Xiaoxi; Liu, Shengqi; Li, Zhao

2013-03-01

297

The microwave spectrum of n-hexyl acetate and structural aspects of n-alkyl acetates  

NASA Astrophysics Data System (ADS)

The microwave spectrum of n-hexyl acetate was recorded in the range of 10-13.5 GHz using the Aachen MB-FTMW spectrometer. The rotational constants of the most abundant conformer were determined to be A = 3.3591100(32) GHz, B = 0.39596553(53) GHz, and C = 0.36999804(31) GHz. Quantum chemical calculations for specific conformers were carried out at the MP2/6-311++G(d,p) level. The programs XIAM and BELGI were used to analyze the internal rotation of the acetyl methyl group. The observed conformer of n-hexyl acetate was compared to the lowest energy conformers of n-butyl acetate and n-pentyl acetate.

Attig, T.; Kannengießer, R.; Kleiner, I.; Stahl, W.

2014-04-01

298

Trypanosomatidae Produce Acetate via a Mitochondrial Acetate:Succinate CoA Transferase  

Microsoft Academic Search

Hydrogenosome-containing anaerobic protists, such as the trichomonads, produce large amounts of acetate by an acetate:succinate CoA transferase (ASCT)\\/succinyl CoA synthetase cycle. The notion that mitochondria and hydrogenosomes may have originated from the same alpha -proteobacterial endosymbiont has led us to look for the presence of a similar metabolic pathway in trypanosomatids because these are the earliest-branching mitochondriate eukaryotes and because

Jaap J. van Hellemond; Fred R. Opperdoes; Aloysius G. M. Tielens

1998-01-01

299

Solid–liquid equilibrium in the acetic acid–acetophenone and acetic acid–formamide systems  

Microsoft Academic Search

Solid–liquid equilibrium in the binary systems acetic acid–acetophenone and acetic acid–formamide was determined from time–temperature cooling and warming curves. The first system shows a sagged curve with a eutectic point at x1?0.6 and T=267.18 K. In the second system a solid compound (2:1) was found and an equilibrium constant of the compound dissociation was calculated.

I. Malijevská; Z. Sedláková

2006-01-01

300

Characterization of copolymer latexes by capillary electrophoresis.  

PubMed

Latexes are widely used for industrial applications, including decorative paints, binders for the papermaking industry, and drilling fluids for oil-field applications. In this work, the interest of capillary zone electrophoresis (CE) for the characterization of hydrophobic block copolymer latexes obtained by the conventional emulsion polymerization technique consisting of a core of polystyrene (PS) surrounded by a layer of poly(ethyl acrylate) (PEA) has been investigated. The PEA part of the copolymer can be partially hydrolyzed in poly(acrylic acid) (PAA) leading to PS-PEA-AA water-soluble amphiphilic copolymer having high viscosifying properties. The main purpose of this work was to evaluate the potential of CE for the characterization of the latexes at the different stages of the synthesis (PS core, PS-PEA diblock latex, and hydrolyzed PS-PEA-AA gel). The main analytical issues were to state (i) if there was free PS or PEA homopolymer latexes in the PS-PEA latex sample and (ii) if there was free PS, PEA, PS-PEA latexes, or free PAA chains in the PS-PEA-AA gel. Within this scope, this work describes the optimization of the selectivity of the separation between the different species (PS, PEA particles in the not hydrolyzed diblock latex and PS, PEA, PS-PEA particles as well as the polymer PAA chains in the PS-PEA-AA diblock gel sample obtained by latter latex hydrolysis). For that purpose, several experimental parameters were investigated such as pH and ionic strength of the background electrolyte (BGE) or the concentration of neutral surfactant added in the BGE. A challenging issue was to overcome the high viscosity of the PS-PEA-AA gel. This was resolved by the addition of 10 mM neutral surfactant in the gel sample and in the BGE. Finally, it is demonstrated that, within the detection limits, CE is a suitable analytical tool for controlling and monitoring the syntheses of these latexes and for intrinsically characterizing the distribution in charge density of the final PS-PEA-AA gel at different hydrolysis rates. PMID:19873976

Anik, Nadia; Airiau, Marc; Labeau, Marie-Pierre; Bzducha, Wojciech; Cottet, Hervé

2010-02-01

301

Charged Membranes  

NSDL National Science Digital Library

This Teaching Resource provides three animated lessons that describe the storage and utilization of energy across plasma membranes. The “Na,K ATPase” animation explains how these pumps establish the electrochemical gradient that stores energy across plasma membranes. The “ATP synthesizing complexes” animation shows how these complexes transfer energy from the inner mitochondrial membrane to adenosine triphosphate (ATP). The “action potential” lesson explains how charged membranes are used to propagate signals along the axons of neurons. These animations serve as valuable resources for any collegiate-level course that describes these important factors. Courses that might employ them include introductory biology, biochemistry, biophysics, cell biology, pharmacology, and physiology.

Jack D. Thatcher (Lewisburg;West Virginia School of Osteopathic Medicine REV)

2013-04-16

302

Use of pulsed-field gel electrophoresis to measure DNA damage and repair  

SciTech Connect

A method is described here for the analysis of single-strand break formation and repair in genomic DNA. The procedure involves exposing cells to a DNA-damaging agent, allowing time for recovery, and embedding the cells in agarose. After lysis and digestion with a protease, the DNA, which remains in the agarose plug, is denatured with glyoxal and separated by pulsed-field gel electrophoresis. The DNA in the gel is then transferred to a support membrane and quantitated with a radioanalytic imaging system to determine the average size of the DNA at each time point of recovery. The results indicate that the repair of methyl-induced breaks in total genomic DNA is approximately 80% complete in 48 hr in CHO B11 and ARL 14 cells exposed to dimethyl sulfate. These results are in agreement with those obtained by using other techniques like alkaline sucrose sedimentation. The method developed and described here has several advantages over existing techniques for repair measurements: It can be used to monitor genotoxic agents that nick DNA, to study the removal of breaks from genomic DNA, and to test for repair of damage in specific domains of chromatin that would be too large to examine by conventional electrophoresis.

Scicchitano, D.A. (American Health Foundation, Valhalla, NY (United States) New York Univ., New York (United States))

1991-03-11

303

Membrane Proteins A membrane protein is a  

E-print Network

Membrane Proteins A membrane protein is a protein molecule that is attached to, or associated with the membrane of a cell or an organelle. More than half of all proteins interact with membranes. #12;Membrane Proteins - Func2on Biological membranes consist of a phospholipid bilayer and a variety of proteins

Cavanagh, John

304

Membrane Rafts  

NSDL National Science Digital Library

The main focus of this three part series is to explore the concept of "Membrane Rafts". In the first part, we will examine what is popularly understood by the term "Membrane Raft" and ask why this concept was proposed in the first place. With a focus on the study of the characteristics of a popular "raft-marker", a class of cell surface lipid-tethered proteins, the GPI-anchored proteins.

Satyajit 'Jitu' Mayor (Cellular Organisation and Signalling, National Centre for Biological Sciences, Bangalore, India;)

2007-05-01

305

Shotgun proteomics of plant plasma membrane and microdomain proteins using nano-LC-MS/MS.  

PubMed

Shotgun proteomics allows the comprehensive analysis of proteins extracted from plant cells, subcellular organelles, and membranes. Previously, two-dimensional gel electrophoresis-based proteomics was used for mass spectrometric analysis of plasma membrane proteins. In order to get comprehensive proteome profiles of the plasma membrane including highly hydrophobic proteins with a number of transmembrane domains, a mass spectrometry-based shotgun proteomics method using nano-LC-MS/MS for proteins from the plasma membrane proteins and plasma membrane microdomain fraction is described. The results obtained are easily applicable to label-free protein semiquantification. PMID:24136542

Takahashi, Daisuke; Li, Bin; Nakayama, Takato; Kawamura, Yukio; Uemura, Matsuo

2014-01-01

306

Method development and validation for the simultaneous determination of cinnarizine and co-formulated drugs in pharmaceutical preparations by capillary electrophoresis  

Microsoft Academic Search

Rapid and simple capillary electrophoresis (CE) methods were developed for the simultaneous determinations of cinnarizine and domperidone (CN\\/DOM) and cinnarizine and nicergoline (CN\\/NIC) in their co-formulated tablets. The optimized CE conditions were as follows: running buffer, methanol–acetate buffer (pH 3.0, 10mM) (80:20 and 85:15 (v\\/v) for CN\\/DOM and CN\\/NIC, respectively); applied voltage, 20kV; UV detection wavelengths, 215 and 227nm for

A. A. Abdelal; S. Kitagawa; H. Ohtani; N. El-Enany; F. Belal; M. I. Walash

2008-01-01

307

Electrophoresis of a polyelectrolyte through a nanopore  

NASA Astrophysics Data System (ADS)

A hydrodynamic model for determining the electrophoretic speed of a polyelectrolyte through a nanopore is presented. It is assumed that the speed is determined by a balance of electrical and viscous forces arising from within the pore and that classical continuum electrostatics and hydrodynamics may be considered applicable. An explicit formula for the translocation speed as a function of the pore geometry and other physical parameters is obtained and is shown to be consistent with experimental measurements on DNA translocation through nanopores in silicon membranes. Experiments also show a weak dependence of the translocation speed on polymer length that is not accounted for by the present model. It is hypothesized that this is due to secondary effects that are neglected here.

Ghosal, Sandip

2006-10-01

308

Electrophoresis of a polyelectrolyte through a nanopore.  

PubMed

A hydrodynamic model for determining the electrophoretic speed of a polyelectrolyte through a nanopore is presented. It is assumed that the speed is determined by a balance of electrical and viscous forces arising from within the pore and that classical continuum electrostatics and hydrodynamics may be considered applicable. An explicit formula for the translocation speed as a function of the pore geometry and other physical parameters is obtained and is shown to be consistent with experimental measurements on DNA translocation through nanopores in silicon membranes. Experiments also show a weak dependence of the translocation speed on polymer length that is not accounted for by the present model. It is hypothesized that this is due to secondary effects that are neglected here. PMID:17155090

Ghosal, Sandip

2006-10-01

309

Recent Developments in Instrumentation for Capillary Electrophoresis and Microchip-Capillary Electrophoresis  

PubMed Central

Over the last years there has been an explosion in the number of developments and applications of capillary electrophoresis (CE) and microchip-CE. In part, this growth has been the direct consequence of recent developments in instrumentation associated with CE. This review, which is focused on contributions published in the last five years, is intended to complement the papers presented in this special issue dedicated to Instrumentation and to provide an overview on the general trend and some of the most remarkable developments published in the areas of high voltage power supplies, detectors, auxiliary components, and compact systems. It also includes few examples of alternative uses of and modifications to traditional CE instruments. PMID:20665910

Felhofer, Jessica L.; Blanes, Lucas; Garcia, Carlos D.

2010-01-01

310

Biogas Production through the Syntrophic Acetate-Oxidising Pathway  

E-print Network

retention time OLR Organic loading rate PCR Polymerase chain reaction qPCR Quantitative polymerase chain reaction RNA Ribonucleic acid SAO Syntrophic acetate oxidation SAOB Syntrophic acetate-oxidising bacteria

311

Separating acetic acid from furol (furfural) by electrodialysis method  

SciTech Connect

Furfural production by hydrolysis of fibrous plant materials is accompanied by formation of acetic acid in amounts depending on the material used. The amount of acetic formed in the hydrolysis of the fruit shell of oil-tea camellia (Camellia oleosa) (an oilseed-bearing tree) is equal to the amount of furfural. The acetic acid can be separated from the furfural and concentrated to 10% by electrodialysis. A smaller amount of furfural is separated with acetic acid.

Guan, S.F.; Li, C.S. Ye, S.T.; Shen, S.Y.; Wang, Y.T.; Yu, S.H.

1981-01-01

312

l-Lysinium trifluoro-acetate.  

PubMed

Ions of the title compound, C(6)H(15)N(2)O(2) (+)·C(2)F(3)O(2) (-), a new organic nonlinear optical crystal, are linked by N-H?O hydrogen-bonding inter-actions. Both the amino groups of the l-lysinium cation are protonated. A three-dimensional network of hydrogen bonds is observed, forming a closed ring. Inter-molecular N-H?O hydrogen bonds involving l-lysinium cations and trifluoro-acetate anions link the ions into extended chains which run parallel to the [010] direction. The F atoms of the trifluoro-acetate anion are disordered over two sites with site occupancies of 0.423?(18) and 0.577?(18). The asymmetric unit consists of two cations and two anions. PMID:21201423

Sun, Zhi Hua; Fan, Jian Dong; Zhang, Guang Hui; Wang, Xin Qiang; Xu, Dong

2008-01-01

313

A capillary electrophoresis method for the characterization of ecto-nucleoside triphosphate diphosphohydrolases (NTPDases) and the analysis of inhibitors by in-capillary enzymatic microreaction  

Microsoft Academic Search

A capillary electrophoresis (CE) method for the characterization of recombinant NTPDases 1, 2, and 3, and for assaying NTPDase\\u000a inhibitors has been developed performing the enzymatic reaction within the capillary. After hydrodynamic injection of plugs\\u000a of substrate solution with or without inhibitor in reaction buffer, followed by a suspension of an enzyme-containing membrane\\u000a preparation, and subsequent injection of another plug

Jamshed Iqbal; Petra Vollmayer; Norbert Braun; Herbert Zimmermann; Christa E. Müller

2005-01-01

314

Functional Properties of Extruded Starch Acetate Blends  

Microsoft Academic Search

Starch acetate, with degree of substitution of 2, was blended with 0, 7.5 and 15% polylactic acid (PLA), Eastar Bio Copolyester 14766 (EBC) or Mater-Bi ZF03U (MBI) and 10%, 13%, or 16% (d.b.) ethanol and twin-screw extruded at 160°C barrel temperature. Physical characteristics of the extrudates, such as radial expansion ratio, unit and bulk densities, and of the mechanical properties,

J. Guan; Q. Fang; M. A. Hanna

2004-01-01

315

Corrosion of Stainless Steel During Acetate Production  

Microsoft Academic Search

Corrosion of types 304, 304L, 316, and 316L stainless steel (SS) during the esterification of acetic acid and alcohol or glycol ether was investigated. The catalyst for this reaction, sulfuric acid or para-toluene sulfonic acid (PTSA), was shown to cause more corrosion on reactor equipment than CHâCOOH under the process conditions commonly practiced in industry. The corrosive action of the

J. S. Qi; G. C. Lester

1996-01-01

316

Membrane process for separating H{sub 2}S from natural gas  

SciTech Connect

Objective was to develop a membrane process for separating hydrogen sulfide and other impurities (CO{sub 2}, water vapor) from low-quality natural gas. A membrane material was identified with very high H{sub 2}/CH{sub 4} selectivity in the range of 40--60; membrane production was scaled up to commercial size rolls; high-pressure membrane and module development and optimization were completed; and a membrane permeation flux of 4{times}10{sub {minus}6} cm{sup 3}/s{center_dot}cm{sup 2}cmHg, twice as high state-of-the-art cellulose acetate membranes, was achieved.

Baker, R.W.

1995-07-01

317

Electrophoresis of DNA and other polyelectrolytes: Physical mechanisms  

NASA Astrophysics Data System (ADS)

The dramatic recent advances in molecular biology, which have opened a new era in medicine and biotechnology, rely on improved techniques to study large molecules. Electrophoresis is one of the most important of these. Separation of DNA by size, in particular, is at the heart of genome mapping and sequencing and is likely to play an increasing role in diagnosis. This article reviews, from the point of view of a physicist, the mechanisms responsible for electrophoretic separation of polyelectrolytes. This separation is mainly performed in gels, and a wide variety of migration mechanisms can come into play, depending on the polyelectrolyte's architecture, on the electric fields applied, and on the properties of the gel. After a brief review of the thermodynamic and electrohydrodynamic principles relating to polyelectrolyte solutions, the author treats the phenomenology of electrophoresis and describes the conceptual and theoretical tools in the field. The reptation mechanisms, by which large flexible polyelectrolytes thread their way through the pores of the gel matrix, play a prominent role. Biased reptation, the extension of this model to electrophoresis, provides a very intuitive framework within which numerous physical ideas can be introduced and discussed. It has been the most popular theory in this domain, and it remains an inspiring concept for current development. There have also been important advances in experimental techniques such as single-molecule viodeomicroscopy and the development of nongel separation media and mechanisms. These, in turn, form the basis for fast-developing and innovative technologies like capillary electrophoresis, electrophoresis on microchips, and molecular ratchets.

Viovy, Jean-Louis

2000-07-01

318

Lithium acetate transformation of yeast Maitreya Dunham August 2004  

E-print Network

Lithium acetate transformation of yeast Maitreya Dunham August 2004 Original protocol from Katja until the OD600 is around 0.7-0.8 (~7 hours). Spin down the cells. Resuspend in 5 ml lithium acetate mix. Spin. Resuspend in 0.5 ml lithium acetate mix. Transfer to an eppendorf tube. Incubate 60 minutes

Dunham, Maitreya

319

Development of an Amperometric Acetic Acid Sensor in Organic System  

Microsoft Academic Search

An amperometric method was developed by using a lead working electrode in acetonitrile organic solution for detecting acetic acid. The mechanisms of electrochemical reaction were corresponding to the reduction of acetic ions in acetonitrile organic solution. The steady state amperometric current resulted from the reduction of acetic ions to produce the aldehyde in a two-electron process. In the organic sensing

Shin Lin; Tse-Chuan Chou

320

Effects of nitrobenzene and zinc on acetate utilizing methanogens  

Microsoft Academic Search

Determination of anaerobic degradation rates and toxic effects of nitrobenzene (NB) on acetate utilizing methanogens was the first objective of this research. Serum bottles were used for anaerobic toxicity assays with an acetate enrichment culture of methanogens. Ten mg\\/l of nitrobenzene did not inhibit total gas production in the acetate enrichment methanogenic culture. Twenty and thirty mg\\/l of nitrobenzene caused

Sanjoy K. Bhattacharya; Mingbo Qu; Richard L. Madura

1996-01-01

321

Thermochemical characteristics of cellulose acetates with different degrees of acetylation  

NASA Astrophysics Data System (ADS)

The standard enthalpies of combustion and formation of cellulose acetates with different degrees of acetylation are determined. It is established that there is a proportional dependence of these thermochemical characteristics vs. the degree of acetylation, weight fraction of bonded acetic acid, and molar mass of the repeating unit of cellulose acetates.

Larina, V. N.; Ur'yash, V. F.; Kushch, D. S.

2012-12-01

322

Microcoil NMR study of the interactions between doxepin, ?-cyclodextrin, and acetate during capillary isotachophoresis.  

PubMed

The capillary isotachophoresis (cITP) separation of the isomers of the tricyclic antidepressant doxepin using ?-cyclodextrin (?-CD) as a buffer additive is investigated by online microcoil NMR detection. Capillary electrophoresis (CE) is also used to determine the binding constant between the doxepin E and Z geometric isomers and ?-CD. Although the doxepin isomers could be easily baseline resolved by CE, their separation by cITP was more challenging due in part to the high concentration of doxepin after cITP-focusing. The use of online (1)H NMR detection allows observation of changes in doxepin dynamics due to formation of the ?-CD inclusion complex, changes in the fraction complexed and the intracapillary pH. It also provides novel experimental evidence that a weak complex between ?-CD and acetate contributes to its active transport from the leading electrolyte through the sample band to the trailing electrolyte in this cationic cITP separation. The results of these cITP-NMR experiments provide new mechanistic details about the interactions of the buffer counterion acetate with various components of the separation system and have important implications for other analyses based on formation of cyclodextrin inclusion complexes. PMID:22852806

Jones, Christopher J; Larive, Cynthia K

2012-08-21

323

Separation of inner and outer membranes of Rhodopseudomonas spheroides.  

PubMed

The separation of inner and outer membrane of Rhodopseudomonas spheroides has been achieved by means of sucrose density gradient (20%, 40%, 60%, w/w) centrifugation. The upper fraction of the gradient, with a specific density 1.181 (g/cm3), is high in cytochrome and succinate dehydrogenase activities, low in lipopolysaccharides and it is designated the inner membrane fraction. The bottom fraction of the gradient, with a specific density 1.240, is high in lipopolysaccharide and contains neither cytochrome nor succinate dehydrogenase activities. This fraction is the cell wall or outer membrane fraction. The intermediate band on the gradient is an unseparated fraction of inner and outer membrane fragments. This fraction has a specific denisty of 1.211 and represents less than 3% of total crude envelope. Thin sections of the vesicles of the inner membrane fraction and those of outer membrane provide morphological evidence for the identity of the individual membrane fractions. At least 22 protein bands are resolved by employing sodium dodecyl sulfate slab gel electrophoresis. Six bands are present only in the inner membrane and two bands are found exclusively in the outer membrane. Most of the remaining polypeptides are present in greater amounts in the inner membrane relative to the outer membrane fractions. PMID:1083979

Ding, D H; Kaplan, S

1976-01-01

324

Electrophoresis of a polyelectrolyte through a nanopore  

NASA Astrophysics Data System (ADS)

Translocation of polyelectrolytes (such as DNA) through natural and artificial nanopores can be detected with single molecule resolution by monitoring the resistivity of the pore (Nature Biotechnology (2001) 19, pp. 248). The technique could evolve into a technology for sequencing DNA at speeds that are orders of magnitude faster than what is currently possible. Here a hydrodynamic model to determine the electrophoretic speed of a polyelectrolyte through a nanopore is presented. It is assumed that the speed is determined by a balance of electrical and viscous forces arising from within the pore and that classical continuum electrostatics and hydrodynamics may be considered applicable. An explicit formula for the translocation speed as a function of the pore geometry and other physical parameters is obtained and is shown to be consistent with experimental measurements on DNA translocation through nanopores in silicon membranes. Secondary effects such as the hydrodynamic friction on the part of the polymer outside the nanopore must also be considered to explain the weak dependence of the translocation speed on the polymer length.

Ghosal, Sandip

2006-11-01

325

Joule heating effects on peak broadening in capillary zone electrophoresis  

NASA Astrophysics Data System (ADS)

Based on Taylor-Aris dispersion theory, a general analytical formula was derived for the theoretical plate height in capillary zone electrophoresis with the consideration of Joule heating effects. During the electrophoresis, the Joule heating causes a temperature rise and temperature gradients in the buffer solution. The temperature variations can affect the molecular diffusion, electroosmotic flow and electrophoretic flow via the temperature-dependent diffusion coefficient, dynamic viscosity and electrical conductivity. All these factors contribute to the peak broadening and are considered simultaneously in the present general model. The general formula derived in this paper is employed to discuss quantitatively the peak broadening in the presence of Joule heating effects. This formula can be easily extended to capillary zone electrophoresis with higher zeta potentials, if an approximate solution to Poisson-Boltzmann equation is employed.

Xuan, Xiangchun; Li, Dongqing

2004-08-01

326

A novel ceramic-supported polymer membrane for pervaporation of dilute volatile organic compounds  

Microsoft Academic Search

A novel asymmetric ceramic-supported polymer (CSP) pervaporation membrane was developed using free-radical graft polymerization of polyvinyl acetate (PVAc) onto a porous tubular silica substrate. The resulting membrane was characterized by pervaporation removal of trichloroethylene (TCE) and chloroform from dilute aqueous solutions. PVAc was chosen since it has a high affinity for TCE and chloroform and a low affinity for water,

Jeng-Dung Jou; Wayne Yoshida; Yoram Cohen

1999-01-01

327

Accumulation of organochlorine pesticides by semipermeable membrane devices using composite complex  

Microsoft Academic Search

Semipermeable membrane devices (SPMDs) were developed for passive in situ monitoring of organochlorine pesticides (OCPs) in aqueous solution in both laboratory and field (Pearl River Delta, China) studies. The device consisted of a thin film of neutral lipid triolein, enclosed in thin-walled tubing made of composite cellulose acetate membrane (CA) supported by linear low density polyethylene (LLDPE) (CAPE). Results from

Long B. Liao; Xian M. Xiao

2006-01-01

328

Measuring the zeta (electrokinetic) potential of reverse osmosis membranes by a streaming potential analyzer  

Microsoft Academic Search

SUMMARY The use of a novel streaming potential analyzer to measure the zeta potential of cellulose acetate and composite polyamide reverse osmosis membranes is reported. Zeta potentials of these membranes were measured at various solution chemistries. These include effects of salt (NaCl) concentration, solution pH, and the presence of dissolved humic substances. It is demonstrated that streaming potential is a

Menachem Elimelech; William H. Chen; John J. Waypa

1994-01-01

329

EVALUATION OF MEMBRANE PERFORMANCE AND FOULING BY PYROLYSIS-GC/MS  

EPA Science Inventory

Pyrolysis-GC/MS is used to evaluate the organic foulants found on two types of membranes for three natural waters. olyamide and cellulose acetate membranes are used. aters from Manatee Lake, Harsha Lake, and the Ohio River are used as feed waters. he pyrolysis fragments are class...

330

Definition of performance specifications for automated Analytical Electrophoresis Facility (AAEF)  

NASA Technical Reports Server (NTRS)

In order to provide specifications for the automated Analytical Electrophoresis Facility (AAEF) that would satisfy the broadest variety of demands of a future user community, a survey was carried out of all those people who were identified as having published papers on cell electrophoresis in the past four years. A computer search was conducted of the relevant literature from which a list of 87 investigators was derived and defined as the user community for purposes of the mailing. A questionnaire was developed covering the areas of performance which required definition which was subsequently circulated to the user community. Based on the response to this survey performance specifications were assembled.

Brooks, D. E.

1976-01-01

331

Gel Electrophoresis of Gold-DNA Nano-Conjugates  

SciTech Connect

Single stranded DNA of different lengths and different amounts was attached to colloidal phosphine stabilized Au nanoparticles. The resulting conjugates were investigated in detail by a gel electrophoresis study based on 1200 gels. We demonstrate how these experiments help to understand the binding of DNA to Au particles. In particular we compare specific attachment of DNA via gold-thiol bonds with nonspecific adsorption of DNA. The maximum number of DNA molecules that can be bound per particle was determined. We also compare several methods to used gel electrophoresis for investigating the effective diameter of DNA-Au conjugates, such as using a calibration curve of particles with known diameters and Ferguson plots.

Pellegrino, T.; Sperling, R.A.; Alivisatos, A.P.; Parak, W.J.

2006-01-10

332

Capillary electrophoresis separations on a planar chip with the column-coupling configuration of the separation channels  

PubMed

Some basic aspects of capillary electrophoresis (CE) separations on a poly(methyl methacrylate) chip provided with two separation channels in the column-coupling (CC) configuration and on-column conductivity detectors were studied. The CE methods employed in this study included isotachophoresis (ITP), capillary zone electrophoresis (CZE), and CZE with on-line ITP sample pretreatment (ITP-CZE). Hydrodynamic and electroosmotic flows of the solution in the separation compartment of the chip were suppressed, and electrophoresis was a dominant transport process in the separations performed by these methods. Very reproducible migration velocities of the separated constituents were typical under such transport conditions, and consequently, test analytes could be quantified by various ITP techniques with 1-2% RSD. The CC configuration of the separation channels provides means for an effective combination of an enhanced load capacity of the separation system with high detection sensitivities for the analytes in concentration-cascade ITP separations. In this way, for example, succinate, acetate, and benzoate could be separated also in instances when they were present in the loaded sample (1.2 microL) at 1 mmol/L concentrations while their limits of detection ranged from 8 to 12 micromol/L concentrations. A well-defined ITP concentration of the analyte(s) combined with an in-column sample cleanup (via an electrophoretically driven removal of the matrix constituents from the separation compartment) can be integrated into the separations performed on the CC chip. These sample pretreatment capabilities were investigated in ITP-CZE separations of model samples in which nitrite, phosphate, and fluoride (each at a 10 micromol/L concentration) accompanied matrix constituents (sulfate and chloride) at considerably higher concentrations. Here, both the concentration of the analytes and cleanup of the sample were included in the ITP separation in the first separation channel while the second separation channel served for the CZE separation of the ITP pretreated sample and the detection of the analytes. PMID:10952548

Kaniansky; Masar; Bielcikova; Ivanyi; Eisenbeiss; Stanislawski; Grass; Neyer; Johnck

2000-08-01

333

The rejection of specific organic compounds by reverse osmosis membranes  

Microsoft Academic Search

The performance characteristics of two commercially available reverse osmosis (RO) membranes, one cellulose acetate and the other composite polyamide, were investigated with respect to the rejection of different organic compounds, in order to elucidate rejection mechanisms and to investigate correlation with certain solute physical-chemical parameters. Flux and rejection studies were conducted on a series of six alkyl phenols and a

C. Frederik Schutte

2003-01-01

334

Quality control of histamine and methacholine in diagnostic solutions with capillary electrophoresis.  

PubMed

Solutions of histamine and methacholine bromide in different matrices for diagnostic purposes were analyzed for stability and quality control using capillary electrophoresis. Histamine (2,[4-imidazolyl]ethylamine) [CAS No. 51-45-6] was determined using a 0.1 M Tris-borate buffer of pH 8.3 with 5.10(-5) M cetyltrimethylammonium bromide (CTAB) and 0.005% poly(vinyl alcohol) (PVA) and detected at 214 nm using clenbuterol [4-amino-alpha-(tert.-butylaminomethyl)-3,5-dichlorobenzyl alcohol] [37148-27-9] as an internal standard. Metacholine bromide (acetyl-beta-methacholine bromide) [333-31-3] was determined with a 0.01 M creatinine-chloride buffer of pH 4.85 and detected with indirect UV at 230 nm using potassium as an internal standard. Histamine solutions were stable for a prolonged period of time, whereas under enforced degradation conditions methacholine was hydrolyzed, yielding acetic acid and (tentatively) beta-methylcholine as reaction products. PMID:8777460

van der Schans, M J; Reijenga, J C; Everaerts, F M

1996-05-31

335

Non-aqueous capillary electrophoresis separation of fullerenes and C60 fullerene derivatives.  

PubMed

As the interest in the use of fullerene compounds in biomedical and cosmetic applications increases, so too does the need to develop methods for their determination and quantitation in such complex matrices. In this work, we studied the behavior of C60 and C70 fullerenes in non-aqueous capillary electrophoresis, as well as two C60 fullerene derivatives not previously reported by any electrophoretic method, N-methyl-fulleropyrrolidine and (1,2-methanofullerene C60)-61-carboxylic acid. The separation was performed using fused-silica capillaries with an I.D. of 50 ?m and tetraalkylammonium salts, namely tetra-n-decylammonium bromide (200 mM) and tetraethylammonium bromide (40 mM), in a solvent mixture containing 6 % methanol and 10 % acetic acid in acetonitrile/chlorobenzene (1:1?v/v) as the background electrolyte. Detection limits, based on a signal-to-noise ratio of 3:1, were calculated, and values between 1 and 3.7 mg/L were obtained. Good run-to-run and day-to-day precisions on concentration were achieved with relative standard deviation lower than 15 %. For the first time, an electrophoretic technique has been applied for the analysis of C60 fullerene in a commercial cosmetic cream. A standard addition method was used for quantitation, and the result was compared with that obtained by analyzing the same cream by liquid chromatography coupled to mass spectrometry. PMID:22526671

Astefanei, Alina; Núñez, Oscar; Galceran, M Teresa

2012-08-01

336

Capillary electrophoresis determinative and LC-MS confirmatory method for screening selected imidazolinone herbicides from soil.  

PubMed

Residues of imazapyr, imazamox, imazapic, imazethapyr, imazaquin, and imazamethabenz (meta and para) are extracted from soil with 0.5 N sodium hydroxide. The pH is adjusted to 2.0-2.2, and the resulting precipitate is filtered. Compounds are trapped onto a tC18 solid-phase extraction (SPE) cartridge, then eluted from the cartridge and passed through a strong anion exchange (SAX) SPE cartridge onto a benzenesulfonic acid strong cation exchange (SCX) cartridge using ethyl acetate. After eluting the analytes from the SCX cartridge using saturated potassium chloride in methanol, the solution is evaporated and redissolved in 1% formic acid in water. The sample is then desalted using a tC18 SPE cartridge and eluted with methanol. After evaporating the methanol to dryness, the compounds are partitioned from acidic solution (pH 3.5) into methylene chloride. The methylene chloride is evaporated to dryness and the residues are then dissolved in Milli-Q water (Millipore, Bedford, MA, U.S.A.) in preparation for analysis by capillary electrophoresis. Results are calculated by direct comparison of the sample peak heights to the peak heights of bracketing standards. The validated sensitivity of the method (LOQ, limit of quantitation) is 2.0 ppb for each compound. Confirmation for individual residues greater than 2.0 ppb is provided by liquid chromatography-electrospray ionization mass spectrometry (LC-ESMS) of the final extract. PMID:10327374

Nejad, H; Safarpour, M M; Cavalier, T; Picard, G; Souza, M; Krynitsky, A J; Chiu, S; Miller, P; Stout, S J

1998-01-01

337

Process control and drug analysis with an on-line capillary electrophoresis system.  

PubMed

Inorganic and organic ions in pulp and paper process waters and drug mixtures were studied. Real-time measurements and on-line simulated analyses were made. A novel on-line capillary electrophoresis instrument equipped with a fixed wavelength UV detector having a 254-nm filter was used for the analyses. Three dynamic sample and electrolyte micromodules provided on-line sampling, sample introduction and solution feedings. The system was used to monitor process samples containing thiosulphate, chloride, sulphate, oxalate, acetate and carbonate. It approved good performance in separation of ethacrynic acid, furosemide, probenecid, bumetanide and hydrochlorothiazide as well as that of normethanephrine, methanephrine and dopamine standard mixtures. The LOD and LOQ values of the ions and drugs ranged from 0.1 to 1 mg/l for LOD and from 1 to 10 mg/l for LOQ. Sensitivity of the drugs was higher due to the single wavelength available in the system. It required that the drugs were to be identified by indirect UV detection. Repeatability of the analyses was good (RSD% below 5). PMID:15345297

Sirén, Heli; Luomanperä, Kaija; Työppönen, Teemu; Rovio, Stella; Vastamäki, Pertti; Savolahti, Pekka

2004-09-30

338

Quantitative analysis of six pesticides in fruits by capillary electrophoresis-electrospray-mass spectrometry.  

PubMed

A method to identify and quantify six pesticide residues - dinoseb, pirimicarb, procymidone, pyrifenox, pyrimethanil, and thiabendazole - in peaches and nectarines using capillary electrophoresis-electrospray ionization-quadrupole ion trap-tandem mass spectrometry (CE-ESI-MS/MS) is described. Separation was carried out using a buffer of 0.3 M ammonium acetate at pH 4 with 10% methanol. Pesticide residues present in peach and nectarine samples were preconcentrated by solid-phase extraction using C(18), eluted with CH(2)Cl(2), concentrated to dryness, and redissolved in buffer to obtain lower detection limits. The recoveries of the analytes ranged from 58 to 99% and the relative standard deviations were 9 to 19%. Under optimized CE-MS/MS conditions the minimum detectable levels for the six pesticides in spiked peach samples were between 0.01 mg/kg for pirimicarb and 0.05 mg/kg for procymidone with pressure injection of 50 mbar for 5 s (5 nL) at a signal-to-noise ratio of 3, which constitutes a severalfold increase in sensitivity compared to CE-MS, using a single quadrupole, and to conventional CE-UV. The potential of the method was demonstrated by analyzing different samples taken from regional agricultural cooperatives. The pesticides most often detected were thiabendazole and procymidone. PMID:15759305

Juan-García, Ana; Font, Guillermina; Picó, Yolanda

2005-04-01

339

Chiral recognition of dapoxetine enantiomers with methylated-gamma-cyclodextrin: a validated capillary electrophoresis method.  

PubMed

The enantiomers of dapoxetine, a serotonin transporter inhibitor for the treatment of premature ejaculation have been separated by cyclodextrin modified capillary zone electrophoresis using uncoated fused-silica capillary. Over 20 cyclodextrins were screened as chiral selectors, investigating the stability of the inclusion complexes and enantioseparating properties. According to the preliminary experiments as chiral selector randomly methylated-?-cyclodextrin was chosen. The basic chemical and instrumental parameters of enantioseparation as concentration of buffer, chiral selector and organic additive, pH, temperature and applied voltage were optimized afterwards using an orthogonal experimental design. Using this methodology not only the optimal parameter values for chiral separation (15 °C, +15 kV, 70 mM acetate, 20 v/v% MeOH, pH*=4.5, 3 mM methylated-?-CyD) but also the significance order of factors on resolution was determined. Applying these parameters an optimal resolution of 7.01 was achieved. The optimized method was then validated according to the ICH guideline Q2 (R1) with regard to repeatability, linearity range, LOD, LOQ, accuracy and robustness. PMID:22280959

Neumajer, Gábor; Sohajda, Tamás; Darcsi, András; Tóth, Gerg?; Szente, Lajos; Noszál, Béla; Béni, Szabolcs

2012-03-25

340

Exploring chip-capillary electrophoresis-laser-induced fluorescence field-deployable platform flexibility: separations of fluorescent dyes by chip-based non-aqueous capillary electrophoresis.  

PubMed

Microfluidic chip electrophoresis (chip-CE) is a separation method that is compatible with portable and on-site analysis, however, only few commercial chip-CE systems with laser-induced fluorescence (LIF) and light emitting diode (LED) fluorescence detection are available. They are established for several application tailored methods limited to specific biopolymers (DNA, RNA and proteins), and correspondingly the range of their applications has been limited. In this work we address the lack of commercially available research-type flexible chip-CE platforms by exploring the limits of using an application-tailored system equipped with chips and methods designed for DNA separations as a generic chip-CE platform - this is a very significant issue that has not been widely studied. In the investigated Agilent Bioanalyzer chip-CE system, the fixed components are the Agilent chips and the detection (LIF at 635 nm and LEDIF at 470 nm), while the chemistry (electrolyte) and the programming of all the high voltages are flexible. Using standard DNA chips, we show that a generic CE function of the system is easily possible and we demonstrate an extension of the applicability to non-aqueous CE (NACE). We studied the chip compatibility with organic solvents (i.e. MeOH, ACN, DMF and DMSO) and demonstrated the chip compatibility with DMSO as a non-volatile and non-hazardous solvent with satisfactory stability of migration times over 50h. The generic CE capability is illustrated with separations of fluorescent basic blue dyes methylene blue (MB), toluidine blue (TB), nile blue (NB) and brilliant cresyl blue (BC). Further, the effects of the composition of the background electrolyte (BGE) on the separation were studied, including the contents of water (0-30%) and buffer composition. In background electrolytes containing typically 80 mmol/L ammonium acetate and 870 mmol/L acetic acid in 100% DMSO baseline separation of the dyes were achieved in 40s. Linearity was documented in the range of 5-28 ?mol/L, 10-100 ?mol/L, 1.56-50 nmol/L and 5-75 nmol/L (r(2) values in the range 0.974-0.999), and limit of detection (LOD) values were 90 nmol/L, 1 ?mol/L 1.4 nmol/L, and 2 nmol/L for MB, TB, NB and BC, respectively. PMID:23510955

Nuchtavorn, Nantana; Smejkal, Petr; Breadmore, Michael C; Guijt, Rosanne M; Doble, Philip; Bek, Fritz; Foret, Frantisek; Suntornsuk, Leena; Macka, Mirek

2013-04-19

341

Regulation of Basal Lateral Membrane Mobility and Permeability to Divalent Cations by Membrane Associated-Protein Kinase C  

PubMed Central

Biological membrane stabilization is essential for maintenance of cellular homeostasis, functionality and appropriate response to various stimuli. Previous studies have showed that accumulation of PKCs in the cell membrane significantly downregulates the membrane fluidity and Ca2+ influxes through the membranes in activated cells. In addition, membrane-inserted form of PKCs has been found in a variety of resting mammalian cells and tissues. This study is aimed to investigate possible role of the endogenous membrane-associated PKCs in the modulation of basal membrane fluidity. Here, we showed that interfering PKC expression by chronic activation of PKC with phorbol myristate acetate (PMA) or shRNA targeting at PKC? lowered the levels of PKC? in cytosol, peripheral membrane and integral membrane pools, while short-term activation of PKC with PMA induced accumulation of PKC? in the membrane pool accompanied by a dramatic decrease in the cytosol fraction. The lateral membrane mobility increased or decreased in accordance with the abundance alterations in the membrane-associated PKC? by these treatments. In addition, membrane permeability to divalent cations including Ca2+, Mn2+ and Ba2+ were also potentiated or abrogated along with the changes in PKC expression on the plasma membrane. Membrane stabilizer ursodeoxycholate abolished both of the enhanced lateral membrane mobility and permeability to divalent cations due to PKC? deficiency, whereas Gö6983, a PKC antagonist, or Gd3+ and 2-aminoethyoxydipheyl borne, two Ca2+ channels blockers, showed no effect, suggesting that this PKC-related regulation is independent of PKC activation or a modulation of specific divalent cation channel. Thus, these data demonstrate that the native membrane-associated PKC? is involved in the maintenance of basal membrane stabilization in resting cells. PMID:24260363

Zhang, Chao; Zheng, Yuanyuan; Chen, Lihong; Chen, Min; Liang, Shenxuan; Lin, Mosi; Luo, Dali

2013-01-01

342

Fatbag Membrane  

USGS Multimedia Gallery

Although oil and water do not normally mix, oil contaminants in waterways can be measured using a special membrane nicknamed a "fatbag." The fatbags absorb many fat-soluble chemicals from the water at a known rate, so they can be used to estimate the concentration of such chemicals....

2010-07-20

343

Membrane magic  

SciTech Connect

The Kansas Power and Light Co.'s La Cyne generating station has found success with membrane filtration water pretreatment technology. The article recounts the process followed in late 2004 to install a Pall Aria 4 microfilter in Unit 1 makeup water system at the plant to produce cleaner water for reverse osmosis feed. 2 figs., 2 photos.

Buecker, B. [Kansas City Power and Light Co. (United States)

2005-09-01

344

Effect of Substrate Composition (C\\/N\\/P ratio) on Microbial Community and Membrane Fouling Tendency of Biomass in Membrane Bioreactors  

Microsoft Academic Search

In this study, biomass characteristics including bacterial community, extracellular polymeric substances (EPS) production, and membrane fouling propensity were examined when the membrane bioreactors (MBRs) were fed with different substrates (i.e., different C\\/N\\/P ratios). Denaturing gradient gel electrophoresis (DGGE) analysis revealed that significant shifts of bacterial communities happened when increasing nitrogen or phosphorus loading in the MBRs, which followed in an

Bing Wu; Shan Yi; Anthony G. Fane

2012-01-01

345

Tromp1, a Putative Rare Outer Membrane Protein, Is Anchored by an Uncleaved Signal Sequence to the Treponema pallidum Cytoplasmic Membrane  

Microsoft Academic Search

Treponema pallidum rare outer membrane protein 1 (Tromp1) has extensive sequence homology with sub- strate-binding proteins of ATP-binding cassette transporters. Because such proteins typically are periplasmic or cytoplasmic membrane associated, experiments were conducted to clarify Tromp1's physicochemical prop- erties and cellular location in T. pallidum. Comparison of the sodium dodecyl sulfate-polyacrylamide gel electrophoresis mobilities of (i) native Tromp1 and Tromp1

DARRIN R. AKINS; ESTHER ROBINSON; DMITRIY SHEVCHENKO; CHRISTOPHER ELKINS; DAVID L. COX; JUSTIN D. RADOLF

1997-01-01

346

Acetate supplementation attenuates lipopolysaccharide-induced neuroinflammation  

PubMed Central

Glyceryl triacetate (GTA), a compound effective at increasing circulating and tissue levels of acetate was used to treat rats subjected to a continual 28 day intra-ventricular infusion of bacterial lipopolysaccharide (LPS). This model produces a neuroinflammatory injury characterized by global neuroglial activation and a decrease in choline acetyltransferase immunoreactivity in the basal forebrain. During the LPS infusion, rats were given a daily treatment of either water or GTA at a dose of 6g/kg by oral gavage. In parallel experiments free-CoA and acetyl-CoA levels were measured in microwave fixed brains and flash frozen heart, liver, kidney and muscle following a single oral dose of GTA. We found that a single oral dose of GTA significantly increased plasma acetate levels by 15 min and remained elevated for up to 4 hr. At 30 min the acetyl-CoA levels in microwave-fixed brain and flash frozen heart and liver were increased at least 2.2-fold. The concentrations of brain acetyl-CoA was significantly increased between 30 and 45 min following treatment and remained elevated for up to 4 hr. The concentration of free-CoA in brain was significantly decreased compared to controls at 240 min. Immunohistochemical and morphological analysis demonstrated that a daily treatment with GTA significantly reduced the percentage of reactive GFAP-positive astrocytes and activated CD11b-positive microglia by 40–50% in rats subjected to LPS-induced neuroinflammation. Further, in rats subjected to neuroinflammation, GTA significantly increased the number of ChAT-positive cells by 40% in the basal forebrain compared to untreated controls. These data suggest that acetate supplementation increases intermediary short chain acetyl-CoA metabolism and that treatment is potentially anti-inflammatory and neuroprotective with regards to attenuating neuroglial activation and increasing ChAT immunoreactivity in this model. PMID:21272004

Reisenauer, Chris J.; Bhatt, Dhaval P.; Mitteness, Dane J.; Slanczka, Evan R.; Gienger, Heidi M.; Watt, John A.; Rosenberger, Thad A.

2011-01-01

347

2-Amino-pyridinium trifluoro-acetate.  

PubMed

The asymmetric unit of the title compound, C(5)H(7)N(2) (+)·C(2)F(3)O(2) (-), contains four independent 2-amino-pyridinium cations and four independent trifluoro-acetate anions. In the crystal structure, these ions are linked by N-H?O hydrogen bonds, forming four cation-anion pairs each containing an R(2) (2)(8) ring motif. The ion pairs are linked into two independent chains along [100] by N-H?O hydrogen bonds. In addition, C-H?O and C-H?F hydrogen bonds and ??? inter-actions [centoid-centroid separation = 3.6007?(17)?Å] are observed. PMID:21580433

Hemamalini, Madhukar; Fun, Hoong-Kun

2010-01-01

348

Capillary electrophoresis separation of rosemary antioxidants from subcritical water extracts  

Microsoft Academic Search

In this work, the possibilities of the combined use of subcritical water extraction (SWE) and capillary electrophoresis (CE) are established through the separation of antioxidants from rosemary ( Rosmarinus officinalis L.). A new CE method is developed that allows the separation of different antioxidants found in the SWE fractions. The CE method is reproducible, efficient and fast, allowing the analysis

Antonio Luis Crego; Elena Ibáñez; Elena García; Raquel Rodríguez de Pablos; Francisco Javier Señoráns; Guillermo Reglero; Alejandro Cifuentes

2004-01-01

349

Column Electrophoresis on the Apollo-Soyuz Test Project  

Microsoft Academic Search

Electrokinetic separation techniques have been widely used for the analysis and characterization of charged materials of biological origin. Under terrestrial conditions preparative methods based on zone electrophoresis, isotachophoresis, and isoelectric focusing are prominent in the purification of charged macromolecules and small particles but have only been of limited usefulness in the separation of biological cells and larger particles. The major

Robert E. Allen; Percy H. Rhodes; Robert S. Snyder; Grant H. Barlow; Milan Bier; Pierluigi E. Bigazzi; Carel J. van Oss; Robert J. Knox; Geoffrey V. F. Seaman; Fortunato J. Micale; John W. Vanderhoff

1977-01-01

350

INDEPENDENT COMPONENT ANALYSIS OF SIMULATED 2D ELECTROPHORESIS GELS  

E-print Network

. of Mathematics and Statistics, Baltimore, MD 21250, VGeorgetown University Medical Center, Dept. of Biostatistics differentially expressed pro- teins in simulated two-dimensional electrophoresis (2DE) gels us- ing spatial, Phoretix]. These methods rely on spot-by-spot analysis and are thus subject to the errors accumulated

Adali, Tulay

351

Gel Electrophoresis--The Easy Way for Students  

ERIC Educational Resources Information Center

This article describes a simple, inexpensive, easy to conduct gel-electrophoresis activity using food dyes. It is an alternative to the more expensive counterparts which require agarose gel, DNA samples, purchased chamber and Tris-borate-EDTA buffer. We suggest some learning activities for senior biology students along with comments on several…

VanRooy, Wilhelmina; Sultana, Khalida

2010-01-01

352

Silver Staining of 2D Electrophoresis Gels Thierry Rabilloud  

E-print Network

Silver Staining of 2D Electrophoresis Gels Thierry Rabilloud CEA-DSV-iRTSV/LCBM and UMR CNRS Head: Silver staining #12;i. Abstract Silver staining is used to detect proteins after electrophoretic are discussed in this chapter, and optimized silver staining protocols are proposed. ii. Key Words: mass

Paris-Sud XI, Université de

353

Enumeration Algorithm for Determination of Binding Constants in Capillary Electrophoresis  

E-print Network

, it can be used to determine binding or dissociation constants of affinity interactions. When CE is usedEnumeration Algorithm for Determination of Binding Constants in Capillary Electrophoresis Ning Fang With more accurate simulation models and more efficient algorithms becoming available, the binding constants

Chen, David D.Y.

354

Multilevel thresholding of gel electrophoresis images using firefly algorithm  

Microsoft Academic Search

Gel electrophoresis (GE) is a process of DNA, RNA and protein molecules separation using electric field applied to a gel matrix. This paper describes the image processing techniques applied on GE image to segment the bands from their background. A few pre-processing steps are applied on the image prior to the segmentation technique for the purpose of removing noise in

M. H. Mohd Noor; A. R. Ahmad; Z. Hussain; K. A. Ahmad; A. R. Ainihayati

2011-01-01

355

Capillary electrophoresis determination of loratadine and related impurities  

Microsoft Academic Search

While HPLC has traditionally been the method of choice for purity determination of pharmaceutical substances, capillary electrophoresis (CE) offers a different selectivity and hence it is a complementary technique to HPLC. Loratadine, an antihistamine, could include in its raw material seven impurities that ought to be separated, identified and quantified for drug development and quality control. As a complementary tool

H Fernández; F. J Rupérez; C Barbas

2003-01-01

356

Predicting interspecific compatibilities in beans (Phaseolus) by seed protein electrophoresis  

Microsoft Academic Search

Seed proteins of 17 wild species of Phaseolus were separated by electrophoresis on SDS polyacrylamide gels. There was very little variation of the protein pattern within most species, while considerable variation among species was evident. Relative interspecific similarities of protein patterns were estimated using Jaccard's similarity index, and a cluster analysis was performed on these values. The resultant dendrogram generally

J. G. Sullivan; G. Freytag

1986-01-01

357

Solid friction in gel electrophoresis S. F. Burlatskya)  

E-print Network

Solid friction in gel electrophoresis S. F. Burlatskya) and John M. Deutch Department of Chemistry 1995 We study the influence of solid frictional forces acting on polymer chains moving in a random environment. We show that the total reduction in the chain tension resulting from the small friction between

Deutch, John

358

History and principles of conductive media for standard DNA electrophoresis.  

PubMed

DNA electrophoresis has been a dominant technique in molecular biology for 30 years. The foundation for this common technique is based on a few simple electrochemical principles. Electrophoretic DNA separation borrowed from existing protein and RNA techniques developed in the 1950s and 1960s. For 30 years, common DNA electrophoretic conductive media remained largely unchanged, with Tris as the primary cation. DNA electrophoresis relies simply upon the negative charge of the phosphate backbone and the ability to distribute a voltage gradient in a sieving matrix. Nevertheless, the conductive properties in DNA electrophoresis are complicated by choices involving voltage, electric current, conductivity, temperature, and the concentration and identity of the ionic species present. Differences among the extant chemical recipes for common conductive media affect central properties. Tris-based buffers, even in optimal form, create a runaway positive feedback loop between heat generation and retention, temperature, conductivity, and current. This is undesirable, leading to limitations on the permissible electric field and to impaired resolution. Recently, we developed low-molarity conductive media to mitigate this positive feedback loop. Such media allow for application of a higher electric field. Applications of DNA electrophoresis can now be reengineered for lower ionic strength, higher field strengths, and lower requirements for heat dissipation. PMID:15351274

Brody, Jonathan R; Kern, Scott E

2004-10-01

359

Polymerase Chain Reaction (PCR) and Gel Electrophoresis Powerpoint  

NSDL National Science Digital Library

The HURI SURI project is developing a regional biotechnology workforce pipeline by expanding and supporting biotechnology research experiences for Jamestown Community College (JCC) undergraduates and disseminating these research experiences and materials to area high school teachers and students. This 15 slide presentation provides an introduction to DNA and explains polymerase chain reactions and gel electrophoresis. Many diagrams are included to help explain the concepts.

2013-08-20

360

Recent advances in the application of capillary electrophoresis to neuroscience  

Microsoft Academic Search

With fast separation times (seconds to minutes), minimal sample requirements (nanoliters to femtoliters), and excellent mass detection limits (femtomole to zeptomole), capillary electrophoresis (CE) is ideally suited for in vitro and in vivo sampling of neurological samples with a high degree of spatial resolution. Advances in extracellular fluid analysis employing improved microdialysis and push–pull perfusion sampling methodologies has enabled the

Paula R. Powell; Andrew G. Ewing

2005-01-01

361

Ultrasensitive near-IR fluorescence detection in capillary zone electrophoresis  

Microsoft Academic Search

Capillary zone electrophoresis (CZE) is a powerful new separation technique which possesses the ability to separate small and large molecules. Due to the small volume of material that is typically loaded onto the column, ultrasensitive detection is often required. We have constructed a laser-induced fluorescence detector appropriate for CZE applications using near- IR fluorescence excitation and detection. Separations of native

Steven A. Soper; Benjamin L. Legendre; James H. Flanagan; Daryl C. Williams; Robert P. Hammer

1994-01-01

362

Supported Lipid Bilayer Electrophoresis: A New Paradigm in Membrane Biophysics and Separations  

E-print Network

M pH 3.3 sodium citrate (left) and 1 mM pH 9.3 Tris (right) ..................................................................................... 28 Figure 4. The mobility of streptavidin labeled with an average of 4.0 dyes/molecule as a function... and function are the driving force behind the research discussed in this dissertation. Indeed, the breakthroughs described herein were motivated by the desire to build tools that biochemists and biophysicists could utilize to elucidate fundamental knowledge...

Pace, Hudson 1982-

2012-11-28

363

Monitoring neurochemical release from astrocytes using in vitro microdialysis coupled with high-speed capillary electrophoresis.  

PubMed

We have developed a novel in vitro approach for monitoring fast neurochemical dynamics in model cell systems using microdialysis sampling coupled with high-speed capillary electrophoresis (CE). Cells from an immortalized astrocyte line (C8-D1A) were cultured in direct contact with the porous membrane of a microdialysis probe. Confocal microscopy was used to confirm cell viability and confluency over the microdialysis sampling region. Small molecules released from the astrocytes were efficiently sampled by the probe due to the direct contact with the membrane. Microdialysis sampling was coupled with online, high-speed CE allowing changes in the dialysate concentration of small molecule amine neurochemicals to be monitored with 20 s temporal resolution. Basal release of a number of important analytes was detected including glycine, taurine, D-serine, and glutamate. The ability of the in vitro microdialysis-CE instrument to monitor dynamic changes in analyte concentration was assessed by transferring a probe cultured with astrocytes from a solution containing artificial cerebrospinal fluid (aCSF) to a high K(+) solution (100 mM K(+)-aCSF). Upon stimulation, the observed concentration of a number of key neurochemicals increased dramatically including glycine (700%), taurine (185%), and serine (215%). Amino acids such as phenylalanine and valine, which are not known to respond to cellular swelling mechanisms, were unaffected by the K(+) stimulation. PMID:23984889

Hogerton, Amy L; Bowser, Michael T

2013-10-01

364

Use of inside-out chloroplast thylakoid membrane vesicles for studying electron transport and membrane structure  

SciTech Connect

Inside-out and right-side-out thylakoid vesicles were isolated from spinach chloroplasts by aqueous-polymer two-phase partitioning following mechanical fragmentation of thylakoid membranes by Yeda press treatment. Externally added plastocyanin stimulated the whole-chain and PSI electron transport rates in the inside-out thylakoid vesicles by about 500 and 350%, respectively, compared to about 50% stimulation for both assays in the fraction enriched in right-side-out vesicles. The electron transport between PSII and PSI in inside-out thylakoid vesicles appears to be interrupted due to plastocyanin release from the thylakoids by the Yeda press treatment, but it was restored by externally added plastocyanin. Acetic anhydride chemical modification and uncoupler-induced proton release from dark-adapted membranes are probes for detecting the sequested proton domains in thylakoid membranes. Both assays were used to find out if inside-out membranes retain metastable, localized proton binding domains. Treatment of dark-maintained inside-out thylakoid membrane vesicles with ({sup 3}H)acetic anhydride showed no uncoupler-induced increase in acetylation of the 33, 24, and 18 kDa polypeptides of the oxygen-evolving-complex, indicating complete loss of the implicated proton domains in these polypeptides. The various steps in the inside-out preparation were studied to discern which steps(s) leads to the loss of the metastable domain proton pool.

Atta-Asafo-Adjei, E.

1987-01-01

365

An evaluation of membrane materials for the treatment of highly concentrated suspended salt solutions in reverse osmosis and nanofiltration processes for desalination  

E-print Network

membrane materials that are most suitable for the process. In the study, a one plate SEPA Cell module by GE Osmonics was used to determine which membranes were most susceptible to fouling and/or membrane hydrolysis. A cellulose acetate (CA), polyamide (PA...

Hughes, Trenton Whiting

2009-05-15

366

Efficient sample clean-up and online preconcentration for sensitive determination of melamine in milk samples by capillary electrophoresis with contactless conductivity detection.  

PubMed

Based on an efficient sample clean-up and field-amplified sample injection online preconcentration technique in capillary electrophoresis with contactless conductivity detection, a new analytical method for the sensitive determination of melamine in milk samples was established. In order to remove the complex matrix interference, which resulted in a serious problem during field-amplified sample injection, liquid-liquid extraction was utilized. As a result, liquid-liquid extraction provides excellent sample clean-up efficiency when ethyl acetate was used as organic extraction by adjusting the pH of the sample solution to 9.5. Both inorganic salts and biological macromolecules are effectively removed by liquid-liquid extraction. The sample clean-up procedure, capillary electrophoresis separation parameters and field-amplified sample injection conditions are discussed in detail. The capillary electrophoresis separation was achieved within 5 min under the following conditions: an uncoated fused-silica capillary, 12 mM HAc + 10 mM NaAc (pH = 4.6) as running buffer, separation voltage of +13 kV, electrokinetic injection of +12 kV × 10 s. Preliminary validation of the method performance with spiked melamine provided recoveries >90%, with limits of detection and quantification of 0.015 and 0.050 mg/kg, respectively. The relative standard deviations of intra- and inter-day were below 6%. This newly developed method is sensitive and cost effective, therefore, suitable for screening of melamine contamination in milk products. PMID:25082754

Ji, Yan-Ling; Chen, Xiao-Wei; Zhang, Zhu-Bao; Li, Jing; Xie, Tian-Yao

2014-10-01

367

Successive analysis of antigen trapping and enzymatic digestion on membrane-immobilized avidin.  

PubMed

Avidin from egg white was migrated toward a cathode of nondenaturing electrophoresis and then immobilized on a polyvinylidene difluoride membrane. Adrenocorticotropic hormone (ACTH) was specifically captured after the biotinylated anti-ACTH antibody was bound to the membrane-immobilized avidin, and the captured ACTH was digested by the biotinylated trypsin on the membrane after extraction. The digested polypeptides from the ACTH were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). These results indicate that target substances can be specifically trapped and digested on membrane-immobilized avidin. PMID:22226789

Shimazaki, Youji; Kohno, Yoshinori

2012-03-01

368

An Investigation on Gel Electrophoresis with Quantum Dots End-labeled DNA  

E-print Network

Invented in the 1950s, gel electrophoresis has now become a routine analytical method to verify the size of nucleic acids and proteins in molecular biology labs. Conventional gel electrophoresis can successfully separate DNA fragments from several...

Chen, Xiaojia

2009-05-15

369

Advantages and limitations of next-generation sequencing technologies: a comparison of electrophoresis and non-electrophoresis methods.  

PubMed

The reference human genome provides an adequate basis for biological researchers to study the relationship between genotype and the associated phenotypes, but a large push is underway to sequence many more genomes to determine the role of various specificities among different individuals that control these relationships and to enable the use of human genome data for personalized and preventative healthcare. The current electrophoretic methodology for sequencing an entire mammalian genome, which includes standard molecular biology techniques for genomic sample preparation and the separation of DNA fragments using capillary array electrophoresis, remains far too expensive ($5 million) to make genome sequencing ubiquitous. The National Human Genome Research Institute has put forth goals to reduce the cost of human genome sequencing to $100,000 in the short term and $1000 in the long term to spur the innovative development of technologies that will permit the routine sequencing of human genomes for use as a diagnostic tool for disease. Since the announcement of these goals, several companies have developed and released new, non-electrophoresis-based sequencing instruments that enable massive throughput in the gathering of genomic information. In this review, we discuss the advantages and limitations of these new, massively parallel sequencers and compare them with the currently developing next generation of electrophoresis-based genetic analysis platforms, specifically microchip electrophoresis devices, in the context of three distinct types of genetic analysis. PMID:19053153

Hert, Daniel G; Fredlake, Christopher P; Barron, Annelise E

2008-12-01

370

Electrophoresis 1994, IS, 591-615 Capillary electrophoresis of DNA in ultradilute polymer solutions 597 Annelise E. Barron  

E-print Network

in the process of mapping and sequencing the human genome. These separations can only be achieved using low Introduction Restriction mapping of chromosomal DNA may require the electrophoretic separation of restriction study and the stage of the mapping effort [l]. DNA electrophoresis is generally conducted in gels

Barron, Annelise E.

371

Structural changes of human serum albumin induced by cadmium acetate.  

PubMed

The structural changes of human serum albumin (HSA) induced by the addition of cadmium acetate were systematically investigated using UV-vis absorption, circular dichroism (CD), synchronous, and three-dimentional (3D) fluorescence methods. The fluorescence spectra suggested the formation of cadmium acetate-HSA complex. UV absorption result indicated that the interaction between cadmium acetate and HSA could lead to the alteration of the protein skeleton. The structural analysis according to CD method showed that the cadmium acetate binding altered HSA conformation with a major reduction of ?-helix, inducing a partial protein unfolding. Synchronous fluorescence spectra suggested that cadmium acetate was situated closer to tryptophan residue compared to tyrosine residues, making tryptophan residue locate in a more hydrophobic environment. 3D fluorescence demonstrated that cadmium acetate could induce the HSA aggregation and cause a slight unfolding of the polypeptide backbone of the protein. PMID:24771482

Chen, Mingmao; Guo, Hao; Liu, Yan; Zhang, Qiqing

2014-06-01

372

Acetate absorption and metabolism in the rabbit hindgut.  

PubMed Central

Acetate disappearance from the loops of the hindgut in the rabbit was evaluated by measuring variations in the concentration of acetate in caecocolonic loops and differences in the arterial and venous plasma. In vivo metabolism in gut and liver tissues was studied after introduction of (1-14C) acetate into caecocolonic loops. The rate of disappearance from the loops was quantitatively significant and showed little variation irrespective of the location in the hindgut. Hindgut tissue metabolised acetate and the intensity of the metabolism varied with the segment studied. The distal position of the gut showed by far the highest acetate uptake. Radioactivity was found in a certain number of free amino acids, organic acids, and sugars. Acetate was mainly converted into aspartate and glutamate. These can be considered as 'stock forms' which can be diverted either towards oxidative metabolism or towards protein synthesis. Images Fig. 1 PMID:4007603

Marty, J F; Vernay, M Y; Abravanel, G M

1985-01-01

373

Effect of medroxyprogesterone acetate (Provera) on ovarian radiosensitivity  

SciTech Connect

Medroxyprogesterone acetate (Provera) is a drug that is commonly given to young women with cancer during chemotherapy and radiation to control heavy bleeding associated with anovulation. Because hypothalamic-pituitary-ovarian suppression has been associated with ovarian protection from the effects of chemotherapy and medroxyprogesterone acetate has been identified as a radiosensitizing agent, we explored the effects of medroxyprogesterone acetate on a rat model with known radiation injury characteristics. Sprague-Dawley rats were treated with medroxyprogesterone acetate or vehicle from day 22 to day 37 of life and were either irradiated or sham-irradiated on day 30 of life and then killed on day 44. Radiation with medroxyprogesterone acetate administration produced a greater loss in preantral and healthy control follicles than in control follicles. No suppression of luteinizing hormone or follicle-stimulating hormone had occurred by day 30 but ovarian glutathione content was reduced. These findings indicate that the administration of medroxyprogesterone acetate with radiotherapy may enhance ovarian injury.

Jarrell, J.; YoungLai, E.V.; McMahon, A.; Barr, R.; O'Connell, G.; Belbec, L.

1989-04-01

374

Nutrient requirements for high rate conversion of acetate to methane  

Microsoft Academic Search

In this research, nutrient requirements for high rate conversion of acetate to methane were examined with acetate enrichment cultures at 35°C. By employing a pH stat as the cultivation system, the pH and acetate concentration were maintained, respectively, at about 6.8 and greater than or equal to 2000 mg\\/l in the reactor. Ni and Fe limitation in the pH stat

Takashima

1987-01-01

375

Mesophilic syntrophic acetate oxidation during methane formation in biogas reactors  

Microsoft Academic Search

The reaction pathway for the formation of methane from acetate was investigated in sludge from 13 different biogas reactors. By following the conversion of [2-14C]acetate and [14C]bicarbonate it was shown that methane formation by syntrophic acetate oxidation was the dominating mechanism for acetotrophic methanogenesis in sludge containing high levels of salts, mainly ammonium, and volatile fatty acids. In one biogas

Anna Schnürer; Gerhard Zellner; Bo H. Svensson

1999-01-01

376

08-136.doc; 3/10/09 Electrophoresis, a technique which uses electrical  

E-print Network

in laboratories. Electrophoresis work poses potential electrical, chemical and physical safety hazards. ELECTRICAL SAFETY Electrophoresis equipment can pose significant electrical hazards in the laboratory. Typical08-136.doc; 3/10/09 Electrophoresis, a technique which uses electrical energy to separate molecules

Ford, James

377

A model for Joule heating-induced dispersion in microchip electrophoresis  

E-print Network

A model for Joule heating-induced dispersion in microchip electrophoresis Yi Wang,a Qiao Lin-uniform temperature distributions in the channel resulting from Joule heating, and then determine variations by Joule heating effects in electrophoresis microchannels. In electrophoresis, an electric field is used

Lin, Qiao

378

A Rice Membrane Calcium-Dependent Protein Kinase 1s lnduced by Gibberellin  

Microsoft Academic Search

A rice (Oryza sativa) seed plasma-membrane calcium-dependent serine\\/threonine protein kinase (CDPK) has been partially purified. Comparing results in seeds that were treated with and without the plant hormone gibberellin (CA) for 10 min showed that rice CDPK was highly induced by GA. After separating solubilized membrane proteins by sodium dodecyl sulfate-gel electrophoresis, followed by renaturation, a radiolabeled phosphoprotein band of

Mahmoud Abo-El-Saad; Ray Wu

379

Characteristics and Molecular Mechanism of Adhesion Proteins on Reused Hemodialysis Membranes  

Microsoft Academic Search

In order to study the mechanism of protein adhesion on the Fresenius F6 polysulfone membrane dialyzer, two-dimensional gel electrophoresis, LC-ESI-MS\\/MS and bioinformatics methods were used to analyze the protein which adhered to the dialyzer membrane. Six of the adhered proteins account for more than 50% of the total 179 proteins, i.e. ficolin precursor, complement C3 precursor, 3 variants of MASP1

Xiulin Xu; Yujing Yang; Naishuo Zhu

2009-01-01

380

21 CFR 522.1410 - Sterile methylprednisolone acetate suspension.  

Code of Federal Regulations, 2010 CFR

...with methylprednisolone acetate, as with other corticoids, is contraindicated in animals with arrested tuberculosis, peptic ulcer, and Cushing's syndrome. The presence of active tuberculosis, diabetes mellitus, osteoporosis, renal...

2010-04-01

381

21 CFR 522.1410 - Sterile methylprednisolone acetate suspension.  

Code of Federal Regulations, 2011 CFR

...with methylprednisolone acetate, as with other corticoids, is contraindicated in animals with arrested tuberculosis, peptic ulcer, and Cushing's syndrome. The presence of active tuberculosis, diabetes mellitus, osteoporosis, renal...

2011-04-01

382

Aryl Acetate Phase Transfer Catalysis: Method and Computation Studies.  

E-print Network

??Brief explanation and history of cinchona based Phase Transfer Catalysis (PTC). Studied aryl acetates in PTC, encompassing napthoyl, 6-methoxy napthoyl, phenyl and protected 4-hydroxy phenyl… (more)

Binkley, Meisha A

2011-01-01

383

Polypyrrole based strong acid catalyst for acetalization  

NASA Astrophysics Data System (ADS)

Novel polypyrrole based acid catalyst has been synthesized through the neutralization reaction of polypyrrole and sulfuric acid. The polypyrrole based acid owned the acidity as high as 6.0 mmol/g, which was much higher than that of the traditional solid acids such as Nafion and Amberlyst-15 (0.8 mmol/g). The catalytic activities of the novel solid acid were investigated through the acetalization. The results showed that the novel solid acid held high activities for the reactions. Furthermore, the recycled activities of the catalyst indicated that the solid acid owned high stability during the catalytic process and little acid sites dropped from polypyrrole. The high acidity and stability made the novel polypyrrole based acid hold great potential for the green chemical processes.

Liang, Xuezheng; Cheng, Yuxiao; Qi, Chenze

2011-09-01

384

Synthesis and regeneration of lead (IV) acetate  

SciTech Connect

Lead acetate [Pb(O{sub 2}CMe){sub 4}] was easily synthesized from a warm solution of Pb{sub 3}O{sub 4}, HO{sub 2}CMe and O(OCMe){sub 2} following literature preparations when the appropriate measures to minimize water contamination were followed. Furthermore, Pb(O{sub 2}CMe){sub 4} which has been decomposed (evidenced by the appearance of a purple color due to oxidation) can be regenerated using a similar preparatory route. Introduction of Pb(O{sub 2}CMe){sub 4} from the two routes outlined above into the IMO process for production of PZT thin films gave films with comparable ferroelectric properties to commercially available Pb(O{sub 2}CMe){sub 4} precursors. However, the freshly synthesized material yields PZT films with better properties compared to the recycled material.

Boyle, T.J.; Al-Shareef, H.N.; Moore, G.J. [Sandia National Labs., Albuquerque, NM (United States). Advanced Materials Lab.

1996-11-01

385

DEOXYRIBONUCLEIC ACID HYBRIDS OF ACETIC ACID BACTERIA  

PubMed Central

De Ley, J. (State University, Ghent, Belgium), and S. Friedman. Deoxyribonucleic acid hybrids of acetic acid bacteria. J. Bacteriol. 88:937–945. 1964.—Deuterated N15-labeled deoxyribonucleic acid (DNA) from Acetobacter aceti (mesoxydans 4) forms hybrids with ordinary DNA from other species of this genus (A. xylinum, A. pasteurianus, A. estunensis, and possibly A. xylinoides) when the guanine plus cytosine base composition does not vary by more than 1 to 2%. Beyond this limit (A. aceti Ch31 and A. muciparus 5) no hybrids are formed. The hybrids are apparently derived from an asymmetrical part of the compositional distribution. The results lend strength to the concept of a genetic species rather than to a division of a genus into sharply separated species, based on small phenotypic differences. Taxonomic implications are discussed. PMID:14219057

De Ley, J.; Friedman, S.

1964-01-01

386

The Gene yjcG, Cotranscribed with the Gene acs, Encodes an Acetate Permease in Escherichia coli  

PubMed Central

We isolated an Escherichia coli mutant strain that suppresses the glycolate-negative phenotype of a strain deficient in both GlcA and LldP transporters of this compound. This suppressing phenotype was assigned to yjcG, a gene whose function was previously unknown, which was found to encode a membrane protein able to transport glycolate. On the basis of sequence similarity, the yjcG gene product was classified as a member of the sodium:solute symporter family. Northern experiments revealed that yjcG is cotranscribed with its neighbor, acs, encoding acetyl coenzyme A synthetase, which is involved in the scavenging acetate. The fortuitous presence of an IS2 element in acs, which impaired yjcG expression by polarity in our parental strain, allowed us to conclude that the alternative glycolate carrier became active after precise excision of IS2 in the suppressed strain. The finding that yjcG encodes a putative membrane carrier for glycolate and the cotranscription of yjcG with acs suggested that the primary function of the yjcG gene product (proposed gene name, actP) could be acetate transport and allowed us to define an operon involved in acetate metabolism. The time course of [1,2-14C]acetate uptake and the results of a concentration kinetics analysis performed with cells expressing ActP or cells deficient in ActP supported the the hypothesis that this carrier is an acetate transporter and suggested that there may be another transport system for this monocarboxylate. PMID:14563880

Gimenez, Rosa; Felisa Nunez, Maria; Badia, Josefa; Aguilar, Juan; Baldoma, Laura

2003-01-01

387

Effects of short solids retention time on microbial community in a membrane bioreactor  

Microsoft Academic Search

Effects of operating lab-scale nitrifying membrane bioreactors (MBR) at short solids retention times (SRT=3, 5 and 10d) were presented with focus on reactor performance and microbial community composition. The process was capable of achieving over 87% removal of ammonia and 95% removal of chemical oxygen demand (COD), almost regardless of SRT. The denaturing gradient gel electrophoresis (DGGE) analysis shown that

Liang Duan; Ivan Moreno-Andrade; Chun-lin Huang; Siqing Xia; Slawomir W. Hermanowicz

2009-01-01

388

Comprehensive Proteomic Analysis of Membrane Proteins in Toxoplasma gondii*  

PubMed Central

Toxoplasma gondii (T. gondii) is an obligate intracellular protozoan parasite that is an important human and animal pathogen. Experimental information on T. gondii membrane proteins is limited, and the majority of gene predictions with predicted transmembrane motifs are of unknown function. A systematic analysis of the membrane proteome of T. gondii is important not only for understanding this parasite's invasion mechanism(s), but also for the discovery of potential drug targets and new preventative and therapeutic strategies. Here we report a comprehensive analysis of the membrane proteome of T. gondii, employing three proteomics strategies: one-dimensional gel liquid chromatography-tandem MS analysis (one-dimensional gel electrophoresis LC-MS/MS), biotin labeling in conjunction with one-dimensional gel LC-MS/MS analysis, and a novel strategy that combines three-layer “sandwich” gel electrophoresis with multidimensional protein identification technology. A total of 2241 T. gondii proteins with at least one predicted transmembrane segment were identified and grouped into 841 sequentially nonredundant protein clusters, which account for 21.8% of the predicted transmembrane protein clusters in the T. gondii genome. A large portion (42%) of the identified T. gondii membrane proteins are hypothetical proteins. Furthermore, many of the membrane proteins validated by mass spectrometry are unique to T. gondii or to the Apicomplexa, providing a set of gene predictions ripe for experimental investigation, and potentially suitable targets for the development of therapeutic strategies. PMID:20935347

Che, Fa-Yun; Madrid-Aliste, Carlos; Burd, Berta; Zhang, Hongshan; Nieves, Edward; Kim, Kami; Fiser, Andras; Angeletti, Ruth Hogue; Weiss, Louis M.

2011-01-01

389

Role of apoptosis in uranyl acetate-induced acute renal failure and acquired resistance to uranyl acetate  

Microsoft Academic Search

Role of apoptosis in uranyl acetate-induced acute renal failure and acquired resistance to uranyl acetate.BackgroundWe have previously reported that animals recovering from uranyl acetate (UA)-induced acute renal failure (ARF) were resistant to subsequent insult. Recent evidence suggests that apoptosis participates in tubular damage. We investigated the role of apoptosis in UA-induced ARF and attenuation of ARF in acquired resistance to

Koji Sano; Yoshihide Fujigaki; Takehiko Miyaji; Naoki Ikegaya; Kazuhisa Ohishi; Katsuhiko Yonemura; Akira Hishida

2000-01-01

390

Phase and reaction equilibria of acetic acid–1-pentanol–water– n-amyl acetate system at 760 mm Hg  

Microsoft Academic Search

The esterification reaction of acetic acid and alcohol is one of the processes applying reactive distillation technology. It is known that the thermodynamic properties are essential to chemical process design. In this study, the thermodynamic behaviors of vapor–liquid equilibrium (VLE) and reaction equilibrium of acetic acid, 1-pentanol, n-amyl acetate, and water mixture were determined experimentally. Since the present esterification reaction

Liang-sun Lee; Shen-jang Liang

1998-01-01

391

Multiple myeloma: a case of atypical presentation on protein electrophoresis.  

PubMed

Multiple myeloma is a group of B-cell disorders resulting in the secretion of a specific and unique monoclonal immunoglobulin (M-protein). Protein electrophoresis is advised whenever multiple myeloma is suspected. The monoclonal protein migrates as a single entity in the electric field and is detected by the non-specific protein stain as a more intensely stained band superimposed on the usual protein pattern. The M-protein usually migrates in the gamma or beta region of the normal protein pattern; very rarely it may appear in the ?2 or even in ?1 region. Here we have given an atypical case presentation where the patient with multiple myeloma presented with two M-spike one each in ?2 and ?-globulin region on agarose gel protein electrophoresis with hypoglobulinemia but with reversed A:G ratio. PMID:23277721

Dash, Nihar Ranjan; Mohanty, Biswajit

2012-01-01

392

SDS capillary gel electrophoresis of proteins in microfabricated channels  

PubMed Central

Analysis of variations in the concentrations or structures of biomolecules (e.g., mRNAs, proteins, peptides, natural products) that occur either naturally or in response to environmental or genetic perturbations can provide important insight into complex biological processes. Many biological samples are mixtures that require a separation step before quantitation of variations in the individual components. Two-dimensional denaturing gel electrophoresis has been used very effectively to separate complex mixtures of proteins, but it is time consuming and requires considerable amounts of sample. Microchannel-based separations have proven very effective in rapidly separating small amounts of nucleic acids; more recently, isoelectric focusing of proteins also has been adapted to the microchannel format. Here, we describe microchannel-based SDS capillary gel electrophoresis of proteins and demonstrate the speed and high resolution it provides. This development is an important step toward the miniaturization and integration of multidimensional and array separation methods for complex protein mixtures. PMID:10318890

Yao, Shao; Anex, Deon S.; Caldwell, W. Brett; Arnold, Don W.; Smith, Katherine B.; Schultz, Peter G.

1999-01-01

393

Determination of synthetic food dyes by capillary electrophoresis.  

PubMed

A method for the determination of synthetic tar dyes used as food additives using capillary electrophoresis with photodiode-array detection was investigated. The dyes Erythrosine (R-3), Phloxine (R-104), Rose Bengal (R-105), Acid Red (R-106), Amaranth (R-2), New Coccine (R-102) and Allura Red AC (R-40) were separated on a capillary column (50 cm x 75 microns I.D.) and identified from the absorbance spectra of each peak. The electrophoresis buffer used was a mixture of 25 mM sodium phosphate buffer and 25 mM sodium borate buffer (1:1) (pH 8.0) containing 10 mM sodium dodecyl sulfate (SDS). Substitution of beta-cyclodextrin for SDS in the electrolyte buffer was effective for the separation of R-2 and R-102. This modified method could be employed as an additional assay method for these two dyes. PMID:7981834

Suzuki, S; Shirao, M; Aizawa, M; Nakazawa, H; Sasa, K; Sasagawa, H

1994-10-01

394

Effects of coating rectangular microscopic electrophoresis chamber with methylcellulose  

NASA Technical Reports Server (NTRS)

One of the biggest problems in obtaining high accuracy in microscopic electrophoresis is the parabolic flow of liquid in the chamber due to electroosmotic backflow during application of the electric field. In chambers with glass walls the source of polarization leading to electroosmosis is the negative charge of the silicare and other ions that form the wall structure. It was found by Hjerten, who used a rotating 3.0 mm capillary tube for free zone electrophoresis, that precisely neutralizing this charge was extremely difficult, but if a neutral polymer matrix (formaldehyde fixed methylcellulose) was formed over the glass (quartz) wall the double layer was displaced and the viscosity at the shear plane increased so that electroosmotic flow could be eliminated. Experiments were designed to determine the reliability with which methylcellulose coating of the Zeiss Cytopherometer chamber reduced electroosmotic backflow and the effect of coating on the accuracy of cell electrophoretic mobility (EPN) determinations. Fixed rat erythrocytes (RBC) were used as test particles.

Plank, L. D.

1985-01-01

395

Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by an enzyme preparation from Zea mays  

NASA Technical Reports Server (NTRS)

Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

Reinecke, D. M.; Bandurski, R. S.

1988-01-01

396

Thermal decomposition of pyridine-substituted cobaltic acetate in acetic acid.  

PubMed

The thermal decomposition of [py(3)Co(3)O(OAc)(5)OH][PF(6)] in acetic acid solution in the absence of oxygen produced carbon dioxide, methane, carbon monoxide, picoline, and formic acid as the major products. The ratio of the products was affected by the water concentration and acidity of the mixture. Increased water concentration caused a decrease in methane and an increase in carbon monoxide. Decreased acidity resulted in an increase in methane and a decrease in carbon monoxide. Isotopic labeling experiments showed that some of the carbon monoxide originated as the carboxyl group of the acetic acid. Labeling experiments also showed that formaldehyde and formic acid could be converted to carbon monoxide under the reaction conditions. Two pathways leading to the formation of carbon monoxide were proposed; one involving the decomposition of glyoxylic acid and another involving the oxidation of the methyl radical by cobalt(III). PMID:20397646

Sumner, Charles E; Little, James; Howard, Adam S; Liang, Weimin C

2010-05-17

397

Theoretical studies of molecular structure and vibrational spectra of melaminium acetate acetic acid solvate monohydrate.  

PubMed

The molecular geometry and vibrational frequencies of melaminium acetate acetic acid solvate monohydrate in the ground state have been calculated by using the Hartree-Fock (HF) and density functional method (B3LYP) with 6-31++G(d,p) basis set. The results of the optimized molecular structure are presented and compared with the experimental X-ray diffraction. The molecule contains the weak hydrogen bonds of N-H...O and O-H...O types, and those bonds are calculated with HF and DFT method. The computed vibrational frequencies were used to determine the types of molecular motions associated with each of the experimental bands observed. In addition, calculated results are related to the linear correlation plot of computed data versus experimental geometric parameters and IR data. PMID:20692201

Pekparlak, A; Avci, D; Cömert, H; Atalay, Y

2010-10-15

398

High-resolution, continuous-flow electrophoresis in microgravity  

NASA Technical Reports Server (NTRS)

Approximate expressions which will allow estimation of performance enhancement in reduced gravity and will direct optimization of the various design parameters for a continuous flow electrophoresis system was devised. Other topics discussed include: (1) temperature and velocity distribution; (2) input power limitations in reduced gravity; and (3) effect of band distortion on resolution. A comparision of resolution for terrestrial and reduced gravity operations was also discussed.

Rhodes, P. H.

1978-01-01

399

The instantaneous monitoring of polyacrylamide gels during electrophoresis.  

PubMed Central

The advantages of being able to see protein zones in a gel during electrophoresis (and hence before staining) are pointed out, and a method is described which depends on local increments of refractive index in these zones. The use of local increments of refractive index in polyacrylamide gels for measuring protein concentrations in zones during electrophoresis is briefly considered; it is found that such increments are greater than would be expected from the amount of protein when sodium dodecyl sulphate is present. The enhancement depends on conditions and time of running. This makes quantitative estimates difficult, but the sensitivity of detection of protein zones by observations based on refractive-index changes is greatly increased by this property of sodium dodecyl sulphate. Methods are described for making optically uniform gels (both with uniform and with graded concentrations of polyacrylamide), necessary for observation of small changes in refractive index. A simple dark-field system of observation is described. Examples are given showing protein samples observed with the system during electrophoresis and compared with the same gel stained with Coomassie Blue after completion of the run. Under optimal conditions the optical method is comparable in sensitivity with staining. With the proteins of lower mol.wt. (approx. 15000), the optical method is not so sensitive, becoming less sensitive with longer running time. This loss of sensitivity is greatly decreased by using more concentrated polyacrylamide gels, and graded gels are therefore more suitable for optical observation than are uniform gels. The observation of protein zones during electrophoresis adds nothing to the time needed for making a stained gel and gives much information long before it can be obtained from the stained gel. Images PLATE 1 PLATE 2 PMID:1008832

Elliott, A

1976-01-01

400

Analysis of illicit amphetamine seizures by capillary zone electrophoresis  

Microsoft Academic Search

Capillary zone electrophoresis was applied for the determination of amphetamine and related substances in seized drugs. A buffer made of 0.1 M phosphoric acid adjusted to pH 3.0 with triethanolamine was selected. With this background electrolyte, triethanolamine is adsorbed to the capillary wall and the electroosmotic flow is reversed. This gives rise to peaks with good symmetry, high efficiency and

Véronique Piette; Frans Parmentier

2002-01-01

401

Analysis of Drosophila chromosome 4 using pulsed field gel electrophoresis  

Microsoft Academic Search

Previous estimates of the size ofDrosophila melanogaster chromosome4 have indicated that it is 1% to 4% of the genome or ~6 Mb. We have used pulsed field gel electrophoresis (PFGE) to separate megabase-sized molecules ofD. melanogaster chromosomal DNA. Southern blots of these gels were probed with DNA fragments from thecubitus interruptus andzfh-2 genes, which are located on chromosome4. They each

John Locke; Heather E. McDermid

1993-01-01

402

Effective charge of bovine serum albumin determined by electrophoresis NMR  

Microsoft Academic Search

The effective charge of bovine serum albumin in aqueous solution is determined by dynamic NMR as a function of pH. The effective charge results from the degree of dissociation varying with pH and the local counterion condensation. While the hydrodynamic friction is determined from the diffusion coefficient measured by pulsed-field gradient NMR, the electrophoretic mobility is determined by electrophoresis NMR.

Ute Böhme; Ulrich Scheler

2007-01-01

403

Nanomolar determination of aminated sugars by capillary electrophoresis  

Microsoft Academic Search

A procedure is described for the determination of aminated monosaccharides at nanomolar concentrations by derivatization with the fluorogenic reagent 3-(p-carboxybenzoyl)quinoline-2-carboxyaldehyde (CBQCA) to produce a fluorescent derivative that can be identified and detected by capillary electrophoresis with laser-induced fluorescence detection. Labeling conditions that favor the formation of the CBQCA-aminated sugar derivative over secondary fluorescent products were chosen. Samples as dilute as

Yanni Zhang; Edgar Arriaga; Paul Diedrich; Ole Hindsgaul; Norman J. Dovichi

1995-01-01

404

Continuous wave-based multiphoton excitation fluorescence for capillary electrophoresis  

Microsoft Academic Search

It was reported that a novel detection method, continuous wave (CW)-based multiphoton excitation (MPE) fluorescence detection with diode laser (DL), has been firstly proposed for capillary electrophoresis (CE). Special design of end-column detection configuration proved to be superior to on-column type, considering the detection sensitivity. Three different kinds of fluorescent tags that were widely used as molecular label in bio-analysis,

Sheng Chen; Bi-Feng Liu; Ling Fu; Tao Xiong; Tiancai Liu; Zhihong Zhang; Zhen-Li Huang; Qiang Lu; Yuan-Di Zhao; Qingming Luo

2006-01-01

405

Attempt to run urinary protein electrophoresis using capillary technique.  

PubMed

The study of urinary protein has a predominant place in the diagnosis of kidney disease. The most common technique is agarose gel electrophoresis (AGE). For several years, the technique of choice applied to the analysis of serum proteins has been CE, a system that uses capillary fused silica, subjected to high voltage to separate and measure serum proteins. The purpose of this paper was to perform capillary electrophoresis on urinary proteins which, at present, are not interpretable due to the many nonspecific peaks visible when using gel electrophoresis. In order to carry out our research, we used a capillary V8 analyzer together with an agarose gel system from the same company. AGE was taken as the reference method, for which urine was used without any pretreatment. For the V8 system, urine was subjected to purification on granular-activated carbon and then inserted into the V8 analyzer, selecting a program suitable for liquids with low protein content. We examined 19 urine samples collected over 24 hrs from both hospitalized and external patients with different types of proteinuria plus a serum diluted 1/61 considered as a control to recognize the bands. Both methods showed the same protein fractions and classified the proteinuria in a similar way. PMID:25074652

Falcone, Michele

2014-10-01

406

New analytical portable instrument for microchip electrophoresis with electrochemical detection.  

PubMed

A new portable instrument that includes a high voltage power supply, a bipotentiostat, and a chip holder has been especially developed for using microchips electrophoresis with electrochemical detection. The main unit of the instrument has dimensions of 150 x 165 x 70 mm (wxdxh) and consists of a four-outputs high voltage power supply with a maximum voltage of +/-3 KV and an acquisition system with two channels for dual amperometric (DC or pulsed amperometric detection) detection. Electrochemical detection has been selected as signal transduction method because it is relatively easily implemented, since nonoptical elements are required. The system uses a lithium-ion polymer battery and it is controlled from a desktop or laptop PC with a graphical user interface based on LabVIEW connected by serial RS232 or Bluetooth. The last part of the system consists of a reusable chip holder for housing the microchips, which contain all the electrical connections and reservoirs for making the work with microchips easy. The performance of the new instrument has been evaluated and compared with other commercially available apparatus using single- and dual-channel pyrex microchips for the separation of the neurotransmitters dopamine, epinephrine, and 3,4-dihydroxy-L-phenyl-alanine. The reduction of the size of the instrument has not affected the good performance of the separation and detection using microchips electrophoresis with electrochemical detection. Moreover, the new portable instrument paves the way for in situ analysis making the use of microchips electrophoresis easier. PMID:20665922

Fernández-la-Villa, Ana; Pozo-Ayuso, Diego F; Castaño-Alvarez, Mario

2010-08-01

407

Multiwavelength fluorescence detection for DNA sequencing using capillary electrophoresis.  

PubMed Central

Multiwavelength detection of laser induced fluorescence for dideoxynucleotide DNA sequencing with four different fluorophores and separation by capillary gel electrophoresis is described. A cryogenically cooled, low readout noise, 2-dimensional charge-coupled device is used as a detector for the on-line, on-column recording of emission spectra. The detection system has no moving parts and provides wavelength selectivity on a single detector device. The detection limit of fluorescently labeled oligonucleotides meets the high sensitivity requirements for capillary DNA sequencing largely due to the efficient operation of the CCD detector with a 94% duty cycle. Using the condition number as a selectivity criterion, multiwavelength detection provides better analytical selectivity than detection with four bandpass filters. Monte Carlo studies and analytical estimates show that base assignment errors are reduced with peak identification based on entire emission spectra. High-speed separation of sequencing samples and the treatment of the 2-dimensional electropherogram data is presented. Comparing the DNA sequence of a sample separated by slab gel electrophoresis with sequence from capillary gel electrophoresis and multiwavelength detection we find no significant difference in the amount of error attributable to the instrumentation. Images PMID:1923763

Karger, A E; Harris, J M; Gesteland, R F

1991-01-01

408

Visualization of DNA molecules in time during electrophoresis  

NASA Technical Reports Server (NTRS)

For several years individual DNA molecules have been observed and photographed during agarose gel electrophoresis. The DNA molecule is clearly the largest molecule known. Nevertheless, the largest molecule is still too small to be seen using a microscope. A technique developed by Morikawa and Yanagida has made it possible to visualize individual DNA molecules. When these long molecules are labeled with appropriate fluorescence dyes and observed under a fluorescence microscope, although it is not possible to directly visualize the local ultrastructure of the molecules, yet because they are long light emitting chains, their microscopic dynamical behavior can be observed. This visualization works in the same principle that enables one to observe a star through a telescope because it emits light against a dark background. The dynamics of individual DNA molecules migrating through agarose matrix during electrophoresis have been described by Smith et al. (1989), Schwartz and Koval (1989), and Bustamante et al. (1990). DNA molecules during agarose gel electrophoresis advance lengthwise thorough the gel in an extended configuration. They display an extension-contraction motion and tend to bunch up in their leading ends as the 'heads' find new pores through the gel. From time to time they get hooked on obstacles in the gel to form U-shaped configurations before they resume their linear configuration.

Lubega, Seth

1991-01-01

409

Determination of acid dissociation constants by capillary electrophoresis.  

PubMed

Capillary electrophoresis affords a simple, automated approach for the measurement of pKa values in the range 2-11 at a throughput of less than 1 h per sample per instrument. Agreement with literature values is usually within 0.20 log units with a precision better than 0.07 log units. The attractive features of capillary electrophoresis for pKa measurements are: (1) conventional instrumentation with a high level of automation are suitable for all measurements; (2) because it is a separation method samples need not be of high purity; (3) samples of low water solubility with suitable chromophores are easily handled (detection limits in the microM range); (4) sample consumption per measurement is in the microgram range; and (5) since only mobilities are measured, exact knowledge of concentrations is not needed. The general approach can be extended to pKa measurements in aqueous-organic solvent mixtures and non-aqueous solvents with suitable calibration. The widespread use of absorbance detection in capillary electrophoresis means that the sample must have a suitable chromophore for detection. The main source of controllable error is the accuracy of buffer standardization and their stability in use, and uncontrollable error, the retentive interactions of the sample with the column wall. The latter seems to be a rare problem in practice for typical operating conditions. PMID:15214681

Poole, Salwa K; Patel, Sneha; Dehring, Karen; Workman, Heather; Poole, Colin F

2004-05-28

410

Resolution of structural isomers of sialylated oligosaccharides by capillary electrophoresis.  

PubMed

The resolution of structural isomers in mixtures of oligosaccharides is often challenging. Capillary electrophoresis was employed to separate three sets of structural isomers of sialylated oligosaccharides found in human milk and bovine colostrum. Different running buffers were necessary to achieve optimal baseline resolution. To resolve 3'- and 6'-sialyllactoses, 0.2 M aqueous sodium phosphate containing 40% methanol as an organic modifier was used as a running buffer. To resolve 3'- and 6'-sialyllactosamines, 0.4 M aqueous sodium phosphate without organic modifier was used. Baseline resolution of sialyllacto-N-tetraose-a and -b and sialyllacto-N-neotetraose-c was achieved with a 0.4 M Tris-HCl buffer containing 250 mM sodium dodecyl sulfate and 10% methanol as the organic modifier. Thus, each of these sets of structural isomers of sialylated oligosaccharides required a unique running buffer with respect to buffer type, concentration, pH, presence of organic modifiers, and surfactants. Similar electrophoresis conditions may be useful for resolving and analyzing other structural isomers of acidic oligosaccharides by capillary electrophoresis. PMID:11471815

Shen, Z; Warren, C D; Newburg, D S

2001-07-01

411

Capillary electrophoresis determination of nonsteroidal anti-inflammatory drugs in wastewater using hollow fiber liquid-phase microextraction.  

PubMed

The presence of pharmaceuticals in the environment due to growing worldwide consumption has become an important problem that requires analytical solutions. This paper describes a CE determination for several nonsteroidal anti-inflammatory drugs (ibuprofen, naproxen, ketoprofen, diclofenac, ketorolac, aceclofenac and salicylic acid) in environmental waters using hollow fiber membrane liquid-phase microextraction. The extraction was carried out using a polypropylene membrane supporting dihexyl ether and the electrophoretic separation was performed in acetate buffer (30?mM, pH 4) using ACN as the organic modifier. Detection limits between 0.25 and 0.86?ng/mL were obtained, respectively. The method could be applied to the direct determination of the seven anti-inflammatories in wastewaters, and five of them have been determined or detected in different urban wastewaters. PMID:23479790

Villar Navarro, Mercedes; Ramos Payán, María; Fernández-Torres, Rut; Bello-López, Miguel A; Callejón Mochón, Manuel; Guiráum Pérez, Alfonso

2011-08-01

412

Origin and fate of acetate in an acidic fen.  

PubMed

Acetate is a central intermediate in the anaerobic degradation of organic matter, and the resolution of its metabolism necessitates integrated strategies. This study aims to (1) estimate the contribution of acetogenesis to acetate formation in an acidic fen (pH ~ 4.9), (2) assess the genetic potential for acetogenesis targeting the fhs gene encoding formyltetrahydrofolate synthetase (FTHFS) and (3) unravel the in situ turnover of acetate using stable carbon isotope pore-water analysis. H(2)/CO(2)-supplemented peat microcosms yielded (13)C-depleted acetate (-37.2‰ vs. VPDB (Vienna Peedee belemnite standard) compared with -14.2‰ vs. VPDB in an unamended control), indicating the potential for H(2)-dependent acetogenesis. Molecular analysis revealed a high diversity and depth-dependent distribution of fhs phylotypes with the highest number of operational taxonomic units in 0-20 cm depth, but only few and distant relationships to known acetogens. In pore waters, acetate concentrations (0-170 ?M) and ?(13)C-values varied widely (-17.4‰ to -3.4‰ vs. VPDB) and did not indicate acetogenesis, but pointed to a predominance of sinks, which preferentially consumed (12)C-acetate, like acetoclastic methanogenesis. However, depth profiles of methane and ?(13)C(CH4) revealed a temporarily and spatially restricted role of this acetate sink and suggest other processes like sulfate and iron reduction played an important role in acetate turnover. PMID:22404042

Hädrich, Anke; Heuer, Verena B; Herrmann, Martina; Hinrichs, Kai-Uwe; Küsel, Kirsten

2012-08-01

413

Cyclization of ?-terpenols and their acetates by fluorosulfonic acid  

Microsoft Academic Search

It has been shown that the superacid cyclization of ?-terpenols and their acetates takes place with structural selectivity\\u000a and chemo- and stereospecificity and leads to cyclic isoprenoids with higher yields than the cyclization of the corresponding\\u000a ?-terpenols and their acetates.

N. D. Ungur; N. P. Popa; Nguen Van Tuen; P. F. Vlad

1993-01-01

414

Addition of acetic acid to styrene catalyzed by ion exchanger  

Microsoft Academic Search

The possibility of preparation of 1-phenylethyl acetate by direct addition of acetic acid to styrene catalyzed by Ostion KS in the acid cycle has been investigated. The reaction is accompanied by the formation of higher molecular compounds. The effect of temperature, mole ratio of the starting compounds, stabilization of styrene, amount of the catalyst and of its repeated use on

L. ?ervený; A. Marhoul; J. Kozel

1988-01-01

415

Interaction between acetate fed sulfate reducers and methanogens  

Microsoft Academic Search

During anaerobic treatment of sulfate containing wastewaters, sulfate reducing bacteria (SRB) and methane producing bacteria (MPB) can compete for acetate as the common primary substrate. Since acetate is an intermediate of anaerobic degradation of complex wastes, the outcome of the competition between SRB and MPB can affect the treatment efficiency. The objective of this research was to determine the effects

S. K. Bhattacharya; V. Uberoi; M. M. Dronamraju

1996-01-01

416

Uptake and turnover of acetate in hypersaline environments  

Microsoft Academic Search

Acetate uptake and turnover rates were determined for the heterotrophic community in hypersaline environments (saltern crystallizer ponds, the Dead Sea) dominated by halpphilic Archaea. Acetate was formed from glycerol, which is potentially the major available carbon source for natural communities of halophilic Archaea. Values of [Kt + Sn] (the sum of the substrate affinity and the substrate concentration present in

Aharon Oren

1995-01-01

417

Characterization of acetic acid bacteria in “traditional balsamic vinegar”  

Microsoft Academic Search

This study evaluated the glucose tolerance of acetic acid bacteria strains isolated from Traditional Balsamic Vinegar. The results showed that the greatest hurdle to acetic acid bacteria growth is the high sugar concentration, since the majority of the isolated strains are inhibited by 25% of glucose. Sugar tolerance is an important technological trait because Traditional Balsamic Vinegar is made with

Maria Gullo; Cinzia Caggia; Luciana De Vero; Paolo Giudici

2006-01-01

418

Cellulose production by acetic acid-resistant Acetobacter xylinum  

Microsoft Academic Search

A bacterium that could produce a gelatinous cellulosic pellicle in the presence of more than 2% acetic acid was isolated as a contaminant in a continuous surface culture for acetic acid production using Acetobacter aceti. The bacterium was identified as a strain belonging to Acetobacter xylinum and designated as strain DA. The production of cellulose in a static culture of

Kiyoshi Toda; Tomoko Asakura; Masahiro Fukaya; Etsuzo Entani; Yoshiya Kawamura

1997-01-01

419

Transition-Metal-Catalyzed Carbonylation of Methyl Acetate.  

ERIC Educational Resources Information Center

Presents a study of the rhodium-catalyzed, ioding-promoted carbonylation of methyl acetate. This study provides an interesting contrast between the carbonylation of methyl acetate and the carbonylation of methanol when similar rhodium/iodine catalyst systems are used. (JN)

Polichnowski, S. W.

1986-01-01

420

Priming of human monocyte superoxide production and arachidonic acid metabolism by adherence to collagen- and basement membrane-coated surfaces  

Microsoft Academic Search

Monocytes (ms) come into intimate contact with basement membranes and extracellular matrix pro- teins as they extravasate from the blood to the inter- stitium or to sites of tissue injury. We examined the in vitro effects of madherence to an endothelial cell-der- ived basement membrane or to purified extracellular matrix proteins on phorbol myristate acetate (PMA)-stimulated superoxide production and prostanoid

Paul W. Gudewicz; Mary Beth Frewin; Lynn A. Heinel; Fred L. Minnear

1994-01-01

421

Anion permselective membrane  

NASA Technical Reports Server (NTRS)

The efforts on the synthesis of polymer anion redox membranes were mainly concentrated in two areas, membrane development and membrane fabrication. Membrane development covered the preparation and evaluation of experimental membranes systems with improved resistance stability and/or lower permeability. Membrane fabrication covered the laboratory scale production of prime candidate membranes in quantities of up to two hundred and sizes up to 18 inches x 18 inches (46 cm x 46 cm). These small (10 in x 11 in) and medium sized membranes were mainly for assembly into multicell units. Improvements in processing procedures and techniques for preparing such membrane sets lifted yields to over 90 percent.

Hodgdon, R. B.; Waite, W. A.

1980-01-01

422

Acetate addition to an immobilized yeast column for ethanol production  

SciTech Connect

Acetate, a by-product of ethanol fermentation by Saccharomyces cerevisiae, has been shown to inhibit cell growth if present in high concentrations. Consequently, acetate has been considered undesirable in systems where the production rate depends upon steady-state growth. Acetate, however, may be desirable in some systems since it increases the specific rate of ethanol production by increasing the maintenance requirements of the yeast. In immobilized cell reactors using crosslinking method, steady state is not achieved and cell overgrowth is a problem. This article presents the results of a study aimed at taking advantage of the use of acetate, both to reduce cell overgrowth and increase productivity. Various concentrations of acetate were added to batch and plug flow systems, while monitoring the effects on cell growth and ethanol production. The productivity was increased by as much as 50% in an immobilized cell reactor (ICR), while cell growth was greatly reduced. 19 references.

Vega, J.L.; Clausen, E.C.; Gaddy, J.L.

1987-03-01

423

Glycerol acetals as anti-freezing additives for biodiesel.  

PubMed

Glycerol acetals from butanal, pentanal, hexanal, octanal and decanal were prepared with the use of Amberlyst-15 acid resin as catalyst. The glycerol conversion decreases with the size of the hydrocarbon chain. This fact has been associated with formation of micelles and aggregates of the aldehyde to minimize the interaction between the polar glycerol molecule with the hydrocarbon chain. The Z+E mixture of the acetals with five and six-member rings were produced in all cases. The distribution of the acetal isomers varied with the reaction time, especially for the long chain aldehydes. Addition of 5 vol.% of the butanal-glycerol acetal reduced the pour point of animal fat biodiesel (methyl ester) from 18 to 13 degrees C. The decrease in the pour point of the glycerol acetals-biodiesel mixtures were dependent on the size of the hydrocarbon chain and the percent blended. PMID:20304633

Silva, Paulo H R; Gonçalves, Valter L C; Mota, Claudio J A

2010-08-01

424

Synthesis of basement membrane collagen by cultured human endothelial cells  

PubMed Central

Studies were performed to determine if cultured human endothelial cells synthesized basement membrane collagen. In culture, endothelial cells were attached to grossly visible membranous structures which on light microscopy were composed of ribbons of dense, amorphous material. On transmission electron microscopy, these membranous structures consisted of amorphous basement membrane, and material morphologically similar to microfibrils and elastic fibers. By immunofluorescence microscopy, these membranous structures stained brightly with antisera to human glomerular basement membrane. Cultured endothelial cells incorporated [3H]proline into protein; 18% of the incorporated [3H]proline was solubilized by purified collagenase. When endothelial cells were cultured with [14C]proline, 7.1% of the incorporated counts were present as [14C]hydroxyproline. Cultured endothelial cells were labeled with [3H]glycine and [3H]proline and digested with pepsin. The resulting fractions on analysis by SDS-polyacrylamide gel electrophoresis contained two radioactive protein peaks of mol wt 94,200 and 120,500. Both these peaks disappeared after digestion with purified collagenase. The peak of mol wt 120,500 corresponds to that of alpha1 (IV) collagen; the peak of the mol wt 94,200 probably corresponds to that of alpha1 (III) collagen. Thus, cultured human endothelial cells synthesize material which is morphologically and immunologically like amorphous basement membrane and biochemically like basement membrane collagen. Cultured endothelial cells probably also synthesize material which is morphologically similar to microfibrils and elastic fibers. PMID:58957

1976-01-01

425

New insights in carbohydrate-deficient transferrin analysis with capillary electrophoresis-mass spectrometry.  

PubMed

Capillary zone electrophoresis (CZE) with UV detection has been widely used for the determination of carbohydrate-deficient transferrin (CDT), an indirect marker of the chronic alcohol consumption (?60-80g/day). A commercially available method (CEofix™ CDT kit), containing a bilayer anionic coating, allows for the analysis of CDT with a high resolution between transferrin (Tf) glycoforms with reduced protein adsorption onto the capillary wall. Although widely used in routine analysis, this procedure presents some limitations in terms of selectivity and sensitivity which may be overcome with mass spectrometry (MS). However, the available method is not MS-compatible due to the non-volatile coating as well as the phosphate and borate buffers present in the background electrolyte (BGE). This study firstly consisted in developing MS-compatible separation conditions, i.e., coating and BGE compositions. Numerous cationic, neutral, and anionic coatings were evaluated in combination with BGEs covering a broad range of pH values. A bilayer coating composed of a cationic layer of 10% polybrene (m/v) and an anionic layer of 10% dextran sulfate (m/v) combined with a BGE composed of 20mM ammonium acetate at pH 8.5 provided the best results in terms of glycoforms' resolution, efficiency, adsorption reduction, migration times' repeatability, and coating stability. The method was then transferred to CZE-MS after investigations of the electrospray ionization (ESI) source, equipped with a sheath-flow interface, and the time-of-flight (TOF/MS) parameters. A successful MS detection of tetrasialo-Tf was obtained during infusion, while the experiments highlighted the challenges and issues encountered with intact glycoprotein analysis by CZE-ESI-MS. PMID:24763189

Kohler, Isabelle; Augsburger, Marc; Rudaz, Serge; Schappler, Julie

2014-10-01

426

Drug impurity profiling by capillary electrophoresis/mass spectrometry using various ionization techniques.  

PubMed

Capillary electrophoresis/mass spectrometry (CE/MS) is predominantly carried out using electrospray ionization (ESI). Recently, atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) have become available for CE/MS. With the VUV lamp turned off, the APPI source may also be used for CE/MS by thermospray ionization (TSI). In the present study the suitability of ESI, APCI, APPI and TSI for drug impurity profiling by CE/MS in the positive ion mode is evaluated. The drugs carbachol, lidocaine and proguanil and their potential impurities were used as test compounds, representing different molecular polarities. A background electrolyte of 100 mM acetic acid (pH 4.5) provided baseline separation of nearly all impurities from the respective drugs. APPI yielded both even- and odd-electron ions, whereas the other ionization techniques produced even-electron ions only. In-source fragmentation was more pronounced with APCI and APPI than with ESI and TSI, which was most obvious for proguanil and its impurities. In general, ESI and TSI appeared the most efficient ionization techniques for impurities that are charged in solution achieving detection limits of 100 ng/mL (full-scan mode). APPI and APCI showed a lower efficiency, but allowed ionization of low and high polarity analytes, although quaternary ammonium compounds (e.g. carbachol) could not be detected. Largely neutral compounds, such as the lidocaine impurity 2,6-dimethylaniline, could not be detected by TSI, and yielded similar detection limits (500 ng/mL) for ESI, APPI and APCI. In many cases, impurity detection at the 0.1% (w/w) level was possible when 1 mg/mL of parent drug was injected with at least one of the CE/MS systems. Overall, the tested CE/MS systems provide complementary information as illustrated by the detection and identification of an unknown impurity in carbachol. PMID:19670338

Hommerson, Paul; Khan, Amjad M; Bristow, Tony; Harrison, Mark W; de Jong, Gerhardus J; Somsen, Govert W

2009-09-01

427

Analysis of hemoglobin electrophoresis results and physicians investigative practices in Saudi Arabia  

PubMed Central

BACKGROUND AND OBJECTIVES: Riyadh and central province falls in a moderate prevalent zone of hemoglobinopathies in Saudi Arabia. However, it has been observed that the physicians working in Saudi Arabia invariably advise all cases of anemia for hemoglobin electrophoresis (HE). The present work was carried out to study the yield of the HE in Riyadh and the investigative practices of the physicians advising HE. SETTINGS AND DESIGN: The study was carried out in the hospitals of King Saud University from 2009 to 2011 in order to assess the yield of HE in referred cases of clinical anemia. MATERIALS AND METHODS: A total of 1073 cases divided in two groups of males and females had undergone complete blood count and red blood cell morphology. Cellulose acetate HE was performed and all the positive results were reconfirmed on the high performance liquid chromatography (HPLC). The results were analyzed for the type of hemoglobinopathies. For statistical analysis Statistical Package for Social Sciences 15 version (SPSS Inc., Chicago, IL, USA) was used. RESULTS: A total of 405 males and 668 females blood samples were included in the present study. 116 (28.5%) males and 167 (25%) females showed an abnormal pattern on HE. The incidence of beta thalassemia trait was higher in females while sickle cell trait was predominantly seen in males. Red cell indices were reduced considerably in thalassemias, but were unaffected in sickle cell disorders, except those which had concurrent alpha trait. The total yield of HE was 26.6% which was much less than expected. CONCLUSION: The physicians are advised to rule out iron deficiency and other common causes of anemia before investigating the cases for hemoglobinopathies, which employs time consuming and expensive tests of HE and HPLC. PMID:24339548

Mehdi, Syed Riaz; Al Dahmash, Badr Abdullah

2013-01-01

428

Polyvinyl acetate-based film coatings.  

PubMed

Polyvinyl acetate-based colloidal aqueous polymer dispersion Kollicoat(®) SR 30 D results in coatings characterized by moderate swelling behaviour, lipophilicity, pH-independent permeability for actives and high flexibility to withstand mechanical stress and is therefore used for controlled release coating. The colloidal aqueous polymer dispersion of Kollicoat(®) SR 30 D can be easily processed due to an optimal low minimum film forming temperature (MFT) of 18 °C without plasticizer addition and a thermal after-treatment (curing) of coated pellets. The drug release from Kollicoat(®) SR 30 D coated pellets was almost pH independent. Drug release could be easily adjusted by coating level or addition of soluble pore forming polymers. Physically stable Kollicoat(®) SR 30 D dispersions were obtained with the water-soluble polymers Kollidon(®) 30 and Kollicoat(®) IR up to 50% w/w. The addition of only 10% w/w triethyl citrate as plasticizer improved the flexibility of the films significantly and allowed compaction of the pellets. The drug release was almost independent of the compression force and the pellet content of the tablets. The inclusion of various tableting excipients slightly affected the drug release, primarily because of a different disintegration rate of the tablets. A combination of Kollicoat(®) SR 30 D and Kollicoat(®) IR with higher coating levels>10 mg/cm(2) is a relatively new alternative to OROS system which does not require drilling. PMID:24076229

Kolter, K; Dashevsky, A; Irfan, Muhamad; Bodmeier, R

2013-12-01

429

Synthesis and properties of cyclic acetal biomaterials.  

PubMed

There is an increasing need to develop new biomaterials as tissue engineering scaffolds. Unfortunately, many of the materials that have been studied for these purposes are polyesters that hydrolytically degrade into acidic products, which may harm the surrounding tissue, and lead to accelerated degradation of the biomaterial. To overcome this disadvantage, a novel class of biomaterials based on a cyclic acetal unit has been created. Specifically, materials based upon the monomer 5-ethyl-5-(hydroxymethyl)-beta,beta-dimethyl-1,3-dioxane-2-ethanol diacrylate (EHD) is examined. This study investigates the effects of fabrication parameters, including initiator content, volume of diluent, and volume of accelerant, on several properties of EHD networks. Twelve different formulations were fabricated by varying the three parameters in a factorial design. The effects of the fabrication parameters on properties of the EHD networks were examined. Results show that the volume of accelerant most affected the EHD network gelation time, while the volume of diluent most affected the maximum reaction temperature, sol fraction, and degree of swelling. Cell viability on the EHD networks varied between (18 +/- 6)% and (57 +/- 10)% of the control at 4 h, and between (36 +/- 14)% and (140 +/- 50)% of the control at 8 h. These results indicate that it is possible to control the properties of the EHD networks by varying the fabrication parameters, and that EHD networks support a viable cell population. PMID:17177269

Moreau, Jennifer L; Kesselman, Dafna; Fisher, John P

2007-06-01

430

Pharmacokinetics and drug interactions of eslicarbazepine acetate.  

PubMed

Eslicarbazepine acetate (ESL) is a novel once-daily antiepileptic drug (AED) approved in Europe since 2009 that was found to be efficacious and well tolerated in a phase III clinical program in adult patients with partial onset seizures previously not controlled with treatment with one to three AEDs, including carbamazepine (CBZ). ESL shares with CBZ and oxcarbazepine (OXC) the dibenzazepine nucleus bearing the 5-carboxamide substitute, but is structurally different at the 10,11 position. This molecular variation results in differences in metabolism, preventing the formation of toxic epoxide metabolites such as carbamazepine-10,11-epoxide. Unlike OXC, which is metabolized to both eslicarbazepine and (R)-licarbazepine, ESL is extensively converted to eslicarbazepine. The systemic exposure to eslicarbazepine after ESL oral administration is approximately 94% of the parent dose, with minimal exposure to (R)-licarbazepine and OXC. After ESL oral administration, the effective half-life (t(1/2,eff) ) of eslicarbazepine was 20-24 h, which is approximately two times longer than its terminal half-life (t(1/2)). At clinically relevant doses (400-1,600 mg/day) ESL has linear pharmacokinetics (PK) with no effects of gender or moderate liver impairment. However, because eslicarbazepine is eliminated primarily (66%) by renal excretion, dose adjustment is recommended for patients with renal impairment. Eslicarbazepine clearance is induced by phenobarbital, phenytoin, and CBZ and it dose-dependently decreases plasma exposure of oral contraceptive and simvastatin. PMID:22612290

Bialer, Meir; Soares-da-Silva, Patricio

2012-06-01

431

UVB photolysis of hydrocortisone 21-acetate.  

PubMed

Hydrocortisone 21-acetate (HCA) in methanol solution undergoes photodegradation under UVB light, as monitored by HPLC. Five main photoproducts have been isolated and characterized by means of NMR and mass spectroscopy. One of them derives from a Norrish I photoreaction which cleaves the C17-C20 bond of the steroid yielding the andro-derivative, a second product comes from a Yang-type photorearrangement which links C18 to C20 yielding a cyclobutane adduct. The former photoproduct, in turn, undergoes further photolysis giving rise to various photoproducts, of which three have been characterized. The first is a stereoisomer of the andro-derivative, the others arise from the opening of the five-membered ring. HCA also proved photounstable in the solid state and in a commercial formulation for topical use, thus confirming the requirements of the Pharmacopeias for light protection of this drug. Indeed, experiments on LPS-stimulated THP-1 cells demonstrated the loss of anti-inflammatory activity when HCA was UVB-photodegraded. The radical mechanism involved in HCA photolysis seems also responsible for the in vitro photohemolytic effect and lipid peroxidation induced by HCA in combination with UVB light. PMID:18423938

Caffieri, Sergio; Dall'Acqua, Stefano; Castagliuolo, Ignazio; Brun, Paola; Miolo, Giorgia

2008-08-01

432

Graphene/poly(ethylene-co-vinyl acetate) composite electrode fabricated by melt compounding for capillary electrophoretic determination of flavones in Cacumen platycladi.  

PubMed

In this report, a graphene/poly(ethylene-co-vinyl acetate) composite electrode was fabricated by melt compounding for the amperometric detection of capillary electrophoresis. The composite electrode was fabricated by packing a mixture of graphene and melted poly(ethylene-co-vinyl acetate) in a piece of fused silica capillary under heat. The structure of the composite was investigated by scanning electron microscopy and Fourier transform infrared spectroscopy. The results indicated that graphene sheets were well dispersed in the composite to form an interconnected conducting network. The performance of this unique graphene-based detector has been demonstrated by separating and detecting rutin, quercitrin, kaempferol, and quercetin in Cacumen platycladi in combination with capillary electrophoresis. The four flavones have been well separated within 9 min in a 50-cm-long capillary at a separation voltage of 12 kV using a 50 mM sodium borate buffer (pH 9.2). The graphene-based detector offered significantly lower operating potentials, substantially enhanced signal-to-noise characteristics, lower expense of operation, high resistance to surface fouling, and enhanced stability. It showed long-term stability and repeatability with relative standard deviations of <5% for the peak current (n = 15). PMID:23355382

Sheng, Shijun; Liu, Shuang; Zhang, Luyan; Chen, Gang

2013-02-01

433

Effects of chronic and acute lead treatments on the biophysical properties of erythrocyte membranes, and a comparison with model membranes?  

PubMed Central

Rat erythrocytes, or erythrocyte membrane ghosts, have been subjected to either chronic (drinking water containing 15?mM lead acetate for 3?months) or acute (10?9–10?2?M lead acetate for 1?h) Pb2+ treatments and subsequent changes in membrane properties have been measured. Pb2+ concentration in chronically treated rat plasma was 1.8??M, which is one order of magnitude above normal values. Membrane permeability, or hemolysis, was increased in both cases. A comparative study using liposomes, in the form of large unilamellar vesicles, also indicated an increase in membrane permeability. Membrane microviscosity, or acyl chain molecular order, measured as DPH fluorescence polarization, showed an increased order in the acute treatments, at least below 700??M Pb2+, and a similar increase in chronically treated rats. The correlation between acute and chronic treatments, and between cell and model membranes, suggests that the present observations may be relevant in the pathogenesis of lead intoxication in humans. PMID:23772396

Ahyayauch, Hasna; Sansar, Wafae; Rendón-Ramírez, Adela; Goñi, Félix M.; Bennouna, Mohammed; Gamrani, Halima

2013-01-01

434

Improving the Expression of Recombinant Proteins in E. coli BL21 (DE3) under Acetate Stress: An Alkaline pH Shift Approach  

PubMed Central

Excess acetate has long been an issue for the production of recombinant proteins in E. coli cells. Recently, improvements in acetate tolerance have been achieved through the use of genetic strategies and medium supplementation with certain amino acids and pyrimidines. The aim of our study was to evaluate an alternative to improve the acetate tolerance of E. coli BL21 (DE3), a popular strain used to express recombinant proteins. In this work we reported the cultivation of BL21 (DE3) in complex media containing acetate at high concentrations. In the presence of 300 mM acetate, compared with pH 6.5, pH 7.5 improved cell growth by approximately 71%, reduced intracellular acetate by approximately 50%, and restored the expression of glutathione S-transferase (GST), green fluorescent protein (GFP) and cytochrome P450 monooxygenase (CYP). Further experiments showed that alkaline pHs up to 8.5 had little inhibition in the expression of GST, GFP and CYP. In addition, the detrimental effect of acetate on the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) by the cell membrane, an index of cellular metabolic capacity, was substantially alleviated by a shift to alkaline pH values of 7.5–8.0. Thus, we suggest an approach of cultivating E. coli BL21 (DE3) at pH 8.0±0.5 to minimize the effects caused by acetate stress. The proposed strategy of an alkaline pH shift is a simple approach to solving similar bioprocessing problems in the production of biofuels and biochemicals from sugars. PMID:25402470

Wang, Hengwei; Wang, Fengqing; Wang, Wei; Yao, Xueling; Wei, Dongzhi; Cheng, Hairong; Deng, Zixin

2014-01-01

435

Continuous flow electrophoresis: The effect of sample concentration on throughput and resolution in an upward flowing system  

NASA Technical Reports Server (NTRS)

The effect of sample concentration on throughput and resolution in a modified continuous particle electrophoresis (CPE) system with flow in an upward direction is investigated. Maximum resolution is achieved at concentrations ranging from 2 x 10 to the 8th power cells/ml to 8 x 10 to the 8th power cells/ml. The widest peak separation is at 2 x 10 to the 8th power cells/ml; however, the sharpest peaks and least overlap between cell populations is at 8 x 10 to the 8th power cells/ml. Apparently as a result of improved electrophoresis cell performance due to coasting the chamber with bovine serum albumin, changing the electrode membranes and rinse, and lowering buffer temperatures, sedimentation effects attending to higher concentrations are diminished. Throughput as measured by recovery of fixed cells is diminished at the concentrations judged most likely to yield satisfactory resolution. The tradeoff appears to be improved recovery/throughput at the expense of resolution.

Jandebeur, T. S.

1980-01-01

436

Hereditary red cell membrane disorders and laboratory diagnostic testing.  

PubMed

This overview describes two groups of nonimmune hereditary hemolytic anemias caused by defects in membrane proteins located in distinct layers of the red cell membrane. Hereditary spherocytosis (HS), hereditary elliptocytosis (HE), and hereditary pyropoikilocytosis (HPP) represent disorders of the red cell cytoskeleton. Hereditary stomatocytoses represents disorders of cation permeability in the red cell membrane. The current laboratory screening tests for HS are the osmotic fragility test, acid glycerol lysis time test (AGLT), cryohemolysis test, and eosin-5'-maleimide (EMA)-binding test. For atypical HS, SDS-polyacrylamide gel electrophoresis of erythrocyte membrane proteins is carried out to confirm the diagnosis. The diagnosis of HE/HPP is based on abnormal red cell morphology and the detection of protein 4.1R deficiency or spectrin variants using gel electrophoresis. None of screening tests can detect all HS cases. Some testing centers (a survey of 25 laboratories) use a combination of tests (e.g., AGLT and EMA). No specific screening test for hereditary stomatocytoses is available. The preliminary diagnosis is based on presenting a compensated hemolytic anemia, macrocytosis, and a temperature or time dependent pseudohyperkalemia in some patients. Both the EMA-binding test and the osmotic fragility test may help in differential diagnosis of HS and hereditary stomatocytosis. PMID:23480868

King, M-J; Zanella, A

2013-06-01

437

Standardization of DNA extraction from methanol acetic acid fixed cytogenetic cells of cattle and buffalo.  

PubMed

The aim of the study is to standardize the simple method for extracting DNA from cells fixed in fixative (3:1 ratio of methanol and acetic acid glacial) mostly used for chromosomal studies in cattle and buffaloes. These fixed cells were stored for more than 6 months at refrigerated temperature. The fixed cells were washed 2-3 times by the ice cold 1x Phosphate Buffer Saline (PBS) with pH 7.4, so that effect of fixative may be eliminated. The genomic DNA was extracted by adding cell lysis and nucleus lysis buffers. The quality and quantity of DNA were estimated. The readings of nano drop and agarose gel electrophoresis indicate good quality DNA isolated with a rapid and simple protocol routinely using in our laboratory. The method enables us to study the DNA of a cattle and buffaloes after completing cytogenetic investigation or in cases where DNA samples are otherwise not available. This protocol may be useful for molecular analysis of DNA from fixed cells palettes. PMID:24506057

Kotikalapudi, Rosaiah; Patel, Rajesh K; Katragadda, Sanghamitra

2013-12-01

438

Genetic variability among Chlamydia trachomatis reference and clinical strains analyzed by pulsed-field gel electrophoresis.  

PubMed

Pulsed-field gel electrophoresis (PFGE) was applied to Chlamydia trachomatis reference strains representing each of the 18 serovars and to 29 clinical isolates from genital specimens collected in Bordeaux, France, or Malmö, Sweden. Comparison of the fingerprint patterns of the reference strains revealed a high level of polymorphism of the total DNA when SmaI was used (14 profiles), whereas the other enzymes, Sse8387I and ApaI, showed fewer differences. Some serovars, considered to be closely related on the basis of their antigenic determinants located on the major outer membrane protein (MOMP), such as D and Da or I and Ia, were shown to be different after PFGE of their genomic DNAs. However, serovars B and Ba and serovars L2 and L2a had identical patterns after analysis with the three endonucleases. When applied to clinical isolates, which were typed by restriction fragment length polymorphism analysis of the MOMP gene, PFGE allowed the detection of intragenotype polymorphisms and showed the identity of two strains successively isolated from the same patient. This technique seems to be an efficient tool for epidemiological studies when used in addition to serotyping or genotyping by restriction fragment length polymorphism analysis of the MOMP gene. PMID:7883878

Rodriguez, P; Allardet-Servent, A; de Barbeyrac, B; Ramuz, M; Bebear, C

1994-12-01

439

Integrated allele-specific polymerase chain reaction-capillary electrophoresis microdevice for single nucleotide polymorphism genotyping.  

PubMed

An integrated allele-specific (AS) polymerase chain reaction (PCR) and capillary electrophoresis (CE) microdevice has been developed for multiplex single nucleotide polymorphism (SNP) genotyping on a portable instrumentation, which was applied for on-site identification of HANWOO (Korean indigenous beef cattle). Twelve sets of primers were designed for targeting beef cattle's eleven SNP loci for HANWOO verification and one primer set for a positive PCR control, and the success rate for identification of HANWOO was demonstrated statistically. The AS PCR and CE separation for multiplex SNP typing was carried out on a glass-based microchip consisting of four layers: a microchannel plate for microfluidic control, a Pt-electrode plate for a resistance temperature detector (RTD), a poly(dimethylsiloxane) (PDMS) membrane and a manifold glass for microvalve function. The operation of the sample loading, AS PCR, microvalve, and CE on a chip was automated with a portable genetic analyzer, and the laser-induced fluorescence detection was performed on a miniaturized fluorescence detector. The blind samples were correctly identified as a HANWOO by showing one or two amplicon peaks in the electropherogram, while the imported beef cattle revealed more than five peaks. Our genetic analysis platform provides rapid, accurate, and on-site multiplex SNP typing. PMID:22464916

Choi, Jong Young; Kim, Yong Tae; Ahn, Jinwoo; Kim, Kwan Suk; Gweon, Dae-Gab; Seo, Tae Seok

2012-05-15

440

Development of a Simplified Microfluidic Injector for Analysis of Droplet Content via Capillary Electrophoresis.  

PubMed

Droplet-based microfluidic platforms sequester nanoliter to picoliter samples in an immiscible carrier phase and have gained notoriety for their ability to be used in laboratory procedures on a miniaturized scale. Recently, droplet microfluidics has been used to prevent zone diffusion in time-resolved sample collection methods and in separation techniques. The assay of droplets remains challenging, however, because the carrier phase is often incompatible with separation techniques. In this work, we report the development of a droplet injector for capillary electrophoresis (CE) which delivers 750 pL droplets to a channel for separation while excluding the fluorous carrier phase. This design is simple compared to previous reports, consisting of only two straight channels and no additional working parts such as membranes or valves. To demonstrate a proof-of-concept and characterize performance, riboflavin was used as a biologically relevant model molecule. Droplets containing a step change in riboflavin concentration were injected and mobilized by CE. The current method is capable of riboflavin peak % relative standard deviations (RSDs) down to 4.4% and temporal resolutions down to 15 s. Human urine samples containing riboflavin and its photolysis products were successfully separated and found to be chemically compatible with the injector. Our simplified design could improve robustness and ruggedness and may allow device construction via nontraditional fabrication techniques. PMID:25226066

DeLaMarre, Michael F; Shippy, Scott A

2014-10-21

441

76 FR 32366 - Determination That ORLAAM (Levomethadyl Acetate Hydrochloride) Oral Solution, 10 Milligrams...  

Federal Register 2010, 2011, 2012, 2013

...Levomethadyl Acetate Hydrochloride) Oral Solution, 10 Milligrams/Milliliter, Was Not...acetate hydrochloride (HCl)) oral solution, 10 milligrams (mg)/milliliter...ANDAs) for levomethadyl acetate HCl oral solution, 10 mg/mL, if all other legal...

2011-06-06

442

Water dispersible microbicidal cellulose acetate phthalate film  

PubMed Central

Background Cellulose acetate phthalate (CAP) has been used for several decades in the pharmaceutical industry for enteric film coating of oral tablets and capsules. Micronized CAP, available commercially as "Aquateric" and containing additional ingredients required for micronization, used for tablet coating from water dispersions, was shown to adsorb and inactivate the human immunodeficiency virus (HIV-1), herpesviruses (HSV) and other sexually transmitted disease (STD) pathogens. Earlier studies indicate that a gel formulation of micronized CAP has a potential as a topical microbicide for prevention of STDs including the acquired immunodeficiency syndrome (AIDS). The objective of endeavors described here was to develop a water dispersible CAP film amenable to inexpensive industrial mass production. Methods CAP and hydroxypropyl cellulose (HPC) were dissolved in different organic solvent mixtures, poured into dishes, and the solvents evaporated. Graded quantities of a resulting selected film were mixed for 5 min at 37°C with HIV-1, HSV and other STD pathogens, respectively. Residual infectivity of the treated viruses and bacteria was determined. Results The prerequisites for producing CAP films which are soft, flexible and dispersible in water, resulting in smooth gels, are combining CAP with HPC (other cellulose derivatives are unsuitable), and casting from organic solvent mixtures containing ?50 to ?65% ethanol (EtOH). The films are ?100 µ thick and have a textured surface with alternating protrusions and depressions revealed by scanning electron microscopy. The films, before complete conversion into a gel, rapidly inactivated HIV-1 and HSV and reduced the infectivity of non-viral STD pathogens >1,000-fold. Conclusions Soft pliable CAP-HPC composite films can be generated by casting from organic solvent mixtures containing EtOH. The films rapidly reduce the infectivity of several STD pathogens, including HIV-1. They are converted into gels and thus do not have to be removed following application and use. In addition to their potential as topical microbicides, the films have promise for mucosal delivery of pharmaceuticals other than CAP. PMID:14617380

Neurath, A Robert; Strick, Nathan; Li, Yun-Yao

2003-01-01

443

Analysis of protein glycation using fluorescent phenylboronate gel electrophoresis  

PubMed Central

Glycated proteins are important biomarkers for age-related disorders, however their analysis is challenging because of the complexity of the protein-carbohydrate adducts. Here we report a method that enables the detection and identification of individual glycated proteins in complex samples using fluorescent boronic acids in gel electrophoresis. Using this method we identified glycated proteins in human serum, insect hemolymph and mouse brain homogenates, confirming this technique as a powerful proteomics tool that can be used for the identification of potential disease biomarkers. PMID:23531746

Pereira Morais, Marta P.; Marshall, Dominic; Flower, Stephen E.; Caunt, Christopher J.; James, Tony D.; Williams, Robert J.; Waterfield, Nicholas R.; van den Elsen, Jean M. H.

2013-01-01

444

Capillary electrophoresis: Biotechnology for separation of DNA and chromosomes  

NASA Technical Reports Server (NTRS)

Electrophoresis has been used for the separation of particles, ions, and molecules for a number of years. The technology for separation and detection of the results has many applications in the life sciences. One of the major goals of the scientific community is to separate DNA molecules and intact chromosomes based upon their different lengths or number of base pairs. This may be achieved by using some of the commercially available and widely used methods, but these processes require a considerable amount of time. The challenge is to achieve separation of intact chromosomes in a short time, preferably in a matter of minutes.

Williams, George O., Jr.

1994-01-01

445

FRACTIONATION OF SPINACH CHLOROPLASTS BY FLOW SEDIMENTATION-ELECTROPHORESIS  

E-print Network

A separation of spinach chloroplasts in vitro into fractions according to size (volume) and activity (light-dependent shrinkage and NADP reduction) has been achieved by stableflow free boundary sedimentation-electrophoresis. The salient features of this chloroplast study are: (a) separation is achieved within 30 min; (b) only small density gradients are required, thus minimizing osmotic effects; (c) the fractions are collected continuously, with size fractionation being evidenced; and (d) particles are separated into fractions of higher and lower activities as compared with the control population.

Lester Packer; Park S. Nobel; Elizabeth L. Gross; Howard C. Mel

446

Capillary electrophoresis-electrochemical detection microchip device and supporting circuits  

DOEpatents

The present invention is a capillary electrophoresis device, comprising a substrate; a first channel in the substrate, and having a buffer arm and a detection arm; a second channel in the substrate intersecting the first channel, and having a sample arm and a waste arm; a buffer reservoir in fluid communication with the buffer arm; a waste reservoir in fluid communication with the waste arm; a sample reservoir in fluid communication with the sample arm; and a detection reservoir in fluid communication with the detection arm. The detection arm and the buffer arm are of substantially equal length.

Jackson, Douglas J. (New Albany, IN); Roussel, Jr., Thomas J. (Louisville, KY); Crain, Mark M. (Georgetown, IN); Baldwin, Richard P. (Louisville, KY); Keynton, Robert S. (Louisville, KY); Naber, John F. (Prospect, KY); Walsh, Kevin M. (Louisville, KY); Edelen, John. G. (Versailles, KY)

2008-03-18

447

Electronic imaging systems for quantitative electrophoresis of DNA  

SciTech Connect

Gel electrophoresis is one of the most powerful and widely used methods for the separation of DNA. During the last decade, instruments have been developed that accurately quantitate in digital form the distribution of materials in a gel or on a blot prepared from a gel. In this paper, I review the various physical properties that can be used to quantitate the distribution of DNA on gels or blots and the instrumentation that has been developed to perform these tasks. The emphasis here is on DNA, but much of what is said also applies to RNA, proteins and other molecules. 36 refs.

Sutherland, J.C.

1989-01-01

448

Analysis of anions in drinking water by capillary ion electrophoresis.  

PubMed

Capillary ion electrophoresis (CIE) (Waters' trade name: Capillary Ion Analysis, CIA) is a capillary electrophoretic technique which is optimized for the rapid analysis of low-molecular-mass inorganic and organic ions. An electroosmotic flow modifier (OFM) was added to the chromate electrolyte and a negative power supply was used. Indirect UV detection at 254 nm was used throughout. Analysis of anions in a variety of drinking water samples was done. Anion analysis using this technique is rapid (less than 5.5 min), with little sample preparation required. Comparison of anion amounts found using CIA and conventional suppressed ion chromatography (IC) was done with good correlation between the two techniques. PMID:8814788

Oehrle, S A

1996-05-10

449

The application of capillary electrophoresis techniques in toxicological analysis.  

PubMed

Capillary electrophoresis (CE) comprises a group of techniques used to separate chemical mixtures. Analytical separation is based on different electrophoretic mobilities, thereby allowing qualitative and quantitative evaluations to be made. The application of CE in medical science, especially in toxicological studies, is developing rapidly because of the short time required for analysis and its high sensitivity, selectivity and ability to determine substances of an acidic, alkaline and neutral character. This review focuses on the possibility of applying CE in toxicological analysis. Advances in different CE analyses and detection techniques connected with this method are described. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24828301

Sieradzka, Ewelina; Witt, Katarzyna; Milnerowicz, Halina

2014-11-01

450

Separation of long RNA by agarose-formaldehyde gel electrophoresis.  

PubMed

We describe a method to facilitate electrophoretic separation of high-molecular-weight RNA species, such as ribosomal RNAs and their precursors, on agarose-formaldehyde gels. Two alternative "pK-matched" buffer systems were substituted for the traditionally used Mops-based conductive medium. The key advantages include shortened run times, a 5-fold reduction in formaldehyde concentration, a significantly improved resolution of long RNAs, and consistency in separation. The new procedure has a streamlined work flow that helps to minimize errors and is broadly applicable to agarose gel electrophoresis of RNA samples and their subsequent analysis by Northern blotting. PMID:23800830

Mansour, Farrah H; Pestov, Dimitri G

2013-10-01

451

Separation of long RNA by agarose-formaldehyde gel electrophoresis  

PubMed Central

We describe a method to facilitate electrophoretic separation of high molecular weight RNA species, such as ribosomal RNAs and their precursors, on agarose-formaldehyde gels. Two alternative “pK-matched” buffer systems were substituted for the traditionally used MOPS-based conductive media. The key advantages include shortened run times, a five-fold reduction in formaldehyde concentration, a significantly improved resolution of long RNAs, and consistency in separation. The new procedure has a streamlined work flow that helps minimize errors and is broadly applicable to agarose gel electrophoresis of RNA samples and their subsequent analysis by Northern blotting. PMID:23800830

Mansour, Farrah H.; Pestov, Dimitri G.

2013-01-01

452

Basics and recent advances of two dimensional- polyacrylamide gel electrophoresis  

PubMed Central

Gel- based proteomics is one of the most versatile methods for fractionating protein complexes. Among these methods, two dimensional- polyacrylamide gel electrophoresis (2-DE) represents a mainstay orthogonal approach, which is popularly used to simultaneously fractionate, identify, and quantify proteins when coupled with mass spectrometric identification or other immunological tests. Although 2-DE was first introduced more than three decades ago, several challenges and limitations to its utility still exist. This review discusses the principles of 2-DE as well as both recent methodological advances and new applications. PMID:24735559

2014-01-01

453

Clostridiumm ljungdahlii, an anaerobic ethanol and acetate producing microorganism  

DOEpatents

A newly discovered microorganism was isolated in a biologically pure culture and designated Clostridium ljungdahlii, having the identifying characteristics of ATCC No. 49587. Cultured in an aqueous nutrient medium under anaerobic conditions, this microorganism is capable of producing ethanol and acetate from CO and H.sub.2 O and/or CO.sub.2 and H.sub.2 in synthesis gas. Under optimal growth conditions, the microorganism produces acetate in preference to ethanol. Conversely, under non-growth conditions, ethanol production is favored over acetate.

Gaddy, James L. (Fayetteville, AR); Clausen, Edgar C. (Fayetteville, AR)

1992-01-01

454

The medical and metabolic consequences of administration of sodium acetate.  

PubMed

1. The standard total parenteral nutrition, peritoneal dialysis, hemodialysis and many surgical fluids in use today contain 36 to 45 mM D,L-lactate or 2 to 140 mM acetate whereas the normal blood level of D-lactate is 0.02 mM L-lactate 0.5 to 5 mM and acetate 0.1 nM. The reasons for the continued use in patients of such unphysiological concentrations of these anions appear to be historic. 2. Administration of similar concentrations of these anions to the rat causes widespread metabolic disturbances which mimic many of the untoward complications associated with current parenteral and dialysis therapy. Understanding of the mechanisms attendant upon the metabolism of these anions may serve as a guide for designing improved parenteral fluids for human patients. 3. Elevation of blood D-lactate to 5 mM is associated with cerebral dysfunction in human patients. 4. Acetate stimulates the release of the inflammatory leukokine, interleukin-1 from human monocytes. Use of 35 to 45 mM acetate in peritoneal dialysis fluids led to peritoneal fibrosis. Patients exposed to acetate containing hemodialysis fluids have 12-fold elevation in their plasma interleukin-1 levels. 5. Administration of 20 mM sodium acetate to rats leads to a number of metabolic disturbances similar to those seen in human dialysis patients: (a) Acetate elevates blood glucose in the rat and may contribute to the exacerbation of the carbohydrate intolerance seen in uremic patients. (b) Acetate increases the levels of hepatic malonyl CoA, the rate controlling substrate of fatty acid synthesis and may exacerbate the hypertriglyceridemia characteristic of dialysis patients. (c) Acetate administration in the rat leads to a decrease in the cytosolic phosphorylation potential, reduction of the redox state of the free cytosolic NAD couple and paradoxical oxidation of the mitochondrial NAD couple in a pattern analogous to that produced by uncouplers of oxidative phosphorylation and may account in part for the elevation of temperature reported in patients undergoing hemodialysis with acetate. (d) Acetate administration in the rat leads to an increase in intracellular phosphorylated intermediates, adenine nucleotides, inorganic phosphate, inorganic pyrophosphate, calcium and magnesium. On cessation of acetate metabolism, the inorganic phosphate and calcium accumulated intracellularly leave the intracellular space. In patients undergoing hemodialysis, the blood phosphate returns to predialysis levels, within 6 hr after the completion of treatment, leaving significant numbers of patients with chronic hyperphosphatemia and the multiple complications attendant to that state.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2854950

Veech, R L; Gitomer, W L

1988-01-01

455

The antibacterial activity and stability of acetic acid.  

PubMed

Acetic acid has been shown to have good antibacterial activity against micro-organisms such as Pseudomonas aeruginosa. This study examined the activity against a range of bacterial pathogens and also assessed any reduction in antibacterial activity due to evaporation or inactivation by organic material in dressings. Acetic acid was active at dilutions as low as 0.166% and the activity was not reduced by evaporation nor by inactivation by cotton swabs. Burn injuries are a major problem in countries with limited resources. Acetic acid is an ideal candidate for use in patients who are treated in those parts of the world. PMID:23747099

Fraise, A P; Wilkinson, M A C; Bradley, C R; Oppenheim, B; Moiemen, N

2013-08-01

456

Change in microbial communities in acetate- and glucose-fed microbial fuel cells in the presence of light.  

PubMed

Power densities produced by microbial fuel cells (MFCs) in natural systems are changed by exposure to light through the enrichment of photosynthetic microorganisms. When MFCs with brush anodes were exposed to light (4000 lx), power densities increased by 8-10% for glucose-fed reactors, and 34% for acetate-fed reactors. Denaturing gradient gel electrophoresis (DGGE) profiles based on the 16S rRNA gene showed that exposure to high light levels changed the microbial communities on the anodes. Based on 16S rRNA gene clone libraries of light-exposed systems the anode communities using glucose were also significantly different than those fed acetate. Dominant bacteria that are known exoelectrogens were identified in the anode biofilm, including a purple nonsulfur (PNS) photosynthetic bacterium, Rhodopseudomonas palustris, and a dissimilatory iron-reducing bacterium, Geobacter sulfurreducens. Pure culture tests confirmed that PNS photosynthetic bacteria increased power production when exposed to high light intensities (4000 lx). These results demonstrate that power production and community composition are affected by light conditions as well as electron donors in single-chamber air-cathode MFCs. PMID:19574034

Xing, Defeng; Cheng, Shaoan; Regan, John M; Logan, Bruce E

2009-09-15

457

Application of culture culture-independent molecular biology based methods to evaluate acetic acid bacteria diversity during vinegar processing.  

PubMed

Acetic acid bacteria (AAB) are considered fastidious microorganisms because they are difficult to isolate and cultivate. Different molecular approaches were taken to detect AAB diversity, independently of their capacity to grow in culture media. Those methods were tested in samples that originated during traditional vinegar production. Bacterial diversity was assessed by analysis of 16S rRNA gene, obtained by PCR amplifications of DNA extracted directly from the acetification container. Bacterial composition was analyzed by RFLP-PCR of 16S rRNA gene, Temporal Temperature Gradient Gel Electrophoresis (TTGE) separation of amplicons containing region V3-V5 of 16S rRNA gene and cloning of those amplicons. TTGE bands and clones were grouped based on their electrophoretic pattern similarity and sequenced to be compared with reference strains. The main microorganism identified in vinegar was Acetobacter pasteurianus, which at the end of the acetification process was considered to be the only microorganism present. The diversity was the highest at 2% acetic acid, where indefinite species of Gluconacetobacter xylinus/europaeus/intermedius were also present. PMID:18571262

Ilabaca, Carolina; Navarrete, Paola; Mardones, Pamela; Romero, Jaime; Mas, Albert

2008-08-15

458

Application of capillary electrophoresis combined with a modified BCR sequential extraction for estimating of distribution of selected trace metals in PM2.5 fractions of urban airborne particulate matter.  

PubMed

The capillary electrophoresis (CE) method combined with a sequential extraction was applied to determine the distribution of Fe, Zn, Cu, Mn and Cd in urban ambient air PM2.5 samples. PM2.5 was collected on Teflon filters with dichotomous sampler, and the modified extraction procedure following the BCR leaching procedure was used to chemically fractionate metals into "easily exchangeable" with water, "acid extractable" with 0.11 mol/l acetic acid, "reducible" with 0.1 mol/l hydroxylamine hydrochloride acidified to pH 2.0 with nitric acid, and "oxidisable" with oxidation by 8.8 mol/l hydrogen peroxide (H2O2) followed by extraction with 1.0 mol/l ammonium acetate. Based on the obtained results it was concluded that the application of the studied methodology provides chemical fractionation data that reflect the general sources and potential health hazards of the studied metals. PMID:15686754

Dabek-Zlotorzynska, Ewa; Kelly, Meghan; Chen, Heidi; Chakrabarti, Chuni L

2005-03-01

459

Electromembrane extraction of heavy metal cations followed by capillary electrophoresis with capacitively coupled contactless conductivity detection.  

PubMed

Electromembrane extraction (EME) was used as an off-line sample pre-treatment method for the determination of heavy metal cations in aqueous samples using CE with capacitively coupled contactless conductivity detection (CE-C(4) D). A short segment of porous polypropylene hollow fibre was penetrated with 1-octanol and 0.5%?v/v bis(2-ethylhexyl)phosphonic acid and constituted a low cost, single use, disposable supported liquid membrane, which selectively transported and pre-concentrated heavy metal cations into the fibre lumen filled with 100?mM acetic acid acceptor solution. Donor solutions were standard solutions and real samples dissolved in deionized water at neutral pH. At optimized EME conditions (penetration time, 5?s; applied voltage, 75?V; and stirring rate, 750?rpm), 15-42% recoveries of heavy metal cations were achieved for a 5?min extraction time. Repeatability of the EME pre-treatment was examined for six independent EME runs and ranged from 6.6 to 11.1%. Limits of detection for the EME-CE-C(4) D method ranged from 25 to 200?nM, resulting into one to two orders of magnitude improvement compared with CE-C(4) D without sample treatment. The developed EME sample pre-treatment procedure was applied to the analysis of heavy metal cations in tap water and powdered milk samples. Zinc in the real samples was identified and quantified in a background electrolyte solution consisting of 20?mM L-histidine and 30?mM acetic acid at pH 4.95 in about 3?min. PMID:21449072

Kubá?, Pavel; Strieglerová, Lenka; Gebauer, Petr; Bo?ek, Petr

2011-04-01

460

Intracellular reactions in single human granulocytes upon phorbol myristate acetate activation using confocal Raman microspectroscopy.  

PubMed Central

We have obtained new evidence for the occurrence of intracellular NADPH-oxidase activity in neutrophilic and eosinophilic granulocytes upon stimulation with phorbol myristate acetate (PMA). PMA activation leads to a partial translocation of cytochrome b(558) from the membranes of the specific granules to the plasma membrane. It was suggested that NADPH-oxidase activity only takes place in the plasma membrane, leading to an extracellular release of oxygen metabolites because cellular self-destruction can be avoided in this way. The effects of PMA activation were indirectly studied in recent experiments employing scavengers of extracellular superoxide anion and hydrogen peroxide, and support for intracellular NADPH-oxidase activity was obtained. In this paper we use Raman microspectroscopy as a direct method to study intracellular molecular reactions that result from cellular triggering by PMA. The molecular specificity of this microscopic method enables us to show that intracellular reduction of both myeloperoxidase (MPO) and cytochrome b(558) occurs in neutrophilic granulocytes. Control measurement